parts of a nephron in order
glomerulus, (technically no)
Bowman’s capsule
proximal tubule
descending loop of Henle
ascending loop of Henle
distal tubule
collecting duct
three steps to form urine
- filtration
- reabsorption
- secretion
where does urea come from
is produced by the liver to eliminate ammonia
filtration
dissolved solutes pass through the glomerulus into the Bowman’s Capsule (filtration based on size)
reabsorption
throughout the nephron, all useful/ required materials (such as salt and water) are reabsorbed into the body
reabsorption happens how
through passive and active transport
secretion
few waste products left int he efferent arteriole can get secreted into the nephron at the distal tubule
how is uric acid made?
formed from the breakdown of nucleic acids
ADH abbreviation
Antidiuretic hormone
what does ADH help regulate
blood OSMOTIC pressure
Process of ADH
- osmoreceptors in the hypothalamus shrink due to loss of water
- hypothalamus sends message to pituitary gland to release ADH
- ADH allows for water to be reabsorbed by making the tubule membranes for permeable
- released water enters circulation and makes the blood less thick
alternative function to adjust blood osmotic pressure
osmoreceptors in the hypothalamus can send a behavioral signal to make you thristy
Regulating blood pressure and blood volume (in response to injury/blood loss): the pressure detector
juxtaglomerular apparatus
Process of regulating blood pressure/volume
- juxtaglomerular apparatus detects low blood pressure or volume (dehydration or blood loss)
- specialized cells in the apparatus make renin
- renin combines with angiotensinogen (which is already in the blood) to make angiotensin
what is the pathway of angiotensin (adrenal gland)
- angiotensin can stimulate aldosterone from the adrenal gland
- aldosterone is carried to the kidney through the blood
- acts on nephrons to increase Na and H2O reabsorption (H2O helps increase blood volume/pressure
what is the pathway of angiotensin (direct path)
angiotensin can cause constriction of blood vessels (narrow the tubes to increase blood pressure)
impact of alchohol on ADH
ethanol inhibits ADH
so, any remaining water in your body will be peed out, resulting in headaches + other symptoms
why do urea and ammonia levels generally increase after filtration
its not that it increases, its that the concentration increases
- after filtration, water is reabsorbed back into the body at the descending loop of Henle. Thus, the [urea + ammonia] will increase
