Anatomy Mid-Term - Semester 1

Organ

A structure consisting of two or more tissues that perform a specialized function.

Integumentary System

The organ system that includes the skin and its accessory structures.

Epidermis

The outer, epithelial layer of the skin.

Dermis

The thick layer of the skin beneath the epidermis.

Subcutaneous Layer (Hypodermis)

The loose connective tissue layer beneath the skin.

Keratinization

The process by which cells form fibrils of keratin and harden.

Melanin

A dark pigment generally found in skin and hair.

Skin

The largest organ in the body by weight, composed of the epidermis and dermis.

Epithelial Tissue

The type of tissue that makes up the epidermis, a stratified squamous epithelium.

Thick Skin

Stratum basale

Stratum spinosum

Stratum granulosum

Stratum lucidum (only in thick skin)

Stratum corneum

Thin Skin

Stratum basale

Stratum spinosum

Stratum granulosum

Stratum corneum

Connective Tissue

The type of tissue that makes up the dermis, providing strength and elasticity.

Stratum Basale

The deepest layer of the epidermis, containing dividing cells.

Stratum Corneum

The outermost layer of the epidermis, composed of dead epidermal cells.

Melanocytes

Cells in the epidermis that produce and transfer melanin to nearby cells.

Papillary Layer

The uneven boundary between the epidermis and dermis, containing dermal papillae and sensory receptors.

Reticular Layer

Layer in the dermis (roughly 80%) that is composed of dense irregular connective tissue. It contains blood vessels, lymphatic vessels, and nerve fibers, providing support and nourishment to the skin.

Skin Pigmentation

The color of the skin determined by melanin, carotene, and hemoglobin.

Melanin

A pigment responsible for determining skin, hair, and eye color. It also plays a role in protecting the skin from harmful UV radiation.

Carotene

A pigment found in plants that gives fruits and vegetables their vibrant colors. It is converted into vitamin A in the body, which is essential for healthy vision, immune function, and skin health.

Hemoglobin

Protein in red blood cells that carries oxygen from the lungs to body tissues and transports carbon dioxide from tissues back to the lungs.

Clinical – Homeostatic Imbalance

Alterations in skin colour can indicate disease

Cyanosis

Bluish discoloration of the skin and mucous membranes due to insufficient oxygen in the blood.

Erythema

Inflammation of the skin characterized by redness, caused by dilation of blood vessels.

Pallor

Abnormal paleness of the skin, often caused by a decrease in blood flow or low levels of hemoglobin. It can be a symptom of various medical conditions, such as anemia, shock, or cardiovascular diseases.

Jaundice

A yellow discoloration of the skin and eyes due to high levels of bilirubin in the blood. It can be caused by liver disease, blocked bile ducts, or excessive breakdown of red blood cells. Symptoms include yellowing of the skin, dark urine, pale stools, fatigue, and abdominal pain.

bruises

Injury discoloration caused by broken blood vessels beneath the skin. Commonly appears as purple, blue, or black marks. Can be painful and tender to touch. May occur due to trauma, such as bumping into objects or getting hit. Usually fades over time as the body absorbs the blood.

Brown or black "necklace"

A visible dark discoloration that appears around the neck, commonly seen in individuals with insulin resistance or obesity. It is a sign of a medical condition called acanthosis nigricans, characterized by thickened, velvety skin. Can be a risk factor for diabetes and other metabolic disorders.

Nails

Protective plates at the distal end of fingers or toes.

Hair Follicle

A tubelike depression in the skin where a hair develops.

Sebaceous Gland

A skin gland that secretes sebum.

Sweat Gland

An exocrine gland in the skin that secretes a mixture of water, salt, and wastes.

Eccrine (merocrine) sweat glands

Produce sweat that is primarily composed of water, electrolytes, and small amounts of waste products. Found all over the body, especially in the palms, soles of the feet, and forehead. Help regulate body temperature and excrete toxins.

Apocrine sweat glands

Type of sweat glands found in the armpits, groin, and areola. They release a thicker, odorless secretion that bacteria break down, causing body odor.

Ceruminous glands

Glands found in the ear canal that produce cerumen, a waxy substance.

Mammary glands

Mammary glands produce milk in female mammals for nourishing their offspring.

