Anatomy- The Skin

Question 1

Name the layers of epidermis (epithelium). Hint: there is 5 layers.
C- cars are the B-best S-sport G-guys L-love

Answer 1

(1) C- corneum
(2) B- basale
(3) S- spinosum
(4) G- granulosum
(5) L- lucidum

Question 2

Provide the properties for each of the epithelium layer.

Answer 2

C- keratinised cell remnants(remains), thick, interdigitating(interlocking) plasma membrane.

B- Germinal layer, which contains prekeratin tonofilaments(known as intermediate filaments made up of structural cytoplasmic proteins)

S- early keratin synthesis, contains membrane bound organelles.

G- kerotohyalin(is a protein structure found in cytoplasmic granules) granules form filaments

L- Nuclei and organelles are disappearing, densely packed filaments in the amorphous(shapeless)matrix, there is dead cells containing dispersed keratohyalin.

Question 3

Give the characteristics of the epithelium. (4 marks) besides it’s layers.

Answer 3

It includes :
• keratinised stratified squamous epithelial cells ( meaning the cells of our skin are changed into a flat form having keratin(protein)).

• keratinocytes(epidermal cell) which create keratin
• melanocytes( melanin producing cells)which create skin pigmentation
• they are avascular, supported and nourished by the dermis(is the thickest layer of the skin and found between the epidermis and subcutaneous layer)

Question 4

Provide the five characteristics of dermis.

Answer 4

• are mostly connective tissue
• have 2 layers: papillary (loose) and reticular (irregular dense)
• rich innervation and vasculature
• mostly dense connective tissue
• firmly connected to epidermis

Question 5

The dermis has two layers, briefly describe each layer.

Answer 5

1. Papillary layer
   • Located on the upper dermal region
   • has peglike projections (dermal papillae)
   • contain papillary loops (nutrients)
   • contains sensory receptors (pain receptors & touch receptors)
   • papillary patterns are genetically determined (fingerprints)
2. Reticular layer
   • is the deepest skin layer
   • composed of irregularly arranged connective tissue fibers ( collagen- toughness of dermis, attract and bind water & elastic fibers- gives skin elasticity)
   • contains blood vessels, sweat glands & oil glands
   • has deep pressure receptors (lamellar corpuscles)
   • contains phagocytes, which prevent bacteria from penetrating deeper.
   • abundantly supplied with blood vessels- regulate body temperature.

Question 6

Name the 3 layers contained within the structure of the skin.

Answer 6

1. Epidermis
2. Dermis
3. Hypodermis

Question 7

Provide characteristics of the hypodermis.

Answer 7

• is the subcutaneous tissue

* contains of: loose connective tissue, fat cells,large blood vessels and nerves.

Question 8

List the major functions of the skin and relate these functions to it’s histological structure. Hint: 14 functions- 7 P’s , 2 R’s , 2 T’s , 1 F, 1 E ,1 S = Prest F

Answer 8

1. Protects against UV = melanin
2. Protects from mechanical damage = keratin ( toughness cells), fat cells ( cushion), pressure receptors (alert NS to damage)
3. Protects from chemical damage = keratin cells( impermeable), pain receptors (alert NS to damage)
4. Protects against UV radiation =melanin (melanocytes- protects against UV rays)
5. Protects against thermal damage = heat/cold/pain receptors
6. Protects against detection = water-resisting glycolipid and keratin
7. Prevent dehydration = keratinised layer
8. Resist bacterial infection = keratinised layer
9. Register stimuli = nerve endings
10. Thermoregulation = via sweat and sebum glands
11. Thermal regulation of body = heat loss (sweat glands, blood flushing into capillaries- radiate from skin surface) heat retention (not allowing blood to flush to cap beds)
12. Flexion lines = grooves on the surface, like fingerprint or knee
13. Excretion of urea and uric acid = in your perspiration out of sweat glands
14. Synthesis of Vit D = modified cholesterol molecules in skin converted to Vit D.

Question 9

List the different associated appendages of the list.

Answer 9

1. Hair and Hair follicles
2. Nails
3. Sweat ( sudoriferous) glands
4. Sebaceous (oil) glands

Question 10

A brief discussion of hair and hair follicles.

1. A hair produced by a hair follicle, consists__.
2. A typical hair has a ___,____and____and __and___.Hair color reflects the____ and kind of ____ present.
3. A hair follicle consists of ___and___derived from___. The base of the hair follicles ___with a __ that produces the hair. A hair follicle is ___and__.___ pull the follicles into an upright position, producing ____and propel___to the skin surface when they contract.
4. Except for hairs of the scalp and around eyes, hairs formed initially are____ hairs at puberty under the influence of ____darker terminal hairs appear in the___and the___.
5. The rate of hair growth varies in ___and with___and___. Differences in life span of hairs account for ___ on ____. Hair thinning reflects factors that____,____of hair follicles and a ____.

Answer 10

1. Of heavily keratinised cells.
2. Central medulla, a Cortex, an outer cuticle, root, shaft portions. Amount, melanin
3. Inner epithelial root sheath, an outer peripheral connective tissue sheath, dermis. A hair bulb, matrix. Richly vascularized, well supplied with nerve fibers. Arrector pilling muscles, goose bumps, sebum.
4. Fine vellus, axilla,genital region.
5. Different body regions, sex, age. Differences in length,different body regions. Lengthen follicular resting periods, age- related atrophy, delayed-action gene.

Question 11

Briefly discuss the nails.

Answer 11

• A nail is a scalelike modification of the epidermis that cover the dorsum of a finger(or toe) tip.
• With the actively growing region known as the nail matrix.

Question 12

Brief discussion of sweat(sudoriferous) glands.

Answer 12

Eccrine