26 The Heart

Question 1

Two types of blood systems

Answer 1

Open (crabs lobsters spiders snails)
Closed (humans)

Question 2

Open blood system

Answer 2

The heart pumps blood into open ended vessels so then the blood leaves the blood vessel and moves around the cells in the animals body, then back into the blood vessels

Question 3

Closed blood system

Answer 3

The blood remains in a continuous system of blood vessels
Materials are exchanged through thin walls of the smallest vessels

Question 4

Why is a closed blood system more efficient than an open blood system

Answer 4

Blood can be pumped around the body faster- this moves nutirents, oxygen around faster which allows animal to be more active
Flow of blood to diff organisms can be increased/decreased
Eg. More blood can be supplied to legs when animal is running

Question 5

Composition of human closed blood system

Answer 5

Blood
Heart
Blood vessels

Question 6

3 main types of blood vessle

Answer 6

Arteries- carry blood away from heart
Veins- carry blood to heart
Capillaries- tiny vessels that link arteries and veins

Question 7

Arteries

Answer 7

Carry blood away drom heart
Blood under high pressure
Thick strong wAlls
Small lumen
No valves

Question 8

Veins

Answer 8

Carry blood to heart
Blood under low pressure
Thin weaker walls
Large lumen
Have valves

Question 9

Structure of arteries and veins

Answer 9

Outer layer of protein called collagen prevents vessel from expanding too much
Middle layer of muscle and elastic fibre alters size of vessle
Endothelium is a thin layer of cells that surrounds the lumen

Question 10

What is blood pressure

Answer 10

Force the blood exerts against the wall of a blood vessel

Question 11

What do valves do

Answer 11

They control the direction of blood flow by not letting blood go backwards

Question 12

Capillaries

Answer 12

Tiny much branched blood vessels.
Very thin walls made of a single layer of endothelium cells
Capillaries allow exchange of materials as they are porous

Question 13

The heart is located

Answer 13

Between the two lungs pointing slightly to the left hand side of the chest and just above the diaphragm

Question 14

Whats the heart made of

Answer 14

Cardiac muscle ans is surrounded by a double membrane called the pericardium

Question 15

What do atria do

Answer 15

Theyre the upper chambers of the heart and they pump blood to the lower chambers (ventricles)
They have thin walls because they pump blood a short distance

Question 16

What do ventricles do

Answer 16

They pump blood out of the heart

Question 17

Where does the right ventricle pump blood to

Answer 17

The lungs

Question 18

Where does the left ventricle pump blood to

Answer 18

Head and body
This is a longer distance than other ventricle so it has a thicker wall

Question 19

How are the valves in the heart held in place

Answer 19

Theyre held in place by tough cords called tendons
The tendons are attached to the walls of the heart by small projecting muscles

Question 20

Valve on the left hand side of the heart is called

Answer 20

Biscupid valve
(Two flaps)

Question 21

What are the valves on the right side of the heart called

Answer 21

Triscupid
(Theee flaps)

Question 22

Where are semilunar valves located

Answer 22

Top of the heart exit of pulmonary artery and vein

Question 23

LORD

Answer 23

Left oxygenated
Right deoxygenated

Question 24

Where does deoxygenated blood enter the heart

Answer 24

Enters the right atrium through the vena cava

Question 25

Where does oxygenated blood enter the heatt

Answer 25

Enters left atrium through the pulmonary veins

Question 26

Advantages of double cirxulation

Answer 26

Oxygen rich and oxygen poor blood are separate
Blood pressure is high enough to reavh all parts of tje body

Question 27

Pulmonary circuit

Answer 27

Heart lungs heart

Question 28

Systemic circuit

Answer 28

Heart body heart

Question 29

Whats a portal system

Answer 29

Blood pathway that begins and ends in capillaries