1
Q
what are the three parts of a cell?
A
nucleus, cytoplasm, plasma membrane
2
Q
what is the nucleus?
A
control centre of the cell, contains DNA
3
Q
what is DNA? (deoxyribonucleic acid)
A
genetic code
4
Q
what is mRNA? (messenger ribonucleic acid)
A
produced from DNA blueprint, directs the production of proteins
5
Q
what are proteins?
A
carry out biological functions
6
Q
what are ribosomes? what are the two types?
A
needed for protein synthesis, free and membrane-bound
7
Q
what are free ribosomes?
A
ribosomes suspended in the cytosol
8
Q
what are membrane-bound ribosomes?
A
bound to endoplasmic reticulum
9
Q
what is cytoplasm?
A
consists of organelles, cytosol and inclusions
10
Q
what is the endoplasmic reticulum? what are the two types of ER?
A
extensive network of membranes joining the nucleus, rough ER and smooth ER
11
Q
what is rough ER?
A
covered in ribosomes. makes proteins, acts as a membrane factory
12
Q
what is smooth ER?
A
has specialised functions in particular cells
13
Q
examples of organelles?
A
endoplasmic reticulum, golgi apparatus, lysosomes, peroxisomes, mitochondria
14
Q
what is the golgi apparatus?
A
series of curved sacs, accepts transport vesicles from the ER for further processing
15
Q
what are lysosomes and peroxisomes?
A
membrane bound vesicles containing enzymes, bud off from the ER or golgi apparatus
16
Q
what do lysosomes do?
A
break down organic material inside the cell
17
Q
what do peroxisomes do?
A
degrade toxic molecules inside the cell
18
Q
what is the mitochondria?
A
the power plant of the cell, carries out aerobic cellular respiration
19
Q
what is aerobic cellular respiration?
A
nutrients in food converted to co2 and h20, and released energy is stored as ATP
20
Q
what is ATP (adenosine triphosphate)?
A
batteries inside the cell
21
Q
how do we use ATP?
A
synthesis of new compounds, transport of molecules across membranes, mechanical work
22
Q
what is the 1st step of protein synthesis?
A
protein-containing vesicles pinch off the rough ER, migrate to fuse with membranes of the golgi apparatus
23
Q
what is the 2nd step of protein synthesis?
A
proteins are modified within the golgi apparatus compartments
24
Q
what is the 3rd step of protein synthesis?
A
proteins are then packages within different vesicle types, depending on destination
25
what are the functions of the plasma membrane?
forms a mechanical barrier, selective permeability, electrochemical gradient, communication and cell signalling
26
what is the plasma membrane made up of?
a double layer of phospholipids with embedded proteins
27
explain the phospholipid bilayer.
two layers of phospholipids, the head faces toward the ECF and ICF while the tails are sandwiched in the middle
28
why can molecules transport across the plasma membrane?
it is selectively permeable
29
which molecules can pass across the plasma membrane?
penetrating molecules (gases, water, ethanol) and non penetrating molecules (ions, glucose, proteins)
30
transport across the plasma membrane can be...
passive or active
31
what is passive transport?
does not require cellular energy, moves down the concentration gradient (high to low)
32
what is active transport?
requires cellular energy, moves against the concentration gradient (low to high)
33
what are the types of passive transport?
simple diffusion, facilitated diffusion, osmosis
34
what are the types of active transport?
primary active transport, secondary active transport, vesicular transport
35
what is diffusion?
movement of molecules from high concentration to low concentration, down the concentration gradient
36
what is simple diffusion?
penetrating solutes diffuse through the plasma membrane unaided
37
what is facilitated diffusion? what are carriers and channels?
non penetrating solutes can only diffuse through the plasma membrane using carriers or channels. carriers = move, them channels = tunnels
38
what is osmosis?
movement of water across selectively permeable membrane from an area of low osmolarity to an area of high osmolarity, trying to even out the concentration
39
what is osmolarity?
the concentration of solutes in a solution
40
what is tonicity?
the effect a solution has on cell volume
41
what are the three types of tonicity?
isotonic solution, hypotonic solution, hypertonic solution
42
what is a isotonic solution?
solution has the same concentration (osmolarity) as the cells. no net movement of water. cell shape does not change
43
what is a hypotonic solution?
solution has lower concentration compared to cells. water will move into the cells. cells will swell.
44
what is a hypertonic solution?
higher concentration compared to cells. water moves out of the cells. cells will shrink.
45
what is primary active transport?
directly uses energy from breakdown of ATP. uses the Na+ -K+ pump
46
how does the Na+ -K+ pump work?
