3.4 Cardiovascular Regulation Flashcards Preview

AA > 3.4 Cardiovascular Regulation > Flashcards

Flashcards in 3.4 Cardiovascular Regulation Deck (39):
1

Two levels of regulation

1) Local: occurs within the tissue
2) Non-local: maintaining body-wide MAP

2

Local control of blood flow through capillaries

Controlled by ARTERIOLES

3

What causes vascular smooth muscle relaxation (local control through capillaries)

Local increases in metabolites generated as waste products of anaerobic cellular respiration / decreases in nutrients

4

What happens after vascular smooth muscle dilation? (local control through capillaries)

Dilation and increased blood flow (Active hyperemia)

5

What does increased dilation and blood flow do?

Reduces SVR if widespread

6

Metabolites with vasodilatory effects

CO2, lactic acid, O2, glucose

7

A(n) ______ in CO2 and lactic acid (decrease in pH) would lead to vasodilation

Increase

8

A(n) ______ in O2 or glucose would lead to vasodilation

Decrease

9

Mechanism of local control though capillaries

Vasodilation follows endothelial cells release of NO (nitric oxide)

10

Essential sensory receptors in cardiovascular reflexes

-Baroreceptors
-Chemoreceptors

11

Baroreceptors

Stretch receptors monitor pressure in large arteries

12

Chemoreceptors

Detect pH (indirectly CO2, O2) in carotid and aortic bodies and medulla oblongata

13

What is the signal integrator of cardiovascular reflexes?

Cardiovascular center in medulla

14

Effectors of cardiovascular reflexes

1) Heart
2) Vascular smooth muscle

15

What does the heart control in terms of blood regulation?

Cardiac output (both HR and SV)

16

What does vascular smooth muscle control in terms of blood regulation?

SVR and CO
Vasoconstriction / vasodilation
Venous return (impacts CO)

17

Vessels innervated by adrenergic fibers...

Vasoconstrict (e.g. vessels to skin, abdominal organs)

18

Vessels innervated by cholinergic fibers...

Vasodilate (e.g. vessels to skeletal muscles, coronary muscles)

19

Vessels innervated by cholinergic fibers...

Vasodilate (e.g. vessels to skeletal muscles, coronary muscles)

20

Two ways of maintaining MAP through cardiac output

-Intrinsic regulation
-Extrinsic regulation

21

Intrinsic regulation

Property of myocardium
Frank Starling Law of the Heart (blood pumps all of the blood that it receives)
-Dependednt on venous return

22

Extrinsic regulation

By ANS

23

How does the sympathetic nervous system increase CO?

Increases SV and HR

24

How does the sympathetic NS decrease CO?

Decreases HR

25

Frank Starling Law of the Heart

Increase in venous return -> Increase in end diastolic volume -> Increase in stroke volume

26

What underlies the Frank-Starling law?

Length-tension relationship in cardiac muscle

27

What does the parasympathetic nervous system use to decrease HR?

Acetylcholine (cholinergic / muscarinic receptors)

28

First way that Acetylcholine decreases HR

Increasing K+ currents
Hyper polarizes
-Pacemaker cells in SA node
-Conductive cells in AV node

29

Second way that acetylcholine decreases HR

Decreasing rate of Na+ leakage, slows the rate that the pacemaker cell reaches threshold

30

How much of an effect does the parasympathetic nervous system have on myocardial contractility (power of muscle contraction)?

Little

31

What does the sympathetic nervous system use to increase HR and force of contraction?

Norepinephrine

32

First way that norepinephrine increases HR

Decreasing / slowing outflow of K+ and depolarizing pacemaker cells in SA node

33

Second way that norepinephrine increases HR

Increases rate of Na+ leakage (speeds rate that pacemaker cells reach threshold)

34

How does norepinephrine increase strength in contraction of heart muscle?

Increasing Ca2+ currents in ventricular myocytes

35

Parasympathetic regulation of systemic vascular resistance

Acetylcholine decreases SVR
Vasodilation of systemic arterioles in organs that assist with resting and digesting
-Constriction in underutilized muscle is controlled locally

36

Effects of norepinephrine and epinephrine in sympathetic regulation of systemic vascular resistance depends on...

Target tissue

37

Acetylcholine receptors in sympathetic nervous system systemic vascular resistance regulation

In arterioles of skeletal, cardiac and pulmonary vascular smooth muscle causes vasodilation in these organs

38

Adrenergic receptors in sympathetic nervous system systemic vascular resistance regulation

Expressed just about everywhere else
-Alpha-adrenergic tend to be vaso-constrictive
-Beta adrenergic tend to be vasodilatory along with Ach

39

Net effect of sympathetic nervous system in systemic vascular resistance

Sympathetic division DECREASES SVR generally in areas of immediate need (muscles) but INCREASES SVR in areas that require lots of blood (liver)