Download Chapter 6 Summary 2401 -2015

SUBJECT: ANATOMY & PHYSIOLOGY
BIOL 2404-I02
Chapter 6
The integumentary system (skin)
1.
Skin functions include protecting the deeper tissue from chemicals, bacteria, bonds,
and drying; regulating body temperature through radiation and sweating; and since
the sizing defensive proteins and vitamin D. The cutaneous sensory receptors are
located in the skin.
2.
The epidermis, the more superficial part of the skin, is form of stratified squaw must
care tonight is a epithelium and is avascular (no blood vessels). Moving from its
superficial to deep regions, its layers are the :
A. stratum corneum - thick outer layer, all dead keratinized cells.
B. stratum lucidum - found in thick skin only, 2-3 layers of dead cells.
C. stratum granulosum - 4-5 layers of dying cells; keratinization begins here.
D. stratum spinosum - several layers; dendritic cells found in this layer.
E. stratum basale - the germinating layer, 1 layer of rapidly dividing cells.
Keratinocytes, melanocytes, and tactile (Merkel) cells found here.
F. Cells at its surface are dead and continually flake off. They are replaced by
division of cells in the basal cell layer. As the cells move away from the basal
layer, they accumulate keratin and die. Melanin, a pigment produced by
melanocytes, protects the nuclei of epithelial cells from damaging rays (UV) of
the sun.
G. Skin color comes from 3 sources: blood in capillaries (pink); melanin (brown to
black) and carotene (yellow).
3.
The dermis is composed of dense connective tissue. It is the site of blood vessels,
nerves, and epidermal appendages. It has two regions, the papillary and reticular
layers.
A. The papillary layer has epidermal ridges which press on the epidermis to form
fingerprints. These ridges interlock with dermal papillae to tightly join the
epidermis to the dermis. Capillaries are present in the dermal layer.
B. The reticular layer is the thicker of the 2 layers. It contains blood vessels,
nerves, several tactile organs, sweat and sebaceous glands, and hair follicles.
4.
Skin appendages are formed from the epidermis but reside in the dermis.
A. Sebaceous glands produce an oily substance (sebum), usually ducted into a
hair follicle. Sebum keeps the skin and hair soft, and contains bacteria killing
chemicals.
PAGE 1 OF 3
DR. DAVID L. COX
SUBJECT: ANATOMY & PHYSIOLOGY
BIOL 2404-I02
B. sweat (sudoriferous) glands, under the control of the nervous system, produce
sweat, which is directed to the epithelial surface. These glands are part of the
body’s heat – regulating apparatus. There are two types: merocrine (the most
numerous) and apocrine (their products include fatty acids and protein which the
skin bacteria metabolized to cause BO).
C. Ceruminous glands are modified sweat glands and produce cerumen (ear wax).
D. Mammary are also modified sweat glands and produce milk.
E. A hair is primarily dead keratinized cells and is produced by the matrix in the hair
bulb. The root is enclosed in the sheath, the hair follicle.
F.
5.
6.
Nails are more like the release of the epidermis. Like hair, nails are primarily
dead keratinized cells. Skip the section on hair and nail structure.
Skip the section on wound repair.
Burns - know which layers 1st, 2nd, and 3rd degree burns affect.
Review figure 4.3 – anatomy of the skin.
Review figure 4.4 - layers of the epidermis.
PAGE 2 OF 3
DR. DAVID L. COX
SUBJECT: ANATOMY & PHYSIOLOGY
BIOL 2404-I02
Classification of body membranes
7.
Epithelial: simple organs, epithelium, and connective tissue components.
A.
Cutaneous (the scan): epidermis (stratified Squanto 7 PM) underlined by the
dermis (dense connective tissue); protects body surface.
B. Mucous: apathy or sheet underlain by lamina propria (Arielle or connective
tissue) called on lines body cavities open to the exterior.
C. Serous: simple squamous epithelium resting on a scant connective tissue layer;
lines the ventral body cavity.
2.
Connective tissue: synovial; lines joint cavities.
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DR. DAVID L. COX