Heart and blood

Question 1

What are platelets?

Answer 1

Cell fragments that produce a network of fibres that stops the cell from flowing out and plugs a hole when you have a cut. This forms a blood clot that stops the bleeding

Question 2

Info on arteries

Answer 2

function- leads blood away from heart. Carries blood at systolic pressure(120mHg)
Oxygenated blood
size- lumen diameter= fairly large( rbc flow but closely packed together)
Structure- walls are very thick and contain 4 layer: epithelium, muscle layer,& collagen shell
contains no valves
walls contain thick muscle layer to cope with v high internal pressure

Question 3

info capillaries

Answer 3

function:
not connected to heart
gas exchange 
diffusion carries blood at low pressure
oxygenated + deoxygenated blood
structure:
Lumen diameter= small-1 rbc pass at a time
1 cell thick(of  epithelium tissue)
wall bursts under pressure change
no valves

Question 4

veins info

Answer 4

Function:
Leads towards heart
Carries blood at a very low pressure
deoxygenated blood
lumen diameter very large-many rbc flow at once
Structure:
Walls are thin and contain 3 layers of tissue- epithelium, muscle and elastic tissue and collagen cell
wall thin( muscle tissue thin too) because pressure is low
contains valves to prevent backflow

Question 5

Which is the only artery that does NOT carry oxygenated blood?

Answer 5

pulmonary artery

Question 6

what do veins do?

Answer 6

transport blood to the heart

Question 7

what is the heart?

Answer 7

The heart is the muscular organ that pumps blood around the body.

Question 8

The heart receives oxygenated blood from the lungs through which blood vessel?

Answer 8

pulmonary vein

Question 9

adaptations of capillaries

Answer 9

1 cell thick = short diffusion pathway

Question 10

what are the adaptations of alveoli?

Answer 10

•1 cell thick = short diffusion pathway
Large surface area = large volume of O2
•Moist walls allows gases to dissolve to help them cross the gas exchange pathway
•Permeable walls allows gases to pass through
•large diffusion gradient- higher conc of o2 in alveoli than in blood = diffuse faster
•Alveoli are surrounded by a network of capillaries. This means that:
Alveoli have a rich blood supply.
The distance that gases need to diffuse across is small.( short diffusion pathway)

Question 11

do platelets have nucleus?

Answer 11

no