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Mammalian physiology > Nervous system - Lectures 8-9 (ANS) > Flashcards

Nervous system - Lectures 8-9 (ANS) Flashcards

1
Q

Effector organs of somatic motor system (1) vs autonomic nervous system (4)?
- how many effector neurons per system ish
- voluntary or involuntary

A
  • somatic –> skeletal muscles! –> 1 neuron –> voluntary
  • autonomic –> smooth muscle, cardiac muscle, exocrine/endocrine glands, adipose tissue –> 2 neurons –> MOSTLY involuntary –> can be voluntary with traning (ie peeing, pooping, meditation)
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2
Q

sympathetic = _____ or ______
parasympathetic = ______ and ______

A
  • SNS: fight or flight
  • PNS: rest and digest
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3
Q
  • Autonomic reflexes work with (2) systems to maintain ___________
  • control center of autonomic reflexes –> 3
  • what does autonomic reflexes do? (2)
A
  • work with endocrine and behavioral system to maintain homeostasis
  • hypothalamus + brain stem (pons, medulla) + spinal reflex (doesn’t need integration in brain)
  • receives (?) sensory info from somatosensory and visceral receptors + motor output leads to autonomic, endocrine and behavioral responses
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4
Q
  • behavioral responses may be integrated in _____ _______ into _______ behaviors and to control ___________
  • sensory info that are integrated in ______ and ______ system, create ________ that influence autonomic output
A
  • brain centers into motivated behaviours to control movement
  • integrated in cortex and limbic system, create emotions
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5
Q

autonomic center has control over 2 major organs
- what does each of these organs control? 5 each

A

HYPOTHALAMUS:
- temp control
- water balance
- eating behavior
- sleep
- sex drive
BRAIN STEM:
- urinary bladder control
- blood pressure control
- respiratory system + secondary respiratory system
- heart beat
- swallowing/digesting

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6
Q

most internal organs are under __________ control –> one branch is excitatory, the other branch is inhibitory
- 2 exceptions
- what determined response in target tissue?

A
  • antagonistic
  • sweat glands (epithelial cells) and smooth muscles in most blood vessels/arteries –> ONLY sympathetic innervation + tonic control
  • neurotransmitter receptor!
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7
Q

what is dual innervation?
- what is tone?

A

DUAL INNERVATION:
- target organ can get input from both sympathetic and parasympathetic –> technically both systems have opposite functions (ie accelerate or brake)
TONE:
- both function at same time but 1 is dominant (ie heart beat: sympathetic dominant when you run vs when you sleep, parasymp. is dominant –> shows tonic control (?))

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8
Q

preganglionic vs postganglionic neuron
- combientième neuron in chain + cell body located where?
- projects from where to where?
- synapses to what?

A

PREGANGLIONIC:
- first neuron in chain with cell body located in CNS
- projects from CNS to an autonomic ganglion outside CNS
- synapses with postganglionic neuron
POSTGANGLIONIC:
- 2nd neuron in chain with cell body located in autonomic ganglion
- projects from autonomic ganglion to target tissue
- synapses with target cell

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9
Q

ganglion = what?
- also contain what?
- act as what?

A
  • ganglion = cluster of neuronal cell bodies outside CNS
  • also contain neurons completely within
  • act as mini integration centers
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10
Q

autonomic pathways consists of # neurons that synapse where?

A

2 neurons that synapses in an autonomic ganglion

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11
Q

synapse vs neural effector junction vs neural muscular junction

A
  • synapse: connection between 2 neurons
  • neural effector junction: between 1 neuron and effector cell that is not skeletal muscle
  • neural muscular junction: btw 1 somatic motor neuron and 1 skeletal muscle fiber
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12
Q

sympathetic pathway:
- branches out from which regions of spinal cord?
- sympathetic ganglia in 2 ganglion chains along either side of what?

A
  • thoracic and lumbar regions of spinal cord –> T1 to T12 + L1-L2
  • either side of vertebral column
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13
Q

3 scenarios for sympathetic post-ganglionic neurons?

A
  1. axon synapses with postganglionic neurons in first ganglion it reaches (short first neuron + long 2nd neuron)
  2. axon may continue, without synapsing, through sympathetic trunk ganglion to end at a prevertebral/collateral ganglion (halfway btw spinal cord and effector organ) and synapse with postganglionic neurons there
  3. axon may passe through sympathetic trunk ganglion and collateral ganglion and then to the adrenal medulla (no synpases –> adrenal medulla can produce hormones (endocrine system)
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14
Q

what is the most dominant pathway for SNS?

