Biology - Chapter 9 (Transport in Humans)

What is the artery blood direction?

carry blood away from heart

What are the adaptations of artery walls?

It has a thicker wall to withstand high blood pressure and prevent rupture, has more muscles on wall to dilate or narrow down lumen in order to regulate blood pressure, has more elastic tissues on wall to allow recoil of artery which pushes blood forward when heart relaxes

What are the adaptations of veins?

It has a thinner wall, but contains larger lumens to reduce the resistance for blood flow, and valves to prevent backflow of blood

What is the force of blood flow in arteries?

pumping force of the heart

What is the force of blood flow in veins?

the contraction of skeletal muscle

Why is the blood pressure higher in arteries?

They pump blood directly from the heart

What blood vessels carry lumen and what are their sizes?

arteries have a smaller lumen than veins

Which specific blood vessel do not have valves, why?

Pulmonary veins, as the distance from lung to heart is very short, the pressure by heart contraction is strong enough to keep blood from going to the left atrium.

What are some adaptation of capillaries for their function?

Their network of capillaries provide a large surface area to allow rapid exchange of materials between blood and body cells by diffusion, the cross-sectional area of capillaries is very large to slow down blood flow and allows a longer period of time for complete exchange of materials, its walls are one-cell thick to provide a shorter distance for rapid exchange of materials

In capillaries specifically, what other than red blood cells can move around?

phagocytes, a kind of white blood cell

What is the fluid in blood and what does it contain?

plasma, 90% water with some antibodies, urea for excretion, gases, hormones

What is the shape of red blood cells?

biconcave disc

What is the function of white blood cells?

protect against disease by killing pathogens

What is the function of blood platelets?

help in blood clotting to stop bleeding and prevent entry of pathogens

Where are red blood cells and blood platelets destructed?

liver and spleen

What is the lifespan of red blood cells?

about 120 days

What blood cell has nucleus, and how are they shaped?

White blood cells, phagocytes have them lobed while lymphocytes round and large

What are the capillary wall’s adaptation?

it has a one-cell thick endothelium to reduce diffusion distance for a quicker exchange of materials, they are highly-branched to slowdown speed of blood flow and allow more time to complete material exchange.