3.4.1.4: Tissue fluid formation Flashcards
state 3 functions of the blood
immunological function
thermoregulation
maintaining pH of body fluids
what are the 2 main components in the blood and how much of each is in the blood
45% - blood cells
55% - blood plasma
what consists of the blood cells in the blood
erythrocytes (RBCs) - transport oxygen
leukocytes (WBCs) - immunity
thrombocytes - blood clotting
what consists of the blood plasma in the blood
water, proteins, ions, nutrients (glucose, amino acids), water (urea), hormones (insulin, oestrogen), gases (oxygen and CO2)
state and describe 4 features of erythrocytes that are beneficial to the body
squamous biconcave shape - increased surface area:vol for increased efficiency of oxygen exchange
no nucleus/organelles - max. space for Hb, so oxygen transport
diameter is greater than that of capillary, so RBC must squeeze through, short diffusion pathway, slow rate of flow allows more time for gas exchange
High conc. of Hb - transports oxygen
What is tissue fluid
fluid that is between the cells - only in animal tissue
explain the process of how tissue fluid is formed and what happens to tissue fluid when it is formed
high hydrostatic pressure at the arterial end created by left ventricular systole, maintained by elastic recoil. Ultrafiltration occurs here which is where everything leaves the capillaries except for large plasma proteins and blood cells (prevented by basement membrane), water goes into capillary as the water potential in capillaries is low. Cells take in the amino acids, glucose ions, water and gases that were ultra filtered from the blood. At venous end, there is low hydrostatic pressure as lost of blood plasma was lost by ultrafiltration at arterial end, carbon dioxide, urea, and water goes into blood. 99% of the fluid that leaves the blood from ultrafiltration returns via the lymph vessel, which takes in excess tissue fluid making lymph, so it can be removed, if it were left, swelling would occur.
why is it important that the lymph vessel takes in excess tissue fluid
makes lymph from the excess tissue fluid, so it can be removed, as if it were left, swelling would occur
How does the osmotic and hydrostatic pressure change along the capillary bed
at the arterial end, hydrostatic pressure is higher than osmotic pressure, this is where ultrafiltration occurs resulting in the hydrostatic pressure being lower than the osmotic pressure at the venous end, where absorption of fluid, gases and water occurs
what 3 ideas provide unidirectional flow of lymph and so makes sure the lymph doesn’t backflow and returns to blood via thoracic duct, subclavian vein
single layer of overlapping epithelial cells, valves, blind-ended
what is the significance of the single layer of overlapping epithelial cells in the lymph vessel
excess tissue fluid weight presses down on overlapping cells creating pores
