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Flashcards in Circulation Deck (86)
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1
Q

How long (blood vessels) is the human circulatory system?

A

96,000km

2
Q

Who proved that blood was of limited volume and that it is recirculated in the circulatory system and is pumped by the heart in one direction?

A

William Harvey

3
Q

What is the blood volume of a human?

A

5L; entire volume is pumped every minute

4
Q

What are the five things the circulatory system does?

A
  1. Carries oxygen and nutrients to cells
  2. Carries CO2 and waste away from cells
  3. Carries hormones to target organs
  4. Distributes heat throughout the body
  5. Helps defence of invading micro-organisms
5
Q

What do arteries do?

A

Carry blood away from the heart (Red)

6
Q

What are arteries composed of?

A

Three distinct elastic layers give them thick walls

7
Q

How do arteries work?

A

Each time the heart pumps the arteries stretch to accommodate the rush of blood

8
Q

What are arterioles?

A

Smaller arteries (Red)

9
Q

What is the middle layer of arterioles composed of?

A

Elastic fibres and smooth muscle

10
Q

What are arterioles able to do?

A

Contract and relax, controlling the flow of blood to different parts of the body

11
Q

What is vasoconstriction?

A

The narrowing of blood vessels, decreasing flow to the tissues

12
Q

What is vasodilation?

A

The widening/relaxation of blood vessels, increasing flow to the tissues

13
Q

What are capillaries?

A

Tiny blood vessels composed of a single layer of cells; this is the site of fluid and gas exchange between cells and the body tissues (Blue and Red/Purple)

14
Q

What is the blood pressure of arteries?

A

High BP

15
Q

Because pressure is high in the capillaries, what is increased?

A

The risk of rupturing and causing a bruise

16
Q

What are venules?

A

Smaller blood vessels that form as capillaries merge (Blue)

17
Q

What are venules lined with?

A

Smooth muscle; ensures that blood continues to flow back towards the heart

18
Q

What are veins?

A

Larger blood vessels that result as venules merge, take blood back to the heart (Blue)

19
Q

What do veins also serve as?

A

Blood reservoirs, hold up to 65% of the total blood volume

20
Q

What is the blood pressure of veins?

A

Low BP

21
Q

Because veins have low BP, what do they have to ensure the one way flow of blood?

A

Uni-directional valves

22
Q

What else helps aid venous flow?

A

Skeletal muscles; venous pressure increases when skeletal muscles contract and push on the vein, forcing blood upwards

23
Q

What is the path of systemic blood flow?

A
  1. Artery
  2. Arteriole
  3. Capillary
  4. Venule
  5. Vein
24
Q

What is an aneurysm?

A

A bulge or weakening in the wall of a blood vessel

25
Q

What is atherosclerosis?

A

Degeneration of blood vessels caused by the accumulation of fat deposits (plaque) in the inner wall

26
Q

What is bruising?

A

Rupture of capillary beds causing blood to leak into the extra-cellular space

27
Q

What is varicose veins?

A

Damage to the one-way valves in veins causing blood to pool and the veins to bulge

28
Q

What type of pumps does the heart consist of?

A

Two parallel pumps

29
Q

What does the right pump do?

A

Connects to blood vessels that circulate blood to the lungs, for oxygenation, and back to the heart (Pulmonary circulatory system)

30
Q

What does the left pump do?

A

Connects blood vessels to the body and circulates blood to the body tissues (Systemic circulatory system)

31
Q

What maintains one way blood flow?

A

Uni-directional valves in the heart and in the blood vessels

32
Q

What is the name of the third blood flow?

A

Coronary blood flow

33
Q

What is the pericardium?

A

A lubricated sac that the heart sits in

34
Q

What is an atria?

A

Top chamber of the heart that contracts to push blood into the bottom ventricular chamber

35
Q

What is the aorta?

A

Largest artery in the body; carries oxygenated blood to the body tissues

36
Q

What are atrioventricular valves (AV valves)?

A

The tricuspid and bicuspid valves separate the artery from the ventricles on the right and left sides respectively. These valves ensure a one way flow of blood within the heart.

37
Q

What side is the tricuspid valve on?

A

Right side

38
Q

What side is the bicuspid valve on?

A

Left side

39
Q

What anchor the valves to ensure one way flow?

A

Chordae tenidea

40
Q

What are coronary arteries?

A

Branch from the aorta and supply the heart muscle with oxygenated blood

41
Q

What are pulmonary arteries and veins?

A

Carry deoxygenated blood to (artery) and oxygenated blood from (vein) the lungs; opposite of what it should be

42
Q

What is a semi-lunar valve (pulmonary valve)?

A

Prevents blood from flowing backwards from the pulmonary artery/vein, back to the ventricles

43
Q

What is the septum?

A

Muscular wall that separates the left and right sides of the heart

44
Q

What is the vena cava?

A

Largest vein; carries blood from the upper body (superior) or the lower body (inferior) back to the heart

45
Q

What are ventricles?

A

Large muscular chambers that pump blood to the lungs (right), or to the body (left). The wall of the left ventricle is thicker because it pumps blood further

46
Q

What is the order of blood flow through the heart?

