1
Q
Cardiovascular Basic Principles
A
- in very small organisms (or very porous organisms), vital substances are exchanged through diffusion
- larger animals need circulatory systems to move fluid from its surface to its deepest parts
- two important parts:
- a space for fluid to move in
- pumping mechanism to distribute fluid
- cardiovascular systems are a subtype circulatory systems composed of:
- heart
- blood vessels *blood
2
Q
bulk flow
A
- a pressure gradient causes a liquid or gas to move from one compartment to another, if there is a path for movement
- works for mixtures of substances in a fluid
- high hydrostatic pressure to low
- substances in the fluid usually move with it
- ex. blood, air in lungs, stomach contents, urine
3
Q
flow equation
A
- flow (of volume)= ease of movement x driving force
- dv/dt= pir^4/8nl * (P2-P1)
- ease of movement and driving force control rate bulk flow (fluid flow)
- ease of movement- characteristic of the size of container (wider=more flow, longer= less flow)
4
Q
special circulatory systems
A
- animals evolved a pumping mechanism to circulate fluid and vital substances within the body
- allowed animals to become much larger and less porous since diffusion wasnt limiting exchange
- circulatory fluid:
- one fluid: hemolymph (interstitial fluid)
- two fluids: blood and lymph
5
Q
Porifera- no special circulatory system
A
- sponges
- can be large bc they have pores!
- water moves through the holes
- each of the cells are not that far away from the surface
- water in the ocean is essentially their circulatory system
6
Q
mollusks: special circulatory system
A
- heart (pumping mechanism
- hemocoel- space for fluid to move around in
- one fluid: hemolymph
- some blood vessels that move into the space between cells
7
Q
open vs. closed circulatory system
A
- two types of circulatory systems
- closed- fluid moves through vessels (tubes)
- open- fluid moves through vessels and through body cavities (hemocoel in mollusk)
- circulatory fluids can move faster in vessels because of higher pressure
- higher driving force= more efficient exchange of vital substances
8
Q
open circulatory system
A
- hemolymph circulates in space called hemocoel, bathes all the cells in the body
- most invertebrates
- have blood vessels
- pressure: low
- rate of O2 exchange: low
9
Q
closed circulatory system
A
- blood/lymph circulate in vessels; fluid is exchanged with cells only at capillaries
- vertebrates, cephalopods, annelids (5 hearts)
- pressure: high
- rate of O2 exchange: high
10
Q
open and tracheal circulatory system
A
- 2 separate systems- closed system for gases (tracheal)
- circulatory system not used for gas exchange; a separate system of airways exchanges gasses
- insects
- pressure: low
- rate of O2 exchange: high
11
Q
components of circulatory fluid
A
- one fluid: hemolymph (interstitial fluid (mollusks))
- two fluids: blood and lymph (us)
- most important function of circulatory systems is to circulate fluid (& vital substances)
- vital substances: oxygen, CO2, ions, glucose, water, proteins, fats
- O2 and CO2 are carried by molecules called respiratory pigments
12
Q
respiratory pigments
A
- carry O2 and CO2
- dissolved in hemolymph in most invertebrates
- increases the saturation point of plasma to O2 and CO2 which allows you to carry more
- found in blood cells in 3 groups of animals:
- red blood cells in vertebrates- hemoglobin (iron)
- pink blood cells in some annelids- hemerythrin (iron)
- blue blood cells inmollusks and arthropods- hemocyanin (copper- Cu)
13
Q
blood
A
-composed of: RBC WBC Platelets Plasma -Flows through blood vessels -functions include: Supply vital substances to tissues and organs Remove waste Immune functions (WBCs) Coagulation (platelets) Transport substances Maintain homeostasis
14
Q
Lymph
A
-composed of:
WCBs
Watery fluid (similar to interstitial fluid)
-flows through lymphatic system
-functions include:
-Removes excess interstitial fluid from tissues
-Absorbs and transports fats from digestive system
-Immune functions (bc of present WBC)
-lymphnodes become swollen when ur sick bc of excessive production of WBC
-Is derived from fluid that is pushed through small openings in capillary walls by pressure that originates primarily from the contraction of the heart’s ventricles
-Absorbs and transports fats from the intestines.
-Is returned to the cardiovascular system through ducts with one-way valves.
15
Q
Path of blood in closed circulatory system
A
- left side of heart
- aorta
- arteries
- arterioles
- capillaries
- venules
- veins
- vena cava
- right side of heart
- pulmonary artery
- pulmonary capillaries
- pulmonary veins
16
Q
systemic circulation to/from body
A
- aorta to arteries to arterioles to capillaries to venules to veins to vena cava
- brings blood to the body
- taking blood from the left side of the heart to all the tissues of your body and then returning it back to the right side
- gets deoxygenated
- higher pressure system
17
Q
pulmonary circulation to/from lungs
A
- pulmonary artery to pulmonary capillaries to pulmonary vein
- brings blood to the lungs
- same vessels as in systemic circulation, but lower pressure overall compared to systemic circulation
- right side of heart to lungs and to the left side of the heart
- where is gets oxygenated
18
Q
capillaries
A
- site of oxygen exchange
- all tissues in body have capillary beds
- blood is oxygenated until this step
- exchange of vital substances in blood
- transition
- super small but abundant
- wall is single layer of cells (allows for transport)
- holes called frenestrations
19
Q
pressure in circulation
A
- pressure decreases as blood gets farther from heart
- venules/veins- low pressure
- arteries, arterioles- high pressure
20
Q
artery
A
- thick layer of muscles (smooth muscle fibers)
- small lumen
- vasoconstrict and dilate bc of muscle
- regulate blood pressure
21
Q
veins
A
- thin layers of smooth muscle
- large lumen
- some ability to vasoconstrict (not much)
- stretchy -> blood can pool
- valves- prevents back flow, minimizes pooling, defies gravity
22
Q
vena cava
A
- superior vena cava- coming from arms and head
- inferior vena cava- brings blood from bottom half
- returns blood to right side of heart
23
Q
pulmonary arteries and veins
A
- right side of the heart pumps blood to the pulmonary arteries
- pulmonary arteries pumps deoxygenated blood to lungs
- there are left and right pulmonary arteries and veins for left and right lung
- pulmonary veins bring oxygenated blood from the lungs to the left side of the heart
- exceptions
24
Q
left side of heart
A
- higher pressure system
- more muscle tissue
- this is because the length of the vessels in systemic circulation are longer (compared to pulmonary circulation)
- ease of movement is reduced bc of length -> increased pressure (driving force)
25
rate of flow
- equal in pulmonary and systemic circulation
| - otherwise we would have a back clog of blood
26
bulk flow of blood and lymph
in the capillaries...
