circulatory system

Question 1

Describe the position of the heart within the mediastinum.

Answer 1

Obliquely in the mediastinum, medial to two lungs and superior to the diaphragm

Question 2

Superior chambers

Answer 2

collecting, atria, top of the heart and collect blood from the lungs

Question 3

Inferior chambers

Answer 3

discharging, ventricles, bottom of the heart and eject blood from the heart

Question 4

Left atrium

Answer 4

receive oxygenated blood returning from lungs through four openings
Four pulmonary veins 2 from each lung

Question 5

Left ventricle

Answer 5

received oxygenated blood from left atrium
Opens to aorta
Thickest walled chamber in the heart

Question 6

Right atrium

Answer 6

receives deoxygenated blood returning from the body

Question 7

Right ventricle

Answer 7

receives deoxygenated blood from right atrium
Opens to pulmonary trunk

Question 8

valves in the heart

Answer 8

Atrioventricular valves x 2 (tricuspid and bicuspid)
Semilunar valves x2 (pulmonary and aortic)

Question 9

Atrioventricular valves

Answer 9

valve between atria and ventricles
Have cusps attached to papillary muscles by tendons = chordae tentineae
Right side has three cusps
Left side has two cusps
When the valve is open blood flows from the atrium to ventricle

Question 10

Semilunar valves

Answer 10

valves at the exit of ventricles
Pulmonary semilunar valve = at base of pulmonary trunk
Aortic semilunar valve = at the base of the aorta

Question 11

function of valves in the heart

Answer 11

prevent back flow of blood

Question 12

Chordae tendineae

Answer 12

strings connecting valve cusps to papillary muscles preventing the valves from bulging into aorta

Question 13

Papillary muscles

Answer 13

muscles in ventricles preventing prolapsed of AV valves

Question 14

Fibrous pericardium

Answer 14

tough fibrous outer layer, prevents over distention (over filling), acts as an anchor

Question 15

Serous pericardium and its two layers

Answer 15

thin, transparent, inner layer
1. parietal pericardium
2. visceral pericardium
the two layers are continuous and have a pericardial cavity between them filled with pericardial fluid

Question 16

parietal pericardium

Answer 16

lines the fibrous outer layer

Question 17

Visceral pericardium

Answer 17

covers the hearts surface

Question 18

three layers of heart wall

Answer 18

Epicardium - single squamous epithelium over areolar tissue
Myocardium - middle layer, thickest, composed of cardiac muscle cells for contractibility allowing the heart to create pressure
Endocardium - smooth inner surface of heart chamber covers valve surface and continuous with epithelium

Question 19

pathway of blood through the heart

Answer 19

• Superior and inferior vena cavae.
• Right atrium.
• Tricuspid/atrioventricular valve.
• Attached via chordae tendineae To the papillary muscles.
• Right ventricle.
• Pulmonary/semi-lunar valve.
• Where it becomes the pulmonary circulation.
• Pulmonary trunk/artery.
• Lungs.
• Where blood becomes oxygenated.
• Right and left pulmonary veins.
• Left atrium.
• Where it becomes systemic circulation.
• Bicuspid/mitral/atrioventricular valve.
• Left ventricle.
• Which has a much thicker muscular wall than the right side of the heart.
• Aortic/semi-lunar valve.
• Aorta.
• To the rest of the body and organs.

Question 20

describe how a heartbeat is generated.

Answer 20

through the cardiac cycle
Repetitive contraction (systole) and relaxation (diastole) of heart chambers, moves blood throughout the body

Question 21

pulmonary circulation

Answer 21

deoxygenated blood is transported to lungs for oxygenation and then returned to the heart

Question 22

Systemic circulation

Answer 22

oxygenated blood is transported to body tissues then returned to the heart

Question 23

Coronary circulation

Answer 23

part of systemic circulation that supplies heart only

Question 24

Describe the effects of exercise on cardiac output.

Answer 24

cardiac output increases during exercise
To supply cells which are working with the extra oxygen and nutrients they need and to remove waste
Cardiac output = heart rate x stroke volume
amount of blood ejected from the heart at every contraction

Question 25

List the components of blood.

Answer 25

Plasma
Proteins, water, ions, nutrients, waste products, gases
formed elements
Platelets, white blood cells, red blood cells
Platelets = assist with blood clotting and sealing holes in blood vessels

Question 26

Describe the transport of carbon dioxide and oxygen in the blood.

Answer 26

Erythrocytes
red blood cells
Carries oxygen from lungs to tissues, dissolved in plasma or attached to haemoglobin
Carries carbon dioxide from tissues to lungs in plasma and attached to haemoglobin
Red blood cells have no nucleus and a biconcave shape to increase surface area and increase their oxygen carrying capacity

Question 27

arteries

Answer 27

= away
take blood away from the heart to tissues
Located deep in tissue
Thick walls
No valves
Contain blood under pressure
All are oxygenated except for the pulmonary artery

Question 28

veins

Answer 28

take blood to the heart
Blood not under pressure
Located closer to surface of body
Thinner walls then arteries
Contain valves

Question 29

Capillaries

Answer 29

site of exchange between tissues
three types
1. Continuous = no gaps between endothelial cells, less permeable to large molecules
2. Fenestrated = have pores in endothelial cells called fenestrae, highly permeable
3. Sinusoidal = larger diameter, irregular incomplete wall of endothelial cells

Question 30

Why is the wall in the left ventricle much thicker then the right ventricle

Answer 30

right ventricle only has to push blood to the lungs which is closer whereas the left ventricle has to push blood to the whole body so needs more power in the contraction

Question 31

11. Name the two major arteries that leave the heart and the chamber they exist from

Answer 31

pulmonary trunk = right ventricle
Aorta = left ventricle

Question 32

pulmonary trunk

Answer 32

becomes the two pulmonary arteries (one for each lung)

Question 33

12. What are the names of the major veins entering the heart

Answer 33

superior and inferior vena cave into the right atrium
Pulmonary veins into the left atrium