Answer
1. Sebaceous glands are exocrine ( holocrine) glands that are located in the dermis, usually , but not always in association with hair follicles. They are found all over the body with the exception of the palms and soles, and are especially numerous in the skin of head and face.
These glands secrete an oily substance called sebum. Sebum is a mixture of various lipids, proteins, cellular debris, and inorganic salts. This secretion coats and waterproofs ; gives the hair its shininess (sheen), and keeps it from drying out and becoming brittle. The coating of sebum on the skin also serves to limit the loss of fluids by evaporation . In addition, sebum is microbiocidal to some organisms.
Work Step by Step
Sebaceous glands and sebum are implicit in the development a of a skin condition called acne which seems to be precipitated and/ or aggravated by the hormones of puberty.
2. Ceruminous glands are apocrine glands are found only in the external ear canal ( external auditory meatus). They secrete an oily substance that has the following effects/actions : waterproofs the external ear canal; kills bacteria in the ear canal;; spreads a coating over ear canal hairs that helps to exclude foreign particles.
3. Sweat glands are also called suderiferous glands because their secretions can develop an unpleasant odor. They also produce sex pheromones that have the function of attracting members of a species (not only humans) of opposite sexes for the purpose of mating.
There are two kind of sweat glands --apocrine, and merocrine: :
a. Merocrine sweat glands are found all over the body but are especially numerous in the skin of the palms and soles. ;
The function to secrete sweat which cools the body when it evaporates; in addition merocrine sweat glands secreates wastes in
in a manner similar to the excretory actions of the kidneys
b. Apocrine sweat glands tend to localize in the pubic area, the axillary areas and in area with facial hair ( in males). Apocrine sweat glands secrete sex pheromones that attract members of the opposite sex.
