Integumentary System Quiz

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Questions and Answers

What is the primary function of the integumentary system?

Producing hormones

Providing mechanical protection (correct)

Facilitating muscle movement

Regulating blood circulation

Which layer of the epidermis contains dendritic cells responsible for immune functions?

Stratum Granulosum

Stratum Lucidum

Stratum Germinativum

Stratum Spinosum (correct)

What type of epithelial cells make up the epidermis?

Stratified squamous epithelial cells (correct)

Columnar epithelial cells

Simple cuboidal epithelial cells

Ciliated epithelial cells

Which accessory structure is primarily responsible for thermoregulation?

Sweat glands Signup and view all the answers

Which of the following substances is NOT excreted by the integumentary system?

Protein Signup and view all the answers

What is the role of melanocytes in the integumentary system?

Producing melanin for UV protection Signup and view all the answers

What is a characteristic feature of the stratum germinativum?

Undergoes rapid cell division Signup and view all the answers

How many layers does thick skin have?

5 layers Signup and view all the answers

What type of connective tissue primarily makes up the papillary layer of the dermis?

Areolar connective tissue Signup and view all the answers

What is the primary reason that the hypodermis is an effective site for slow absorption injections?

Low concentration of capillaries Signup and view all the answers

What is the structural component that surrounds and nourishes the hair follicle?

Papilla Signup and view all the answers

Which of the following statements about collagen and elastin fibers in the dermis is correct?

They are affected by aging and hydration status. Signup and view all the answers

What color progression is typically seen in a contusion (bruise) as it heals?

Black → Blue → Green → Yellow Signup and view all the answers

Which of the following describes terminal hair?

Thick and heavily pigmented Signup and view all the answers

Which term refers to the network of blood vessels found in the reticular layer of the dermis?

Cutaneous plexus Signup and view all the answers

Which of the following accessory structures is NOT rooted in the dermis but has an epidermal origin?

Nerves Signup and view all the answers

What type of burn is classified as full thickness?

3rd degree burn Signup and view all the answers

Which of the following symptoms is associated with a 1st degree burn?

Red skin and pain Signup and view all the answers

Which change associated with aging leads to increased susceptibility to infection?

Reduced immune cell numbers Signup and view all the answers

What is the primary reason why 3rd degree burns may require a skin graft?

Full thickness damage prevents self-repair Signup and view all the answers

What decreases by 75% as people age, impacting skin health?

Vitamin D production Signup and view all the answers

What is the primary function of keratohyalin in the skin?

It dehydrates cells and glues keratin fibers together. Signup and view all the answers

Which layer of the skin is specifically found in thick skin, such as that on palms and soles?

Stratum Lucidum Signup and view all the answers

In the Stratum Corneum, how many layers of cells are typically present?

15 to 30 Signup and view all the answers

What causes differences in skin color among individuals?

Genes, melanosome size, and their deposition layers. Signup and view all the answers

What is the main pigment produced by melanocytes in the skin?

Melanin Signup and view all the answers

How does the body synthesize calcitriol?

After cholesterol is converted to cholecalciferol in the skin. Signup and view all the answers

What characterizes lentigos compared to freckles?

Regular border and defective melanocytes. Signup and view all the answers

What distinguishes the Stratum Granulosum from other layers?

It is where keratinocytes begin to dehydrate and undergo keratinization. Signup and view all the answers

What is the role of sebum produced by sebaceous glands?

It inhibits the growth of bacteria. Signup and view all the answers

What triggers the activity of sweat glands during puberty?

Hormonal changes stimulated by the nervous and endocrine system. Signup and view all the answers

Which structure is formed by keratinization and cell division at the nail root?

Nail body Signup and view all the answers

What is the first tissue layer to be repaired when an injury occurs?

Dermis Signup and view all the answers

What is the purpose of macrophages during tissue repair?

They eat debris and pathogens. Signup and view all the answers

Which of the following statements about sebaceous follicles is accurate?

They directly secrete sebum onto the skin. Signup and view all the answers

What causes the white appearance of the lunula on a nail?

