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HSC1007 A&P > Neurophysiology > Flashcards

Neurophysiology Flashcards

1
Q

What are the general functions of the nervous system?

A
  1. Sensory (internal - e.g. BP & external - e.g. ppl. touch you)
  2. Communicative (within body system)
  3. Integrative (integrates info - e.g. you see wild boar = inc HR)
  4. Motor (movement)
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2
Q

What does the central nervous system consist of?

A

Brain
Spinal cord

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3
Q

What does the peripheral nervous system consist of?

A

Nerve fibers (made of axons of neurons)

neurons = nerve cells

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4
Q

The nervous system is organised into:

A
  • Central Nervous System (CNS)
  • Peripheral Nervous System (PNS)
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5
Q

How many pairs of cranial nerves are there?

A

12 pairs !!

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6
Q

What are cranial nerves?

A

Nerves…
Can be a motor nerve or a sensory nerve OR both
Each nerve is responsible for a function (e.g. vagus nerve - main nerve for parasympathetic NS)

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7
Q

How many pairs of spinal nerves are there?

A

31 pairs !!

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8
Q

Where does the spinal cord end and what follows after?

A

Spinal cord ends around L1

After spinal cord ends, there is the Cauda equina (from L1 to Co)

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9
Q

Where does cervical nerve 8 lie?

A

Since there are only 7 cervical vertebrae, cervical nerve 8 lies BELOW C7

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10
Q

Where do the nerves lie before C7?

Where do the nerves lie after C7?

A

Before C7, the nerves lie BEFORE vertebrae

After C7, the nerves lie AFTER vertebrae

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11
Q

What is the PNS divided into?

A
  • Afferent division (“A” for advance)
  • Efferent division (“E” for exit)
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12
Q

What does the afferent division of the PNS do?

A
  • Carries info to CNS (“A” for advance = advance into CNS (enters)
  • Sensory & visceral (from internal organs) stimuli

Basically the input

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13
Q

What does the efferent division of the PNS do?

A

Transmit information from the CNS to effector organs (“E” for exit = exits CNS to go to organs)

Basically the output

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14
Q

What is the efferent nervous system divided into?

A
  • Somatic nervous system
  • Autonomic nervous system
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15
Q

What is the somatic nervous system?

A
  • Fibers of motor neurons that supply skeletal muscles
  • Subjected to VOLUNTARY control
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16
Q

What is the autonomic nervous system (ANS)?

A
  • Fibers that innervate smooth muscle, cardiac muscle, & glands
  • INVOLUNTARY
  • Sympathetic & parasympathetic
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17
Q

What does an autonomic nerve pathway consist of?

A

two-neuron chain (in general!)

  • Preganglionic neuron
  • Postganglionic neuron
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18
Q

What does the preganglionic neuron do?

A

It synapses with the cell body of the postganglionic fiber in a ganglion outside the CNS

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19
Q

What is a synapse?

A

Connection b/w two neurons

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20
Q

What does the postganglionic neuron do?

A

Sends axons that end on the effector organ

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21
Q

What is a ganglion?

A

Cluster of neuronal cell body

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22
Q

What is dual innervation?

A

Innervation of a single organ by both branches of the autonomic nervous system

Sympathetic & parasympathetic dually innervate most visceral organs

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23
Q

Sympathetic

Parasympathetic

A

Sympathetic: “fight-or-flight”

Parasympathetic: “rest-and-digest”

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24
Q

Where are preganglionic neurons located in the sympathetic NS?

A

Located between segments T1 and L2 of the spinal cord

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25
Q

Where are the ganglion located in the sympathetic NS?

A

Closer to the spinal cord = can trigger action potential to a lot of neurons that lead to many different effectors

Small signal send down 1 path can trigger many effectors at once (bc one ganglion = many postganglionic fibers)

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26
Q

Why are post ganglionic fibers longer in the sympathetic NS?

A

Post ganglionic fibers are longer to ensure rapid & widespread responses

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27
Q

Which are longer:
- Preganglionic fibers
- Post ganglionic fibers

A

Post ganglionic fibers are longer

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28
Q

Where do the sympathetic fibers originate from?

A

Thoracolumbar region = T1 to L2

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29
Q

Where do parasympathetic fibers originate from?