3 Na+ out, 2 K+ in
47
what is secondary active transport?
uses energy stored in ion concentration gradients, indirectly uses ATP via primary active transport. moves more than one molecule at a time. relies on primary active transport
48
what is vesicular transport?
transfer of materials between ECF and ICF within vesicles, requires ATP, exocytosis or endocytosis
49
what is exocytosis?
vesicular transport out of the cell
50
what is endocytosis?
vesicular transport into the cell
51
why do neurons/muscle cells change the membrane potential?
to create electrical signals, caused by a change in membrane permeability
52
what happens when the membrane potential is changed?
the number of open channels changes
53
channels can be:
always open (leakage) or gated (only opened when triggered)
54
what are the three types of gated channels?
chemically gated, voltage gated and mechanically gated
55
what are chemically gated channels?
open in response to binding of the appropriate neurotransmitter
56
what are voltage gated channels?
opens when the mebrane potential reaches a certain voltage
57
what signals are produced when the membrane potential is changed?
graded potentials and action potentials
58
what is a graded potential?
short lived changes in membrane potential, can be hyperpolarisation or depolarisation. triggered by a stimulus that opens gated ion channels.
59
example of graded potential:
a postsynaptic graded potential will occur when a neurotransmitter binds to a chemically gated ion on a post synaptic neuron
60
what is depolarisation?
decrease in membrane potential, inside of membrane becomes less negative
61
depolarisations often result from...
opening gated Na+ channels
62
what is hyperpolarisation?
increase in membrane potential, inside of membrane becomes more negative than resting membrane potential
63
hyperpolarisation can be from....
opening of K+ channels or anion channels
64
what happens when the membrane potential moves away from zero?
hyperpolarisation - probability of producing action potential decreases
65
what happens when the membrane potential moves toward zero?
depolarisation - probability of producing action potential increases
66
why are graded potentials 'graded'?
they can vary in amplitude. the magnitude of the response depends on the strength of the stimulus
67
graded potentials signal over:
short distances, become less strong moving away from the active area
68
why are graded potentials important?
provide the spark that starts an action potential
69
what is an action potential?
brief reversal of membrane potential, principal way neurons send signals, involves opening of voltage gated channels
70
where do action potentials occur?
only in muscle cells and axons of neurons
71
what is the difference between action potentials and graded potentials?
action potentials do not degrade over distance, graded potentials last only a short distance
72
what are the stages of an action potential?
1. resting state 2. depolarisation - Na+ comes into the cell 3. repolarisation K+ flows out of the cell 4. hyperpolarisation K+ continues to leave the cell
73
how do voltage gated Na+ channels work?
two gates, three states, cannot be restimulated when inactivated
74
what are the two gates of an Na+ channel?
activation gate and inactivation gate
75
what are the three states of an Na+ channel?
closed: no na+ enters the cell, opened: by depolarisation, allows Na+ to enter, inactivated: channels automatically blocked by inactivation gates soon after they open
76
how do voltage gated K+ channels work?
one gate, two states
77
what are the two states of K+ channels?
closed: resting state, no K+ exits the cell, opened: by depolarisation, after a delay, allows K+ to exit the cell
78
why is threshold critical in action potentials?
if threshold isn't reached, action potential will not occur
79
how does a neuron reset ion concentrations back to normal after an action potential?
the Na+ -K+ pump
80
how does an action potential propagate?
Na+ influx through channels in one membrane area causes local currents that cause opening of voltage gated Na+ channels in adjacent membrane areas
81
what prevents an action potential from moving backwards?
inactivation gates - the area behind an AP is repolarising, Na+ channels are closed but inactive so cannot respond to changes in voltage
82
what is the refractory period?
time in which a region of a neuron cannot trigger another action potential
83
what is an absolute refractory period?
the time from opening of na+ channels until resetting of the channels. inactivation gates open back up to reset
84
what is a relative refractory period?
time in which a region of a neuron cannot trigger another action potential. most na+ channels are resting, some k+ channels are still open. action potential requires a stronger stimulus to reach threshold
85
why are refractory periods important?
they ensure action potentials only spread in one direction
86
how do neurons communicate with each other?
through synapses
87
what is a synapse?
junction that allows information to transfer from one cell to another
88
89
where do synapses occur?
between two neurons: a presynaptic neuron and a postsynaptic neuron or between a neuron and an effector cell
90
what are the two types of synapses?
chemical and electrical
91
how does a chemical synapse work?
