8.3 Blood, Tissue Fluid & Lymph Flashcards
Why does tissue fluid have a similar composition to blood?
Formed out of components of blood
which are forced out of the capillary along with plasma
due to hydrostatic pressure.
What does the blood carry?
Glucose, Amino acids, Mineral ions, Hormones,
Plasma proteins, Red blood cells, White blood cells,
Platelets
What 3 plasma proteins does the blood carry?
ALBUMIN - maintains ψ
FIBRINOGEN - involved in blood clotting
GLOBULINS - transport + immune system
What is tissue fluid?
SOLUTION surrounding cells of multicellular animals
SAME COMPOSITION as blood but without RBCs + large plasma proteins
What are gaps in the endothelium called?
fenestrations
What are the functions of the blood?
Transport of…
O2 + CO2 to and from respiring cells
DIGESTED molecules from small intestine
NITROGENOUS WASTE ⟶ excretory organs
HORMONES: site of production ⟶ action
PLATELETS ⟶ damaged tissue
CELLS + ANTIBODIES
What are the OTHER functions of the blood? (not transport)
maintains pH by acting as BUFFER
maintains TEMPERATURE (distributes heat using plasma)
What happens at the ARTERIAL END of the capillaries?
hydrostatic pressure > oncotic pressure
so water/plasma moves out of vessel by OSMOSIS
carries SOLUTES from blood with it, which move by MASS FLOW out of FENESTRATIONS
less water now remains in blood vessel, so hydrostatic pressure ￬
What happens after tissue fluid is formed?
BATHES cells
DIFFUSION between cells + tissue fluid
What happens at the VENOUS END of the capillary?
oncotic pressure > hydrostatic pressure
so ≈ 90% tissue fluid REABSORBED into capillary by OSMOSIS
carries WASTE substances with it
What is HYDROSTATIC PRESSURE?
pressure created by WATER in an ENCLOSED SYSTEM
always positive
What is ONCOTIC PRESSURE?
tendency of H2O to move INTO BLOOD
by OSMOSIS
due to lower ψ created by plasma proteins
(approx -3.3kPa)
What is the relative magnitude of forces in the arterial end?
hydrostatic pressure > oncotic pressure
in terms of magnitude
What is the relative magnitude of forces in the venous end?
oncotic pressure > hydrostatic pressure
in terms of magnitude
What is lymph?
MODIFIED tissue fluid
COLLECTED in the LYMPH system
(tissue fluid which is not reabsorbed after exchange with cells)
How is lymph returned into the bloodstream?
remaining tissue fluid DRAINS into blind-ended LYMPHATIC CAPILLARIES
formation of LYMPH
moved along vessel by surrounding MUSCLE CONTRACTIONS + help from VALVES
LYMPHOCYTES build up at LYMPH NODES - produce ANTIBODIES
(during infection, lymphocytes multiply @ lymph nodes)
lymph reenters blood in left + right SUBCLAVIAN VEINS
What is a blind-ended vessel?
a vessel which is open at one end and closed in the other
What is the difference in composition of tissue fluid + lymph?
lymph contains LESS NUTRIENTS - since diffused into cell during exchange
lymph contains MORE FATTY ACIDS -
Lymph capillaries converge to make larger vessels. How is this larger vessel similar to veins?
contains VALVES
fluid is moved through vessel by MUSCLE CONTRACTIONS
What happens at the lymph nodes during an infection?
accumulated lymphocytes multiply
How do lymph nodes protect the body from pathogens?
LYMPHOCYTES accumulate, multiply + produce more antibodies
which INTERCEPT bacteria in lymph, preventing them from reabsorbing into blood
In what BLOOD vessel does the lymph drain into?
right/left subclavian veins
What are the solutes found in blood but not in tissue fluid?
erythrocytes, large plasma proteins
Why are red blood cells and large plasma proteins not found in tissue fluid?
TOO BIG to pass through FENESTRATIONS in endothelium
Though red blood cells are not found in tissue fluid, ___ is.
oxygen
approximately how much tissue fluid which is formed drains back into the blood?
90%
What is the relative composition of components in the blood?
55% plasma
45% RBC, WBC, platelets,
