1
Q
How do the nervous and endocrine system work together
A
They control the actions in your body and adjust and regulate things to keep the internal environment within safe limits.
2
Q
What are the two ways responses can be made by the body?
A
- sending electrochemcial messages to and from the brain
- chemical messengers (hormones) carried by the blood
3
Q
What are the two main devisions in the nervous system?
A
- Central nervous system (CNS)
- Peripheral nervous system (PNS)
4
Q
What is the Central Nervous System (CNS) made up of?
A
It is made up of nerves of the brain and spinal cord
5
Q
What is the role of the CNS?
A
coordinate messages that are incoming and outgoing
6
Q
What is the role of Peripheral Nervous System (PNR)?
A
they have nerves that carry messages between the organs of the body and the central nervous system.
7
Q
Two types of nerves in PNS
A
- Somatic nerves
- Autonomic nerves
8
Q
Whats the difference between somatic nerves and autonomic nerves?
A
Somatic nerves –> voluntary
Autonomic nerves –> involuntary
9
Q
What do the somatic nerves control?
A
They control the skeletal muscles, bones and skin
10
Q
Two sub-types of somatic nerves?
A
- sensory somatic nerves
- motor somatic nerves
11
Q
Sensory Somatic Nerves
A
send information about the environment to the CNS (afferent–> sensory input)
12
Q
Motor Somatic Nervers
A
initiate an appropriate response (efferent –> sensory output)
13
Q
Two sub-types of autonomic nerves
A
- sympathetic autonomic nerves
- parasympathetic autonomic nerves
14
Q
Sympathetic Autonomic Nerves
A
prepares the body for stress (arousing)
- increases heart rate, blood flow, and the release of glucose
- pupils dilate, relaxes bladder sphincter, decreases peristalsis
15
Q
Parasympathetic Autonomic Nerves
A
return the body to normal after stress (calming)
16
Q
Two types of cells found in nervous system
A
- Glial Cell
- Neurons
17
Q
Glial Cell
A
non-conducting cells important for structural support and metabolism of the nerve cells
18
Q
Neurons
A
functional units that are categorised into three groups
19
Q
What are the three groups that neurons are categorised under
A
– sensory neurons
- interneurons
- motor neurons
20
Q
Sensory Neurons (afferent neurons)
A
sense and relay information to the CNS.
21
Q
Where are sensory neurons located?
A
located in clusters outside the spinal cord
22
Q
Examples of sensory neurons
A
chemoreceptors, thermoreceptors, photoreceptors
23
Q
Interneurons
A
link neurons together which enables the connections between sensory or motor neurons and the CNS
24
Q
Where are motor neurons found?
A
mostly found in the brain and spinal cord
25
What do the brain and spinal cord make up?
the central nodes of the neural circuits
26
Motor neurons
relay information to the effectors such as muscles, organs, and glands (they produce responses)
27
What are the three main things that nerve cells contain?
- Dendrites
- Axons
- Myelin Sheath
28
Dendrites
receive information, from sensory receptors or other neurons, and conduct impulses toward the cell body
29
Axons
conduct.messages away from the cell body to other neurons or to effectors
30
Myelin Sheath
white coat of fatty protein that covers many axons, a cutting like insulation for neurons
31
What are axons an extension of?
They are an extension of the cytoplasm
32
How are most nerves made?
Most nerves are made of many neurons held together
33
Schwann Cells
a type of glial cells. that forms myelin
34
nodes of Ranvier
nodes between the sections of myelin
35
How to speed up nerve impulses?
nerve impulses jump from node to node to speed up nerve impulses.
36
What gives the fastest conductive speed?
a small diameter axon with myelin can give the fastest conductive speed.
37
Neurilemma
thin membrane (sheath) that surrounds the axons of nerve cells found in the PNS
38
What does neurilemma do?
it promotes regeneration of damaged axons
Eg: helps a cut connect again (this is part of the PNS)
39
Whats a difference between PNS and CNS concerning regeneration?
