The Cardio-Vascular System - Part 1 (week 8)

Question 1

state what the 3 components of the cardio-vascular system are

Answer 1

1. the heart
2. the blood vessels
3. the blood

Question 2

state what 3 things the cardio-vascular system is impacted by

Answer 2

1. endocrine system
2. nervous system
3. kidneys

Question 3

state what it is meant by the key term - systemic loop of the CV system

Answer 3

carries oxygenated blood from the heart to the major parts of the body and then back to the heart

Question 4

explain the systemic loop of the CV system (4 things)

Answer 4

1. blood leaves left ventricle via aorta
2. aorta branches to form systemic arteries
3. branches to form microcirculation
4. venules form the veins which ultimately form 2 vessels - superior and inferior vena cava

Question 5

state what it is meant by the key term - pulmonary loop of the CV system

Answer 5

carries deoxygenated blood from the heart to the lungs and then back to the heart

Question 6

explain the pulmonary loop of the CV system (4 things)

Answer 6

1. blood leaves right ventricle via pulmonary trunk
2. divides into pulmonary arteries which takes blood to both lungs
3. in the lungs: arterioles, capillaries, venules, veins
4. blood enters left atrium via pulmonary veins (depicted as one)

Question 7

state what it is meant by the key term - pressure

Answer 7

pressure refers to force exerted (mmHg)

Question 8

state what it is meant by the key term - flow

Answer 8

flow refers to the volume moved (mL/min)

Question 9

state what it is meant by the key term - resistance

Answer 9

resistance refers to how difficult it is for blood to flow between two points of any given pressure difference

Question 10

state 2 additional facts about resistance

Answer 10

1. resistance is the measure of the friction that impedes flow
2. increasing resistance decreases flow (if pressure stays the same)

Question 11

state what 3 things contribute to resistance

Answer 11

1. blood viscosity - effected by volume and number of erythrocytes
2. total blood vessel length - how much ‘tubing’ is needed
3. blood vessel diameter - relaxed vessels decrease resistance, vasoconstricted vessels increase resistance

Question 12

state the names of the 2 types of arteries

Answer 12

1. elastic/conduit arteries

2. muscular arteries

Question 13

state 4 facts about elastic/conduit arteries

Answer 13

1. located near heart and carry blood for circulation
2. large lumen vessels (low resistance) that contain more elastin than muscular arteries
3. allow them to be ‘pressure reservoirs’
4. expand and contract (recoil) as blood is ejected from the heart allowing blood flow to be continuous

Question 14

state 3 facts about muscular arteries

Answer 14

1. deliver blood to specific organs
2. have proportionally the most smooth muscle and are very active in vasoconstriction
3. can play a large role in the regulation of BP

Question 15

arteries act like elastic containers. state 2 factors that affect pressure in an elastic container (eg - a water balloon)

Answer 15

1. how much water you put in it

2. how easily the walls of the balloon can stretch

Question 16

state what it is meant by the key term - compliance

Answer 16

compliance is the term used to denote how easily a structure stretches

Question 17

what proportion of SV leaves arteries during systole, and what is the effect of this (3 points)

Answer 17

1. 1/3 SV remains in arteries during systole
2. rest of SV stays in arteries raising the blood pressure
3. after ventricular contraction, arteries recoil passively and blood continues to be driven into the arteries

Question 18

state what it is meant by the key term - systolic blood pressure

Answer 18

maximal arterial pressure reached during ventricular ejection

Question 19

state what it is meant by the key term - diastolic blood pressure

Answer 19

minimal arterial pressure reached just before ventricular ejection

Question 20

state what it is meant by the key term - pulse pressure

Answer 20

difference between systolic and diastolic blood pressure

Question 21

arterioles function is controlled by what 3 things

Answer 21

neural, hormonal and local chemicals

Question 22

state what the function of an arteriole is, and how do they do this (3 points)

Answer 22

1. arterioles function to control minute-to-minute blood flow in the capillary beds
2. if they contract, blood flow is directed away from the tissue
3. if they dilate, blood flow to the tissue increases

Question 23

state what it is meant by the key term - intrinsic tone

Answer 23

arterioles have a basal level of contraction called intrinsic tone and is smooth muscle regulated by local or extrinsic control

Question 24

state a fact about the smallest arterioles

Answer 24

the smallest arterioles, which directly lead into capillary beds, are usually just a single layer of smooth muscle which spirals around the endothelium