White hair in an individual with albinism

Hair color in individuals with albinism is white due to the absence of melanin pigment.

Body temperature regulation.

The process by which the body maintains a stable internal temperature, typically around 98.6°F (37°C). It involves the hypothalamus, which acts as the body's thermostat. When the body gets too hot, blood vessels dilate, allowing heat to escape through the skin. Sweating also helps cool the body. When the body gets too cold, blood vessels constrict, reducing heat loss. Shivering generates heat.

Hyperthermia

Abnormal increase in body temperature, often caused by prolonged exposure to high temperatures or strenuous physical activity. Can lead to symptoms like dizziness, fatigue, and dehydration. Can be life-threatening if not treated promptly.

Hypothermia

Condition where the body loses heat faster than it can produce, resulting in dangerously low body temperature. Symptoms include shivering, confusion, drowsiness, and weak pulse. Can lead to frostbite, organ failure, and death if not treated promptly. Treat by warming the person slowly, providing warm fluids, and seeking medical help.

Basal cell carcinoma

Most common type of skin cancer.

Typically appears as a pearly, flesh-colored bump or a pinkish patch of skin. Slow-growing and rarely spreads to other parts of the body. Caused by long-term exposure to UV rays from the sun or tanning beds. Can be treated with surgery, radiation therapy, or topical medications.

Squamous cell carcinoma

A type of skin cancer in the outermost layer of the skin. It often appears as a scaly, red patch or a firm, raised bump. It can occur on any part of the body, but is most commonly found on sun-exposed areas like the face, neck, and hands. It has the potential to spread to other parts of the body if left untreated.

Melanoma

Deadliest form of skin cancer. Arises from melanocytes, pigment-producing cells. Often caused by UV exposure. Can spread to other parts of the body. Early detection crucial for successful treatment.

Gray hair

Result of decreased melanin production in hair follicles, causing a loss of pigmentation.

Glands

Specialized cells or organs that produce and secrete substances for specific functions in the body.

Sebaceous glands

Sebaceous glands are associated with hair follicles and secrete sebum, an oily substance that helps keep the skin and hair soft and waterproof.

Sweat gland

Sweat glands are coiled tubes that produce sweat, which helps regulate body temperature and excrete wastes.

Merocrine sweat glands

Merocrine sweat glands respond to elevated body temperature and produce primarily water-based sweat.

Apocrine sweat glands

Apocrine sweat glands respond to emotional upset and produce sweat containing proteins and lipids.

Sebum

An oily secretion produced by sebaceous glands that helps soften hair and skin and has bactericidal properties.

Acne

A skin condition characterized by the overproduction of sebum and the blockage of hair follicles, leading to the formation of pimples.

Sebaceous Glands

Glands in the skin that produce sebum, an oily substance. Helps moisturize the skin and hair. Can become overactive, causing acne.

sudoriferous glands

Glands in the skin that produce sweat.

Sudoriferous glands

Also known as sweat glands, are responsible for producing sweat.

Ceruminous glands

Ceruminous glands are located in the lining of the external ear canal and secrete cerumen (earwax).

Mammary glands

Mammary glands secrete milk for breastfeeding.

Protection

The skin acts as a physical and chemical barrier, protecting the body from external threats such as microorganisms and chemicals.

Body temperature regulation

The skin helps regulate body temperature through processes like sweating and vasodilation or vasoconstriction of blood vessels.

Cutaneous sensations

The skin contains sensory receptors that detect sensations such as touch, pressure, temperature, and pain.

Metabolic functions

The skin plays a role in the production of vitamin D precursor and excretion of wastes like ammonia, urea, and uric acid.

Skin cancer

Skin cancer is the abnormal growth of skin cells, often caused by overexposure to UV radiation.

Hair papilla

It contains a knot of capillaries that supplies nutrients to growing hair

Hair bulb

Expanded area at the deep end of the follicle

Hair matrix

Actively dividing area of bulb that produces hair cells

Arrector pili

A small band of smooth muscle attached to the follic

Hair follicle receptor (or root hair plexus)

Sensory nerve endings that wrap around the bulb

Burns

Tissue damage caused by heat, electricity, radiation, or chemicals, leading to denaturation of proteins and destruction of cells.

