Integumentary System

epidermis 

stratified squamous, avascular 

dermis

deeper CT, contains blood vessels, glands, and sensory nerves

hypodermis

areolar and adipose, pads body, drug injections here

examples of thick skin

palms, soles, fingers, toes

thick skin

has sweat glands, and think stratum corneum

does NOT have hair follicles or sebaceous oil glands

thin skin 

has hair follicles, sebaceous glands and sweat glands 

thinner epidermis 

protection

keratin provides toughness

acid mantle and antimicrobial peptides defend bacteria

barrier

protects against water loss, UV radiation, and chemicals

vitamin D syntesis

skin carries out the first step in producing this

important for calcium balance

thermoregulation 

blood vessels dilation/constriction regulates heat

nonverbal communication

facial expressions

the epidermis is _______

avascular

keratinocytes

(cell in epidermis) 

produces keratin

stem cells 

(cell in epidermis) 

found in the stratum basale, glues rise to the keratinocytes 

melanocytes

(cell in epidermis) 

produces melanin (protects DNA from UV)

tactile (merkel)

(cell in epidermis) 

sensory receptors for touch

dendritic (langerhans)

(cell in epidermis) 

immune cells that protect against toxins microbes

corneum

(layers of epidermis)

up to 30 layers of dead keratinized cells

protection, and water resistance

lucidum

(layers of epidermis)

only in thick skin

thin layer of dead cells filled of protein called eleidin

granulosum 

(layers of epidermis)

cells start dying and fill with keratin 

forms a water barrier to prevent dehydration 

spinosum

(layers of epidermis)

cells are alive and connected by spiny attachments (desosomes) contain dendritic cells (Immudefense)

basale 

new skin cells (keratinocytes) are made by stem cells, which also contain melanocytes (make pigment) and tactile cells (sense touch) 

keratinocyte

produced in the stratum basal, migrate upward, flatten, and die

38-40 days from birth to exfoliation

faster with injury or stress, slower with aging

callus/corns

thick accumulations of keratinocytes

dermis composition

collagen, elastic and reticular fibers

papillary 

(layer of dermis) 

areolar CT

near dermal papillae 

allows immune cell movement

rich in small blood vessels 

reticular layer

(layer of dermis)

dense regular CT

deeper and thicker

stretch marks

collagen fiber tears

hypodermis tissue type

areolar and adipose

hypodermis functions

energy storage, insulation, and shock absorption

the hypodermis is ______

thicker in woman

thinner in infants and elderly

skin color 

determined by melanin (eumelanin phemelain), coratene, and nemoglobin visibility

erthema

redness

high blood flow

pallor

pale

low blood flow

cyanosis

blueness

oxygen deficiency

jaundice 

yellowness 

bilirubin build up 

albinism

no melanin

hematoma

bruising

clotted blood under skin

nails

derived from the stratum corneum

made of hard keratin 

function of nails 

protect finger tips 

aid precision and grip 

parts of a nail

free edge

nail body

nail root

nail matrix (growth zone)

cuticle (eponchium)

oxygen deficiency

clubbed nails may indicate __________

eccrine (merocrine)

produce a watery sweat that is secreted directly onto the skin and is the main type of sweat for cooling the body; they become active at birth and are found throughout the body

apocrine 

secrete a thicker, viscous sweat that connects to hair follicles and becomes odorous when broken down by bacteria, primarily functioning at puberty

sebaceous glad

secrete sebum (oil) into hair follicles lubricates skin/hair

ceremonious glands

in ear canal produce cerumen (ear wax)

mammary glands

modified apocrine glands for milk production

lanugo 

(hair type) 

fine

unpigmented 

fetal 

vellus

(hair type) 

fine

pale

body hair in children and women

terminal

(hair type) 

coarse

pigmented

scalp, brows, lashes, post-puberty regions

structure of hair

bulb (living cells), root, and shaft

follicle with epithelial and connective root sheaths

arrector pili muscle causes goosebumps

alopecia 

baldness 

pattern baldness

a common, hereditary type of hair loss that follows a predictable pattern, most often a receding hairline and thinning on the crown of the head

hirsutism

excess hair from hormone imbalance

1st degree

epidermis only

red

mild pain

2nd degree 

epidermis and part of dermis 

blistering 

3rd degree

epidermis, dermis, and deeper tissues

requires grafts

fluid/nutrient replacement

basal cell carcinoma

most common

least danger

stratum basale

squamous cell carcinoma

from stratum spinosum

can metastasize to the lymph notes

malignant melanoma 

aggressive and fatal 

linked to UV exposure and genetics