Question 25

state the 2 local control of resistance for arterioles

Answer 25

1. respond to local metabolic or local blood flow changes | 2. respond to injury

Question 26

state the 2 extrinsic control of resistance for arterioles

Answer 26

1. sympathetic nerves | 2. hormones

Question 27

state how responding to local metabolic or local blood flow changes effects resistance in arterioles (2 things)

Answer 27

1. blood flow increases to an organ due to increased metabolism 2. dec^ O2, inc^ CO2, inc^ K+, ine^ NO, inc^ H+, inc^ adenosine

Question 28

explain how responding to injury chances resistance in arterioles

Answer 28

local inflammation is characterised by increased blood flow

Question 29

explain how sympathetic nerves cause extrinsic control of resistance

Answer 29

there is always a sympathetic tone, this can be reduced resulting in vasodilation by withdrawing sympathetic activity

Question 30

explain how hormones cause extrinsic control of resistance (3 hormones)

Answer 30

1. epinephrine - vasodilator or vasoconstricts depending on the tissue 2. angiotensin 2 - constricts most arterioles 3. vasopressin - constricts most arterioles

Question 31

state the names of the 3 types of capillaries

Answer 31

1. continuous capillary 2. fenestrated capillary 3. sinusoidal capillary

Question 32

state what it is meant by the key term - continuous capillary

Answer 32

found in the skin, muscle, most common kind and have tight junctions

Question 33

state what it is meant by the key term - fenestrated capillary

Answer 33

more permeable than continuous capillaries. found at the intestine, hormone producing tissues, kidneys, etc...

Question 34

state what it is meant by the key term - sinusoidal capillaries

Answer 34

the only type of capillary with an incomplete basement membrane. found in the liver, bone marrow, and lymphoid tissue

Question 35

state the name for the process of capillary growth and development, and one additional fact about it

Answer 35

1. angiogenesis | 2. vascular epithelial cells release angiogenic factors (eg - vascular endothelial growth factor, VEGF)

Question 36

blood flow through the capillaries is dependent on what?

Answer 36

blood flow through the other vessels in the microcirculation

Question 37

in some tissues and organs, blood enters capillaries through (fill blank). the site at which a capillary exits from a (fill blank) is surrounded by an area of smooth muscle called a (fill blank)

Answer 37

1. meta arteriole 2. meta arteriole 3. pre-capillary sphincter

Question 38

the extremely low forward flow of blood through capillaries is beneficial. state why

Answer 38

it maximises the time available for substance exchange

Question 39

blood velocity is not dependent on distance from the heart. state what it is dependent on

Answer 39

the cross-sectional area of the vessel type

Question 40

in the systemic system, state the force driving blood in the veins

Answer 40

the pressure difference between the veins (15 mmHg) and the right atrium (0 mmHg)

Question 41

state the 2 major functions of veins

Answer 41

1. act as low pressure conduits returning blood to the heart 2. maintain peripheral venous pressure

Question 42

state the 2 factors which determine venous pressure

Answer 42

1. volume of blood in the veins | 2. compliance of vein walls

Question 43

what percentage of blood is in the veins

Answer 43

61 % of blood is in the veins and they have very compliant walls = low pressure

Question 44

state the 5 mechanisms of VR

Answer 44

1. skeletal muscle pump 2. smooth muscle 3. pocket valves 4. respiratory pump 5. gravity

Question 45

state what it is meant by the key term - bicuspid valve

Answer 45

the value separating the left atria from the left ventricle and consists of 2 fibrous flaps

Question 46

state what it is meant by the key term - tricuspid valve

Answer 46

the valve separating the right atria from the right ventricle and has 3 fibrous flaps

Question 47

state what it is meant by the key term - chordae tendineae

Answer 47

chordae tendineae function to fasten the AV valves to the papillary muscles

Question 48

state what it is meant by the key term - papillary muscles

Answer 48

papillary muscles do not open or close the AV valves, but limit their movement to prevent the back flow of blood

Question 49

state what it is meant by the key term - pericardium

Answer 49

the pericardium is the muscular sac enclosing the heart

Question 50

state what it is meant by the key term - epicardium

Answer 50

the epicardium fixes the inner layer of the pericardium to the heart (myocardium)

Question 51

state what it is meant by the key term - myocardium

Answer 51

the myocardium is the muscular wall of the heart which is formed by cardiac muscle cells