BIOS251 Exam 3 Weeks

Integumentary System

The system that includes the skin and its appendages, serving functions such as protection, sensation, thermoregulation, and Vitamin D synthesis.

Epidermis

The outermost layer of skin comprised of keratinized stratified squamous epithelium, consisting of five cell types.

Functions of Skin

1. Protection 2. Synthesis of Vitamin D 3. Sensation 4. Thermoregulation 5. Nonverbal communication.

Keratinocytes

The predominant cell type in the epidermis, making up about 90% of all epidermal cells, responsible for producing keratin.

Melanocytes

Cells in the epidermis that produce the pigment melanin, providing protection against UV radiation.

Langerhans cells

Immune cells of the skin that help mount an immune response to pathogens.

Dermis

The thick layer of skin beneath the epidermis, composed of collagen, elastic fibers, blood vessels, and nerve endings.

Papillary Layer

The superficial layer of the dermis made of areolar tissue, rich in blood supply and providing nutrients to the epidermis.

Reticular Layer

The deeper layer of the dermis composed of dense irregular connective tissue containing hair follicles and glands.

Hypodermis (Subcutaneous Layer)

The layer beneath the skin, composed mainly of loose connective tissue, including adipose tissue, providing insulation and energy storage.

Exocrine Glands

Glands such as sweat glands and sebaceous glands that secrete their products through ducts to the skin surface.

Thermoregulation

The process by which the body maintains its internal temperature, achieved by sweating and adjusting blood flow.

First Degree Burns

Burns that affect only the epidermis, causing redness and minor pain, typically healing within days.

Second Degree Burns

Burns that damage the epidermis and part of the dermis, characterized by blistering and possibly scarring.

Third Degree Burns

Full-thickness burns affecting all layers of the skin, which may require skin grafting due to extensive damage.

Basal Cell Carcinoma

The most common type of skin cancer, originating from stratum basale cells; it rarely metastasizes.

Melanoma

A serious type of skin cancer that originates in melanocytes, characterized by irregular borders and rapid metastasis.

Compact Bone

Dense bone tissue that provides strength and support; organized into osteons.

Spongy Bone

Lightweight bone tissue containing trabeculae, found at the ends of long bones and in the interior of others.

Osteoblasts

Bone-forming cells that synthesize new bone matrix.

Osteoclasts

Bone-resorbing cells responsible for the breakdown of bone tissue.

Synovial Joint

A freely movable joint characterized by a synovial cavity, articular cartilage, and reinforced by ligaments.

Synarthrosis

A type of joint that allows no movement.

Amphiarthrosis

A type of joint that allows limited movement.

Diarthrosis

A type of joint that is freely movable.

Flexion

The act of decreasing the angle between two bones at a joint.

Extension

The act of increasing the angle between two bones at a joint.

Circumduction

A circular movement of a limb that outlines a cone-shaped path.

Calcitonin

A hormone that decreases blood calcium levels by reducing osteoclast activity.

Osteoporosis

A condition characterized by a decrease in bone density, making bones fragile and more prone to fractures.

Rickets

A condition in children caused by vitamin D deficiency, leading to softened bones and deformities.

Gouty Arthritis

A form of arthritis caused by the accumulation of uric acid crystals in joints.