Biology report 2nd semester part 2

The Integumentary System

Definition:

• is comprised of the skin and its accessory components of hairs, nails and associated glands.

• Performs several vital functions besides protecting you from an invasion of disease-producing pathogens

• helps keep the body from drying out, acts as storage for fatty tissue necessary for energy, and with the aid of some sunshine, your skin produces vitamin D.

Skin:

• quite a large organ, easily weighing twice as your brain, approaching 20 pounds in an average adult

• 3 main layers:

1. epidermis:

   - layer of skin that we normally skin.

   - made up of 5 or 6 even smaller layers of stratified squamous epithelium

   - the epidermis is interesting for several reasons:

   - 1^st, it has no blood vessels or nerve cells.

   - 2^nd, the cells on the surface are constantly shedding being replaced with new cells that arise from the deeper region called, “ Stratum basale.”

   - the outermost surface of skin is actually a layer of dead cells called stratum cornerum

   - specialized cells called melanocytes are located deep in the epidermis and are responisble for skin color. They produce melanin, which is the actual substance that affects skin color.

2. Dermis;

   - another name: Corium

   - made up of the following components in the layer:

• capillaries

• collagenous and elastic fibers

• involuntary fibers

• nerve endings

• lymph vessels

• hair follicles

• sudoriderous glands

• sebaceous glands

• 2 main types of sudiferous or sweat glands:

  1. apocrine

  - secrete at the hair follicles in the groin and region as well as the armpits.

  2. eccrine

  - found in greater numbers on your palms, feet, forehead, and upper lip

3. Subcutaneous Fasci ( Hypodermis)

   - the innermost layer of the skin which is composed of elastic and fibrous connective tissue and fatty tissue.

Nails

- specialized epithelial cells originating from the nail root form your nails. As these cells grow out and over the nail bed, they become keratinized, foring a substance similar to the horns of a bull

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Skin Burns

When assessing the damage caused by the burns, there are two factors:

1. The depth of the burn

2. size of the area damged

Types of Skin Burn ( in order)

1. 1^st degree burn - damages the outer layer of the skin only

2. 2^nd degree burn - burns the entire depth of the epidemis and a portion of the dermis

3. 3^rd degree burn - affects all of the 3 layers of the skin

4. 4^th degree burn - burns that penetrate to the bone