A

Craniosacral division = cranial, trunk, pelvic (above & below where the sympathetic fibers originate)

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30
Q

Parasympathetic innervation distribution

A

Long preganglionic & short postganglionic (more specific signals)

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31
Q

Effects of sympathetic stimulation on organs

A

Just read through –> can think of it on the spot (slide 16 of neuro1)

Sympathetic –> physical, stressful

  • Heart: Inc HR & inc force of contraction of heart
  • Most innervated blood vessels: constricts
  • Lungs: dilates bronchioles, inhibits mucus secretion
  • Digestive tract: dec motility, inhibits digestive secretions, contracts sphincters (prevent forward movement of food)
  • Urinary bladder: relaxes
  • Eye: dilates pupil, adjusts eye for far vision
  • Liver: glycogenolysis (glucose released)
  • Adipose cells: lipolysis (fatty acids released)
  • Exocrine glands: inhibits pancreatic exocrine secretion, stim secretion of sweat glands, stim small vol. of thick saliva rich in mucus
  • Endocrine glands: stim epinephrine & norepinephrine secretion, inhibit insulin secretion, stim glucagon secretion,
  • Genitals: controls ejaculation & orgasmic contractions
  • Brain activity: inc. alertness
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32
Q

Sympathetic NS vs Parasympathetic NS

A

Origin of preganglionic fibe:
- Sym: thoracic & lumbar region of spinal cord
- Para: brain & sacral region of spinal cord

Origin of postganglionic fiber:
- Sym: ganglion chain (near spinal cord) OR collateral ganglia (in b/w spinal cord & effector organs)
- Para: terminal ganglia (in/near effector organs

Fiber length:
- Symp: Short preganglionic fibers, long postganglionic fibers
- Para: Long preganglionic fibers, short postganglionic fibers

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33
Q

What is grey mattetr?

A

Generic term for collection of cell bodies (soma) in CNS

(DIFFERENT from ganglion = collection of cell bodies OUTSIDE CNS)

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34
Q

What is white matter?

A

Generic term for collection of CNS axons

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35
Q

How is the CNS protected from injury?

A
  1. Cranium & vertebral column
  2. Meninges (covers brain & spinal cord)
  3. Cerebrospinal fluid
  4. Blood-brain barrier
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36
Q

What is meninges?

A
  • Three meningeal mbns
  • Wrap, protect & nourish CNS
  • Continuous with spinal meninges
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37
Q

What are the three meningeal membranes?

A
  1. Dura mater (most superficial; tough & inelastic )
  2. Arachnoid matar
  3. Pia mater (most inside - closely adhered to brain surface
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38
Q

What is located between the Arachnoid matar and the Pia matar?

A

Subarachnoid space
- Spiderweb-like structure
- Spaces b/w the spiderweb-like structure (lines) = Cerebrospinal fluid

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39
Q

How does the cerebrospinal fluid (CSF) protect the CNS?

A
  • Shock absorbing fluid
  • Brain floats in CSF, so surrounded by CSF and it cushions brain & spinal cord
  • Cushions delicate neural structures
  • Supports brain
  • Transports nutrients, chemical messengers, wastes products
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40
Q

Where is cerebrospinal fluid formed?

A

Produced by ependymal cells of the choroid plexuses in ventricles (fluid-filled cavities) in brain

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41
Q

What are the ventricles of the brain?

A

Fluid filled cavities (filled with CSF)
Connected to e/o so CSF can flow from 1 ventricle to another

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42
Q

Production of CSF

A
  1. Produced by ependymal cells of choroid plexuses (in one of the ventricles)
  2. Circulates throughout the ventricles
  3. Exits 4th ventricle
  4. Flow into subarachnoid space
  5. Reabsorb into venous blood
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43
Q

How does the blood-brain barrier protect the CNS?

A
  • Isolates CNS neural tissue from general circulation
  • Highly selective BBB regulates Xchanges b/w blood & brain
  • Allows chemical composition of bld. & CSF to differ
  • Selectively isolates brain from chemicals in blood that might disrupt neural function
  • Limits use of drugs for treatment of CNS
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44
Q

What is the BBB formed by?

A

Formed by network of tight junctions (formed by capillaries)

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45
Q

How is the CNS nourished?

A

Brain depends on constant delivery of oxygen & glucose by blood

bc. brain only utilizes glucose but X store it & X produce ATP w/o O2

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46
Q

What happens if brain is deprived of O2?

A

brain damage
- bc X anaerobic respiration

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47
Q

What % of body weight is the brain?

A

About 2% of body weight
BUT requires 13-15% of cardiac output

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48
Q

General functions of the central nervous system (CNS)?

A
  1. Subconsciously regulate homeostatic responses
  2. Experience emotions
  3. Voluntary control movements
  4. Perception of body & surroundings (inc. proprioception)
  5. Engage in other higher cognitive processes
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49
Q

What are the components of the brain?