Basal cell carcinoma

Most common and least malignant type of skin cancer that slowly invades the dermis and hypodermis.

Squamous cell carcinoma

The second most common type of skin cancer that can metastasize and involves keratinocytes of the stratum spinosum.

Melanoma

Melanoma is the most dangerous type of skin cancer, originating from melanocytes, and is highly metastatic and resistant to chemotherapy.

ABCD rule

A method used to identify potential signs of skin cancer.

A stands for asymmetry, meaning one half of the mole looks different from the other.

B stands for border irregularity, where the edges are not smooth.

C stands for color variation, with different shades present.

D stands for diameter, where moles larger than 6mm may be concerning.

Remember E for evolving, as any changes in size, shape, or color should be monitored."

First-degree burn

First-degree burns only damage the epidermis, causing localized redness, edema, and pain.

Second-degree burn

Second-degree burns damage the epidermis and upper dermis, resulting in blisters.

Third-degree burn

Third-degree burns involve the entire thickness of the skin and may appear gray-white, cherry red, or blackened, with no edema or pain.

Nail bed

A thin layer of skin underneath the nail plate, produced by continuous epithelial cells and nourished by blood vessels.

Hair formation

Hair forms from stem cells in the hair follicle, with older cells pushed outward as the hair grows, nourished by the hair papilla.

Sebaceous gland function

Sebaceous glands produce sebum, which helps keep the skin and hair soft, waterproof, and pliable.

Merocrine sweat gland

Merocrine sweat glands produce watery sweat in response to increased body temperature or emotional stress, opening onto the skin surface.

Apocrine sweat gland

Apocrine sweat glands produce sweat containing proteins and lipids in response to emotional upset, fear, pain, or sexual arousal, opening into hair follicles.

Skin functions

The skin acts as a protective barrier, produces vitamin D precursor, helps regulate body temperature, detects sensory stimuli, and plays a role in wound healing.

Heat loss

Excess heat is lost through vasodilation of dermal blood vessels and evaporation of sweat from the skin's surface.

Heat conservation

Heat is conserved through vasoconstriction of dermal blood vessels and inactivation of sweat glands.

Tissue response to inflammation

Inflammation is characterized by redness, swelling, increased blood flow, and increased metabolic activities to heal the affected area.

Epidermal wound healing

Shallow cuts in the epidermis are filled in by reproducing epithelial cells.

Dermal wound healing

Deeper cuts in the dermis involve blood clotting, fibroblast production of collagen fibers, blood vessel invasion, and phagocyte removal of dead cells.

Phagocytic cells in wound healing

Phagocytic cells engulf and destroy pathogens, remove dead cells and debris from the wound, aiding in the healing process.

Granulation

Granulation refers to the formation of new blood vessels and fibroblasts in large wounds, contributing to the healing process and scar formation.

Skin aging

Characterized by a decrease in epidermal replacement, decreased oil secretion, decreased elasticity, decreased melanocytes, and decreased subcutaneous fat.

Granulation

The process of forming small particles or granules by agglomerating or binding together fine powders or particles.

Functions of the skin

The skin acts as a protective barrier, produces melanin, contains sensory receptors, helps produce vitamin D, regulates body temperature, and aids in wound healing.

Tissue Repair

Process by which damaged or injured tissues are healed and restored to their normal structure and function. It involves inflammation, formation of new blood vessels, proliferation of cells, and remodeling of the tissue.

Connective Tissue

A basic tissue type that consists of cells within an extracellular matrix, including bone, cartilage, blood, and loose and dense connective tissues.

Nervous Tissue

Internal Communication

Brain

Spinal Cord

Nerves

Muscle Tissue

Contracts to cause movement

Muscles attached to bones (skeletal)

Muscles of heart (cardiac)

Muscles of walls of hollow organs (smooth)

Epithelial tissue

Forms boundaries between different environments, protects, secretes, absorbs, filters

Lining of digestive tract organs and other hollow organs

Skin surface (epidermis)

Connective tissue

Supports, protects, binds other tissues together

Bones

Tendons

Fat and other soft padding tissue

Tissues

An assembled group of similar cells that performs a specialized function.

Epithelial

Connective

Muscle

Nervous

The four major types of human tissues