anatomy and physiology of the skin

three main layers of the skin are

epidermis

dermis

hypodermis or subcutis or subcutaneous layer

epidermis consists of

layers made of stratified epithelium, outer layers are dead and cornified.

The epidermal layers are divided into two main layers called:

horny zone and germinal zone

the horny layer

is the outer portion of the epidermis

horny layer is divided into three layers of different cells

stratum corneum

stratum lucidum

stratum granulosum

the outermost layer of the epidermis is the

stratum corneum

stratum lucidum is only present in the ___ and ___ where the epidermis is the thickest

palms of hands and the soles of the feet

the bottom of the horny layer lies the

stratum lucidum

stratum granulosum is also known as the

granular layer

persistent friction and pressure cause areas to thicken for protection and form

calluses/keratoma

germinal also known as

basal zone or the living

the basal zone is made up of 2 layers

stratum spinosum and stratum germinativum

stratum spinosum is also known as the

prickle cell layer

the stratum germinative is the ____ of the epidermis and is in contact with the dermis

lowest layer

stratum germinativum is the layer in which ___ happens called mitosis

cell division

desquamation takes qpproxiamtley how many days

28

the stratum mucosum combined with the stratum germinative is known as the

malpighian layer

the dermis is often called the

living layer or “true skin”, cornium, cutis vera

the dermis layer is divided into 2 layers called

papillary and the reticular layer

papillary layer lies directly below the dermis and is made of

dense elastic collagenous and reticular fibers that are cone shaped

cone shaped, finger like projections called

papillae

the thickest layer of the dermis is the

reticular layer

lymph glands produce lymph which is made up of :

white blood corpuscles and plasma

lymph contains

waste products, salts, and nitrogenous wastes

sudoriferous glands are also called the ______ and are under control of the sympathetic nervous system

sweat glands

the two kinds of sweat glands are called

apocrine and eccrine

apocrine glands are found ____ and mix with bacteria to create an ____ (osmidrosis)

in the genital and axillary, oder

sebaceous glands are found

all over the skin

the sebaceous glands produce an oily substance called

sebum

nerve endings carry what to the brain

impulses

hair is also part of the

pilosebaceous unit

subcutaneous layer is located at the base of the dermis and is also called

subcutis or adipose tissue

epidermal cells are responsible for producing the

hair follicle and the hair matrix

the dermal papillae is at the base of the hair __

bulb

A tiny muscle that is responsible for lifting the hair and trapping a layer of air on the skins surface

arrector pili muscle

the sebaceous gland also prevents the epidermis from

drying, cracking and prevents bacteria and germs from entering the skin

the 3 layers of the hair are

cuticle

cortex

medulla

the outermost of the hair layers is called the _____ and composed of cells that overlap like scales

cuticle

the middle layer of the hair is called _____ and is made up of elongated cells of fibrous tissue and the pigment that gives hair its color

cortex

the innermost layer of the hair is _____ and is made up of round cells

medulla

the medulla is also called the

pith or marrow

the 3 main types of hair

lanugo

vellus

terminal

lanugo hair is

soft downy hair also called “fetal hair” and sheds few weeks after birth

vellus hair is

also called “peach fuzz” and is fine, short hair with almost no pigment

terminal hair is

longer, coarser, pigmented hair

the three main stages of hair growth are

anegan

catagen

telogen

the skin has 6 functions including

secretion, excretion, heat regulation, absorption and protection and sensation (vitamin D synthesis)

the skin has a built in protective aid known as the

acid mantle

the acid mantle has ph of

5 to 5.6 (7 being neutral)

unwanted organisms are recognized by _____ cells in the epidermis that warn against invading microorganisms

langerhan

intact skin protects against fluid from entering the body but also prevents water, blood, and lymph from leaving the body known as

TEWL (trans epidermal water loss)

adipose tissue protects our body from

falls, and minor truama and keeping our body warm

lymphocytes act as a

second line of defense against bacterial invasion and carry bacteria to the lymph nodes for filtration

a healthy temperature for the human body is

98 degrees

evaporation or perspiration on the skin’s surface produces cooling also known as

thermoregulation

sensation is

the skin’s ability to register heat, cold, pain and pressure