A

chain ganglions! short first neuron –> synapse in sympathetic ganglion chain –> long postganglionic neuron

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15
Q

parasympathic system:
- branches out from where
- which nerve accounts for 75% of PSNS?
- parasympathetic ganglia located on or near what?

A
  • brain stem + leave brain in cranial nerves (4 craniosacral nerves) + 3 sacrospinal nerves (S2, S3, S4)
  • vagus nerve!
  • near target organs
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16
Q

most dominant pathway for parasympathetic system?

A
  • quite long 1st neuron –> gets really close or into organ before interacting with terminal ganglion –> synpases with short postganglionic neuron
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17
Q

vagus nerve:
- contains about ___% of all para or sympathetic fibers?
- sensory info from what to what + output from what to what?

A
  • 75% of parasympathetic fibers
  • internal organs to brain + output form brain to organs
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18
Q

what are the 2 exceptions where parasympathetic and sympathetic don’t work oppositely?

A

SALIVA:
- watery saliva = increased by PSNS
- mucusy salive (more dry) = increase by SNS)
BLOOD VESSELS:
- SNS induces ejaculation + PSNS induces erection
- SNS stimulates uterus contraction + PSNS regulates engorgement and secretions

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19
Q

SNS or PSNS:
- relaxes airways
- constricts airways
- inhibits digestion
- slows heart rate
- increases bile secretion
- relaxes bladder
- release of urine
- increases motility and secretion in intestines
- pupil dilates
- increases renin secretion
- releases enzymes and insulin from pancreas

A
  • relaxes airways SNS
  • constricts airways PSNS
  • inhibits digestion SNS
  • slows heart rate PSNS
  • increases bile secretion PSNS
  • relaxes bladder SNS
  • release of urine PSNS
  • increases motility and secretion in intestines PSNS
  • pupil dilates SNS
  • increases renin secretion SNS
  • releases enzymes and insulin from pancreas PSNS
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20
Q

what neurotransmitter do sympathetic and parasympathetic PREganglionic neurons release?
- onto what receptor? 2 types

A
  • both release acetylcholine!
  • nicotinic cholinergie receptors (nAChR) on the postganglionic cells –> Nn (on neuron) or Nm (on muscle)
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21
Q

what neurotransmitter do sympathetic and parasympathetic POSTganglionic neurons release?
- onto what receptor?

A

SYMPATHETIC:
- norepinephrine –> adrenergic receptors on target cells (alpha (1 or 2) or beta (1, 2 or 3))
PARASYMPATHETIC:
- secrete acetylcholine onto muscarinic cholinergic receptors (mAChR) –> M1 to M5 (we focus on M2 and M3)

22
Q

exceptions!
- sympathetic cholinergic neurons (postganglionic) on sweat glands secrete what neurotransmitter? (instead of what normally?)
- which neurons use other types of neurotransmitters?

A
  • acetylcholine! instead of norepinephrine
  • nonadrenergic and noncholinergic neurons
23
Q

which nervous system:
- nicotinic cholinergic receptors
- muscarinic cholinergic receptors
- a adrenergic receptor
- b adrenergic receptor

A
  • Nn or Nm –> both SNS and PSNS
  • M1 to M5 –> PSNS
  • a1, a2, b1, b2, b3 –> SNS
24
Q

autonomic pathways control ______ and _____ muscle and _______
- what at the end of the postganglionic neuron can release autonomic neurotransmitters over surface of target cells? –> goal?

A
  • smooth and cardiac muscle and glands
  • varicosities! goal = increase effect of neurotransmitters
25
Q

____ node controls heartbeat
- mostly 2 receptors –> which one are controlled by which neurotransmitter from which autonomic division? –> result in heart rate

A

SA node
- increase b1 –> NE from SNS –> increase heartrate (contraction)
- decrease M2 –> Ach from PSNS –> decrease heart rate

26
Q

bronchial smooth muscle:
- which 2 receptors-neurotransmitter pair induces relaxation vs contraction?
VS smooth muscle blood vessel:
- which receptor is increased?

