EAP Ch. 5 - The Integumentary System

Question 1

Integumentary system - consists of and primary function

Answer 1

Organ system made up of skin, hair, nails, glands (e.g. sweat glands), sensory receptors, and subcutaneous tissue (connects skin to muscle), which acts as a covering or barrier.

Question 2

Skin layers (list 3)

Answer 2

Epidermis (top) - made up of Stratum Germinativum (bottom) and Stratum Corneum (top) + Dermis (bottom)

Question 3

Epidermis - what type of tissue and most abundant cells

Answer 3

Top layer of skin. Made of stratified squamous keratinizing epithelial tissue. Most abundant cells are keratinocytes.

Question 4

Name the two main layers of the Epidermis + type of cells found in each and their primary functions

Answer 4

Stratum Germinativum (stratum basale): bottom layer of epidermis. Where mitosis (growth) of new keratin cells take place. Keratin cells synthesize defensins (peptides that are produced after injury). Also contains Merkel cells, which are receptors for the sense of touch. Vitamin D (activated by UV rays) stimulates production of cathelicidin (antimicrobial)
Stratum Corneum: outermost layer of epidermis. Made of keratin, which is mostly waterproof, left over from dead cells.

Question 5

Explain the cause of blisters vs calluses vs fingerprints

Answer 5

Blisters are caused by friction, which separates skin layers, allowing tissue fluid to collect. Calluses are caused by pressure, which makes mitosis in the Stratum Germinativum increase, creating a thicker epidermis.

Fingerprints come from the ridges where the keratinocytes are connected.

Question 6

Langerhans Cells - state where found and what they are/do

Answer 6

Found in epidermis. Mobile cells that phagocytize foreign material and bring them to lymphocytes (white blood cells).

Question 7

Melanocytes - state where found and what they do + what benefit/draw backs are associated with their function

Answer 7

Found in lower epidermis (S. Germ.) produce pigment called melanin, which is genetically regulated. Increases with UV exposure and creates a barrier that protects living S. Germ. and Langerhans from UV rays. Dark skin has more UV protection, but produces less Vitamin D as a result. Melanin also accounts for hair and eye color.

Question 8

Dermis - what type of tissue, what is produced, and what is the layer between it and the epidermis

Answer 8

Lower layer of skin. Made of an irregular type of fibrous connective tissue (areolar tissue). Fibroblasts produce collagen (strong) and elastin (recoils after being stretched). Where dermis and epidermis meet is the papillary layer, which nourishes both.

Question 9

Dermis

Hair follicles - describe the parts and what they do

Answer 9

Base is the dermal papilla, which is a little projection in the dermis layer, containing blood vessels. Above is the hair root, containing cells called the matrix, where mitosis takes place. New cells produce keratin, get their color from melanin, and then die and become incorporated into the hair shaft, which is pushed toward the surface of the skin. Attached to each hair follicle is a small, smooth muscle called the pilomotor, arrector pili muscle - when stimulated, makes our hair stand on end.

Question 10

Dermis

Nail follicles - describe the parts and what they do

Answer 10

Mitosis takes place in the nail root at the base of the nail and the new cells produce keratin (stronger than what is found in hair) and then die. The flat nail bed beneath the nail is the living epidermis and dermis.

Question 11

Dermis

Receptors - describe the senses they are for and the 2 types

Answer 11

Cutaneous senses of heat, cold, itch, and pain are free nerve endings and touch and pressure are encapsulated nerve endings - most found in dermis, though Merkel cells and some nerve endings are found in S. Germ. of epidermis). When receptors detect changes they send signals to the brain, which interprets the impulses as sensations.

Question 12

Dermis

Glands - what type of tissue and where found

Answer 12

Made of epithelial tissue. The exocrine glands of the skin have their secretory portions in the dermis.

Question 13

Dermis

Sebaceous glands - form and function

Answer 13

Duct open into hair follicles or directly to skin surface, and secrete sebum (lipid called oil). Fatty acids inhibit some bacteria growth and prevent the drying out of skin and hair that can lead to cracks that let in bacteria.

