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Biology {Excretion School} 👏🏽 - Coggle Diagram
Biology {Excretion School} 👏🏽
Excretion
excretion
- the removal of metabolic waste products of chemical reactions from a living organism
metabolic waste-
the by-products of chemical reactions
metabolic waste need to be removed so there is not a build-up of toxins
Excretory Organs
stomata in leaves
- oxygen and water vapour
lungs
- CO2 and water vapor from aerobic respiration
kidneys
- urea, excess water and salts (mineral ions) to produce urine
skin
- water (mostly to lower body temperature) and salts from sweat glands
homeostatic
- regulates and controls internal conditions in a narrow range. The kidney is a homeostatic organ.
osmoregulation
- occurs in kidneys control body's water levels.
Urinary System
Kidneys (two bean-shaped organs) filter the blood making urine out of urea, mineral ions and excess water
This goes through two tubes called
ureters
to the bladder
In the
bladder
, urine is stored.
Urine is then released outside through the
urethra
renal artery
- comes from aorta delivering oxygenated blood to kidney that needs waste removed from it
renal vein
- carries deoxygenated blood back to the vena cava (heart to be pumped again) with no waste products
Excretory Products
amino acids
- excess amino acids cannot be stored in body-> broken down in liver (deamination) ammonia in urea
ammonia
urine
urine- toxic substance made the deamination of amino acids water, ions, and urea
water- dependent on how much ADH is secreted
salts/mineral ions- excess not filtered by the Loop of Henle(depending on water concentrations in body as well as the required concentration of mineral ions)
Kidney
Nephron
Bowman's capsule
- Collects filtrate from the glomerulus and transports it to the tubules.
proximal convoluted tubule
- Where glucose is reabsorbed into the blood by active transport
distal convoluted tubule
- reabsorption
Loop of Henlé
- Filters out salts/regulates water potential.
collecting duct
- Reabsorbs some water depending on the concentration of ADH in the blood.
glomerulus
- Filters blood by creating a region of high pressure. Liquid is referred to as
filtrate
.
Nephrons are responsible for filtering the blood
ADH
- antidiuretic hormone increases the permeability of the collecting duct to water
pituitary gland
- base of brain secretes ADH
hypothalamus
- detects water content in bloodstream
Ultrafiltration
When the blood is delivered through the renal artery, it makes its way through the afferent arterioles (which are small and wide) to the efferent arteriole (which are narrow) increasing the pressure in the glomerulus. Ultrafiltration is when high pressure forces filtrate (glucose, water, salts and urea) out of the blood through the glomerulus membrane and into the bowman's capsule.
Selective Reabsorption
- In the proximal convoluted tubule, glucose is reabsorbed through active transport, energy provided by many mitochondria. (people with diabetes cannot control their glucose levels so it ends up in the urine) Glucose needs to be reabsorbed into the blood to be used for respiration to produce energy.
Osmoregulation
- In the loop of henle, salt is pushed out into tissue, lowering the water potential of the tissue, allowing water to move into the blood by osmosis reabsorbing both salt and water into the bloodstream.
Selective Reabsorption
- In the distal covoluted tubule
Osmoregulation
- In the collecting duct, water returns to the blood stream depending on the concentration of antidiuretic hormone.
Exam Question
-
Explain why there are no plasma proteins in urine
The plasma proteins are too large to go through the capillary walls from the glomerulus to the bowman's capsule so it stays in the blood and returns to the heart through the renal vein.
Exam Questions
Why does selective reabsorption happen in the PCT
1) It has many mitochondria to provide energy through respiration for active transport.
2) The protein channels that reabsorb glucose into the bloodstream
What happens when there is too much water in the blood?
The hypothalamus detects high water levels in the blood. - The pituitary gland secretes less ADH.
Less ADH means the permeability of the collecting duct to water decreases.
-This reduces the water is reabsorbed, so water content in blood falls.
-The urine is light coloured, low in concentration, high in volume
What happens when there is too little water in the blood?
The hypothalamus detects low water levels.
The pituitary gland secretes more ADH.
ADH increases the the permeability of the collecting duct to water.
More water is reabsorbed into the blood so water levels rise.
The urine is dark coloured, concentrated and low volume.