Chapter 15- Homoestasis Flashcards
(37 cards)
Define ectotherms
Use surroundings to warm their bodies and are heavily dependent on environment
Define endothermic
Control own body temp and doesn’t rely on environment
Define vasodilation
The arterioles near the surface of the skin dilate when the temperature rises
Define vasoconstriction
The arterioles near the surface of the skin constrict.
Define excretion
Is the removal of the waste products of metabolism from the body
The main metabolic waste products in mammals are:
Carbon dioxide- one of waste products of respiration excreted from the lungs
Bile pigments- formed from the breakdown of haemoglobin from old red blood cells in the liver. They are excreted in the bile from the liver into the small intestine via gall bladder and Bile duct they colour the faeces
Nitrogenous waste products- formed from the breakdown of excess amino acids by the liver. All mammals produce urea as their nitrogenous waste. Fish produce ammonia while birds and insects produce uric acid. Urea is excreted by the kidneys in the urine
What vessels supplies oxygenated blood
Hepatic artery
What vessel returns blood back to heart
Hepatic vein
What other vessel supplies blood to liver
Hepatic portal vein
What is the ornithine cycle?
Removing the amino group from the amino acid and converting the highly toxic ammonia to the less toxic and more manageable compound urea.
What is the kidney made up of?
Medulla
Cortex
Pelvis
Role of cortex
The cortex is the dark outer layer. This is where the filtering of the blood takes place and it has a very dense capillary network carrying the blood from the renal artery to the nephrons
Role of the medulla
Lighter in colour- it contains the tubules of the nephrons that form the pyramids of the kidney and collecting ducts
Pelvis function
Central chamber where the urine collects before passing out down the ureter
Structure of the nephron
Bowmans capsule Proximal convoluted tubule Loop of henle Distal convoluted tubule Collecting duct
Structure of bowmans capsule
Cup shaped structure that contains the glomerulus, a tangle of capillaries. More blood goes into the glomerulis than what leaves it due to ultrafiltration
Structure of proximal convulated tubule
The first, foiled region of the tubule after the bowmans capsule, found in the cortex of the kidney. This is where many substances needed by the blood are reabsorbed
Structure of loop of henle
A long loop of tubule that creates a region with a very high solute concentration in the tissue fluid deep in the medulla. The descending loop runs down from the cortex through the module to a hairpin bend at the bottom of the loop. The ascending limb travels back up through medulla to cortex
Structure of distal convoluted tubule
A second twisted tubule where the fine tuning of water balance of the body takes place. The permeability of walls to water vary in the response to ADH.
Structure of collecting duct
The urine passes down the collecting duct through the medulla to the pelvis. More fine tuning of water balance takes place
Define Ultrafiltration
Removal of nitrogenous waste and osmoregulation of the blood is ultrafiltration.
Define Reabsoprtion
Ultrafiltration removes urea, the waste product of protein breakdown.
What is reabsorbed in The proximal convoluted tubule?
All of glucose, amino acids , vitamins and hormones are moved from the filtrate back into the blood by active transport
Where are podocytes found
Bowmans capsule
