University:
Glendale Community College
Course:
BIO160 | Introduction to Human Anatomy and Physiology
Academic year:

2024
Views:

187

Pages:

4
Author:

ilikemyicons0y5

ACCESSORY ORGANS IN THE INTEGUMENTARY SYSTEM Anatomy and Physiology This document contains lecture notes about the accessory organs in the integumentary system: hair, nails, and glands. INTRODUCTION The integumentary system has accessory structures which include the hair, nails, sweat glands and sebaceous glands. HAIR Hair is produced in the hair bulb. It is found almost everywhere. When new hair begins to grow, it pushes out the old hair resulting to hair fall. PARTS OF THE HAIR: 1. Hair follicle – The hair follicle is where the hair arises; the invagination of the epidermis that extends deep into the dermis 2. Shaf – the part of the hair that we cut. 3. Root – found below the surface. 4. Bulb – expanded base of the root where hair is produced. 5. Cortex – It is the thickest hair layer that contains most of the hair’s pigment, giving the hair its color. 6. Medulla – softer center surrounded by the cortex. 7. Cuticle – single layer of overlapping cells that holds the hair in the hair follicle and covers the cortex. 8. Hair papilla – blood vessels within the papilla that supply the bulb with nutrients to produce hair. PHASES OF HAIR GROWTH 1. Anagen phase – Hair is formed through mitosis wherein new hair is formed and pushes the club hair up the follicle and eventually out. 2. Catagen phase – The transitional stage where growth stops and outer root sheath shrinks and attaches to the root of the hair. 3. Telogen phase – The resting phase where the club hair is completely formed. GLANDS OF THE SKIN There are two glands of the skin: the Sebaceous and Sweat Glands. SEBACEOUS GLANDS Sebaceous glands are simple, branched acinar glands that produce sebum through holocrine secretion. It is an oily white substance rich in lipids that lubricates hair and skin. SWEAT GLANDS There are two types of sweat glands: Eccrine and Apocrine. ECCRINE SWEAT GLANDS Eccrine sweat glands are simple, coiled tubular glands that are located in almost every part of the skin. They release sweat by merocine secretions (exit the cells via exocytosis). They have ducts that open onto the surface of the skin through sweat pores and are for thermal regulation. APOCRINE SWEAT GLANDS Apocrine sweat glands are simple, coiled tubular glands that produce thick secretions rich in organic substances. They open into the hair follicles in the armpit and genitals. They are active during the puberty stage. NAILS The nail is a thin plate composed of layers of dead stratum corneum cells. It contains a hard type of keratin and has no resting stage in growth. PARTS OF THE NAIL 1. Nail body – visible part 2. Nail root – covered by skin 3. Cuticle – stratum corneum that extends onto the nail body 4. Nail matrix – epithelial tissue that is thicker than the nail bed 5. Nail bed – epithelial tissue where nail is attached 6. Lunula – whitish, crescent-shaped area