Formation of tissue fluid from plasma Flashcards
What are the 3 fluid types?
blood, lymph, tissue fluid
What is the difference between blood, tissue fluid, and lymph?
blood forms tissue fluid, tissue fluid forms lymph
What makes up blood? with percentages
plasma (55%), blood cells (45%)
What types of blood cells are in blood?
red blood cells, white blood cells, platelets
What is the function and composition of plasma?
-main component of blood
-90% water, 10% ions, proteins, nutrients, wastes, dissolved gases
What is the function and composition of RBCs?
-carry oxygen and carbon dioxide
-take up O2 in lungs and circulate body, releasing oxygen and removing CO2
What is the function and composition of platelets?
-responsible for blood clotting
-cell fragments formed when large cells break into pieces, form a sticky plug
What is the function and composition of WBCs?
-part of immune system and function in immune response
-2 groups: granulocytes and agranulocytes, all have specific roles
What is tissue fluid?
the liquid that surrounds cells in tissues, allowing for transport between the blood and cells
Where does this fluid come from?
fluid moving out of the capillaries forms tissue fluid
What are some of the substances that make up tissue fluid?
-substances that leave blood plasma
-eg. oxygen, water, nutrients
What is the interaction between tissue fluid and cells?
-transport occurs via diffusion via capillary walls
-cells take in oxygen and nutrients from tissue fluid and release metabolic waste into it
What is the ‘capillary bed’?
network of capillaries in an area of tissue, substances move out of it and into tissue fluid
Name of process by which substances move out of capillaries and into tissue fluid
pressure filtration
What unit is pressure measured in?
kPa
Definition of hydrostatic pressure
fluid pressure exerted by blood on the walls of a blood vessel
What is the main source of hydrostatic pressure?
-heart contractions
-pressure exerted by blood as it moves through blood vessels
What does hydrostatic pressure do?
forces fluid out of the capillaries, through pores in their walls as there is greater pressure inside the capillaries than in the tissue fluid
What are some things that move outward with the fluid?
oxygen, water, nutrients
What are some things that don’t move outward with the fluid?
red blood cells, big proteins
Definition of oncotic pressure
pressure generated by plasma proteins in capillaries, which lowers water potential
Why is the blood within the capillaries of a more negative water potential than the fluid outside?
-fluid loss from capillaries
-oncotic pressure lowers water potential
What is the result of oncotic pressure?
water moves down the water potental and back into the capillary
How do you calculate the net figure?
subtract oncotic pressure from hydrostatic