A
  1. Brain stem
  2. Cerebellum
  3. Forebrain
    - Diencephalon: Hypothalamus & Thalamus
    - Cerebrum: Basal nuclei (basal ganglia)
    - Cerebral cortext
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50
Q

Which 3 structures in the brain ensure proper control of movement?

A
  1. Cerebral cortex
  2. Basal nuclei
  3. Cerebellum
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51
Q

What are the functions of the cerebral cortex?

A
  • Sensory perception
  • Voluntary control of movement
  • Language
  • Personality traits
  • Cognitive processes = thinking, memory, decision making, self-consciousness, creativity
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52
Q

What are the functions of the basal nuclei?

A
  • Inhibition of muscle tone
  • Coordination of slow, sustained movements
  • Suppression of useless patterns of movement
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53
Q

What are the functions of the thalamus?

A
  • Relay station for all synaptic input EXCEPT olfactory input
  • Crude awareness of sensation
  • Some degree of consciousness
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54
Q

What are the functions of the Hypothalamus?

A
  • Regulation of many homeostatic functions
  • Important link b/w nervous & endocrine systems
  • Extensive involvement with emotion & basic behavioural patterns
  • Role in sleep-wake cycle
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55
Q

What are the functions of the cerebellum?

A
  • Maintenance of balance
  • Enhancement of muscle tone
  • Coordination & planning of skilled voluntary muscle activity
56
Q

What are the functions of the brainstem?

A
  • Origin of majority of peripheral cranial nerves
  • Cardiovascular, respiratory & digestive control centers
  • Regulation of muscle reflexes involved with equilibrium & posture
  • Reception & integration of all synaptic input from spinal cord; arousal & activation of cerebral cortex
  • Role in sleep-wake cycle
57
Q

What are the four lobes of the cerebral cortex?

A
  1. Frontal lobe
  2. Parietal lobe
  3. Occipital lobe
  4. Temporal lobe
58
Q

What is the main function of temporal lobe?

A

Memory formation

59
Q

What is the main function of the frontal lobe?

A

Prefrontal - complex cognitive, decision making, personality, social behaviour

60
Q

What is the main function of the parietal lobe?

A

Somatosensory processing

61
Q

What is the main function of the occipital lobe?

A

Visual

62
Q

What is the sensory & motor homunculus?

A

Somatotopic map
- Proportion of somatosensory cortex devoted to reception of sensory input from each area
- Dist. of motor output from primary motor cortex to diff parts of the body
- Precise dist. is unique for each individual

  • Use-dependent modification (can change with activity –> plasticity)
63
Q

What is the spinal cord?

A

Long, slender cylinder of nerve tissue that extends from brain stem through vertebral canal & is connected to spinal nerves
- enclosed by protective vertebral column

64
Q

What resides in the dorsal root ganglion?

A

Cell bodies of sensory afferent system

65
Q

What are dermatomes?

A

Area of skin is supplied by a single spinal cord level (or a single spinal nerve on one side)
- Localise lesions to a specific spinal nerve/spinal level

66
Q

What are myotomes?

A

Portion of skeletal muscle innervated by a single spinal cord level, (or a single spinal nerve on one side)

  • Each skeletal muscle usually innervated by nerves from MORE THAN ONE spinal cord level
67
Q

What information does the posterior root carry?

A

Posterior/dorsal root

Carries sensory information

68
Q

What information does the ventral root carry?

A

Carries motor information

69
Q

What does the ramus carry?

A

Sensory & motor information

Anterior ramus - go to the anterior side (skin & muscle on anterior side of trunk)
Posterior ramus - go to posterior side (skin & skeletal muscles of the back)

70
Q

Dorsal & Ventral horn

A

Dorsal horn –> sensory information

Ventral horn –> motor information

The grey matter split in half

71
Q

What are nerve plexuses?

A

Network of nerves that come together & then redistribute themselves out with a different distribution of nerves into the limbs

Either somatic or visceral

72
Q

What happens in nerve plexuses?

A
  • Fibers combine from different sources/level –> form new nerves with specific targets/destinations
  • Each nerve exiting the plexus may contain fibers from diff spinal nerves
73
Q

Advantage of nerve plexuses

A

When a muscle is innervated by nerves from a nerve plexus, damage to a single spinal nerve is less likely to result in total paralysis of that muscle

74
Q

Do plexuses affect dermatome?