PNS --> regenerate; temporary damage
CNS --> can't regenerate; permanent damage
40
Describe the Reflex Arc Process
Eg: you touch something hot
Path the Impulse Travels:
sensory neuron --> interneuron (in spinal cord CNS) --> motor neuron --> muscle moves so you can pull your hand away
41
What three neurons are involved?
- sensory neuron
- interneuron
- motor neuron
42
Why exactly does the reflex arc minimize injury
The reflex arc minimizes injury because it allows the impulse to be sent to a motor neuron in the spinal cord and a response generated before the signal reaches the brain.
43
At what rate does the reflex arc occur?
Happens in les than a second, and your hand will pull away even before the message reaches the brain
44
What are the five components of the reflex arc?
1. (pain) receptor
2. sensory neuron
3. interneuron / relay neuron
4. motor neuron
5. effector
45
When is the signal sent to the brain in the reflex arc?
Once the message is received in the interneuron, the message also goes to the brain at the same time
46
What does sending the signal to the brain do in the reflex arc?
It helps you eventually realise what's happening.
47
What does the effector do in the reflex arc?
It contracts the muscle cells.
48
How do nerve impulses move around the body?
Nerves send messages when charged ions (like Na⁺ and K⁺) move in and out of the neuron (or across the membrane) through ion channels, creating an electrical signal called a nerve impulse or action potential. Action potential then travels down the axon to the next neuron.
49
Resting potential
-70 mV
inside a nerve fiber
50
What does mV stand for?
millivolts
51
Action Potential
+ 40 mV
- brief
- travels down the nerve fibre
52
When is the action potential reached?
when the nerve becomes excited and potential reverses
53
What's another word for nerve fibre?
axon
54
How do nerves become charged?
nerves normally contain many positive and negative ions on the inside and outside of the cell
55
How is an electrochemical event made?
It is caused by unequal concentration of positive ions across the membrane
56
Where is potassium found in the context of the electrochemical impulse?
Potassium (K+) ions normally found in high concentrations inside the cell.
57
Where is sodium found in the context of the electrochemical impulse?
Sodium (Na+) ions normally found in high concentrations outside of the cell.
58
How are the concentrations of potassium and sodium maintained in and out of the cell?
Na+/K+ pump that ensures that K+ concentration inside and the Na+ concentration on the outisde.
59
What makes a polarised membrane
Greater number of positive ions are located outside of cell, causing the membrane to be electrically charged
60
How is a polarised membrane made?
K+ leaks slowly out of the membrane faster than Na+ leaks in, leaving the outside a bit more positive because of these leaky ion channels
61
How do charge look in a polarized membrane?
It is at a resting potential- a charge of -70 mV
more negative charge inside compared to the more positive charge outside , due to extra K+ outside
62
What happens during excitation?
the nerve cell membrane becomes a lot more permeable to sodium than potasisum
63
What triggers excitation?
a charge disturbance (impulse) approaches
64
What must the charge do to cause special sodium gates to open?
it must meet a minimum threshold
65
Depolarisation
Sodium rushes in, attracted by the internal negative charges and by diffusion along its gradient
66
What does depolarisation start?
It starts action potential
67
Repolarisation
happens when special potassium gates are opened in response to this strong positive charge inside and K+ leaves by diffusion in order to restore resting potential of cell.
68
What does repolarisation end?
It ends action potential
69
Hyperpolarisation
K+ channels open a but longer than the Na+ channels, meaning that the cell goes a bit more negative than normal inside the axon
70
What's another name for hyperpolarisation?
overshoot
71
Where is the Sodium Potassium Pump located
in the membrane
72
What makes the sodium potassium pump work?
ATP makes the pump to work
73
What does the sodium-potassium pump do?
It restores the resting condition of the membrane by moving the inside sodium back out, ad outside the potassium back in, to what it was like before (-70 mV).
74
Why is the sodium-potassium pump necessary?
It compensates for the "leaks" and is thus always working
75
Whats the rate at which this pump works
It moves 3 Na⁺ ions out of the cell for every 2 K⁺ ions it moves into the cell. It is to help maintain the inside of the neuron as more negative than the outside.