A
  • decrease b2 –> NE from SNS –> relaxation for running
  • increase M3 –> Ach from PSNS –> contraction (less air gets in/out)
  • smooth muscle: increase alpha (SNS) to increase blood pressure
27
Q
  • nicotinic receptors exist on all ________ _______
  • muscarinic receptors exist on all _________ _____ ________
  • which (3) actions ish are integrated at the spinal cord level?
  • vs centers for cardiovascular, respiratory and digestive activities are located in the ________
A
  • autonomic ganglia
  • effector cell membranes
  • urination, defecation, erection
  • medulla
28
Q

roles + mostly found where?:
- a1: contraction of (2)
- a2: (5)

A

a1: contraction of vascular and genitourinary smooth muscle
- mostly found in smooth muscle for blood vessels + most sympathetic target tissues
a2:
- contraction of vascular smooth muscle
- decreased insulin secretion
- decreased cAMP
- aggregation of platelets
- pre-synaptic inhibition of NE
- found in gastrointestinal tract and pancreas

29
Q

roles + found in?
- b1: effects on ?
- b2: relaxes (4) + stimulates (2) in liver
- b3: ?

A

b1: positive inotropic and chronotopic effects on heart –> increase heart contraction
- found in heart muscle, kidney
b2:
- relaxes vascular, bronchial, gastrointestinal and genitourinary smooth muscle
- stimulaes glyconeolysis and gluconeogenesis in liver
- found in certain blood vessels and smooth muscle of some organs + bronchile!
b3: lipolysis in adipose tissue
- found in adipose tissue

30
Q

what medication will block which receptors to decrease high blood pressure?

A
  • beta block!
  • block b receptors –> effect from SNS will decrease = more PSNS –> decrease heart rate
31
Q

REVIEW OF SYNAPSES:
- 2 things can happen when neurotransmitters bind to receptors?
- first thing –> 3 different molecules –> 2 different results
- 2nd thing –> what happens?

A
  1. can open channels!
    - Na+ OR Ca2+ channels –> get into cells = depolarization = graded potential –> Excitatory post synaptic potentials (EPSP) –> needs to go through summation to get AP
    - Cl- channels –> get into cells = hyperpolarization –> IPSP
  2. can bind to G protein coupled receptors –> induce 2° messengers –> enzyme changes –> may or may not induce AP
32
Q

GPCR, ion channels or both?
- alpha and beta adrenergic receptors
- nicotinic and muscarinic receptors

A
  • a and b –> GPCR
  • N and M –> GPCR and some ion channels –> can change membrane potential
33
Q

3 components of the neuromuscular junction?

A
  1. axon terminal
  2. synaptic cleft
  3. motor end-plate
34
Q

what is EPP? how is it induced? (4)

A
  • end-plate potential!
  • Nm receptors on motor end-plate open sodium channels –> changes membrane potential –> induces EPP –> always big enough to reach threshold = AP!
35
Q

Action potential arrives at varicosity –> (+4 steps)
- how to “remove” neurotransmitter? (3)

A
  1. AP at varicosity
  2. depolarization opens voltage gated Ca2+ channels
  3. Ca2+ entry triggers exocytosis of synaptic vesicles –> release NE
  4. NE binds to adrenergic receptor on target
  5. receptor activation ceases when NE diffuses away from synape
  6. NE can be taken back into synaptic vesicles for re-release
  7. NE is metablized by monoamine oxidase (MAO) which breaks down NE
36
Q

reacts more to NE or E? or both?
- alpha receptors
- b1
- b2
- b3

A
  • alpha receptors: strongly to NE (and weakly to E)
  • b1 (heart): equally to NE and E
  • b2 (bronchile): more sensitive to E than NE
  • b3: more sensitive to NE than E
37
Q

neurotransmitters in SYMPATHETIC VS PARASYMPATHETIC
- synthesized from?
- inactivation enzyme?
- varicosity membrane transporters for? (when reuptaken into presynaptic neuron?

A

SYMPATHETIC:
- NE synthesized from tyrosine
- monoamine oxidase (MAO) in mitochondria of varicosity
- NE
PARASYMPATHETIC:
- Ach synthesized from acetyl-CoA + choline
- Acetylcholinesterase (AChE) in synaptic cleft
- choline (only choline is left after AChE activity)

38
Q

effects of a1, a2, b1, b2 and b3 on second messengers?

A

a1 –> increases IP3 and intracellular Ca2+ + increases PKC
a2 –> decreases cAMP
b1, b2 and b3 –> increases cAMP

39
Q

where are each cholinergic receptors found in? + effect on second messenger?