Low blood vessel density. Signup and view all the answers

What is the key component in the blood clot that restores physical integrity after an injury?

Fibrin fibers Signup and view all the answers

What is the main component of the cutaneous membrane that makes it resistant to water loss?

Keratin Signup and view all the answers

The stratum granulosum is the layer where cells are actively dividing.

False Signup and view all the answers

Name the layer of skin that is directly beneath the epidermis.

dermis Signup and view all the answers

The two main layers of the skin are the epidermis and the ______.

dermis Signup and view all the answers

Match the following functions of the integumentary system with their correct descriptions:

Protection = Prevents fluid loss and shields against pathogens Excretion = Removes waste products through sweat Sensation = Detects touch, temperature, and pain Production = Synthesis of Vitamin D and melanin Signup and view all the answers

Which of the following layers of the epidermis contains stem cells that divide to replenish the skin?

Stratum Germinativum Signup and view all the answers

The subcutaneous layer is considered part of the epidermis.

False Signup and view all the answers

The _______ layer of the skin is responsible for storing fat.

dermis Signup and view all the answers

What structure is primarily responsible for producing hair?

Hair follicle Signup and view all the answers

Which degree of burn involves the destruction of both the epidermis and dermis and may require a skin graft?

3rd degree Signup and view all the answers

The reticular layer of the dermis is primarily made up of areolar connective tissue.

False Signup and view all the answers

A 1st degree burn results in blisters forming between the epidermis and dermis.

False Signup and view all the answers

What type of connective tissue is found in the papillary layer of the dermis?

areolar connective tissue Signup and view all the answers

What happens to the number of immune cells in the skin as a person ages?

The number of immune cells decreases. Signup and view all the answers

The primary component of the dermis that provides strength and flexibility is ___.

collagen Signup and view all the answers

Match the accessory structures to their primary functions:

Hair follicles = Produce hair Sebaceous glands = Produce sebum Sweat glands = Regulate body temperature Nails = Protect tips of fingers and toes Signup and view all the answers

As people age, Vitamin D production decreases by _____%.

75 Signup and view all the answers

Match the types of burns with their characteristics:

1st degree = Epidermal damage only, red skin, painful 2nd degree = Epidermal and some dermal damage, blisters form 3rd degree = Destruction of both epidermis and dermis, may involve deeper structures Partial thickness = Includes 1st and 2nd degree burns Signup and view all the answers

Which layer of the skin is NOT part of the integument?

Hypodermis Signup and view all the answers

What is the primary characteristic of the stratum lucidum?

Flat and thin, transparent appearance Signup and view all the answers

The color of hair is determined solely by the structure of the hair follicle.

False Signup and view all the answers

Melanocytes are responsible for producing keratin in the skin.

False Signup and view all the answers

What is the immune response that occurs as a bruise heals?

color changes from black-blue to green to yellow Signup and view all the answers

What is the role of keratohyalin in the skin?

Dehydrates cells and glues keratin fibers together. Signup and view all the answers

In the skin, UV rays convert __________ to produce vitamin D.

cholesterol Signup and view all the answers

Match the following skin components with their functions:

Melanocytes = Produce melanin Keratohyalin = Gluing keratin fibers Stratum Corneum = Barrier against water loss Lentigos = Extra productive melanocytes Signup and view all the answers

Which layer of the skin is primarily responsible for the water-resistant properties?

Stratum Corneum Signup and view all the answers

Freckles have irregular borders and are a result of increased melanin production.

True Signup and view all the answers

What happens to cholesterol in the skin when exposed to UV rays?

It is converted to cholecalciferol (vitamin D3). Signup and view all the answers

What is the main function of sebaceous glands?

To inhibit bacteria growth and protect the hair shaft Signup and view all the answers

Sweat glands exclusively become active at puberty.

False Signup and view all the answers

What type of glands are mammary glands classified as?

Apocrine Signup and view all the answers

The area of low blood vessels at the base of the nail, which appears white, is known as the __________.

lunula Signup and view all the answers

Match the following types of glands with their characteristics:

Sebaceous Glands = Holocrine production of oil Sweat Glands = Merocrine and Apocrine classifications Mammary Glands = Produces milk Sebaceous Follicles = Dumps sebum directly onto skin Signup and view all the answers

Which process describes the initial response to a skin injury?

