Integumentary System Overview

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Questions and Answers

What is the deepest layer of the skin called?

Epidermis

Dermis

Epithelial layer

Subcutaneous layer (correct)

The epidermis is vascularized and contains blood vessels.

False

What is the primary function of melanocytes in the epidermis?

To produce melanin, which absorbs UV light and protects DNA.

The skin serves vital functions such as regulating body temperature, protecting the body, and ________ chemicals.

excreting and absorbing Signup and view all the answers

Match the following cell types with their functions:

Keratinocytes = Make keratin and waterproof sealant Melanocytes = Produce melanin to protect against UV light Langerhans cells = Engulf and destroy invaders through phagocytosis Sebaceous glands = Produce oil to lubricate skin and hair Signup and view all the answers

What is the primary function of hair on the scalp?

To protect from UV radiation Signup and view all the answers

The cuticle is the deepest layer of the hair structure.

False Signup and view all the answers

What type of cancer involves cells in the stratum basale?

Basal cell carcinoma Signup and view all the answers

Hair is made up of a root and a __________.

shaft Signup and view all the answers

Which of the following is NOT a function of hair?

Immune response activation Signup and view all the answers

Match the following types of skin cancer to their corresponding characteristics:

Basal cell carcinoma = Most common type of skin cancer Squamous cell carcinoma = Represents 20% of skin cancers Malignant melanoma = Cancers of melanocytes Signup and view all the answers

Wound healing is an essential part of maintaining integumentary homeostasis.

True Signup and view all the answers

The __________ layer of the hair consists of flat keratinized epithelial cells arranged like roof shingles.

cuticle Signup and view all the answers

How many strata make up the skin in high abrasion areas like palms and soles?

Five Signup and view all the answers

The stratum granulosum consists of living cells that actively divide.

False Signup and view all the answers

What structure in the dermis contains capillaries and is responsible for sensing touch?

dermal papillae Signup and view all the answers

The cells in the stratum spinosum contain _________keratin IFs.

thicker Signup and view all the answers

Match the strata of the skin with their characteristics:

Stratum basale = Contains stem cells and divides to replenish overlying strata Stratum corneum = Most superficial layer; dead cells slough off Stratum granulosum = Sealing layer with dying cells undergoing apoptosis Stratum lucidum = Found only in thick skin; provides mechanical support Signup and view all the answers

What is the main function of the stratum corneum?

Protection against abrasion Signup and view all the answers

Everyone has the same number of melanocytes regardless of skin color.

True Signup and view all the answers

What causes the formation of fingerprints?

epidermal ridges Signup and view all the answers

The _________region of the dermis is made of areolar connective tissue.

papillary Signup and view all the answers

Match the following epidermal features to their descriptions:

Melanin = A pigment responsible for skin color variation Keratin = A protein that provides strength to the skin Tyrosinase = An enzyme that assists in melanin synthesis Carotene = A pigment that can cause orange tinge to the skin Signup and view all the answers

What happens to skin when a tan fades?

Skin cells are replaced by cells with less melanin Signup and view all the answers

Tattoos typically fade quickly due to skin regeneration.

False Signup and view all the answers

What is the role of keratohyalin in the skin?

Aids in keratin intermediate filament assembly Signup and view all the answers

The dermis contains _________tissue that provides tensile strength.

connective Signup and view all the answers

Study Notes

### The Integumentary System

The integumentary system includes: skin, hair, nails, sweat glands, oil glands, and sensory receptors.
The skin is the largest organ, weighing roughly 7% of body weight.
Skin thickness varies, ranging from 0.5 mm on eyelids to 4 mm on heels.
The epidermis is the outer layer of skin and is avascular (lacks blood vessels).
The dermis, beneath the epidermis, is vascularized and composed of connective tissue.
The subcutaneous layer, or hypodermis, is the deepest layer, anchoring structures to the fascia and containing pressure receptors.

### Functions of the Integumentary System

Regulates body temperature.
Protects the body from external insults (e.g., abrasion, dessication, irradiation, and invasion).
Senses signals (e.g., touch, pain, temperature).
Excretes and absorbs chemicals.
Stores blood and energy.
Synthesizes vitamin D.

### The Epidermis

Composed of keratinized stratified squamous epithelium.
Contains various cell types, including:
- Keratinocytes: produce keratin, a protein that provides strength and waterproofing.
- Melanocytes: contain melanin, a pigment that absorbs UV light and protects DNA.
- Intraepidermal macrophages (Langerhans cells): phagocytes that engulf and destroy invaders.
- Tactile epithelial cells: sense touch and are in direct contact with tactile discs (nervous tissue).
Subdivided into strata, which are layers of keratinocytes at different stages of maturity.
Most of the body has four strata; palms and soles have five strata.

