Lecture 8 - Cardiovascular System Flashcards

1
Q

What is the function of the Cardiovascular system impacted by

A

Endocrine System
Nervous system
Kidneys

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2
Q

What are the 2 loops in the cardiovascular system

A

Systemic
Pulmonary

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3
Q

What does the systemic loop do

A

carries blood to from the heart to themajor parts of the body and back to the heart

Blood leaves the left ventricle via the aorta
Branches to form systemic arteries

Branch to form the microcirculation: Arterioles, capillaries, venules

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4
Q

What do the venules that form veins ultimately form

A

Inferior Vena Cava - Collects blood from below heart
Superior Vena Cava - Collects blood from above the heart

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5
Q

What is the job of the Pulmonary loop

A

carries oxygen-poor blood to the lungs and
back to the heart.
Blood leaves right ventricle: pulmonary trunk
Dividing into pulmonary arteries – take blood to both lung

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6
Q

What are the 5 types of blood vessels

A

Arteries
Arterioles
Capillaries
Venules
Veins

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7
Q

What is the exception to the rule “arteries carry oxygenated blood and veins carry deoxygenated blood”

A

the pulmonary arteries
- carry deoxygenated blood to the lungs
- here they collect oxygenated blood and
- the pulmonary veins carry oxygenated blood to the heart

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8
Q

What is the pressure in a blood vessel

A

Pressure is the force exerted and we measure this in mm Hg

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9
Q

What is flow in blood vessels

A

Flow is the volume moved and it is measured in mL/min

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10
Q

What is the resistance in a blood vessel

A

Resistance is how difficult it is for blood to flow between two points at any given
pressure difference

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11
Q

What are 3 things that contribute to the resistance in blood vessels

A

Blood viscosity
Total Blood Vessel length
Blood Vessel diameter

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12
Q

Where are elastic/conduit arteries located

A

These vessels are near the heart and carry blood for
circulation eg. the aorta

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13
Q

What are some features elastic/conduit arteries

A

Large lumen vessels (low resistance) that contain more elastin
than the muscular arteries.
Allows them to be “pressure reservoirs”
‒ expand and contract (recoil) as blood is ejected by the
heart. This allows blood flow to be continuous.

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14
Q

What are muscular arteries and their key traits

A

These arteries deliver blood to specific organs (mesenteric artery, renal artery etc.).

They have proportionally the most smooth muscle and are very active in vasoconstriction.

These arteries can play a large role in the regulation of blood pressure

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15
Q

What is compliance

A

how easily a structure stretches

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16
Q

What are some factors affecting pressure in an elastic container

A

How much water you put in it
How easily the walls of the balloon (eg.) can stretch

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17
Q

What is systolic blood pressure

A

Maximal arterial pressure reached during peak ventricular ejection

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18
Q

What is diastolic blood pressure

A

Minimal arterial pressure reached just before ventricular ejection

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19
Q

What is pulse pressure

A

Difference between systolic and diastolic pressure

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20
Q

What is intrinsic tone

A

Arterioles have basal level of contraction

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21
Q

How is smooth muscle regulated

A

Autonomically by local or extrinsic control

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22
Q

How does the dilation/contraction of arterioles affect minute-to-minute blood flow

A

If they contract, blood flow is diverted away from their tissues

If they Dilate, then blood flow to the tissue increases

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23
Q

What is an example of local control of resistance

A

Response to local metabolic or local blood flow changes
eg.Blood flow increases to an organ due to an increase in metabolism (eg. exercising skeletal muscle)

Response to injury - local inflammation Is characterised by increased blood flow

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24
Q

What are some examples of extrinsic control of resistance

A

Hormones
Sympathetic nerves

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25
Q

What does Epinephrine do

A

vasodilates or constricts
depending on the tissue

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26
Q

What does angiotensin II do

A

Constricts most arterioles

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27
Q

What does Vasopressin do

A

Constricts most arterioles

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28
Q

What is the affect of symapthetic nerves on arterioles

A

Always some sympathetic tone, this can be
reduced resulting in vasodilation, by
withdrawing sympathetic activity

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29
Q

What are the 3 types of capillary

A

Continuous capillary: found in skin, muscle, most
common kind have tight junctions.

Fenestrated capillary: more permeable —
intestines, hormone-producing tissues, kidneys,
etc.

Sinusoidal capillary: only one with an incomplete
basement membrane; these are found in the liver,
bone marrow and lymphoid tissues.

