Integumentary System

Question 1

Skin facts
What percent of bodyweight
How thick

Answer 1

Body’s largest and heaviest organ
15% of bodyweight
1-2 mm thick

Question 2

What is the scientific name for skin?

Answer 2

Cutaneous membrane

Question 3

What lies beneath the dermis?

Answer 3

Subcutaneous membrane
(Hypodermis)

Question 4

6 skin functions

Answer 4

Resistance to trauma and infection
Other barrier functions
Vitamin D synthesis
Sensation
Thermoregulation
Non-verbal communication

Question 5

Epidermis
Structure, unique properties

Answer 5

Densely-packed keritanized, stratified squamous epithelium
Dead cells at the surface packed with tough keratin protein
Avascular
Contains sparse nerve endings
Highly mitotic: fastest reproducing cells in the body

Question 6

Epidermis
4-5 Strata (superficial to deep)

Answer 6

Stratum corneum
Stratum lucidum (only in thick skin)
Stratum granulosum
Stratum spinosum
Stratum basale

Question 7

Stratum corneum

Answer 7

Dead keratinocytes and keratin
Resistant to abrasion, penetration and water loss

Question 8

Stratum lucidum

Answer 8

Only found in thick skin
Contains keratinocytes packed with eladin (clear protein)

Question 9

Stratum granulosum

Answer 9

3-4 layers of keratinocytes
Keratin production!
Keratin combines with lipids to create waterproof barrier for skin
Keratinocytes begin to die here - lack oxygen needed for metabolism

Question 10

Stratum spinosum

Answer 10

Thickest layer (except in thick skin)
Keratinocytes begin to flatten out
Dendritic cells

Question 11

Dendritic cells

Answer 11

Type of white blood cell (macrophage) patrols the skin looking for invading organisms and material but more scout than destroyer

Question 12

Stratum basale
Structure, types of cells, function

Answer 12

Single layer of cells appearing cuboidal at first, become stratified squamous as they move through strata
Mitotic stem cells
Keratinocytes
Melanocytes
Tactile cells
Site for new skin cell production

Question 13

Mitotic stem cells

Answer 13

Divide to become keratinocytes

Question 14

Keratinocytes

Answer 14

Basic skin cells layered throughout the strata to form protective thickness of skin

Question 15

Melanocytes

Answer 15

Produce melanin which absorbs UV light and prevents it from going deeper.
All bodies have same number of melanocytes, they produce diff amounts of melanin

Question 16

Tactile cells

Answer 16

Attached to neurons in underlying dermis, allow for sensation

Question 17

Dermal papillae

Answer 17

Form the distinct line between the dermis and epidermis
Under the epidermal ridges like legos locking in place

Question 18

Dermis
Name the 2 layers

Answer 18

Papillary layer
Reticular layer

Question 19

Dermis
Papillary layer

Answer 19

Thin layer near dermal papillae
Consists of areolar connective tissue (abundant blood vessels)

Question 20

Dermis
Reticular layer

Answer 20

dense irregular connective tissue

Question 21

Hypodermis (subcutaneous membrane)
Functins
Structure

Answer 21

Binds skin to underlying tissue and structures
Has more areolar and adipose tissue than dermis
Highly vascular (provides thermoregulation)
Provides cushion

Question 22

Hair structure
General, then superficial to deep

Answer 22

Follicle - entire hollow tube around hair
Bulb - base of hair, only part that contains living hair cells
Root - remaining part of follicle under skin’s surface
Shaft - Exposed on skin’s surface

Question 23

Nail
Extension of what?

Answer 23

Stratum corneum

Question 24

Nail
Structure

Answer 24

Dead keratinocytes densely packed with parallel, hard keratin fibers

Question 25

Nail
Structure parts

Answer 25

Nail plate - visible bit
Nail root - embedded under skin
Nail matrix - consists of stratum basale, site for nail growth

Question 26

Cutaneous glands
2 types and their differences

Answer 26

Exocrine: use ducts to transport their products
Endocrine: use blood supply to transport their products

Question 27

Exocrine glands
Sweat glands
Found where?

Answer 27

Dermis

Question 28

Sweat glands
2 types

Answer 28

Merocrine
Apocrine

Question 29

Merocrine glands
Location - produce what substance

Answer 29

In the dermis all over the body. Most numerous glands!
Produce watery perspiration

Question 30

Perspiration contents

Answer 30

Water
Sodium Chloride
Potassium
Lactic Acid
Hydrogen Ions (contribute to acid mantle)

Question 31

Apocrine glands
Found where?
Release what?

Answer 31

Sweat glands that act as scent glands releasing pheromones
Found in:
Groin
Axilla
Areola
Stimulated in response to stress and sexual stimuli

Question 32

Apocrine gland ducts

Answer 32

Lead to nearby hair follicles rather than an independent sweat pore

Question 33

Sebaceous glands
Produce what?
Function
Common problem

Answer 33

Sebum
Keeps skin from becoming dry and brittle, makes hair shiny
Ducts usually open into a hair follicle, some directly to the surface.
Acne! Glands producing large amts of sebum that stick to skin cells and plug hair follicle trapping bacteria

Question 34

Ceruminous glands

Answer 34

Found only in external ear canal
Produce excretions that combine with sebum to form Cerumen (earwax)
Ducts lead directly to surface of skin
Cerumen functions:
Waterproof ear canal
Keeps eardrum pliable
Kills bacteria

Question 35

Mammary Glands

Answer 35

Located in breasts
Produce milk