Stratum germinativum cells start dividing and migrate Signup and view all the answers

The blood clot primarily consists of muscle fibers.

False Signup and view all the answers

Where does nail cell division and keratinization primarily occur?

Nail root Signup and view all the answers

Study Notes

Integumentary System

Covers the exterior of the body
Composed of the cutaneous membrane (skin) and accessory structures
Cutaneous membrane is made up of the epidermis and dermis
Subcutaneous or hypodermis is deep to the cutaneous membrane
Accessory structures: Hair, hair follicles, sebaceous glands, sweat glands, nails, and sensory receptors.

Functions of the Integumentary System

Protection from mechanical injury, biological agents, and fluid loss
Excretion of salt, water, and organic wastes
Maintenance of body temperature
Production of melanin for UV protection, keratin for water resistance, and Vitamin D for calcium absorption
Storage of fat in the dermis and subcutaneously
Sensation of touch, temperature, pain, and vibration

Epidermis

Stratified squamous epithelial cells
Avascular - relies on diffusion from capillaries in the dermis
Cells divide at the basal lamina
Consists of keratinocytes

Layers of the Epidermis

Thin skin: 4 layers
Thick skin: 5 layers (found in palms and soles of feet)
Stratum Germinativum:
- Forms epidermal ridges that match the underlying dermal papillae, increasing surface area for grip
- Contains basal cells (stem cells) that divide and push up into the next cell layer
- Merkel cells for sensitive touch are found in hairless skin
- Melanocytes for melanin production are also present
Stratum Spinosum:
- Cells start becoming dehydrated, giving them a spiny appearance.
- Contains dendritic cells (immune function)
- Some cells divide and push up into the next cell layer.
- 8 to 10 cells thick.
Stratum Granulosum:
- No further cell division, but cells continue to be pushed up by cell division below.
- Produce keratin and keratohyalin to glue keratin fibers together.
- 3 to 5 cells thick.
Stratum Lucidum (found in thick skin only):
- Flat, thin cells with no organelles, filled with keratin, giving it a glassy appearance.
Stratum Corneum:
- Makes up all exposed skin except the anterior surface of the eyes.
- Composed of dead, keratinized cells.
- Tightly linked by desmosomes.
- 15 to 30 cell layers thick.
- Water resistant, but not waterproof.
  - Insensible water loss is due to the hypertonicity of air, resulting in a loss of 500 ml/day.
  - Sensible water loss (from sweat glands) varies depending on the individual, environment, and activity.

Melanocytes

Found in the stratum germinativum and extend up into the stratum spinosum (lighter skin) or stratum granulosum (darker skin).
Produce melanin: brown, black, or yellow-brown pigment packaged in melanosomes (small or large).
Melanocytes donate melanosomes to keratinocytes (ratio of 1:4 to 1:20 melanocytes: keratinocytes).
Skin color differences are due to genetics, size of melanosomes, layer of deposition, and number of melanosomes produced.
Freckles: irregular border, melanocytes are extra productive compared to others in the skin.
Lentigos: regular border, defective melanocytes due to sun exposure.
Function: protects the nucleus from UV radiation that can cause mutations in DNA.

Vitamin D

UV rays convert cholesterol in the skin to cholecalciferol (D3).
Cholecalciferol travels to the liver and is converted to an intermediary.
The intermediary travels to the kidneys, where it is used to synthesize calcitrol, which increases calcium and phosphate absorption from the digestive tract.

Dermis

Located between the epidermis and subcutaneous layer.
Consists of two layers:
- Papillary layer: areolar connective tissue, capillary network (papillary plexus), and neurons.
- Reticular layer: dense irregular connective tissue, neurons, capillary network (cutaneous plexus), and contains epidermal extensions (hair follicles, sweat glands, sebaceous follicles and glands, and nails).
Contains collagen and elastin fibers for flexibility and strength.
Contusion (bruise): rupture of small dermal blood vessels, turning black-and-blue, green, then yellow due to the immune response.

