Term
| What is our largest organ? How much of our body weight does it account for? |
|
Definition
|
|
Term
| The skin is divided into which layers: |
|
Definition
Two:
1. Epidermis=epithelium
2. Dermis=connective tissue |
|
|
Term
|
Definition
lies deep to the dermis
Adipose (fat) |
|
|
Term
|
Definition
Cushions and insulates deeper organs
-Maintains temperature
Protects body from bumps, scrapes and cuts
Protects body from chemicals, heat, and cold
Acts as a mini-excretory system
Screens out UV rays from sun
Contains sensory receptors associated with nerve endings |
|
|
Term
| What are the most abundant cell type in epidermis? |
|
Definition
|
|
Term
What do keratinocytes arise from?
What do they produce? |
|
Definition
arise from deepest layer of epidermis
produce keratin a tough fibrous protein
and produce antibodies and enzymes |
|
|
Term
| At the skin's surface, keratinocytes: |
|
Definition
| are dead, they continually shed (a large portion of household dust is keratinocytes) |
|
|
Term
| List the layers of Epidermis |
|
Definition
1. strattum basale (stratum geminativum)
2. stratum spinosum
3. stratum lucidum
4. Stratum lucidum (only in thick skin)
5. Stratum corneum |
|
|
Term
What is the deepest layer of epidermis?
What is it attached to?
What do the cells do?
What does it contain? |
|
Definition
Stratum basale
Attached to underlying dermis
Cells actively divide
Stratum basale contains:
-Merkel cells and Melanocytes |
|
|
Term
What are merkel cells and melanocytes?
Where are they> |
|
Definition
In stratum basale
Merkel cells- associated w/sensory nerve endings
Melanocytes- secrete the pigment melanin |
|
|
Term
| Which layer of the epidermis has a spiny appearance? What is it caused by? What does it contain? |
|
Definition
Stratum spinosom- spiny b/c artifacts of histological preparation
Contains thick bundles of intermediate filaments (tonofilaments) And contains star-shaped langerhans cells |
|
|
Term
| Which layer consists of keratinocytes and tonofilaments? What do the tonofilaments contain? |
|
Definition
Stratum granulosum
Tonofilaments contain keratohyaline granules- help to form keratin |
|
|
Term
| Which layer of the epidermis is clear? Where does it occur? What is it composed of? |
|
Definition
Stratum lucidum
occurs only in thick skin
composed of a few rows of flat dead keratinocytes |
|
|
Term
| Which layer of the epidermis is the horny layer? What is it composed of? What is its function? |
|
Definition
Stratum corneum
Thick layer of dead keratinocyts and thickened plasma membranes
Protects skin against abrasion and penetration |
|
|
Term
What is the second major layer of skin? Where is it?
Describe it
Richly supplied with-?
What are the layers? |
|
Definition
Dermis,
under epidermis
strong, flexible connective tissue
Richly supplied with blood vessels and nerves
2 layers:
Papillary layer
Reticular layer |
|
|
Term
What are the Papillary layer and
Reticular layer |
|
Definition
Papillary layer- includes dermal papillae; loose connective tissue
Reticular layer- deeper layer 80& of thickness of dermis, dense irregular connective tissue. |
|
|
Term
The hypodermis is -- to the skin, and is also known as --
Contains -- tissues
Functions: |
|
Definition
Deep to skin, aka superficial fascia
Contains Areolar and Adipose Connective Tissue
Anchors skin to underlying structures
Helps insulate the body |
|
|
Term
What is Hair?
Chief parts of hair? |
|
Definition
Flexible strand of dead keratinized cells
Hard keratin- tough and durable
Chief parts:
-root, imbedded in skin
-shaft, projects above skin's surface |
|
|
Term
|
Definition
three concentric layers of keratinized cells.
-Medulla- central core
-cortex- surrounds medulla
-cuticle- outermost layer |
|
|
Term
|
Definition
infoldings of epidermis into dermis
Includes:
-hair bulb: deep, expanded end of hair follicle
-epithelial cells in center of bulb give rise to hair
-Root plexus: knot of sensory nerves around hair bulb |
|
|
Term
| what is the wall of hair follicles comprised of? |
|
Definition
both an epithelial component and connective tissue component
1. Connective tissue root sheath*
2. Epithelial root sheath* |
|
|
Term
| What is the arrector pili muscle? |
|
Definition
bundle of smooth muscle
-hair stands erect when arrector pili contracts |
|
|
Term
Where are sebaceuous glands?
What do they secrete?
What are they associated with? \Functions? |
|
Definition
occur over entire body, except palms and soles
Secrete sebum: oily substance
Associated w/hair follicle
Function to collect dirt, soften and lubricate hair and skin |
|
|
Term
What type of gland is a sebaceuous gland?
Why type of secretion? |
|
Definition
simple alveolar gland
holocrine secretion- entire cell breaks up to form secretion |
|
|
Term
Where are sweat glands? what are they aka?
What is sweat? What does it contain? |
|
Definition
Sudoriferous glands
Widely distrubuted on body
Sweat is a blood filtrate- 99% water, w/salts
Contains traces of metabolic wastes:
-nitrogen wastes, ammonia, urea |
|
|
Term
| What are the types of sweat glands? |
|
Definition
Eccrine gland- most numberous and produce true sweat
Apocrine gland- confined to axillary, anal, and genital areas
Produce special sweat |
|
|
Term
| What are the types of skin cancer? |
|
Definition
Basal cell carcinoma- least malignant and most common
Squamous cell carcinoma- arises from keratinocytes of stratum spinosum
Malanoma- a cancer of melanocytes (most dangerous type of skin cancer) |
|
|
