Chenele Mclean

A biological system that removes excess, unnecessary materials from an organism, in order to maintain homeostasis and prevent damage to the body.

The excretory system is responsible for removing metabolic and liquid toxic wastes, as well as excess water, in the form of urine.

Everyday, the kidney processes a large amount of blood to sort out as waste products and extra water.

- the waste and extra water become urine

Urine flows to your bladder through tubes called ureters.

Release three hormones:

- erythropoietin- renin- calcitriol

Kidney

Structure

•The kidneys are bean-shaped organs, about the size of our fist.

•They are located near the middle of our backs, just below the rib cage.

The renal cortex is the outer portion of the kidney between the renal capsule and the renal medulla.

Ultrafiltration occurs in the cortex

Erythropoietin is produced in the cortex

The innermost part of the kidney

-split up into a number of sections known as the renal pyramid

Contains the structures of the nephronsresponsible for maintaining the salt and water balance of the blood

Hypertonic to the filtrate in the nephron and aids in the reabsorption of water

The ability to maintain a stable internal environment within the body in response to environmental changes.

Kidneys measure out chemicals like sodium, potassium, and phosphorus and release them back to the blood to return to the body

When the blood pressure is too low renin is released renin stimulates the contraction of the blood vessels resistance to blood flow increases (which means an increase in bp) bp returns to normal kidneys stop releasing renin

Osmoregulation is a process which regulates the salt and water balance in the body to maintain the blood osmotic pressure.

When blood osmotic pressure is high (blood too salty), ADH is released and causes more water to be absorbed in the kidney in comparison to salt.

When blood osmotic pressure is low (blood is dilute), aldosterone is released and more salt is absorbed in the kidney causing more water to be excreted via urine.

The kidneys have two very important roles in maintaining the acid-base balance:

- to reabsorb bicarbonate from urine

- to excrete hydrogen ions into urine

Kidneys play several roles in the body- most importantly they play a major role in maintaining homeostasis in the body.

If ADH holds water in the body decreasing urine output and increasing blood pressure, does a person with high blood pressure (holding water) have a high ADH blood level or a low ADH blood level?

*Exam Krackers

Low ADH because the ADH output responded to the body.

A secondary effect of aldosterone is to increase blood pressure. Would expected aldosteronelevels be high or low in a person with low blood pressure?

*Exam Krackers

Expected aldosterone levels would be higher than normal. Since aldosterone increases blood pressure, and the body tries to bring blood pressure back to normal, the adrenal cortex releases more aldosterone into the blood.