internal transport

Question 1

how is the structure of the heart adapted to carry out its function

Answer 1

divided in to a right and left side by septum
left ventricle is thicker than right since it pumps blood to the whole body
valves to ensure one way flow of blood and prevent its backflow
walls of atria are thin so they can be stretched to receive blood and contract with enough force to push blood through tricuspid and bicuspid valve in to ventricles
walls of heart are made of cardiac muscle
cardiac ms has its own blood supply from coronary arteries to supply with O2 and nutrients

Question 2

describe the structure of the cardiac muscle under a light microscope

Answer 2

branching cells which are ms fibres which forms mesh like frame work
cells are straited with several nuclei

Question 3

explain why heart rate changes during exercise

Answer 3

changes in heart rate are controlled by nerve impulses sent from the cardiac centre in medulla
ms produce more CO2 during aerobic respiration
this change is detected by receptors in aorta and carotid artery
nerve impulses are sent through sensory nerve to the medulla
medulla sends nerve impulses through accelerator nerve
heart rate inc
when CO2 returns to normal medulla sends nerve impulses through decelerator nerve

Question 4

how are arteries adapted to carry out its function

Answer 4

thick wall with ms fibres and elastic tissue to withstand high blood pressure and stretch and recoil
small lumen to maintain high blood pressure

Question 5

how are veins adapted to carry out their function

Answer 5

thin wall with little muscle and elastic tissue
wide lumen
semi lunar valves to ensure one way flow and prevent back flow

Question 6

what is the function of tissue fluid

Answer 6

forms pathway for diffusion of substances between capillaries and cells

Question 7

how RBCs adapted to carry out their function

Answer 7

contain Hb to bind with O2
no nucleus to carry more Hb
biconcave shape for larger surface area
flexible so can squeeze through capillaries

Question 8

what does enzyme thrombin do

Answer 8

changes soluble fibrinogen to insoluble fibrin

Question 9

describe how antibodies are made

Answer 9

mouse is injected with foreign antigen to produce lymphocytes which are collected from spleen
mouse lymphocytes are fused with cancer cells to form hybridoma cells
culture conditions allow hybridoma cells to grow
individual hybridoma cells are isolated and grown
monoclonal antibodies are produced

Question 10

describe how MCA can detect cancer cells

Answer 10

made using antigens of cancer cells

labelled using either coloured dye or radioactively