10.0 Integument system

Question 1

what are the 3 major regions of the integument

Answer 1

Epidermis - outermost superficial region

Dermis - middle region

Hypodermis (superficial fascia) - deepest region

Question 2

what are the cells of the epidermis

Answer 2

• composed of kertainized stratified squamous epithelium
• 4 cell types and 4-5 layers

Keratinocytes: produce fibrous protein keratin

melanocytes: produce bown pigment melanin

langerhans cells: macrophages, part of immune system

merkel cells: function as touch receptors in association with sensory nerve endings

Question 3

what are the layers of the epidermis

Answer 3

dermis, stratum basale, stratum epinsosum, stratum granulosum, stratum corneum

Question 4

describe the stratum basale

Answer 4

• basal layer
• deepest epidermal layer, firmly attached to dermis
• consists of single row of youngest keratinocutes cells undergo rapid division, hence its alternate name stratum germinativum

*single layer of cells

Question 5

describe the stratum spinosum

Answer 5

aka prickly layer

• keratinocytes in this layer appear irregular in shape
• web-like system of intermediate filaments attached to desmosomes
• melanin granules and langerhans cells are abundant in this layer

*area where cells are aging

Question 6

where are melanocytes located

Answer 6

ONLY in basal layer

• have membrane proejctions that go into stratnum spinosum
• keratinocytes take up melanin granules

Question 7

what are the two types of granules in the stratum spinosum

Answer 7

keratohyaline granules: involved in cross linking keratin and cellular dehydration

*make tissue stronger by cross linking keratin

lamellar granules: waterproofing glycolipid grandules that are spewed into extracellular space

*main reason the skin is waterproof

Question 8

describe the stratum granulosum

Answer 8

*as cells go clsoer to skin go farther from nutrient soruce

• cells flatten, their nuceli, organelles begin to dsiintegrate
• accumulate keratohyaline granules and lamellar granules

- PMs thicken, cytosol proteins bind to inner membrane face and released lipids coats their external surfaces

• above stratum granulosum, the epidermal cells are too fat from dermal capillaries and die

*process thought of as toughening up

Question 9

what is the stratum lucidum

Answer 9

• celar layer
• thin trasnparent band superficial to stratum granulosum
• few rots of flat dead keratinocytes
• Oily layer that is the result of exocytosis of lamellar bodies

only in thick skin: palsm fo ahnds and soles of feet

**only in thick skin like palsm of hands and soles of feet, not elsewhere

Question 10

describe the stratum corneum

Answer 10

• horny layer
• outermost layer of keratinized cells (3/4 thickness of epidermid)

*most of epidermis is stratum corneum

• dandruff is the shingle-like remnants of the stratum corneum that shed from scalp and dry skin

functions include:

• > waterproofing (glycolipids)
• . protection from abrasion and penetration (keratin and thickcened plasma mem)
• rendering body less sensitive to biolgoical and chemical and physical assults

Question 11

what are the alyers of the epidermid

Answer 11

most superfisical -> deep

corneum, lucidum, granulosum, spinosum , basale

*come lets get sun burnt

*lucidim is only in thick skin like palsm and soles

Question 12

what is the dermis

Answer 12

• contains strong, flexible connective tissue
• cell ypes inclueL fibroblasts, macrophages, mast cells and WBC
• has two layers:
• > Papillary (loose areolar conencive tissues)
• > returcular layer (dense irregular)

Question 13

describe the appillary layer of the dermis

Answer 13

• areolar connective tissue (collagen and elastic fibers)
• sueprior surface contains Peg-like projections called dermal papillae
• dermal papillae contains: capillary loops, meissner corpuscles and free nerve endings

Question 14

describe the reticular layer of the dermis

Answer 14

• apporx 80% of the thickness of skin
• dense irregualr conenctive tissue
• collagen fibers add strength and resiliency

elastin fibers provide stretch recoil properties

Question 15

what is the hypodermis

Answer 15

• subcutaneous layer deep to the skin
• composed of adipose and areolar conenctive tissue
• blood vessles go through this layer bc has fat to keep them warm -> can reg temp by constriction when cold and promoting blodo flow when warm

Question 16

what causes variations in skin colour

Answer 16

3 pigments: melamin, carotene and hemoglobin

• Melanin:
  
