Human Anatomy: Skin and Hair Structure Quiz

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Questions and Answers

What type of keratin are nails composed of?

Hard keratin (correct)

Fibrous keratin

Soft keratin

Elastic keratin

Which part of the hair is responsible for its growth?

Hair shaft

Arrector pili

Hair bulb (correct)

Hair cortex

What is the primary function of sebaceous glands?

To protect against UV radiation

To provide insulation through hair

To lubricate and oil the skin (correct)

To produce sweat for cooling

Which type of hair is characterized as fine and short?

Vellus hair Signup and view all the answers

What percentage of the body is covered with hair?

Everywhere except palms and soles Signup and view all the answers

Which layer of skin is primarily responsible for sensations such as touch and temperature?

Dermis Signup and view all the answers

What are the two main layers of the dermis?

Papillary and reticular Signup and view all the answers

Which pigment is considered the most important in influencing skin color?

Melanin Signup and view all the answers

The primary function of the epidermis is related to _____?

Protection Signup and view all the answers

What term describes the deeper layer of skin that contains collagen and elastic fibers?

Dermis Signup and view all the answers

Which type of tissue primarily makes up the epidermis?

Epithelial tissue Signup and view all the answers

What is the role of fibroblasts in the dermis?

Synthesize collagen and elastin fibers Signup and view all the answers

What does the term 'hypodermis' refer to?

The layer below the dermis Signup and view all the answers

Which cells of the immune system are primarily responsible for detecting pathogens?

Neutrophils and Macrophages Signup and view all the answers

What is the main function of interferons (IFNs) in the immune response?

Warn neighbouring cells of viral infection Signup and view all the answers

Which of the following cytokines is considered a key anti-viral protein?

Interferons Signup and view all the answers

What happens to neighbouring cells when they are exposed to interferons?

They establish an antiviral state Signup and view all the answers

Which type of cells primarily secrete interleukins?

T-lymphocytes and Macrophages Signup and view all the answers

How does a virus replication get inhibited in host cells?

By inducing active host proteins Signup and view all the answers

Which characteristic is true about interleukins?

They are synthesized and secreted quickly after infection. Signup and view all the answers

What role do TLRs play in the immune system?

They bind to components of microbes. Signup and view all the answers

What is the primary function of antibodies in the immune system?

To bind specifically to unique antigenic epitopes Signup and view all the answers

Which component of an antibody is responsible for binding the antigen?

Fab region Signup and view all the answers

Which type of immunity is characterized by rapid responses to a broad range of microbes?

Innate immunity Signup and view all the answers

What roles do T-cells play in the immune response?

They mediate cell-mediated responses Signup and view all the answers

Which of the following structures make up the skin, which is part of the innate immune system?

Different layers of the skin Signup and view all the answers

What determines the specificity of antigen binding in an antibody?

The Fab region's VH and VL sections Signup and view all the answers

Which of the following does NOT belong to the external defenses of the innate immunity?

Phagocytic cells Signup and view all the answers

What is a B-cell receptor (BCR)?

A membrane-bound antibody on a B-cell Signup and view all the answers

What is the most dangerous type of skin cancer mentioned?

Melanoma Signup and view all the answers

Which of the following is a characteristic used to recognize melanoma?

Border irregularity Signup and view all the answers

What is the primary role of T-cells in the immune system?

Part of the specific immune response Signup and view all the answers

Which component is NOT part of the innate immune system?

B-lymphocytes Signup and view all the answers

What type of immunity involves a time lag before responding to a pathogen?

Adaptive immunity Signup and view all the answers

Which of the following is a physical barrier in the immune system?

Skin Signup and view all the answers

What is the function of normal flora in the immune system?

Compete with pathogens for nutrients and space Signup and view all the answers

Which immune cells are primarily responsible for phagocytosis?

Neutrophils Signup and view all the answers

What is one component of the internal defenses in the innate immune system?

Inflammatory response Signup and view all the answers

Which of these is a characteristic of acquired immunity?

Development of memory Signup and view all the answers

What percentage of true sweat is composed of water?