76
When is a nervous response produced?
It is produced when a potential stimulus is above a critical value.
77
All or none concept
Nerves either fire maximally or not at all
78
What is true about nerve impulses along the axon
They are always of identical amplitude and speed along the axon.
79
What is necessary to distinguish between weak or strong stimulus?
A greater impulses is required to distinguish between the two
(impulses pack closer together)
80
What's the another way for your brain to determine the intensity of a stimulus?
have different nerve cells, in the same nerve fibre, with different threshold levels for a particular stimulus
81
What are the two ways of determining the intensity of a stimulus?
- a greater frequency of impulses
- different nerve cells with different threshold levels for a particular stimulus
82
Synapses
The small spaces between neuron, or between neurons and effectors
83
Which path does an impulse usually follow?
Moves along an axon to the end plate where chemicals are released from vesicles. They diffuse across the gap and activate the dendrites of the postsynaptic neurons
presynaptic neuron --> neurotransmitters released from vesicles --> diffuse through synapse --> dendrites of postsynaptic neurons are activated through binding of neurotransmitters
84
What components are needed for the path of an impulse
- presynaptic neuron: releases neurotransmitters
- neurotransmitters
- postsynaptic neurons: detects neurotransmitters and responds
85
What is found in the postsynaptic neurons
many neurons can be typically found on the other side of synapse
86
Whats the disadvantage of synapse?
even though the space between neurons is small, it still causes a slight delay in messaging
87
What's the correlation between reflex arc and synapse?
Reflex arc is so fast because there are fewer synapse involved.
88
What is an example of a positive neurotransmitter?
accetylcholine
89
Where is accetylcholine released from?
It is released from a presynaptic membrane
90
What is the purpose of accetylcholine
It is a neurotransmitter on many postsynaptic neurons because it opens their sodium channels once it reaches the membrane of the postsynaptic neuron, making it becomes the presynaptic neuron for the next synapse.
91
What is the purpose of cholinesterase?
breaks down accetylcholine so the neuron can enter the recovery phase, stopping it from just keeping the sodium channels open.
92
Two Types of transmissions across a synapses and what do they result itn
- excitatory --> Na+ --> depolarisation
- inhibitory --> K+/Cl- --> hyperpolarisation
93
What do inhibitory transmitters do?
They make the postsynaptic membrane more permeable to potassium or chloride
94
What happens when inhibitory transmitters are used?
They would cause the cell to hyperpolarise, which is even harder to generate an action potential because the resting membrane is even more negative now
95
Whats another example of excitatory neurotransmitter?
glutamate
96
What's a typical example of inhibitory neurotransmitter?
GABA
97
Explain how excitatory and inhibitory neurotransmittors function to depolarise or hyperpolarise
Excitatory neurotransmitters → open Na⁺ channels →The inside becomes less negative
→ depolarise → neuron is more likely to fire
Inhibitory neurotransmitters → open Cl⁻ or K⁺ channels → The inside becomes more negative than resting potential →hyperpolarise → neuron is less likely to fire
98
Describe how neural pathways will give different results with
Cell A and B- excitatory neurotransmitters
Cell C- inhibitory neurotransmitter
Cell D- the cell that is being converged
Cell A/B --> neither neuron by itself is capable of causing sufficient depolarisation to generate an action potential in cell D
Cell A and B --> exceed threshold and action potential will result
Cell A, B, and C --> all three messages average and there will be no action potential
99
Why is it extremely important to have inhibitory neurotransmitters?
It allows your brain to prioritise information, by ignoring information that isn't important to the situation\
Eg: focus in class rather than focus on the feel of your clothes
100
How do the excitatory and inhibitory impulses work together when you bend your arm up
The biceps receive excitatory impulses, while your triceps get inhibitory impulses, so your muscles don't work against each other.
1. Your biceps must contract
So the motor neurons going to the biceps receive excitatory impulses.
Excitatory = opens Na⁺ channels → depolarises → action potential → muscle contracts.