Hypodermis (Subcutaneous)

Not part of the integument.
Stabilizes the position of the skin.
Composed of areolar and adipose tissues, making it very elastic.
Superficial layer functions as a blood reservoir and aids in heat exchange.
Deeper layer has low capillary density, making it a good location for slow-release injections.

Accessory Structures

Located in the dermis but epidermal in origin.

Hair

Structure: hair follicle produces hair:
Extends from the surface of the epidermis deep into the dermis or hypodermis.
Contains a root plexus (nerves and blood vessels) at the base.
Arrector pili muscle attaches to the papillary layer of the dermis and connective tissue sheath surrounding the hair follicle.
**Hair root: **
- Bulb: around papilla (connective tissue with blood and nerves).
- Matrix: cells divide and are keratinized.
  - Medulla: center of hair shaft, contains soft keratin.
  - Cortex: middle of hair shaft, contains hard keratin.
  - Cuticle: outer edge of hair shaft, contains hard keratin.
Hair shaft:
Types:
- Lanugo: embryonic hair
- Vellus: peach fuzz
- Terminal: heavy with pigment, thick, can be curly
Hair color: due to melanocytes in the papilla. Color can change due to hormones, chemotherapy, and age.
- Dyes disrupt the cuticle, weakening the hair.

Sebaceous Glands

Holocrine production of sebum (oil).
Inhibits bacterial growth, protects the hair shaft, conditions the skin.
Associated with hair shafts.

Sebaceous Follicles

Not associated with hair shafts.
Dump sebum directly onto skin.

Sweat Glands

Merocrine:
- Found in armpits, groin, and nipples.
- Secrete onto hair follicles.
- Become active at puberty, stimulated by the nervous and endocrine systems.
Apocrine:
- Mammary glands.

Nails

Root: near bone, epithelial in origin, where cell division and keratinization take place.
Cuticle (eponychium): stratum corneum from the root that extends over the exposed nail.
Nail body: visible portion, over top of the nail bed.
Free edge: extends over the hyponychium (thickened stratum corneum).
Lunula: area of low blood vessels, appearing white.

Repair of Injury

Stratum germinativum in epidermis: cells begin dividing and moving along the edges of the injury, while macrophages clear debris and pathogens.
Mesenchymal cells and fibroblasts in connective tissue play a role in repair.
Blood clot: restores physical integrity, mostly fibrin fibers.
Dermis is fixed first: mesenchymal cells divide and differentiate, fibroblasts lay down collagen and ground substance.
Capillary growth follows fibroblasts (granulation tissue).
Epidermal cells migrate over the meshwork produced by fibroblasts.
Clot dissolves, capillaries retreat, and scar tissue is laid down.

Burns

Partial thickness: 1st and 2nd degree.
Full thickness: 3rd degree.
1st degree: epidermal damage only, red skin, painful.
2nd degree: epidermal and some dermal damage, blisters form between the epidermis and dermis, red skin, painful, may scar.
3rd degree: destruction of both the epidermis and dermis, may involve tendons and bones, relatively painless due to destroyed sensory nerves, cannot repair itself (requires a skin graft).
Impaired skin function leads to fluid/electrolyte imbalances, thermoregulation issues, and increased infection risk.

Changes Associated with Aging

Germinative cell activity declines and connections weaken, leading to increased susceptibility to injury and infection.
Reduced number of immune cells.
Vitamin D production decreases by 75%.
Melanocyte activity decreases, increasing the risk of sunburn.
Glandular activity decreases: less sebum (dry, scaly skin), less sweat (hyperthermia).
Blood flow decreases, making you feel cold even when you are not.
Dermis thins and elastic network decreases in size.
Repairs proceed more slowly, due to reduced blood supply and immune function.

Integumentary System

The Integumentary system is an organ system covering the body's exterior.
The cutaneous membrane (skin) is composed of the epidermis and dermis with the subcutaneous or hypodermis layer deeper.
Accessory structures include hair, hair follicles, sebaceous glands, sweat glands, nails, and sensory receptors.
The integumentary system is a major system of blood vessels, but they do not reach beyond the basement membrane of the epidermis.