99% Signup and view all the answers

Which type of sweat gland opens directly through pores?

Eccrine (merocrine) glands Signup and view all the answers

In which burn classification does blistering occur?

Second-degree burns Signup and view all the answers

What is a critical burn according to the rule of nines?

Over 10% of the body has third-degree burns Signup and view all the answers

Which of the following is NOT a type of sweat gland mentioned?

Sebaceous glands Signup and view all the answers

Study Notes

Integumentary System

The integumentary system includes skin, hair, fingernails, and sweat and oil glands.
The skin has multiple layers to protect the body, regulate temperature, and excrete waste.
The skin is the first barrier against harmful things, and keeps good things within the body.

Functions of Skin

Protection: Protects underlying tissues and organs.
Vitamin D synthesis: Synthesizes vitamin D with UV exposure.
Homeostasis: Helps regulate body temperature.
Sensory reception: Contains nerve endings for sensory input.

Epithelium: Layers and Cell Types

Stratum corneum: Top layer, composed of dead, flattened keratinized cells.
Stratum granulosum: Layer below, cells are flattening and organelles are deteriorating.
Stratum spinosum: Contains thick bundles of intermediate filaments.
Stratum basale: Bottom layer, stem cells actively divide forming more superficial layers.
Keratinocytes: Major cells in epidermis; produce keratin
Desmosomes: Cell junctions that connect keratinocytes.
Melanocytes: Produce melanin, a pigment that protects against UV light.
Langerhans' cells: Part of the immune system
Merkel cells: Sensory cells.

Dermis

Strong, flexible connective tissue; your "hide".
Contains fibroblasts, macrophages, mast cells, and WBCs.
Fiber types include collagen (strength), elastic (stretch), and reticular fibers.
Rich supply of nerves and vessels.
Two layers:
- Papillary layer (areolar connective tissue; dermal papillae).
- Reticular layers (network of collagen and reticular fibers).
Important in temperature regulation.

Appendages of Skin

Hair, hair follicles
Sebaceous (oil) glands
Sweat glands (sudoiferous)
Nails

Skin Appendages

Derived from epidermis, extending into the dermis.
Include; hair and hair follicles, sebaceous (oil) glands, sweat (sudoiferous) glands, nails

Fingerprints, Palmprints, Footprints

Dermal papillae create ridges in the epidermis.
They are elevated by the epidermal ridges.
Characterized by sweat pores
Genetically determined.
Flexion creases originate from dermal folding.
Fibrous structures provide strength and resilience to the skin.

Hypodermis

Also called superficial fascia.
Consists of fatty tissue (areolar tissue and adipose cells).
Stores fat and anchors skin.
Contains different patterns of fat accumulation.

Skin Color

Three main pigments:
- Melanin (most important, produced by melanocytes).
- Carotene (from carrots, yellow vegetables).
- Hemoglobin (contributes to light skin color).
Melanin granules are passed to keratinocytes in the stratum basale; digested by lysosomes.
Variations in color influenced by the amount of each pigment.

Nails

Of hard keratin.
Corresponds to hooves and claws.
Grows from nail matrix.

Hair and Hair Follicles

Present everywhere except palms, soles, nipples, and parts of genitalia.
Each hair has an arrector pili muscle (smooth muscle).
Contains hair bulb with epithelial cells and hair papilla (connective tissue).

Functions of Hair

Provides warmth.
Senses light touch.
Protects the scalp.
Consists of three concentric layers: medulla, cortex, and cuticle.

Types of Hair

Vellus (fine, short hairs).
Intermediate hairs.
Terminal (longer, coarser hairs).

Hair Growth

Averages 2 mm/week.
Active growth phase
Resting phase, hair is shed

Hair Loss

Thinning: Age related.
Male pattern baldness.

Hair color

Determined by the amount of melanin and how it's distributed.

Sebaceous (Oil) Glands

Located throughout the body except on palms and soles.
Produce sebum (oils) through holocrine secretion.
Sebum lubricates and conditions skin.

