Anatomy and Physiology: Chapter 3 The Skin

cover surface, line body cavities and form protective surfaces around organs

body membranes

2 types of body membranes

1. epithelial membranes

2. connective tissue membranes

epithelial membranes primarily

cover and line body parts

all epithelial membranes contain ____ tissue with underlying layer of ____ tissue 

epithelial, connective

skin

cutaneous membranes

dry membrane, exposed to air

cutaneous membranes

cutaneous membranes 

______ ______ _____ over ____ _____ _____

stratified squamous epithelium, fibrous connective tissue 

line body cavities open to the exterior

mucous membranes

organs of respiratory, digestive, urinary, and reproductive tracts

mucous membranes

continuously bathed in mucous

mucous membranes

mucous membranes

_______ over _____ _____ _____

epithelium, loose connective tissue

line body cavities closed to the exterior 

serous membranes 

walls of ventral body cavity, outer covering of organs

serous membranes

_____ ____ _____ over ____ ____ ____

simple squamous epithelium, areolar connective tissue

2 layers of serous membranes

parietal and visceral 

outermost layer of serous membranes

parietal layer

hugs the organ in serous membranes

visceral layer

clear fluid separating the layers in serous membranes 

serous fluid 

3 types of serous membranes

peritoneum

pleura

pericardium

lines abdominal cavity and covers abdominal organs

peritoneum

surrounds the lungs 

pleura 

surrounds the heart

pericardium

connective tissue membranes are formed solely of

connective tissue

connective tissue membranes 

hold organs in place and line movable joints 

lines capsules surrounding joints, provide smooth surface and cushioning between moving bones

synovial membranes

synovial membranes are made of ____ _____ _____ and produce ___ _____

soft areolar connective tissue, synovial fluid 

composed of skin, hair, nails, and sweat and oil glands

integumentary system

functions of integumentary system

• insulation

• cushion and protect deeper organs

• chemical damage from acids and bases

• thermal damage from extreme heat and cold

• UV damage

• bacteria

• mechanical damage from bumps and cuts

skin is made of what two types of tissue

epidermis and dermis

outermost layers of the skin, made of stratified squamous epithelium 

epidermis 

how many layers are in the epidermis

5

does the epidermis have a blood supply

no, it gets its nutrients from diffusion from the dermis

fibrous protein incorporated into epithelial cells, makes the epidermis tough and water proof 

keratin

cells that produce keratin

keratinocytes

layers if epidermis from bottom to top

stratum basale

stratum spinosum

stratum granulosum

stratum lucidum

stratum corneum

deepest layer, connected to dermis, contains actively dividing cells

• millions of cells produced daily

• new cells are pushed ______

• receive nutrients from _____

stratum basale, upwards, dermis

contains living cells with thick bundles of filaments and keratin

stratum spinosum

contains cells that are flattened with deteriorating organelles

• many are

stratum granulosum, dead

clear layer not present in all skin regions, protection and extra waterproofing

• palms, of hands, fingers, and soles of feet

• all _____ cells

stratum lucidum, dead 

flattened membranes filled with keratin

• all _____ cells

• __ to _ cell layers thick

• accounts for _____ of thickness of epidermis'

• protects ____ _____

• replaced ____ as it flakes off

stratum corneum, dead, 20 to 30, deeper layers, daily

special immune cells scattered throughout the epidermis, activate the immune system to threats such as bacterial or viral invasion, live close to the bottom because of blood supply

epidermal dendritic cells

pigment that ranges from yellow to brown to black that function to protect the DNA in skin cells

melanin

cells that produce melanin, reside in the stratum basale 

melanocytes 

melanin

• simulated by _____

• taken up by ________ and transferred to ______ _____

• forms umbrella on top of cells to cover ______

sunlight, keratinocytes, skin cells, nucleus

layer of connective tissue deep to the epidermis

dermis

dermis

• consists of ___ major regions

• varies in ______ 

• mostly ____ and _____ ____

• rich ______ supply

• abundance of ____ ____ that help with ____ -

two, thickness, collagen, elastic fibers, nerve supply, blood vessels, temperature regulation 

