circulatory system

Question 1

features of arteries:

Answer 1

-carry blood to the heart to the rest of body
-walls are thick and muscular and have elastic tissue to stretch and recoil as heart beats , maintains high BP
- inner lining (endothelium is folded) allowing artery to stretch

Question 2

features of veins:

Answer 2

• take blood back to the heart under low pressure
  -wider lumen, with very little elastic or muscle tissue
  -contains valves to stop blood flowing backwards
  -

Question 3

features of capillaries which adapts them for gas exchange:

Answer 3

-found near cells in exchange system so theres a short diffusion pathway
-walls are one cell thick, which shortens diffusion pathway
-large number of capillaries, to increase surface area for exchange
networks of capillaries are called capillary beds

Question 4

how tissue fluid formed?

Answer 4

-Hydrostatic pressure is created when blood is pumped along the arteries, into arterioles and
then capillaries. This pressure forces blood fluid out of the capillaries. The fluid is referred to as tissue fluid.

Question 5

how is tissue fluid removed from the body?

Answer 5

The remaining tissue fluid which is not pushed back into the capillaries is carried back via the
lymphatic system. The lymphatic system contains lymph fluid. However, lymph fluid contains less oxygen and nutrients compared to tissue fluid. The lymph system also contains lymph nodes which
filter out bacteria and foreign material from the fluid with the help of lymphocytes which
destroy pathogens as part of the immune system defences.

Question 6

what is tissue fluid?

Answer 6

Tissue fluid is a liquid containing dissolved oxygen and nutrients which serves as a means of
supplying the tissues with the essential solutes in exchange for waste products such as carbon
dioxide.