Chapter 4 Anatomy

integumentary system

4-5 weeks

ectoderm

simple squamous —> stratified squamous

6-7 weeks

deeper skin into mesoderm

8-9 weeks

mesenchyme (stem cells form)

fibroblasts begin to form

dents form, lanugo (hair)

10 weeks

barrier forms between outer and inner layers

11 weeks

nails form because of blood vessels (angiogenisis (process))

20 weeks

glandular structure

23 weeks

pigmentation comes from melanoblasts

melanoblasts —> melanocytes

integument

skin

inherent

refers to qualities a person or animal is born with

adaptive

refers to the ability of an organisms genes to respond to environmental changes

Mucous membrane

lubricated inner lining that secretes mucus

mesenchyme

embryonic connective tissue (made of stem cells)

Fibroblast

a cell that secretes proteins that form collagen and elastin fibers

lanugo

temporary, fine body hair found on babies

Angiogenic factors

Chemical secretions that help stimulate, or develop, the growth of new blood vessels

Angiogenisis

the formation of blood vessels (process)

pigmentation

skin coloration

melanoblast

a cell that will develop into a membrane and produce pigment

melanocyte

a cell that produces pigment

Epidermis

outermost layer of skin

dermis

the middle layer of skin, formed from mesenchyme cells

“true skin”

hypodermis

subcutaneous layer

innermost layer of skin

Stratum Basale or Stratum Germinativum

the innermost layer of the epidermis

Stratum

layer

Dermal Papillae

rigid layers of the dermis that are bound tightly to the stratum germinativum 

Malpighian layer

the layer of epidermis containing melanocytes 

Melanin

a black- or brown- colored chemical that gives color to skin 

Melanosomes

organelles in which melanin is produced 

Stratum Spinosum

the second innermost layer of the epidermis

Langerhans cells

cells that assist fighting skin infections and healing injured skin

Stratum Granulosum

the middle layer of the epidermis 

Keratin

a yellow sulfur-rich protein that gives skin its strength

Keratocytes

cells that contain keratin

Stratum Compactum

the second outermost layer of the epidermis 

Stratum Lucidum

a breakable layer of epidermis found in areas of thick skin

Stratum Corneum

the outermost layer of the epidermis

Desquamation

the process of shedding dead skin cells 

Hemidesmosome

a specialized junction between on epithelial cell and the basement membrane 

Areolar connective tissue

a connective tissue that binds blood vessels, membranes, muscles, nerves, and skin to other structures 

Fascia

fibrous tissue covering muscles, the skull, and some organs 

Adipose tissue

a type of body tissue containing stored fat to be used for an energy source

Capillaries

narrow thin-walled blood vessels

Fasciitis

inflammation of the fascia

Skin appendages

complex structures that assist skin function

Ceruminous glands

the large glands in the skin of the ear canal

Cerumen

a waxy secretion produced by the ceruminous glands 

Apocrine

refers to secretions consisting of pinched cytoplasm, including some plasma membrane

Sebaceous gland

a gland that secretes sebum into the hair follicle  

Holocrine gland

secretions composed of dead cells that swell with fat and then rupture

Sebum

an oily secretion produced by the sebaceous glands

Hair follicle or Hair bulb

an inward protrusion of the epidermis 

Sweat gland

a gland that produces sweat 

Apocrine sweat glands

sweat glands that secrete sweat into hair follicles

Pheromones

chemicals secreted by apocrine sweat glands; thought to play a role in courtship and social behavio

Eccrine sweat glands

sweat glands that secrete mostly water and salts