Excretion Flashcards
what is excretion?
process of removing metabolic waste products from the body
What are examples of waste products in the body? How are each produced?
CO2- produced during respiration
Bile- produced when haemoglobin broken down
nitrogenous waste- produced when amino acids broken down
What are the three blood vessels in the liver?
Hepatic artery
Hepatic vein
Hepatic portal vein
Role of Hepatic artery?
Provide oxygenated blood has nutrients from the heart
Role of Hepatic vein?
moves deoxygenated blood out of liver to the heart
Role of Hepatic portal vein?
moves deoxygenated blood , nutrient filled, from digestive system
The liver is the main organ used in the excretory system, what cells make up the liver?
Hepatocytes
What capillary surrounds hepatocytes?
sinusoids , connected to hepatic artery, hepatic vein and central vein
name 3 functions of the liver?
- stores glycogen needed to regulate blood glucose levels
- break down toxic substances Ie: alcohol through detoxification
- break down access amino acids through deamination
how are amino acids broken down through deamination? what product is made?
- amine group remove from amino acid by deamination
- amine group converted into ammonia
- ammonia too toxic for body, so combined with carbon dioxide to produce urea
- urea excreted via urine out the body
remainder of amino acids used for respiration
what cycle is used when ammonia combined with co2 to produce urea?
ornithine cycle
what is the role of the kidney?
filter the blood to make urine through getting rid of excretory products, like urea
what is the main structure of the kidney that produces urine?
nephron
what makes up the nephron in the correct order?
- afferent arteriole snd efferent arteriole
- glomerulus
- Bowmans capsule
- proximal convoluted tubule
- loop of henle
- distal convoluted tubule
- collecting duct
what is the difference between the afferent and efferent arterioles? what do they cause?
lumen size - afferent has a larger lumen
creates filtrate pressure in glomerulus forcing substances out
what does the hormone ADH do?
controls permeability of collecting duct wall
why is the efferent arteriole wrapped around the whole nephron?
needed for selective reabsorption of useful materials
what happens if there is more ADH
more ADH = more permeable the wall = more water reabsorbed
what is osmoregulation?
regulation of blood water levels
explain selective reabsorption in the nephron
- proximal convoluted tubule - all glucose, amino acids, vitamins and hormones reabsorbed by active transport
- some sodium ions also reabsorbed by active transport
- movement of sodium ions changes water potential
- leads to water being reabsorbed by osmosis , which causes filtrate to now be more concentrated
- chloride ions leave by diffusion to be reabsorbed now - loop of henle
- water continues to be reabsorbed
- move down depending limb, ion concentration increases - hypertonic point reach at bottom of decending limb and ascending limb, meaning a very high salt conc
- causes salt to be easily reabsorbed by diffusion - ascending limb
- conc of salt decreases in filtrate
- isotonic level reached where salt level inside and out of nephron the same
- causes more salt to be reabsorbed by active transport - distal convulated tubule
- salt, water reabsorbed if the body needs it
- water if needed absorbed via ADH
- anything reabsorbed to balance salt and water level and to regulate blood ph level - collecting duct
- water reabsorbed by ADH and osmosis
- as go down collecting duct , cells can change the conc of salt in tissue fluid, causing a steep water concentration gradient
- ADH tells tubule wall more aquaporins needed for more water reabsorption
what is used in ultrafiltration in the nephron?
afferent and efferent arteriole
endothelium cell wall
basement membrane
bowsman capsule
podocytes
peducils
what are podocytes , role?
on Bowmans capsule cell wall acting as second filter
contain peducils preventing large molecules like RBC entering filtrate
what detects the change in water potential in the blood?
osmoregulators
where are the osmoregulators in the body?
hypothalamus
where is ADH produced and where is it released?
produced in hypothalamus
related in pituitary gland
what are two treatments used to treat kidney failure?
kidney dialysis and kidney transplant
how is kidney failure determined?
through glomerular filtration rate if falls below 15
what are the two types of kidney dialysis ?
haemmodialysis
peritaneal
explain haemodialysis for kidney dialysis
patients blood taken from their artery and passed through dialysis machine to remove harmful molecules and adjusts the chemicals - ions and water - in blood to normal ranges
blood returned to patients vein
what role of the Bowmans capsule does the renal dialysis take?
basement membrane forming a partially permeable membrane
what is peritoneal dialysis?
abdominal cavity filled with dialysis fluid from catheter
in peritoneal dialysis what is the abdominal cavity surrounded by?
peritoneum membrane acting as filter
disadvantages of haemodialysis?
3x week at hospital
several hours
restricted diet
pros of peritoneal dialysis
done at home
frequent so molecules in blood kept stable
how does diagnostic testing work? what does it use?
works through using urine samples, to test chemicals in the urine to diagnose medical conditions
what hormone is produced in pregnancy which used to test whether someone is pregnant?
hCG
what antibody is used to test for the presence of hCG in the urine?
monoclonal antibodies
describe the steps with how monoclonal antibodies for hCG produced
- mouse injected with hCG
- b lymphocytes extracted from
spleen of mouse (some of the antibodies produced against hCG) - b lymphocytes have a short life span so fused with cancer cell - myeloma producing hybridoma cells
- only some hybridoma cells produce antibodies against hCG
- hybridoma cells screened - identifying what cells produce antibodies against hCG
- correct cell found , cultured to produce millions of copies of original hybridoma
- antibodies to hCG purified
describe how a pregnancy test works
- place end of wick into urine in the morning, morning will contain highest conc of hCG
- wick contains monoclonal antibodies to hCG
- antibodies bind to hCG forming hCG Antibody complex
- urine and antibodies make way up wick
- at certain point on wick will contain immobilised antibodies which cannot move
- immobilised antibodies bind to hCG antibody complex
- beads form pink strip across wick if pregnant
- some antibodies did not bind to hCG , so the unbound antibodies continue to move up strip
- further up wick another line of immobilised antibodies forming second pink strip which is the control strip telling us whether the test working or not
