Section 3- Circulatory system

Question 1

What does double circulation mean?

Answer 1

Blood passes through the heart twice in every circulation of the body

Question 2

What are the 2 circuits that make up the double circulation system in humans?

Answer 2

• Pulmonary circuit

- Systemic circuit

Question 3

What are the advantages of having double circulation?

Answer 3

• Oxygenated and deoxygenated blood do not mix

- Allows different blood pressures in the systemic and pulmonary circuits

Question 4

What is the name of the membranes encapsulated by the heart and what does it do?

Answer 4

Pericardium

Prevents over expansion

Question 5

What is the name of the walls of the heart?

Answer 5

Myocardium

Cardiac muscle

Question 6

What does myogenic mean?

Answer 6

The heart is able to generate its own electric activity

Question 7

What blood vessel joins the right ventricle of the heart to the capillaries of the lungs?

Answer 7

Pulmonary artery

Question 8

What blood vessel carries oxygenated blood away from the kidney?

Answer 8

Renal vein

Question 9

What is the first main blood vessel that an oxygen molecule reaches after being absorbed from an alveolus?

Answer 9

Pulmonary vein

Question 10

What are the names of the valves located between the atrium and ventricle?

Answer 10

Atrioventricular valves

Question 11

What are the valves for?

Answer 11

Preventing back-flow of blood

Question 12

What is the aorta?

Answer 12

Connected to left ventricle

Carries oxygenated blood to the body

Question 13

What is the vena cava?

Answer 13

Connected to right atrium

Brings deoxygenated blood back from the tissues to the heart

Question 14

What is the pulmonary artery?

Answer 14

Connected to right ventricle

Carries deoxygenated blood to the lungs

Question 15

What is the pulmonary vein?

Answer 15

Connected to left atrium

Brings oxygenated blood back from lungs to heart

Question 16

What are the coronary arteries?

Answer 16

The blood vessels that are supplied to the heart muscle

Question 17

What is the cardiac cycle?

Answer 17

Sequence of events in 1 heartbeat

Question 18

What are the 2 alternate beating phases of the heart called and what do they mean?

Answer 18

Systole = contraction

Diastole = relaxation

Question 19

What controls the opening of valves?

Answer 19

Pressure in the relative chambers

Question 20

What is atrial systole?

Answer 20

Contraction of atrial walls
Relaxation of ventricle walls

Forces remaining blood into ventricles from atria

Question 21

What is ventricular systole?

Answer 21

Walls of ventricle contract whilst filling with blood
Increases blood pressure
Forces AV valves shut

Question 22

What is ventricular diastole?

Answer 22

Atria and ventricle are relaxed
Blood returns to atria
As atria fills, pressure rises.

When pressure exceeds ventricles, AV valves open allowing blood into ventricles
SL valves shut as pressure is reduced from relaxation and recoil

Question 23

When are the AV valves open?

Answer 23

Atrial systole

Diastole

Question 24

When are the SL valves open?

Answer 24

Ventricular systole

Question 25

When are the AV valves closed?

Answer 25

Ventricular systole

Question 26

When are the SL valves closed?

Answer 26

Atrial systole | Diastole

Question 27

What is cardiac output?

Answer 27

The volume of blood pumped around the body

Question 28

what is stroke volume?

Answer 28

Volume of blood pumped by the ventricle in each heart beat

Question 29

What is heart rate?

Answer 29

Number of times heart beats per minute

Question 30

How do you calculate cardiac output?

Answer 30

Heart rate X stroke volume

Question 31

How would an asthma attack cause the drop in the mean FEV?

Answer 31

- Muscle walls of bronchi contract - Walls of bronchi secrete more mucus - Diameter of airways reduced - Flow of air reduced

Question 32

Why do the semi-lunar valves open?

Answer 32

Pressure in ventricles exceeds pressure in the atrium

Question 33

Why do the atrioventricular valves open?

Answer 33

Pressure in atria exceeds pressure in ventricles

Question 34

What is the basic layering of arteries and veins?

Answer 34

Tunica adventitia -Outer layer containing collagen/ elastic fibres Tunica media -Middle layer containing smooth muscle and elastic fibres Tunica intima -Endothelium (single layer of cells) Lumen -Hollow centre of tube

Question 35

What are the specialised structure/ features of arteries?

