Term 1 Lesson 9: Kidneys Flashcards
What is excretion?
The removal of waste products
3 different excretory organs
- skin - excrete carbon dioxide and sweat
- lungs - excrete carbon dioxide and sweat
- kidneys - urine
Blood needs to have the perfect amount of water, salt and other solutes. What happens if it doesn’t?
It bursts or shrinks
Role of the kidneys
urine = water + urea + salt
What system are the kidneys a part of?
urinary system
What muscles control when you urinate
sphincter muscles
What product sare excreted from the body as urine
excess:
- water
- salts
- ammonia (nitrogenous waste)
- urea (nitrogenous waste)
Osmoregulation
Keeping the water and salt content of the internal body environment constant
Homeostasis
Maintaining a constant internal environment
Urine
- Fluid stored in the bladder and discharged through the urethra.
- Composed of mainly water, salts and nitrogenous waste products.
what hormone is osmeoregulation controlled by?
ADH (Anti-diuretic hormone).
Where is ADH is produced?
pituitary gland
What does ADH do?
tells your kidneys to absorb water back into the blood.
Label 1
glomerulus
Label 2
Bowmans capsule
Label 3
collecting duct
Label 4
First convilated tubule
Label 5
Loop of henle
Label 6
Descending limb
Label 7
Ascending limb
Label 8
Distal convulet tubule
Glomerulus
Ball of capillaries nestled in the Bowmans capsule
How does the kidney produce urine in the nephron?
- Blood enters the nephron from the renal artery into the glomerulus. This is a ball of capillaries nestled inside the Bowman’s capsule.
2.Because the blood was squeezed into this ball of capillaries it has high pressure. Small molecules (glucose, salts, urea and water) from the blood plasma are forced through the capillary wall and another barrier called the basement membrane. This is called ultrafiltration. They enter the Bowman’s capsule. This fluid is now called glomerular filtrate. The large molecules that could not fit through continue out of the glomerulus staying in a blood vessel that is always touching the nephron.
- Glomerular filtrate moves along the nephron to the proximal convoluted tubule. Here glucose is reabsorbed back into the blood. Glucose is needed by the body. We don’t want to waste it in urine. If you do have glucose in your urine something is wrong. Notice in the diagram how the proximal convoluted tubule is touching the blood vessel? This is where it can pass into the blood by active transport (because there is more glucose in the nephron than the blood).
- The glomerular filtrate carries on to the distal convoluted tubule. The levels of salt need to be just right to keep our blood cells from shrinking or bursting. If the blood needs more salt it will be reabsorbed from here (notice again the blood vessel touching the tubule). Excess salt will stay in theglomerular filtrate. This happens by active transport.
- Glomerular filtrate moves on to the collecting duct. The levels of water also need to be just right for blood cells. If blood water content is low water is absorbed into the blood by osmosis. If water content is high excess water is remains in the nephron. Balancing blood water and salt content is called selective reabsorption because the kidney can choose whether they’re reabsorbed into the blood.
- You now have urine. It is released from the nephron containing salts, urea and excess water.
- Clean filtered blood carries on to the renal vein to be transported around the body.
Label 4
cortex - The outer edge of the kidney.
Label 6
medulla - inner portion of kidney that contains many pyramids with millions of nephrons
Label 5
Renal pelvis - collecting ducts release urine into a space called the pelvis.
The pelvis is connected to the ureter