A

Nn:
- postganglionic autonomic neurons
- opens non specific monovalent cation channels
Nm:
- skeletal muscle
- opens non specific monovalent cation channels
M1, M2, M3, M4 and M5: nervous system and parasympathetic target tissues
M1, M3 and M5 –> increases IP3 and intracellular Ca2+ + increases PKC (induces bronchile contraction)
VS M2 and M4 –> decreases cAMP, opens K+ channels (more hyperpolarization –> decrease heart contraction)

40
Q

why is smoking a cardiac risk factor? (2)

A
  1. blood vessels are primarily influenced by the SNS –> nicotine activation of autonomic ganglia –>
    - NE released and binds with a1 –> contraction of blood vessel = increase blood pressure
  2. cardiac muscle tissues only modulated by autonomic inputs –> conflicting info from both SNS and PSNS postganglionic fibers will cause arrhythmias
    - NE released in SNS binds with b1 –> increase heart rate
    - Ach released in PSNS binds with M2 –> decreases HR
41
Q

heart receives input from SNS and PSNS. what is the actual difference btw sympathetic and parasympathetic divisions at synapse btw neurons and cardiac muscle?

A
  • SNS –> NE –> adrenergic receptors
  • PSNS –> Ach –> muscarinic receptors
  • which receptors are bound is the signal that determines how the heart responds
42
Q

adrenal medulla is a ____________ tissue. is also a modified _________ ____________
- innervated by sympathethic or parasympathethic preganglionic fibers?
- postganglionic neurons (_________ cells) lack ______ –> secrete (which neurotransmitter) into the _______

A
  • neuroendocrine tissue + modified sympathetic ganglion
  • sympathethic preganglionic fibers
  • chromaffin cells lack axons –> secrete mostly epinephrine (75%) into the blood
43
Q

where is the adrenal gland?

A

above the kidney

44
Q

somatic motor pathway consists of how many neurons?
- originates in _____ –> in (2)
- always inhibitory or excitatory?
- terminal branches close/far to target and each terminal innervates what?

A
  • 1 neuron!
  • CNS: brain and ventral horn of spinal cord
  • always excitatory –> EPP!
  • close to target –> each terminal innervates a single skeletal muscle fiber
45
Q

which enzyme is on end plate/in synaptic cleft of a neuromuscular junction?

A

achetylcholinesterase (AChE)

46
Q

M subtype nicotinic receptors :
- ________ -gated channels with (#) bindings sites for ________
- always excitatory/inhibitory –> creating what?

A
  • chemically gated with 2 binding sites for ACh
  • excitatory! creating muscle contraction –> 1 AP in neuron induces 1 AP on target muscle
47
Q

what is the motor end-plate?

A

region of muscle membrane that contains high concentrations of ACh receptors

48
Q

somatic motor neurons:
1. AP arrives at axon terminal –> causing what?
2.
3.
4.
5. depolarization of post-ganglionic cell
6. what happens to the neurotransmitter?

A
  1. AP arrives at axon terminal –> causing voltage-gated Ca2+ channels to open
  2. Calcium entry causes synaptic vesicles to fuse with presynaptic membrane –> releases ACh into synaptic cleft
  3. Nicotinic cholinergic receptors (Nm) binds 2 ACh molecules, opening non-specific monovalent cation channels
  4. Open channel allows Na+ and K+ to pass
  5. Net Na+ influx depolarizes muscle fiber
  6. ACh is metabolized by acetylcholinesterase
49
Q

somatic motor pathways:
signals come from:
- upper motor neurons via _________ tracts
- _______ ________ –> helps with muscle tone
- ___________ –> coordination
- sensory neurons or interneurons via __________

A
  • corticospinal tracts
  • basal ganglia helps with muscle tone
  • cerebellum –> coordination
  • via reflexes!
50
Q

impulses from somatic motor pathways activate lower motor neurons (cell bodies in what?)
- axons –> ______ _____ –> ________ nerve –> ______ –> voluntary movement

A
  • lower motor neurons
    *cell bodies in anterior gray of spinal cord
  • axons –> ventral root –> spinal nerve –> muscle –> voluntary movement
51
Q

primary motor cortex:
- 2 tracts come out of it?
- where do each go to? control what part of body?
- the second one has 2 different tracts: explain

A
  • cortico bulbar tract –> goest to brain stem (doesn’t go to spinal cord) –> where they interact with 2° neuron –> controls neck, face, head, skeletal muscles
  • corticospinal tract –> goes to spinal cord –> controls everything below brain stem –> passes through pyramid where it separates into:
    1. right anterior corticospinal tract –> small amount controlled –> go on same side until spinal cord –> crossover at spinal cord + interact with 2° neuron
    2. left lateral corticospinal tract –> major one! most muscles controlled by it –> crossover at medulla –> interact with 2° neuron –> to skeletal muscle

Mammalian physiology (13 decks)

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