1. fluid moves from blood to interstitial fluid through bulk flow at capillaries
2. fluid moves from interstitial fluid to lymphatics through bulk flow
3. lymphatics empty back into blood circulation
- net loss of fluid in the capillaries -> that fluid is picked up by lymphatics and returned back to circulation
27
two pressures contribute to bulk flow out of capillaries
- hydrostatic pressure (Ph)- higher pressure in blood vessels compared to interstitial space pushes fluid out into interstitial space
- colloid osmotic pressure (pi)- higher protein concentration in plasma compared ot interstitial space draws water into capillaries
- if Ph > pi then net filtration (movement out of capillaries)
- if Ph < pi then net absorption (movement into capillaries)
28
anatomy of bulk flow in capillary
- on the arteriole end- Ph > pi -> net filtration
- as you let fluid out the driving force decreases and eventually Ph < pi; however gradient remains
- the point where Ph=pi is closer to venule side; therefore there is more filtration -> net loss of fluid (this is why we need lymphatic system to bring it back)
- closer to the venule side Ph < pi which means net absorption
29
electrical impulse
-originate
| in the left atrium
30
vessels
- aorta
- vena cava
- pulmonary artery
- pulmonary vein
31
chambers
- left atrium
- left ventricle
- right atrium
- right ventricle
- septum
32
valves
- do not contain contractile tissue (they are just connected)
- these valves need to be pushed open from pressure gradients
- aortic semilunar
- pulmonary semilunar
- right AV/tricuspid
- left AV/bicuspid
33
directions
- apex- bottom, tip
| - base- top
34
cardiac conducting system- action potentials
-SA node -> internodal pathways -> AV node -> AV bundle -> bundle branches -> purkinje fibers
35
coronary arteries and veins
- blood vessels that provide your heart with vital nutrients
- provides heart with its own blood supply
- heart doesnt use the blood it pumps
36
chordae tendineae
- heart strings
- holds the valves in place
- makes sure they dont fold backward
- prevents back flow
37
right AV valve
- tricuspid valve
- 3 valves
- right atrium to right ventricle
38
Pulmonary semilunar valve
-right ventricle to pulmonary artery
39
left AV valve
- bicuspid
- 2 flaps
- mitral valve
- left atrium to left ventricle
40
aortic semilunar valves
-left ventricle to aorta
41
autorhythmic/conducting cells
- specialized muscle cells that conduct action potentials through the heart
- generate the action potentials
- no neuron needed
- pacemaker properties
42
SA node
- sinoatrial node
- on top of the right atrium
- action potentials are initiated here
- spread the action potentials through the internodal pathways
- sets the rhythm for the entire heart (strongest and fastest autorhythmic)
- made up of a bunch of cardiac muscle cells (myocytes) -> autorhythmic myocardium
- depolarizes the fastest
- depolarization rate- 100 times per minute
43
interodal pathways
- where the action potentials are spread and travel from the SA node
- in the right atrium
- much faster when spreading to atrial muscle so it has the chance to contract before action potential is spread down to ventricles
44
AV node
- where the action potentials collect/gather
- located between the atria and the ventricles
- delay here bc action potentials are also being spread to atrial muscle in order to contract before action potential arrive here and goes to ventricles
- depolarization rate-40 times per minute
45
AV bundle and bundle branches
- action potentials spread/travel through this after collecting at the AV node
- along the septum
- av bundle- bundle of his
46
purkinje fibers
- spread the action potential into the contractile ventricles
- ventricles start contracting from the apex of the heart and up
- depolarization rate-25-40 times per minute
47
why does the heart contract from the bottom up
- the exit pathways for the ventricles is the aorta or the pulmonary arteries
- so it needs to squeeze blood upwards
48
what causes heart muscle contraction
- action potentials
| - cardiac cycle is started by the excitation
49
what is the most direct results of heart muscle contraction
- blood pressure changes
- contraction generates pressure changes in the chambers
- pressure gradient allows valves to open and close and blood flow
50
order of steps in heart
action potentials -> muscle contraction -> pressure changes
51
relaxation of the heart
- lack of action potentials
- causes the pressure to be high in ventricle and low in atrium
- the blood does not flow with the pressure gradient bc of valves preventing back flow
52
cardiac muscle
-there a 2 types of cardiac muscle cells: myocytes or cardiac muscle tissue (myocardium)
53
autorhythmic myocardium
- action potentials are initiated here
- *generates the heartbeat rhythm
- pacemaker cells + conducting cells = cardiac conducting system
- primary purpose is not to contract
54
contractile myocardium
- contracts
- shorten
- increase the pressure in the heart
- bulk of heart muscle is contractile myocardium
55
autorhythmic myocardium in the SA node
- spontaneously depolarize in a set rhythm
- generate action potentials all by themselves
- heart can beat on its own
- action potentials spread through contractile myocardium through gap junctions -> contraction
- excites every cell in the heart eventually
56
structure of the contractile myocardium
- intercalated disks connect cardiac cells
- gap junctions transfer depolarization between cells
- NO neuromuscular junction; action potentials start in cardiac conducting system
57
cross bridges
- cardiac muscles still have cross bridges and sarcomeres
- contract just like skeletal muscle
- however, no nmj, nueron, chemical synapse
58
autorhythmic myocardium
- SA noded
- AV node
- Left and right purkinje fibers
- SA is the strongest and set the rhythm for the whole heart
- the other just reinforce
59
which contracts first
atrium then ventricles
| -this is account for in the delay in action potential in the AV node
60
heart block
- disruptions in conduction lead to uncoordinated contractions
- AV node or purkinje fiber pacemaker properties apparent
- when there is a block somewhere along the path the highest bpm in the open path wins
61
SA node action potential- funny channels
- funny channels- spontaneously opening Na/K channels
- when open, they generate "funny current" If: *net influx of Na
- K deflux, but influx of Na is way more
- when open, they cause a gradual graded depolarization
- monovalent cation channel
- voltage gated: open when the cell is hyperpolarized (threshold)
- Ca channels open and rapid depolarization -> close at peak
62
resting membrane potential
does not exist in cardiac autorhythmic cells
- never at rest
- does exist in contractile cardiac muscle (very negative)
63
action potential steps in autorhythmic myocardium
- Net Na entry through funny channels
- voltage gated Ca channels reinforce and are responsible for the rapid depolarization
- at peak: the Ca channels close and K channels open
- rapid K efflux causes repolarization
- K channels close
- repolarization of -60 is when Na channels open (funny channels) -> repeat
64
Contractile cardiac muscle: action potentials (excitation)
0. Depolarization via gap junctions opens voltage gated Na channels -> Na influx
1. voltage gated Na channel inactivation gates close
2. long plateau phase caused by Ca influx
3. repolarization caused by K efflux (voltage gated K channels open)
4. resting membrane potential = equilibrium potential for K= -90 (no hyperpolarization)
- 200 ms- very long (prevents tetanus)
65
why is resting membrane potential for contractile cardiac muscle so negative
- these cells are extremely permeable to K at rest
- resting membrane potential is equal to K equilibrium potential
- no hyperpolarization in these cells
66
why are contractile cardiac muscle action potentials so long
- its important for the refractory period to last as long as the muscle contraction
- action potential = muscle contraction period
- voltage gated sodium channel inactivation gates stay closed during plateau phase -> absolute refractory period
- they stay shut until they are reset to closed position at the end of the action potential (then they can be opened again
