Chapter 5 - The Integumentary System

Question 1

Define the integumentary system

Answer 1

Organ system that includes skin, hair nails, glands, sensory receptors, subcutaneous tissue below the skin.

Question 2

What is the epidermis?

Answer 2

Outer skin made of Stratified squamous keratinizing epithelial tissue.

Question 3

What is a keratinocyte?

Answer 3

Cells that are abundant in the epidermis. No capillaries present between them. Bound together in “tight junctions” of proteins of their cell membranes

Question 4

What are defensins?

Answer 4

Antimicrobial peptides created by keratinocytes - produced after injury to the skin - rupture membranes of pathogens that may enter by ways of breaks in the skin

Question 5

What vitamin does the epidermis produce?

Answer 5

Vitamin D on exposure to UV light –?modified by liver and converted by kidneys o its most active form 1,25_D

Question 6

What is Vitamin D used for?

Answer 6

Important for absorption of calcium and phosphorus from food in the small intestine –? used to build the matrix of bones and teeth.

Question 7

What is Cathelicidin

Answer 7

a natural antimicrobial that punctures the membranes or outer covers of pathogen –? created by vitamin D that stimulates skin cells and white blood cells.

Question 8

What is the Stratum Corneum?

Answer 8

Outermost epidermal layer, consists of many dead cells, all that is left is their keratin

• relatively waterproof cell, prevents most evaporation of body water
• Barrier to chemicals and pathogens

Question 9

What is the Stratum germinativum?

Answer 9

• Contentious mitosis produces new cells to replace worn off surface cells
• produces antimicrobial definsins
• Cholesterol changed to Vitamin D on exposure to UV rays

Question 10

Describe Langerhans Cells

Answer 10

Also called dendritic cells (d/t branched appearance when they move)

• Originate in red bone marrow, mobile.
• Able to phagocytize foreign material (bacteria that enters body through skin breaks)
• Langerhand cells migrate to lymph nodes and present the pathogen to lymphocytes –> triggers an immue response.

Question 11

Describe 1st degree burn

Answer 11

only the superficial epidermis is burned (not blistered)
-skin will appear red (erythema) d/t vasodilation in the damaged area –> inflammatory response bring more blood to injured site

Question 12

Describe 2nd degree burn

Answer 12

• Partial thickness burn, deper layers of epidermis are affected.
• Damaged cells release histamine with infection, makes capillaries more permeable. , often creates blisters d/t fluid build up

Question 13

Describe 3rd degree burn

Answer 13

full thickness burn, entire episdermis charred away. Can be potentially life threatening.

Question 14

Describe 4th degree burn

Answer 14

qdepp full thickness burn - burn has reached underlying muscle tissue or bone. Bacterial infection is a serious problem

Question 15

What are Merkel Cells

Answer 15

Receptors for sense of touch

Question 16

Define Spticemia

Answer 16

When pathogens get into blood and spread through out body via bacterial infection (result of burns)
Define circulatory shock

Question 17

Define circulatory shock

Answer 17

As tissue fluid evaporate d/t burn, more plasma is pulled from capillaries into the tissue spaces, as more plasma is lost, blood volume and pressure decrease resulting in circulatory shock.
Define Melanocytes

Question 18

Define Melanocytes

Answer 18

Found in lower epidermis, produce melanin (made from amino acid tyrosine)

• People with dark skin, melancocytes continuously
• Melanin also gives color to hair. produce large amounts of melanin. (light skinned people produce less)
• melanin production ^ by exposure of skin to UV rays

Question 19

Define Squamous Cell carcinoma/ Basal cell carcinoma

Answer 19

Most common forms of skin cancer - lesions are visible as changes in normal appearance of skin, ix via biopsy.
-usually do not metastasize rapidly.

Question 20

Define Malignant melanoma

Answer 20

More serious form of skin cancer, begins in melanocytes. Serious because it may metastasize rapidly to lungs, liver or vital organs.

Question 21

What is the Dermis?

Answer 21

Irregular type of fibrous connective tissue (fibers are not parallel but criss-cross and run in all directions)

Question 22

What are Collagen / Elastin fibers

Answer 22

Produced by fibroblasts
-Collagen are strong,
-Elastin are able to recoil after being stretched.
Both characteristics of dermis (strength + elasticity)

Question 23

Define the Paillary Layer

Answer 23

Uneven junction of the dermis with the epidermis.
-Capillaries are abundant

Question 24

Define structure of Hair Follicles

Answer 24

Made of epidermal tissue

• Base of follicle is dermal papilla (projection of connective tissue of the dermis, contains blood vessles)
• Next is the hair root (contains cells called the matrix, where mitosis takes place) –> produces new keratin, get color from melanin, then die and incorporate into Hair shaft, which is pushed toward the skin surface.
• 0.3-0.4 inch of hair growth per month.

