Homeostasis Flashcards
Homeostasis
a process by which a constant internal environment is maintained despite changes to the external environment
Monitor
note receptor changes
Coordinating Center
interprets monitor to put regulator into action, creator of a preset condition
Regulator
effects bodily parts to return to the preset condition
Urinary System (Renal System)
to eliminate waste, control blood volume, and regulate blood pressure
key parts of the urinary system
kidney bladder urinary sphincter ureter urethra nephron
when sphincter relaxes…
you pee
kidney quantity and size
2, size of fist
kidneys hold what percentage of blood
25% together at any given time
Filter per day, per minute
Kidneys filter 200L of blood per day, 120ml per minute giving 119ml back
urine formation steps
- Filter 2. Reabsorption 3. Secretion
What is filtration
Movement of fluids from blood to nephron. Each nephron has its own capillary supply.
How does filtration work?
dissolved solutes pass from walls of glomerulus into Bowman’s capsule.
H2O, NaCl, glucose, amino acids, h+ ions pass through
RBC, WBC, platelets, and plasma proteins don’t pass through.
filtration amount per minute
600mL pass through every minute, 20% is filtered out
What does the nephron do in filtration
The nephron works to give the 119mL back by using passive, and active transport to create osmotic gradients which makes water move in the desired direction
Bowmans Capsule
under high-pressure waste is forced from the glomerulus into the capsule, where RBC, WBC, platelets and plasma proteins are filtered out.
Descending loop of henle
permable to salt via active transport, if large amounts of salt remain more water is returned through aquaporins
1st part of ascending loop of Henle
Salts leave via active transport
2nd part of ascending loop of Henle
Waste is less concentrated so access Na+, H+, K+ must be removed through active transport
Proximal Tubule
Have multiple mitochondria, and actively transport Na+ ions out, Cl-, and HCO3 will follow. moving salts will also move h2O through.
75-80% of water lost infiltration is returned to…
The end of the proximal tubule
Water Balance
ADH regulates osmotic pressure of body fluids and blood volume, Aldosterone regulates body fluid volume. These work together via negative feedback. Osmotic receptors shrink when body fluids are low, this sends a signal to the pituitary gland, which releases ADH to travel to the distal tubule.
Blood Pressure Regulation
juxtaglomerular apparatus detects blood pressure, blood pressure turns the apparatus on and releases renin into the blood stream, once entered it changes to anstinogen, anstinogen constricts blood vessels and increases aldosterone from the adrenal gland. Aldosterone causes the nephron to increase Na absorption at the distal tubule.
Pituitary Gland
Master gland that is attached to the hypothalamus, composed of an anterior an posterior lobe
