Lecture 3-4

Question 1

What are the two types of depressor reflexes?

Answer 1

Baroreceptors and cardiac receptors

Question 2

What are the two types of excitatory reflexes?

Answer 2

Chemoreceptors and muscle work receptors

Question 3

What is the controlled variable? In reflex control

Answer 3

Blood pressure

Question 4

What are the two structures found within the medulla oblongata?

Answer 4

Nucleus ambiguous and nucleus tractus solitartius

Question 5

What is the nucleus ambiguous?

Answer 5

Origin of the vagus nerve

Question 6

What does the nucleus ambiguous do?

Answer 6

It has an inhibitory effect on the heart, acting on the relapse of ACH and acting on the muscarinic effectors

Question 7

What is the nucleus tractus solitartius important for?

Answer 7

Connections to the nucleus ambiguous

Question 8

What do baroreceptors do?

Answer 8

Give information about pressure

Question 9

What do the connections in the baroreceptors do?

Answer 9

Have connections that go up into the brain stem to go into the nucleus tractus and simulates and fire impulses into the nucleus tractus

Question 10

What is the cycle of the reflex loop?

Answer 10

Baroreceptors, nucleus tractus, nuelcus ambiguous, vagus nerves, release of ACh to muscarinic receptors

Question 11

What is the vagus nerve part of?

Answer 11

Cranial nerves

Question 12

Describe the vagus nerve

Answer 12

A nerve that originates from the brain stem region and comes out of the cranium and comes down into the rest of the body 10th cranial nerve

Question 13

What number is the vagus nerve in regards to cranial nerves?

Answer 13

10th

Question 14

What are CVLM and RVLM useful for?

Answer 14

Areas of the brain stem that are responsible for sympathetic outflow

Question 15

Describe RVLM

Answer 15

Output of the sympathetic nervous system, goes to the ganglia alongside the spinal chord

Question 16

What is the end goal for the sympathetic nervous system?

Answer 16

Increase heart rate and contractility

Question 17

Describe the CVLM

Answer 17

Connected between the RVLM and is an inhibitory mechanism which reduces the release of adrenaline - wont get an increase heart rate or contractility.
REDUCES heart rate

Question 18

Where are the majority of the baroreceptors located?

Answer 18

In the aortic arch

Question 19

Where else are baroreceptors located?

Answer 19

Carotid artery

Question 20

What happens to the carotid artery as it get’s higher?

Answer 20

Splits into two - has an external and internal carotid artery

Question 21

What is found at the start of the internal artery?

Answer 21

Some swelling and its known as the carotid sinus

Question 22

What happens at the carotid sinus?

Answer 22

There is high contraction of baroreceptors

Question 23

How are baroreceptors connected?

Answer 23

Connected through to the brain by nerve connections

Question 24

What are afferent fibres?

Answer 24

Take information into the brain

Question 25

What are efferent nerve fibres?

Answer 25

Nerves leaving the brain and They take information to the organs

Question 26

How are the carotid sinus baroreceptors connected through the cranial nerve?

Answer 26

By the 9th cranial nerve called glossypharyngeal nerve

Question 27

What type of receptors are baroreceptors?

Answer 27

They are stretch receptors, and are mechanoreceptors embedded in the wall of the artery

Question 28

Describe stretch receptors?

Answer 28

As blood pimps through the carotid sinus it stretches and that stretches the baroreceptors, stretching of wall increases firing rate

Question 29

What happens if you stopped the carotid sinus from stretching?

Answer 29

You wont get firing as the baroreceptors no longer respond to changes in pressure

Question 30

What happens if pressure increases?

Answer 30

You get more firing

Question 31

What is the maximum sensitivity?

Answer 31

Change in number of impulses/ change of pressure

Question 32

In regards to Pulsatile pressure, when a curve shifts to the left what does it mean?

Answer 32

It is more sensitive

Question 33

What are baroreceptors more sensitive too?

Answer 33

Pulsatile changes because that is how blood flows

Question 34

What do some baroreceptors have that some don’t?

Answer 34

Myelinated fibres

Question 35

What happens if you get the sinus nerve?

Answer 35

There will be no connection between the baroreceptors and the brain stem - decreases blood pressure

Question 36

What do increases carotid sinuses pressure lead to?

Answer 36

Decrease in blood pressure

Question 37

What does decreases carotid sinus pressure lead to?

Answer 37

Increases blood pressure

Question 38

Do you need both sets of baroreceptors in the aortic and carotid sinuses?

Answer 38

No the carotid sinus baroreceptors are probably the most important in maintaining blood pressure

Question 39

What are some mechanisms that the baroreceptors use to adjust blood pressure?

Answer 39

Central resting, peripheral resetting and resetting in hypertension

Question 40

Does the baroreceptors reflex happen all the time?