  • yellow - black pigment responsible for dark skin colours
  • freckles and males are local accumulatoins of meanin in karatinocyttes
• Carotene:
  
  • yellow-orange pigment, most obvious in the palms and soles of feet
    
    • accumulates in corneum and hypodermis (high conc of fat)
• hemoglobin:
  
  • Reddish pigment responsible for the pinkish hue of the skin
  • *cyanosis due to poorly oxygenated blood (blueish purple)

Question 17

what are the 4 types of sweat glands

Answer 17

sudoriferous glands, ceruminous, mammary and sebaceous

Question 18

descibe sudoriferous sweat glands

Answer 18

2 typres

• Apocrine glands
  
  • viscous secretion (milky yellowish colour)
  • activity can be increased by sexual foreplay (axilla, perianal)
  • associated with hair follicle
• Eccrine (merocrine) glands
  
  • secretion of hypotonic filrate of the blood
  • helps to prevent overheating (all over but more in axilla)
  • coiled strucute with tube

Question 19

desrcibe the ceruminous gland

Answer 19

Secrete cerumen or earwax

thought to deter insects and block entry of foreign material

Question 20

describe mammary glands

Answer 20

specialized sweat glands that secrete milk

Question 21

describe sebaceous oil glands

Answer 21

• holocine oil secretion called sebum (made of colesterol, proteins, fats and salts)
• keeps hair and skin soft and pliable, inhibits growth of bacteria and fingu (ringworm)
• activated during puebrty when androgens begin torise
• acne caused by clogged sebaceous gland pore

Question 22

what are the functions of hair

Answer 22

􏰁 Alerting the body to presence of insects on the skin

􏰁 Guarding the scalp against trauma, heat loss and sunlight

􏰁 Eyelashes shield the eyes and nose hairs filter large particles

Question 23

what locations on the body do not have hair

Answer 23

Palms, soles, lips, nipples and portions of

the external genitalia

Question 24

describe the layers of the hair follicle

Answer 24

• a knot of sensory verve endings called bhiar follicle receptor or root hair plexus wraps around each hair bulb
• bending of hair stimulates these endings helping our hairs to act as sensitive touch receptors
• has a cuticle, medulla and cortex

Question 25

what is the hair papilla and the hair matrix?

Answer 25

Hair papilla - dermal tissue that protrudes into the hair bulb and has capillaries Hair matrix - actively dividing area that produces hair, as cells are pushed upward they become increasing keratinized and die

Question 26

what determines hair colour

Answer 26

- pigment made by melanocytes at the abse of the hair follice - blonde and red hair have only a small amount of eumelanin, also have pheomelanin - black hair is all eumelanin

Question 27

describe the stages of hair growth

Answer 27

- 3 step growth cycle 1. Growth stage * cells of matrix differentiate, keratinize and die * forms root sheath and shaft * scale: 2-6 years growth at 0.3mm/day rgowth rate 2. Resting stage * growth of hair stops, can last for 3 months on scalp 3. After resting stage * hair replaces and new growth stage

Question 28

what is alopecia

Answer 28

- patial or complete hair loss 0 results from genetic factors, aging, endocrine disorders, chemotherapy or skin disease

Question 29

describe Pattern baldness

Answer 29

- androgenic alopecia - genetically determines and sex influenced - delayed action gene that "switches on" in adulthood and changes the response of hair follicles to DHT Treat with: **minoxidil** (stim hair growth) and **finasteride**

Question 30

what is the structure of a nail

Answer 30

- modification of the epidermis made of hard ketatin - deeper layers of epidermis extend beneath the nail as **nail bed** - as nail cells become heavily keratinized the nail body slides distaly over the nail bed

Question 31

what are the fucntions of the integumentary system

Answer 31

1. Protection * chemical (low pH, glycolipid waterproofing), physical and mechanical barrier 2. Cutaneous sensation * sens external touch/pain 3. Body temp * reg by: BV constiction to keep warm, dilation to inc sweat gland secretions to cool 4. Metabolic functions * synthesis of vitamin D in dermal blood vessels 5. Blood reservoir * skin blood vessels store up to 5% of the bodys blood volume 6. Excretion * limited amounts of nitrogenous wastes are eliminated from body in sweat