- protects the heart from tetanus
- cannot contract constantly
- maintains steady contraction and relaxation cycle
67
Calcium induced calcium release
- action potential travels down cell membrane
- voltage gated DHP activated
- *DHP is not mechanically gated to ryanadine receptors -> they are coupled however
- DHP receptors open and let a little bit of Ca through ad the RYR are *ligand gated receptors -> calcium binds and RYR opens -> releasing a whole lot of Ca into cytoplasm
68
calcium spark
increase in Ca in cytoplasm
69
relaxation phase
- ATP used to pump it back in to the sarcoplasmic reticulum
- *sodium calcium antiporter- secondary active transport (relys on concentration gradient thats made by Na K ATPase)- exchanges calcium for sodium
70
depolarization in contractile cardiac muscle
starts in cardiac conducting system
71
source of calcium ions
- skeletal muscle: SR
| - contractile cardiac muscle: SR and interstitial fluid
72
events in order
action potential in autorhythmic cells in SA node -> excitation spreads through heart -> contractile cells are excited -> excitation contractile coupling sequence -> pressure changes -> blood flow
73
cardiac cycle
- atria contract before ventricles
- left atria and right ventricles contract at the same time
- bulk flow drives movement of blood (primarily Ph- hydrostatic pressure)
- diastole = relaxation; systole = contraction
- four phases:
1. isovolumetric relaxation
2. ventricular filling
3. isovolumetric contraction
4. ventricular ejection
74
ventricular diastole
1. isovolumetric relaxation
- ventricular filling
- pressure is dropping
75
ventricular systole
- isovolumetric contraction
- ventricular ejection
- pressure rising in ventricle
76
isovolumetric relaxation
- both atrial and ventricular muscles are relaxing
- semilunar and AV valves are closed
- blood moving from veins into atria
- pressure in ventricles is dropping
- ventricular volume is constant
- ventricular muscle cells repolarize right before this phase
77
ventricular filling
- when pressure atrium > pressure in ventricle -> AV valve opens
- blood flows from atrium to ventricle
- near end of period, atrium depolarizes and atrial systole starts
- more blood moves into ventricle
- at end of period, ventricular volume at max
- EDV= end diastolic volume
- ventricular volume increase while pressure is the same
- Na entry through the funny channels causes the pacemaker potential of SA nodal cells to gradually become less negative until it reaches threshold
78
isovolumetric contraction
- ventricle starts to contract, increased pressure pushed the AV valves closed
- lub
- pressure in ventricles increases rapidly
- SL valves still closed
- nowhere for blood to go
- ventricular muscles cells depolarize at the start of this phase
79
ventricular ejection
- when pressure in ventricles > pressure in arteries -> SL valves open
- ventricle is still contracting, pressure in ventricles keeps rising
- blood moves into arteries
- ventricular volume is at minimum
- ESV= end systolic volume
- the cytosolic concentration of calcium in the contractile cells of the ventricle is the highest during this phase
80
transition to ventricular diastole
- ventricle relaxes (start of isovolumetric relaxation)
- pressure in ventricle rapidly decreases
- when pressure of ventricle < pressure in arteries -> SL valve closes
- dub
- and the cycle starts again
81
End Diastolic Volume (EDV)
- maximum amount of blood in ventricle before contraction
| - at the end of ventricular filling
82
End systolic volume (ESV)
- minimum amount left in ventricle after contraction
| - at the end of ejection
83
stroke volume (SV)
- amount of blood expelled in one contraction
| ex. EDV-ESV=SV
84
right heart volumes=
left heart volumes
85
cardiac output=
- volume of blood pumped in one minute
| - cardiac output= heart rate x stroke volume
86
heart rate=
-heart rate= number of cardiac cycle/minute
87
ms to minute
800ms -> .8 s -> .8/60
88
pulse pressure
systolic (systole, high) - diastolic (diastole, low) in arteries
-normal- 120/80 therefore pulse pressure is 40
89
pressure in arteries
- daistolic pressure increases in the arteries -> bc arteries are tube always exerting pressure
- systolic pressure decreases
90
mean arterial pressure
1/3 of pulse pressure + diastolic pressure
- 1/3 because heart spends more time in diastole than systole
- cardiac output x resistance
- cardiac output = (1/R) x mean arterial pressure
91
systolic pressure
-pressure in arteries at the end of systole
92
diastolic pressure
-pressure in arteries at end of diastole
93
resistance
- radius of blood vessels
- total peripheral resistance
- R=8nL/pir^4
- n=viscosity of blood
- L=total length of vessels
- r=total radius of vessels
94
is edema more likely to result from high mean arterial pressure or low
- high
- hydrostatic pressure and mean arterial pressure are direct relationship
- this means filtration
- swelling
95
an increase in end diastolic volume will not cause
- an increase in end systolic volume
- just bc one increases does not mean the other
- the heart works harder to pump more out
96
in a heart with an intact conduction system, the rate of SA node action potentials equal the rate of AV node action potentials
- true
- SA node sets rhythm for entire heart
- happens at the same rate
- delay doesnt disrupt this
- this will only change if there is a block
97
the rapid depolarization phase of cardiac action potentials is caused by Na influx in both autorhymthic and contractile cells
- false
| - autorhythmic is depolarized by Ca influx
98
equilibrium potential for k
= membrane potential practically
99
the pressure inside the left ventricle exceeds the pressure in the aorta. Which is correct
- this means ventricles are in systole
- left ventricular volume is decreasing
- left AV valve is closed- prevents back flow must be closed
- the pressure in the ventricle is causing the blood to want to move out to aorta
100
two branches of the nervous system
- peripheral
| - central
101
central nervous system
-your brain and spinal cord
102
peripheral nervous system
- sensory and motor (efferent) division
| - efferent- go to muscles and glands (effectors)
103
effectors
-muscles and glands
104
Sensory division of PNS
-detects a signal from sensory receptors
-sensory receptors stimulate sensory neurons (afferents)
-signal is sent to central nervous system (brain or/and spinal cord)
-response is cordinated by efferent neurons (motor neurons)
-
105
efferent neurons
- can be autonomic neurons (involuntary) or somatic motor neurons (voluntary)
- somatic- skeletal
106
autonomic neurons
- sympathetic
- parasympathetic
- cardiac, smooth muscle, glands
- can slow or speed up heart rate but is not the cause of the heart beat*
107
neuron
individual cell
108
nerve
- bundles of neuron axons (mostly) in the PNS
- sensory nerves, motor nerves, mixed nerves
- ex. sciatic nerve- longest nerve, starts in lumbar spinal cord a goes down to foot (motor and sensory motor neurons)
109
tract
- bundles of neuron axons entirely in the CNS
| - ex. corticospinal tract- from motor cortex (head) down to lumbar spinal cord
110
ganglion/ganglia
- clusters of neuron cell bodies in the PNS
- acts as mini integration centers
- outside the CNS
- similar to nucleus in CNS
- exception- basal ganglia (in CNS)
111
nucleus/nuclei
-clusters of neuron cell bodies in the CNS
112
Regions of CNS
- white matter- axons (due to myelin)
| - grey matter- cell bodies/synapses (lack myelin)
113
axon hillock
- beginning of the axon where action potentials are generated
- this is where the voltage gated sodium channels are -> graded -> action potential
114
direction of action potential down a neuron
dendrites to axon terminal bouton
115
anatomy of sensory neurons
- cell body is half way down
| - still travels from dendrites to axon terminal
116
interneurons of CNS
- lie entirely in the CNS
| - diverse shapes and directions of action potentials
117
schwann cells and olidogendrocytes
- schwann cells- PNS
- olidgodendrocytes- CNS
- wrap around axon and form insulating myelin sheaths
- nodes of ranvier are gaps in insulation
118
satellite cells
- PNS
- nonmyelinated schwan cells
- support cells in the PNS
119
