Circulatory System

Question 1

can single-celled organisms gain oxygen and glucose directly

Answer 1

Single-celled organisms can gain oxygen and glucose directly from their surroundings, and the molecules can diffuse to all parts of the cell quickly due to short diffusion distances

Question 2

Why do larger organisms require mass transport system

Answer 2

The diffusion distances involved are too great
Large organisms often have high energy requirements, so the delivery of reactants for metabolism needs to happen quickly

Question 3

what does mass transport system allow

Answer 3

Bring substances quickly from one exchange site to another
Maintain diffusion gradients at exchange sites
Ensure effective cell activity by supplying reactants and removing waste products

Question 4

how are atoms composed in water

Answer 4

hydrogen and oxygen. One atom of oxygen combines with two atoms of hydrogen by sharing electrons; this is covalent bonding
The sharing of the electrons is uneven between the oxygen and hydrogen atoms

Question 5

what does oxygen atom attract in H2O bond

Answer 5

he oxygen atom attracts the electrons more strongly than the hydrogen atoms, resulting in a weak negatively charged region on the oxygen atom (δ-) and a weak positively charged region on the hydrogen atoms (δ+)
This separation of charge due to the electrons in the covalent bonds being unevenly shared is called a dipole
When a molecule has one end that is negatively charged and one end that is positively charged it is said to be a polar molecule
Water is a polar molecule

Question 6

why does water dipole nature make it good at transporting

Answer 6

Water is cohesive making it good to transport substances
Water is a solvent

Question 7

explain cohesion and adhesion in water

Answer 7

Hydrogen bonds between water molecules allow for strong cohesion between water molecules
Water is also able to hydrogen bond to other molecules; this is known as adhesion

The forces of cohesion and adhesion within a body of water and between water and its surroundings means that water flows easily

Question 8

why is water a solvent

Answer 8

since polar molecule many ions will dissolve in it

Water molecules surround charged particles; the positive parts of water are attracted to negatively charged particles and the negative parts of water are attracted to positively charged particles
The surrounded molecules break apart
The ions surrounded by water molecules have dissolved

Question 9

what happens in closed circulatory system

Answer 9

blood is pumped around the body and is always contained within a network of blood vessels

Question 10

what happens in open circulatory system

Answer 10

the blood, or blood equivalent, is inside the body cavity and bathes the organs

Question 11

what does the right side of the heart pump

Answer 11

deoxygenated blood to the lungs for gas exchange; this is the pulmonary circulatory system

Question 12

what does the left side of the heart pump

Answer 12

Blood then returns to the left side of the heart, so that oxygenated blood can be pumped at high pressure around the body; this is the systemic circulatory system

Question 13

what is the heart divided into

Answer 13

four chambers
The two top chambers are atria
The bottom two chambers are ventricles

Question 14

what are the left and ride side of the heart separated by

Answer 14

a wall of muscular tissue called the septum

Question 15

what are the right atrium and right ventricle separated by

Answer 15

atrioventricular (AV) valve known as the tricuspid valve

Question 16

what are the left atrium and ventricle separated by

Answer 16

another AV known as the bicuspid valve

Question 17

what are right ventricle and pulmonary artery separated by

Answer 17

semilunar valve known as pulmonary valve

Question 18

what are left ventricle and aorta seperated by

Answer 18

another SL valve known as the aortic valve

Question 19

what are valves attached to

Answer 19

heart walls by valve tendons, or cords; these prevent the valves from flipping inside out under high pressure

Question 20

what is the function and structure of the left ventricle

Answer 20

thicker muscle than right for strong contraction to pump blood around the body.

Question 21

what is the function of AV valves

Answer 21

prevent back flow of blood from ventricles to atria

Question 22

what is the function of the semi lunar valves

Answer 22

prevent back flow of blood from aorta or pulmonary artery to the ventricles

Question 23

what two blood vessels bring blood into heart

Answer 23

vena cava: blood from body
pulmonary vein: from lungs

Question 24

what two blood vessels take blood away from the heart

Answer 24

The pulmonary artery takes blood to the lungs
The aorta takes blood to the body

Question 25

what is coronary arteries

Answer 25

a series of blood vessels in the muscle of the heart

Question 26

what are arterioles

Answer 26

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

Question 27

what are venules

Answer 27

these narrow blood vessels transport blood from capillaries into veins

Question 28

what blood vessel has narrow lumen and wider lumen

Answer 28

arteries have narrow lumen and veins have wider lumen

Question 29

what is the endothelium in artieries

Answer 29

once cell thick and lines the lumen. Very smooth and reduces friction for blood flow. Folded enabling it to expand under high pressure.

