OC3 - cardiovascular system

Question 1

what are the three layers of the heart wall?

Answer 1

epicardium
myocardium - cardiac muscle
endocardium

Question 2

what is the pericardium?

Answer 2

the heart is surrounded by the pericardium
a loose fitting membrane which holds the heart in place
a double-layered sac covering the heart
the outer layer anchors the heart in the chest
the inner layer is attached to the heart wall
lubricating fluid in pericardial space reduces friction.

Question 3

what is the structure of the heart?

Answer 3

diagram…
4 chambers
valves

Question 4

what are the four chambers of the heart?

Answer 4

left and right atria - separated by septum
left and right ventricle - separated by intraventricular septum

Question 5

what is the function of valves in the heart?

Answer 5

prevent back flow of blood

Question 6

what is the composition of the valves in the heart?

Answer 6

composed of connective tissue - tendon like cords
held in place by muscles

Question 7

what are the types of valves in the heart?

Answer 7

semilunar
atrioventricular

Question 8

what are the semilunar valves?

Answer 8

pulmonary valve
aortic valve
the tendinous cords of the semilunar valves prevent the cusps of the valve opening to prevent backwards blood flow from the arteries to the ventricles.

Question 9

what are the atrioventricular valves?

Answer 9

tricuspid valve - right atrium to right ventricle
bicuspid (mitral) valve - left atrium to left ventricle
the tendinous cords of the AV valves prevent the cusps of the valve opening to allow flow of blood from the ventricles to the atria.

Question 10

what is the circulation route?

Answer 10

vena cava - right atrium - right ventricle - pulmonary artery - lungs - pulmonary vein - left atrium - left ventricle - aorta

Question 11

what is the cardiac cycle?

Answer 11

the heart beat is a cycle of cardiac muscle contraction and relaxation.

Question 12

what is cardiac muscle contraction called?

Answer 12

systole

Question 13

what is cardiac muscle relaxation called?

Answer 13

diastole

Question 14

what is atrial systole?

Answer 14

the atria simultaneously contract and send blood to the ventricles

Question 15

what is ventricular systole?

Answer 15

the ventricles contract forcing semilunar valves to open and send blood into pulmonary artery (R) and aorta (L)

Question 16

what is complete cardiac diastole?

Answer 16

occurs after systole, the chambers of the heart relax, allowing the blood to return to atria

Question 17

what are the circulation types?

Answer 17

pulmonary circulation
systemic circulation

Question 18

what is pulmonary circulation?

Answer 18

the loop of blood from the heart to the lungs
blood is carried from the heart to the lungs by the pulmonary artery and is returned to the heart by the pulmonary vein
blood gets oxygenated

Question 19

what is systemic circulation?

Answer 19

the loop of blood from the heart to the body
blood is carried from the heart in the aorta, and travels around numerous vessels to be returned to the heart in the vena cava
to provide the body with oxygenated blood.

Question 20

what are the components of blood?

Answer 20

plasma (55%)
cells (45%)

Question 21

what is the composition of blood?

Answer 21

plasma - water, proteins, nutrients, hormones
buffy coat - white blood cells, platelets
hematocrit - red blood cells

Question 22

what are the components of plasma?

Answer 22

water - 91.5%
solutes - 1.5%
proteins - 7%

Question 23

what are the solutes found in plasma?

Answer 23

electrolytes - Na+, K+
nutrients - amino acids, glucose, fatty acids, glycerole
gases - O2, CO2, N2

Question 24

what are the protein found in plasma?

Answer 24

albumins
globulins
fibrinogen

Question 25

what are the cell types in blood?

Answer 25

erythrocytes - red blood cells leucocytes - white blood cells thrombocytes - platelets

Question 26

what is the function of blood?

Answer 26

transportation of oxygen nutrients and hormones regulation of body temperature protection against infections by white blood cells

Question 27

what is haemoglobin?

Answer 27

a protein molecule that can bind four oxygen molecules per haemoglobin molecule contains an iron-containing haem group that gives red blood cells their colour.

Question 28

erythrocytes structure

Answer 28

biconcave disc gives a larger surface area to volume ration efficient for gas exchange flexible - can fit through capillaries carry haemoglobin which carries oxygen (x4) have no organelles - increases space in the cytoplasm for haemoglobin

Question 29

blood groups

Answer 29

red blood cells have glycolipids/glycoproteins on their surface which determines blood groups

Question 30

what are the types of lymphocytes?

Answer 30

T cells - thymus B cells - lymph nodes

Question 31

what are thrombocytes (platelets)?