astrocytes
- CNS
- several subtypes
- multiple roles
- examples:
- wrap around capillary walls and provide a filter
- source of neural stem cells
- take up K, water, neurotransmitters
- secrete neurotrophic factors
- *help form blood-brain barrier- filtration system between the blood in the capillaries and the brain itself
- provide substrates for ATP production
120
microglia
- CNS
- specialized immune cells
- scavengers
121
ependymal cells
- CNS
- one source of neural stem cells
- form barriers in the CNS
- ex. barrier between compartments- barrier in the ventricles of the brain
- source of neural stem cells
122
shwann cells
- help form myelin sheaths with oligodendrocytes
- secrete neurotrohpic factors
- starts as a single cells and then begins to wrap in multiple layers as it rotates (more insulated) -> faster
123
superior
- towards the top
| - cephalic
124
proximal
towards trunk
125
distal
-distant from trunk
126
inferior
towards the bottom
127
medial
-towards midline
128
lateral
-towards the side
129
anterior
- towards front
| - ventral
130
posterior
towards back
| -dorsal
131
caudal
-towards butt
132
a ganglion in the PNS is like _ in the CNS
-a nucleus
133
evolution of nervous systems
- unicellular organisms do not have integrating centers, but use resting membrane potentials to coordinate activity (bc they are one cell)
- cnidaria possess a nervous system termed a nerve net
- flatworms exhibit primitive brains and nerve cords
- annelids have simple brains and ganglia along nerve cords
- simple reflexes can be integrated at the ganglia without the brain
- complex brains are associated with complex behaviors
- in vertebrate evolution, the most dramatic change is seen in the forebrain region, which includes the cerebrum (larger)
134
collection of cell bodies
- integrating center
| - without the brain
135
three regions
- Hindbrain
- midbrain
- forebrain
136
forebrain
- becomes very developed
- largest
- dominates the brain
137
development of the human CNS
- *CNS (brain and spinal cord) develops from a hollow tube
- begins as a group of cells called the neural plate- neural crest migrate within the plate cells
- plate fuses to create a neural tube at about day 23 -> neural crest cells become peripheral nervous system
- by week 4 anterior portion differentiates into specialized regions (forebrain, midbrain, and hindbrain) -> posterior portion becomes the spinal cord
- by week 6, the 7 divisions of the CNS are present:
- forebrain becomes cerebrum and diencephalon
- hindbrain becomes cerebellum, pons, and medulla oblongata
- formation of the ventricles
- by week 11, the cerebrum is enlarged:
- surrounds the diencephalon, midbrain, and pons
- cerebellum and medulla oblongata remain visible
138
7 divisions of the CNS
- midbrain
- spinal cord
- pons
- medulla oblongata
- cerebellum
- cerebrum
- diencephalon
139
ventricles
- fluid filled spaces in the brain
| - circulate cerebral spinal fluid
140
visible parts of brain
- cerebellum
- cerebrum
- medulla oblongata
- pons really hard to see
141
follic acid
-closes the neural plate
142
grey matter
- unmyelinated nerve cell bodies
- clusters of cell bodies in the CNS are nuclei
- dendrites
- axon terminals
- lots of synapses bc of cell bodies
143
white matter
- myelinated axons
| - axon bundles connecting CNS regions are tracts
144
the spinal cord
- segments associated with spinal nerves
- spinal nerve branches into two roots
- dorsal root neurons carry sensory information
- dorsal root ganglia contain afferent (sensory) cell bodies
- afferent neurons connect with interneurons in the dorsal horns
- ventral roots carry motor information from the CNS to muscles and glands
145
Afferent neurons
- connect with interneurons in the dorsal horns
| - exception: monosynpatic reflex pathways -> connects directly with motor neuron
146
dorsal root
- carries sensory information to CNS
- nerve going into the back on spinal cord
- afference carries through here
- PNS
147
Ventral root
- carries motor information to muscles and glands
| - nerve coming out of the front spinal cord
148
dorsal horns
- contain sensory information from internal organs (visceral) and somatic sensory neuron axon terminals and interneuronal cell bodies
- usually where the synapse is
- grey matter
- CNS
149
ventral horns
- contain somatic motor neuron cell bodies
| - gray matter
150
white matter
- divided into columns of tracts
- asscending tracts take sensory information to the brain (dorsal)
- descending tracts carry motor signals from the brain (ventral)
- propriospinal tracts stay in the cord- take information from one region to another ex. walking -> arms and legs
151
spinal reflex
- integrated in the spinal cord
| - do not need brain
152
reflex
- awareness happens after in brain
| - conscious perception of pain will be after reflex
153
which is true for doral root but not a dorsal horn
- contains a neuronal cell bodies
- is located within the spinal cord
- *is located outside the spinal cord
- carries incoming sensory information
- contains two separate nuclei
154
medulla oblongata
- controls involuntary functions:
- blood pressure, breathing, swallowing, vomiting
- relays information from spinal cord to cerebrum & vice versa
- hindbrain
155
pons
- controls breathing
- relays information from cerebellum to cerebrum
- hindbrain
156
cerebellum
- coordinates movement- posture, gait
- important in motor learning
- helps process sensory information
- hindbrain
- processes somatic senses
- absence of cerebellum can impair talking, walking, and can make you feel dizzy
157
hindbrain
- medulla oblongata
- pons
- cerebellum
158
midbrain
- controls visual and auditory reflexes
- coordinates eye movement
- midbrain pons and medulla together make up the brain stem
159
brain stem
-midbrain, pons and medulla
160
forebrain
-diencephalon and cererbrum
161
diencephalon
- thalamus- the executive secretary: processes sensory information and then relays some of it to cerebrum (directs)
- hypothalamus- coordinates homeostasis
- glands: pineal and pituitary
162
cerebrum
- basal nuclei (basal ganglia)- control of body movement- grey matter, lots of synapses, automatic movement
- limbic system- primitive emotional functions and learning and memory
- cerebral cortex- grey matter, the wrinkles, processing goes on here
163
limbic system
- in the cerebrum
- primitive emotional functions
- learning and memory
- made up of cingulate gyrus, hippocampus, and amygdala
- olfactory bulbs in the nose -> smell is linked to memory
- emotional events have a strong memory -> PTSD
164
impairment of basal nuclei
- causes low dopamine release
- parkinsons disease
- basal cells are associated with automatic control
- things like walking can be disrupted
- needs external cue
165
cerebral cortex
- from a functional viewpoint, it can be divided into 3 specializations
- sensory areas- input translated into perception (awareness)
- motor areas- direct skeletal muscle movement
- association areas- integrate information from sensory and motor areas
166
4 lobes of the cerebral cortex
- frontal lobe
- parietal lobe
- occipital lobe
- temporal lobe
167
frontal lobe
- primary motor cortex is here
- motor association areas were actions are planned
- plan and execute motor actions
- voluntary
- also is personality, impulse control
168
parietal lobe
- sensory
- senses are processed here
- somatosensory cortex
169
occipital lobe
-visual sensory
170
temporal lobe
-hearing sensory
171
association areas
- in each lobe
- integrate information
- ex. hearing and seeing someone
172
wenickes area
- important for understanding words
- can be damaged due to stroke
- if this is damaged they can speak but it doesnt make sense
- aphasia
173
brocas area
- generating words
- if this is damaged they can understanding but speaking is difficult
- aphasia
174
cerebrospinal fluid
- CSF
- salty solution similar to plasma
- circulates
- surrounds entire brain
- contained within subarachnoid space
- flows from ventricles to subarachnoid space to return to plasma by villi
- provides physical and chemical protections to brain
- liquid cushion
- buffers the brain
- Glucose is a hydrophilic organic compound that can be found in blood plasma, interstitial fluid, and CSF.
