October 30, 2014

Journal: What makes up the Integumentary system?

Integumentary System

Made up of:

SkinHairNailsAssociated Glands

Functions:

ProtectionKeeps the body from drying outStores fatty tissues to be used as an

energy sourceProduces vitamin D with the help of

sunshineSensory input for your brainRegulates body temperature

SkinMade up of 3

tissue layers:– Epidermis– Dermis– Subcutaneous

fascia a.k.a. hypodermis

Epidermis

Outermost layer of skinMade up of 4-5 layers or stratified

squamous epithelial tissueContains no blood vessels or nerve cells

Epidermis Layer Shedding

Surface cells are constantly shedding Cells originate in the basal layer (stratum

basale) and are pushed upward towards the surface

As they are pushed upwards the cells die and become filled with a protein called keratin

This process takes between 2 and 4 weeks

Layers of the Epidermis

Stratum corneum

Dead cells on the outermost surface of the skin

Often shedTypically flat, scaly, and keratinized

(hardened) epithelial cellsProtect the layers underneath from

drying out

Stratum lucidum

Layer of dead, keratinized epithelial cells only found in parts of the body with thick skin– Ex: Palms and heels

Functions in protection from UV rays

Stratum granulosum

Skin layer in the middle of the epidermis where living cells are filled with keratin and begin to die

Stratum spinosum

Living epithelial cells that do not receive nutrients from the dermis, but divide at a slow rate

Contain Langerhans cells that can produce an immune response when pathogens are present

Stratum basale

Living epithelial cells that receive nutrients from the dermis and undergo rapid mitosis to replace cells lost in the stratum corneum

Contains melanocytes which are responsible for producing pigment

Contains Merkel cells which are touch receptors

Melanocytes

Produce melanin, the substance that is responsible for your skin color

Variations in skin color are due to how much melanin is produced and how it is distributed around your body

Skin Color

More sun = more melanin produced = tanFreckles occur when melanin is found

together in clumps Yellowish skin tone is due to carotene Pinkish skin tone is due to hemoglobinYellow jaundice occurs when liver disease

occurs and the body can’t excrete waste

How getting a tan works

When you get a tan, what is actually happening is that the melanocytes are producing melanin pigment in reaction to ultraviolet light in sunlight. The pigment has the effect of absorbing the UV radiation in sunlight, so it protects the cells from UV damage.

In other races, melanin production is continuous, so the skin is always pigmented to some degree. In these races the incidence of skin cancer is much lower because cells are constantly protected from UV radiation by melanin.

November 3, 2014

Objective: To describe the layers of the skin and the accessory organs found within them

Journal:– List the layers of the epidermis from the

outside to the inside of the body.

Dermis Layer right below the epidermisThick layer of irregular connective

tissue

Two Layers within the Dermis:

Papillary Layer– Top layers of the dermis– Contains thin elastic and collagen fibers– Contains ridges that are responsible for

fingerprintsReticular Layer

– Below the papillary layer– Contains tightly packed elastic and

collagen fibers

Found within the Dermis:

Blood vessels

Bring nutrients to the skin and carry waste away from it

Collagenous and elastic fibers

Helps your skin shift when you move your body otherwise it would tear

Allows skin to return to its normal shape when your body is at rest

Stretches out over time so skin loses it’s firmness and flexibility

Nervous tissue

Carry nerve impulses to the brainConnect to Merkel cells in the epidermis

Lymph Vessels

Transport fluids from the tissues to the circulatory system

Hair follicles

Sweat Glands

Apocrine sweat glands– Located near the hair follicles, groin, and armpits– Become active around puberty and act as a

sexual attractant Eccrine sweat glands

– Located all over your skin– Regulate body temperature

** Body odor isn’t actually from sweat, but from bacteria breaking down substances in it

Sebaceous Glands

Oil glands that keep the skin from drying out

Destroys pathogens on the skin as well

Subcutaneous fascia

Also known as hypodermisInnermost layer of skin Composed of fatty tissues and elastic

and fibrous connective tissueConnects to the muscles of your body

Lipocytes

Fat cells produce the fat needed to protect the body and to act as insulation for regulating temperature