Human Biology Chapter on Skin and Immune System

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Questions and Answers

Which gland produces sebum to lubricate the skin?

Sebaceous glands (correct)

Sweat glands

Mammary glands

Ceruminous glands

What type of hair is described as fine and short?

Coarse hair

Terminal hair

Vellus hair (correct)

Intermediate hair

Where do nails grow from?

Nail bed

Nail fold

Cuticle

Nail matrix (correct)

What is the approximate average growth rate of hair per week?

2 mm Signup and view all the answers

What component of hair is located at its core?

Medulla Signup and view all the answers

Which type of sweat gland is involved in preventing overheating and is found on the entire skin surface?

Eccrine glands Signup and view all the answers

What is the role of arrector pili muscles?

To cause hair to stand on end Signup and view all the answers

Which type of hair is typically longer and coarser?

Terminal hair Signup and view all the answers

What contributes to the color of hair?

Presence of melanin Signup and view all the answers

What role do neutrophils play when they encounter a pathogen?

They directly engulf and destroy pathogens. Signup and view all the answers

What is the primary function of interferons (IFNs)?

To act as key anti-viral proteins. Signup and view all the answers

How do interleukins function within the immune system?

They modulate the behavior of other immune cells. Signup and view all the answers

What happens to neighboring cells when a virus infects a cell and interferons are released?

They develop an antiviral state to inhibit viral replication. Signup and view all the answers

What triggers the synthesis and secretion of interleukins?

Rapidly occurring immune responses to various infections. Signup and view all the answers

What are the two distinct regions of the integumentary system?

Epidermis and Dermis Signup and view all the answers

Which layer of the skin is responsible for temperature regulation?

Dermis Signup and view all the answers

Which type of tissue primarily composes the epidermis?

Epithelium Signup and view all the answers

What role does melanin play in the skin?

Protection from UV light Signup and view all the answers

What is the primary characteristic of the dermal papillae?

They elevate the overlying epidermis. Signup and view all the answers

Which of the following correctly describes the hypodermis?

It is also known as the superficial fascia. Signup and view all the answers

What factor is primarily responsible for variations in skin color?

The amount of melanin produced Signup and view all the answers

Which type of skin cancer is considered the most dangerous?

Melanoma Signup and view all the answers

What characteristic is NOT part of the recognition for melanoma?

Color uniformity Signup and view all the answers

What type of immunity involves a lag period after the initial exposure to an antigen?

Acquired immunity Signup and view all the answers

Which component of the immune system is primarily responsible for phagocytosis?

Neutrophils Signup and view all the answers

What is a major function of the skin in the immune system?

Mechanical barrier against pathogens Signup and view all the answers

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

It consumes nutrients essential for pathogens. Signup and view all the answers

Which of the following statements about innate immunity is true?

It has no time lag. Signup and view all the answers

Which type of cell is primarily responsible for the humoral response in acquired immunity?

B-lymphocytes Signup and view all the answers

What is the primary function of complement proteins in the immune system?

To assist in the destruction of pathogens Signup and view all the answers

What is the first line of defense in the immune system?

Innate immunity Signup and view all the answers

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

To find, eat, and digest microbes Signup and view all the answers

Which of the following is contained within the granules of neutrophils?

Lysozyme Signup and view all the answers

What happens to monocytes after they migrate into tissues?

They become macrophages Signup and view all the answers

What is a key role of natural killer (NK) cells?

Kill virus/bacteria infected cells and cancer cells Signup and view all the answers

What do Toll-like receptors (TLRs) primarily do in the innate immune system?

Bind to microbes and trigger immune responses Signup and view all the answers

What type of proteins are cytokines in the immune system?

Signaling molecules Signup and view all the answers

What type of cells are considered 'Big eaters' in the immune system?

Macrophages Signup and view all the answers

Which statement describes the activity of NK cells?

They release granules containing perforins Signup and view all the answers

What characterizes the innate immune response?

It comes into action when external defenses are breached Signup and view all the answers

Which cells are primarily responsible for antigen presentation in the immune system?

Macrophages Signup and view all the answers

Study Notes

Integumentary System

The integument includes skin, hair, fingernails, sweat and oil glands.
Skin has multiple layers protecting the body, regulating temperature and excreting waste.
The skin acts as the first barrier, preventing harmful substances from entering while keeping good substances in.
It is composed of two distinct regions: epidermis and dermis.

Functions of Skin

Protection
Synthesizes vitamin D with UV.
Homeostasis
Sensory reception (nerve endings)

Epithelium: Layers

Stratum corneum: dead cells filled with keratin; glycolipids create water resistance.
Stratum granulosum: flattened cells with deteriorating organelles and granules (lipids/keratohyaline).
Stratum spinosum: cells with bundles of pre-keratin filaments.
Stratum basale: actively dividing stem cells; some become superficial layers.
Melanocytes: produce melanin, a pigment.
Langerhans' cells: part of the immune system.
Merkel cells: sensory nerve endings.