### Epidermal Strata (Deepest to Most Superficial)

Stratum basale: contains stem cells that replenish overlying strata and is rich in keratin intermediate filaments.
Stratum spinosum: provides strength and contains thicker keratin intermediate filaments.
Stratum granulosum: seals the epidermis and contains dying cells, releasing lipids to prevent fluid loss.
Stratum corneum: superficial layer composed of dead, sloughed-off cells.
Stratum lucidum: present only in thick skin, is clear and composed of dead, flat keratinocytes.

### Epidermal Growth

Takes 4-6 weeks for new cells from the stratum basale to reach the stratum corneum.
Keratinization reinforces skin by accumulating keratin in cells that die by apoptosis.
Cells farther from the stratum basale have reduced access to nutrients.

### The Dermis

Composed of connective tissue and provides tensile strength.
Divided into two regions:
- Papillary region: contains areolar connective tissue, dermal papillae (tissue extensions into the epidermis), and sensory nerve endings.
- Reticular region: contains dense irregular connective tissue, thick collagen fibers, and various cells.
Anchors the dermis to the subcutaneous layer.

### Fingerprints

Form from epidermal ridges that dig into the dermal papillae.
Unique to each individual, even identical twins.
Increase friction for grip and surface area for touch sensing.

### Skin Colour

Differences in skin colour are due to varying amounts of melanin produced by melanocytes.
A tan is a result of increased tyrosinase activity in melanocytes upon UV light exposure.
Tans fade as cells with high melanin levels are replaced by cells with normal melanin production.
Skin colour also influenced by carotene, a pigment stored in the stratum corneum, giving skin an orange tinge.

### Tattoos

Permanent because ink is deposited in the dermis, not the epidermis.
Removal involves laser treatment that destroys pigmented cells, followed by phagocytosis of the cell debris.

### Hair

Protects and insulates the body and aids in sensory perception.
Found on various parts of the body, including scalp, eyebrows, eyelashes, and genitalia.
Functions include trapping air for insulation and touch sensing through hair movement.
Consists of:
- Root: embedded in the dermis or subcutaneous layer.
- Shaft: superficial portion of the hair.
- Medulla (inner layer): contains pigmented cells.
- Cortex (middle layer): majority of hair structure.
- Cuticle (outer layer): flat keratinized epithelial cells resembling shingles.

### Hair Structures

Hair follicle: surrounds the hair root, with an outer epithelial layer and an inner layer called the hair matrix, where continuous cell division occurs.
Arrector pili: smooth muscle that attaches to hair follicles and contracts in response to cold or fear.
Sensory receptors: connected to hair movement, allowing for touch sensation.

### Skin Cancer

Basal cell carcinomas: involve cells in the stratum basale, most common and generally benign.
Squamous cell carcinomas: involve cells in the stratum spinosum, represent 20% of skin cancers.
Malignant melanomas: cancers of melanocytes.
Increased risk from excessive UV exposure.

### Nails

Protect the ends of fingers and toes.
Composed of hard, keratinized cells.
Consist of:
- Nail body: visible portion.
- Nail root: embedded in skin.
- Nail matrix: responsible for nail growth.
- Nail bed: attaches nail body to the skin.
New cells are constantly produced at the nail matrix, pushing older cells forward and causing growth.
Can be affected by nutrition, health, and medication.

### Wound Healing

Inflammation: initial response to damage, characterized by redness, swelling, heat, and pain.
Migration and proliferation: cells migrate to the wound site and proliferate to repair damaged tissue.
Remodeling: collagen fibers reorganize, strengthening the wound and restoring function.
Factors such as age, nutrition, and infection can impact wound healing.

### Burns

Damage to the skin caused by heat, chemicals, radiation, or electricity.
Classified according to the depth of damage:
- First-degree burns: affect only the epidermis, characterized by redness and pain.
- Second-degree burns: affect both the epidermis and dermis, causing blisters, pain, and swelling.
- Third-degree burns: destroy all layers of skin, resulting in charred or white appearance, numbness, and potential for infection.
Severe burns require immediate medical attention to prevent infection, dehydration, and other complications.

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Description

Explore the intricacies of the integumentary system, including its components such as skin, hair, and nails, as well as its vital functions like temperature regulation and protection from external insults. This quiz delves into the structure of the skin layers and their roles in maintaining overall health.