an electrical signal (AP) is converted to a chemical signal (neurotransmitter) and then back to an electrical signal (GP)
92
common neurotransmitters?
acetylcholine, dopamine, norepinephrine, epinephrine, serotonin, glutamate, GABA
93
neurotransmitters...
vary from synapse to synapse, same neurotransmitter is always released at a particular synapse
94
the binding of a neurotransmitter to a post-synaptic receptor will..
cause graded potentials
95
graded potentials can either be:
EPSP or IPSP
96
what is EPSP (excitatory postsynaptic potentials)
causes depolarisation, cation channels open, brings membrane closer to threshold
97
what is IPSP (inhibitory postsynaptic potentials)
causes hyperpolarisation, opens channels, membrane moves further away from threshold
98
why does EPSP cause depolarisation
movement of na+ and k+, more of na+ into the cell
99
why does IPSP cause hyperpolarisation
causes either k+ to leave or CL to enter
100
what is summation?
the addition of all EPSP and IPSP that a neuron receives, determines if an AP will occur
101
what are the two types of summation?
temporal and spatial
102
what happens when EPSPs are too far?
no AP, they wont add together
103
what is temporal summation?
a presynaptic neuron has action potentials in close succession, first AP produces EPSP and before it can dissipate another EPSP is triggered
104
what is spatial summation?
two or more presynaptic neurons simultaneously have APs, EPSPs generated at different locations on post-synaptic neurons
105
EPSPs and IPSPs can also...
cancel each other out
106
the autonomic nervous system..
maintains homeostasis, involuntary actions, targets organs in the thoracic and abdominopelvic cavities
107
what are the two divisions of the ANS?
sympathetic and parasympathetic
108
what is the sympathetic nervous system
fight or flight
109
what is the parasympathetic nervous system
rest and repose
110
many organs are
innervated by both divisions, have opposite effects
111
the ANS has a...
two motor neuron chain that synapses at autonomic ganglion in PNS
112
the somatic nervous system
has one motor neuron
113
what are preganglionic neurons?
cell bodies in the CNS, axons are called preganglionic fibres
114
what are ganglionic neurons?
cell bodies in autonomic ganglia, axons are called postganglionic fibres
115
preganglionic neurons synapse with:
ganglionic neurons
116
where are preganglionic neurons (sympathetic)?
cell bodies in lateral horn of the spinal cord
117
where are preganglionic fibres (sympathetic)?
leave the ventral roots of spinal cord, synapse at ganglia close to spinal cord, pre = short, post = long
118
three groups of ganglia?
sympathetic chain ganglia, collateral ganglia and adrenal medullae
119
what does the adrenal medullae doe?
supplements sympathetic NS, large quantities of epinephrine and norephineprhine into the blood
120
where are preganglionic neurons located (para)?
cell bodies in brain stem and sacral segment of spinal cord, synapse with ganglionic neurons close to or within target organs
121
how much outflow does the vagus nerve provide?
75% of all parasympathetic outflow
122
all ANS preganglionic and parasympathetic postganglionic fibres release...-
acetylcholine
123
what do sympathetic postganglionic fibres release?
most release norepinephrine, some acetylcholine
124
what cells have cholinergic receptors?
cells that respond to acetylcholine
125
what are the two types of cholinergic receptors?
nicotinic (all ganglionic neurons) and muscarinic (all parasympathetic target organs)
126
what are adrenergenic receptors?
