Trabsport in Animals

Question 1

Capillaries?

Answer 1

• their cell wall consists of only endothelium and are one cell thick
• some capillaries have pores in their walls
• capillaries they permable to water, dissolved substances, urea, O2/CO2
• thin capillary walls they allow more efficient exchange of materials and gases as there’s a shorter diffusion pathway and larger cross sectional area
• they have narrow lumen, restrict blood flow
• the blood O2 concentration varies before/after exchange

Question 2

Function of tendinous chords?

Answer 2

• the papillary muscles contract and creates tension as the tendinous chords they pull on valves to stop it from inverting

Question 3

Functions of main vessels of heart?

Answer 3

• aorta : large artery that transports oxygenated blood from left ventricle to the body
• vena cavae : large veins that transports oxygenated blood from the right atrium from the body
• pulmonary arteries : carry deoxygenated blood from right ventricles to lungs
• pulmonary vein : carry oxygenated blood from lungs to left atrium
• conary arteries : supply heart muscle tissue with O2/nutrients
• conary veins: return deoxygenated blood from heart muscle to vena cavae

Question 4

Arterioles?

Answer 4

• they adjust their diameter to vary the blood supply to a capillary bed

Question 5

Veins?

Answer 5

• have wider diameter lumens and thinner walls than arteries as pressure and flow is lower
• thin muscle layer in walls = easily compressed allowing contracting skeletal muscle to squeeze veins and push blood along

• valves in vein ensure blood flows in one direction - towards heart

Question 6

AV valves

Answer 6

• atrio ventricular valves open when the pressure of blood in atria is greater then in the ventricles: close when the pressure of the blood in the ventricles is greater then in the atria