Excretion
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- Created by: ievs
- Created on: 19-11-20 21:23
what is excretion?
removal of of the waste products of metabolism from the body
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why do we need excretion?
- maintains normal metabolism
- maintains homeostasis by keeping levels of certain substances roughly the same
- maintains homeostasis by keeping levels of certain substances roughly the same
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why get rid of excess amino acids?
nitrogenous substances that cannot be stored by the body - damaging
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describe breakdown & removal of amino acids
1) DEAMINATION
NH2 groups removed from amino acids >>>> NH3
and Keto acids formed
2) Keto acids are respired to give ATP or converted to
glycogen
3)ORNITHINE CYCLE
NH3 is too toxic to excrete directly.
NH3 >>>>>>> urea (CH₄N₂O)
4) urea is relea
NH2 groups removed from amino acids >>>> NH3
and Keto acids formed
2) Keto acids are respired to give ATP or converted to
glycogen
3)ORNITHINE CYCLE
NH3 is too toxic to excrete directly.
NH3 >>>>>>> urea (CH₄N₂O)
4) urea is relea
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describe the ornithine cycle
1) NH3 + CO2 ornithine >>>> citruline + H2O
2) citruline + NH3 >>>> arginine + H2O
3) arginine + H2O >>>> ornithine + urea (CH₄N₂O)
2) citruline + NH3 >>>> arginine + H2O
3) arginine + H2O >>>> ornithine + urea (CH₄N₂O)
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how does liver break down alcohol(ethanol)?
ethanol >>>> ethanal (oxidation!)
ethanal >>>> ethanoic acid (oxidation!)
ethanal >>>> ethanoic acid (oxidation!)
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how does chronic drinking affect the liver?
- excess alcohol can be stored as fat - fatty liver.
fatty liver can lead to scaring due to inflammation of
liver
- can lead to CIRRHOSIS of the liver
liver cells die & scar tissue blocks blood flow.
fatty liver can lead to scaring due to inflammation of
liver
- can lead to CIRRHOSIS of the liver
liver cells die & scar tissue blocks blood flow.
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Why is too much paracetamol bad?
leads to liver/kidney failure
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what does liver break down?
- amino acids
- alcohol
- paracetamol
- insulin
- alcohol
- paracetamol
- insulin
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what does liver store?
glycogen
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what does hepatic artery do?
-supplies the liver with oxygenated blood from the heart
- provides plenty of O2 to the liver for respiration - VERY ACTIVE
- provides plenty of O2 to the liver for respiration - VERY ACTIVE
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what are liver cells called?
hepatocytes
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what does hepatic vein do?
carries deoxygenated blood out of the liver to the heart/lungs
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what does hepatic portal vein do?
- brings blood from duodenum and ileum (parts of small intestine) full of products of digestion (both good and harmful).
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what does bile duct do?
- takes bile produced by liver to be stored in the gall bladder.
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what is liver made of?
liver lobules
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name all components/structures of liver lobules
- hepatocytes
- central vein
- hepatic vein
-hepatic artery
- hepatic portal vein
- bile duct
- sinusoids
- kupffer cells
- canaliculi
- central vein
- hepatic vein
-hepatic artery
- hepatic portal vein
- bile duct
- sinusoids
- kupffer cells
- canaliculi
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what are sinusoids?
capillaries
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what are canaliculi?
cappilaries / tubes
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what do sinusoids connect?
hepatic artery and hepatic portal vein to central vein
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what do canaliculi connect?
bile duct and central vein
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what do kupffer cells do?
Remove bacteria and break down old red blood cells
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what do hepatocytes do?
breakdown harmful material
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what components make up kidney excretion system?
- renal artery
- renal vein
- cortex
- medulla
- renal capsule
- ureter
- bladder
- urethra
- renal vein
- cortex
- medulla
- renal capsule
- ureter
- bladder
- urethra
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what components are in nephron's cortex?
- renal artery
- afferent arteriole
- glomerulus
- bowman's capsule
- efferent arteriole
- proximal convoluted tubule (PCT)
- distal convoluted tubule (DCT)
-collecting duct
- afferent arteriole
- glomerulus
- bowman's capsule
- efferent arteriole
- proximal convoluted tubule (PCT)
- distal convoluted tubule (DCT)
-collecting duct
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what components are in nephron's medulla?
