Chapter 31: Excretion Flashcards
Describe plant excretion.
Give off little waste
Store some and lose most waste when dead structures fall off
Lose waste gases through stomata and lenticels
What are the three layers of skin?
Epidermis
Dermis
Adipose tissue/subcutaneous tissue
There are 3 layers within the epidermis what are they?
Cornfield layer
Granular layer
Malpighian layer
Describe the cornfield layer.
Keratin build up causes the cell to become hardened
Lack of blood capillaries
This causes the Cells to die and flake off
Describe the granular layer.
Cells push through this layer and make protein called keratin
Describe the malpighian layer.
New cells are made here by mitosis.
Specialized cells make melanin which gives the skin colour and protects against us rays
Describe the dermis.
Made of connective tissue with the protein collagen for strength.
Contains sweat glands, hair follicles, blood vessels, nerve receptors, sebaceous glands
What are sebaceous glands?
They produce oil called sebum
What is adipose tissue?
Fat acts as a food store
What happens to skin in cold conditions?
Erector muscle contracts to form goose bumps
Causes hair to stand up in a reaction called pilorection
A layer of warm air is trapped between the hairs.
Blood vessels contract which reduces heat loss - vasoconstriction
What muscle forms goose bump?
Erector muscle
What process causes hairs to stand up?
Pilorection
What process causes blood vessels to contract?
Vasoconstriction
What happens to skin in warm conditions?
Sweat produced by sweat glands - evaporation of water lowers body temp
Blood vessels dilate - increase heat loss through skin
What are 5 other functions of skin?
Protection Vitamin production Food store Sense organ Excretion
Give 4 examples of how skin protects us.
Epidermis - water loss and entry of pathogens
Dermis - protects internal organs
Melanin - from uv rays
Sebum - prevents skin from drying up
What vitamin is made in skin?
Vitamin d
What is excretion?
Removal of waste products of metabolism from the body
What is egestion?
Removal of undigested unabsorbed material from the digestive system
What are the 4 roles of the excretory system in homeostasis?
- Regulates body temp
- Osmoregulation
- Controls concentration of fluids
- Removes waste
What are the three organs of excretion and the waste products they make?
Lungs - water and carbon dioxide
Skin - water and salt
Kidneys - water salt and urea
What is urea made from and where?
Liver - deamination of amino acids