Body Membranes and the Skin Chapter 4
Body Membranes • The body contains many membranes which serve a variety of functions including: • Covering body surfaces • Forming protective layer around organs • Membranes can be classified as either epithelial or connective tissue. • Most membranes are epithelial.
Connective Tissue Membrane • __membrane is the only type of connective membrane • Location: • Function:
Epithelial Membranes • Epithelial tissue is classified by the • Number of Layers: • Shapes:
Classification of Epithelial Tissue Simple squamous – Simple cuboidal – Simple columnar –
Classification of Epithelial Tissue (continued) • Stratified squamous – • Transitional –
Epithelial Body Membranes • There are three types of epithelial membranes: • Cutaneous membrane –
Mucous membranes – • Include • Cell type depends on location:
Serous membranes – • Serous fluid allows • Specific names of serous membranes: • Peritoneum – • Pleura – • Pericardium –
Integumentary System • Also known as the • Functions:
Structure of the Skin • The skin is composed of two main layers: • Deep to the dermis is a
The subcutaneous layer is not considered part of the skin, but it does a variety of necessary functions:
Epidermis • “Avascular” – • Most cells of the epidermis are “keratinocytes” –
Layers of the Epidermis(from deepest to most superficial) • Stratum Basale – • Contains “melanocytes” - • Melanin ranges from • Amount of melanin produced • Freckles and moles are areas of concentrated melanin
Layers of the Epidermis (cont.) • Stratum spinosum – • Stratum granulosum -
Layers of the Epidermis (cont.) • Stratum lucidum – 3 to 5 layers of dead, clear cells • Stratum corneum – • We have a totally new epidermis every 25-45 days!
Dermis • Divided into two major regions:
Papillary Layer • These bring • Also contain • On the hands and feet, the papillae are arranged in definite patterns to increase gripping ability = fingerprints!
Reticular Layer • Functions: • Contains
Quick Review • Identify the three types and locations of epithelial membranes. • What is the only type of connective membrane and where is it found? • What are the two layers of the skin? • What is the fat layer called beneath the skin? • How many layers are there in the epidermis?
Appendages of the Skin • Structures that support the functions of the skin • Include:
Sebaceous (Oil) Glands • Found everywhere in skin except • Usually • Produce oil which:
Sweat Glands • There are two types of sweat glands: • Secrete __composed of water, salt, and waste • Connected to the skin surface by a • Found in • Larger glands connected to hair follicles
H P E D S D D E S L A
Hair and Hair Follicles • Growths that serve minor protective functions (eyelashes, nose hairs, etc) • Structures: • Follicle – • Root - • Hair Shaft - • Hair papillae – • ArrectorPili – • When cold, these muscle contract and the hair is pulled upright = goosebumps
H E S G A F H P Or R
Graying • Hair pigment is made by melanocytes in the root. • Can stress turn hair gray? • Stress cannot turn hair gray, but can trigger a condition in which the hair sheds at 3x the normal rate. It’s likely that the hair which regrows will be gray for middle-aged individuals
Balding • Ordinarily, the hair should grow back but in men who are balding the follicle ceases to grow any hair. • The cause of baldness is not well understood, but is thought to be related to the genes and male sex hormones of the individual.
Nails Free Edge • Scalelike modification of the skin that corresponds to the hoof or claw of other animals • Each nail has a • The borders of the nail are overlapped by skin
Imbalances of the Skin • Ulcers (a.k.a. bedsores) – • Common in bedridden patients who are not rotated frequently • White and Blackheads – • Acne –
Imbalances of the Skin (Continued) • Psoriasis – • Treatment: slow production of skin cells through a variety of methods including steroids, vitamins, UV light, etc.
Imbalances of the Skin (Continued) • Infections: • Athlete’s Foot – • Cold Sores – • Note: • Both forms can remain dormant for periods of time
Infections (continued): • Shingles – • After having Chicken pox, • Staph – • Most staph infections are easily treated by antibiotics