- loop of Henle
- collecting ducts
- efferent arteriole
- collecting ducts
- efferent arteriole
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describe the order of blood flow in a nephron.
renal artery >>> afferent arteriole >>>> glomerulus >>>> efferent arteriole (spreads all over the nephron) >>> renal vein
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describe the order of substance movement in a nephron
Bowman's capsule >>>> proximal convoluted tubule (PCT) >>>> loop of Henle >>>> distal convoluted tubule >>>>> collecting duct >>>> ureter
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describe how blood is filtered in nephrons
1) blood from renal artery >>>> arterioles in the cortex
2) each arteriole splits into glomerulus (bundle of capillaries in the bowman's capsule)
3) ultrafiltration takes place
blood in the glomerulus is under high pressure due
to smaller capillary
2) each arteriole splits into glomerulus (bundle of capillaries in the bowman's capsule)
3) ultrafiltration takes place
blood in the glomerulus is under high pressure due
to smaller capillary
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how are useful substances reabsorbed in the nephron tubules?
selective reabsorption in PCT, loop of Henle, and DCT.
useful substances leave the tubules in the nephron and enter the capillaries in the capillary network wrapped around them.
the epithelium of the PCT forms microvilli to provide a large SA for reabso
useful substances leave the tubules in the nephron and enter the capillaries in the capillary network wrapped around them.
the epithelium of the PCT forms microvilli to provide a large SA for reabso
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what is urine usually made of?
- water
- dissolved salts
- urea
- hormones, excess vitamins, etc.
- dissolved salts
- urea
- hormones, excess vitamins, etc.
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What doesn't urine usually contain?
- proteins
- blood cells
- glucose
- amino acids
- vitamins
- blood cells
- glucose
- amino acids
- vitamins
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Describe reabsorption in PCT
Sodium - potassium pumps pump out Na+ ions into the blood capillary >>>> reduces the conc. of Na+ in cytoplasm of PCT cells.
Na+ is transported from filtrate in PCT lumen into the PCT cells, carrying glucose and amino acids through facilitated diffusion.
Na+ is transported from filtrate in PCT lumen into the PCT cells, carrying glucose and amino acids through facilitated diffusion.
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what happens if water potential of blood is low?
more water is reabsorbed in the blood by osmosis from nephron tubules
therefore urine is more concentrated due to having less water content
therefore urine is more concentrated due to having less water content
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what happens if water potential of blood is high?
less water is reabsorbed by osmosis into blood
therefore urine is more dilute
therefore urine is more dilute
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what mechanism does loop Henle use for reabsorption?
counter current exchange mechanism
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describe reabsorption in loop of Henle?
at the top of ascending limb Na+ and Cl+ are actively pumped out into the medulla. water is not moved out since the ascending limb is water impermeable >>>> low water potential in medulla.
because water potential is lower in medulla than in descending li
because water potential is lower in medulla than in descending li
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what influences the volume of water reabsorbed?
collecting duct has changing permeability (due to levels of ADH released)
different animals have different lengths of loops of Henle. The larger the loop of Henle, the more water is reabsorbed from the filtrate.
different animals have different lengths of loops of Henle. The larger the loop of Henle, the more water is reabsorbed from the filtrate.
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why do desert animals have long loops of Henle?
more water moves out of the nephron and collecting duct into capillaries >>>> produces concentrated urine
less water is lost through excretion.
less water is lost through excretion.
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how is water reabsorption controlled in the body?
water potential is being monitored by osmoreceptors in hypothalamus.
once osmoreceptors are stimulated by low water potential in the blood, nerve impulses are sent from hypothalamus to posterior pituitary gland to release antidiuretic hormone (ADH)
ADH
once osmoreceptors are stimulated by low water potential in the blood, nerve impulses are sent from hypothalamus to posterior pituitary gland to release antidiuretic hormone (ADH)
ADH
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what happens when you are dehydrated?
water potential of blood drops, and that is detected by the osmoreceptors in hypothalamus.
posterior pituitary gland is stimulated to release more ADH into the blood >>>> increases water permeability in DCT and collecting duct >>>> more water is reabsorb
posterior pituitary gland is stimulated to release more ADH into the blood >>>> increases water permeability in DCT and collecting duct >>>> more water is reabsorb
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when happens when you are hydrated/overhydrated?
water potential increases, which is detected by the osmoreceptors in the hypothalamus.
posterior pituitary glands release less ADH into the blood.
less ADH means that the DCT and collecting duct are less permeable, so less water is reabsorbed into the b
posterior pituitary glands release less ADH into the blood.
less ADH means that the DCT and collecting duct are less permeable, so less water is reabsorbed into the b
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what is kidney failure?
