Chapter 3: Integumentary system

anatomy and physiology

15%

skin accounts for ___ of your body weight

protection, temp regulation, provide sensory info, make vitamin d

functions of integumentary system

skin, hair, nails, sweat and oil glands, sensory receptors

organs in integumentary system

27

how many days does it take for the outer layer of skin to shed and be replaced

1.5

how many pounds of skin cells do u shed each year

dust

all the dead skin cells you shed turn to ______

epidermis, dermis

2 main parts the skin is made of

subcutaneous layer/hypodermis

deep to the dermis but technically not part of the skin

adipose and areolar tissue

subcutaneous layer is made up mostly of ________

attaches skin to inside body parts. insulates and absorbs.

function of hypodermis

stratifies squamous tissue

epidermis is composed of _________

keratinocytes

type of cell is most numerous and gives protection

melanocytes

type of cell that makes melanin, absorbs UV light

langerhans cells

macrophages that help activate our immune system

merkel cells

_________ are found in the deepest part of epidermis.

macrophage

large cell that eats

5

thick epidermal skin is composed of ___ cell layers

stratum corneum

20-30 cell layers thick; overcoat; protects against abrasion and penetration; dead cells

stratum lucidum

layer of epidermis that is only present in thick skin

stratum granulosum

layer of epidermis that is made of thin, flat cells. apoptosis occurs and cells begin to fill with keratin

stratum spinosum

several cell layers thick - prickly layer

stratum basale

deepest layer, single row of cuboidal or columnar keratinocytes. may contain melanocytes and merkel cells; mitosis happens here

avascular

epidermis is _______

vascular

the dermis is ________

dermis

The 2nd, deeper part of the skin. Has collagen and elastic fibers. Lots of fibroblasts. Can stretch and recoil (but too much leaves stretch marks). Has blood vessels, hair, muscle, glands, and nerves

papilary, reticular

2 layers of the dermis

pap-

bumps prefix

papillary layer

(20%) thin, bumpy top layer. Makes epidermis somewhat bumpy too (finger prints) areolar connective tissue

reticular

sebaceous and sudoriferous glands, hair follicles, adipocytes, lots of fibers. dense irregular.

oil glands

sebaceous glands

sweat glands

sudoriferous glands

epidermal ridges

The surface of fingertips, toes, soles, and palms have _________. They are a result of the "bumpy" dermal papillae.

sweat glands

cause u to leave finger prints behind

mechanoreceptors

Touch receptors in our skin are classified as ___________ to provide info to the brain about touch, pressure, vibration, and tension

Meissner's corpuscles

receptors found near the upper dermis

Pacinian corpuscles

receptors found deep in the dermis

pressure

Pacinian corpuscles are _______ receptors

merkel discs

________ are touch receptors

Ruffini endings

receptors involved in touch/stretching

number

all humans have the same ____ of melanocytes

melanin

UV light stimulates ________ production

carotene

yellow to orange pigment found in carrots, it can accumulates in the stratum corneum and is most obvious in the palms and soles when carotene rich foods are eaten in high quantity

hemoglobin

the pigment that colors blood

dermis

Tattoos are permanent because they are injected into the _______

Palms, soles, lips

hair is present in most surface of the body except…

Insulation, protection, sensory

function of hair

shaft

hair projects above surface of skin

root

hair extends into the dermis

medulla

deepest layer of hair

cortex

middle layer of hair (contains hair pigment)

cuticle

outer layer of hair

hair matrix

area near the base of the hair where growth occurs

arrector pili

a smooth muscle that causes goosebumps

anagen

growth phase of hair - cells of matrix dividing. existing cells are pushed up and hair grows longer (2-6 years)

catagen

transtion stage of hair growth - cells of matrix stop dividing, and hair follicle atrophies (stops working). (2-3 weeks)

telogen

resting stage - papillae separates from follicle

shape of hair follicle

whether you have straight or curly hair depends on what

round

what shape of hair follicle is straight hair

oval

what shape of hair follicle is curly hair

100

normal hair loss is ___ hairs per day

alopecia

an autoimmune disorder that results in partial or complete lack of hair

sebacious gland

secretes oily sebum. usually connected to hair follicles. found all over the body except palms and soles. sebum keeps skin soft, coats hair, inhibit growth of some bacteria

eccrine glands

sweat gland found all over the body (even palms and soles). functions for thermoregulation and during stress.

apocrine

sweat gland found in armpit and groin. secrete a milky sweat and pheromones. They cause body odor. They do not function until puberty. Active during emotional stress and sexual activity.

ceruminous glands

modified sweat gland in the external ear. The secretion combines with sebum to make ear wax or cerumen. forms a sticky barrier to impede foreign particles and insects

ear wax

cerumen

nails

plats of hard packed, dead, keratinized cells

nail body

major visible portion of nail

nail root

nail part not visible

nail matrix

thickened proximal portion of the nail bed; responsible for nail growth

burns

tissue damage inflicted by intense heat, electricity, radiation, or certain chemical that denature cell proteins and cause cell death in affect areas.