5.1.2 Excreation Flashcards
What are features of the liver
Hepatic artery Hepatic portal vein Sinusoids Kupffer cells Canaliculi
What are liver cells known as
Hepatocytes
What vessels supply oxygenated blood to the liver
Hepatic artery and hepatic portal vein
Mixed in spaces called sinusoids
Outline the functions of the liver
Glycogen storage - glucagon binds to receptors in cell membrane,hepatocytes converts glucose to glycogen,
Urea formation - ammonia +CO2 to form urea
Outline the process of carbohydrate metabolism
Homeostatic control of glucose levels in blood
Glucose and insulin’s level rise, stimulate hepatocytes to convert glucose to glycogen
Outline the process of deamination of excess amino acids
Hepatocytes carry out transamination- conversion of one amino acid into another
Deamination - removal of an amine group from a molecule.
Removal of amino group -> convert to ammonia and rest for respiration or converted to lipids for storage.
What is the cycle known on where ammonia is converted to urea in a set of enzyme controlled reactions
Ornithine cycle
What is the role of Kupffer cells
Act as the resident macrophages of the liver- ingest foreign particles
How is bile secreted and where
Hepatocytes from the breakdown of the blood into spaces called canaliculi
What are nephrons
Functional units of kidneys
List the structures in the nephron
Bowmans capsule Proximal convoluted tubule Loop of Henle Distal convoluted tubule Collecting duct
What is the function of the bowmans capsule
Cup shaped structure
contains glomerulus
Where do many substance needed by the body get reabsorbed into the blood
Proximal convoluted tubule
What is the loop of Henle
Long loop of tubule that creates region with a very high solute concentration in the tissue fluid in kidney medulla
What is the distal convoluted tubule
Where fine tuning water balance takes place
Permeability of the walls varies in reasons to levels of the antidiuretic hormone(ADH)
Collecting duct
Urine passes down the collecting duct through the medulla to the pelvis
More fine tuning
Describe the network of blood vessels associated with each nephron
Renal artery, afferent arteriole,glomerulus, efferent arteriole, capillaries, renal vein
What is the responsibility of the nephron
Formation of urine
What are some of the causes of kidney failure
Structure of podocytes and the tubles themselves may be damaged/destroyed
Raised blood pressure that can damage the structure of the epithelial cells and basement membrane of the Bowmans capsule
Genetic condition e.g polycystic kidney disease
What are the effects of kidney failure
Loss of electrocyte balance- body can not excrete sodium,potassium and chloride ions causing osmotic inbalance
Build up toxic urea in the blood - body can nor get rid of urea and can poison cells
HBP- heart problems and strokes
Anaemia- rescue production of RBC as kidney involved in production of ERYTHOPOTEIN
What is glomerular filtration rate
Blood test that measures the level of creatine in the blood(breakdown product of muscles)
Units are cm3/min
What is haemodialysis
Involves a use of a dialysis machine
Partially permeable dialysis membrane, mimics the basement membrane of the BC
other side of membrane prevents loss of glucose and some mineral ions
What occurs when water potential is low in the blood
1) detected by osmoreceptors in hypothalamus if WP in blood is low, sends nervous impulse
2) ADH is secreted from posterior pituitary gland in blood
3) ADH binds to receptor membrane of collecting duct, triggers a secondary messenger inside the cell
Aquaporins(In vesicles) moved into cell membrane via micro tubles/ cytoskeleton
Leads to phosphorylation
H20 is absorbed out of CD into blood
4) smaller volume of conc. urine produced
Why do kangaroos have a longer loop of Henle
Longer ascending limb= more ions are actively pumped out into the medulla which creates a really low water potential meaning more water moves out from the collecting duct into the capillaries
What is removed from excess amino acid
Nitrogen containing amino group (-NH2)
Where does the ornithine cycle takes place
Mitochondria of liver cells
Cytoplasm
What do each lobule contain
Central vein in the middle that connects to the hepatic artery,hepatic portal vein and bile duct