Question 30

Do arteries have smooth muscle and elastic tissue

Answer 30

This layer is thick in arteries The layer of muscle cells strengthen the arteries so they can withstand high pressure It also enables them to constrict and narrow the lumen for reduced blood flow

Question 31

what does contraction of the muscle cause

Answer 31

constriction of the lumen This is useful for diverting blood flow away from certain locations

Question 32

what does elastic tissue help

Answer 32

maintain blood pressure in the arteries It stretches and recoils to even out any fluctuations in pressure

Question 33

what does outer wall of artery contain

Answer 33

Contains the structural protein collagen protects blood vessels from damage by over-stretching

Question 34

why is smooth muscle layer and elastic layer thinner in veins

Answer 34

no need for a thick muscular layer as veins don't have to withstand high pressure

Question 35

how structure of vein relate to its function

Answer 35

A larger lumen helps to ensure that blood returns to the heart at an adequate speed preventss resistance to blood flow back to the heart valves prevent backflow of blood thin layer of muscular and elastic tissue to maintain blood pressure smooth endothelium to prevent resistance to blood flow

Question 36

why is there no pulse in veins

Answer 36

increased distance from the heart

Question 37

why do capillaries have a narrow lumen

Answer 37

Red blood cells need to pass through the capillaries in single file This forces the blood to travel slowly which provides more time for diffusion to occur

Question 38

structure of capillary walls

Answer 38

wall of the capillary is a single layer of endothelial cells This layer also lines the lumen in arteries and veins The wall is only one cell thick; this reduces the diffusion distance for oxygen and carbon dioxide between the blood and the tissues of the body

Question 39

what is the contraction/relaxation of the heart called

Answer 39

systole and diastole

Question 40

what are the volume and pressure changes during systole and diastole

Answer 40

Contraction of the heart muscle causes a decrease in volume in the corresponding chamber of the heart, which then increases again when the muscle relaxes Volume changes lead to corresponding pressure changes When volume decreases, pressure increases When volume increases, pressure decreases Throughout the cardiac cycle, heart valves open and close as a result of pressure changes in different regions of the heart

Question 41

explain atrial systole

Answer 41

The walls of the atria contract Atrial volume decreases Atrial pressure increases The pressure in the atria rises above that in the ventricles, forcing the atrioventricular (AV) valves open

Question 42

explain ventricular systole

Answer 42

The walls of the ventricles contract. The pressure in the ventricles rises above that in the atria. This forces the AV valves to close, preventing back flow of blood. The pressure in the ventricles rises above that in the aorta and pulmonary artery This forces the semilunar (SL) valves open so blood is forced into the arteries and out of the heart. Relaxed atria begin to fill with blood again

Question 43

Explain Diastole

Answer 43

The ventricles and atria are both relaxed The pressure 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 44

why are daphnia suitable to investigate effect of caffeine on heart rate

Answer 44

having transparent bodies; their internal organs, such as the heart, can be observed using a light microscope

Question 45

what is the method to investigate effect of caffeine on heart rate

Answer 45

- five different concentrations of caffeine and control of distilled water - add cotton wool on slide and add daphnia using pipette and add some distilled water - use stop clock to time a minute and record number of heartbeats/ dots on paper - repeat with different concentrations and daphnia

Question 46

results of daphnia experiment

Answer 46

caffeine increases heart rate of Daphnia by release of stimulatory neurotransmitters.

Question 47

steps of atherosclerosis

Answer 47

Damage by high blood pressure, is caused to the endothelium inflammatory response occurs and white blood cells such as macrophages accumulate in the damaged area Lipids and cholesterol clump together with macrophages under endothelium and form fatty streaks platelets (fragments of blood cells) can add to fatty deposit. Platelets, cholesterol lipids and macrophages accumulate under endothelium forming plaque knows as atheroma. This plaque can harden reducing elasticity of artery wall and increasing blood pressure

Question 48

what is the process of blood clotting known as

Answer 48

thrombosis

Question 49

steps of thrombosis

Answer 49

damaged blood vessels release protein called thromboplastin calcium ions from plasma and thromboplastin trigger conversion of soluble prothrombin into enzyme thrombin thrombin catalyses conversion of soluble protein fibrinogen into insoluble protein protein fibrin. fibrin fibres mesh and tangle trapping platelets and red blood cells blood clot formed

Question 50

how can atheroma increase risk of blood clotting

Answer 50

plaque deposit rupture through endothelium damaging it and forming rough surface triggering thrombosis

Question 51

why is atheroma and blood clotting dangerous

Answer 51

blood clot that forms can completely block the artery Blood clots reduce blood flow which restricts the movement of oxygen in the blood, therefore reducing respiration of the surrounding cells, tissues and organs if they reach the brain this can cause a stroke to occur Heart attack Deep vein thrombosis

