Excretion Flashcards
(22 cards)
Excretion
The removal of metabolic waste from the body
Homeostasis
The maintenance of a constant internal environment in an organism
Ectotherms
Gain or lose heat from or to their external environment
Eg. Frogs, snakes , fish
Endotherms
Generate their own heat from metabolic reactions.
Eg . Humans , dogs
Role of excretory system in homeostasis
- regulating body temp
- controls osmosis
- controls concentration of body fluids
- removes waste products of body
Organs of excretion
Lungs - water + CO2
Skin - water + salts
Kidneys - water, salts , urea
Urinary system
2 kidneys , 2 ureters, the bladder and the urethra
Functions of the kidney
- excretion
- osmoregulation
- pH control
Filtration in kidney
Incoming blood is filtered in the outer cortex
Reabsorption in kidney
Useful materials are then taken back into the blood in the cortex and medulla
Secretion in kidney
Substances are secretes from blood into the cortex
Nephrons
Carry out functions of kidneys.
Located in cortex and medulla of the kidney
Where does filtration take place?
Glomerulus
Ultra-filtration
Filtration in the Bowman Capsule as there is high pressure
Epidermis
Outer layer of skin
Melanin
Specialised cells created in malphigian layer. Protects skin against UV radiation
Malphigian layer
Pigments skin, hair and colour of eyes
Dermis
Inner layer of skin , contains strong protein called collagen
Subcutaneous layer
Contains fat in adipose tissues
Functions of the skin
Protection Vitamin production - D Food store - fat Sense organ Excretion - sweat Temperature regulation
ADH
Anti diuretic hormone.
Volume of urine produced is controlled by this hormone
Where is ADH produced
Hypothalamus
Stored + released from pituitary gland