2. Your triceps must relax
So the motor neurons going to the triceps receive inhibitory impulses.
Inhibitory = opens Cl⁻ or K⁺ channels → hyperpolarises → no action potential → muscle relaxes.
This prevents the triceps from pulling in the opposite direction.
101
What are meninges?
3-layer protective membrane that the brain is surrounded by
102
What do the meninges form?
They form the blood-brain barrier
103
What does the blood-brain barrier do?
They control what chemicals reach the brain
104
Where are 2 places cerebrospinal fluid is found?
- between the innermost and middle meninges of the brain
- through the central canal of the spinal cord
105
What 3 role do cerebrospinal fluid have?
- acts as a shock absorber
- carries nutrients to brain cells
- carries wastes from these cells to the blood
106
What are the 2 roles of spinal cord?
- It carries sensory nerve messages from receptors to the brain
- It relays motor nerve messages from the brain to muscles, organs, and glands
107
What are the 2 types of tissue found in the spinal cord?
- white matter
- grey matter
108
White Matter
composed of mylenated nerve fibres (or axons) from sensory and motor neurons
109
Grey Matter
composed of non-mylenated interneurons
110
What is the purpose of interneurons?
organised into nerve tracts that connect the spinal cord to the brain
111
What is the purpose of dorsal nerve tract?
It brings sensory information into the spinal cord
112
What is the purpose of ventral nerve tract?
It carries motor information away from the cord to the peripheral muscles, organs, and glands
113
How many parts is the brain divided into and what are these parts called?
- forebrain
- midbrain
- hindbrain
114
What are olfactory lobes used for and where are they found?
Paired olfactory lobes are used for smell and found in forebrains
115
What does the cerebrum have and what are their roles
They have 2 large hemispheres that act as major coordinating centre which stores sensory information and initiates voluntary motor activities
116
Where does speech, reasoning, memory, and personality reside?
in cerebrum
117
What is cerebral cortex?
It is the surface of the cerebrum
118
What does cerebral cortex contain?
It contains many folds that increase surface area
119
How the hemispheres in the cerebrum differ?
Right hemisphere --> associated with visual patterns or spatial awareness
Left hemisphere --> linked with verbal skills
120
What is the role of corpus callosum?
They are nerves that makes communication between hemispheres possible
121
What is found below the cerebrum
thalamus
122
What is found below the thalamus
hypothalamus
123
What unites the nervous system with the endocrine system?
The direct connection between the hypothalamus and pituitary gland
124
What role does the motor cortex play
stimulation of this cortex can trigger muscles in various parts of the body
125
Which part of the body has the most nerves
Places that have the most sensory information like face and fingers have the most nerves represented
126
How many lobes can cerebrum hemispheres be divided into?
four lobes
127
What are the four lobes in the cerebrum
- frontal lobe
- temporal lobe
- occipital lobe
- parietal lobe
128
What is the frontal lobe responsible for?
motor areas (movements), memory, inhibition of unsuitable behaviours
129
What is the temporal lobe responsible for?
hearing, advanced visual processing
130
What is the occipital lobe responsible for?
vision
131
What is the parietal lobe responsible for?
body senses (touch, temperature, pain and orientation)
132
What is the midbrain responsible for?
it acts as a relay centre for some eye and ear reflexes (automatic reflexes rather than complex thinking.)
- it is less developed area
133
Where is the hindbrain found
It is found posterior to the midbrain
134
What does the hindbrain join with?
It joins with the spinal cord
135
How many regions are there in the hindrain
3 major regions
136
What are the three regions of the hindbrain
- cerebellum
- pons
- medulla oblongata
137
Where is the cerebellum found
it is located right below the two cerebral hemispheres
138
What does the cerebellum do?
It controls limb movements, balance, and muscle tone.
Eg: simple actions of picking something up from the ground requires a large amount of signalling
Frontal lobe = starts the movement
Cerebellum = perfects the movement
139
What is the largest region in the hindbrain
the cerebellum
140
What role does the pons have?
