Exam #2 A&P

Histology & The Integumentary System

Integumentary System

Consists of the skin and its accessory structures, including hair, nails, and glands.

Epidermis

The outermost layer of skin, composed of keratinized stratified squamous epithelium.

Dermis

The layer of skin beneath the epidermis, containing loose connective tissue and dense irregular connective tissue.

Hypodermis

Also known as the superficial fascia or subcutaneous fat; it anchors the skin to deeper structures. not a layer of skin! very vascular and composed of adipose and loose connective tissue.

Sebaceous gland

Glands that produce oily sebum to waterproof and lubricate the skin.

cellulite

A dimpled appearance of the skin caused by fat deposits pushing through the connective tissue beneath the skin, usually occurring in areas such as thighs and buttocks.(not a disorder)

Sweat gland

Glands that produce sweat for thermoregulation and excretion of waste.

Sensory receptors

Detect heat, cold, pain, and pressure in the skin.

Arrector pili muscle

Small muscles associated with hair follicles; cause hair to stand up (goosebumps).

Thermoregulation

The process of maintaining a stable internal body temperature.

Vitamin D synthesis

The process that occurs in the skin, where UV light converts dehydrocholesterol to vitamin D3.

Keratinocytes

The primary cell type in the epidermis that produces the protein keratin.

Melanocytes

Cells in the epidermis that produce melanin, the pigment responsible for skin color.

Dendritic cells

Immune cells located in the skin that protect against pathogens.

Tactile cells

Sensory receptors in the skin that detect light touch.

Stratum corneum

The outermost layer of the epidermis, consisting of dead, flattened keratinized cells.

Stratum lucidum

A clear layer of dead skin found only in thick skin areas.

Stratum granulosum

A layer of the epidermis where keratinization begins.

Stratum spinosum

Layer of the epidermis where keratinocytes are interconnected by desmosomes.

Stratum basale

The deepest layer of the epidermis, where cell division occurs.

Papillary layer

The upper layer of the dermis, which contains loose connective tissue and dermal papillae.

Reticular layer

The denser, deeper layer of the dermis; contains collagen and elastin fibers.

Melanin

The pigment produced by melanocytes that provides skin color and protects against UV damage.

Erythema

Redness of the skin often caused by increased blood flow.

Pallor

Paleness of the skin due to decreased blood flow.

Cyanosis

A bluish coloration of the skin due to low oxygen levels in the blood.

Jaundice

A yellowish coloration of the skin, often due to liver conditions.

Freckle

A small area of increased pigmentation due to melanin production.

Mole (nevus)

An area of increased pigmentation due to proliferation of melanocytes.

Albinism

A genetic condition characterized by the absence of melanin production.

Acne vulgaris

A skin condition that arises from an accumulation of sebum and dead cells in sebaceous glands.

First-degree burn

A burn affecting only the epidermis, causing redness and minor pain.

Second-degree burn

A burn affecting the epidermis and part of the dermis, causing blisters.

Third-degree burn

A burn that extends through the epidermis and dermis, affecting deeper tissues.

Basal cell carcinoma

The most common type of skin cancer, arising from keratinocytes in the stratum basale.

Squamous cell carcinoma

Skin cancer arising from keratinocytes in the stratum spinosum.

Malignant melanoma

A serious type of skin cancer that originates from melanocytes and can metastasize.

ABCDE rule

A guideline for identifying suspicious moles (Asymmetry, Border, Color, Diameter, Evolving).

Hair bulb

The base of the hair follicle where hair growth occurs through mitosis.

Hair follicle

The structure from which hair grows; includes epithelial and dermal root sheaths.

Cuticle (hair)

The outermost layer of the hair shaft, made of overlapping keratinized cells.

Cortex

The middle layer of hair, providing strength and color.

Medulla

The innermost layer of hair, composed of soft keratin.

Hair shaft

The visible part of the hair that extends above the skin surface.

Nail plate

The hard protective covering of the fingertip.

Lunula

The visible part of the nail matrix at the base of the nail.

Eponychium

The cuticle that overlaps the proximal end of the nail.

Hyponychium

The skin underneath the free edge of the nail.

Eccrine sweat glands

Sweat glands that are widely distributed across the body, mainly for temperature regulation.

Apocrine sweat glands

Sweat glands found in specific areas (such as armpits), functional at puberty.

Ceruminous glands

Modified sweat glands in the ear canal that produce earwax.

Mammary glands

Modified sweat glands that produce milk.

Acne

A skin condition caused by the blockage and inflammation of sebaceous glands.

Skin markings

Patterns formed by epidermal ridges; enhance grip and contribute to fingerprints.

Wrinkles

Aged skin appearance due to loss of collagen, elastic fibers, and hydration.

Homeostasis

The body's ability to maintain a stable internal environment.

Histology

The study of normal structures of tissues.

Extracellular Matrix (ECM)

Ground Substance & Protein Fibers. The material surrounding cells in a tissue composed of substances in liquid, gel, or solid forms. provide strength to resist stretching and compression and holds cells in place.

Epithelial Tissue

A type of tissue that consists of tightly packed cells that cover and line body surfaces and cavities. provides protection immune defenses, secretion of hormones and oils , transport and sensation. Avascular Tissue and fairly impermeable.

Glandular Epithelia

Epithelia specialized for secretion, including endocrine and exocrine glands.

