Sweat Glands Lecture Notes

Overview

Sweat glands, also known as cerous glands, are present on all skin surfaces except nipples and external genitalia.
There are approximately 3 million sweat glands per person.
Two major types of sweat glands: Eccrine and Apocrine.

Also known as merocrine sweat glands.
Most numerous, found on palms, soles of feet, and forehead.
Ducts connect to pores on the skin surface.
Primarily involved in thermoregulation through evaporative cooling.
Controlled by the sympathetic nervous system (fight or flight response).
Sweat secretion:
- Mostly water.
- Contains salts, vitamin C, antibodies, dermcidin (microbe-killing peptide), and metabolic wastes.
- In cases of renal failure, may secrete urea, causing "ureic frost."
Structure:
- Tubular, highly coiled glands embedded in the dermis.
- Drains through ducts to skin surface.
- Myoepithelial cells aid in pushing sweat to the surface.

Located in axillary (armpit) and anogenital areas.
Secretes a viscous, milky/yellowish sweat containing fatty substances and proteins.
Becomes active during puberty.
Potentially acts as a sexual scent gland; could be involved in pheromonal communication.
Bacterial breakdown of apocrine secretions causes body odor.
Structure:
- Larger than eccrine glands.
- Ducts empty into hair follicles, not directly onto the skin.
Not involved in thermoregulation.

Ceruminous Glands:
- Found in the external ear canal.
- Secretes cerumen (ear wax).
Mammary Glands:
- Modified apocrine glands that produce breast milk.

Associated with hair follicles.
Widely distributed except in the thick skin of palms.
Inactive until puberty, stimulated by hormones (androgens).
Secretes sebum (oil):
- Holocrine secretion (whole cell bursts to release oil).
- Contains bactericidal properties.
- Softens and conditions hair and skin.
Ducts drain onto hair, aiding in conditioning skin and hair.