Dermis

Strong, flexible connective tissue.
Cells: fibroblasts, macrophages, mast cells, WBCs.
Fiber types: collagen, elastic, reticular.
Rich supply of nerves and vessels, critical for temperature regulation.
Two layers: papillary and reticular.
- Papillary: areolar connective tissue, dermal papillae.
- Reticular: network of collagen and reticular fibers.

Skin Appendages

Derived from epidermis but extend into dermis.
Hair and hair follicles.
Sebaceous (oil) glands.
Sweat (sudoiferous) glands.
Nails

Fingerprints, Palmprints, Footprints

Dermal papillae lie atop dermal ridges.
These ridges elevate overlying epidermis.
Results in "sweat films" from sweat pores.
Genetically determined.
Flexion creases formed from continual folding within the dermis.
The dermis is the receptive site for the pigment of tattoos.

Hypodermis

"Hypodermis" (Greek) = below the skin.
"Subcutaneous" (Latin)=below the skin.
Also referred to as superficial fascia.
Fatty tissue (areolar tissue and adipose cells).
Stores fat and anchors the skin.
Different patterns of accumulation for males/females.

Skin Color

Three primary pigments: melanin, carotene, hemoglobin.
Melanin produced by melanocytes, amount and type determine skin tone.
Carotene from carrots and veggies affects skin color.
Hemoglobin in blood vessels gives skin a pinkish tone.
Melanin granules travel from melanocytes to keratinocytes to determine skin color.

Skin Disorders: Burns

Threat to life due to catastrophic loss of body fluids, dehydration, and circulatory shock.
Infection is a concern.
First degree burns: redness (e.g., sunburn).
Second degree burns: epidermis and upper dermis; blistering.
Third degree burns: full thickness.
Infections and wounds can also impair the skin's ability to heal.
Skin cancer is also a concern.

Tumors of the Skin

Benign tumors (e.g., warts).
Cancer: associated with UV exposure.
- Types: Aktinic keratosis, basal cell, squamous cell, melanoma (melanocytes; most dangerous).
- Recognition factors for skin cancer: Asymmetry, border irregularity, colors, and diameter greater than 6 mm.

Immune System

A functional system, not an organ system.
Complex system incorporating skin, mucous membranes, secretions, blood cells, vasculature (WBCs), bone marrow, liver (complement proteins), lymphatic system, and lymphoid organs.
Most tissues have resident immune cells.

Innate Immunity vs Adaptive Immunity

Innate—no time lag, not antigen specific, no memory.
Adaptive—lag period, antigen specific, development of memory.

Anatomical Barriers: Mechanical Factors

Skin: physical barrier.
Mucociliary escalator: expels foreign materials.
Flushing action: saliva, tears, and urine rinse microbes and foreign materials mechanically.

Anatomical Barriers: Chemical Factors

Antimicrobial peptides in sweat and other secretions.
Lysozymes in tears and saliva are enzymes that damage microbial cell walls.
Stomach acid and other stomach secretions break down foreign materials and kill pathogens.

Anatomical Barriers: Biological Factors

Normal microbiota: microbes naturally found on body surfaces.
Normal flora competes with pathogens for nutrients and space, making the environment less hospitable for them.

Innate Immune System: Internal Defenses - Cellular Components

Neutrophils: most abundant white blood cells, efficient phagocytes, crucial for innate immunity.
Monocytes/Macrophages: monocytes migrate into tissues becoming macrophages which phagocytose microbes in tissues.
Natural killer (NK) cells: kill virus/bacteria infected cells and cancer cells part of innate immunity.

Innate Immune System: Internal Defenses - Extracellular Components

Cytokines: small signalling proteins secreted by immune cells, influencing other cell behavior.
Complement proteins: a set of plasma proteins that interact in a cascade and function in activating immune cells and disrupting cell membranes of pathogens.
Coagulation Proteins: a pathway involving platelets, coagulation factors and Vitamin K; stops bleeding after any damage to blood vessels.

Toll-like Receptors (TLRs)

Transmembrane proteins present on macrophages and some other cells.
Conserved across vertebrates.
They are an important part of innate immunity and look out for microbes (or their components)
They bind to microbes and trigger a cascade of events to kill or protect against pathogens.

Cytokines

Small proteins secreted by cells of the immune system.
Affect the behavior of other cells.
Signaling molecules.
Key players in innate and acquired immunity: examples—interferons, interleukins, TNF.

Antibodies

Produced by plasma cells (B lymphocytes).
Essential part of adaptive immunity.
Specifically bind unique antigenic epitopes (antigenic determinants).
Possess antigen-binding sites for targeting specific antigens.
Members of the immunoglobulin protein class.
Exist in two forms: soluble (in blood and tissues) and membrane-bound (B-cell receptor: BCR).

Specific Response

Antigen-antibody relationship; vaccination.
Involves lymphocytes (B, T) and plasma cells.

Key Points Summary

Integumentary system—skin and its appendages.
Skin structure; critical for defense and homeostasis.
Immune system—functional components.
Innate and adaptive immunity.

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Description

Test your knowledge on skin anatomy and the immune system with this quiz. Questions cover aspects such as hair types, gland functions, and immune responses. Perfect for students studying human biology or related fields.