Integumentary systemIntegumentary systemThe skin and accessory organs (Hair, membranes, glands, etc)

MembranesMembranesSerous membranesSerous membranes: Line body cavities that lack openings to the outside.

is a smooth membrane consisting of a thin layer of epidermal cells

They line and enclose several body cavities, where they secrete a lubricating fluid which reduces friction from muscle movement.

MembranesMembranesSerous membranesSerous membranes: Basically they cover

areas such as thethoracic cavity the heart and lungs area, and ventral cavity.

MembranesMembranesSerous membranesSerous membranes:

MembranesMembranesMucous membranesMucous membranes:are involved in absorption and secretion.

They line various body cavities that are exposed to the external environment and internal organs.

Examples are the nasal and oral cavities, tubes of the respiratory, digestive and reproductive tracts.

Mucous membranesMucous membranes:Usually found near or on glands that will help secrete a mucous.

It is at several places continuous with skin.

Why would you find mucous membranes continuous or near or connected to your skin?

MembranesMembranes

MembranesMembranes

Synovial membranes: Synovial membranes: is the soft tissue that lines the non-cartilaginous surfaces within joints (synovial joints).

They secrete a fluid to lubricate the joints.

MembranesMembranes

MembranesMembranesSynovial membranes: Synovial membranes:

Cutaneous membranes: Cutaneous membranes: The skin They consist of stratified squamous epithelium and the underlying connective tissues. Cutaneous membranes are thick, relatively waterproof, and dry.

The skin helps in regulating body temperature and maintaining homeostasis.

MembranesMembranes

MembranesMembranesCutaneous membranes:Cutaneous membranes:

THE THREE LAYERS OF THE THREE LAYERS OF SKINSKIN

1. EPIDERMIS2. DERMIS3. SUBCUTANEOUS

LAYER

EPIDERMISEPIDERMISThe outer layer

Composed of stratified squamousepithelium

Contains five separate layers: Stratum Corneum- Stratum Corneum- outer most layer- mostly dead cellsStratum Basale- Stratum Basale- The area where cells divide rapidlyStratum SpinosumStratum SpinosumStratum Granulosum-Stratum Granulosum- only in areas where the skin is thickStratum lucidumStratum lucidum- only on the palms and soles.

EPIDERMISEPIDERMIS

5 Layers of Epidermis:

Here is what happens to make these layers: ◦1. The basale layers divide rapidly pushing the cells and tissues up toward the top.

◦2. The closer they get to the top the less nutrients they have from the connective tissue so they eventually die (This becomes your Corneum layer)

EPIDERMISEPIDERMIS

The process of these cells hardening and dying is called KERATINIZATION

◦This is when they can secrete the protein Keratin to make the skin tough and water proof.

EPIDERMISEPIDERMIS

Your epidermis also contains MELANIN:MELANIN: is a dark pigment that provides your skin color. ◦Melanocytes are the cells that produce the melanin. They are found in the deep layers of the epidermis.

◦WHY Would you want them in the deep layers instead of the corneum?

EPIDERMISEPIDERMIS

HOW or why do you think people have different colors of skin then? DISCUSS with your table and come up with an answer!

EPIDERMISEPIDERMIS

EPIDERMISEPIDERMIS

Most people have the same number of melanocytes but the differences are due to the amount of melanin they produce.

It is genetic!!

If genes instruct the melanocytes to produce a lot of melanin then your skin is darker.

EpidermisEpidermis

How do you think sunlight plays a role in melanin and skin color? (Obviously sun UVA rays can make you darker- but why do you think so?) DISCUSS as a table and come up with an answer to report out.

EPIDERMSEPIDERMS

ANSWER: The sun stimulates (Speeds up) production of the melanin pigment.

Some people depending on how dark their skin is can turn “red” or “blush” and it can be seen. What do you think is happening there to temporarily change the skin color?

EPIDERMISEPIDERMIS

ANSWER: When the blood vessels in the lower layers of the skin are well oxygenated the blood pigments appear bright red (hot). When the oxygen content is low, the skin can appear blueish (cold).

Remember I said skin has something to do with regulating body temperature- here is one way it doe that!

DERMISDERMISKnown as the Inner layerVery thickContains: Connective tissues, epithelial

tissues, smooth muscle tissue, nervous tissue and blood vessels.

This is where your fingerprints come from. Supplies nutrients to the epidermis and

regulates body temperature.

Contains sensory receptors (touch receptors, temperature receptors- sweat glands, and so forth)

Also contains the HAIR FOLLICLESHAIR FOLLICLES, SWEAT SWEAT GLANDSGLANDS, and SEBACACEOUS GLANDSSEBACACEOUS GLANDS

DERMISDERMIS

HAIR FOLLICULE:HAIR FOLLICULE: Hair is present everywhere except: palms, soles, nipples, and some external reproductive parts.

Hair develops from a group of epidermal cells at the base of a hair follicule that divide and grow until they are pushed up and out and are dead.

DERMISDERMIS

SO HAIR IS DEAD- What type of dead cells do you think they are? DISCUSS and come up with an answer.

DERMISDERMIS

ANSWER: Once the cells get pushed up they become the keratinized dead epidermal cells.

Think back to what we talked about with Melanin and skin color. HOW do you think genetics and melanin determine hair color? DISCUSS as a group and come up with an answer.

DERMISDERMIS

Answer: Genes determine the type and amount of pigment the melanocyte cells will produce. So your hair follicles have melanocyte cells at the base of them.

If these cells at the base of the follicle produce a lot of melanin the hair will be darker.

When you get older how does your hair start to turn gray and then white?

DERMISDERMIS

ANSWER: The melanocyte cells eventually over time die and stop producing melanin.

A person with RED hair is the exception- they have a pigment called: Trichosiderin.

Arrector Pili muscle: a smooth muscle attached to the hair follicle.

Why do you think your skin would need a muscle attached to the hair? What does it do?

Answer: Causes your hair to “stand up” when you have the goosbumps- either emotional response or cold.

DERMISDERMIS

Sebaceous Glands: Sebaceous Glands: associated with hair follicles. Secrete oil called sebum through small ducts into the hair.

Helps keep hair and skin soft and waterproof.

DERMISDERMIS

SWEAT GLANDS:SWEAT GLANDS: There are different types of sweat glands. ◦Eccrine glands: Eccrine glands: respond to a rise in temperature and are located on the forehead, neck and back where they produce droplets of sweat to cool the body down.

◦Apocrine glands: Apocrine glands: become active at puberty or when a person is emotionally upset. (arm pit region or groin).

Sweat Gland:

DERMISDERMIS

Sweat glands: sweat is more than just water- contains salts and other wastes.

Sweat glands help regulate body temperature.

SUBCUTANEOUS LAYERSUBCUTANEOUS LAYERBeneath the dermisConsists of Loose Connective tissue and

Adipose. Contains most of the blood vessels for

supplying the epidermis nutrientsAlso insulates- conserving body heat and

keeps too much heat from coming into the body.

THE THREE LAYERS:

THE SKIN: THE SKIN:

LABEL THE DIAGRAM: