Autonomic CIS

Question 1

Sympathetic Nervous System uses which type of receptors?

Answer 1

Nicotinic, Alpha and Beta Adrenergic receptors

Question 2

Parasympathetic uses which type of receptors?

Answer 2

Muscarinic receptors

Question 3

What’s the first thing that happens in our body after we hear a gun shot?

Your sympathetic kicks in which increases what?

how do we get that first thing anyway?

Answer 3

the need for o2 to go to the tissue

B2 receptors help relax the lungs for bronchodilation.

Glands for secretion = Alpha receptors decrease secretion, B increase secretions. depends on the environment

Question 4

Once we have O2 in the blood, how do we get it to the tissues we need?

Answer 4

Through frequency:

Increase the activity of the SA/AV node –> Increases the activity of B1 receptors –> influences phase 4 (funny Na channels) which increases phase 4 slope so increase depolarization

Through stroke volume/CO

we have an increase in B1 receptors –> brings more Ca2+ into the myocyte which increases contractibility meaning a higher stroke volume / cardiac output.

Question 5

Once we’ve affected frequency and stroke volume and Cardiac output, what happens in the skeletal muscle?

Answer 5

Blood goes to the skeletal muscle –> Sympathetic activation increases –> B2 receptors on the vascular smooth muscle relax allowing for dilation and greater blood flow

Question 6

Once we’ve affected frequency and stroke volume and Cardiac output, what happens in the brain, heart, and lungs?

Answer 6

There is little to no sympathetic innervation.

blood flow is activity dependent (local control –> metabolic rate shows how much dilation there is)

Question 7

Once we’ve affected frequency and stroke volume and Cardiac output, what happens in the gut, kidney, skin, and salivary glands?

Answer 7

Alpha receptors are activated which promotes contraction and vasoconstriction.

This redirects blood to the skeletal muscle. which needs it the most.

Question 8

What’s the rule of thumb for receptors in the smooth muscle?

Answer 8

alpha constricts and causes contraction

b2 relaxes

Question 9

What happens when you HEAR a gun shot and turn your head to the sound?

Answer 9

your pupils dilate to get more light which is done by alpha 1 receptors that constrict the radial muscles of the eye

your ciliary muscle is relaxed to focus on far vision. this is done by increased activity of B2 receptors that flatten the lens and see the distance will increase

Question 10

What happens in the gut during a shooting and the sympathetic response?

Answer 10

Gastric motility lowers because we don’t want to send blood there. this is done by Beta receptors –> relaxes the smooth muscle

sphincters become more active because we don’t want to move food around, need to close that shut.. this is done by alpha receptors that constrict it.

secretion is lowered (we don’t need it) and this is done by alpha receptors

Question 11

What happens to our nutrients during a shooting in the…

Liver/skeletal muscle?

Fat?

Pancreas?

Answer 11

Liver: alpha and beta are activated to increase glycogenolysis. we want glucose only to go to the skeletal muscle

beta receptors are activated more leading to lipolysis so other cells can use the FFAs that are produced.

Pancreas lowers insulin due to the alpha receptors

Question 12

Explain the Myotatic stretch reflex

Answer 12

when the muscle stretches, the firing rate of the sensory fibers innervated by the muscle spindle increases in proportion to how much the muscle was st retched.

an afferent (sensory) stimulus triggers a motor response to contract it back.

it’s protecting our muscle from tearing

Question 13

What is the somatic reflex and what’s important about it?

Answer 13

sensory info relayed back to the spinal cord through dorsal root ganglion.

synapses on alpha-motoneuron of the stretched muscle. Brings the alpha motoneuron to threshold causing an AP, travels down the axon and releases Ach at the neuromuscular junction for the stretched muscle.

causes contraction to prevent damage to the muscle

IMPORTANT: doesn’t require the brain, only in the spinal cord

Question 14

Explain preganglionic characteristics for parasympathetic

sympathetic?

Answer 14

i. The neurotransmitter released by the pre-ganglionic fiber is acetylcholine
ii. Once released from the pre-ganglionic axon, the acetylcholine will diffuse across the synaptic cleft and bind with a nAchR on the post-ganglionic dendrite
iii. This allows sodium into the post-ganglionic cell and causes it to depolarize

exact same thing!

Question 15

What’s different about post-ganglionic for the parasympathetic and sympathetic

Answer 15

The synapse is VERY different than from other synapses, but the neurotransmitter release is IDENTICAL

instead of the axon terminating in the presynaptic terminal, the axon has several swellings

these are called VARICOSITIES

Question 16

Does the post-ganglionic axon make contact with anything?

What’s so special about this?

Answer 16

ii. the post-ganglionic axon doesn’t make a specialized contact with the target organ (in this case, smooth muscle)
1. the synaptic cleft is much larger

the neurotransmitter can diffuse quite some distance away from its release point and measurable amounts can be detected in the blood

receptors can be activated by some of the neurotransmitter that diffused away from the original point of release

Question 17

Explain the postsynaptic parasympathetic division?

Answer 17

synapse between the parasympathetic post-ganglionic neuron and the target cell is similar to synapse #1 in that ACETYLCHOLINE is released from the post-ganglionic neuron’s varicosities

the receptor that the acetylcholine binds to is a MUSCARINIC ACHR, NOT N-ACHR

Binding of the muscarinic receptor causes a second messenger system, G protein type of second messenger

Question 18

Explain the postsynaptic sympathetic division!

Answer 18

1. The neurotransmitter released by the post-ganglionic axon is Norepinephrine
   a. Two general categories of adrenergic receptors that they bind to are Alpha and Beta receptors

Question 19

What happens in the adrenal medulla?

Answer 19

Sympathetic preganglionic fibers leave the spinal cord, pass through the sympathetic chain and travel to the adrenal medulla

i. They synapse on the chromaffin cells
ii. These chromaffin cells release epinephrine
iii. The epinephrine in the blood then does the same thng as norepinephrine but different affinity.