Chapter 5: Integumentary System
Terms
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- 2 distinct regions of the skin are?
- Epidermis and Dermis
- How are teh top epithelial tissues fed if only the dermis is vascularized?
- Nutrients diffuse through the tissue for the epidermis to recieve nourishment.
- The subcutaneous tissue just deep to the dermis is know as?
- Hypodermis or superficial fascia
- Half of th bodys fat is stored here. This region anchors skin to the underlying organs. It acts a shock absorber and insulator
- Hypodermis
- 4 Type of cells found in the epidermis are?
-
1. Keratinocytes
2. Melanocytes
3. Langerhans cells
4. Merkel cell - Most numerous of th skin cells. Produce keratin-waterproofs skin. Cells arise fron teh deepest part of the epidermis.
- Keratinocytes
- Located ant teh base of the epidermis. Produce the pigment melanin. same # of cells in everyone/diff activity causes diff color races.
- Melanocytes
- What is the role of melanin in the skin?
- Melanin protects the cell nucleus from the destructive effects of UV radiation.
-
Arise from bone marrow and migrates to the epidermis and other areas of the body containing stratified squamous epithelial tissue.
Macrophages-assist in immune response - Langerhans Cells
- found in small #'s at the dermal/epidermal junction. Sensory receptor
- Merkel cells
- Disc-like ending of a sensory nerve fiber
- Merkel Discs
-
How many layers of:
Thin Skin?
Thick Skin? -
4 layers: thin
5 layers: thick -
Name the layers of the epidermis:
C
L
G
S
B -
Stratum corneum
Stratum Lucidum (+ -)
Stratum Granulosum
Stratum Spinosum
Stratum Basale - Stratum layer that is 20-30 layers thick. 3/4 of epidermal thickness. Dead, completely filed with keratin.
- Stratum Corneum
- Clear Layer, Present only in thick skin
- Stratum Lucidum
- Stratum layer of 3-5 layers of cels where keratinization begins. Langerhans cells found here.
- Stratum Granulosum
- Stratum layer with spiney projections. Some mitosis occurs. Langerhans nd keratinocytes found here
- Stratum spinosum
- Stratum layer with wingle layer of cuboidal to columnar shaped cells. Seperated from the dermis by the BM. Many mitotic cells here 25% are melanocytes.
- Stratum basale
- What cell types are found in the dermis?
- fibroblasts, macrophages, some mast cells and white blood cells
- What are the 2 layers of the dermis?
-
Papillary
Reticular - Superficial layer of the dermis. Very vascular. Arranged in patterns that make whirled loops on the ventral sides of the hands and feet.
- Papillary Layer
- What 3 pigments contribute to the skins color?
-
1. melanin
2. carotene
3. hemoglobin - What are 3 effects of increases exposure to UV radiation?
-
1. Clumping of elastin fibers leasing to "leathery" skin
2. temporarily depresses the immune system
3. can alter the DNA od skin cells leading to cancer. - What are the appendages of the skin?
-
1. hairs
2. hair folicles
3. nails
4. sweat glands
5. sebaceous glands
all 5 are derived from the epidermis - What is the function and structure of hair?
-
function: protect head from trauma, heat loss and sunlight. shield dust-eyelashes and nose hairs
structure: 3 concentric layers of keratinized cells
1. core-mdulla
2. cortex-bulky layer
3. cuticle-outer strong layer - Sensory nerve ending that wraps around the hair follicle bulb
- root hair plexus
- nipple like knot of capillary tissue that protrudes into the hair bulb and supplies it with nutrients.
- Papila
- structures associated with hair folicles
- 1. nerve endings 2. sebaceous glands 3. smooth muscle sructure (involuntary)-arrector pili
- goose bumps are a result of this smooth muscle contracting
- arrector pilli
- Lips, nipples, external genitalia and the thick areas of the hands and feet lack this
- hair
-
2 types of hair:
thin hair is called ?
thicker coarser hair is called? -
vellus
terminal - 2 factors that can influence hair growht and density:
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1. nutrition
2. hormones - 2 types of sweat glands and where are they found?
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1. eccrine- palms,soles and forehead 99% water
2. apocrine- found in the auxillary and anogenital regions. secrete water along with fatty substance and proteins. odorless until bacterial decomposition occurs -
Secretes ear wax
Secretes milk -
Ceruminous Glands
Mammary Glands - Secretes sebum. softens and lubricates hair and skin. Antibacterial properties.
- Sebaceous Glands
- Bacteri responsible for acne
- staphylococcus
- Least malignant skin cancer. cells in the stratum _ are altered and can't form _.
-
Basal Cell Carcinoma
Stratum Basale
Keratin - Arises from keratinocytes in the stratum _. causes red papule found most often on the scalp, ears,dorsum of the hands and lower lip.
- Squamous Cell Carcinoma
- Deadly cancer of the _. Begins wherever there is pigment present.
- Malignant Melanoma
- Describe the ABCD rule for evaluating skin lesions
-
A. Assymmetry - 2 sides dont match
B. Border - irregular, not smooth
C. Color - pigmented spot
d. Diameter - larger than 6mm