Lecture 16 - accessory structures and functions

structure of hair

• above epidermis = non-living, keratinized cells

• below epidermis = living hair follicle + bulb

locations of hair

• covered almost entirely with vellus hairs

• darker, thicker hair = terminal hair

• thick skin and mucosal regions lack hair

functions of hair

• sensation (not the hair itself!)

• thermoregulation

• protection

• social/cultural significance

1-4

1. hair follicle/bulb

2. arrector pilli

3. hair shaft

4. sebaceous gland

hair growth cycle phases

• anagen phase

• catagen phase

• telogen phase

description of anagen phase

• 2-7 years

• rapid cell division in hair matrix

description of catagen phase

• 2-3 weeks

• transition into quiescence

• lose some diameter

description of telogen phase

• weeks to ~ 1 year

• “resting “, shedding

• ~10-15% in telogen at once

• ends with restart of anagen

function of nails

• protection

• dexterity

• sensation

• many cutaneous and systemic diseases cause changes to the nails

nail anatomy

what is an exocrine gland?

• a gland that makes something and secretes it to a body surface

what are the exocrine glands of integumentary system?

• sweat glands

• sebaceous glands

• ceruminous glands

• mammary glands

What are sweat glands? function and types and structure

• AKA sudoriferous glands

• function → primarily theroregulatory

• types

  • eccrine

  • apocrine

  • apoeccrine

• structure

  • cuboidal or columnar epithelial cells

Eccrine sweat glands

• 2-4 million

• function soon after birth

• form until ~2-3 years old

• fluctuates with weight and age

• glabrous (palms/soles & DENSE) vs. non-glabrous (other/hairy & decreased density)

• mainly H20/NaCl

Apocrine

• armpits and anogenital region

• functional around puberty

• larger, associated with hair follicles

• ammonia, lipids, sugars, proteins

What is the mechanism for secretion for sweat glands?

• merocrine secretion

  • nucleus

  • golgi complex

  • secretory vesicles

  • secretion

• exocytosis