Structure of the heart

Question 1

Why don’t we just have oxygen diffusing through our body instead of having a cardiovascular system

Answer 1

Would be too slow

Lots of cells wouldn’t be able to be sustained

Would limit size of organism

Question 2

Advantages of circulatory system

Answer 2

Organisms can be bigger

Can sustain a higher metabolic rate

Direct flow of substances between organs

Blood flow can regulate organ function

Question 3

Drawbacks of a circulatory system

Answer 3

Circulatory failure can be fatal

High pressure and flow require control

High pressures place stress on vessels

Metabolically expensive

Question 4

Functions of circulatory system

Answer 4

Transport to tissues

Remove waste products from tissues

Transport blood cells around the body

Regulate body temperature by transfer of heat

Question 5

Things the circulation of blood transports

Answer 5

Oxygen

Nutrients

Hormomes

Growth factors

Question 6

Cardiac output at rest

Answer 6

About 5L.min^-1

Question 7

Cardiac output during exercise

Answer 7

About 2-35L.min^-1

Question 8

Location of heart

Answer 8

Question 9

Pericardium

Answer 9

Lining of the pericardial cavity

Question 10

Pericardial cavity

Answer 10

Contains pericardial fluid

Acts as a lubricant, reducing friction as the heart beats

Question 11

Visceral pericardium

Answer 11

Covers outer surface of the heart

Inner most layer of pericardium

Question 12

Parietal pericardium

Answer 12

Lines inner surface (heart side) of the fibrous pericardium

Question 13

Fibrous pericardium

Answer 13

Surrounds the heart

Dense network of collagen fibres

Stabilses the position of the heart in the mediastinum

Question 14

What is the serous pericardium made up of

Answer 14

Visceral pericardium

Parietal pericardium

Question 15

Order of pericardium starting closest to the heart

Answer 15

Visceral pericardium

Parietal pericardium

Fibrous pericardium

Question 16

Another name for the fibrous pericardium

Answer 16

Pericardial sac

Question 17

Right atrioventricular valve

Answer 17

Tricupsid valve

Seperates right atrium and the right ventricle

Has 3 fibrous flaps or cusps

Question 18

Which valve in the heart doesn’t have 3 fibrous flaps

Answer 18

Left atrioventricular / bicuspid / mitral valve

Question 19

Chordae tendinae

Answer 19

Tendinous connective tissue fibres

Attached to the free edges of the cusps in the valves of the heart

Stops the AV valves swinging loose and letting blood flow backwards

Originates from the papillary muscles

Question 20

Which valve seperates the right ventricle and the pulmonary trunk

Answer 20

Pulmonary valve

Question 21

Pulmonary valve

Answer 21

After right ventricle

Made of 3 semilunar cusps made of thick connective tissue

Stops blood flowing back into the right ventricle as it relaxes

Question 22

Pupillary muscles

Answer 22

Conical muscular projections

Arise from the inner surface of the right ventricle

Where cordae tendinae originate

Question 23

Which valve seperates the left atrium and left ventricle

Answer 23

Left AV / bicuspid valve / mitral valve

Question 24

Left AV valve

Answer 24

Bicuspid / mitral valve

Has 2 cusps/fibrous flaps

Seperates left atrium and left ventricle

Question 25

Aortic valve

Answer 25

Valve that blood passes through to leave left ventricle 3 semilunar cusps

Question 26

Flow of blood from body into the heart and up to the lungs

Answer 26

1. Superior/inferior vena cava 2. Right atrium 3. Trucuspid valve 4. Right ventricle 5. Pulmonary semilunar valves 6. Pulmonary trunk 7. Pulmonary arteries

Question 27

Flow of blood from lungs, through heart and to the body

Answer 27

1. Pulmonary veins 2. Left atrium 3. Bicuspid valve 4. Left ventricle 5. Aortic semilunar valve 6. Aorta

Question 28

Difference between right and left ventricles

Answer 28

Left ventricle wall is thicker Left ventricle is spherical Right ventricle resembles a pouch attached to the wall of the left ventricle

Question 29

Which ventricle has the thicker wall Why

Answer 29

Left Requires more force to pump the blood around the body

Question 30

Circuits of the circulatory system

Answer 30

Pulmonary Systemic

Question 31

Pulmonary system

Answer 31

Carries blood to the lungs

Question 32

Systemic circuit

Answer 32

Carries blood to the rest of the body Everything but lungs

Question 33

What moves blood along

Answer 33

Elastic rebound Blood pressure

Question 34

Elastic rebound

Answer 34

Aorta is stretched by the blood pumped from the left ventricle When the left ventricle relaxes no more blood is flows into the aorta The pressure in the aorta declines Walls of aorta recoil This pushes the blood along

Question 35

How does blood enter the coranary ateries

Answer 35

They originate from the base of the aorta When the aorta recoils and pushes blood along some goes backwards and into the coranary arteries through the aortic sinus

Question 36

Cardiac muscle cell

Answer 36

Wrapped in strong and flexible elastic sheath Adjacent cells are tied together by fibrous cross links (struts) These fibres are woven into sheets that seperate superficial and deep muscle layers

Question 37

# Cardiac muscle cells Connective-tissue fibres roles

Answer 37

Provide physical support for cardiac muscle fibres, blood vessels and nerves of the myocardium Help distribute the forces of contraction Add strength and prevent over-expansion of heart Provide elasticity and helps return the heart to it's original size and shape after contraction

Question 38

Myocardial infarction

Answer 38

Coranary circulation becomes blocked Cardiac muscle cells affected die from lack of oxygen Tissues degenerate and leads to a non-functional area (infarct)

Question 39

Three layers of heart wall

Answer 39

Epicardium Myocardium Endocardium

Question 40

Epicardium

Answer 40

Layer of heart wall Is the visceral pericardium Composed of exposed mesothelium and an underlying layer of loose connective tissue attached to the myocardium

Question 41

Myocardium

Answer 41

Layer of heart wall Muscular wall of heart

Question 42

What does the myocardium consist of

Answer 42

Cardiac muscles Blood vessesls Nerves

Question 43

Endocardium

Answer 43

Layer of heart Covers the inner surfaces of the heart Just a simple squamous epithelium

Question 44

Features of cardiac muscle

Answer 44

Striated muscle Branches cells One or two nuclei in middle of cell Intercalated discs