The Skin 2.0 Flashcards
What are the layers of the skin?
Epidermal layer, Dermal layer, Hypodermis/subcutaneous layer.
What does the Epidermal layer consist of?
Malpighian Layer, Granular layer, Cornified layer.
What is the function of the Malpighian layer?
Cells are constantly dividing by mitosis to produce new cells and special cells produce pigment ‘Melanin’.
What is Melanin?
A brown/black colour made from protein & genetically controlled. It decides skin, hair & iris colour and protects skin from harmful UV rays.
What happens in the Granular layer?
New cells made in the Malpighian layer move through here and produce a waterproof layer called Keratin.
What occurs in the Cornified layer?
Build up of keratin and lack of blood supply causes cells to harden and die, forming a layer of dead skin at the surface.
What structures are found in the Dermal layer?
Sweat gland, Sebaceous gland, Sense organ, Hair follicles, Blood vessels.
What is the function of the Sweat gland?
Secretion of sweat, important for temperature control and excretion of water & salts.
What does the Sebaceous gland secrete?
Sebum, which is oil on the skin that contains chemicals to trap and destroy pathogens.
What is the role of Sense organs in the skin?
Nerve receptors respond to changes in temperature, pain & touch.
What is the function of Hair follicles?
Attach to philoeacter muscle and play an active role in maintaining body temperature.
What is the function of Blood vessels in the skin?
Supply O2, remove CO2, and help with temperature control through vaso-dilation/restriction.
What is located in the Hypodermis layer?
Adipose tissue that stores fat, which can be converted to Vitamin D when sunlight is present.
What are the functions of the skin?
Protection, Vitamin production, Food store, Excretion.
How is temperature controlled in the body in cold conditions?
Philoreaction, Vasoconstriction, Shivering.
What is Philoreaction?
The upright standing of hair on our skin caused by erector muscle contracting, trapping warm air close to the skin.
What is Vasoconstriction?
When blood vessels in the skin contract to reduce heat loss.
What is Shivering?
Muscles contract & relax quickly, generating more internal heat.
What happens in warm conditions?
Sweats and Vasodilation occur to reduce body temperature.
What is the role of Sweating in warm conditions?
Sweat produced lies on skin, and water evaporates from warm skin to reduce temperature.
What is Vasodilation?
Blood vessels expand, expelling heat and causing redness if the person gets too hot.
What is an Endotherm?
Organisms that can generate their own heat and regulate body temperature.
Example: Humans, dogs.
What is an Ectotherm?
An animal dependent on external sources of body heat.
Example: Lizard.
What two human systems does the skin play a role in?
Nervous system and Defence system.
