Excretion Flashcards
Peritoneal dialysis
- layer of tissue that lines the abdominal cavity
- dialysis fluid injected into the peritoneum through a catheter and left to exchange
- drained off after half/three quarters of an hour
- repeated up to 3x a day
Kidney transplant
- most effective treatment
- but short supply & have to be a close match
Peritoneal
- layer of tissue that lines the abdominal cavity
Haem vs peritoneal dialysis
Haem - more efficent - less frequent - less risk of infection Peritoneal - less time consuming - less expensive - less controlling of diet
Haemodialysis
- blood from a patients artery travels through small tubes soaked in dialysis fluid
- fluid has the right concentration of nutrients to diffuse in and out
- anticoagulant added
- & returned to a vein
- every few days takes about 3 hours
Chronic kidney failure
- usually caused by inflammation of the glomeruli
- common in older people with diabetes
- unlikely to recover
Acute kidney failure
- maybe when have other conditions
- following surgery
- inflammation in the glomeruli
- sepsis
- likely to recover
Pregnancy testing
- use monoclonal antibodies to detect for human chorionic gonadotrophin (HGC)
- for antigen- antibody complex
- forms another antigen complex with immobilised antibodies
- lines up coloured particles that form a line if colour
Urine for diagnosis
- can find the products in urine -> give clues for diagnosis
- used for drugs testing
- show pregnancy
ADH
- anti-diuretic hormone
- synthesised in the cell bodies of osmoreceptors
- binds to receptors on the collecting duct& increases permeability to water
- more aquaporin channels
Osmoregulation (stages)
- blood found to be concentrated by osmoreceptors in the hypothalamus
- stimulate neurosecretory cells that produce and secrete ADH down their axon to the terminal bud in the posterior pituitary gland
- travels in the blood to the kidney
- causes aquaporin proteins to insert themselves in the plasma membrane of the collecting duct
- water can pass through back into the blood
Osmoreceptors
- sensory neurones in the hypothalamus
- sensitive to the water potential in the blood
- they produce ADH which travels down the axon & released into the blood from the posterior pituitary gland
Osmoregulation
- the regulation of the water content of the body
Collecting duct
- can be made more permeable to water by ADH
- also water passes back through tge medulla do to the low water potential so more water reabsorbed by osomosis
Distal convoluted tubule
- actively transports na+ ions out
- actively transports k* ions in
Descending limb (loop of henle)
- permeable to water and ions
- allows water to move out by osmosis to the low water potential in the medulla
Counter current system
- fluid flows in 2 vessels close to each other
- in opposite directions
- to maximise concentration gradients
Ascending limb (loop of henle)
- impermeable to water
- permeable to na+ cl-
- ions are actively transported out into the medulla
- later diffuse out
Selective reabsorption (stages)
- Na+ actively transported out of cells into tissue fluid = conc gradient
- Na+ & amino acids/glucose travel through carrier proteins through facilitated diffusion& diffuse into tissue fluid (and some actively transported)
- increase in water potential in glomerular filtrate
- water moves down the water potential gradient by osmosis into cells into tissue fluid
Selective reabsorption
The absorption of wanted molecules from the glomeruli filtrate back into the blood in the proximal convoluted tubule
Bottleneck effect
- in the glomerulus
- formed by the larger afferent arteriole and smaller efferent arteriole
- and a build up of hydrostatic pressure
Renal capsule epithelium
- formed of podocytes
- that have major processes that join together to leave tiny slits
Endothelium of blood capillaries
- has small pores to allow plasma and small molecules to move in and out
Basement membrane
- A layer of connective tissue
- collagen and glycoproteins
- holds the epithelium in place
- doesnt let molecules bigger than 69,000 through
Ultrafiltration
- filters out small molecules from the blood into the glomerulus under high pressure
Nephrons
- a kidney tubule
- made up of glomerulus, proximal convoluted tubule, loop of henle, distal convoluted tubule, collecting duct
Kidney structure
- blood from renal artery take away by renal vein
- dark outer cortex
- lighter medulla
- inner white pelvis attached to ureter
Detoxification of other substances in the liver
- breaks down hormones ie testosterone
- breaks down drugs
Cirrohosis
- damaged hepatocytes are replaced by fibrous tissue
- lose structure of blood supply
- lots of health risks ie liver disease
Fatty liver
- if lots of alcohol consumed + (obesity& diabetes)
- lots of nadRED
- no nad for respiration
- fatty acids accumulate and form fat stores in hepatocytes reducing efficiency
Ammonia
- NH3
- very soluble & very toxic
- combines with CO2 to form urea
Deamination
- The removal of the amino group from an amino acid
- in the liver
- and forms ammonia
Kupffer cells
- macrophages that line sinusoids
- they capture and destroy bacteria by phagocytosis
Sinusoids
- channels in the lobules of the liver
- mix blood from the hepatic artery and hepatic portal vein
- lined with hepatocytes and kupffer cells
Bile canaliculi
- channels between cells in the liver that carry bile
Bile
- made in the liver
- stored in the gall bladder
- contains bile salts which helps to emulsify lipids
Hepatocytes
- liver cells
- lined with microvilli
- remove excess molecules from the blood
- perform protein synthesis
- perform bile synthesis
- detoxification
- pass other molecules into the blood
Ornithine cycle
Ornithine -> CO2 + NH3 (lose H2O) -> citruline -> NH3 (lose H2O) -> arginine -> H2O -> urea
Detoxification of alchohol
Ethanol -> alcohol dehydrogenase + reducing NAD -> Ethanal -> aldehyde dehydrogenase + reduces NAD -> ethanoate (acetate) -> Krebs cycle
Liver structure
- made up of lobules centred around a branch of the hepatic vein
- blood from the hepatic artery and portal vein mix in sinusoids
- next to bile canaliculi flowing in the opposite direction to a branch of the bile duct
Hepatic vein
- takes blood away from the liver to the vena cava
Hepatic portal vein
- from the small intestine & brings blood rich in nutrients
- but deoxygenated and low pressure
Hepatic artery
From the aorta delivers oxygenated blood to the liver
Urea
- made in the liver from excess amino acids
- transported to the kidneys where filtered out& stored in the bladder as urine
Excretion
- the removal from the body of metabolic waste
- mainly CO2 and urea
