Excretion Flashcards
Excretion
The removal of the waste products of metabolism
Metabolism
Describes all the chemical reactions that take place in living organisms
Kidney excretes
Urine (Water,urea&salt) to remove harmful urea and control water content of the body
Lungs excretes
Carbon dioxide and water to remove waste products produced by respiring cells
Skin excretes
Sweat (Water, salts and small amounts of urea) to cools the body
Urine is comprised of
Urea
Salts
Water
Renal artery
Lots of oxygen glucose water salts urea
Renal vein
Less oxygen & glucose (some is respired)
Less urea (removed in urine)
Right amount of water and salt (excess is removed in the urine)
Excretion
The removal of the waste products of metabolism.
Urine is the product of
Deamination (The break down of excess amino acids) in the liver.
Ureter
Transports urine from the kidney to the bladder
Urethra
Transports urine out of the body
Urea
Produced from the breakdown (deamination) of excess amino acids in the liver
urine
A solution of urea + water + salts, stored in the bladder before being released from the body.
Nephron
Functional filtering unit of the kidney, also known as kidney tubules, Each kidney contains about a million of these units.
Bowmans capsule
Hollow cup of cells surrounding the glomerulus.
Glomerulus
A dense network of capillaries where water, ions, glucose and urea are filtered from the blood into the tubules
Glomerular filtrate
The fluid forced out of the glomerulus under high pressure. It contains water, glucose, urea, ions and other small molecules, but not blood cells and lard molecules such as proteins.
Proximal convoluted tubule
Site where the majority of the glomerular filtrate is reabsorbed. All of the glucose is reabsorbed back into the blood here by active transport.
Loop of Henle
A U-shaped loop that runs down into the medulla of the kidney. It has a complicated role in concentrating the fluid in the tubule to allow more water to be reabsorbed into the blood.
Collecting duct
The tubule that receives urine form numerous nephrons. The permeability of its wall to water is controlled by ADH
Ultrafiltration
The process where fluid (called glomerular filtrate) is forced out of the glomerulus under high pressure.
(First coiled tubule) Selectively reabsorption
The process where the substances we need, e.g. glucose, are reabsorbed from the tubules back into the blood stream
Active transport
The transport of a substance across a biological membrane against a concentration gradient. Energy from respiration is required
