Glands in the Skin

Where ?

Sebaceous glands are located over most of the surface of the skin/body but not in the palms of the hands or the soles of the feet.

Secretion(s):

Sebaceous glands secret an oily substance called sebum.

Why ? Good:

Sebum helps to protect skin and hair by:

• preventing hairs from becoming too dry and brittle
• preventing the skin from becoming too dry (by preventing excessive evaporation of water from the surface of the skin), hence also helping to keep the skin soft and effective
• restricting the growth/development of certain bacteria.

Also note:

The activity of sebaceous glands increases during and sometimes beyond teenage years (adolescence). Over-active sebaceous glands can result in the accumulation of sebum in the glands and/or pores, causing the affected glands to become enlarged and the appearance of blackheads and other disturances to the skin, commonly around on the face.

Different Types:

• Apocrine Glands - ducts open in hair follicles
• Eccrine Glands - ducts terminate at a sweat pore at the outer surface of the epidermis

Where ?

Apocrine Glands :-

Eccrine Glands :-

• Armpits (skin of the axillae)
• Pubic region
• Pigmented areas of breasts (areolae)

• Throughout the skin
  (except for margins of lips, eardrums, nailbeds of finger and toe nails)

Secretion(s):

Sudoriferous glands secret sweat, which is also called 'perspiration'. Apocrine glands secret a sticky viscous secretion while the secretion from eccrine glands is thinner; watery by comparison.

Why ? Good:

The main functions of the secretion of sweat are to help regulate body temperature and to help eliminate from the body some of the waste products of metabolism (i.e. metabolic reactions).

Also note:

Mammary glands (female breasts) are modified sudoriferous glands that produce breast milk.

Ducts open either directly onto the surface of the external auditory canal or into the ducts of sebaceous glands.

Where ?

The external auditory canal, also known (colloquially) as simply the 'outer ear'.

Secretion(s):

The prefix 'cer-' means 'wax'.
The secretions from ceruminous glands combines with sebum secreted by nearby or associated sebaceous glands to form cerumen which is also known colloquially as 'ear wax'.

Why ? Good:

Cerumen, assisted by the hairs in the outer ear, protects the ear from particles originating outside of the body e.g. of dust, fine sand, or similar in the air getting into the ear itself. Cerumen provides a sticky barrier that prevents many such particles from going further into the ear.

Also note:

In some cases the body produces excessive amounts of cerumen. This can then accumulate, harden and compact, reducing the effectiveness of sound waves reaching the ear drum and therefore adversely affecting hearing. People affected by excessive ear wax are warned against putting - neven soft - objects into the ear to dislodge the ear wax because this can cause further problems e.g. if compacted cerumen is unintentionally pushed further into the ear, or other objects such as cotton buds detach and also get stuck in the ear.