Download The Integumentary System

The Integumentary System
Chapter 4
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Introduction
– Structure
• Epidermis
• Dermis
• Hypodermis
– Functions of the skin
Human Anatomy, 3rd edition
Prentice Hall, © 2001
The “Birthday Suit”
– Combination of 4 main tissues
• Epithelial – outer layer
• Connective – underlies dermis
• Smooth Muscle – goose bumps
• Nervous – sensory receptors
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Functions of the Skin
–
–
–
–
–
–
–
Protection
Temperature regulation
Sensations
Storage of chemical compounds
Excretion of wastes
Synthesis of compounds
Determines characteristics
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Structure of the Skin
– 2 principal parts
• Epidermis
• Dermis
– Beneath the dermis
• Subcutaneous layer
Human Anatomy, 3rd edition
Prentice Hall, © 2001
The Skin
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Epidermis
– Stratified squamous epithelium
– Over most of the body it’s thin
– Approximately every month we shed entire skin surface
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Epidermis
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Epidermis
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Replacement of Epidermal Cells
– Base of epidermis
• Cuboidal cells divide by mitosis
• New cells are pushed toward surface
–
–
–
–
New epidermal cells produce keratin
Cells are flattened as they are pushed upwards
Cells die
Outermost layer
• Cells are dead, filled with keratin
– Takes about two weeks for an epidermal cell to
move from the bottom layer to the top
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Pigments
– Melanin
• Produced by melanocytes
• Skin color varies
• Protect skin from UV rays
– Carotene
– Albino
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Melanocytes and Melanin
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Melanocytes and Melanin
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Epidermis and Dermis
–
–
–
–
Epidermis is avascular
Dermis is highly vascular
Epidermis receives nourishment from dermis
Cells far away from nourishment die
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Dermis
– Largest part of the skin
– Connective tissue
– Contains
• Blood vessels
• Nerves
• Glands
• Hair follicles
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Papillary Layer of the Dermis
– Most superficial layer
– Surface area increased by papillae
• Form fingerprints
– Has lots of sensory receptors Papillary
Layer
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Papillary Layer
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Fingerprints
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Deeper Layer of the Dermis
– Deeper layer
– Dense connective tissue
– Contains
• Blood vessels
• Glands
• Deep pressure receptors
– Attached to underlying organs by the
subcutaneous layer
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Subcutaneous Layer
– Loose connective tissue
• Packed with adipose cells
– Stabilizes position of skin
Human Anatomy, 3rd edition
Prentice Hall, © 2001
The Skin
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Epidermal Derivatives
– Hair
– Glands
– Nails
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Functions of Hair
–
–
–
–
Protection
Thermoregulation
Sensory
Minor role in humans
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Hair Structure
– Shaft
• Superficial portion
– Root
• Below the surface
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Hair Structure
– Medulla
• Soft core of hair
– Cortex
• Hard core that gives hair its stiffness
– Cuticle
• Outermost layer of hair
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Hair Structure
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Hair Structure
– Hair develops in follicles
• Downward continuation of epidermis
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Growth of Hair
– At the base of the follicle, hair papilla
• Contains blood vessels and nerves
– Nourishes hair
– Bulb
• Contains matrix – epithelial cells responsible for
growth
– Contains melanocytes
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Hair Follicle
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Arrector Pili
–
–
–
–
Smooth muscle attaches to follicle
Raises hairs
Response to fright or cold
Function?
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Glands
– Sebaceous glands
• Connected to hair follicles
• Secrete a waxy, oily substance (sebum)
– Blackheads
• Secretion increases at puberty
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Sebaceous Glands
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Glands
– Sweat glands
• Found just about everywhere
• Produce “perspiration”
– Water, salt, met. Wastes
• Function – cooling of the body
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Glands
– Scent Glands
• Specific type of sweat gland
• Found near hair follicles
– Axillary & genital regions
• Develop at puberty
Human Anatomy, 3rd edition
Prentice Hall, © 2001
The Skin with Sweat Glands
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Nails
– Dorsal surfaces of ends of fingers & toes
– Primate feature
– Grasping
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Nail Structure
– Nail body
– Free edge
– Nail root
• Matrix
– Lunula (moon)
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Nail Structure
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Skin Cancer
– Basal Cell Carcinoma
– Squamous Cell Carcinoma
– Melanoma
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Basal Cell Carcinoma
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Squamous Cell Carcinoma
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Melanoma
Human Anatomy, 3rd edition
Prentice Hall, © 2001