bind epinephrine and norepinephrine with different affinities, found on sympathetic target organs, alpha and beta receptor types
127
Strokes:
- Damages to areas of primary motor cortex paralyses muscles controlled by those areas
- Stroke (or CVA) occurs when blood supply is blocked and neuron' s die
- TIAs are 'mini-strokes' (reversible)
- Paralysis occurs on opposite side of body from damage
- Gait re-training for rehab - neuroplasticity or 're-routing the brain'
128
Nervous System Divided Into 2 Major Anatomical Divisions:
129
Neurons - Excitable Cells That Transmit Electrical Signals:
- For communication via synapses
- Basic functional unit of the nervous system
130
Neuroglia:
- Supporting cells
- More numerous than neurons
- Support and insulate
131
Basic Structure of a Neuron:
- Cell body
- Processes: axons and dendrites
- Axon hillock
- Axon terminals
132
Grey Matter & White Matter in Brain Vs Spinal Cord:
133
White matter:
Predominated by axons/fibres that are myelinated
134
Grey Matter:
Predominated by cell bodies (soma) and dendrites
135
The Brain:
- Most complex organ in human body
- ~1.4kg; 100 billion neuron's
- Human brain has the largest ratio to body size of all mammals (EQ measures)
136
Landmarks of The Cerebrum:
- L & R hemispheres are separated by the longitudinal fissure
- The central sulcus separates the frontal and parietal lobes (pre-central gyris - site of primary motor cortex; and post-central gyrus - site of primary sensory cortex)
137
Divisions of The Brain - Cerebrum:
- Paired cerebral hemispheres
- Sulci (depressions) and gyri (ridges)
- Grey matter found superficially, white matter is deep
- Lobes: frontal, parietal, temporal, occipital
- Functions incl: sensation, conscious thought and intellect, memory, complex movement
138
Frontal lobe:
The lobe at the front of the brain associated with voluntary movement, speech, and impulsive behaviour. Includes primary motor area
139
Parietal lobe:
A region of the cerebral cortex whose functions include processing information about touch. Includes primary somatosensory area (proprioception)
140
Temporal Lobe:
An area on each hemisphere of the cerebral cortex near the temples that is the primary receiving area for auditory information. Includes primary auditory cortex (hearing)
141
Occipital Lobe:
A region of the cerebral cortex that processes visual information. Includes primary visual cortex (seeing)
142
3 Regions of The Cerebral Hemisphere:
- Each hemisphere has 3 primary regions: cerebral cortex (outer grey matter), internal white matter, basal nuclei (grey matter located deep within the white matter)
- Each hemisphere receives and sends information from/to contralateral side of the body (note that there are some exceptions
143
The Cerebral Cortex Has 3 Types of Functional Areas:
- Motor areas: control voluntary movement
- Sensory areas: conscious awareness of sensation
- Association areas: multiple inputs and outputs
144
White Matter - 3 Types of Fibres:
- Association fibres: connect different parts of the same hemisphere
- Commissural fibres connect grey areas of two hemispheres: Corpus callosum (largest) and anterior/posterior fibres
- Projection fibres - vertical tracts that connect cerebral cortex with subcortical structures: sensory information enters and motor commands leave through these fibres
145
Basal Nuclei:
- Functional group of grey matter deep in the cerebrum, diencephalon and midbrain
- Receives input from entire cerebral cortex
- Involved in control of skeletal muscle, cognition, and emotion
146
Diencephalon: Thalamus:
- Many groups of nuclei that relay different types of sensory information,
'gatekeeper' to the cortex, involved in motor and limbic connections to the cortex
147
Diencephalon - Hypothalamus:
- Homeostasis, autonomic, emotions, body temp, food intake, thirst,
sleep-wake cycles; control of hormones
148
Diencephalon - Epithalamus:
- Pineal gland (melatonin), day/night cycles
149
Diencephalon Image:
150
The Brainstem: Midbrain (Mesencephalon):
- Contains nuclei for visual/auditory information & controls reflexes associated with these senses
151
The Brainstem: Pons:
- Ascending, descending and transverse (link to cerebellum) tracts, involved in control of respiration
152
The Brainstem: Medulla Oblongata:
- Most inferior, joins to spinal cord at foramen magnum of skull. Is the autonomic reflex centre: heart rate, respiratory rhythms, hiccup, vomit, swallowing, coughing
153
The Brainstem:
154
The Cerebellum: 'Little Brain':
- Second largest brain structure
- Cerebellar hemispheres connected by the vermis
- Folds termed folia
- Connected to the brainstem via the cerebellar peduncles
- Important role in equilibrium, balance, and coordination of movement (happens subconsciously)
155
Review of Diencephalon (3), Brain Stem (3), Cerebellum:
156
Spinal Cord:
- Cylindrical extension of medulla oblongata
- Enclosed in vertebral column (~42cm long)
- Provides two-way communication to and from brain and body
- Major reflex center: reflexes are initiated and completed at spinal cord
157
Features of The Spinal Cord:
- Ends at L1-L2 at the conus medullaris
- Filum terminale - anchor spinal cord
- Cauda Equina - spinal nerve root
158
Spinal Nerves Connect The Spinal Cord Via Roots:
- Dorsal Root - sensory
- Ventral root - Motor
- White matter - made of un-myelinated and myelinated fibres: ascending, descending, transvers
159
Meninges:
- Brain and spinal cord have coverings to protect them
- Dura mater (superficial); arachnoid mater (middle), pia mater (deep)
- Meningitis - inflammation, serious threat to CNS
160
Meninges: Dura Mater:
- Superficial layer
- 2 layers
- outer layer fused to periosteum (for cranial meninges)
- Dural venous sinuses between the two layers (collect venous blood)
- Dural folds (septa)
161
Meninges: Arachnoid Mater:
- Middle layer
- Trabeculae attach to pia
- CSF in subarachnoid space
162
Meninges: Pia Mater (Deep):
- Rich with small blood vessels
- Follows contours of gyri and sulci
163
Spinal Cord Also Covered by Meninges:
- Dura mater, arachnoid mater, pia mater (continuous with cranial meninges)
- Epidural space surrounds the dura of the spinal cord
164
CSF:
CSF supports. nourishes, cushions brain and spinal cord ventricles:
- Lateral ventricles (x2, one in each hemisphere)
- 3rd ventricle (in diencephalon)
- 4th ventricle (between pons, medulla and cerebellum
The choroid plexus, found on roof of ventricles, produces CSF
165
What is the structure and function of the nucleus?:
This is the control center of the cell. It contains DNA, the genetic material found in every cell. It is surrounded by the nuclear envelope (two layers of membrane) where nuclear pores allow for movement of molecules. Inside the nucleus is DNA and mRNA: is the site of transcription.
