Excretory System Flashcards
How are N-wastes formed?
Nitrogenous wastes form from the breakdown of proteins when N-part splits off the amino acids when converting to carbs or lipids.
What do N-wastes produce?
N-wastes produce ammonia which is a highly toxic very soluble molecule which diffused across cell membranes. It also produces urea which is a large molecule but less toxic and highly soluble in water. Along with this Uric Acid is produced, which is highly insoluble and relatively non-toxic and requires twice the energy to produce than urea from ammonia.
What is the function of the mammalian kidney?
The functions of the mammalian kidney are carried out by the nephron. It is responsible for regulating the salt and water concentrations and removing and excreting metabolic wastes that exit the body as urine.
What is the structure of a nephron?
A nephron is composed of a Bowmans capsule surrounding a glomerulus and a tubular region which leads into a collecting tube and a loop of Henle.
What is the function of a nephron?
Filtration, re-absorption and secretion
What is filtration?
High blood pressure of blood in glomerulus whereby blood vessels force fluid through the walls of the capillaries into capsule. Small molecules and water only get through and cells and large plasma proteins stay in capillaries.
What is reabsorption?
Glucose and amino acides are reabsorbed by active transport along the convoluted tubule and water passively moves by osmosis
What is secretion ?
Active transport of H and K from blood to filtrate in distal tubule.
What is the loop of Henle?
variable permeability for salt and water and has a salt gradient used for osmotic withdrawal of water from collecting duct.
