October 30, 2014 Journal: What makes up the Integumentary system?

Integumentary System

Made up of: Skin Hair Nails Associated Glands

Functions: Protection Keeps the body from drying out Stores fatty tissues to be used as an energy source Produces vitamin D with the help of sunshine Sensory input for your brain Regulates body temperature

Skin Made up of 3 tissue layers: – Epidermis – Dermis – Subcutaneous fascia a.k.a. hypodermis

Epidermis Outermost layer of skin Made up of 4-5 layers or stratified squamous epithelial tissue Contains 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 shed Typically flat, scaly, and keratinized (hardened) epithelial cells Protect 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 = tan Freckles occur when melanin is found together in clumps Yellowish skin tone is due to carotene Pinkish skin tone is due to hemoglobin Yellow 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 epidermis Thick 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 fingerprints Reticular 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 brain Connect 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 hypodermis Innermost layer of skin Composed of fatty tissues and elastic and fibrous connective tissue Connects 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