- (does not have high albumin; not due to the contractile activity of ependymal cells)
175
blood brain barrier
- protects the brain
- highly selective permeability of brain capillaries
- additional layer around capillaries to protect
- astrocytes foot processes promote tight junctions between endothelial cells
- additional filter
- protects brain from toxic water soluble compounds and pathogens
- small lipid-soluble molecules cross the blood brain barrier
- membrane transporters move glucose through blood brain barrier (bc it normally cannot cross)
176
neural tissue: special metabolic requirements
- neurons need a constant supply of oxygen and glucose
- brain receives 15% of blood pumped by heart
- oxygen- passes freely across blood brain barrier
- glucose:
- membrane transporters move glucose from plasma into the brain interstitial fluid
- brain responsible for about half of bodies glucose consumption
- progressive hypoglycemia leads to confusion, unconsciousness, and death
177
special senses
- from head
- vision
- hearing
- taste
- smell
- equilibrium
178
senses we are not conscious of
```
somatic (from body)
-muscle length and tension
-proprioception
visceral stimuli
-blood pressure
-blood glucose concentration
-interal body temp
-osmolarity of body fluids
-lung inflation
-pH of cerebrospinal fluid
-pH and oxygen content of blood
```
179
somatic senses
- from the body
- touch
- temperature
- pain
- itch
- proprioception
180
stimulus
physical energy that is detected by a sensory receptor
- receptor acts as a transducer
- stimulus-> sensory receptor graded potential -> threshold -> action potential in sensory neuron -> CNS
181
sensory transduction
- the process of converting sensory stimuli to action potential
- transducer the energy into a sensory receptor graded potential -> action potential in sensory neuron
182
chemoreceptors
- respond to chemical ligands
| - taste, smell, pH of blood, blood glucose concentration
183
mechanoreceptors
- respond to mechanical energy pressure and sound (wave)
- hearing, touch, distention of GI tract, lung inflation
- includes baroreceptors (blood pressure)
- majority
184
thermoreceptors
- response to temperature
| - in skin and hypothalamus
185
photoreceptors
-for vision respond to light
186
complex neural receptors
- nerve endings (receptors) are surrounded by connective tissue
- enclosed nerve ending
- ex. pressure receptor
187
nonneural sensory receptors
- receptor is a separate cell
- graded potential in the receptor cell causes the release of neurotransmitter at the synapse
- separate sensory neuron generates action potential to CNS
- ex. hair cell in ear for hearing
188
simple receptor
ex. pain
189
all sensory information passes through
- with exception of smell (goes straight to olfactory bulb)
- the thalamus before it goes to relevant sensory cortexes
- ex. stimulus of eye goes to thalamus then visual cortex
190
sensory modality
- is coded by the sensory neurons that are activated and where neurons terminate in brain
- ex. taste, vision, proprioception
191
location
of the stimulus is coded by which receptive fields are activated
192
all sensory information gets sent to the brain as a series of action potentials. how does this information get interpreted and differentiated
- sensory modality
- location
- intensity
- duration
193
intensity
-of the stimulus is coded by the number of receptors activated and the frequency of activation
194
duration
- of the stimulus is coded by the duration of activation
- slow adapting and fast adapting
- receptors adapt: tonic receptors (slow adapting) vs. phasic recptors (fast adpating)
- ex. when you go into a room and smell cookies and go nose blind
195
sensory coding
- indicates intensity and duration
| - not were it is coming from or what kind of stimulus
196
labeled-line principle
- the perceived sensation (modailty and location) depends on the connections made by sensory neurons with specific CNS circuits that activate distinct regions of sensory cortex in the brain
- action potentials in a single sensory neuron carry information about intensity and duration of a stimulus- but not its modality or quality
197
location coding
-location of stimulus gets mapped to a specific location in your somatosensory cortex
198
a surgeon probes part of the somatosensory cortex that receives info from the eye. If it depolarizes what sensation will it cause
- touch to the eyelid
- its not light flashing because vision and light is not somatic (it would work in occipital lobe)
- somatic is touch
199
efferent division of the peripheral nervous system
- efferent neurons carry command from CNS to the muscles and glands of the body (effectors)
- two subdivisions:
- voluntary/somatic motor neurons
- autonomic neurons
200
efferent divison: somatic motor neurons
- control skeletal muscles
- mostly voluntary
- consists of one neuron
- originates in the CNS- in brain or ventral horn of spinal cord
- myelinated, very long, always excitatory
- terminal branches close to target and each terminal innervates a single skeletal muscle fiber (target)
- neuromuscular junctions
201
efferent division: autonomic neurons
- control smooth muscle, cardiac muscle, many glands, and some adipose tissue
- mostly involuntary
- two subdivision:
- sympathetic branch (fight or flight)
- parasympathetic branch (rest and digest)
- anatomically distinguishable
- best distinguished by their relative activity under certain situations
- these subdivisions work in balance (not one extreme or other)
202
neuromuscular junction (NMJ)
- synapse between somatic motor neuron and skeletal muscle fiber
- neurotransmitter: ACh
203
autonomic control centers
-mostly in brain stem and hypothalamus
204
antagonistic control is a hallmark of the autonomic division
- most internal organs are under antagonistic control
- one autonomic branch is excitatory, and the other branch is inhibitory
- innervated by both the parasymp and symp
- some exceptions to dual antagonistic control are sweat glands and smooth muscles in most blood vessels (vasoconstriction and dilation) -> only sympathetic innervation
205
autonomic pathways have two efferent neurons in series
- PREGANGLIONIC NEURON:
- first neuron in chain with cell body located in CNS
- projects from CNS to an autonomic ganglion outside the CNS
- synapses with postganglionic neuron
- POSTGANGLIONIC NEURON
- second neuron in chain with cell body located in` the autonomic ganglion
- projects from an autonomic ganglion to the target tissue
- synapses with target cell
206
sympathetic branch
- originates in thoracic and lumbar (middle) regions of the spinal cord
- sympathetic ganglia in chains along either side of the vertebral column
- on average constrict blood vessels through alpha receptors
- heart rate and force of contraction increases through beta adrenergic receptors
- short preganglionic neuron and long postganglionic
- use ACh and norepinephrine
- adrenergic recptor on target
207
parasympathetic branch origination
- originates in the brain stem and sacral (lower) region of spinal cord
- slows rate of heart
- no affect on vasoconstriction/dilation
- parasympathetic ganglia located on or near target organs
- long preganglionic neruons
- short postganglionic or sometimes even on target tissue
- only use ACh
- muscarinic receptor on target
208
vagus nerve
- contains about 75% of all parasympathetic fibers
- also carries visceral sensory information to brain
- mixed nerve- efferent, parasympathetic and sensory fibers
209
baroreceptor reflex
- increase in mean arterial pressure -> activate branches of the autonomic nervous system in attempt to lower BP
- increases firing rate of pressure receptors in arteries
- sends action potentials down sensory neurons to cardiovascular control center in brain stem
- increase parasympathetic outflow and reduce sympathetic outflow to decrease blood pressure
- *increase in parasymapthetic outflow will cause in increase in ACh on muscurinic receptors ->hyperpolarize SA node -> heart rate reduced -> reduce cardiac output -> decrease blood pressure
- *decrease in sympathetic output -> decrease in norephinephrine -> reduced activation of alpha receptors and beta1 receptors -> decrease heart rate -> decrease force of contraction -> vasodilation -> reduction in resistance and cardiac output -> decrease blood pressure
210
digestive tract
- the sympathetic response- decreases motility and secretion (alpha or beta)
- parasympathetic response- increases motility and secretion
211
beta 1 adrenergic receptors
- increases heart rate and force of contraction