- largely a relay station that passes information between the cerebrum, and the cerebellum.
- responsible for many basic functions needed for life
141
What is the role of the medulla oblongata
- It connects your brain to your spinal cord, and acts as a connection between the peripheral (PNS) and the central nervous system (CNS)
142
What else does the medulla oblongata do that is extremely important?
It controls involuntary muscle action (autonomic nervous system) which is extremely important for regulation of your cardiovascular and respiratory system.
143
What is true about the medulla oblongata?
Its the lowest part of the brain and lowest portion of the brainstem.
144
What does Autonomic Nervous System do
It works together with the endocrine system to adjust the body to changes in the external and internal environments
145
What is true about the correlation between autonomic nerves and motor nerves?
All autonomic nerves are motor nerves involved in regulation and involve many things that we can't control, like circulation, digestion, etc.
146
RECAP: what are the two opposing units of autonomic system
- Sympathetic nervous system
- Parasympathetic nervous system
147
Where do the nerves from the sympathetic nervous system come from?
They come from many vertebrae
148
What is the vagus nerve?
It is very important in the parasympathetic nervous system
149
From where do vagus nerves exit
These nerves exit directly from the brain or from the tailbone section of the spinal cord.
150
What are considered natural painkillers made in the brain?
Endorphins and enkephalins
151
How do endorphins and enkephalins work?
The greater amount of pain receptors attached to the injured organ, the greater perception of pain. These natural painkillers attach to special receptor sites in the spinal cord to block pain messages from going to the brain.
152
How do opiates work?
They work the same way as endorphins, however by taking them, the level of natural painkillers decrease.
153
What do depressants do?
Drugs that act as depressants enhance the action of inhibitory synapses by making (GABA) receptors stay open longer
- does this connect to opiates?
154
What is the role of the stimulus
It serves as a source of energy
Eg: taste receptors convert chemical energy into electrical energy— a nerve action potential
155
What are sensory receptors?
highly modified ends of sensory neurons.
156
What is done to allow stimulus threshold to be more easily reached?
Having different sensory receptors and connective tissues grouped within specialised organs like the eye or ear.
This is common
157
When does sensory adaptation occur?
They occur when sensory receptors become less sensitive when stimulated repeatedly
- means that condition isn't dangerous like your body usually doesn't feel the clothes your wearing all the time
158
What are the three layers in your eye
- sclera
- choroid layer
- retina
159
Sclera
Outermost layer of the eye that protects the eye's inner layers.
160
Why is sclera considered the white of the eye
It is the white part of the eye and the white fibrous sclera maintains the eye's shape
161
How do you identify the cornea
It is the clear front part of the sclera
162
How does the cornea gain its nutrients from? (or what is the role of the aqueous humour )
Its nutrients is supplied by aqueous humour
162
What is the role of cornea
this tissue bends light toward the pupil
163
What is the aqueous humor
It is the transparent fluid in a chemaber behind the cornea
164
What things are part of the sclera?
- cornea
- aqueous humour
- vitreous humour (technically not part of the outer layer though)
165
Choroid Layer
it is the middle layer (between the sclera and retina)
166
What is the role of choroid layer
it provides oxygen and nourishment to the outer later of the retina
167
Iris
the front of the choroid layer and its the coloured part of the eye
168
What is the role of the iris
it has muscles that control the size of the opening of the pupil, varying the amount of light coming into the eye.
169
Where is the lens found in the eye
It is immediately behind the iris
170
What is the role of the lens
It focuses the image onto the retina
171
What is the role of ciliary muscles
they alter the shape of the lens for focusing
172
Retina
innermost later
173
How many layers are there in the retina and what are they?
- light sensitive
- bipolar cells
- cells from the optic nerve
174
Light sensitive
positioned next to the choroid layer
175
What are the two types of light sensitive layers
- rods
- cones
176
What do rods do?
They respond to low-intensity light
177
What do cones do?
They require high-intensity light and identify colour
178
What do the bipolar cells do?