Endocrine Glands

Glands that secrete hormones directly into the bloodstream without ducts. ex: thyroid, pituitary, ovary

Exocrine Glands

Glands that have ducts and secrete substances with local effects. ex: sweat and salivary glands

Goblet Cells

unicellular and secrete mucus for digestive and respiratory tracts. protects underlying epithelia

Merocrine Secretion 

A type of exocrine secretion where products are released via exocytosis without loss of cell integrity, such as in sweat and salivary glands.

holocrine secretion

A type of exocrine secretion where entire cells disintegrate to release their substance, such as in sebaceous glands.

Skeletal Muscle Tissue

A type of muscle tissue that is striated and under voluntary control.

Cardiac Muscle Tissue

A type of muscle tissue that is striated and involuntary, found in the heart.

Smooth Muscle Tissue

A non-striated, involuntary muscle tissue found in the walls of hollow organs.

Neurons

Cells in nervous tissue capable of transmitting nerve impulses. They consist of a cell body, dendrites, and an axon. They send and receive messages.

Neuroglial Cells

Support cells in nervous tissue that do not conduct impulses.

Regeneration

The process of replacing damaged or dead cells with the same type of cells.

Fibrosis

The process of scar tissue formation, where fibroblasts produce collagen to repair tissue. results in scar tissue 

Simple Squamous Epithelium

A single layer of flat cells that facilitates diffusion, found in air sacs of lungs and line blood vessels. good for rapid diffusion

Stratified Squamous Epithelium

Multiple layers of cells that protect underlying tissues from abrasion, found in skin, mouth, and throat.

Simple Cuboidal Epithelium 

A single layer of cube-shaped cells that functions in secretion and absorption, commonly found in glands and kidney tubules.

Stratified Cuboidal Epithelium

rare in humans. lines ducts of sweat glandsand mammary glands, providing protection and some secretion.

Simple Columnar Epithelium 

A single layer of column-shaped cells that aids in absorption and secretion, typically found in the digestive tract and uterus. often has microvili to increase surface area for absorption.

Stratified Columnar Epithelium 

multiple layers of column-shaped cells that are rare in humans found in male urethra, cornea, and ducts of salivary glands 

Transitional Epithelium (stratified weird)

A type of epithelium consisting of multiple layers of cells that can stretch, found primarily in the urinary bladder, ureters, and part of the urethra, allowing for flexibility and expansion. basal cell layers are cuboidal and the upper layers are flattened or dome-shaped.

Pseudostratified ciliated columnar epithelium

A type of epithelial tissue that appears to have multiple layers due to varying cell heights but is actually a single layer of cells, often found lining the respiratory tract and containing cilia to help move mucus. Found in Trachea and respriratory passages, it helps trap and move particles out of the airways.

Ground Substance

makes up most of extracellular matrix ECM . Made up of extracellular fluid aka interstital fluid, proteoglycans, GAGs, CAMs, and protien fibers.

Glycosaminoglycans (GAGs)

polysaccharides in ECM. ex: chondroitin sulfate (cartilage) and hyaluronic acid

Proteogycans 

macromolecules in the extracellular matrix, consisting of a protein core with glycosaminoglycan side chains. They play a crucial role in regulating the movement of water and nutrients within tissues.

Cell-Adhesion Molecules (CAMs)

Made up of different glycoproteins that bind surface protein and maintain architecture of tissues

Collagen Fibers

Protein fiber that is resistant to tension and pressure. 20-25% of all proteins in the body. (white, fibrous)

Elastic Fibers

protein fibers that provide elasticity and resilience to tissues, allowing them to withstand stretching. (yellow)

Reticular Fibers 

thin, web-like protein fibers that provide a supportive framework for soft tissues and organs. meshwork

carcinogens

substances that are known to cause cancer by altering cellular metabolism or damaging DNA.

carcinoma

a type of cancer that originates in epithelial tissues, such as skin or lining of organs.

basal cell carcinoma

a common type of skin cancer that arises from basal cells in the epidermis. It typically manifests as a growth on sun-exposed areas. basement membrane slows the spread of cancerous cells, making it less aggressive than other skin cancers.

Connective Tissue (CT)

A type of tissue that connects tissues to one another, consists of scattered cells in an ECM, and provides support, protect and transport substances. very vascular

loose connective tissue areolar

a type of connective tissue characterized by a loose arrangement of fibers and cells in the extracellular matrix, providing flexibility and support.

dense regular connective tissue

A type of connective tissue that has tightly packed collagen fibers arranged in parallel, providing strength and resistance to tension in one direction.

dense irregular connective tissue

A type of connective tissue with collagen fibers arranged irregularly, providing strength and support in multiple directions.

reticular connective tissue

A type of connective tissue composed of a network of reticular fibers and cells, providing structural support and a framework for organs such as the liver, spleen, and lymph nodes.

adipose connective tissue

A type of connective tissue that stores fat, providing insulation and cushioning to the body, as well as serving as an energy reserve.

cartilage connective tissue (specialized)

A type of connective tissue that is more flexible than bone, providing support and cushioning to joints, and is found in structures like the nose, ears, and between vertebrae.

bone specialized c.t.

A type of specialized connective tissue that provides structural support and protection to the body, consisting of a hard matrix mineralized with calcium phosphate and collagen fibers.

blood specialized c.t.

A type of specialized connective tissue that circulates throughout the body, consisting of red and white blood cells suspended in plasma, and is crucial for transportation of nutrients, gases, and waste.

hypertrophic obesity

A type of obesity characterized by the enlargement of adipocytes, resulting in an increased fat mass and storage within the body.