A
  • Body cells (deoxygenated)
    1. Inferior/superior Vena Cava
    2. Right atrium
    3. Right ventricle
    4. Pulmonary artery (to lungs)
    5. Pulmonary vein (from lungs)
    6. Left atrium
    7. Left ventricle
    8. Aorta
47
Q

Where are AV valves found?

A

Between the right atrium and right ventricle, and between

the left atrium and left ventricle

48
Q

Where are semi-lunar valves found?

A

Between the right ventricle and the pulmonary artery, and between the left ventricle and aorta

49
Q

What type of muscle is the heart?

A

Myogenic muscle

50
Q

What is unique about myogenic muscles?

A

It’s able to contract without external nerve stimulation

51
Q

What part of the nervous system controls heart beat?

A

Sympathetic (stimulating) and parasympathetic (relaxing) branches

52
Q

What sets the heart’s rate and where is it located?

A

A small mass of tissue called the sinoatrial node (SA node); found in the right atrium

53
Q

What is the sinoatrial node known as?

A

The pacemaker

54
Q

Where do contraction radiate to from the SA node?

A

Travel to the atrioventricular node (AV node) through the bundle of His

55
Q

What do the contractions pass nerve pulses along?

A

Two large nerve fibres called purkinje fibres to the septum and the ventricles

56
Q

Where does the resulting wave of contraction move?

A

From the atria to the ventricles, up from bottom of the ventricles, forcing blood out the atria/ pulmonary arteries

57
Q

What is normal heart rate?

A

80 BPM

58
Q

What is bradycardia?

A

< 50 BPM

59
Q

What is tachycardia?

A

> 100 BPM

60
Q

What is systole?

A

Contraction of the heart muscle

61
Q

What is diastole?

A

Relaxation of the heart muscle?

62
Q

What is an ECG?

A

Electrocardiogram; shows the electrical conductivity of the heart and is used to identify and diagnose heart conditions

63
Q

What sound does the heart make?

A

Lubb-dubb

64
Q

What is a heart murmur?

A

Occurs when the heart valves are faulty and don’t close completely. Blood rushes from the ventricle back into the atrium creating a squishing sound that is heard as a murmur

65
Q

What sound does a heart murmur make?

A

Lubb-dubb-squish

66
Q

What creates the lubb sound?

A

AV closes; atria contracts, ventricle relaxes

67
Q

What creates the dumb sound?

A

Semi lunar closes; atria relaxes, ventricle contracts

68
Q

What 3 things affect blood pressure?

A
  1. Cardiac output
  2. Stroke volume
  3. Heart rate
69
Q

What is cardiac output?

A

The amount of blood that flows out of the heart each minute; can be influenced by stroke volume and heart rate

70
Q

What is stroke volume?

A

The volume of blood pumped with each beat of the heart; on average the stroke volume is about 70 mL/beat

71
Q

What is heart rate?

A

The number of beats per minute of the heart

72
Q

What is hypertension?

A

Blood pressure is too high

73
Q

What is hypotension?

A

Blood pressure is too low; chronic

74
Q

What is blood pressure?

A

The force of the blood on the walls of your arteries

75
Q

What influences BP?

A

Age, level of fitness, level of hydration, and level of stress

76
Q

What is blood pressure measured by?

A

Baroreceptors (stretch receptors) in your aortic arch or the carotid artery

77
Q

What are the two major factors BP depends on?

A
  1. Cardiac output

2. Arteriolar resistance

78
Q

Why does cardiac output have an effect on BP?

A

Higher blood volume = Higher BP; may be influenced by fluid retention. Higher heart rate = Higher BP

79
Q

Why does arteriolar resistance have an effect on BP?

A

Blood vessel size, The diameter of the arteries will determine the pressure within them. Vasoconstriction will cause greater BP. Vasodilation decreases BP

80
Q

What do capillaries do?

A

Carry oxygen, glucose, and amino acids to cells, as well as remove wastes such as CO2

81
Q

What is extracellular fluid (ECF)?

A

Fluid that occupies the spaces between cells. The fluid will then come into contact with both cells and the capillaries to facilitate the transport of oxygen, glucose, amino acids, and waste

82
Q

What two forces cause the exchange of nutrients, wastes, and gases?

A
  1. Fluid pressure/Filtration

2. Osmotic Pressure/Absorption

83
Q

What is fluid pressure/ filtration?

A

BP created by the heart and and blood volume. Filter oxygen and nutrients out of the capillaries at the arteriole end

84
Q

What is osmotic pressure/ absorption?

A

Pressure created by water pushed CO2 and waste back into the capillaries at the venuole end

85
Q

What is the arteriole end of capillaries?

A

A high BP on the inside of the vessel vs. a low osmotic pressure on the outside of the vessel allows for oxygen and nutrients to be squished outwards and into the
ECF to be picked up by cells

86
Q

What is the venue end of capillaries?

A

A low BP on the inside of the vessel vs. a high osmotic pressure on the outside of the vessel allows for CO2 and waste to be squished inwards and into the blood vessel to be delivered back to the heart