cardio-respiratory and vascular systems: functions of blood vessels

Question 1

describe the transportation of nutrients around the body

Answer 1

• oxygen is breathed in and held in the alveoli sacs
• capillaries surround the air sacs and allow diffusion of the oxygen into the blood (oxyhaemoglobin) and rmeoval of carbon dioxide to be breathed out
• the oxygenated blood is taken back to the heart via the pulmonary vein
• blood enters the left atrium, then the left ventricle, and is pumped out via the aorta to the body and the wokring muscles
• oxygen is diffused into the working muscles and carbon dioxide passed the other way to be converted into water or breathed out.
• veins carry the deoxygenated back to the heart
• the right atrium then the left ventricle allow blood to be pumped to the lungs to be oxygenated via the pulmonary artery

Question 2

define thermoregulation

Answer 2

the control of temperature within the body

Question 3

how does the body thermoregulate in hot conditions

Answer 3

• if body is too hot, blood is taken closer to the skin, making it appear red.
• as well as losing heat through evaporation of sweat, arteries that run near to the skin vasodilate to allow more blood through.
• this allows bheat to be lost via radiation and convection, heat is lost to the air.

Question 4

how does the body thermoregulate in cold conditions

Answer 4

• if the body is too cold, blood is taken away from the skin
• as well as involuntary shivering to keep you warm, arteries that run near to the skin vasoconstrict so less blood moves through
• this prevents heat loss and ensures blood is supplied to the body’s core and vital organs e.g. lungs and liver