13. excretion and homeostasis Flashcards
excretion
the removal of the waste products of metabolism and substances in excess of requirements
urea
a waste product produced in the liver from the breakdown of excess amino acids
urine
a solution of urea and other waste materials in water produced by the kidneys
ureter
one of a pair of tubes that carries urine from the kidneys to the bladder
urethra
the tube that carries urine from the bladder to the outside
deamination
the removal of the nitrogen - containing part of amino acids to form urea
cortex
tissue making up the outer layer in a kidney
medulla
tissue making up the inner layers in a kidney
nephron
one of the thousands of microscopic tubes inside a kidney
glomeruli (singular : glomerulus)
a little network of blood capillaries where blood is filtered in a kidney
reabsorption
in a kidney nephron taking back required substances into the blood
homeostasis
the maintenance of a constant internal environment
insulin
hormone secreted by the pancreas which decreases blood glucose concentration
glucagon
hormone secreted y the pancreas which increases blood glucose concentration
set point
the normal value or range of values for a particular parameter
negative feedback
a mechanism that detects a move away from the set point and brings about actions that take the value back towards the set point
type 1 diabetes
a condition in which insufficient insulin is secreted by the pancreas sp that blood glucose concentration is not controlled
sweat gland
a structure found in the skin of mammals which secretes a watery fluid onto the skin surface to reduce body temperature
hypothalamus
part of the brain that is involved in the control of body temperature
vasoconstriction
narrowing of arteries caused by the contraction of the muscle in their walls
vasodilation
widening the arterioles cause by the relaxation of the muscle in their walls