Answer 31

formed from small pieces of cytoplasm shed from large cells called megakaryocytes involved in blood vessel repair and the clotting mechanism.

Question 32

what is the clotting cascade?

Answer 32

diagram platelets release thromboplastin when injured, this converts prothrombin to thrombin which eventually converts soluble fibrinogen to insoluble fibrin forming a sticky web to trap other blood cells - to form a clot - haemostasis.

Question 33

what is cardiac output?

Answer 33

the volume of blood pumped out of each ventricle per minute (l/min, or ml/min) determined by the heart rate and the stroke volume influenced by blood pressure and resistance CO = HR x SV CO = MAP/TPR

Question 34

what is the relationship between cardiac output and blood pressure

Answer 34

⬆CO = ⬆BP (during exercise)

Question 35

what is stroke volume?

Answer 35

the volume of blood ejected by each ventricle per beat

Question 36

what is mean arterial blood pressure (MAP)?

Answer 36

average blood pressure within the body the pressure exerted on the wall of a blood vessel

Question 37

what is total peripheral resistance (TPR)?

Answer 37

the force of friction as blood moves along the vessels

Question 38

what is blood pressure?

Answer 38

the pressure exerted on the wall of a blood vessel highest in the aorta, lowest in the vena cava

Question 39

what factors increase blood pressure?

Answer 39

increase in cardiac output increase in blood volume increase in peripheral resistance

Question 40

what is peripheral resistance?

Answer 40

the impedance of blood flow

Question 41

what factors influence peripheral resistance?

Answer 41

blood viscosity - ⬆viscosity = ⬆resistance = ⬆BP blood vessel length - ⬆length = ⬆ resistance blood vessel radius - ⬇radius = ⬆ resistance vasodilation ⬇resistance = ⬆blood flow vasoconstriction ⬆ resistance = ⬇blood flow

Question 42

what is the influence of an increase in fitness?

Answer 42

same cardiac output with a lower heart rate increased stroke volume - myocardial contractions are more forceful and efficient due to increased muscular tome of the myocardium lower resting heart rate

Question 43

what are the vessels in the cardiovascular system?

Answer 43

arteries veins capillaries arterioles venules

Question 44

what are arteries?

Answer 44

carry blood at high pressure away from the heart they are elastic change diameter by muscle contraction - vasodilation and vasoconstriction maintain blood pressure have thick walls as there is a high blood pressure exerted on them have a large internal diameter inner wall is very smooth to limit plaque build-up

Question 45

what are veins?

Answer 45

carry blood at low pressure back to the heart against the force of gravity contain valves to prevent the back flow of blood this is aided by the action of skeletal muscle.

Question 46

what are capillaries?

Answer 46

have very thin walls - one cell thick near every tissue cell involved in gas and nutrient exchange - drop off oxygen delivered from heart by arteries, and, pick up CO2 and send it to the hear via veins connect arteries and veinsw

Question 47

what are arterioles?

Answer 47

small arteries undergo vasoconstriction/dilation so regulate blood flow into the capillaries affect blood pressure

Question 48

what are venules?

Answer 48

very small veins

Question 49

hepatic portal circulation

Answer 49

diagram

Question 50

what is the conduction system of the heart?

Answer 50

Sinoatrial node undergoes spontaneous electrical activity generating action potentials which spread through the myocardial cells of the right and left atria causing a slight (?) contraction of the atria. The action potential then reaches the atrioventricular node causing a complete (?) contraction of the atria, pushing blood from the atria to the ventricles through the atrioventricular valves. The signal then passes down the bundle of His which divides into right and left bundles before passing the signal to the purkinje fibres where it is conducted through the ventricles causing contraction of the ventricles pushing blood from the ventricles to the pulmonary artery (R) and aorta (L) through the semilunar valves.

Question 51

what is the autonomic control of heart rate?

Answer 51

medulla of the brain contains 2 groups of neurones which control heart rate: CAC - cardioaccelaratory centre - sympathetic fibres - increase heart rate CIC - cardioinhibitory centre - parasympathetic fibres - decreases heart rate.

Question 52

what is the cardioaccelaratory centre?

Answer 52

CAC in medulla has sympathetic fibres which release noradrenaline and innervates the sinoatrial node, atrioventricular node and the myocardium. causes an increase in heart rate and the strength of contraction

Question 53

what is the cardioinhibitory centre?

Answer 53

CIC in medulla has parasympathetic fibres which release acetylcholine and use the vagus nerve to innervate the sinoatrial node and the atrioventricular node causes a decrease in heart rate and the strength of contraction.