2 layers of dermis

papillary layer, reticular layer

upper dermal region

papillary layer

projections that cause indentations in the epidermis above 

dermal papillae 

deepest skin layer

reticular layer

reticular layer

• contains _____ _____, ____ ____, and ___ _____, and _________ to stop the spread of bacteria

blood vessels, sweat glands, oil glands, phagocytes

adipose tissue, anchors skin to underlying organs, not part of skin 

subcutaneous tissue, hypodermis

hypodermis 3 functions

1. shock absorption

2. fat storage

3. insulation from extreme temperature changes

receptor cells that respond to light touch, shapes, and edges

• found in stratum basale

• connected to sensory nerves 

merkel cells 

receptor cells that respond to pressure

• found throughout the skin, mainly in dermal papillae just under epidermis 

meissner corpuscle 

receptor cells that respond to sustained pressure and skin stretch

• found between dermal papillae and hypodermis

ruffini corpuscle

receptor cells that respond

• found in hypodermis

pacinian corpuscle

receptor cells that respond to temperature 

• found throughout skin

thermoreceptors 

sensory neurons that detect pain

• found throughout skin

nociceptors

accessory structures that arise from the epidermis

skin appendages

each skin appendages has a unique role in 

maintaining homeostasis 

glands that release secretions to the surface of the skin by ducts 

exocrine glands 

exocrine glands

develop as outgrowths of ______

formed by cells of _______ ______

extend deep into and reside almost entirely in ____

epidermis, stratum basale, dermis

glands that empty secretions into hair follicles or directly to skin surface

sabaceous glands 

sabaceous glands

found all over the skin except _______ and ______ because it ______

palms of hands, soles of feet, it takes away grip

oily substance and cell fragments

sebum

sebum

• keeps the skin ____

• prevents hair from becoming ______

• chemicals that ____ ____

soft, brittle, kill bacteria

glands that produce sweat

sweat glands

over ______ sweat glands per person

2.5 million

2 kinds of sweat glands

eccrine glands

apocrine glands

empty sweat directly to surface of skin, found all over body

eccrine glands 

larger, empty secretions into hair follicles, found in areas abundant with hair follicles like scale and armpits

apocrine glands

clear secretion primarily made of water, salts, and metabolic waste

sweat

how does sweat regulate body temperature 

• thermoreceptors sense heat

• glands produce sweat

• sweat evaporates and carries body heat away

thread like flexible epithelial structure made of keratin and dead keratinized cells

hair

fastest growing tissue in the body is 

hair

functions hair provides (2)

insulation

protective functions- nose hair, eyelashes

tube like structure that produces and maintains hair growth

hair follicle

how many hair follicles does the average person have

5 million

smooth muscle attached to hair follicle, contraction pulls hair upright

arrector pili

is arrector pili voluntary or involuntary

involuntary

non-living keratinized, scale like modification of the epidermis

nails

where is the root of the nail 

embedded in the skin

injuries that produce breaks in the skin and expose the body to external environments

open wounds

open wounds run the risk of

infection

results from scraping the epithelium, may cause slight bleeding

abrasions 

linear cut caused by sharp objects, may be severe and require stitches

ex) paper cut, surgery cut

incision

jagged, irregular tear produced by solid impact by an irregular object, may cause extensive tissue damage

lacerations

a pierce to the skin, may have little bleeding, serious risk of infection if not treated properly

punctures 

chunks of tissue torn away by a brute force, serious internal damage may occur

avulsion

injury of internal tissue, epithelium stays intact

closed wounds

bruise, bleeding in the dermis, blood collects in underlying tissue

contusion 

5 causes of infections/allergies

1. viral

2. bacterial

3. fungal

4. parasitic

5. autoimmune

3 types of bacterial infections

1. boils

2. impetigo

3. cellulitis 

• usually caused by staph,

• causes inflammation of hair follicles and sebaceous glands

boils

• highly contagious staph or strep infection

• common in children

• causes pink raised lesions on face and legs

• lesions can rupture

impetigo

• very painful secondary skin infection caused by staph or strep 

• affects dermis and underlying tissue

• usually occurs after cuts, surgery, insect bites

• can spread to other body parts

cellulitis 

3 types of viral infections

1. chicken pox

2. shingles

3. hand foot mouth

• caused by varicella virus

• causes blister like rash

• highly contagious

• stays in body permanently

chicken pox

• reactivation of varicella

• common in adults who had chicken pox

• affects skin and nerves

• extremely painful

shingles