Excretory Flashcards
(50 cards)
What are the three main functions of the kidneys
- Remove wastes
- Balance blood pH
3a. Maintain water balance
3b. Blood pressure
How many kidneys does the body have
What are they made up of
2
1 million nephrons
What are some wastes removed by the kidney?
How is uric acid formed?
What is the process it is formed in called?
Urea and uric wastes from the blood
Uric acid is formed from the breakdown of DNA
Urea I’d formed in a process called deamination
Where does deamination occur?
What is it
Liver
The conversion of amino acids in the blood to carbohydrates (urea is produced)
What are the steps to deamination
- NH3 is removed from amino acids
2. 2 NH3 + CO2 = urea
What is the build up of uric acid called?
Gout
How do the kidneys maintain pH balance
CO2 from peritubular capillaries + H2O in cells lining the nephron = carbonic acid
Carbonic acid breaks apart to make H+ and HCO3
What happens if the blood is too acidic
H+ is excreted in the urine and HCO3- is reabsorbed back to the blood …buffering the blood
What happens when the blood is too basic
HCO3- is excreted in the urine and H+ is reabsorbed back to the blood
How much water moves though the kidneys in one day?
How is 2L of water lost per day
How much water is reabsorbed
180L
Perspiration, exhaling, urine
178L
What happens of 1% water loss
5%
10%
1- thirst
5- pain and collapse
10- death
What two hormones regulate water concentration in the blood
Antidiuretic hormone (ADH) Aldosterone
What does ADH do
Where is it stored
Targets the distal tubule of the nephrons and collects dust
It increases H2O reabsorption into the bloodstream
Stored in posterior pituitary gland
What dies water lost in the body cause?
Causes water to move from tissues into the bloodstream
Osmoreceptors in the hypothalamus detect low osmotic(water) pressure
How does the hypothalamus respond to loss of H2O
Triggers thirst, send nerve message to the pituitary to stimulate the release of ADH
ADH travels in blood and targets the nephron
What is the effect of ADH on the nephron
ADH causes the distal tubule and collecting duct to become permeable to H2O
The kidneys reabsorb more H2O
A more concentrated urine is produced
What factors affect ADH
What happens when the release of ADH is inhibited
Cold-weather, caffeine, and alcohol all inhibit the release of ADH
Reabsorption of water can’t take place and urine volume is increased
What do the kidneys help regulate
Blood pressure
Where is aldosterone produced and what does it do
Produced and secreted by the adrenal glands
Targets the ascending loop of Henle, distal tubule, and collecting duct. Also increases the amount of sodium reabsorption… Therefore increasing the reabsorption of water, this increases blood pressure
What is low blood pressure detected by
Osmo receptors in the juxtaglomerular apparatus
What do cells in the juxtaglomerular apparatus release and what does it do
Renmin which converts angiotensinogen to angiotensin
What is angiotensinogen
What does it do
A plasma proteins secreted by the liver
Constricts blood vessels and causes aldosterone to be released from the adrenal glands
What do renal arteries do
what do renal veins do
Supply kidneys with oxygenated unfiltered blood
Remove deoxygenated filtered blood
What do kidneys do
How many layers are there and what are they
Filter wastes from the blood
Three layers
Cortex is outer layer of connective tissue
Medulla is inner layer which contains the nephrons
Pelvis is hollow chamber joining kidney to ureter