A

No!! Even with nerve plexuses, you can still have dermatome –> does not affect outcome)

Note: Dermatomes can overlap!

75
Q

What are neurons?

A
  • Basic functional units of the nervous system
  • Conducting cells of the nervous system –> processes & transmit info (electrical & chemical)
76
Q

Structure of neurons

A
  1. Cell body (aka soma) –> contains organelles essential for survival (nucleus, mitochondria, etc)
  2. Short, branched dendrites –> highly branched, receives info from other neurons
  3. Long, single axon –> carries electrical signal (action potential) to target
77
Q

What kinds of neurons are there?

A
  1. Bipolar neuron
  2. Unipolar neuron
  3. Multipolar neuron
78
Q

Bipolar neuron

A

Rare –> found in organs for sight/sound/smell

Has two processes separated by the cell body

Basically: dendrite –> cell body –> axon
(cell body sandwiched b/w dendrite & axon)

79
Q

Unipolar neuron

A

Common for sensory afferents

Has a single elongated process, with cell body located off to the side

Basically: axon & dendrite are continuous

80
Q

Multipolar neuron

A

Common in CNS

Have more than two processes –> single axon & multiple dendrites

81
Q

What are neuroglia?

A

Non-conducting cells –> support neuronal function
~50% of total cell population in nervous system

82
Q

Types of neuroglia

A
  1. Astrocytes
  2. Myelinating glia
  3. Microglia
  4. Ependymal cells
83
Q

What do astrocytes do?

A

Regulate chemical content of the extracellular space

84
Q

What are some myelinating glia?

A

Oligodendrocytes (CNS) & Schwann cells (PNS)

85
Q

What do microglia do?

A

Phagocytic role –> engulf cells, remove cell debris/wastes
Immunity

86
Q

What do ependymal cells do?

A

Produce CSF

Located in choroid plexuses in ventricles

87
Q

Definitions of membrane potentials (?)

  1. Polarization
  2. Depolarization
  3. Repolarization
  4. Hyperpolarization
A
  1. Polarization: mbn potential is not 0 mv
  2. Depolarization: potential becomes less polarized than resting potential (moves towards 0)
  3. Repolarization: potential returns to resting potential after being depolarized (moving back towards -70mv)
  4. Hyperpolarization: potential becomes more polarized than resting potential (moves past -70mv)
88
Q

What do nerves use to communicate?

A

Neurons use electrical signals to receive, process, initiate, transmit messages –> sends to muscle cells

Electrical signals initiate contraction in muscle cells

89
Q

Why is the resting membrane potential -70 mv?

A

Equilibrium potential of K+ is -90mv
Equilibrium potential of Na+ is +60mv

K+ exerts the dominant effect on resting mbn potential bc mbn is more permeable to K+
(small net diffusion of Na+ neutralizes some of the potential created by K+)

So, resting potential closer to equilibrium of K+ instead of Na+

90
Q

What does the Na+-K+ pump do?

A

Actively transports Na+ out of the cell & K+ into the cell

–> keeps conc of Na+ high in ECF & keeps conc of K+ high in ICF

91
Q

How are electrical signals produced?

A

Produced by changes in ion movement across the plasma mbn
- event triggers a change in mbn potential
- alters mbn permeability –> alters ion flow across mbn

92
Q

What kind of gated channels are there?

A
  1. Voltage gated (changes in mbn potential)
  2. Chemically gated (e.g. neurotransmitters: acetylcholine –> open/close in response)
  3. Mechanically gated (e.g. can be pulled open)
  4. Thermally gated (in response to temp)
93
Q

How do voltage gated channels work?

A

When there is a voltage threshold –> there is a voltage gated channel (detect changes in mbn potential/threshold values)

When certain voltage (threshold voltage) is reached (e.g. depolarizing event) –> gate opens

94
Q

What are graded potentials?

A
  • Local changes in mbn potential
  • Occurs in varying grades/degrees of magnitude/strength
    (stronger triggering event = larger resultant graded potential)
95
Q

Action potential vs graded potential

A

Action potential:
- No size –> either HAVE or DON’T HAVE
- Can travel across axon

Graded potential:
- Can be varying degrees of magnitude/strength
- Cannot travel over axon, spread locally only

96
Q

How are graded potentials spread?

A

Spread by passive current flow
- Current: any flow of electrical charges
- Resistance: hindrance to electrical charge movement

Locallly!!
DIE OUT over short distances

97
Q

What are action potentials?

A

Brief, rapid, large changes in mbn potential

  • Inside of excitable cell transiently becomes more +ve than the outside
98
Q

What leads to action potentials?

