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Bio 20 > Circulation > Flashcards

Circulation Flashcards

1
Q

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

A

96,000km

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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

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3
Q

What is the blood volume of a human?

A

5L; entire volume is pumped every minute

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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
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5
Q

What do arteries do?

A

Carry blood away from the heart (Red)

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6
Q

What are arteries composed of?

A

Three distinct elastic layers give them thick walls

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7
Q

How do arteries work?

A

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

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8
Q

What are arterioles?

A

Smaller arteries (Red)

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9
Q

What is the middle layer of arterioles composed of?

A

Elastic fibres and smooth muscle

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10
Q

What are arterioles able to do?

A

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

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11
Q

What is vasoconstriction?

A

The narrowing of blood vessels, decreasing flow to the tissues

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12
Q

What is vasodilation?

A

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

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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)

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14
Q

What is the blood pressure of arteries?

A

High BP

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15
Q

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

A

The risk of rupturing and causing a bruise

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16
Q

What are venules?

A

Smaller blood vessels that form as capillaries merge (Blue)

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17
Q

What are venules lined with?

A

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

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18
Q

What are veins?

A

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

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19
Q

What do veins also serve as?

A

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

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20
Q

What is the blood pressure of veins?

A

Low BP

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21
Q

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

A

Uni-directional valves

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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

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23
Q

What is the path of systemic blood flow?

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

What is an aneurysm?

A

A bulge or weakening in the wall of a blood vessel

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25
What is atherosclerosis?
Degeneration of blood vessels caused by the accumulation of fat deposits (plaque) in the inner wall
26
What is bruising?
Rupture of capillary beds causing blood to leak into the extra-cellular space
27
What is varicose veins?
Damage to the one-way valves in veins causing blood to pool and the veins to bulge
28
What type of pumps does the heart consist of?
Two parallel pumps
29
What does the right pump do?
Connects to blood vessels that circulate blood to the lungs, for oxygenation, and back to the heart (Pulmonary circulatory system)
30
What does the left pump do?
Connects blood vessels to the body and circulates blood to the body tissues (Systemic circulatory system)
31
What maintains one way blood flow?
Uni-directional valves in the heart and in the blood vessels
32
What is the name of the third blood flow?
Coronary blood flow
33
What is the pericardium?
A lubricated sac that the heart sits in
34
What is an atria?
Top chamber of the heart that contracts to push blood into the bottom ventricular chamber
35
What is the aorta?
Largest artery in the body; carries oxygenated blood to the body tissues
36
What are atrioventricular valves (AV valves)?
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
What side is the tricuspid valve on?
Right side
38
What side is the bicuspid valve on?
Left side
39
What anchor the valves to ensure one way flow?
Chordae tenidea
40
What are coronary arteries?
Branch from the aorta and supply the heart muscle with oxygenated blood
41
What are pulmonary arteries and veins?
Carry deoxygenated blood to (artery) and oxygenated blood from (vein) the lungs; opposite of what it should be
42
What is a semi-lunar valve (pulmonary valve)?
Prevents blood from flowing backwards from the pulmonary artery/vein, back to the ventricles
43
What is the septum?
Muscular wall that separates the left and right sides of the heart
44
What is the vena cava?
Largest vein; carries blood from the upper body (superior) or the lower body (inferior) back to the heart
45
What are ventricles?
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
What is the order of blood flow through the heart?
- 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
Where are AV valves found?
Between the right atrium and right ventricle, and between | the left atrium and left ventricle
48
Where are semi-lunar valves found?
Between the right ventricle and the pulmonary artery, and between the left ventricle and aorta
49
What type of muscle is the heart?
Myogenic muscle
50
What is unique about myogenic muscles?
It’s able to contract without external nerve stimulation
51
What part of the nervous system controls heart beat?
Sympathetic (stimulating) and parasympathetic (relaxing) branches
52
What sets the heart's rate and where is it located?
A small mass of tissue called the sinoatrial node (SA node); found in the right atrium
53
What is the sinoatrial node known as?
The pacemaker
54
Where do contraction radiate to from the SA node?
Travel to the atrioventricular node (AV node) through the bundle of His
55
What do the contractions pass nerve pulses along?
Two large nerve fibres called purkinje fibres to the septum and the ventricles
56
Where does the resulting wave of contraction move?
From the atria to the ventricles, up from bottom of the ventricles, forcing blood out the atria/ pulmonary arteries
57
What is normal heart rate?
80 BPM
58
What is bradycardia?
< 50 BPM
59
What is tachycardia?
> 100 BPM
60
What is systole?
Contraction of the heart muscle
61
What is diastole?
Relaxation of the heart muscle?
62
What is an ECG?
Electrocardiogram; shows the electrical conductivity of the heart and is used to identify and diagnose heart conditions
63
What sound does the heart make?
Lubb-dubb
64
What is a heart murmur?
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
What sound does a heart murmur make?
Lubb-dubb-squish
66
What creates the lubb sound?
AV closes; atria contracts, ventricle relaxes
67
What creates the dumb sound?
Semi lunar closes; atria relaxes, ventricle contracts
68
What 3 things affect blood pressure?
1. Cardiac output 2. Stroke volume 3. Heart rate
69
What is cardiac output?
The amount of blood that flows out of the heart each minute; can be influenced by stroke volume and heart rate
70
What is stroke volume?
The volume of blood pumped with each beat of the heart; on average the stroke volume is about 70 mL/beat
71
What is heart rate?
The number of beats per minute of the heart
72
What is hypertension?
Blood pressure is too high
73
What is hypotension?
Blood pressure is too low; chronic
74
What is blood pressure?
The force of the blood on the walls of your arteries
75
What influences BP?
Age, level of fitness, level of hydration, and level of stress
76
What is blood pressure measured by?
Baroreceptors (stretch receptors) in your aortic arch or the carotid artery
77
What are the two major factors BP depends on?
1. Cardiac output | 2. Arteriolar resistance
78
Why does cardiac output have an effect on BP?
Higher blood volume = Higher BP; may be influenced by fluid retention. Higher heart rate = Higher BP
79
Why does arteriolar resistance have an effect on BP?
Blood vessel size, The diameter of the arteries will determine the pressure within them. Vasoconstriction will cause greater BP. Vasodilation decreases BP
80
What do capillaries do?
Carry oxygen, glucose, and amino acids to cells, as well as remove wastes such as CO2
81
What is extracellular fluid (ECF)?
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
What two forces cause the exchange of nutrients, wastes, and gases?
1. Fluid pressure/Filtration | 2. Osmotic Pressure/Absorption
83
What is fluid pressure/ filtration?
BP created by the heart and and blood volume. Filter oxygen and nutrients out of the capillaries at the arteriole end
84
What is osmotic pressure/ absorption?
Pressure created by water pushed CO2 and waste back into the capillaries at the venuole end
85
What is the arteriole end of capillaries?
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
What is the venue end of capillaries?
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

Bio 20 (13 decks)

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