circu;atory system save my exams

Question 1

need for a ciruclatory system

Answer 1

constant supply of reactants for metabolism
oxygen and glucose directly from their surroundings, and the molecules can diffuse to all parts of the cell quickly due to short diffusion distances
mass transport system, for example
The digestive system is connected to the circulatory system

Question 2

definition mass transport

Answer 2

bulk movement of gases or liquids in one direction, usually via a system of vessels and tubes

Question 3

closed circulatory system

Answer 3

blood is pumped around the body and is always contained within a network of blood vessels
All vertebrates and many invertebrates have closed circulatory systems

Question 4

systematic closed circulatory system

Answer 4

Humans have a closed double circulatory system: in one complete circuit of the body, blood passes through the heart (the pump) twice
The right side of the heart pumps blood deoxygenated blood to the lungs for gas exchange; this is the pulmonary circulatory system
Blood then returns to the left side of the heart, so that oxygenated blood can be pumped efficiently (at high pressure) around the body; this is the systemic circulatory system

Question 5

pulmonary artery

Answer 5

carries deoxygenated blood away from the heart, towards the lungs

Question 6

pulomary vein

Answer 6

carries oxygenated blood away from the lungs, towards the heart

Question 7

coronary arteries

Answer 7

supply the heart with oxygenated blood

Question 8

aorta

Answer 8

carries oxygenated blood out of the heart and to the rest of the body

Question 9

vena cava

Answer 9

carries deoxygenated blood into the heart

Question 10

renal artery

Answer 10

supplies the kidneys with oxygenated blood

Question 11

renal vein

Answer 11

carries deoxygenated blood away from the kidneys, towards the heart

Question 12

when do valves in the heart open

Answer 12

when the pressure of blood behind them is greater than the pressure in front of them

Question 13

when do valves in the heart close

Answer 13

when the pressure of blood in front of them is greater than the pressure behind them

Question 14

why are vealves important

Answer 14

keeping blood flowing forward in the right direction and stopping it flowing backwards. They are also important for maintaining the correct pressure in the chambers of the heart

Question 15

atrioventricularvalve

Answer 15

The right atrium and right ventricle are separated by the atrioventricular valve,

Question 16

pulmonary valve

Answer 16

The right ventricle and the pulmonary artery are separated

Question 17

bicuspid valve

Answer 17

The left atrium and left ventricle are separated by the mitral valve, which is otherwise known as

Question 18

vena cava and pul vein

Answer 18

bringing blood to the heart;

Question 19

two blood vessels taking blood away from the heart

Answer 19

pulmonary artery and aorta

Question 20

coronary arteries

Answer 20

The heart is a muscle and so requires its own blood supply for aerobic respiration
The heart receives blood through arteries on its surface, called coronary arteries
It’s important that these arteries remain clear of plaques, as this could lead to angina or a heart attack

Question 21

why the left ventricle is thicker

Answer 21

blood leaving the right ventricle travels less distance than blood leaving the left ventricle
The blood pumped out from the right ventricle travels to the lungs, whereas blood leaving the left ventricle has to travel to the rest of the body to deliver oxygen for respiration.
To reach the rest of the body, the blood leaving the left ventricle must be under high pressure
This is generated by the contraction of the muscular walls of the left ventricle
The right ventricle generates less pressure from the contraction of its thinner walls, as blood only has to reach the lungs

Question 22

why left atrium is thinner

Answer 22

pressure generated by their contraction is low. Low pressure is sufficient because blood is forced only a short distance; from the left atrium down to the left ventricle. The muscular walls of the left ventricle are much thicker and generate much higher pressure, as shown on the graph. This is because much more pressure is generated when this thick muscle contracts and squeezes blood with enough force to reach the rest of the body

Question 23

contraction

Answer 23

decrease in volume in the corresponding chamber of the heart, which then increases again when the muscle relaxes

Question 24

when volume decreases what happens to pressure

Answer 24

increases

Question 25

valves and pressure

Answer 25

Valves open when the pressure of blood behind them is greater than the pressure in front of them They close when the pressure of blood in front of them is greater than the pressure behind them Valves are an important mechanism to stop blood flowing backwards

Question 26

atrial systole

Answer 26

walls of the atria contract Atrial volume decreases Atrial pressure increases forcing the atrioventricular (AV) valves open Blood is forced into the ventricles There is a slight increase in ventricular pressure and chamber volume as the ventricles receive the blood from the atria ventricles are relaxed at this point; ventricular diastole coincides with atrial systole

Question 27

ventricular systole

Answer 27

walls of the ventricles contract Ventricular volume decreases Ventricular pressure increases forces the AV valves to close, preventing back flow of blood pressure in the ventricles rises SL) valves open so blood is forced into the arteries and out of the heart

Question 28

diastole

Answer 28

entricles and atria are both relaxed ressure in the ventricles drops below that in the aorta and pulmonary artery, forcing the SL valves to close The atria continue to fill with blood Blood returns to the heart via the vena cava and pulmonary vein Pressure in the atria rises above that in the ventricles, forcing the AV valves open Blood flows passively into the ventricles without need of atrial systole The cycle then begins again with atrial systole

Question 29

what happens to atriventricular valves and semi lunar in atrial systole

Answer 29

open closed

Question 30

what happens to atrioventricylar valves and semi lunar valves in ventricular systole

Answer 30

closed open

Question 31

what happens to atrioventricular valves and semi lunar valves in diastoled

Answer 31

open closed

Question 32

arteries

Answer 32

transport blood away from the heart

Question 33

veins

Answer 33

ransport blood to the heart

Question 34

arterioles

Answer 34

arteries branch into narrower blood vessels called arterioles which transport blood into capillaries

Question 35

artery strcutre

Answer 35

wall of the artery is relatively thick with layers of collagen, smooth muscle and elastic fibres The elastic fibres allow the artery wall to expand around blood surging through at high pressure when the heart contracts, these fibres then recoil when the heart relaxes – this alongside a narrow lumen maintains high blood pressure

Question 36

vein strucutre

Answer 36

wall of the vein is relatively thin with thinner layers of collagen, smooth muscle and elastic fibres The lumen of the vein is much larger than that of an artery Veins contain valves that prevent the backflow of blood, helping return blood to the heart

Question 37

arterioles structure

Answer 37

lower proportion of elastic fibres and a large number of muscle cells The presence of muscle cells allows them to contract and close their lumen to stop blood flow

Question 38

strucutre of capillaries

Answer 38

very small diameter (lumen) branch between cells Substances can diffuse between the blood and cells quickly as there is a short diffusion distance only one cell thick cells of the wall have gaps called pores which allow blood plasma to leak out and form tissue fluid

Question 39

formation of tissue. fluid

Answer 39

hydrostatic pressure is great enough to push molecules out of the capillary Proteins remain in the blood; the increased protein content creates a water potential between the capillary and the tissue fluid However, overall movement of water is out from the capillaries into the tissue fluid

Question 40

what is tissue fluid

Answer 40

Exchange of substances between cells and the blood occurs via the tissue fluid For example, carbon dioxide produced in aerobic respiration will leave a cell, dissolve into the tissue fluid surrounding it, and then diffuse into the capillary