Answer 35

Thick walls -Transports blood at high pressure Collagen and elastic fibres in walls -Ensures blood remains at high pressure Tick walls = narrow lumen

Question 36

What are the specialised structure/ features of arterioles?

Answer 36

Lower pressure of blood Thinner walls with elastic tissue (smooth muscle) -Allows constrict and regulate blood flow to different areas of body

Question 37

What are the specialised structure/ features of veins?

Answer 37

- Low pressure of blood - Thinner walls - Wide lumen - Contains valves preventing backflow

Question 38

What are the specialised structure/ feature of capillaries?

Answer 38

One cell thick -Reduce diffusion distance Take blood close to all cells to deliver and remove substances

Question 39

What is tissue fluid?

Answer 39

Liquid that surrounds all cells

Question 40

What is tissue fluid the result of the balance between?

Answer 40

- Hydrostatic pressure | - Osmotic pressure

Question 41

What are the 3 types of tissue fluid?

Answer 41

Tissues fluid Blood Lymph

Question 42

When does hydrostatic pressure occur?

Answer 42

Due to volume of blood pushing against walls of blood vessels

Question 43

What is osmotic pressure?

Answer 43

A net loss of water from capillaries

Question 44

How is tissue fluid formed?

Answer 44

1. Hydrostatic pressure forces fluid out of the capillaries a the arterial end Dissolved gases and nutrients move with it Large plasms and proteins and cells do not 2. Osmotic pressure: net loss of water from capillaries (due to hydrostatic pressure) gives blood more negative water potential Water moves down water potential gradient into capillaries by osmosis 3. Not all fluid passes back into capillaries Excess output needs to be collected to avoid tissues swelling Net excess is drained into vessels of lymphatic system (the lymph) Lymph drains back into circulatory system

Question 45

What is the pressure division at the arterial end of the vessel?

Answer 45

hydrostatic pressure > osmotic pressure

Question 46

What is the pressure division at the venous end of the vessel?

Answer 46

osmotic pressure > hydrostatic pressure

Question 47

Why does tissue fluid accumulate in tissues of people who do not eat enough protein?

Answer 47

Less protein causes water potential to not become as negative so less water can be absorbed

Question 48

How can blood cholesterol increase the risk of cardiovascular disease?

Answer 48

Low-density lipoproteins: transport cholesterol from liver to tissues - leads to development of atheroma which leads to heart disease

Question 49

How can diet increase the risk of cardiovascular disease?

Answer 49

High levels of salt raise blood pressure High levels of saturated fat increase low-density lipoprotein levels hence blood cholesterol concentration

Question 50

What is an atheroma?

Answer 50

Build up of fatty acid deposits, which forms within the endothelium of an artery Can lead to thrombosis or an aneurysm

Question 51

What is a stroke?

Answer 51

When an artery in the brain bursts and blood leaks into the brain tissue Brain tissue becomes starved of oxygen

Question 52

How does high blood pressure lead to an accumulation of tissue fluid?

Answer 52

High blood pressure = High hydrostatic pressure Increased outward pressure from arterial end of capillary More tissue fluid formed

Question 53

Why is water potential of blood plasma more negative at venule end of capillary than arteriole end?

Answer 53

Water has left capillary Proteins in blood are too large to leave capillary Increasing higher concentration of blood proteins

Question 54

How do capillaries running over the surface of the alveoli improve efficiency of gaseous exchange?

Answer 54

Delivers carbon dioxide to alveoli | Carrier oxygen away

Question 55

What is the type of muscle found in the walls of the heart chambers?

Answer 55

Cardiac muscle

Question 56

What is the process that creates pressure inside the heart chambers?

Answer 56

Contraction/ systole

Question 57

How can higher than normal concentration of salt in blood entering capillaries lead to build-up of tissue fluid?

Answer 57

Results in lower water potential of tissue fluid so less water returns to capillary by osmosis.

Question 58

How is the aorta adapted to its function?

Answer 58

Has folded inner lining Allows maintenance of high pressure Large muscular walls - contracting and recoiling