Transport in animals- blood, tissue fluid and lymph Flashcards
where is plasma found and what are its functions?
plasma is a yellow liquid found in blood. It carries glucose, amino acids, mineral ions, hormones and more. Plasma also transport red blood cells, white blood cells and platelets.
What are the functions of the blood?
-transport oxygen and carbon dioxide
-transport digested food molecules
-transport waste products to excretory organs
-transport hormones
-transport platelets
-contributes to maintenance of a steady body temperatures and minimises pH changes.
why can’t large plasma proteins pass through fenestrations in the capillary walls?
because they are needed for the osmotic effect as they give the blood in the capillaries a high solute potential compared to surrounding liquid. As a result, water has a tendency to move into the blood through osmosis which is called oncotic pressure.
what is hydrostatic pressure?
the pressure from the surge of blood that occurs every time the heart contracts as blood flows through the arterioles into the capillaries.
where is hydrostatic pressure high?and how does it produce tissue fluid?
at the arterial end of the capillaries which is higher than oncotic pressure so plasma is squeezed out the capillaries (leaving proteins) which fills spaces between cells and is called tissue fluid
Describe the composition of tissue fluid. Does diffusion take place?
Tissue fluid has the same composition as plasma without red blood cells and the plasma proteins . Diffusion does take place between the blood and the cells.
As blood moves through the capillaries to the venous system, how does the hydrostatic pressure and oncotic pressure change?
hydrostatic pressure falls causing tissue fluid to move out and the pulse to be lost. The oncotic pressure stays constant and is now stronger than the hydrostatic pressure. By the time blood returns to veins most tissue fluid is back into blood vessels.
what is lymph?
tissue fluid that doesn’t return to capillaries which drains into a system of blind ended tubes called lymph capillaries where it is known as lymph.
Describe the composition of lymph?
similar composition to plasma and tissue fluid but has less oxygen and fear nutrients. It contains fatty acids which are absorbed into the lymph from villi of the small intestine.
what is plasma mostly composed of?
water
how is fluid transported through lymph vessels?
lymph capillaries join to form a larger vessel. Fluid is transported by squeezing of body muscles. Valves are found in the lymph which eventually returns to the blood flowing into the veins.
where are the lymph nodes found?
along the lymph vessels
what are the functions or the lymph nodes?
-lymphocytes build up at the lymph nodes and when necessary produce antibodies which are passed into the blood.
-lymph nodes also intercept bacteria and the debris from the lymph which are ingested by phagocytes which are found in the nodes. The lymphatic system plays major role in the defence mechanisms of the body.
why do doctors often examine neck, armpits and stomach?
They are the site of major lymph nodes. Enlarged lymph nodes are a sign of the body fighting off an invading pathogen.
What happens in the capillaries when tissue fluid is formed?
By removing plasma and leaving the proteins the capillaries have a low water potential causing water to osmose into the capillaries.