Sweat Glands

Cover entire skin surface, except nipples and parts of genitalia
Produce sweat (mostly water, salts).
Important for temperature regulation.
Humans are most efficient at sweating among mammals.

Types of Sweat Glands

Merocrine (or eccrine): Most numerous, open directly onto the skin surface.
Apocrine: Found in axillary, anal, and genital regions; ducts open into hair follicles.
Sweat has an odor due to organic compounds.
Modified apocrine glands include ceruminous (earwax), mammary (milk).

Disorders of the Integumentary System

Burns:
- Threat to life
- Catastrophic loss of body fluids
- Dehydration and shock
Infections: First-degree (epidermis only): Redness Second-degree (epidermis and upper dermis): Blisters Third-degree (full thickness): Destruction
Wounds: Direct contact, vector-borne

Skin Cancer

Skin cancer related to UV exposure and aging
Benign tumors (e.g., warts)
Malignant tumors:
Actinic keratosis
Basal cell carcinoma
Squamous cell carcinoma
Malignant melanoma (most dangerous, recognition A,B,C,D)

Immune System

A functional system, not an organ system
Includes; skin (physical barrier), lining of mucus membranes (physical barrier), secretions (tears, mucus, etc) antimicrobial, blood cells and vasculature (WBCs), bone marrow, liver (makes complement proteins), lymphatic system, and lymphoid organs (most tissues and resident immune cells).

Overview of Immune System

Innate: First line of defense, no time lag, not antigen specific, no memory
Adaptive: Second line of defense, lag period, antigen specific, development of memory

A Typical Immune Response

External defenses: Skin, mucous membranes, secretions prevent invading microbes from entering the body.
Internal defenses: Phagocytic cells, antimicrobial proteins, inflammatory response, natural killer cells, and complement work within the body to combat the invasion of microbes.

Innate vs Adaptive Immunity

Innate immunity: Rapid response; no time lag; not antigen specific; no memory
Adaptive immunity: Slower response; time lag; antigen specific; memory

Anatomical Barriers (Mechanical)

Skin: Physical barrier to pathogens and chemicals
Mucociliary escalator: Protects the respiratory tract.
Flushing actions: Fluids like saliva, tears, and urine wash away pathogens.

Anatomical Barriers (Chemical)

Skin secretions like sebum, sweat, and tears
Enzymes and other chemicals in bodily secretions can effectively inhibit pathogens
Stomach acid
Lysozyme

Anatomical Barriers (Biological)

Normal flora: Microbes in many bodily areas act as competition against incoming pathogens
Normal flora prevent or limit infection

Innate Immune System: Internal Defenses - Cellular

Neutrophils: Most abundant WBC; efficient phagocytes.
Monocytes/Macrophages: Migrate to tissues and phagocytose microbes; antigen presentation
Natural Killer (NK) Cells: Kill virus-infected cells and cancer cells.
Toll-like receptors (TLRs): Proteins that recognize and bind to pathogens or their components.

Innate Immune System: Internal Defenses – Extracellular

Cytokines: Signaling molecules secreted by immune cells to regulate the immune response.
Complement: a large number of plasma proteins that react with one another (C1 - C9).
Coagulation proteins: Mechanisms to stop bleeding after injury to blood vessels, complex pathway with platelets, coagulation factors, vitamin k.

Cytokines

Small signaling proteins.
Secreted by immune cells to regulate behavior of other immune cells.
Key regulators in both innate and adaptive immunity.
Key players: interferons, interleukins, tumor necrosis factor (TNF).

Immunoglobulins(Antibodies).

Produced by plasma cells.
Part of adaptive immunity.
Specific binding sites to unique antigenic epitopes.
Exist in two forms: soluble and membrane-bound (B-cell receptor).

Specific Response - Adaptive Immunity

Antibody-antigen relationship
Involves lymphocytes (B and T cells) and plasma cells
Basis of vaccines

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Description

Test your knowledge on the anatomy of skin and hair in this informative quiz. Explore key components such as keratin, sebaceous glands, and the layers of the dermis. Perfect for students and enthusiasts of human biology.