Excretion Flashcards
What is excretion?
Getting rid of waste products of metabolism
Homeostasis
Is the internal environment in an organism
Ectotherms
Animals that obtain heat from external sources
Endotherms
Generate heat from their own bodies reactions
Skin is composed of what?
Epidermis and dermis
What is epidermis?
Makes new cells and contains melanin.
What is dermis ?
Contains a strong protein called collagen.
Has many blood vessels, sweat glands, hairs, sebaceous glands and nerve receptors.
Functions of skin:
Protection
Epidermis protects against damage, water loss & entry of pathogens.
Melanin protects against ultraviolet radiation.
Functions of skin:
Vitamin production
Vitamin D is made
Functions of skin:
Food storage
Fat stores energy
Functions of skin:
Sense organ
The skin senses touch, pain and tempature
Functions of skin:
Excretion
Sweat removes water and salts from the body
Funtions of skin:
Cold conditions
Hairs stand up to keep skin warm.
Blood vessels become narrow to retain heat.
Shivering.
Functions if skin:
Warm conditions
Sweating cools the body by evaporation.
Blood vessels widen to lose heat.
What are the main excretory organs?
Lungs ( water & carbon dioxide )
Skin ( water & sats )
Kidneys ( water, salt & urea )
What is the urinary system?
Consits of two kidneys, the bladder & urethra
Where is urine stored ?
In the bladder
Where is urine excreted?
Through the urethra
Functions of kidneys
Excretes water, salts and urea.
Osmoregulation: controls the water content and the salt concentration of the blood.
Where are the nephrons located?
The cortex and medulla
What is the glomerular flitrate?
A dilute solution of waste and useful molecules
Name a hormone?
Anti-diuretic hormone ( ADH )
Where is ADH released?
The pituitary gland
What does ADH control?
The volume of urine
When is ADH realeased?
When plasma has too little water or too much salt
When is ADH not released?
When we drink a lot of water or consume a low salt diet
