The Heart KA5

Question 1

Where does the heart circulate blood?

Answer 1

Through the arteries, then to the capillaries, then to the veins where blood is returned to the heart

Question 2

As the blood moves away from the heart what happens?

Answer 2

A decrease in blood pressure

Question 3

Blood vessel structures

Answer 3

•Central space= Lumen
•Lined by a layer of cells = called endothelium
•this is surrounded by muscle tissue and connective tissue

•These layers differ in the arteries and veins to suit their function

Question 4

What do arteries do, and what do they have

Answer 4

•Carry blood away from heart

•have an outer layers of connective tissue containing elastic fibres

•they have a thicker middle layers containing smooth muscle with more elastic fibres

Question 5

Capaliries allow what? With what?

Answer 5

•Exchange of substances, with tissue through their thin walls
(Carried in blood .eg glucose, O2)

•have a narrow lumen

Question 6

Veins do what?
They have what?

Answer 6

•Carry blood back to the heart
•have an outer layer of connective tissue containing elastic fibres

Question 7

Vein muscle tissue?

Answer 7

•much thinner muscular walls than arteries
•They contain valves which prevent back flow of blood

Question 8

Capaliries bed

So what happens to blood

Answer 8

•Blood arriving at the artery side of a capillary bed is at a much higher pressure than blood in the capaliries.

•So blood if forced into these narrow capillaries

Question 9

Blood forces does what occurring a process

Answer 9

As blood is forced into the narrow capillaries it undergoes pressure filtration

Question 10

What does pressure filtration cause ?
(Plasma)

Answer 10

Plasma to pass through capaliries walls into the tissue fluid

Question 11

What does tissue fluid supply?
By what process

Answer 11

•Supplies cells with glucose, oxygen and other substances (by diffusion)

Question 12

The wastes?

What about the tissue fluid?

Answer 12

•CO2 and other wastes diffuse out the cells into the tissue fluid, eventually exerting the body.

•much of the tissue fluid returns to the blood (into capillaries by osmosis)

Question 13

Differences between tissue fluid and plasma

Answer 13

•They are similar in composition
Except plasma proteins

•which are too large to be filtered through capillary walls

Question 14

Lymph and their vessels?

Answer 14

•Excess tissue fluid which doesn’t return to the blood is called lymph

•Lymph is absorbed by lymphatic vessels & returned to the circulatory system.