166
What is the structure and role of mRNA?:
This is a single stranded complementary molecule that is composed of complementary nucleotides from a unwound DNA template strand. It is formed in the nucleus, and travels out of the nucleus via nuclear pore into the cytosol after introns are spliced out. There it is read by and translated by a ribosome and tRNA to form a polypeptide (composed of amino acids). mRNA functions to facilitate protein synthesis by acting as a replica of a DNA strand.
167
What is the function of a ribosome?:
Creates proteins by reading mRNA strands.
168
What are the two types of ribosomes?:
Free ribosomes - suspended in the cytosol, and make proteins that will mostly function inside the cytosol.
Membrane-bound ribosomes - Bound ribosomes are attached to the rough endoplasmic reticulum. Membrane-bound ribosomes create proteins that mostly function in membranes e.g. in the cell's plasma membrane, or outside of the cell.
169
What is the cytoplasm composed of?:
Cytosol (fluid) and organelles.
170
What is the structure and function of the rough ER?:
This is an extensive network of membrane-enclosed tubules and sacs (cisternae) in eukaryotic cells. This structure is continuous with the smooth ER and nucleus. It is covered in ribosomes that are embedded in the membrane. The rough ER acts as a membrane factory, in which it packages and transports the proteins that it's ribosomes make to the Golgi Apparatus in transport vesicles.
171
What is the structure and function of the smooth ER?:
Consists of smooth, branched, tube-like interconnected structures. Has specialised functions in particular cells. For example - detoxification (liver and kidneys), making steroid-based hormones (testes), releasing calcium for muscle contraction (skeletal and cardiac muscle). Mainly involved in lipid synthesis, metabolic processes, detoxification, and calcium storage.
172
What is the structure and function of the Golgi Apparatus?:
Sorting and distribution center. This structure is composed of a series of curved sacs made of membrane with fluid inside. It functions by accepting transport vesicles from the ER for further processing. Transport vesicle attaches to Golgi apparatus whereby proteins can then be modified, sorted and 'shipped' to their final destination outside the cell, to the various membranes or to the organelles. Proteins are repackaged into transport vesicles and moved to needed locations.
173
What are transport vesicles?:
Packages of plasma membrane containing fluid and proteins.
174
What are lysosomes?:
These are membrane bound vesicles containing enzymes which are released to break down organic material inside the cells e.g. bacteria, old organelles. They bud off the Golgi or ER.
175
What are peroxisomes?:
These are membrane bound vesicles containing enzymes which are released to break down toxic substances inside the cells e.g. alcohol. They bud off the
176
What are transport vesicles?
Packages of plasma membrane containing fluid and proteins
177
What are lysosomes?
These are membrane bound vesicles containing enzymes which are released to break down organic material inside the cells e.g. bacteria, old organelles. They bud off the Golgi or ER.
178
What are peroxisomes?
These are membrane bound vesicles containing enzymes which are released to break down toxic substances inside the cells e.g. alcohol. They bud off the Golgi or ER.
179
What is the structure and function of a mitochondria?
Double membrane, oval shaped organelle. Carries out aerobic (using oxygen) cellular respiration to create ATP. Nutrients in food is converted to CO2 and H2O as byproducts, and the energy that is produced here is released and stored, called ATP.
180
What are the 4 main tissue types?
Epithelia (epithelial tissue cells), Connective tissue (bones, cartilage, tendons, ligaments), Muscle (cardiac, smooth, skeletal) and neural tissue.