Question 25

Define structure of nail follices

Answer 25

Produce nails, mitosis takes place in nail root at bas of nails --\> new cells produce keratin tyheen die. -Nail consitts of kertinized dead cells, flat baed is living epidermis and dermis.

Question 26

Name an autoimmune disease of the skin

Answer 26

Alopecia Areta - hair is lost in discrete patches (usually on scalp) -Some form of psoriasis are thought to have an autoimmune component

Question 27

How do Receptors work?

Answer 27

- most receptors for cutaneous senses are found in the dermis (Merkel cells in Stratum germinativum) - Cutaneous senses: touch, pressure, heat, cold, itch, pain. --\> Cold itch pain receptors are free nerve endings - -\>touch and pressure are encapsulated nerve endings

Question 28

What are Sebaceous Glands?

Answer 28

- Epithelial tissue - open into hair follicles or directly to skin surface - -secrete sebum (lipid substance (oil) that inhibits growth of some species of bacteria on skin surface. - overactive sebaceous glands can lead to acne

Question 29

What are Cercuminous Glands?

Answer 29

- Located in dermis of ear canals - Secrete cerumen (earwax) - Prevents drying - Can become impacted if too much accumulates

Question 30

Define Sweat glands (2 types)

Answer 30

1) Appocrine - Most numerous in the axillae (underarm) and genital areas, most active in stressful and emotional situations. 2) Eccrine - all over the body (lots on forehead, upper lip, palms, soles) - sweat mostly water, made from blood plasma, is salty - Secrete to tube of dermis, extends to skins surface and opens into a pore. - Maintenance of body temp

Question 31

What is impetigo

Answer 31

Common skin disorder, bacterial infection cause by streptococci or staphylococci, -Characterized by pustules.

Question 32

What is Eczema?

Answer 32

Sx of atopic dermatitis --\> allergic reaction with genetic component that changes the chemistry and structure of the skin. -Results in itchy rash (pruritus), may blister or ooze, flare-ups triggered by allergens.

Question 33

Define Warts

Answer 33

Cause by virus that makes epidermal cells divide abnormally, producing growth that is raised and rough or pitted surface.

Question 34

What are Fever Blisters (cold Sores)?

Answer 34

Caused by herpes simplex virus, most people are exposed to as children. May be active lesion (usually at edge of lip). Painful, oozes. Can lay dormant if not destroyed by immune system.

Question 35

What are Arterioles?

Answer 35

Small arteries (smooth muscle in walls permits them to constrict or dilate) --\> important in maintenance of body temp. - -?In warm environments, the arterioles dilate, ^ blood flow through the dermis, brings excess heat close to body to be radiated to environment. - -\> in cold environment, they constrict to decrease blood flow through the dermis, keeping heat within core of body.

Question 36

What is subcutaneous tissue (superficial fascia)?

Answer 36

One of the connective tissue membranes, made of areolar connective tissue and adipose tissue --?connects dermis to underlying muscles. -contain collagen + elastin fibers and WBC's

Question 37

What are mast cells? Why do they work?

Answer 37

Produced in red bone marrow, found in connective tissue throughout the body --?produce histamine, leukotrienes and other chemicals to help bring about inflammation.

Question 38

Why are adipocytes important?

Answer 38

Cells of adipose tissues specialized to store fat --? helps cushion bony areas (like hip bones), provides some insulation from the cold. -Contributes to appetite, use of insulin, produces cytokines that activate WBCs

Question 39

Why is Areolar connective tissue important?

Answer 39

Connects skin to msucles, -Contains many WBCs to destroy pathogens -Contains mast cells What is necrotizing Fasciitis

Question 40

What is nercotizing Fasciitis?

Answer 40

An acute infection requiring surgical removal of the infected tissues, or even amputation of the limb. -Very serious, bodys defenses have been overwhelmed d/t looseness of areolar connective tissues.

Question 41

What affects does aging have on the integumentary system?

Answer 41

-both layrers of skin become thinner and more fragile (mitosis in the epidermis slows, fibroblast in the dermis die) -Sebaceous glands and sweat glands become less active - skin becomes dry, temperature regulation becomes more difficult -Hair follicles become inactive on the scalp ((baldness often genetically regulated) -Melanocytes dies are are not replaced (hair becomes white) -Skin more susceptible to sun burn (melanocyttes not enough to create efficient barrier of melanin) -Decreased ability to produce vitamin D