Integumentary
→ The integumentary system is the skin and is the largest organ in the body.
FUNCTIONS:
→ Protection: → The cells of the skin undergo keratinisation in order to act as a physical barrier against injury and environmental factors.
↳ The skin helps protect against dehydration and absorption of large quantities of water.
→ The melanocytes in the skin produce pigment to protect the underlying structures from the harmful effects of UV radiation.
↳ The skin provides a flexible cover, and acts as a padding to protect underlying organs.
→ Temperature regulation: → Body temperature should be maintained at 36.7°C. The skin helps maintain a constant body temperature by:
↳ Glands that produce sweat which cools rapidly on reaching the skin surface.
↳ Superficial capillary dight in order to increase the supply of blood to the surface of the body; This allows for heat loss.
↳ Contraction of the capillaries causes of blood to return to the internal tissues before it has a chance to cool.
→ Absorption: → This function is limited, but substances that can be absorbed include:
↳ Some drugs in transdermal patches, hormone, replacements, nicotine, patches or creams.
↳ Some toxic chemicals, e.g. mercury.
→ Vitamin D production: → When exposed to UV light, the skin produces cholecalciferol which is modified in the liver, & then the kidneys to form active vitamin D.
→ Vitamin D increases blood calcium levels by:
↳ Promoting calcium uptake from the intestine.
↳ Release of calcium from bone.
↳ Reduction of calcium loss from the kidneys.
→ Sensation: → The skin contains nerve endings, which are receptive to:
↳ Heat.
↳ Cold.
↳ Pressure.
↳ Pain.
↳ Touch.
→ Excretion: → The skin secrets substances in order to carry out specific functions:
↳ Sebum is secreted in order to nourish skin & hair and prevent dehydration.
↳ Sweat is secreted in order to maintain body temperature.
→ Sweat & sebum combine to form the acid mantle (pH 4.5-6), to protect against infection.
STRUCTURES:
→ Hair. → Blood vessels.
→ Nails. → Lymph vessels.
→ Sweat glands. → Nerves.
→ Oil glands. → Muscles.
→ The integumentary system is the skin and is the largest organ in the body.
FUNCTIONS:
→ Protection: → The cells of the skin undergo keratinisation in order to act as a physical barrier against injury and environmental factors.
↳ The skin helps protect against dehydration and absorption of large quantities of water.
→ The melanocytes in the skin produce pigment to protect the underlying structures from the harmful effects of UV radiation.
↳ The skin provides a flexible cover, and acts as a padding to protect underlying organs.
→ Temperature regulation: → Body temperature should be maintained at 36.7°C. The skin helps maintain a constant body temperature by:
↳ Glands that produce sweat which cools rapidly on reaching the skin surface.
↳ Superficial capillary dight in order to increase the supply of blood to the surface of the body; This allows for heat loss.
↳ Contraction of the capillaries causes of blood to return to the internal tissues before it has a chance to cool.
→ Absorption: → This function is limited, but substances that can be absorbed include:
↳ Some drugs in transdermal patches, hormone, replacements, nicotine, patches or creams.
↳ Some toxic chemicals, e.g. mercury.
→ Vitamin D production: → When exposed to UV light, the skin produces cholecalciferol which is modified in the liver, & then the kidneys to form active vitamin D.
→ Vitamin D increases blood calcium levels by:
↳ Promoting calcium uptake from the intestine.
↳ Release of calcium from bone.
↳ Reduction of calcium loss from the kidneys.
→ Sensation: → The skin contains nerve endings, which are receptive to:
↳ Heat.
↳ Cold.
↳ Pressure.
↳ Pain.
↳ Touch.
→ Excretion: → The skin secrets substances in order to carry out specific functions:
↳ Sebum is secreted in order to nourish skin & hair and prevent dehydration.
↳ Sweat is secreted in order to maintain body temperature.
→ Sweat & sebum combine to form the acid mantle (pH 4.5-6), to protect against infection.
STRUCTURES:
→ Hair. → Blood vessels.
→ Nails. → Lymph vessels.
→ Sweat glands. → Nerves.
→ Oil glands. → Muscles.
