3.5 The Circulatory Systems in Animals

Question 1

Name the top two chambers of the heart.

Answer 1

Atria

Question 2

Name the bottom two chambers of the heart.

Answer 2

Ventricles

Question 3

What separates the atria from the ventricles?

Answer 3

Atrioventricular valves

Question 4

What separates the ventricles from the arteries?

Answer 4

Semi lunar valves

Question 5

What does the aorta carry?

Answer 5

Oxygenated blood from the left ventricle to cells in the body

Question 6

What does the pulmonary artery carry?

Answer 6

Deoxygenated blood from the right atrium to the lungs

Question 7

What does the vena cava carry?

Answer 7

Deoxygenated blood from the cells in the body to the right atrium

Question 8

What does the pulmonary vein carry?

Answer 8

Oxygenated blood from the lungs to the left side atrium

Question 9

Name 2 arteries.

Answer 9

Pulmonary artery
Aorta

Question 10

Name 2 veins.

Answer 10

Pulmonary vein
Vena cava

Question 11

What is pulmonary relevant to?

Answer 11

The lungs

Question 13

Describe the path of blood through the heart.

Answer 13

Into atria
Into ventricles
Up into artery

Question 14

How is blood pushed around the body?

Answer 14

By putting pressure on it

Question 15

How is the pressure changed in the heart chambers?

Answer 15

By contracting them to reduce their size and increase their pressure

Question 16

What is the first stage of the cardiac cycle?

Answer 16

Diastole
Both atria and ventricles are relaxed

Question 17

Describe the pressure in the atria and ventricles in the first stage of the cycle.

Answer 17

Low pressure as space inside them is maximum
Ventricle pressure is slightly lower than atria due to the naturally bigger size

Question 18

Where is blood flowing the first stage of the cardiac cycle?

Answer 18

From higher pressure in vein to lower pressure in atrium and ventricle

Question 19

What is the second stage of the cardiac cycle?

Answer 19

Atrial systole (atria contract)

Question 20

Describe the pressure in the atria and ventricles in the second stage of the cycle.

Answer 20

Pressure in atrium is higher than ventricle as there is now less space

Question 21

Are the atrioventricular valves open or shut during the second stage of the cardiac cycle?

Answer 21

Open

Question 22

Where is the blood flowing during the second stage of the cardiac cycle?

Answer 22

Pushed from atrium to ventricle

Question 23

What is the third stage of the cardiac cycle?

Answer 23

Ventricular systole (venticles contract)

Question 24

Describe the pressure in the atria and ventricles in the third stage of the cycle.

Answer 24

Pressure in ventricle is much higher than pressure in atrium and as it contracts pressure gets higher than artery as well

Question 25

Are the atrioventricular valves open or shut in the third stage of the cycle?

Answer 25

Shut

Question 26

Where is the blood flowing during the second stage of the cardiac cycle?

Answer 26

From the ventricle into the artery

Question 27

Are the semi-lunar valves open or shut in the third stage of the cycle?

Answer 27

Open

Question 28

What is the first inside layer of a blood vessel called?

Answer 28

Endothelium

Question 29

What is the second layer of a blood vessel?

Answer 29

Elastic fibres

Question 30

What is the purpose of the second layer of a blood vessel?

Answer 30

Allows vessel to stretch and recoil to smooth flow

Question 31

What is the third layer of a blood vessel?

Answer 31

Muscular layer

Question 32

What is the purpose of the third layer of a blood vessel?

Answer 32

Allows vessel to contract and dilate to keep pressure on blood

Question 33

What is the final layer of a blood vessel?

Answer 33

Collagen fibres

Question 34

What is the purpose of the final layer of a blood vessel?

Answer 34

Add strength so they do not burst

Question 35

Describe two adaptations of the capillary wall that make it efficient at exchange.

Answer 35

One cell thick = short diffusion distance Pores/podocytes = small molecule can move

Question 36

Why are the endothelial cells of the capillary wall flattened?

Answer 36

Reduces diffusion distance

Question 37

Why is the lumen of the capillary narrow?

Answer 37

Reduces diffusion distance

Question 38

What is the purpose of fenestrations(openings) in the endothelium of the capillaries?

Answer 38

To allow larger molecules to pass in/out of capillary

Question 39

What is difference about the blood flowing through an artery compared to the blood flowing through a vein?

Answer 39

Higher pressure Smoother flow

Question 40

Describe the adaptations of an artery.

Answer 40

More elastic fibres so can recoil More muscle so can keep force on blood and change pressure More collagen for strength to resist high pressure

Question 41

Describe the adaptations of a vein.

Answer 41

Valves to keep blood flow in one direction - prevent backflow

Question 42

Which end of the capillary has the greatest blood pressure?

Answer 42

Arteriole end

Question 43

What kind of pressure is created by blood?

Answer 43

Hydrostatic

Question 44

What does the hydrostatic pressure created by the blood force?

Answer 44

Small molecules which are dissolved in plasma are forced out of blood into tissue

Question 45

Give examples of molecules dissolved in plasma that are forced out.

Answer 45

Glucose Amino acids

Question 46

What kind of molecules are forced out of the blood?

Answer 46

Small

Question 47

Why is it only small molecules forced out of the blood?

Answer 47

Capillaries only permeable to small molecules due to small pores in walls

Question 47

What kind of molecules aren't forced out of the blood?

Answer 47

Large proteins and red blood cells

Question 48

Why aren't large molecules forced out of the blood?

Answer 48

Too large to fit through pores

Question 49

What impact do large proteins have on the blood?

Answer 49

Reduce the water potential as they dissolve

Question 50

Why does tissue fluid return to the blood?

Answer 50

Osmosis due to water potential gradient and reduction of hydrostatic pressure of blood

Question 50

What happens to large proteins once in the tissue fluid?

Answer 50

Diffuse into cells

Question 50

What are cells constantly producing?

Answer 50

Carbon dioxide from respiration Urea from protein synthesis

Question 50

What is tissue fluid?

Answer 50

The fluid surrounding the cells of most tissues, arriving via blood capillaries and being removed via lymphatic vessels

Question 50

What happens to the carbon dioxide and urea produced in cells?

Answer 50

Diffuse into tissue fluid

Question 51

What happens to the 10% of tissue fluid that cannot return to blood?

Answer 51

Moves into lymphatic vessels

Question 52

What is lymph?

Answer 52

The tissue fluid after it enters the lymphatic vessels

Question 53

How is lymph fluid moved around the body?

Answer 53

Muscle contractions and hydrostatic pressure

Question 54

Why does a low protein diet result in a swollen stomach?

Answer 54

Increased water potential of blood means less fluid returns by osmosis

Question 55

Why does a high blood pressure result in swollen limbs?

Answer 55

Too much fluid is forced out of the capillaries and not enough returns

Question 56

Why can parasites lead to swelling?

Answer 56

Damage to lymphatic vessel lead to leakage of fluid