Answer 40

No, if it was working all the time you wouldn’t be able to do activity therefore central resetting is used to rest the baroreceptors

Question 41

What is an example of resetting in baroreceptors?

Answer 41

When you exercise, the central resetting system known you are exercising and so it changes the way baroreceptors are responding and the sensitivity of the baroreceptors are adjusted

Question 42

What happens if there is a change in blood pressure in the peripheral reset system?

Answer 42

If BP decreases the baroreceptors become more sensitive and causes vasodilation, if there is an increase in BP the baroreceptors become less sensitive and vasoconstriction occurs

Question 43

Hypertensive =

Answer 43

More sensitive

Question 44

Hypotension =

Answer 44

Less sensitive

Question 45

Describe hypertension baroreceptors reset

Answer 45

Baroreceptors become less sensitive, and function at a less sensitive rate then with low pressure

Question 46

What are baroreceptors main job?

Answer 46

To smooth out blood pressure and allows us to sit down and stand up at keep blood pressure at a maintained range

Question 47

What happens to BP when you take baroreceptors away?

Answer 47

You have a much broader arterial pressure

Question 48

What system do baroreceptors act as?

Answer 48

A buffering system - reduce the blood pressure in daily events when you change posture, respiration or excitement

Question 49

What do cardiopulmonary receptors do?

Answer 49

Similar job to baroreceptors, but have a structural difference, they fine tune the system

Question 50

What is the structural difference between cardiopulmonary receptors and baroreceptors?

Answer 50

Cardiopulmonary receptor have 80% afferent and have a small diameter with unmyelinated fibres

Question 51

What do cardiac mechanoreceptors do?

Answer 51

Give information about pressure changes in the chambers of the heart itself

Question 52

Where are cardiac mechanoreceptors located?

Answer 52

Around the right atrium and the vessels that bring blood to the heart (around the atrial tissue) and pulmonary veins

Question 53

What does type A respond to?

Answer 53

Atrial systole

Question 54

What does type B respond to?

Answer 54

V wave of atrial filling

Question 55

What feedback to cardiac mechanoreceptors demonstrate?

Answer 55

Information about venous pressure and cardiac filling

Question 56

What do veno-atrial stretch receptors do?

Answer 56

Detect changes in cardiac blood volume

Question 57

Describe the brain bridge reflex

Answer 57

Controls heart rate in response to blood volume

Question 58

What do chemoreceptors do?

Answer 58

Give information into the cardiovascular system about different factors that affect the system

Question 59

Where are peripheral chemoreceptors found?

Answer 59

In the aortic and carotid bodies

Question 60

What is the aortic body innervated by?

Answer 60

By the aortic nerve (a branch of the vagus)

Question 61

What do peripheral chemoreceptors primarily regulate?

Answer 61

Respiration rate (PCO2)

Question 62

What do peripheral chemoreceptors support?

Answer 62

Blood pressure when baroreceptors reflex out of range, less than 70mmHg

Question 63

What are the reflex effects that peripheral chemoreceptors respond to?

Answer 63

Vasoconstriction of arterioles and venoconstriction, tachycardia

Question 64

What do mechanoreceptors (myelinated) do?

Answer 64

Target the reflex effect of tachycardia and are stimulated by local pressure and muscle contraction

Question 65

What are chemoreceptors (metaboreceptors, unmyelinated) activated by?

Answer 65

By chemicals release during exercise e.g. K+, H2PO4-. H+ and ATP

Question 66

What are the reflex effects of chemoreceptors?

Answer 66

Increased sympathetic flow, tachycardia and increase YPT

Question 67

What are mechanoreceptors and chemoreceptors both blocked by?

Answer 67

Local anaesthetic to muscle nerves

Question 68

Describe syncope

Answer 68

A sudden, transient loss of consciousness and postural tone, with spontaneous recovery - sitting down to stranding up

Question 69

What is the mechanism for syncope?

Answer 69

Transient global hypoperfusion

Question 70

What generation is syncope common In?

Answer 70

All ages groups but particular elderly

Question 71

What is nuerocardiogenic syncope?

Answer 71

An autonomically mediated reflex mechanisms associated with inappropriate vasodilation or bradycardia causing syncope

Question 72

What is the most common type of neurocardiogenic syncope?

Answer 72

Vasovagal syncope

Question 73

What does vasovagal syncope mechanisms involve?

Answer 73

Pathophysiological autonomic reflex, with triggering factors, modulating factors and afferent pathways

Question 74

What are some warning signs of the vasovagal response?

Answer 74

Nausea, warmth and lightheadedness

Question 75

What is the vasovagal response?

Answer 75

An inappropriate vessel dilation and bradycardia response leading to reduced cerebral perfusion and syncope