when the kidneys cannot carry out their normal function, they stop working properly
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how is kidney failure detected?
by measuring glomerular filtration rate (GFR) - the rate at which your blood is filtered from glomerulus to bowman's capsule
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what can cause kidney failure?
kidney infections
they cause inflammation ofkidney which can
damage cells & interfere with ultrafiltration or
reabsorption
high blood pressure
can damage glomeruli as capillaries already have a
high blood pressure. if the pressure gets too high
they cause inflammation ofkidney which can
damage cells & interfere with ultrafiltration or
reabsorption
high blood pressure
can damage glomeruli as capillaries already have a
high blood pressure. if the pressure gets too high
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what kind of problems does kidney failure cause?
waste products(e.g. urea) that kidneys would usually remove start to accumulate in blood. too much urea >>>>> weight loss and vomiting
fluids start to accumulate in tissues since kidneys can't remove excess water from blood >>>> swelling
the levels of e
fluids start to accumulate in tissues since kidneys can't remove excess water from blood >>>> swelling
the levels of e
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how does haemodialysis work?
patients blood is passed through dialysis machine
counter current exchange blood flows one way, while dialysis fluid flows in opposite direction through partially permeable membrane
waste products, excess water and ions diffuse across the membrane into
counter current exchange blood flows one way, while dialysis fluid flows in opposite direction through partially permeable membrane
waste products, excess water and ions diffuse across the membrane into
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How does peritoneal dialysis work?
dialysis fluid is flown from a tube into the patient's abdominal cavity (outside the patient's abdomen)
waste product diffuse out of patient's blood into the dialysis fluid via peritoneum(membrane lining the abdominal cavity)
the fluid is drained out v
waste product diffuse out of patient's blood into the dialysis fluid via peritoneum(membrane lining the abdominal cavity)
the fluid is drained out v
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pros of kidney transplant
- cheaper (long term)
- more convenient than having repeated dialysis sessions
- better quality of life
- more convenient than having repeated dialysis sessions
- better quality of life
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cons of kidney transplant
- risky operation
- immune system may reject the transplant - immunosuppressants needed
- immune system may reject the transplant - immunosuppressants needed
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how does a pregnancy test work?
when pregnant, women produce the hormone called human chorionic gonadotropin (hCG).
this hormone is only found in urine.
the pregnancy test contains blue beads that have monoclonal antibodies that only bind to hCG attached to them in the application are
this hormone is only found in urine.
the pregnancy test contains blue beads that have monoclonal antibodies that only bind to hCG attached to them in the application are
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testing presence of steroids
athletes may use anabolic steroids (testosterone, nandrolone) that help build muscle tissue.
athletes are prohibited from using them as it is unfair to other athletes and some steroids can be dangerous and cause things such as liver failure >>>> testing
athletes are prohibited from using them as it is unfair to other athletes and some steroids can be dangerous and cause things such as liver failure >>>> testing
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testing presence of recreational drugs
involves using test *****s with antibodies that will bind to the drug r ts by products. if enough drug is present, the test ***** will change its colour, indicating a postive result.
if the result is positive, then the sample is sent out for further test
if the result is positive, then the sample is sent out for further test
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Other cards in this set
Card 2
Front
- maintains normal metabolism
- maintains homeostasis by keeping levels of certain substances roughly the same
- maintains homeostasis by keeping levels of certain substances roughly the same
Back
why do we need excretion?
Card 3
Front
nitrogenous substances that cannot be stored by the body - damaging
Back
Card 4
Front
1) DEAMINATION
NH2 groups removed from amino acids >>>> NH3
and Keto acids formed
2) Keto acids are respired to give ATP or converted to
glycogen
3)ORNITHINE CYCLE
NH3 is too toxic to excrete directly.
NH3 >>>>>>> urea (CH₄N₂O)
4) urea is relea
NH2 groups removed from amino acids >>>> NH3
and Keto acids formed
2) Keto acids are respired to give ATP or converted to
glycogen
3)ORNITHINE CYCLE
NH3 is too toxic to excrete directly.
NH3 >>>>>>> urea (CH₄N₂O)
4) urea is relea
Back
Card 5
Front
1) NH3 + CO2 ornithine >>>> citruline + H2O
2) citruline + NH3 >>>> arginine + H2O
3) arginine + H2O >>>> ornithine + urea (CH₄N₂O)
2) citruline + NH3 >>>> arginine + H2O
3) arginine + H2O >>>> ornithine + urea (CH₄N₂O)
Back
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