DSA: Autonomy

Question 1

Describe a simple reflex arc involving skeletal muscle

Answer 1

1. Afferent (sensory) stimulus detects unexpected stretch of a muscle
2. Sends signal to muscle spindle located in the dorsal root ganglion of the spinal cord–> ventral root
3. Synapse on alpha-motor neuron of stretched muscle
4. FIRES
5. Release ACh at the NMJ
6. Causes contraction (shorterning of the stretched muscle

Question 2

Did we use our brain for the reflex arch involving the skeletal muscle?

Answer 2

No.

Question 3

In the autonomic NS, sensory information tells our body what?

Answer 3

When there is a change in our homeostasis.

Question 4

Are we aware of the of the stimulus that activates our ANS?

Answer 4

No.

But ones that are, we do not control the responses.

Question 5

What are sensory stimuli that can modify our ANS?

Answer 5

BP, PaO2, pH.

Question 6

What controls the activation of somatic reflexes?

Answer 6

Any level of the CNS: but many of them are generated in the spinal cord.

Question 7

What controls the activation of the ANS?

Answer 7

Lower levels of the brain: medulla–> hypothalamus.

Question 8

Efferent (motor) neuron in the somatic reflex is made up of how many neurons?

Answer 8

1 alpha-motor neuron

Question 9

Efferent (motor) neuron in the ANS is made up of how many neurons?

Answer 9

2: pre-ganglionic and post-ganglionic

Question 10

How does your sympathetic NS respond to stimuli?

Answer 10

1. Increase O2 to the “right” parts of the body by [increase HR and blood flow]
2. Increase glucose;

• [liver]–> glucose to the blood for use by skeletal muscles.
• Other less important tissue will use FFA.

3. We need to be able to clearly identify threats and responses
   - control focus and pupil (dilate)

Question 11

How does your parasympthatetic NS respond to stimuli?

Answer 11

1. Decrease O2 and decrease HR
2. Sends blood to digestive tract
3. Increase digestion
   - Glands in GI tract–> secrete enzymes/electrolytes
   - Increases instestinal motility
   - Relax sphincters so contents can from one part of the digestive tract to the other
4. Store NRG
   - Liver–> store glucose; decrease ability to release
   - Adipose tissue–> store FFA

Question 12

What are functions of the parasympathetic NS?

• Pupils
• Saliva production
• HR
• Bronchi
• Digestive organs
• Bladder-

Other?

Answer 12

1. Constricts pupils
2. Increase saliva production
3. Decrease HR
4. Constricts bronchi
5. Stimulates digestive organs, pancreas, bladder
6. Causes erection

Question 13

What are functions of the sympathetic NS?

• Pupils
• Saliva production
• HR
• Bronchi
• Digestive organs
• Bladder-

Other?

Answer 13

1. Dilates pupils
2. Decreases saliva production
3. Increases HR
4. Dilates the bronchi
5. Inhibits digestive organs, pancreas and gallbladder
6. Relaxes bladder
7. • adrenal medulla release of NE and EPI
8. Stimulates orgasm

Question 14

Describe the pathway of parasympathic NS and sympathetic NS

Answer 14

Question 15

Post-ganglionic neurons in the sympathetic NS bind to what type of receptors?

Answer 15

Adrenergic

Question 16

How are post-ganglioic cells different from pre-ganglionic cells?

Answer 16

Post-ganglioni cells have swellings called varisosities along the axon that allow the release of NT.

Question 17

Describe the synaptic cleft of post-ganglionic cells?

Answer 17

Larger, more open to the interstitial fluid because it does not make direct contact with the target organ. Thus, receptors for NT are distributed along the target organ

Question 18

What are the effects of the synaptic cleft of the post ganglionic cells being larger and more open? (3)

Answer 18

1. NT have to travel further,
2. More are detected in the blood
3. Receptors can be activated by NT that are diffused from original point of release.

Question 19

What type of receptors are adrenergic?

Answer 19

Metabotropic (serpentine)– > thus they + 2nd messengers

Question 20

What type of receptors do post-ganglionic neurons in the parasympathetic NS bind to?

Answer 20

Muscarinic, which are metabotropic.

Question 21

Muscarinic Gi receptors

Answer 21

Found on heart

Binding causes -AC–> - cAMP production–> increase K+ efflux from nodal cells–> decrease HR

Question 22

Muscarinic Gq recetors

Answer 22

Found on glands

+IP3 and DAG–> release of Ca2+

Question 23

The synapse between a neuron that traveled through the sympathetic chain and synapsed on a chromaffin cell in the adrenal medulla.

Answer 23

Nicotenic cholinergic

Question 24

Alpha-1 receptor activation

Answer 24

Causes radial muscles to contract–> dilates the pupil

Question 25

Beta-2 activation

Answer 25

ciliary muscles relax--\> [flattens lens]

Question 26

Beta-1 and Beta-2 activation

Answer 26

Increases HR and contraction

Question 27

Alpha-1 activation

Answer 27

Vasoconstriction--\> increases BP

Question 28

Beta-2 activation

Answer 28

Bronchodilation

Question 29

Are SNS and PNS an off an off switch?

Answer 29

No. They work together and can work at the same time.

Question 30

Which receptor increases stroke volume and heart rate?

Answer 30

Beta 1 adrenergic

Question 31

Which receptors constrict smooth muscle, as a general rule?

Answer 31

Alpha adrenergic

Question 32

Which receptors increase glandular secretions in the lungs?

Answer 32

Beta adrenergic

Question 33

What regions of the heart are affected by beta 1 receptors?

Answer 33

AV / SA node