They relay messages from the rods and cones to the optic nerve
179
What do cells from the optic nerve do?
They carry these impulses from the optic nerve to the CNS
180
Fovea Centralis and its location is relation to the light sensitive layer
- small depression in the centre of the retina where your vision is the sharpest
- cones are packed close together, and where most of the light is sensed.
- Rods surround this fovea --> peripheral vision isn't in colour
181
Where is the blind spot in your eye
Where the optic nerve attaches to the retina and it has no rods or cones
182
How do the retina and brain collaborate
The retina receives images upside down and the brain turns then right side up
183
What are 6 examples of vision defects
- Glaucoma
- cataract
-astigmatism
- nearsightedness (myopia)
- farsightedness (hyperopia)
- presbyopia
184
Glaucoma
buildup of fluid in the eye. Blockage of drainage causes pressure that damages the retina
185
Cataract
lens/cornea becomes opaque blocking light
186
Astigmastism
lens or cornea abnormally shaped
187
Myopia (or nearsighedness)
can only see well close up
188
Hyperopia (farsightedness)
can't see well up close, only further away
189
Prebyopia
develops when we are in our mid-40s and we need reading glasses to see up close due to lens hardening
- THIS IS AGE RELATED
- WON'T1 BE ON TEST
190
What are the two main functions of the ear?
- hearing
- equilibrium
191
Where are sensory cells found in the ear
All sensory cells are in the inner ear
192
Why is it important that sensory cells have their tiny hairs
These tiny hairs respond to mechanical stimuli because movements of these hairs causes nerve cells to generate an impulse
193
How many sections is the ear divided in and what are these sections?
3 sections
- outer ear
- middle ear
- inner ear
194
What does the outer ear contain
- pinna
-audiotry canal
195
What does pinna do?
It is an external ear flap which collects sound
196
What does auditory canal do
It carriers sound to the ear drum
197
What does the middle ear contian
- tympanic membrane
- ossicles
- eustachian tube
198
What is another name for tympanic membrane
It is the eardrum
199
What are ossicles
3 small bones
200
Where does the eustachian tube trail from
It extends from the middle ear to the mouth and chambers of the nose, to equalise air pressure.
201
What does the inner ear contain
- semi-circular canals
- vestibule
- cochlea
202
What is the purpose of semi-circular canals
They are used for balance
203
Where are vestibules and what do they do?
They are found at the base of the canals which establishes head position
204
What does the cochlea do?
It is used for hearing
205
How does hearing happen?
Sound waves push against the ear drum, passed on to 3 tiny bones (ossicles) arranged in a lever system, which concentrates this tympanic motion onto the oval window
--> sends off motion of fluid in the cochlea
--> tiny hairs pick up the fluid's motion inside and it is interpreted as sound
206
Oval window
a small oval-shaped hole in the inner ear
207
How is pitch sensed?
The cochlea becomes progressively narrower as it coils, and only higher frequencies can stimulate this area
low pitch--> can make it all the way
high pitch --> doesn't make it all the way
208
2 Types of Equilibrium
- Static Equilibrium
- Dynamic Equilibrium
209
Static Equilibrium
Sacs in your head filled with gelatinous material contain calcium carbonate ""rocks" which move around and bend hairs --> sense horizontal and vertical movement (acceleration)
210
Dynamic Equilibrium
Three fluid-filled semi circular canals (different angles to each other) sense motion in all directions/ 3D (XYZ coordinates).
- Haris inside detect changes in motion of the fluid in each spatial plane.
Biology
flashcards
Decks in class (12)
# Cards
-
Chapter 2- Cellular Respiration92
-
Chapter 3- Photosynthesis88
-
Chapter 4- DNA53
-
Chapter 5- Protein149
-
Chapter 6- Biotechnology92
-
Chapter 7- Excretory System170
-
Chapter 8- Endocrine System170
-
Chapter 9- Nervous System211
-
Chapter 10- Immune System122
-
Chapter 14- Population Dynamics100
-
Chapter 1- Biochemistry207
-
Chapter 1530
