Organ System - Excretory Flashcards
What hormones does kidney release?
It releases hormone to the endocrine system. Such as:
Erythropoietin that promotes production of red blood cells (erythropoiesis)
Calcitriol (vitamin D3): Allows digestive tract to absorb calcium
What is kidney composed of?
Cortex (outer layer)
Medulla
Renal Pelvis
What’s ureter?
A tubular structure connected to pelvis that helps transport the urine produced by nephrons to the bladder for storage
What’s a nephron and what’s it composed of?
Tube made of simple epithelium lining and contains five sections;
1. Bowman’s capsule: allows the filtrate (fluid) to come in
2. Proximal convoluted tubule: solute can be added to filtrate
3. Loop of Henle
4. Distal convoluted tubule:
5. Collecting duct:
What’s osmolarity?
Sum of concentrations of all solutes dissolved in a solvent
What does nephron do to increase concentration of solute?
It secretes ions into the filtrate
What are the four solutes that our body need to secrete into the filtrate? And why?
It secretes to prevent them from building up in blood
1. Hydrogen ions
2. Urea
3. Ammonia (NH3)
4. Potassium (K+)
How does the nephron increase and decrease filtrate concentration in loop of henle?
Concentration increases down the loop of henle by reabsorbing water from filtrate and decreases by removing the solutes before it goes upward
What happens right before filtrate enters in collecting duct?
Filtrate needs to be more concentrated when entering medulla so kidney secretes HUNK ions
How do kidneys take solutes and water that’s reabsorbed and get then back into blood?
By contrast countercurrent multiplier system which uses a vein called vasa recta that flows in opposite direction from nephron to pick up solutes in water.
It absorbs water from loop of henle and glucose, amino acids, vitamins, ions, and water from proximal convoluted tubule
What’s osmoregulation?
It is the regulation of osmotic pressure in body fluids to maintain homeostasis
How does kidney maintain homeostasis and what hormones are used?
By maintaining the osmoregulation (pressure) and volume of fluid
Aldosterone: released when blood is under hydrated (blood volume or pressure or low). It increases sodium reabsorption that results in reabsorption of water as well
ADH (anti diuretic): released when blood is too dilute I.e. over hydrated. So it inserts aquaporins or water channels into the stream to reabsorb the water in collecting duct
What kind of sensors are involved?
Osmosensors: detect if blood if diluted
Glomerular capillaries: sensors that detect when volume or pressure or low. This is when kidneys and liver work together
What do kidneys and liver release to increase blood pressure?
Kidneys: Renin
Liver: Enzyme called angiotensinogen
How is aldosterone released?
Steps:
1. Kidney releases renin and liver releases angiotensinogen
2. Renin coverts angiotensinogen ➡️ angiotensin I (using ACE) ➡️ angiotensin II
3. Angiotensin II causes adrenal cortex to release aldosterone
