Unit 7 autonomic nervous system

Question 1

Peripheral nervous system subdivision

Answer 1

Somatic ns (voluntary actions) and autonomic ns ( involuntary)

Question 2

Autonomic 2 subdivision

Answer 2

Parasympathetic psns (rest and digest): relaxing

Sympathetic sns (flight/fight): exercise, stress/scared

Question 3

Homeostasis between psns and sns

Answer 3

When sns activity high, psns activity low vice versa

Question 4

Autonomic nervous system pathway (preganglionic and postganglionic)

Answer 4

From cns to effectors

Composed of 2 multipolar neurons

Preganglionic= first in pathway, myelinated (from brain/spinal, to ganglion)

Post= 2nd in path, unmyelinated, from ganglion to smooth muscle

Question 5

A toxin that destroys varicosities in nervous system will

Answer 5

Prevent stimulation of sweat glands

Decrease release of neurotransmitters from postganglionic neurons

Question 6

Similarity between somatic and autonomic pathways

Answer 6

Acetycohaline is secreted from the neuoron that originates in the cns

Question 7

Ending signalling by the neurotransmitter at the majority of sympathetic neuroeffector junctions:

Answer 7

Diffusion of norepinephrine away from the target cell

Breakdown of norepinephrine by MAO in the varicosity

Question 8

neuroeffector junction

Answer 8

synapse between postganglionic neurons and effectors facilitated by varicosities (expanding axon terminals like beads on a string)

Question 9

sympathetic nervous system (flight/fight):
1. location of cell bodies of preganglionic neurons,
2. location of autonomic ganglia
3. lengths of fibers
4. neurotransmitters released

Answer 9

1. lateral horn in spinal cord of thoracic and spinal regions
2. sympathetic chain ganglia and collateral ganglia
3. pre fibers= short and axon terminal release acetylcholine
   post fibers=long, and its axon terminal release NE

Question 10

parasympathetic nervous system (rest and digest):
1. location of cell bodies of preganglionic neurons,
2. location of autonomic ganglia
3. lengths of fibers

Answer 10

1. brainstem nuclei and lateral horn of spinal cord in sacral region
2. terminal ganglia (outside or inside wall of organ/effector)
3. pre fibers= long post fibers= very short

Question 11

sns vs psns: neurotransmitter, receptor, synthesized from, varicosity membrane transfer for:

Answer 11

NE, Ach

alpha and beta adregernic, nicotinic and mosaninic

tyrosine, acetyl coA and choline

NE, choline

Question 12

neurotransmitters (Ach)

Answer 12

released by preganglionic neurons, targets nicotinic receptors (NN) on postganglionic cells and chromatin cellsin the adrenal medulla

Question 13

neurotransmitters (NE)

Answer 13

released by postganglionic neurons, interacts with alpha,beta adregernic receptors of the effector membrane

Question 14

Sweat glands

Answer 14

Postganglionic neurons release Ach which activates M3 muscarinic receptors

Question 15

pathway

Answer 15

1. arrival of AP at the varicosity
2. depolarization leading to opening 3 at the voltage ca channels
3. Ca into cell
4. exocytosis of NE facilitated by ca++
5. NE crossing synaptic cleft to bind with adrenergic receptors (GPCR’s) on effector cells
6. signal transduction occurs within the effector cell

Question 16

SNS= longer lasting effects than psns because:

Answer 16

1. Ach released by postganglionic PSNS neurons quickly degraded by Ach
2. mechanisms to. remove/degrade NE from synapse are slower (NE is there longer)

Question 17

Ach released by preganglionic neurons acts on…

Ach released by postganglionic neurons acts on…

Answer 17

Nn (N2) nicotinic receptors on the membrane of the postganglionic cell

muscarinic receptors in the effector membrane

Question 18

Antagonist (opposite) effects

Answer 18

Common
Ex: heart
SNS heart rate up and force contraction via B adrenergic receptos

PSNS down heart rate and force of contraction via M2 Musurinic receptors

Question 19

Synergistic effects (- sns and psns similar effects)

Answer 19

rare
Ex: salivary glands- both sns and psns stimulate secretions from salivary glands but:

Sns stimulates alpha and beta receptors for secretion of thick mucus

Psns stimulates muscarinic receptors that cause secretion of watery enzyme rich saliva

Question 20

Complementary effects (opposite effects)

Answer 20

Rare
Ex: male reproduction response

Question 21

Exampes of single innervation by ans

Answer 21

Adrenal medulla and sweat glands (sns only)

Question 22

Give example of how hypothalamus dont need input for its ans functions but emotions cause autonomic effects

Answer 22

Blushing when embarrassed, sweat when nervous