Question 14

Dermis

Ceruminous glands - location and function

Answer 14

Secrete cerumen (ear wax) into the ear canal

Question 15

Dermis

Sweat glands - name two types and location/function

Answer 15

Apocrine found in axillae (arm pit) and eccrine found in forehead, upper lip, palms, and soles especially. Mostly water and salt. Can loose a lot of body heat through water evaporation, but can also lead to dehydration

Question 16

Dermis

Blood vessels - name type found in dermis and function. What happens when blood flow is restricted?

Answer 16

Blood vessels: Arterioles are small arteries, and the smooth muscle in their walls permits them to constrict (close) or dilate (open). When warm = vasodilation, which increases blood flow. When cold = vasoconstriction, which decreases blood flow. Decubitus ulcer (bed sores) occur when blood flow is cut off to skin by pressure between bone and bed, for example.

Question 17

Subcutaneous tissue - type of tissue and location/purpose

Answer 17

Also called superficial fascia - made of areolar connective tissue and adipose tissue - connects dermis to muscle, and is a continuous layer like the skin.

Question 18

Subcutaneous tisue

Other than collagen and elastin, what are the 3 main type of cells and their purpose

Answer 18

Has collagen and elastin like dermis, but also many white blood cells to destroy pathogens and mast cells, produced in red bone marrow, which produce histamine, leukotrienes, and other chemicals that help bring about inflammation.

Adipocytes (fat cells) store excess nutrients as a potential energy source, provides insulation from the cold, contributes to appetite and insulin use, brown fat produces heat, and activates WBCs, and is a cushion

Question 19

Describe pro/con of subcutaneous tissue makeup compared to dermis. What is necrotizing fasciitis?

Answer 19

Has more tissue fluid than dermis, which allows both WBCs and pathogens to move easier.

Necrotizing fasciitis - inflammation of fascia is caused by a Strep. virus.

Question 20

Burns - describe 4 degrees

Answer 20

1st degree (superficial epidermis) - redness (erythema) caused by vasodilation, which brings more blood to the site

2nd degree (partial-thickness) - damaged cells release histamine (inflammation), which makes capillaries more permeable, so more plasma escapes and becomes tissue fluid - hence blistering.

3rd degree (full-thickness) - entire epidermis layer is burned away. May not be painful if receptors are destroyed. Without S. Corn. layer, living tissue is exposed and susceptible to infection and dehydration.

4th degree (dell full-thickness) - reaches underlying muscle tissue or bone

Question 21

Burns

Describe what Septicemia and Circulatory Shock are

Answer 21

Septicemia (when pathogens get into blood) or dehydration leading to circulatory shock (tissue fluid evaporates from the burned surface > more plasma pulled out of capillaries > blood volume and pressure decreases > heart failure due to lack of blood to pump)

Question 22

Skin Cancer - describe 3 types and how to prevent

Answer 22

Squamous cell carcinoma and basal cell carcinoma are most coon, confirmed by biopsy, and usually able to completely remove without metastasis.

Malignant melanoma begins in melanocytes (pigmented spot or mole called a nevus, which may metastasize very rapidly.

Sunscreen contains chemicals that block UV rays and prevent them from damaging the epidermis.

Question 23

Name 4 common skin disorders

Answer 23

Impetigo - bacterial infection of staph

Eczema (atopic dermatitis) - allergic reaction with a genetic component

Warts - caused by virus that causes cells to divide abnormally

Fever blisters (cold sores) - caused by herpes virus

Question 24

Describe how fungis on skin is unique

Answer 24

Fungie (called tinea) don’t need to break through skin to cause ringworm

Question 25

Describe 3 ways to administer medication via skin

Answer 25

Transdermal: patches that allow small but continue amounts of medication (since Strat. Corn. is so solid

Subcutaneous injection: moderate blood supply = moderate rate of absorption = predictable. Used for insulin.

Intramuscular injection: good blood supply = rapid absorption. Used for vaccinations.