Chapter 6: Integumentary System

CCAC Anatomy and Physiology fall 2026

integument

skin

integumentary system includes

skin, nails, hair, sweat/oil glands

what is the largest organ

skin

dermatology

study/ treatment of integumentary system

skin functions

protection

prevents water loss

vit d synthesis

secretion

absorbtion

temp regulation

immuse deffense

sensory reception

layers of the integument

epidermis

dermis

epidermis

superficial layer / keratinized stratified squamous

dermis

deep layer, connective tissue, contains blood vessels, glands, nerves, hair follicles, etc

epidermail layers

basale, spinosum, granulosum, lucidum (thick skin only), corneum

deep to superficial

memory: before signing, get legal counsel

layers of the epidermas - living

basale, spinosum, granulosum

layers of the epidermas - dead

lucidum, corneum

which layer of epidermis:

• single layer of cuboidal -? low columnar cells

• attatched to basement membrane

• contains 3 major cell types (keratinocytes, melanocytes, merkel/tactile cells)

stratum basale

which layer of epidermis:

• several layers of polygonal keratinocytes

• cells connected by desmosomes

• contains epidermal dendritc cells (immune cells)

stratum spinosum

which layer of epidermis:

• 3-5 layers of keratinocytes

• large amounts of keratin

• nucleus and organelles break down and cells die

stratum granulosum

which layer of epidermis:

• only in thick skin (palms and soles of feet

• 2-3 layers of flattened keratinocytes

stratum lucidum

which layer of epidermis:

• 20-30 layers of dead keratinized cells

• lack nuclei and organelles

• provides: physical protection, water barrier, protection

stratum corneum

skin color results from:

hemoglobin and melanin

hemoglobin

found in red blood cells

• vasodilation= more pink/red

• vasoconstriction= paler

melanin

produced by melanocytes

layers of dermis

papillary and reticular layer

papillary layer of dermis

superficial / areolar connective dissue

reticular layer of dermis

deep / dense irregular connective tissue

what does the dermis contain

collagen, elastic fibers, reticular fibers

subcutaneous layer

hypodermis / superficial fascia

composition of the hypodermis

areolar and adipose connective tissue

function of the hypodermis

pads and protects body/ energy storage / thermal insulation / anchors skin

functions of the integument (8)

protection

prevents water loss/gain

vitamin D synthesis

secretions

absorption

temp regulatino

immune function (dendritic cells)

sensory regulation

what is produced by sebaceous glands

sebum (oil)

what is produced by sweat glands

sweat

ways the body maintains temperature regualtion

vasoconstrictinon

vasodilation

sweating

other name for structures derived from the dpidermis

epidermal derivatives and appendages

examples fo structures derived from the epidermis

nails and hair (dead keratinocytes)

glands (living epitheial cells)

what are nails

modified stratum corneum

what are the 3 types of hair

languo

vellus

terminal

type of hair

langugo

mostly replaced before birth

type of hair

vellus

main human body hair

type of hair

terminal

coarser longer pigmented hair

layers of the hair

medulla

cortex

cuticle

structures of hair

hair bulb

root

shaft

functions of hair

protection

heat retention

sensory reception

visual identification

hair growth cycle

1. anagen = active growth (18m→7years)

2. catagen = regression (3-4weeks)

3. telogen = resting (3-4 months)

how much is normal hair loss per day

10-100 hairs per day

exocrine glands

sweat glands

sebaceous glands

specalized integumentary glands

2 major sweat gland types

merocrine (eccrine) sweat glands

apocrine sweat glands

merocrine (eccrine) sweat glands

secreate directly into skin surface

main function: thermoregulation

apocrine glands

bacteria break down secretion → body odor

contains: proteins and lipids

sebaceous glands (holocrine glands)

produces sebum

functions: lubricates skin/hair, make skin water resistant, bactericidal properties

ceruminous glands

modified aprocrine sweat glands

produce cerumen (earwax)

mammary glands

modified aprocrine sweat glands

produce breast milk

repair of the integument process

repeated mechanical stress → increase stem cell division → thicker epidermis

regeneration

damaged cells replaced by the same cell type

can restore normal tissue function

fibrosis

damaged area replaced with scar tissue

collagen fibers produced by fibroblasts

restore structure partially; does not restore full function

steps of found healing

1. blodo clot

2. clot forms

3. granulation tissue

4. regeneration / fibrosis

development (germ layers)

ectoderm → epidermis

mesoderm → dermis

epidermal cells (4)

keratinocyte

melanocyte

merkel cell

dendrict /langerhans

epidermal cell main function

keratinocyte

keratin; strength and water resistance

epidermal cell main function

melanocyte

melanin; UV protection

epidermal cell main function

merkel cell

touch

epidermal cell main function

dendritic / langerhans

immune defense