Excretion Flashcards
What is excretion?
The elimination of metabolic waste produced by the body
What are the 3 excretory organs?
Lungs (CO2 and H2O vapour)
Skin (sweat (salt H2O))
Kidneys (Urine (salt, H2O and urea))
What is the outer layer of the skin known as?
Epidermis (cornified (dead) , granular (keratin), malpigphian (melanin))
What is the second layer of the skin called?
Dermis
What is the name of the layer of skin where fat is stored?
Adipose tissue
How does the skin function for protection?
Physical barrier (epidermis) against pathogens
Melanin produced in malpigphian layer protects against UV
Sebum released from sebaceous gland protects against pathogens
Why does the skin produce vitamin D?
Helps calcium in bones to be absorbed
How does the skin function for excretion?
Sweat glands produce sweat (salt and water) and is released through sweat pores.
How does the skin store fat?
Fat is located in adipose tissue and has an insulating effect.
How does the skin regulate temperature?
Cold:
Hair erector muscle contracts.
Hair follicles stand up (piloerection).
Hairs trap air insulating the body.
Blood vessels (arterioles) constrict, called vaso-constriction and lie deep holding in heat into the body. Brain causes body to shiver to generate heat.
Hot:
Hair erector muscles relax, hairs lie flat.
Blood vessels (arterioles) widen/ open called vasodilation.
Heat is lost from the body, turning red.
Sweating occurs as heat evaporates sweat causing a cooling effect
What is the function of the kidneys?
Filter blood (salt, water, urea)
What is the function of the renal veins?
Carries filtered blood away from the kidneys
What is the function of the renal artery?
Carries blood to kidney
What is the function of the cortex?
Filtration
What is the function of the medulla?
Reabsorption