Question 32

describe aspects of cutaneous sensation of the integumentary system

Answer 32

Cutaneous sensation * called exoreceptors bc they sense external touch and pain * **merket discs:** free nerve endings, caress and clothing * **meissners corpuscles:** sense light pressure, heat and pain, rapidly adapting * **pacinian corpuslces:** deeper alter to deep pressure bumps * **hair follicle receptor or root hair plexus**

Question 33

what is a carcinoma

Answer 33

Cancer derived from epithelial cells and includes those of the breast, prostate, lung and colon

Question 34

What is sarcoma

Answer 34

Cancer derived from connective tissue, ormesenchymal cells

Question 35

what are lymphoma and leukemia

Answer 35

Cancer derived from hematopoietic cells

Question 36

what is a germ cell tumor

Answer 36

Cancer derived from pluripotent cells

Question 37

What is a blastoma

Answer 37

cancer derives from embryonic tissue

Question 38

how does skin cancer develop

Answer 38

- most skin tumors are benign and do not metastasize - crucial risk factor for nonmelanoma skin cancers is disabling the p53 gene (tumor suppressor gene) - get one mutation, then two mutations, then 3, becomes invassive, if it gets into blood vessel can go to other areas of the body

Question 39

what are the 3 major types of skin cancer

Answer 39

1. Basal cell carcinoma 2. Squamous cell carcinoma 3. Melanoma

Question 40

what is basal cell carcinoma

Answer 40

- Least malignant and most common skin cancer - Stratum basale cells proliferate and invade the dermis and hypodermis - Can be cured by surgical excision in 99% of the cases - Slow growing and do not often metastasize

Question 41

what is squamous cell carcinoma

Answer 41

􏰀 Arises from keratinocytes of stratum spinosum 􏰀 Arise most often on scalp, ears and lower lip 􏰀 Grows rapidly and metastasizes if not removed 􏰀 Prognosis is good if treated by radiation therapy or removed surgically

Question 42

what is melanoma

Answer 42

- cancer of the melanocytes, is the most dangerous type of skin cancer because - \> highly metastatic - \> resistant to chemotherapy - treated by wide surgical excision and immunotherapy - chance of survival is poor if lesion is over 4mm thick

Question 43

what are the characteristics of melanoma

Answer 43

ABCD - A: Asymmetry; two sides of the pigmented area don’t match - B: Border is irregular and exhibits indentations - C: Color is black, brown, tan and sometimes red or blue - D: Diameter is larger than 6 mm (size of a pencil eraser)

Question 44

what are burns

Answer 44

- caused by heat, electricity, chemicals, light, radiation or friction - burns can be highly variable in terms of tissue affected, severity and resultant complication - muscle, bone blood vessel, dermal and epidermal tissue can all be damaged - pain is due to inury of nerves

Question 45

what is a first gree brun

Answer 45

- superficial thickness - depth: epidermis involvement cncial findings: erthema, minor pain, lack of blisters

Question 46

what is second degree burn

Answer 46

- partial thickeness - superfiscial - depth: superficial (papillary) dermis - clinical findings: blisters, clear fluid and pain

Question 47

what is a third degree burn

Answer 47

- partial thickness (deep) - depth: deep (retiruclar) dermis - whiter appearance

Question 48

what is a fourth degree burn

Answer 48

- full thickness - depth: epidermis, dermis and partial damage to subcutaneous fat, eschar formation and minial pain, requires grafts

Question 49

what is a fith degree burn

Answer 49

- subdermial - complete destruction of epidermis, dermis, subcutaneous fat and underlying tissue and possible fascia, bone or mucle - hard leather like eschar, purple fluid, no sensation (insensate)

Question 50

when is a burn considered critical

Answer 50

- Over 25% of the body has second-degree burns - Over 10% of the body has third-degree burns Third-degree burns on face, hands, or feet

Question 51

rule of 9s to calculate burn sevarity

Answer 51

legs: 9% anterior trunk: 18% arm: 4/12% head: 4 1/2^

Question 52

burns can be potentially fatal, describe pathology of first 24 hr after burn

Answer 52

- Hypothermia - Tissue/blood destruction and hemoglobin loss leadshypoxia - Glomerular filtration rate and urinary output reduced andmetabolic acidosis - Plasma loss of proteins 4-6 hours post injury results in reduced intravascular colloid pressure causing plasma fluid loss