The Integumentary System (2nd Exam)
Integumentary System
Consists of:
Skin
Hair
Nails
Sweat glands
Sebaceous (oil) glands
Functions:
Protection: a physical and chemical barrier to abrasion, invasion, dehydration, and UV light
Temperature regulation: produces sweat, which reduces body temperature
Stimulus Perception: nerve endings detect touch, temperature, pressure, etc.
Excretion: perspiration serves to eliminate bodily wastes
Synthesis of Vitamin D: conversion of type of cholesterol into vitamin D happens in the epidermis
Blood/water reservoir: the dermis is extensively vascular and stores large volumes of blood until needed
elsewhere
Structure:
The skin consists of two distinct regions:
o Epidermis
Most superficial region
Consists of Keratinized stratified squamous epithelium
, Is avascular (lacking blood vessels)
ALL EPITHELIUM US AVASCULAR
o Dermis
Underlies the epidermis
Thick, fibrous connective tissue layer
Is vascular (contains blood vessels)
The subcutaneous layer just deep to the skin is the Hypodermis (not part of the skin)
o Not considered a part of the skin, but shares some functions
o Also known as the “superficial fascia”
o Made of adipose and areolar tissue
o Acts to anchor the skin to underlying muscles
o Serves as a shock absorber and insulator
o Contains Pacinian corpuscles, which are nerve endings sensitive to pressure changes
Epidermis
Cells of the epidermis:
o 1) Keratinocytes
Produce the fibrous protein Keratin that gives the skin its waterproof, protective properties
Make up most cells of the epidermis
Tightly connected by desmosomes
Surface keratinocytes are dead, and millions fall off every day
o 2) Melanocytes
Located in the deepest epidermis (base layer)
Integumentary System
Consists of:
Skin
Hair
Nails
Sweat glands
Sebaceous (oil) glands
Functions:
Protection: a physical and chemical barrier to abrasion, invasion, dehydration, and UV light
Temperature regulation: produces sweat, which reduces body temperature
Stimulus Perception: nerve endings detect touch, temperature, pressure, etc.
Excretion: perspiration serves to eliminate bodily wastes
Synthesis of Vitamin D: conversion of type of cholesterol into vitamin D happens in the epidermis
Blood/water reservoir: the dermis is extensively vascular and stores large volumes of blood until needed
elsewhere
Structure:
The skin consists of two distinct regions:
o Epidermis
Most superficial region
Consists of Keratinized stratified squamous epithelium
, Is avascular (lacking blood vessels)
ALL EPITHELIUM US AVASCULAR
o Dermis
Underlies the epidermis
Thick, fibrous connective tissue layer
Is vascular (contains blood vessels)
The subcutaneous layer just deep to the skin is the Hypodermis (not part of the skin)
o Not considered a part of the skin, but shares some functions
o Also known as the “superficial fascia”
o Made of adipose and areolar tissue
o Acts to anchor the skin to underlying muscles
o Serves as a shock absorber and insulator
o Contains Pacinian corpuscles, which are nerve endings sensitive to pressure changes
Epidermis
Cells of the epidermis:
o 1) Keratinocytes
Produce the fibrous protein Keratin that gives the skin its waterproof, protective properties
Make up most cells of the epidermis
Tightly connected by desmosomes
Surface keratinocytes are dead, and millions fall off every day
o 2) Melanocytes
Located in the deepest epidermis (base layer)