181
What are the 3 body planes?
sagittal (divided into left and right), frontal/coronal (divided into anterior and posterior), transverse (divided into superior and inferior).
182
What is ATP and what is it used for?
Supplies energy to a reaction by breaking and converting from ATP (three chain of phosphates) to ADP (two chain of phosphate - adenosine diphosphate) and a phosphate group. Synthesis of new compounds (e.g. proteins) Transport of molecules across membranes Mechanical work (e.g. contraction of muscle cells)
183
What is the function of the plasma membrane?
Forms a mechanical barrier (ICF vs ECF). Selective permeability - determines which molecules can move into/out of cell. Electrochemical gradient - important for neural and muscle function. Communication and cell signaling - receiving and interpreting messages from other cells
184
What is the structure of the plasma membrane?
The plasma membrane has a double layer of phospholipids with embedded proteins 'phospholipid bilayer'. Phospholipids have a ''head'' and two ''tails''. The phosphate head is hydrophilic and the fatty-acid tails are hydrophobic. The hydrophilic heads (negatively charged, polar) face the watery environment of the ECF and ICF. The hydrophobic tails (non-polar) are sandwiched in the middle of the membrane, away from water.
185
What are the factors influencing whether a molecule can pass through the cell membrane?
size, polarity, concentration gradient
186
What is the difference between active and passive transport?
Passive transport does not require energy - molecules only move from high con to low con (down gradient). Active transport requires cellular energy (ATP) - molecules move from low con to high con (against gradient).
187
Name the 3 types of passive transport.
simple diffusion, facilitated diffusion, osmosis
188
What is simple diffusion?
Penetrating solutes can diffuse through the plasma membrane unaided e.g. movement of oxygen gas between blood and air.
189
What is osmosis?
diffusion of water across a selectively permeable membrane from an area of low osmolarity to an area of high osmolarity. *Osmolarity: the number of solute particles in the solution (not relative to water particles like concentration, only measuring solute).
190
What is facilitated diffusion?
Diffusion of non-penetrating molecules across the membrane using carriers or channels. Carriers interact with the molecule and move them to the other side e.g. glucose transporters. Channels act like tunnels/pores through the membrane e.g. ion channels in neurons.
191
What are the 3 types of active transport?
Primary active transport Secondary active transport Vesicular transport (endocytosis & exocytosis)
192
What is primary active transport?
Sodium potassium pump - uses ATP to pump Na and K against the concentration gradient.
193
What is secondary active transport?
. One molecule, usually an ion, will move down the concentration gradient (passive), providing the energy source. The other molecule will 'hitch a ride' at the same time, so that it can move against its own concentration gradient. Carriers proteins that bind both the driving ion and the molecule to be transported carry these molecules across the membrane using the potential energy stored in an ion gradient. It involves a "cotransporter" protein that uses the energy from one molecule moving down its concentration gradient (usually sodium or hydrogen) to drive another molecule against its concentration gradient.
194
What is vesicular transport?
Vesicular transport refers to the transport of materials (that are too large to move with carriers or channels) between ECF and ICF within vesicles - fluid filled sacks enclosed by membrane. This requires energy from ATP. Exocytosis - vesicular transport out of the cell Endocytosis - vesicular transport into the cel
195
What is tonicity?
the effect that a solution has on cell size and shape due to water movement and osmolarity differences (osmosis).
196
What happens to cells in an isotonic solution?
Solution has the same osmolarity of nonpenetrating solutes compared to the cells. This means there will be no net movement of water, and that the cell's shape does not change.
197
What happens to cells in a hypotonic solution?
Lower osmolarity of nonpenetrating solutes in the solution compared to the cells. Water moves into the cells causing the cells to swell.
198
What happens to cells in a hypertonic solution?
Higher osmolarity of nonpenetrating solutes in the solution compared to the cells. Water will move out of the cell causing the cell to shrink/wrinkle.
199
What are the divisions of the PNS?
Afferent and efferent. Efferent divides into somatic and autonomic. Autonomic divides into sympathetic and the parasympathetic.
200
What is the nervous system composed of?
neurons and neuroglia (supporting cells).
201
What are the four types of neuroglia in the CNS?
astrocytes, oligodendrocytes, microglia, ependymal cells
202
What are the two types of neuroglia in the PNS?
Schwann cells and satellite cells
203
What are bundles of nerves called?
PNS: nerves CNS: tracts
204
What are clusters of neuronal cell bodies called?