Question 52

How is coronary hear disease caused

Answer 52

formation of atheroma and blood clots in the coronary arteries Blood flow to certain areas of the heart is restricted and delivery of oxygen to the affected cells decreases, thereby reducing respiration in these cells The cells can no longer produce ATP The cells can no longer contract, reducing the force generated by the heart when it beats The cells can die, causing permanent damage to heart tissue leading to heart attack

Question 53

two factod to control with caffeine and ghost shrimps

Answer 53

temperature of solution if too cold can decrease heart rate same size so caffeine affect equally

Question 54

why will a mammal born with a hole between ventricles have lack of energy

Answer 54

deoxygenated and oxygenated blood will mix as the deoxygenated blood from right ventricle will be transferred to left ventricle reducing the concentration of oxygen in the blood circulating around the body and to respiring tissues and muscle cells hence less oxygen for aerobic respiration

Question 55

control for daphnia investigation

Answer 55

use distilled water only no caffeine to show that the solvent had no effect on heart rate and to compare with caffeine concentrations

Question 56

how does blood clot cause heart attack

Answer 56

blood clot can clog/block the artery so oxygen cannot reach the heart/muscle cells preventing aerobic respiration from occurring. Therefore cardiac muscles cant contract

Question 57

myogenic

Answer 57

stimulation generated within the muscle resulting in depolarisation

Question 58

How does SAN ensure oxygenated blood enters aorta | sinoatrial

Answer 58

initiates impulses and electrical activity over atria causes atria to contract and pump oxygenated blood into left ventricle. Electrical activity from the SAN causes left ventricle to contract.

Question 59

four differences between arteries and capillaries

Answer 59

capillaries are one cell thick / arteries have multiple layers arteries contain collagen and capillaries dont lots of muscle in arteries no muscle in capilaries pores in capillaries none in arteries elastic tissue in arteries none in capillaries lumen one cell wide in capillaries

Question 60

why does frequent use of cocaine increase blood clot formation von willebrand fibrinogen

Answer 60

idea that von Willebrand factor results in platelets sticking to {the endothelium /each other}; 2. reference to release of thromboplastin (from platelets) ; 3. (as a result) the blood clotting process is triggered / eq; 4. credit one correct detail of clotting process; 5. reference to more fibrinogen resulting in the clot {being larger / growing faster } ; 6. reference to von Willebrand factor making the platelets stickier; 7. as a result of {platelet stickiness /platelets sticking together} the {clot grows faster / blood flow is decreased / eg} ; 8. If the blood is flowing slower then there is an increased chance of blood clotting / eq;

Question 61

why is water a good transport medium

Answer 61

it is a solvent so it can surround polar molecules and form hydrogen bonds. water is a liquid so it can flow

Question 62

left side of heart structure in comparison to right side

Answer 62

aorta which has thicker layer of muscular tissue / collagen and elastic tissue collagen withstands high blood pressure muscular tissue maintains high blood pressure and elastic tissue recoils to maintain blood pressure

Question 63

Describe how av valves work in one cardiac cycle

Answer 63

the valves are open { when atria contract / atrial systole / when blood pressure greater in atria (than ventricles) } (1) • the valves close { when ventricles contract / during ventricular systole/when pressure greater in ventricles (than atria) } (1) • valves prevent backflow of blood into the atria during ventricular systole (1)

Question 64

explain how a blood clot can cause a heart attack

Answer 64

prevents oxygen reaching the heart {muscle / cells / tissue / eq}; prevents (aerobic) respiration; (cardiac) muscle unable to contract / dies / eq } ;

Question 65

two differences between fibrin and fibrinogen

Answer 65

Idea that fibrinogen is globular and fibrin is fibrous; . fibrinogen is soluble and fibrin is insoluble

Question 66

what happens during diastole

Answer 66

atria and ventricles relax blood enters atria semilunar close and atrioventricular open

Question 67

Describe the roles of the atrioventricular (bicuspid and tricuspid) valves during the cardiac cycle.

Answer 67

valves {separate / eq} atria from ventricles ; 2. open during atrial {systole / contraction } / eq ; 3. so that blood can pass through to ventricles / eq ; 4. closed during ventricular {systole / contraction} eq ; 5. to prevent {blood being forced back / backflow / eq} (up into atria) / to maintain pressure in ventricles ; 6. open during diastole / eq ; 7. so that ventricles can start to fill up (as atria are filling)

Question 68

Describe the structure of collagen.

Answer 68

primary structure described as a repeating amino acid sequence (1)  three polypeptide chains (1)  chains coiled around each other (1)  cross-linking between the chains