- antagonistic control-muscarinic receptors in the parasympathetic system slows the heart rate
- blocking adrenergic receptors does not affect the postganglionic cell
- increases the intracellular Ca
- found in SA node and ventricular myocardium
212
alpha adrenergic receptors
-activation of receptors increases contraction -> vasoconstriction
-deactivation leads to relaxation -> vasodilation
-there is no parasympathetic affect on this
-found on vascular smooth muscle
-increase intracellular calcium
-
213
exocrine pancreas
- sympathetic response- decreases enzyme secretion (alpha)
| - parasympathetic response- increases enzyme secretion
214
endocrine pancreas
- sympathetic response- inhibits insulin secretion (alpha)
| - parasympathetic response- stimulates insulin secretion
215
g-protein coupled receptor: mAChR
- muscarinic AChRs are found on parasympathetic targe tissue (heart, lungs, digestive tract)
- ACh binding causes G protein activation
- opens K channel
- increased permeability K
- hyperpolarizing graded potnetial
- slows heart rate
- no change in blood vessel diameter
216
constant parasympathetic control
- parasympathetic stimulation hyperpolarizes the membrane potential of the autorhythmic cell and slows depolarization slowing down the heart rate
- slower to reach threshold
- resting parasympathetic tone
- constantly releasing Ach onto the muscurinic receptor to slow heart rate
- SA node is 100 bpm -> thats why average heart rate is 60-80
217
sympathetic control
- sympathetic stimulation increases HR and heart contractility via beta1 receptors
- increases intracellular Ca -> pacemaker cells depolarize faster
- reach threshold faster
- more calcium means more cross bridges which means more contraction too
- systolic volume decreases because heart is contracting harder -> increases stroke volume -> increase in mean` arterial pressure
218
g protein coupled receptor using cAMP: beta 2 adrenergic receptors
- reduce intracellular Ca
- found on vascular smooth muscle (and other places)
- activation of beta 2 adrenergic receptors increases relaxation -> vasodilation
219
sympathetic control of MAP
- sympathetic stimulation can change resistance (total peripheral resistance)
- E and NE have different effects on adrenergic receptors
- alpha adrenerhic receptor activation = vasoconstriction
- beta 2 adrenergic receptor activation = vasodilation
- overall, sympathetic stimulation leads to increased resistance by decreasing the total radius of blood vessels
- MAP=(SV x HR) x R
- R=8nl/pir^4
220
alpha
dominates beta 2
221
CNS control of MAP
- MAP sensed by baroreceptors that fire action potentials down afferents
- high MAP= increased AP freq
- low MAP=decreased AP freq
- afferents synapse onto interneurons in cardiovascular control centers in medulla
- medulla modulates symp. NS and parasymp. NS outputs
- symp. NS and parasymp. NS outputs change MAP to keep i at homeostatic set point of 93mmHg
222
which of the following pathways contain a ganglion
- sensory (afferent) pathways into the spinal cord
- autonomic (efferent) pathways out of the spinal cord
- NOT somatic (efferent) pathways out of the spinal cord
- ganglion are in the PNS -> somatic is in the PNS however somatic cell bodies are in the CNS (nucleus)
223
sensory afferent ganglion
in dorsal root
224
which are found in a nerve
- afferent axon
- efferent axon
- schwann cells- myelinate
225
molecules that can diffuse through plasma membranes can move across the BBB
-true
226
frequency of action potentials increases
- increase in intensity
| - taste, heat
227
special senses
do not ascending tracts
| -already on brain level
228
muscarininc AChR antagonist will block action potentials in which cells:
- parasympathetic post-ganglionic neurons
- SA node cells (depolarize on their own)
- **None of the above
- mAChR are on the target cell
229
Electrical communication
- within a cell: action and graded potential
| - between cell: electrical synaptic transmissions (gap junctions, cardiac muscle)
230
chemical communication
- within a cell: cell signaling (intracellular pathways: g-proteins)
- between cells: chemical synaptic transmission (NMJ) & endocrine system (systemic transmission)
231
4 defining characteristics of hormone
1. secreted by cells:
- endocrine cells/glands
- neurons (neurohormones)
- cells of the immune system
2. secreted into the blood
3. transported to a distant target
4. exert their effect at very low concentrations (10^-9,10^-12)
- often first messengers
232
basic endocrine signaling
- hormone is a chemical secreted into blood by a cell or group of cells for transport to a distant target, where it exerts its effect at very low concentration
- many hormones are first messengers
- specific responses by specific receptors
- methods of synthesis and secretion of hormone, its speed and action, how long it lasts, etc. are determined by the class of chemical signal it belongs to:
- peptides
- steriods
- amines (catecholamines)
233
amines examples
-epinephrine
-norephiephrine
-can act as neurotransmitters and hormones: neurohormones
-
234
steriods examples
```
-cortisol
sex hormones:
-testosterone
-DHT
-estrogen
-progesterone
```
235
peptides examples
- insulin
- glucagon
- ACTH
- CRH
- ADH/AVP
- alpha mullerian hormone
- FSH
- LH
- GnRH
- Growth hormone
- GHRH
- (everything else)
236
peptide hormones
- made in advance
- stored in secretory vesicles
- released through exocytosis (hydrophilic)
- transported through blood through dissolved plasma
- half life: short
- receptors found on cell membrane
- activation of second messenger systems -> may activate genes
- modification of existing proteins and induction of new proteins synthesis
237
steriod hormones
- synthesized on demand from precursors
- released through simple diffusion (hydrophobic)
- transported through blood by being bound to carrier proteins
- half-life: long (bc of carrier proteins)
- receptors found inside cytoplasm of nucleus (sometimes membranes too)
- activation of genes for transcription and translation -> may have nongenomic actions
- induction of new protein synthesis
- slower and longer lasting mechanisms
- can cross the blood brain barrier
238
amine hormones
- made in advance
- stored in secretory vesicles
- released through exocytosis (hydrophilic)
- transported through blood by being dissolved in plasma
- half life: short
- receptors found on cell membranes
- activation of second messenger systems
- modification of existing proteins
239
types of membrane receptors: peptide/amine
- g-protein
- tyrosine-kinase
- > second messengers
240
stimuli for hormone release
- humoral
- neural
- hormonal
241
humoral sitmuli
-ions or molecules in environment
-release of hormone in response to substance in the blood that is not a hormone/neurohormone/neurotransmitter
ex.
-high glucose -> insulin
-low glucose -> glucagon
242
neural stimuli
-release of hormone in response to activation of the nervous system
ex.
-parasympathetic nervous system ACh/insulin
-sympathetic nervous system ACh/epinephrine
-posterior pituitary hormones
243
hormonal stimuli
- one hormone stimulate the release of a second hormone
| - hypothalamic/anterior pituitary pathways
244
humoral: high glucose -> insulin
- high glucose in the blood stimulates the release of insulin -> stores glucose
- beta cells on pancreas are stimulated -> release insulin
- high insulin affects liver, muscle, fat tissue, etc.
- this cause glyoclysis, glycogenesis, lipogenesis (forming glycogen to store away)
- liver stores glucose away as glycogen
- increase glucose into fat cells, muscles (away from blood)
- results in decrease glucose in the plasma
- this reduces stimulation of beta cells (negative feedback)
245
humoral: low glucose -> glucagon
- low glucose levels in the blood stimulates release of glucagon
- inhibits beta cells of the pancreas -> decrease insulin -> inhibits the storage of plasma glucose
- alpha cells of the pancreas are stimulated -> increase release of glucagon into blood
- glucagon acts on the liver -> breaks down glyocgen and releases glucose from storage into blood (glycogenolysis, gluconeogenesis, ketones)
- increase in plasma glucose
- plasma glucose (and ketones) are used by brain and peripheral tissues
246
neural: parasympathetic ACh/insulin
- eat a meal
- distension of GI tract wall
- stretch receptors
- increase sensory neuron input to the CNS
- increase parasympathetic output (rest and digest)
- neurotransmitter released on the beta cells of pancreas -> stimulated (mACh receptors)
- increase in insulin
- high insulin affects liver, muscle, fat tissue, etc.
