Study Set Content:
- an oily, white substance rich in lipids.
sebum
The sebum is released by
holocrine selection
There are two kinds of sweat glands:
- eccrine and apocrine.
- are simple, coiled, tubular glands and release sweat by merocrine secretion.
Eccrine sweat glands
Eccrine glands are located in almost every part of the skin but most numerous in the
palms and soles
- have ducts that open onto the surface of the skin through sweat pores and are for thermal regulation.
Eccrine sweat glands
- Sweat can also be released in the palms, soles, armpits, and other places because of emotional stress.
- Sweat can also be released in the palms, soles, armpits, and other places because of emotional stress.
- are simple, coiled, tubular glands that produce a thick secretion rich in organic substances.
Apocrine sweat glands
Apocrine sweat glands become active at puberty because of the influence of
sex hormones
Gives body odor
Apocrine sweat glands
is a thin plate, consisting of layers of dead stratum corneum cells that contain a very hard type of keratin.
Nail
The visible part of the nail is the nail body, and the part of the nail covered by skin is the
Nail root
- is stratum corneum that extends onto the nail body and the nail root extends distally form the nail matrix.
eponychium
the nail root extends distally form the
Nail matrix
can be seen through, the nail body as a whitish, crescent-shaped area at the base of the nail
lunula
The integumentary system performs many protective functions:
- Reduction in body water loss
- Acts as a barrier that prevents microorganisms and other foreign substances from entering the body
- Protects underlying structures against abrasion
- Melanin absorbs ultraviolet light and protects underlying structures from its damaging effects
- Hair protection: The hair on the head acts as a heat insulator, eyebrows keep sweat out of the eyes, eyelashes protect the eyes from foreign objects, and hair in the nose and ears prevents the entry of dust and other materials.
- The nails protect the ends of the fingers and toes from damage and can be used in defense.
Receptors in the epidermis and dermis can detect
- pain, heat, cold, and pressure.
Although hair does not have a nerve supply, sensory receptors around the hair follicle can
- detect the movement of a hair.
UV light causes the skin to produce a precursor molecule of
Vitamin d
Vitamin D Production
- UV light causes the skin to produce a precursor molecule of vitamin D.
- The precursor molecule is carried by the blood to the liver where it is enzymatically converted.
- The enzymatically converted molecule is carried by the blood to the kidneys where it is converted again to the active form of vitamin D.
- Vitamin D stimulates the small intestine to absorb calcium and phosphate for many body functions.