A

Marked changes in mbn permeability & ion movement lead to an action potential

99
Q

What are the ion channels involved in the generation of action potentials?

A

Voltage-gated sodium channel
Voltage-gated potassium channel

100
Q

Which voltage-gated ion channel opens first?

A

Na+ opens first because rapid compared to K+

K+ is delayed in opening

BUT both are triggered at threshold

101
Q

What are the three states of the voltage-gated sodium channel?

A
  1. Closed but capable of opening (inactivation gate is open)
  2. Open (activated)
  3. Closed & not capable of opening (inactivated)
102
Q

Steps in generation of action potentials (8 steps)

A
  1. Resting potential: all voltage-gated channels closed
  2. At threshold, Na+ channel opens (activated) & permeability of Na+ inc.
  3. Na+ rush in –> causes explosive depolarization to +30 mv –> generates rising action potential
  4. At peak of AP, Na+ channel inactivated, permeability of Na+ dec. (net movement of Na+ ends), K+ channel opens & permeability of K+ inc.
  5. K+ leaves cell –> repolarization to resting potential –> generates falling phase of AP
  6. Return to resting potential –> Na+ channel resets to “closed but capable of opening” state –> ready to respond to another depolarising triggering event
  7. Further outward movement of K+ through still-open K+ briefly hyperpolarizes mbn –> generates after hyperpolarization
  8. K+ channel closes & mbn returns to resting potential
103
Q

What happens when membrane potential has been restored to resting (at the completion of an action potential)?

A

Ion distribution has been altered slightly (only small amounts of Na+ rush in & K+ rush out)

104
Q

Where are action potentials propagated from?

A

From the axon hillock to the axon terminals

105
Q

Na+-K+ pumps

A
  1. Pump has:
    - 3 high-affinity sites for Na+
    - 2 low-affinity for K+
    when exposed to ICF
  2. When Na+ from ICF (conc. low) binds to pump –> splits ATP into ADP + phosphate group binds to pump
  3. Phosphorylation causes pump to change conformation = Na+ binding sites are exposed to opposite side of mbn & 3 Na+ are released ECF –> affinity of Na+ binding sites greatly dec.
  4. Change in shape also exposes pump’s binding sites for K+ to ECF & greatly inc. affinity of K+ sites
  5. When 2 K+ from ECF (conc low) bind to pump –> release phosphate group. Dephosphorylation causes pump to revert to its original conformation
  6. Two K+ are released to ICF (K+ conc. high) as affinity of K+ binding sites dec. during change in shape
    At same time: affinity of Na+ binding sites inc.
106
Q

How does action potential propagate along an axon?

A
  1. Input zone (dendrites) –> receives incoming signals from other neurons
  2. Trigger zone (axon hillock) –> initiates action potentials
  3. Conducting zone (axon) –> conducts action potentials in undiminishing fashion, often over long distances
  4. Output zone (axon terminals) –> releases NT that influences other cells
107
Q

What does refractory period do?

A
  • Ensures one-way propagation of AP & limits their frequency
  • Prevents tetanic contraction
  • Cannot be initiated in a region that has just undergone an AP (for a while)

BASICALLY,
during repolarization, cannot have another AP

108
Q

What do the “backward” current and “forward” current do?

A

“Backward” current flow = X reexcite previously active area bc area is in refractory period

“Forward” current flow = excites new inactive area

109
Q

What is absolute refractory period?

A

Membrane CANNOT respond to further stimulation
IMPOSSIBLE to send more AP

Inactivation of Na+ channels & activation of K+ channels to start repolarization

110
Q

What is relative refractory period?

A

Membrane CAN respond only to a LARGER-than-normal stimulus

Time lag in closing all K+ channels leading to temporary hyperpolarization

Basically, Relative refractory period happens after absolute refractory period

111
Q

Can weak stimuli initiate AP?

A

NO
Does not initiate AP bc it doesn’t cross threshold
AP allows discrimination of stimuli –> all or NONE

112
Q

How does the strength of stimulus affect AP?

A

The stronger the stimulus, the higher the frequency of AP

Magnitude of each AP is the SAME but frequency can CHANGE

113
Q

What increases the speed of conduction of action potentials?

A

Myelination

Myelin + fiber diameter = inc. speed of conduction

114
Q

What influences the velocity of action potential propagation?

A

Fiber diameter

115
Q

What is myelination?