Integumentary System Functions

Protects against mechanical injury, biological agents, and fluid loss.
Excretes NaCl, H2O, and organic wastes
Maintains body temperature.
Produces melanin for UV protection, keratin for water resistance, and vitamin D to aid Ca++ absorption.
Stores fat in the dermis and subcutaneous layer.
Detects touch, temperature, pain, and vibrations.

Epidermis

Composed of stratified squamous epithelial cells.
Avascular.
Cells divide at the basal lamina.
Epidermal cells are known as keratinocytes.

Layers of the Epidermis

Thin skin has 4 layers, while thick skin has 5 layers.
The layers of the epidermis from the basement membrane upward are:
- Stratum Germinativum:
  - Forms ridges that match the underlying dermal papillae, increasing surface area for grip.
  - Contains basal cells (stem cells) that divide and move up into the next layer.
  - Merkel cells extend into this region in hairless skin for touch sensitivity.
  - Contains melanocytes for melanin production.
- Stratum Spinosum:
  - Cells begin dehydration, giving them a spiny appearance.
  - Contains dendritic cells for immune function.
  - Some cells divide and move up into the next layer.
  - With 8 to 10 cell layers thick.
- Stratum Granulosum:
  - Cell division stops, but they are still pushed up by cell division from below.
  - Produces keratin (protein fiber) and keratohyalin (dehydrates cells and glues keratin fibers together).
  - With 3 to 5 cell layers thick.
- Stratum Lucidum:
  - Found only in thick skin like palms and soles.
  - Flat, thin, and lacking organelles, only keratin - appearing glassy.
- Stratum Corneum:
  - Covers all exposed skin except the anterior surface of the eyes.
  - Composed of all dead and totally keratinized cells.
  - Tightly linked by desmosomes.
  - 15 to 30 cell layers thick.
  - Water-resistant, not waterproof, with insensible water loss (500 mL/day) due to air's hypertonicity and sensible water loss (sweat gland-produced) varying based on the individual, environment, and activity.

Melanocytes

Carotene accumulates in the stratum corneum in those with low melanin levels.
Found in the stratum germinativum, extending up into the stratum spinosum (lighter skin) or stratum granulosum (darker skin).
Produce melanin, a pigment with shades of brown, black, or yellow-brown.
- Melanin is packaged in melanosomes (which can be small or big) and sent to keratinocytes (ratio of 1:4 to 1:20 melanocytes: keratinocytes, depending on the body part).
Differences in skin color are due to:
- Genes (378 genes we know of)
- Small vs. large melanosomes
- The layer melanosomes are deposited into (spinosum vs. granulosum).
- The number of melanosomes produced.
Freckles have irregular borders due to extra-productive melanocytes compared to others in the skin.
Lentigos have regular borders due to defective melanocytes caused by sun exposure.
Protects nuclei from UV radiation - which causes DNA mutations.

Vitamin D

UV rays convert cholesterol to cholecalciferol (D3) in the skin.
D3 travels to the liver, where it is converted to an intermediary form, then to the kidney and used to synthesize calcitrol.
Calcitrol increases the absorption of Ca++ and PO4-3 from the digestive tract.

Dermis

Located between the epidermis and subcutaneous layer.
Contains two layers:
- Papillary layer:
  - Composed of areolar connective tissue, a capillary network (papillary plexus), and neurons.
- Reticular layer:
  - Composed of dense irregular CT, neurons, a capillary network (cutaneous plexus), and contains epidermal extensions (hair follicles, sweat glands, sebaceous follicles and glands, and nails).
Collagen and elastin fibers are found throughout the dermis, providing flexibility and strength, and are affected by aging, hormones, hydration levels, etc.
Contusion(bruise):
- Rupture of small dermal blood vessels, turning black-n-blue → green → yellow (due to the immune response).