PNS: ganglia CNS: nuclei
205
What is resting membrane potential?
Resting membrane potential is the stable, negative electrical charge difference (-70 mV) maintained across a cell membrane when it is not actively sending signals. it is maintained using leakage channels and the sodium potassium pump. It is a balance between concentration gradient, ion permeability and electrical gradient.
206
Are there more sodium or potassium leakage channels?
Potassium.
207
Where does potassium naturally move?
Out of the cell.
208
Where does Na+ naturally move?
Into the cell.
209
What are the two types of channels?
Leakage (always open/pore) or gated (only opened when triggered)
210
What are the 3 types of gated channels?
chemically gated, voltage gated, mechanically gated
211
Visceral Anatomy:
- Visceral organs such as the heart, lungs, GIT & internal reproductive organs - The heart is in the pericardial cavity which sit in the mediastinum
212
Cardiovascular System Composed of:
- Heart - Arteries - Veins - Blood
213
Cardiovascular System 2 Main Circuits:
- Pulmonary - Systemic
214
Structures of The Cardiovascular System:
1. Blood - made up of plasma and cells (fluid connective tissue) 2. Heart - 4 chambered muscular pump - muscle layer known as myocardium 3. Blood vessels - transports blood: - arteries - carry blood away from heart (usually oxygen rich) - Capillaries - allows exchanges of gases, nutrients between blood and tissues - Veins - return blood to heart (usually oxygen poor)
215
Anatomy of The Heart (Anterior):
- 4 Chambers: 2 atria & 2 ventricles - 2 large arteries that leave the ventricles: ascending aorta & pulmonary trunk - 2 large veins that return blood to right atrium: inferior vena cava and superior vena cava - 4 pulmonary veins return blood to left atrium: 2 right pulmonary veins and 2 left pulmonary veins
216
Heart Valves:
2 Atrioventricular valves - Right AV valve - Tricuspid - Left AV valve - Bicuspid - Tethered by Chordae tendineae which are attached to heart muscle by Papillary myscle 2 Sets of Semi-Lunar Valves - Pulmonary Valve - Aortic valve
217
Heart Valves (a):
A) AV valves open; atrial pressure greater than ventricular pressure
218
Heart Valves (b):
B) AV valves closed; atrial pressure less than ventricular pressure - The shutting of the AV valves creates a heart sound - 1st heart sound - This happens when the ventricles contract. Contraction = systole - This first heart sound = ventricular systole
219
Heart Valves (c):
C) - The shutting of the semilunar valves creates a heart sound - 2nd heart sound - This happens when all chambers relax. Relaxation = diastole - The second heart sound = diastole Clinical Link - Valve replacement w/ mechanical/animal/cadaver - Incompetent valves -> backflow - Valve stenosis -> valves hard to open so more force needed
220
Blood Flow Through Heart:
Blood travels through right side of heart & pulmonary circuit first - IVC + SVC -> right atria -> R AV valve -> right ventricle -> pulmonary valve -> pulmonary trunk -> lung Then blood travels through the left side of the heart & systemic system - Pulmonary veins -> left atria -> L AV valve -> left ventricle -> aortic valve -> systemic system
221
Left Ventricle:
- Wall of left ventricle much thicker as it needs to push blood all the way around the body - Hypertrophy of left ventricle caused by obesity etc
222
4 functions of skeletal muscle:
produce movement, maintain posture, stabilize joints, generate heat
223
Structural differences between parallel and pennate muscles:
In parallel muscles the fascicles lie parallel to the muscles line of action. In pennate muscles, the fascicles lie at an angle relative to the line of action.
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Functional differences between parallel and pennate muscles:
Pennate muscles have short, angled fibres which produce a smaller range of motion. Parallel muscles have long muscle fascicles which produce more muscles shortening and a larger range of motion at the joint.
