Neuroscience Week 5: Autonomic Reflexes and Integration

Question 1

Objectives

Answer 1

Question 2

“Fight or flight” and “Rest and digest”

are limited

Answer 2

Question 3

Simple muscle reflex

Answer 3

Question 4

Examples of Autonomic Reflexes and Disorders

4 listed

Answer 4

Question 5

Baroreceptor Reflexes: monitoring of blood pressure

Answer 5

monitoring of bp: aortic arch and carotid sinus

Question 6

Baroreceptors: Carotid Sinus sensory nerves

Answer 6

Question 7

Baroreceptors: Aortic arch sensory nerves

Answer 7

Question 8

Baroreceptors: Control center

Answer 8

information integrated in the medulla

Question 9

Baroreceptor activity

Answer 9

• as blood pressure drops, baroreceptor firing frequency decreases
• as blood pressure rises, baroreceptor firing frequency increases

Question 10

Baroreceptor Reflex loop

Answer 10

Question 11

Baroreceptor effector responses: In response to inappropriate decreased blood pressure

Answer 11

Sympathetic response:

• Norepinephrine acting on α1-receptor causing ↑ PLC and β1 causing adenylate cyclase ↑
• also sympathetics through chromaffin cells in the adrenal medulla

Question 12

Baroreceptor effector responses: In response to inappropriate increased blood pressure

Answer 12

Parasympathetic response:

• Acetylcholine on M₂ receptors
• and
• reduced sympathetic activation

to ↓Heart rate and ↓peripheral resistance

Question 13

Baroreceptor Reflex Summary

Answer 13

Question 14

Complexities of predicting effects of adrenergic drugs

Answer 14

Question 15

Baroreceptor Reflex response to Pentolamine

Answer 15

• α1-adrenergic receptor
• baroreceptor reflex response causes strong increases in heart rate and cardiac output
• (activate strong sympathetic to vasculature activation but it won’t do anything because it is blocked)

but not blocking

• (activate strong sympathetic to the heart β1 and adrenals release epinephrine)

Question 16

Baroreceptor reflex parasympathetic effectors

Answer 16

Question 17

Baroreceptor reflex sympathetic effectors

Answer 17

Question 18

Bladder Filling and Emptying: Reflex contraction of the external sphincter

Answer 18

Spinal reflex with a somatic motor neuron - not autonomics

as the fundus gets more full there are stretch receptors which will then increase the amount of force of contraction of the external sphincter closure

Question 19

Bladder Filling and Emptying: Bladder Sympathetics

Answer 19

Question 20

Coordinated Bladder Filling and Emptying:

Answer 20

spinal reflex integrates with (ascending dorsal interneuron pathway) to turn on sympathetic activation of bladder control based on how full the bladder is

Question 21

Bladder Filling and Emptying: urination control system

Answer 21

parasympathetics

Question 22

Urinary parasympathetic pathway location and effects

Answer 22

Question 23

Coordinated Bladder Filling and Emptying: Urination control

Answer 23

• parasympathetics are also connected to the spinal nerve reflex
• the degree of force to expel when full or moderately full is different based on information from the spinal nerve root

Question 24

Coordinated Bladder Filling and Emptying: Complete

Answer 24

Question 25

Coordinated Bladder Filling and Emptying: Main control when deciding to urinate name & location

Answer 25

micturation center in the rostral pons

Question 26

Coordinated Bladder Filling and Emptying: Main control when deciding to urinate mechanism 4 steps

Answer 26

First: ascending input to the micturition center signals bladder distension

Question 27

Coordinated Bladder Filling and Emptying: Summary

Answer 27

Question 28

Thermoregulation: Sensors

Answer 28

* Hypothalamus (blood bathing) * thermosensitive fibers in the trunk sending information to the hypothalamus

Question 29

Thermoregulation: Heat conservation center effector responses 4 listed

Answer 29

Question 30

Thermoregulation: Heat conservation center effector responses (**Control**)

Answer 30

Question 31

Thermoregulation: Heat loss center effector responses 4 listed

Answer 31

Question 32

Thermoregulation: Heat loss center effector responses (**control**)

Answer 32

Question 33

Sympathetic effectors and receptors

Answer 33

Question 34

Thermoregulation: Hypothalamus nuclei

Answer 34

Question 35

Identify and function

Answer 35

Question 36

Hypothalamus Nuclei for cooling

Answer 36

Anterior hypothalamic area

Question 37

Hypothalamus Nuclei for heating

Answer 37

Posterior hypothalamic area

Question 38

Thermoregulation Summary

Answer 38

Question 39

What happens if anterior hypothalamic nuclei is damaged?

Question 40

What happens if posterior hypothalamic nuclei is damaged?

Question 41

What is this

Answer 41

inappropriate spasmodic vasoconstriction

Question 42

Nifedipine MOA

Answer 42

α1 blocker

Question 43

What autonomic system is involved here?

Answer 43

too much α1 activation

Question 44

Raynaud's disease Clinical Presentation

Answer 44

Question 45

Raynaud's disease Treatment

Answer 45

* α1 blocker useful * Smooth muscle blockers (nifedipine) can also be useful * Sympathectomy may reduce the frequency and duration of attacks, but usually reserved for very serious cases

Question 46

Sympathectomy

Answer 46

* not very common but has been done * takes out a lump of the sympathetic chain * T1 - T4 ganglia removal * A few patients developed Horner's Syndrome

Question 47

Horner's Syndrome: Which side is affected?

Answer 47

The side with the * pseudoptosis * Miosis * Enopthalmis * Anhidrosis * Dilation of the arterioles of the skin

Question 48

Horner's Syndrome: What is the effect of the lesion

Answer 48

Decreased sympathetic and unopposed parasympathetic

Question 49

Autonomic innervation of the eye

Answer 49

Question 50

Parasympathetics innervation of the eye

Answer 50

Question 51

Horner's Syndrome: Clinical Presentation

Answer 51

ipsilateral to the lesion

Question 52

What autonomic system can cause inappropriate pupil dilation

Answer 52

too much sympathetics and/or too little parasympathetics

Question 53

Horners Syndrome: What is the lesion and where is the lesion

Answer 53

Preganglionic or postganglionic would use a CT to try to figure it out or determine which nerves are affected and where?

Question 54

Horners Syndrome: Preganglionic common causes?

Answer 54

* Aortic Dissection * trauma * carotid dissection * tuberculosis * Pancoast tumor

Question 55

Horners Syndrome: Postganglionic common causes?

Answer 55

* trauma * cluster headache * neck or thyroid surgery

Question 56

Test for Horners Syndrome: in the eye

Answer 56

* if preganglionic is damaged but postganglionic is viable can test with drugs ectopically in the eye then can get a response * If the postganglionic neuron is damaged then no response to drugs because there is no epinephrine at the target neuron

Question 57

Integration and reflexes Summary

Answer 57

ALSO, APPLY SIMILAR REASONING TO OTHER ORGAN SYSTEMS

Question 58

Carotid baroreceptors travel with this nerve

Answer 58

Glosspharyngeal

Question 59

Aortic arch baroreceptors travel with this nerve

Answer 59

Vagus

Question 60

Nifedipine Therapeutic use

Answer 60

Raynaud's Disease