A

Myelin = thick layer of lipids
Acts as insulation to “electrical transmission” along the axon

116
Q

Advantages of saltatory conduction

A
  1. Faster bc have myelin
  2. Can keep the strength of the AP
117
Q

What happens in saltatory conduction?

A
  1. Action potentials occurs at the 1st node
  2. Na+ flows into the axon through Na+ channels
  3. Local current flow depolarises adjacent node
  4. Second node reaches threshold & AP occurs
  5. Na+ gate opens & Na+ rushes in
  6. At the same time (as 5), outward flow of K+ restores 1st node to resting potential

so AP jumps from node to node

118
Q

What is a synapse?

A

Junction b/w neurons

119
Q

What are electrical synapses?

A

Neurons connected directly by gap junctions

120
Q

What are chemical synapses?

A

Chemical messenger transmits information one way across a space separating two neurons

Most synapses in human NS are chemical synapses

121
Q

Anatomy of chemical synapse

A

Presynaptic terminal - from the axon

Postsynaptic dendrite - receives

Synaptic cleft - space b/w the presynaptic terminal & postsynaptic dendrite

122
Q

Steps in the synaptic transmission

A
  1. Depolarization:
    Presynaptic terminal is depolarized –> AP travels down & reaches axon terminal (results in step 2)
  2. Influx of calcium:
    Opening of voltage-gated Ca2+ which results in influx of Ca2+
  3. Docking:
    Ca2+ signals synaptic vesicles (contains neurotransmitters) to docking protein
  4. Release of Neurotransmitter:
    Once the synaptic vesicles dock, neurotransmitters are released into synaptic cleft
  5. Binding of neurotransmitter to receptor:
    On postsynaptic terminal
    The binding of neurotransmitters to receptor usually results in that ion channel opening
123
Q

What happens to the neurotransmitter after synaptic transmission?

A

Must be broken down/removed from the synapse
If it remains there, it will constantly activate post synaptic neuron

124
Q

How many inputs can a neuron receive?

A

MULTIPLE inputs from MANY presynaptic axons

125
Q

What are receptor channels?

A

Combined receptor & channel units
Present in postsynaptic neuron

126
Q

Types of synapses

A
  • Excitatory synapses
  • Inhibitory synapses
127
Q

What are excitatory synapses?

A

Generation of excitatory post-synaptic potential

Brings resting mbn potential closer to the threshold

127
Q

What are inhibitory synapses?

A

Generation of inhibitory post-synaptic potential

Brings resting mbn potential away from threshold

127
Q

How do drugs & diseases affect synaptic transmission?

A
  • Can modify synaptic transmission
  • Agonise/Antagonize the receptors
  • Influence NS function by altering synaptic mechanisms (most affect neurotransmitter receptors by e.g. blocking/enhancing action/activating)
127
Q

How are neurons linked?

A

Convergence
Divergence

128
Q

Convergence pathway of neurons

A

Neuron may have many other neurons synapsing on it –> lots of signals converge

basically, one cell influenced by many others

129
Q

Divergence pathway of neurons

A

Branching axon terminals so a single cell synapses & influences other cells –> signal diverted

basically, one cell influences many others

130
Q

Functions of acetylcholine

A

PNS: Neuromuscular junctions, parasympathetic nerves

Usually generates excitatory post-synaptic potential

131
Q

Function of dopamine

A

Involved in many pathways in CNS (such as muscle movement & reward pathway)

132
Q

Function of glutamate

A

Primary excitatory neurotransmitter in CNS (excitatory post-synaptic potential)

133
Q

Function of Gamma-aminobutyric acid (GABA)

A

Primary inhibitory neurotransmitter in CNS (inhibitory post-synaptic potential)

134
Q

Effect of parasympathetic stimulation on organs

A

Just read through –> can think of it on the spot (slide 16 of neuro1)

Parasympathetic –> relax, chill, quiet

  • Heart: Dec HR & dec force of contraction of atria
  • Most innervated blood vessels: dilates vessels supplying to genitals
  • Lungs: constricts bronchioles, stim mucus secretion
  • Digestive tract: inc motility, stim. digestive secretions, relaxes sphincters (prevent forward movement of food)
  • Urinary bladder: conttracts
  • Eye: constricts pupil, adjusts eye for near vision
  • Liver: none
  • Adipose cells: none
  • Exocrine glands: stim pancreatic exocrine secretion, stim large vol of watery saliva rich in enzymes
  • Endocrine glands: stim insulin & glucagon secretion
  • Genitals: controls erection
  • Brain activity: none

HSC1007 A&P (8 decks)

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