VI Blood circulation

Question 1

What type of receptors do epinephrine act on?

Answer 1

Mainly beta but also alpha receptors. The distribution of the adrenergic receptors and their sensitivity is tissue specific

Question 2

What effect does acetylcholine have on blood pressure?

Answer 2

It decreases blood pressure because it sets free nitric acid and inhibits cardiac activity

Question 3

What causes vagus apnoea?

Answer 3

Stimulating the vagus, due to the hering-breuer reflex

Question 4

How does the pressor area act?

Answer 4

Spontaneous activity, acts by stimulating the thoracolumbar sympathetic preganglionic and postganglionic neurons. It had positive chrono, dromo, bathmo and inotrop effect of the heart

Question 5

What happens if the depressor area is stimulated?

Answer 5

A drop in blood pressure via the vagus nerve. Has a negative dromo, bathmo, chrono and inotrop effect on the heart.

Question 6

The vasomotor centers respond to changes in blood pressure level by altering the ___ (1) (direct effect) or __ (2) (negative effect on the heart)

Answer 6

1 - sympathetic

2 - parasympathetic (vagal)

Question 7

What receptors do epinephrine effect?

Answer 7

Beta 2 adrenergic receptors and alpha 1 as well

Question 8

Why does acetylcholine decrease blood pressure?

Answer 8

Sets free nitric acid and inhibits cardiac activity

Question 9

The 2 centers in the pons?

Answer 9

Pneumotaxic and apneustic

Question 10

Which part of the depressor nerve do you have to stimulate to cause vasodilatation?

Answer 10

Caudomedial depressor area

Question 11

The vasomotor centre is located close to the respiratory centers in the …?

Answer 11

Reticular formation

Question 12

What happens when the basal tone or vasoconstrictor tone decreases?

Answer 12

The blood vessel diameter increases, which results in higher perfusion

Question 13

Large arteries

Answer 13

135/68 mmHg

Question 14

Where can the chemoreceptors be found?

Answer 14

In the CNS at the bottom of the fourth ventricle, and in the peripheral circulation in the carotid body and aortic body

Question 15

What happens to respiration when vagus nerve is stimulated?

Answer 15

Irregular respiration

Question 16

Aorta

Answer 16

120/75 mmHg

Question 17

Is the intrinsic regulation dependent on the nervous system?

Answer 17

No

Question 18

Where are chemoreceptors located in the CNS?

Answer 18

At the bottom of the fourth ventricle

Question 19

What does VRG stand for and what does it contain?

Answer 19

Ventral respiratory group and it contains both inspiratory and expiratory neurons

Question 20

Afferent nerve of the Hering-Breuer reflex?

Answer 20

Vagus nerve

Question 21

Where are the vasomotor centers located in the brain?

Answer 21

Close to respiratory centre in the reticular formation

Question 22

What do the peripheral chemoreceptors monitor?

Answer 22

Changes in partial pressure of oxygen

Question 23

Which vasomotor centre shows spontaneous activity?

Answer 23

Pressor area

Question 24

What is the range of which baroreceptor mechanisms function?

Answer 24

50-170 mmHg

Question 25

Pulmonary artery

Answer 25

23/9 mmHg

Question 26

Where does the depressor area receive information from?

Answer 26

Peripheral receptors. It has no spontaneous activity

Question 27

EDRF

Answer 27

Endothelium derived relaxing factors

Question 28

Bayliss effect

Answer 28

The Bayliss effect in vascular smooth muscles cells is a response to stretch. This is especially relevant in arterioles of the body. When blood pressure is increased in the blood vessels and the blood vessels distend, they react with a constriction; this is the Bayliss effect. Stretch of the muscle membrane opens a stretch-activated ion channel. The cells then become depolarized and this results in a Ca2+ signal and triggers muscle contraction. It is important to understand that no action potential is necessary here; the level of entered calcium affects the level of contraction proportionally and causes tonic contraction

Question 29

Stimulating the ___ (1) area and the ___ (2) area causes vasoconstriction and vasodilatation respectively

Answer 29

1 - craniolareral pressor area | 2 - caudomedial depressor area

Question 30

What happens when the vagus nerve is stimulated?

Answer 30

Blood pressure drop

Question 31

Blood flow velocity capillaries

Answer 31

0.05 cm/sec

Question 32

What is an important requirement for the Bayliss effect?

Answer 32

The metabolic demand of the organ has to remain constant

Question 33

Large veins

Answer 33

2-5 mmHg

Question 34

Left ventricle

Answer 34

120/8 mmHg

Question 35

End of arteries

Answer 35

90/68 mmHg

Question 36

What are baroreceptors and where are they found

Answer 36

They are stretch receptors and they are mostly found in the aortic arch and the carotid sinus

Question 37

Which afferent nerve transfers stimuli from n.vagus to bronchopulmonary centre?

Answer 37

Expiratory neurons from pons respiratory group

Question 38

Where are the expiratory neurons located in the brain stem?

Answer 38

Ventral respiratory group (VRG)

Question 39

Extrinsic (central) control involves ...?

Answer 39

Nervous and humoral effects, reflex reactions and morphological changes

Question 40

Which area of the brain show spontaneous sympathetic activity?

Answer 40

The pressor area

Question 41

Increased pressure in the smooth muscle of the arterioles elicit ...?

Answer 41

Contraction

Question 42

What vessels don’t contain parasympathetic innervation?

Answer 42

Skin and skeletal muscle resistance vessels

Question 43

Pulse wave velocity

Answer 43

7 m/sec

Question 44

What determines the actual diameter of the vessels?

