TRANSPORT IN HUMANS

Question 1

The cardiovascular system is made up of:

Answer 1

• the heart
• blood vessels
• blood

Question 2

what is systemic circulation?

Answer 2

when blood is pumped out of the left ventricle through the aorta traveling to the whole body (except lungs) and then returns to the heart through vena cava

Question 3

what is pulmonary circulation?

Answer 3

when blood is pumped out of the right ventricle through the pulmonary artery and travels to the lungs then returns to the heart by pulmonary veins

Question 4

what are arteries, veins and capillaries?

Answer 4

arteries: take blood away from the heart
veins: take blood into the heart
capillaries: link arteries and veins to bring the blood as close to cells as possible for faster diffusion

Question 5

what are the 3 blood vessel layers?

Answer 5

tunica intima (inner coat)
tunica media (middle coat)
tunica externa (outer coat)

Question 6

what is tunica intima?

Answer 6

inner coat

made up of squamous epithelium which is smooth to reduce friction

Question 7

what is tunica media?

Answer 7

middle coat

made up of elastic fibers and some collagen fibers

Question 8

what is tunica externa?

Answer 8

outer coat

made up of collagen and some elastic fibers

Question 9

what is the structure of an artery?

Answer 9

thick wall
narrow lumen to increase blood pressure

tunica media has a lot of elastic fibers to allow the arterial wall to stretch as blood passes through with high pressure making it wider and reduce the pressure slightly so that the artery doesn’t burst

tunica externa has a lot of collagen fibers to provide strength

Question 10

what is the structure of arterioles?

Answer 10

are smaller than arteries
branch off arteries
have more smooth muscle which allows them to constrict and control the blood flow of capillaries

Question 11

what is the structure of veins?

Answer 11

thin walls
wide lumen

tunica media is very thin and contains fewer elastic and collagen fibers than arteries

Question 12

how does blood flow through veins?

Answer 12

contraction of skeletal muscles:
by contracting they would squeeze the nearby vein increasing the pressure

valves:
prevent backflow of blood away from the heart

Question 13

what is the structure of venules?

Answer 13

drain blood from capillaries and bring it to veins

contains small muscle that allows it to constrict and control blood flow through capillaries

Question 14

what is the structure of capillaries?

Answer 14

smallest blood vessel
form capillary beds that bring blood as close to cells as possible
one cell thick allowing efficient diffusion
narrow lumen so only one RBC can pass through at a time allowing more time for substances to diffuse in and out

Question 15

what are the heart chambers and what do they receive and pump?

Answer 15

left atrium: receives oxygenated blood from the lungs through the pulmonary vein and pumps it to the left ventricle

left ventricle: receives oxygenated blood and pumps it to the whole body through the aorta

right atrium: receives deoxygenated blood from the whole body through the vena cava and pumps it to the right ventricle

right ventricle: receives deoxygenated blood and pumps it to the lungs through the pulmonary artery

Question 16

what are the hearts vessels?

Answer 16

aorta: pumps oxygenated blood from heart to body tissues

pulmonary vein: transports oxygenated blood from lungs to heart

superior vena cava: transports deoxygenated blood from the upper body to the heart

inferior vena cava: transports deoxygenated blood from the lower body to the heart

pulmonary arteries: transports deoxygenated blood from the heart to lungs

coronary vessels: branch from aorta and supply the heart with blood for it to respire and release energy to contract and pump blood

Question 17

why are ventrical walls thicker than atrium walls?

Answer 17

because ventricles transport and pump blood outside of the heart with high pressure and atria only pump blood to the ventricles

Question 18

why is the left ventricles wall thicker than the right ventricle?

Answer 18

because the left ventricle pumps blood with a higher pressure to the whole body whilst the right ventricle pumps blood to the nearby lungs

Question 19

what’re the adaptations of red blood cells?

Answer 19

they’re very small (7Mm): makes it easy to squeeze through capillaries

biconcave-disc shape: which increases surface area therefor increasing rate of diffusion

have no nucleus or organelles: allowing more space for hemoglobin to carry the max amount of oxygen

large amount of hemoglobin: to transport oxygen

Question 20

how is tissue fluid formed?

Answer 20

as blood flows from arteries to capillaries, the high pressure forces water and small molecules out of the capillary wall into the spaces between tissues forming tissue fluid

Question 21

where does tissue fluid leave and enter capillaries?

Answer 21

tissue fluid tends to leave the capillaries at the arterial end and enter back at its venous end

Question 22

what are the two pressures inside capillaries?

Answer 22

blood pressure entering the capillary forces water and small molecules out of the capillary wall

osmotic pressure brings water back into the capillary as the plasma proteins that remain in the blood create low water potential inside the capillary drawing water back in by osmosis

Question 23

what is lymph and how is it formed?

Answer 23

not all tissue fluid is returns to the capillaries, the excess drains into the lymphatic system by lymph vessels forming lymph

lymph enters the lymphatic vessel through valves that allow it to enter but not exit

lymph passes through lymph nodes which contain WBC’s that filter the lymph trapping pathogens

Question 24

blood, tissue fluid and lymph:

Answer 24

blood:
present in vessels
made up of plasma, RBC’s, WBC’s and platelets
transports substances around the body

tissue fluid:
present around tissues
similar to blood but has less proteins and no RBC’s
provides tissues with oxygen and nutrients and removes carbon dioxide and waste

lymph:
present in lymphatic vessels
no RBC’s, WBC’s present from lymph nodes and has less oxygen and now fats
carries fluid from tissues to heart

Question 25

what is the cardiac cycle?

Answer 25

the sequence of events which makes up 1 heartbeat

Question 26

what happens in arterial systole?

Answer 26

the arterial muscle contracts and ventricular muscle relaxes

the pressure in atria forces blood through the AV valves into the ventricles

semilunar valves close to prevent back flow of blood

Question 27

what is ventricular systole?

Answer 27

ventricular muscle contracts and arterial muscle relaxes

the pressure in ventricle is more than in the atrium which pushes the AV valves shit and pushes open the semilunar valves flowing the blood into the arteries

Question 28

what is ventricular diastole?

Answer 28

ventricular and arterial muscles relax and as pressure drops, the atria will fill with the blood and semilunar valves will close

as pressure in the atria increases, AV valves open and blood flows into the ventricles