Hypodermis (Subcutaneous)

Not part of the integument.
Stabilizes the skin's position.
Consists of areolar and adipose tissues - very elastic.
Superficial layer acts as a blood reservoir and assists with heat exchange.
Deeper layer has low capillaries (ideal for injections meant for slow absorption).

Accessory Structures

Located physically in the dermis, but of epidermal origin.
Hair:
- The hair follicle produces hair.
- Extends from the epidermis's surface deep into the dermis or hypodermis.
- Has a root plexus (nerves & blood vessels) at its base.
- Includes the arrector pili muscle (attached to the papillary layer of the dermis and connective tissue sheath around the hair follicle).
- Contains a hair root:
  - Bulb around the papilla (Connective tissues with blood and nerves).
  - Bulb cells form a matrix: these cells divide and are keratinized, forming:
    - Center (medulla): contains soft keratin.
    - Middle (cortex), Edge (cuticle): contain hard keratin.
- Has a hair shaft.
- Types of hair:
  - Lanugo: embryonic hair.
  - Vellus: peach fuzz.
  - Terminal: heavy with pigment, thick, can be curly.
- Hair color is due to melanocytes in the papilla and changes due to hormones, chemotherapy, and age.
  - Dyes enter the cortex and sometimes even the medulla by disrupting the cuticle, making hair weaker.
Sebaceous glands:
- Produce oil (sebum) via holocrine secretion.
- Sebum inhibits bacterial growth, protects the hair shaft, conditions skin, and is associated with the hair shaft.
Sebaceous follicles:
- Not associated with hair shafts.
- Directly dump sebum onto the skin.
Sweat glands:
- Are merocrine.
- Secretion occurs onto hair follicles in the armpits, groin, and nipples.
- Become active at puberty and are stimulated by the nervous and endocrine systems.
Mammary glands:
- Are apocrine.
Nails:
- The root is near the bone (epithelial in origin), where cell division and keratinization occur.
- The cuticle (eponychium: epi = upon; onych = nail) is stratum corneum from the root extending over the exposed nail.
- The nail body (visible portion) is over the nail bed.
- The free edge extends over the hyponychium - a thickened stratum corneum.
- The lunula is an area with low blood vessels, appearing white.

Repair of Injury

The stratum germinativum in the epidermis: cells begin dividing and moving along the injury edges, with macrophages ingesting debris and pathogens.
Mesenchymal cells and fibroblasts in connective tissue: play a role in repair.
A blood clot restores physical integrity, primarily with fibrin fibers.
The dermis is fixed first: mesenchymal cells divide/differentiate, and fibroblasts lay down collagen and ground substance.
Capillary growth follows the fibroblasts (granulation tissue).
Epidermal cells migrate over the meshwork produced by fibroblasts.
The clot dissolves, capillaries retreat, and scar tissue is laid down.

Burns

First and second-degree burns are considered partial thickness.
Third-degree burns are full thickness.
First-degree burns:
- Epidermal damage only, resulting in red skin and pain.
Second-degree burns:
- Epidermal and some dermal damage, resulting in blisters forming between the epidermis and dermis, red skin, pain, and possible scarring.
Third-degree burns:
- Destruction of both the epidermis and dermis, possibly involving tendons and bones.
- Relatively painless due to sensory nerve destruction and unable to repair itself, requiring skin grafts.
Compromised skin function lead to fluid/electrolyte imbalances, thermoregulation issues, and increased susceptibility to infection.

Changes Associated with Aging

Germinative cell activity decreases, and connections weaken, making the skin susceptible to injury and infection.
Decreased number of immune cells.
Vitamin D production decreases by 75%.
Melanocyte activity decreases, making the skin more prone to sunburn.
Glandular activity decreases (less sebum = dry, scaly skin; less sweat = hyperthermia).
Blood flow decreases, leading to feelings of coldness even when the actual temperature is not cold.
The dermis thins, and the elastic network shrinks.
Repairs proceed slower due to reduced blood supply and immune function.

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Description

Test your knowledge on the integumentary system, including its structure, functions, and components such as the skin, hair, and glands. This quiz covers details about the epidermis, its layers, and the overall role of the integumentary system in protecting the body. Perfect for students studying human anatomy!