225
4 quadriceps muscles:
rectus femoris, vastus lateralis, vastus medialis, vastus intermedius
226
3 muscles that comprise Achilles tendon:
Soleus, medial and later gastrocnemius, plantaris
227
Graded potentials:
incoming signals operating over short distances
228
Action potentials:
long distance signals of axons
229
Ganglia:
clusters of cell bodies in the PNS
230
Parasympathetic preganglionic fibres release...:
acetylcholine
231
Sympathetic preganglionic fibres release...:
acetylcholine
232
Sympathetic postganglionic fibers release...:
noradrenaline
233
Excitatory post synaptic potential:
short distance hyperpolarisation
234
When membrane potential DECREASES, action potential...:
increases
235
When membrane potential INCREASES, action potential...:
decreases
236
Purpose of hyperpolarisation:
to inhibit constant contraction by reducing the probability of producing action potential
237
Golgi tendon reflex:
produces muscle relaxation and lengthening in response to muscle tension
238
Sulci:
shallow grooves in brain
239
Gyri:
elevated ridges in brain
240
Pons:
bridge between the brain stem and the cerebellum, where all info entering or exiting the cerebellum is collected
241
central sulcus:
separates perietal lobe from frontal
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nerve plexus:
complicated interlacing of ventral rami
243
ventral rami:
spinal nerves - supply limbs and anterior trunk
244
neuroglia:
supporting cells
245
Bundles of axons in PNS:
nerves
246
Bundles of axons in CNS:
tracts
247
Clusters of neuronal cell bodies in CNS:
Nuclei
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resting membrane potential =:
-50 mV to -100 mV
249
Resting membrane potential depends on...:
- concentration gradient - electrical gradient - permeability for each ion
250
Excitable cells:
use resting membrane potential to do work by changing permeability of plasma membrane to Na+ & K+
251
Interneurons:
connect sensory and motor neurons (mostly CNS)
252
ICF and ECF are electrically neutral. Voltage is only present...:
at membrane surface
253
Plasma membrane has more leakage channels for...:
K+ than Na+
254
Excitatory post-synaptic potentials (EPSP):
cause DEPOLARISATION to bring the membrane closer to threshold
255
Inhibitory post-synaptic potentials (IPSP):
cause HYPERPOLARISATION to bring membrane further from threshold
256
Summation:
addition of all EPSP and IPSP that neuron receives, determines whether action potential occurs or not
257
Temporal summation:
action potential of presynaptic neuron occur within close succession
258
Spatial summation:
action potential of 2+ presynaptic neurons occur same time but at different location on postsynaptic neuron
259
Motor neuron chain (somatic):
one long, direct neuron from efferent innervation to somatic effectors (skeletal muscle)
260
Motor neuron chain (autonomic):
two motor neurons that synapse at an autonomic ganglion
261
preganglionic neuron:
are cells bodies within the CNS (brains stem and spinal cords)
262
meninges:
three protective membranes that surround the brain and spinal cord
263
3 meninges of brain include::
- dura - arachnoid - pia mater
264
Ganglia in parasympathetic:
long preganglia, short postganglia
265
Ganglia in sympathetic:
short preganglia, long postganglia
266
Site of origin of ganglia in parasympathetic division:
brain stem and sacrum (inferior and superior)
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Site of origin of ganglia in sympathetic division:
T1 to L1 vertebrae
268
Ganglia for sensory neurons lie...:
OUTSIDE of the CNS
269
Ganglia for motor neurons lie...:
WITHIN CNS
270
31 spinal nerves::
8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
271
Dorsal root:
sensory (afferent)
272
Ventral root:
motor (efferent)
273
Dorsal rami:
provide sensory + motor info to skin & back muscles
274
Ventral rami:
provide sensory + motor info to rest of trunk & limbs
275
Plexuses:
formed by ventral rami, overlapping spinal nerves so that each muscle receives input from 1+ spinal nerve
276
Plexus types:
- cervical - brachial (neck, shoulder arm) - lumbar (psoas muscle/anterior thigh) - Sacral (bum, lower limb, pelvis)
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Brachial plexus:
- C5 to T1 roots - 3 trunks - 3 cords - 5 peripheral nerves
278
Plexuses
formed by ventral rami, overlapping spinal nerves so that each muscle receives input from 1+ spinal nerve
279
Plexus types
- cervical
- brachial (neck, shoulder arm)
- lumbar (psoas muscle/anterior thigh)
- Sacral (bum, lower limb, pelvis)
280
Brachial plexus
- C5 to T1 roots
- 3 trunks
- 3 cords
- 5 peripheral nerves
281
5 peripheral nerves of brachial plexus
-Musculocutaneous
- Axillary
- Radial
- Medial
- Ulnar
282
12 pairs of cranial nerves include
- sensory, motor or mixed
- CNI: cerebrum
- CNII: diencephalon
- CNIII-XII: brainstem
283
Reflex arc consists of
1. receptor
2. sensory neuron
3. integration centre (interneuron)
4. motor neuron
5. effector
284
Monosynaptic reflexes
sensory and motor neurons communicate directly without the need of an interneuron
285
Polysynaptic reflexes
sensory and motor neurons communicate through an interneuron between them, slower
BIOM1060 midsemester
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