Answer 44

A balance between the sympathetic vasoconstrictor tone and the locally produced nitric oxide by the endothelial cells

Question 45

What are the most important humoral factors affecting humoral control of blood pressure?

Answer 45

Adrenal hormones

Question 46

Decreased pressure in the smooth muscle of the arterioles elicit ...?

Answer 46

Relaxation

Question 47

Venous end of capillaries

Answer 47

10 mmHg

Question 48

The vagus nerve transfers signals from ___ to the respiratory centers

Answer 48

Bronchopulmonary stretch receptors

Question 49

The baroreceptors in the aa have their afferents in ___ (1) and the ones in the cs have their afferents in the ___ (2)

Answer 49

1 - N. Vagus (X) | 2 - Herings nerve (a branch of IX)

Question 50

What does the intrinsic (local) regulation do to the vessels?

Answer 50

Dilate the diameter

Question 51

Where are the centers responsible for the control of circulation located?

Answer 51

Brain stem

Question 52

What does the pontine respiratory group involve?

Answer 52

The pneumotaxic centre which facilitates expiration and the apneustic centre which facilitates inspiration

Question 53

What happens to the blood vessels for the EDRF and the EDCF to be produced?

Answer 53

Blood pressure deforms the endothelial cells

Question 54

What two ways inhibit the inspiration? What is this phenomenon called?

Answer 54

1. Stimuli from the bronchopulmonary stretch receptors excite the expiratory neurons and the pontine respiratory group 2. These stimuli inhibit the inspiratory neurons Called the inspiration inhibiting reflex of the n. Vagus or the Hering-Breuer reflex

Question 55

Lung capillaries

Answer 55

23/9 mmHg

Question 56

What depends on the myotonic control of the diameter of arterioles and metarterioles in the microcirculatory bed?

Answer 56

Short term intrinsic control

Question 57

Increasing stimulation of volume receptors lead to increasing ...?

Answer 57

Depressor activity which leads to vasodilatation (blood pressure drop)

Question 58

Which stump of the depressor nerve do you stimulate to decrease blood pressure?

Answer 58

Vagus nerve

Question 59

What happens to the vessels after denervation?

Answer 59

The vasoconstrictor tone disappears completely, the remaining tone is called basal tone and is caused by the spontaneous depolarization of smooth muscles

Question 60

Impulses transmitted by chemoreceptors induce rapid changes in ...?

Answer 60

Ventilation | pCO2 increase and pO2 decrease = sympathetic activation

Question 61

EDCF

Answer 61

Endothelium derived contraction factors

Question 62

What does the Goltz experiment elicit and what does it stimulate

Answer 62

It elicits the carotid sinus reflex and stimulates the vagus, depressor and sympathetic nerves

Question 63

Where can you find the respiratory center/neurons?

Answer 63

Brain stem, pons close to the vasomotor center in the reticular formation

Question 64

Which part of the depressor nerve do you have to stimulate to cause vasoconstriction?

Answer 64

Craniolateral pressor area

Question 65

Blood flow velocity aorta

Answer 65

30-40 cm/sec

Question 66

What nerve is different in rabbits and what is it called? (In relation to baroreceptors)

Answer 66

Herings nerve is a separate nerve in rabbits and is called n.depressor

Question 67

Blood flow velocity large veins

Answer 67

15-20 cm/sec

Question 68

What two things have to happen in parallel to inhibit inspiration?

Answer 68

Stretch receptors have to be activated parallel to airway distention

Question 69

What do the Traube-Hering waves show and how are they obtained?

Answer 69

They show the inborn changes in the tone of the respiratory and vasomotor centers. They are obtained by connecting the lowermost points of the respiratory wave.

Question 70

What effect does short term stimulation of the vagus nerve have on the blood pressure?

Answer 70

Heart rate decrease, blood pressure decrease for a while

Question 71

What nerve ha the afferent fibers from baroreceptor in the carotid sinus?

Answer 71

Herings nerve

Question 72

Where are the volume receptors found?

Answer 72

In the lungs and the capacitance system of circulation (e.g. th right atrial wall)

Question 73

What are the reflex mechanisms based on?

Answer 73

Afferent information supplied by baro-, volume-, and chemoreceptors

Question 74

What can the Goltz experiment examine.

Answer 74

The neural factors controlling blood pressure and respiration

Question 75

What is the role of the apneustic center?

Answer 75

Inspiration

Question 76

Arterial end of capillaries

Answer 76

32 mmHg

Question 77

Which nerve is afferent from the heart?

Answer 77

N vagus

Question 78

Left atrium

Answer 78

6 mmHg

Question 79

What happens if you compress the carotid artery cranial to the carotid sinus?

Answer 79

Increase blood pressure

Question 80

What is the effect of compressing both left and right vagus nerve?

Answer 80

Respiration stops, then deeper and less frequent respiration, heart rate increases

Question 81

Right atrium

Answer 81

3 mmHg

Question 82

Where is the nuclei for the phrenic nerve located?

Answer 82

In the spinal segment of C4 (mainly inspiratory)

Question 83

What happens if you compress the carotid artery caudal to the carotid sinus?

Answer 83

Slow increase in systemic blood pressure

Question 84

What do the central chemoreceptors monitor?

Answer 84

The pH as well as the partial pressure of CO2 of the blood and cerebrospinal fluid

Question 85

Right ventricle

Answer 85

25/0

Question 86

Right ventricle

Answer 86

25/0