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30
Q

What is angiogenesis

A

Capillaries develop and grow (through muscle adaptation or tumours)

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31
Q

What does VEGF do

A

Increase endothelial growth - released by vascular endothelial cells

32
Q

What is a precapillary sphincter

A

The site at which a capillary
exits from a metarteriole is
surrounded by a ring of
smooth muscle,

33
Q

In some tissues, what does blood enter through to reach the capillaries

A

metarterioles

34
Q

How does the slow forward movement of blood through the capillaries help the human body

A

maximises the
time for substance exchange across the
capillary wall

35
Q

What are the major functions of veins

A

Act as low pressure conduits returning blood to the heart

Peripheral venous pressure

36
Q

What are the factors determining venous pressure

A

Amount of blood in veins
Compliance of walls

37
Q

What is the pressure in the veins

A

(10-15mmHG)
(Right atrium is 0 - creates pressure differential drawing blood up)

38
Q

What is the pericardium

A

Muscular sack enclosing heart

39
Q

What is the Epicardium

A

Fixes inner layer of pericardium to the heart

40
Q

What is the myocardium

A

Muscular wall of the heart formed from cardiac muscle cell (hypertrophic cardiomyopathy)

41
Q

What is the atrioventricular system

A

Muscular wall separating the ventricles

42
Q

What do the Atrioventricular valves do

A

Permit flow from atrium to ventricle but not backward

43
Q

What is hypertrophic cardiomyopathy

A

Disease in which the heart muscle becomes thickened

44
Q

Where is the pulmonary semi lunar valve

A

Blood from right ventricle to pulmonary trunk

45
Q

Where is the aortic semi-lunar valve

A

Blood from left ventricle to aorta

46
Q

What are chordae tendinae

A

fasten
AV valves to the papillary
muscles

47
Q

What are Papillary muscles

A

Do not
open or close the AV
valves, but limit
movement to prevent
backward flow of blood. (pressure changes do)

48
Q

Why does cardiac muscle have large mitochondria

A

produce the energy
needed and prevent the heart
from fatiguing.

49
Q

What do cardiac muscle cells do

A

Branching cells with gap junctions that are critical
to the hearts ability to be
electrically stimulated.

50
Q

What are node cells (cardiac muscle)

A

have the ability
to stimulate their own action
potentials. This is called
automaticity or auto-
rhythmicity (“pacemarker
potential”, constant rhythm of
electrical activity)

51
Q

How does the sympathetic nervous system innervate the heart

A

innervates the entire heart muscle and node cells
and release norepinephrine (increases heart rate)

52
Q

How does the parasympathetic nervous system innervate the heart

A

innervates the node cells and release
primarily acetylcholine (slows down heart rate)

53
Q

What is the depolarisation ordering

A

Sinoatrial node - Atrial muscle cell - atrioventricular node - Bundle of His - left and Right bundle branches - L and R Purkinje fibres - Ventricular muscle cells

54
Q

How does the wave of depolarisation from the SA node travel

A

Through the internodal pathway (via gap junctions) to the atrioventricular node

Signal is delayed 0.1s to allow atria to contract and totally fill ventricles

55
Q

What is the QRS complex a result of

A

The ventricular depolarisation and precedes ventricular contraction

56
Q

What is the P wave (ECG)

A

Result of depolarisation wave from the SA node to the AV node. Atria contract
0.1 second after P wave starts.

57
Q

What is a T wave (ECG)

A

caused by ventricular depolarisation

58
Q

What is cardiac output

A

amount of blood pumped out of each ventricle in one minute

59
Q

What is stroke volume

A

Stroke volume is the difference between end diastolic volume and the end systolic volume

60
Q

How do you calculate Cardiac output

A

CO = HR (bpm) x Stroke Volume

61
Q

How do you calculate Stroke volume

A

SV = End Diastolic Volume - End systolic volume

62
Q

What is the Frank Starling mechanism

A

the ventricle contracts more forcefully during systole when it has been filled to a greater degree during diastole

63
Q

What is contractility

A

The strength of a contraction at any given end-diastolic volume

(increased by Norepinephrine, adrenaline or plasma epinephrine)

64
Q

How do you calculate mean arterial pressure

A

MAP = Diastolic pressure + 1/3 (Systolic pressure − diastolic pressure)

65
Q

What is mean arterial pressure dependant on

A

Mean arterial pressure = Cardiac Output × Total Peripheral Resistance

66
Q

What do arterial baroreceptors respond to

A

Changes in arterial pressure - degree of stretching is directly proportional to blood pressure

67
Q

what are baroreceptors controlled by

A

Medulla oblongata

68
Q

What does increased firing of baroreceptors lead to

A

LOWER sympathetic outflow to heart, arterioles,
veins and an HIGHER parasympathetic outflow to heart

69
Q

How do you treat hypertension

A

Diuretics
beta blockers
Calcium channel blockers
ACE inhibitors

70
Q

What do the intra-renal baroreceptors do

A

detect changes in stretching with due
to lower blood volume which stimulates an increase
in the production of renin

71
Q

Where are Angiotensin-converting enzymes (ACEs) found

A

Endothelial cells

72
Q

What is aldosterone

A

slow-acting steroid hormone that
stimulates sodium reabsorption by kidney tubules

73
Q

What is vasopressin (anti-diuretic)

A

rapid-
acting peptide produced by the pituitary gland
which stimulates water reabsorption

74
Q

What does Atrial Natriuretic Peptide (ANP) do

A
  1. Inhibits sodium reabsorption by kidney tubular cells
  2. Acts on renal blood vessels to increase filtration rate
    causing sodium excretion
  3. Inhibits the action of aldosterone
75
Q

Independent learning task - 367-370

A