- this cause glyoclysis, glycogenesis, lipogenesis (forming glycogen to store away)
- liver stores glucose away as glycogen
- increase transport/storage of glucose into fat cells, muscles (away from blood)
- results in decrease glucose in the plasma
- this reduces stimulation of beta cells (negative feedback)
247
neural: sympathetic/epinephrine
- preganglionic sympathetic nervous system cell that starts in spinal cord and ends in the adrenal gland
- in response to ACh from action potential -> modified postganglionic sympathetic neuron in adrenal medulla (middle of adrenal gland) releases epinephrine (neurohormone) that enters the blood
- acts on targets tissues that have adrenergic receptors
248
pituitary gland
- hangs of the hypothalamus
- anterior and posterior portions
- posterior- neural release
- anterior- hormonal release
249
neural: 2 posterior pituitary hormones
- hypothalamic neurons that project into the posterior pituitary gland
- neurohormones in the hypothalamus are packaged in cell body of neuron
- vesicles are transported down the cell
- vesicles containing neurohormones are stored in posterior pituitary
- when depolarized these hormones are released into blood
- these hormones are:
1. vasopressin (AVP)- (antidiuretic hormone) stimulus is neurons that sense blood osmolarity, targets kidney, responses is water resorption and increased BP
2. ocxytocin- stimulus is sensory neurons, targets brain, uterus, cervix, mammary glands, responses are behavioral responses, labor and delivery, and milk let-down
250
hormonal: hormone stimulated hormone release at anterior pituitary
- neural stimulation causes hypothalamic neurons release of neurohormones (hormone A: releasing or inhibiting) into the capillary beds in portal system (at the level of the hypothalamus)
- hormones arrive at anterior pituitary from the portal veins and binds receptors on a subset of cells in anterior pituitary
- stimulates release of hormone B (tropic hormone) into second capillary bed in anterior pituitary
- this hormone travels through systemic circulation and binds to receptors on targets endocrine organs -> mammary glands, musculoskeletal system, thyroid gland, adrenal gland, gonads (ovary, testes)
- target endocrine organ cells release hormone C into capillary beds in these target endocrine organ
- this hormone travels through systemic circulation and binds to receptors on target cells
251
portal veins
- 2 capillary beds in the anterior pituitary
| - portal veins connect these beds
252
hormonal: hypothalamic-anterior pituitary axis
-hypothalamus releases hormone A (releasing or inhibiting hormone) into capillary beds in portal system
253
hormone A
- releasing or inhibiting
- hypothalamic hormones
- ex. TRH: thyroid releasing hormone
254
hormone B
- anterior pituitary hormones
- tropic hormones
- cause the release of other hormones
- ex. TSH: thyroid stimulating hormone
255
hormone C
- endocrine targets and the hormones they secrete
| - ex. thyroid hormone
256
cortisol hormone A,B,C
- hormone A- CRH: corticotropin releasing hormone, secreted by hypothalamus, releases hormone B
- Hormone B- ACTH: adrenal corticotropin hormone, secreted by anterior pituitary
- hormone B acts on adrenal cortex and releases hormone C
- hormone C- cortisol, secreted by adrenal cortex (steriod)
257
hormonal release of hormones: positive and negative feedback
-CRH: secreted by hypothalamus, half life: 9 min,
258
cortisol
steroid hormone
| -Cells of the anterior pituitary gland express cortisol receptors (i.e., glucocorticoid receptors)
259
Cortisol secretion and action
- circadian rhythm or stress stimulates hypothalamus neurons to release CRH
- this stimulates the release of ACTH from the anterior pituitary
- this acts on the adrenal cortex that release cortisol
- cortisol acts on immune system (-> function suppressed), liver (-> gluconeogenesis), muscle (-> protein catabolism), adipose tissue(-> lipolysis)
260
adrenal medulla: sympathetic branch
- on top of kidneys
- produce neurohormones (epinephrine)
- adrenal medulla is innervated by neurons that come from the spinal cord (sympathetic branch)
- when sympathetic neurons are activated the chromaffin cells in the adrenal medulla releases epinephrine
261
chromaffin
- respond to activation of sympathetic nervous system
- release epinephrine in the adrenal medulla
- epinephrine into the blood stream (hormone)
262
short term response to stress
- *stimulus: neural (activated by nervous system)
- epinephrine and norepinephrine are released
- secreted by the adrenal medulla
- sympathetic branch
- epinephrine -> alpha and beta receptors -> heart rate increase, BP increase
263
long term response to stress
- stimuli: *hormonal, neural
- cortisol and aldosterone
- secreted from adrenal cortex
- sustained activity in the hypothalamic pituitary axis
- CRH, ACTH, cortisol pathway
264
cells in sexual reproduction
- each parent produces haploid (1n) cells called gametes in meiosis
- larger nonmotile gamete produced by the female is called the ovum
- the smaller motile gamete produced by the male is called spermatozoon (sperm)
- one of each fuse to form a diploid (2n) zygote in the process of fertilization
265
human male reproductive anatomy
- external: scrotum & penis
- internal:
- testes (gonads)- produce sperm cells and hormones
- accessory glands- secrete products essential to sperm movement
- ducts- carry sperm and secretions
266
pathway of sperm (ejaculation)
- originate in the testes in the *Seminiferous tublues
- sperm is pushed into the *Epididymis where sperm becomes motile
- move to *Vas deferens around the bladder
- pass the seminal vesicle, prostate gland, and bulbourethral gland -> these combine with the sperm to create semen (support & nourishment)
- *Ejaculatory duct
- *Urethra
- *Penis
- outside world
267
female reproductive anatomy
- external: clitoris, labia (majora, minora), vaginal opening
- exhibit erection (clitoris) and enlargement during arousal
- internal: ovaries (gonads), ducts and chambers to conduct gametes and house embryo & fetus
268
chromosomes
- 23 pairs of chromosomes
- 22 pairs autosomes
- 1 pair of sex chromosomes (XX, XY)
- XX- female
- XY- male
269
bipotential stage: internal
- 6 week embryo
- mylerian duct
- wolffian duct
- gonad (bipotential- could be male or female)
- IF FEMALE:
- the gonadal cortex will become ovary, gonadal medulla regresses
- wolffian duct regresses
- mullerian duct becomes fallopian tubes, uterus, cervix and upper 1/2 of vagina
- IF MALE:
- the gonadal cortex regresses (becomes nothing)
- gonadal medulla forms a testis, wolffian duct forms epididymis, vas deferens, and seminal vesicles
- mullerian duct regresses
270
bipotential stage: external
- 6 week embryo
- labioscrotal swelling
- genital tubercle
- urethral groove
- urethral fold
- IF FEMALE:
- gential tubercle forms clit
- urethral folds and grooves form labia minora, opening of vagina and urethra
- labioscrotal swelling form labia majora
- IF MALE:
- genital tubercle forms glans penis (tip)
- urethral folds and grooves form shaft of penis
- labioscrotal swellings form shaft of penis and scrotum
271
if there are no hormones the embryo...
