Kidneys & body Fluid Flashcards
What is the body water % of male, female & neonate?
Adult male 60%
Adult female 50%
Neonate 75%
Define what water is & what does it do?
Universal solvent
Gives volume & turgor (pressure) to cells (intracellular fluid)
Vital component of blood & the fluid between cells (interstitial fluid)
Maintains whole body regulation
What body compartment holds the most fluid?
Intracellular fluid (28 ltrs)
What body compartment holds the least fluid?
Transcellular fluid (0.8ltrs)
What are the 4 types of fluid compartments?
Intracellular, transcellular, Interstial, blood plasma
What compartment holds more fluid? Interstitial/ blood plasma
Interstial (10.4 ltrs)
Blood plasma ( 2.8 ltrs)
How does water move between fluid compartments?
Osmosis
What is the rule to maintain fluid balance?
To maintain fluid balance, fluids in must be equal to fluids out.
Cellular metabolism makes some of the bodies water. How?
O2 + glucose = energy + CO2 + H2O
How is fluid balance achieved?
Balance between fluid intake (thirst) and urine output.
What triggers thirst?
Body fluids become too concentrated.
What receptors measure fluid levels?
Osmoreceptors
Where are osmoreceptors located?
Hypothalmus
Where is the integrator for fluid balance located?
Hypothalmus
What does the hypothalamic integrator regulate?
Water intake via thirst mechanism.
What regulates water loss via urine?
Kidneys
What are the kidneys responsible for?
Elimination of water- soluble waste materials
Fluid volume regulation
Electrolyte balance
Plasma pH regulation
What is the functional unit of the kidney?
Nephron
How many nephrons does each kidney contain?
Around 1 million (tiny tubular structures)
What is the job of the nephron?
Form urine of the appropriate volume & composition.
To ensure fluid balance.
To maintain plasma electrolyte & pH levels within normal range.
What are the 3 processes involved in urine formation?
Glomerular filtration
Selective reabsorption
Tubular secretion
What is glomerular filtration?
Forms a filtrate of plasma.
What is selective reabsorption?
Process by which substances may be absorbed from the filtrate back into the peritubular blood.
What is tubular secretion?
Process by which substances may be added to the filtrate from the peritubular blood.
Where does glomerular filtration take place?
Bowman’s capsule
When does filtration take place within bowman’s capsule?
As blood flows through the glomerular tuft.
What part of bowman’s capsule has tiny gaps between the cell making them leaky?
Capillary membrane & membrane lining
What is the function of the capillary membrane & membrane lining (double sac)?
Allows solutes and water to pass through but restraining larger substances.
What substances are filtered & enter bowman’s space?
Water Electrolytes Glucose Amino acids Urea Small metabolic waste molecules
What substances are too big to be filtered by bowman’s capsule?
Blood cells
Plasma proteins
Large metabolic waste molecules
What is the name of the fluid that enters bowman’s capsule as a result of filtration?
Glomerular filtrate
Glomerular filtrate is formed at what rate?
Around 120 mls/min (glomerular filtration rate)
What % of blood passes through the glomerular capillaries & undergoes filtration?
20%
What is the filtration fraction?
% of blood that passes through the glomerular capillaries & undergoes filtration. (20%)
