Mass Transport in Animals

Question 1

why is the circulatory system knows as a double system

Answer 1

the blood passes through the heart twice in one circuit

Question 2

what is the function of the vena cava

Answer 2

carries blood from body to heart

Question 3

what is the function of the pulmonary artery

Answer 3

carries blood from the heart to the lungs

Question 4

what is the function of the pulmonary vein

Answer 4

carries blood from the lungs to the heart

Question 5

what is the function of the aorta

Answer 5

carries blood from the heart to the body

Question 6

what is the function of the renal artery

Answer 6

carries blood from the body to the kidneys

Question 7

what is the function of the renal vein

Answer 7

carries blood from the kidneys to the vena cava

Question 8

diagram of heart

Answer 8

heart

Question 9

the right side of the heart receives …….. blood

Answer 9

deoxygenated

Question 10

the left side of the heart receives …… blood

Answer 10

oxygenated

Question 11

the right side of the heart receives blood by the …….

Answer 11

vena cava

Question 12

the left side of the heart receives blood by the ……

Answer 12

pulmonary vein

Question 13

what is the difference between the ventricles and the atria and what does this allow

Answer 13

the ventricles have thicker muscular walls which allows them to generate high pressure to pump blood out of the heart

Question 14

why do the atria not need as thick muscular walls as the ventricles

Answer 14

the atria just need to pump blood a short distance to the ventricles

Question 15

true or false

the right ventricle of the heart has thicker muscular walls

Answer 15

false
the left ventricle has thicker muscular walls

Question 16

explain why the left ventricle has thicker muscular walls than the right side

Answer 16

because the left ventricle has to pump blood all around the body whereas the right pumps blood to the lungs

Question 17

what is the role of valves

Answer 17

prevent backflow of blood

Question 18

heart valves open based on ……

Answer 18

the pressure of the heart chambers

Question 19

what are the 2 valves and what do they do

Answer 19

• atrioventricular (AV) - link the atria to the ventricles
• semilunar (SL) - link the pulmonary artery and aorta to the ventricles

Question 20

explain the process that leads to blood moving from the atrium into the ventricles

Answer 20

• the ventricles relax and have a low pressure
• the atria contract, causing the volume in the chambers to decrease and the pressure to increase
• the AV valve opens and blood enters the ventricles down a pressure gradient

Question 21

explain the process that leads to blood moving from the ventricles into the aorta and pulmonary vein

Answer 21

• atria relax and pressure decreases
• ventricles contract causing the volume to decrease and pressure to increase
• AV valves close
• SL valves open and blood is forced into the aorta and pulmonary artery

Question 22

explain the process that leads to the cardiac cycle repeating

Answer 22

• ventricles and atria relax
• pressure is higher in pulmonry artery and aorta
• SL valves close
• blood returns to the heart as the pressure in the vena cava and pulmonary vein is greater than in atria
• cycle repeats

Question 23

what is cardiac ouput

Answer 23

the volume of blood pumped by the heart per minute

Question 24

what is the equation to calculate cardiac ouput

Answer 24

cardiac ouput = stroke volume x heart rate

Question 25

define heartrate | include units

Answer 25

the number of beats per minute (bpm)

Question 26

define stroke volume | include units

Answer 26

the volume of blood pumped during each heartbeat (cm^3)

Question 27

what is the role of arteries

Answer 27

carry blood from the heart to the rest of the body

Question 28

explain 3 key features of arteries

Answer 28

* thick outer walls that can withstand pressure * elastic tissue to help stretch when the ventricles contract and recoil when the ventricle relaxes. This helps maintain pressure * they have an inner lining called endothelium which is smooth. This reduces friction

Question 29

what is the role of arterioles

Answer 29

arteries divide into smaller blood vessels which carry blood from arteries to capillaries under a lower pressure

Question 30

what is the role of veins

Answer 30

take blood back to the heart from the body

Question 31

what is the role of capillaries

Answer 31

* smallest blood vessels * site of substance exchange

Question 32

explain 4 key features of capillaries

Answer 32

* walls are one cell thick which allows for a short diffusion pathway * contains fenestrations which allows large molecules to leave the blood vessel * they have a narrow lumen which reduces flow rate, giving more time for diffusion * endothelial cells are smooth and flat, this reduces friction

Question 33

tissue fluid is formed from ......

Answer 33

blood plasma

Question 34

explain the formation of tissue fluid and how it is returned

Answer 34

* **in the arterial end:** * hydrostatic pressure inside the capillaries is higher than the tissue fluid * this pressure forces fluid out of the capillaries and into tissue space * proteins stay in the capillary becaue they are too large * this reduces the water potential of the capillary * hydrostatic pressure lowers * **in the venous end:** * hydrostatic pressure of the capillary is lower than the tissue fluid, therefore tissue is forced back into the capillaries * water re enters the capillary by osmosis * any tissue fluid that does not return to the capillary is drained away from the tissues by the lymphatic system * this fluid is referred to as lymph

Question 35

describe how tissue fluid is formed and how it is returned to the circulatory system (5 marks)

Answer 35

* high hydrostatic pressure * forces water / fluid out of the capillary * large proteins remain in capillary * these causes a low water potential in capillart * water enters capillary by osmosis * any tissue that does not return to the capillary is drained away and referred to as lymph

Question 36

what is cardiovascular disease

Answer 36

general term used to describe diseases associated with the heart and blood vessels

Question 37

what is coronary heart disease

Answer 37

any interference with the coronary arteries which supply blood to the heart muscle itself

Question 38

give 5 risk factors for heart disease

Answer 38

* age * gender * genetic factors * stress * smoking