will default form female characteristics
272
SRY gene
- found on Y chromosome
- directs male development
- produces SRY protein
- protein causes the gonad medulla to differentiate into testes -> if this isnt present then the gonad cortex forms the ovaries
- testes has leydig cells and sertoli cells
- these cells secrete testosterone and anti-mullerian hormone
273
leydig cells
- aka interstitial cells
- in the testes
- stimulated by LH
- secretes testosterone which controls:
- development of wolffian duct into accessory structures
- development of male external genitalia (via DHT)
274
sertoli cells
- in the testes
- stimulated by FSH
- nourish sperm
- regulate sperm development
- secretes anti-mullerian hormone which controls:
- regression of mullerian duct
275
androgens
- male sex hormones
- we get DHT from testosterone
- testosterone, DHT
- if these are present:
- wolffian duct -> seminal vesicle, vas deferens, epididymis
- DHT -> prostate, male external genitalia
276
XX child is exposed to DHT. They while have ovaries and may develop masculine external structures
true
- no SYR -> no internal features
- DHT determines external structures
277
gametogenesis
- germ cell undergo mitosis -> proliferation (oogonium, spermatogonium)
- in females mitosis stops after embryonic development (become birth) -> male mitosis for life
- meiosis starts after puberty
278
female gametogenesis
- primary oocyte doubles DNA (4n)
- produces one ovum -> haploid (1n)
- 3 polar bodies (3n all together) -> discarded
- if ovum is not fertilized it degenerates
279
male gametogenesis
- primary spermatocyte doubles DNA (4n)
| - produces 4 spermatozoon 1n sperm each
280
hypothalamic-pituitary axis control
- hypothalamic neurons secrete GnRH (gonadotropin releasing hormone -> hormone A) into blood
- GnRH travels to anterior pituitary -> stimulates
- anterior pituitary secretes the gonadotropins (hormone B): LH and FSH (lutenizing hormone; follicle stimulating hormone)
- act on the gonads
- LH and FSH promote development of gametes and secretion of sex hormones (testosterone; estrogen. progesterone)
- testosterone -> negative feedback on anterior pituitary ; hypothalamus -> increased T inhibits GnRH, LH, and FSH
- estrogen & progesterone -> negative or positive feedback, depending on concentration
281
sustained high levels of estrogen
- causes positive feedback
| - GnRH, LH, FSH increase
282
the hormonal control of spermatogenesis
- LH acts on leydig cells -> secrete testosterone -> production of sperm and secondary characteristics
- FSH acts on sertoli cells -> secrete products that support the developing sperm (also product androgen binding protein (ABP) that binds to testosterone)
283
testosterone
- steroid
| - needs ABP to be binded in order to move in blood
284
seminiferous tubule
- inside it is surrounded by lumen
- spermatogonium are undergoing mitosis on the outer region
- as you move closer to lumen the cells are more and more mature
- once it reaches the lumen it is mature (not fully) and can be released
- you can find primary spermatogonia and sertoli cells here NOT mature sperm
285
hormonal regulation: female
- uterus has two layers: myometrium (smooth muscle) and endometrium (epithelial layer that changes size, sheds)
- ovaries produce ova and hormones
- structure of ovaries varies with ovarian cycle
- during ovulation ovum is released
- before ovulation, follicle produces hormones (estrogen)
- after ovulation, corpus luteum produces hormones (progesterone)
286
ovary: full cycle
- development of ovum into follicle
- follicle houses the oocyte and endocrine cells that secrete hormones (primarily estrogen)
- during ovulation the follicle ruptures and the oocyte is released
- follice that is left behind becomes the corpus luteum -> secrete hormones (primarily progesterone)
- gradually regresses
- repeat
287
reproductive cycle
```
-28 days
OVARIAN CYCLE
-day 0-14- follicular phase (estrogen)
-day 14 of so- ovulation
-day 14-28- luteal phase (progesterone)
UTERINE CYCLE
-day 0-7- menses (period)
-day 7-14- proliferative phase (endometrium is building)
-day 14-28- secretory phase (hormones secreted to support zygote)
```
288
3 layers of follicles
-antrum- middle fluid fill
endocrine cells:
-granulosa cells- inner layer
-thecal cells- outerlayer
289
follicular phase
- day 0-14
- follicle producing estrogen
- menses phase- in the beginning estrogen is low-moderate -> negative feedback
- proliferative phase- estrogen is increasing until it reaches sustained estrogen levels -> positive feedback -> LH and FSH peak -> ovulation
290
luteal phase
- day 14-28
- secretory phase
- corpus luteum produces progesterone
- progesterone is low -> negative feedback for LH and FSH
291
female has ovaries and uterus removed, what effect would this have on hormone levels
- increase FSH and LH, decreased estrogen and progesterone
- estrogen and progesterone are produced in the ovaries -> decrease
- LH and FSH are produced in the anterior pituitary -> low levels of estrogen and progesterone -> negative feedback -> increased LH and FSH
292
high levels of estrogen will increased GnRH, whereas very high levels of testosterone will decrease
- high estrogen -> positive feedback
| - testosterone is always negative feedback
293
human sexual response
- male response controlled by both sympathetic and parasympathetic
- arousal/erection- parasympathetic
- vasocongestion- causes penis to become erect (holds blood in shaft and is required for sex)
- orgasm/ejaculation- sympathetic- a series of strong muscular contractions at base expel semen
- similar for females but not required to get pregnant
294
fertilization
- ovum is released by the ovaries -> gets picked up by fimbrea
- if ovum encounters sperm in fallopian tubes -> fuse
- sperm go through final maturation steps inside female reproductive tract
- sperm remain viable for up to a week
295
blastocyst
- by the time the zygote reaches the uterus it is a blastocyst
- implants into the endometrium
- has an inner cell mass -> becomes embryo
- outer cells -> chorion -> forms placenta
296
chorion
- secretes human chorionic gonadotropin (hCG)
- stimulates corpus luteum to keep producing progesterone to maintain endometrium (prevents sheding)
- detected in home pregnancy tests
- becomes placenta
- after 7-8 weeks, placenta produces most hCG, E, P
- connects fetus to maternal circulation
297
embryo
0-8 weeks gestation
298
fetus
> 8 weeks
299
hormonal and non-hormonal contraceptives
- progesterone only- mini-pills, injection, implant, intrauterine device
- progesterone and estrogen- pills, vaginal ring, patch
- non-hormonal: barrier methods (condom, diaphragm), copper IUD
300
contraceptives prevent one or more processes
- prevent ovulation- hormonal contraceptives contain P or P + E -> negative feedback reduces FSH and LH
- prevent fertilization- barrier methods prevent sperm entry, P thickens cervical mucus (sperm cant get past it), copper blocks sperm mitochondria
- prevent implantation- hormonal contraceptives disrupt endometrium, copper blocks attachment
301
hydrophobic
lipophilic
302
which of the following will stimulate the release of the hormone insulin
- low plasma glucose
- *ACh binding to muscrarinic ACh receptors on beta cells of the pancreas- parasympathetic activity (rest and digest) after you eat a meal will increase insulin
- cortisol secretion from the ad-renal cortex
303
is the posterior pituitary gland protected by the blood brain barrier
- peptide hormones are blocked by blood brain barrier
| - therefore no
304
As blood flows from the aorta to capillary beds...
- Total cross-sectional area of the vasculature increases.
- Hydrostatic pressure DOES NOT increase slightly as blood enters arterioles.
- Velocity DOES NOT remains fairly constant.
BIO 203
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