excretory sys— urine

urinary system

Liquid waste removed from the urinary tract

Function of the urinary sys

Eliminate waste, balance ph and balance water

Nephron

In the kidney, the structure that filters the blood.

First process in the nephron

Filtration of blood

second process in the nephron

Re-absorption of the useful filtrate in the blood

Third process in the nephron

Secretion of the waste filtrate

Fourth process in the nephron

Reabsorption of water back into the blood

Aorta, renal artery and afferent artery

Where the blood starts flowing from the heart, to the kidneys and to the nephron structure

Glomerulus, bowman’s capsule

Filter— Blood that enters the glomerulus is very high pressured, and forces water and dissolved solutes to the bowmans capsule. Keeps blood cells and proteins in while forcing out water, nacl, uria, uric acid and glucose

Proximal tubule

Reabsorption— remaining cells contain lots of mitochondria for atp. Actively transports na and glucose and passively transports cl and h2o back into blood

loop of henle- descending

Reabsorption— Permeable to water, so lets water through passively

Loop of henle- ascending

Reabsorption— impermeable to water, so takes more energy,,

At first, passively lets na ascend but wll eventually needs atp to actively transports na up

Distal tubule

Reabsorption— actively reabsorbs na, passive cl and water

Secretion— h ions that change ph are actively secreted out, k ions are passively out

Collecting duct

Reabsorption— passively lets water back in

Secretion— secreted urine/uric acid out

pH balance

The human body is a strict 7.35-7.45

Kidney regulates this by taking in h+ (to lower) or hco3 (to raise)

Osmoregulation

Focuses on the anti diuretic hormone.

In the brain where it controls water absorption by increasing permeability of cells in distal tubule and collecting duct— helps with water reabsorption

When does osmoregulation happen?

Dehydration, exercising, or drinking alcohol or caffeine

osmoregulation

Special nerve receptors in the hypothalamus (brain) that detect change in the osmotic pressure

Negative feedback for adh

Anything dehydrating will increase osmotic pressure. Osmoreceptors in the brain shrink and release adh, which travels down to the distal tubule, increasing the permeability to collect water back into the body and decrease pressure . Also induces thirst lol

Alsosteren

Regulates blood pressure— increased solutes means a higher blood pressure

Controls na absorption by increasing permeability or cells in distal tubule and collecting duct, increasing na absorption. Basically reabsorbs nutrients if bp is low

Negative feedback for aldosterone

If bp is low, the brain released aldosterone— it travels to the distal tubule and collecting duct and increased permeability to nutrients. Letting them get back to the blood to raise the bp

Diabetes insipidus

Not enough adh- cant absorb excess water in which makes someone urinate and be thirsty excessively within a day

Diabetes mellitus

1- not enough insulin

2- receptors arent reactive to insulin

This no insulin or receptors to insulin— blood sugar stays high and glucose comes out of the urine instead of staying in the body

Brights disease (glomerulonephritus)

Inflamed kidney=inflamed glomerulus. Cannot properly filter blood and is associated with a high bp and heart disease