Transport In Animals

Question 1

Artery

Answer 1

• carry blood away from heart under high pressure (have to WITHSTAND pressure + force)
  -thick elastic layer - able to withstand force , enables them to stretch recoil
  Collagen provides structure + support, manintains shape + volume
  Smooth muscle contract + relaxes to change size of lumen/ control blood pressure
  Provides strength to withstand pressure

Question 2

Veins

Answer 2

Carry blood back to heart
Less pressure blood
Thinner elastic layer , valves to prevent backflow, MORW collagen than arteries to give structural support as they carry large volumes of blood

Question 3

Capillaries

Answer 3

Allow substances to be exchanged between blood + surrounding cells.
Walls one cell thick short diffusion distance
Small enough to form network needed to exchange substances , only large enough to allow RBCs to travel through in single file h increase contact of RBCs w capillary wall)

Question 4

Explanation of Bohr effect

Answer 4

Reduces affinity of hb for oxygen
More oxygen released where needed , where carbon dioxide coninc high

Question 5

Why fetal HB has higher affinity for oxygen

Answer 5

Must be able to bind to oxygen in lower partial pressure in placenta when adult HB dissociates from oxygen

Question 6

RBCs disadvantage for having no nucleus

Answer 6

Limited life span 120 days