Heart Physiology 2 Flashcards Preview

HSF - Viscera > Heart Physiology 2 > Flashcards

Flashcards in Heart Physiology 2 Deck (45):
1

What are the functions of the circulatory system?
1)
2)
3)
4)
5)

1) Distribution of dissolved gasses
2) Waste removal
3) Chemical signalling
4) Mediate inflammatory, immune responses
5) Conserve or release heat from skin surface

2

What is a portal system?

Two capillary beds in series
EG: In kidneys, stomach, liver

3

Which blood vessels have elastic tissue?

Arteries, veins

4

Which blood vessels have smooth muscle?

Arteries, arterioles, veins

5

Where is the highest and lowest mean systemic blood pressure?

Aorta (highest)
Vena cavae (lowest)

6

Where is blood flow slowest?

Capillaries

7

What is the Windkessel effect?

Reduction in arterial pressure changes during systole and diastole (heartbeat)

Caused by elastin in walls of arteries, walls distend in systole, recoil in diastole

8

Where is the Windkessel effect relevant?

In arteries

9

How to proteins move across the membranes of capillaries?

Transcytosis

10

Which tissues make up the walls of arteries?

Endothelium
Elastic tissue
Smooth muscle
Fibrous tissue

11

Which tissues make up the walls of veins?

Endothelium
Elastic tissue
Smooth muscle
Fibrous tissue

12

Which tissues make up the walls of arterioles?

Endothelium
Smooth muscle

13

Which tissues make up the walls of capillaries?

Endothelium

14

Which tissues make up the walls of venules?

Endothelium
Fibrous tissue

15

Mean arterial diameter

4mm

16

Mean venous diameter

5mm

17

Mean arterial wall thickness

1mm

18

Mean venous wall thickness

0.5mm

19

Proportion of blood stored in systemic veins

64%

20

Proportion of blood stored in arteries

13%

21

How far are most cells from a capillary?

0.1mm

22

What is bulk flow?

Overall movement of fluid between blood and tissues
Difference between hydrostatic pressure and colloid osmotic pressure

23

What is absorption?

Movement of fluid from interstitium into capillaries

24

What is filtration?

Fluid movement out of capillaries into interstitium

25

What is oedema?

Interstitial fluid accumulation

26

Difference in solute concentrations between blood and interstitial fluid

Electrolyte balance the same

Proteins in blood, too large to get into interstitial fluid

27

What are the pressures influencing bulk flow?

Osmotic pressure (pi) - Movement into capillary

Hydrostatic pressure (P) - Movement out of capillary

28

What is colloid (or oncotic) osmotic pressure?

Osmotic pressure caused by proteins in the blood that can't penetrate the endothelium of capillaries

29

What is the plasma oncotic pressure vs the interstitial fluid oncotic pressure?

25mmHg (plasma)
0mmHg (interstitial)

30

What is hydrostatic pressure?

The pressure exerted by the blood on the blood vessel walls.

Decreases with length

31

What is hydrostatic pressure in capillaries at the arteriolar end?

32mmHg

32

What is the hydrostatic pressure in capillaries at the venous end?

15mmHg

33

What is the hydrostatic pressure in the interstitial fluid?

0mmHg

34

What is the bulk flow at the arterial end of a capillary?

~7mmHg

35

What is the bulk flow at the venous end of a capillary?

~-10mmHg

36

Which pressure favours filtration?

Hydrostatic pressure

37

Which pressure favours absorption?

Colloid osmotic pressure

38

Is colloid osmotic pressure constant, or does it change with capillary length?

Constant

39

Is hydrostatic pressure constant, or does it change with capillary length?

Decreases with capillary length

40

What is the net fluid movement of fluid per day?

3L out of capillaries per day

41

Where does the excess fluid filtrated into the interstitial fluid go?

Into the lymphatic system

42

Where do the largest lymph vessels empty?

Into the venous system

Where the left/right subclavian veins join internal jugular veins

43

What plays a large role in pumping lymph?

Skeletal muscle pump

44

Roles of lymphatic system
1)
2)
3)

1) Return fluid and proteins filtered back into circulation
2) Pick up fat absorbed in small intestine, transfer to circulatory system
3) Immune system

45

What factors pump lymph?
1)
2)
3)

1) Smooth muscle contractions in larger lymph nodes
2) Skeletal muscle contraction
3) One-way valves