Introduction to Integumentary System

Anatomical Terms

• Gross Anatomy: Refers to structures visible with the unaided eye.
• Lateral: A structure is located on the side of the body.
• Cells: The basic units of life.
• Posterior (Dorsal): Toward the back of the body.
• Proximal: A position closer to the main mass of the body or point of attachment.
• Distal: A position farther from the main mass of the body or point of attachment.
• Superior (Cranial): Toward the head.
• Inferior (Caudal): Toward the tail or feet.
• Medial: Toward the midline of the body.
• Standard Anatomical Position: Body standing erect, feet slightly apart, palms facing forward, and thumbs pointing away from the body.
• Frontal (Coronal) Plane: Divides the body into anterior and posterior portions.
• Transverse (Horizontal) Plane: Divides the body into superior and inferior portions.
• Sagittal Plane: Divides the body into left and right portions.
• Midsagittal Plane: Divides the body into equal left and right halves.
• Dorsal Body Cavity: Encloses the brain and spinal cord.
• Ventral Body Cavity: Houses the internal organs.
• Thoracic Cavity: Contains the heart and lungs, surrounded by the rib cage.
• Abdominopelvic Cavity: Extends from the diaphragm to the pelvis.
• Abdominal Cavity: Upper portion of the abdominopelvic cavity containing the stomach, liver, intestines, etc.
• Pelvic Cavity: Lower portion of the abdominopelvic cavity containing the bladder, reproductive organs, and rectum.
• Pleural Cavities: Two lateral chambers in the thoracic cavity, each containing a lung.
• Pericardial Cavity: Surrounds the heart.

Tissues

Epithelial Tissue

• Epithelium: Covers body surfaces, lines body cavities, and forms glands.
• Simple Epithelium: Consists of a single layer of cells.
• Stratified Epithelium: Consists of multiple layers of cells.
• Squamous Epithelium: Characterized by thin, flattened cells.
• Cuboidal Epithelium: Characterized by cube-shaped cells.
• Columnar Epithelium: Characterized by tall, column-shaped cells.
• Simple Squamous Epithelium: Found in areas where diffusion and filtration occur, such as the lining of blood vessels and alveoli.
• Stratified Squamous Epithelium: Found in areas subject to abrasion, such as the skin and lining of the mouth.
• Simple Cuboidal Epithelium: Found in areas involved in secretion and absorption, such as the lining of kidney tubules and glands.
• Stratified Cuboidal Epithelium: Rare but found in areas such as the lining of ducts.
• Simple Columnar Epithelium: Found in the lining of the stomach and intestines.
• Stratified Columnar Epithelium: Found in areas subject to abrasion, such as the lining of the male urethra.
• Pseudostratified Columnar Epithelium: Appears stratified but is actually a single layer of cells; found in the lining of the respiratory tract.
• Transitional Epithelium: Found in areas that stretch and change shape, such as the urinary bladder.

Connective Tissue

• Connective Tissue: Supports, binds, and protects other tissues.
• Adipose Tissue: Composed primarily of fat cells (adipocytes) and stores energy.
• Fibroblasts: Cells that produce collagen and elastin fibers.
• Dense Connective Tissue: Contains densely packed collagen fibers.

Muscle Tissue

• Skeletal Muscle Tissue: Attached to bones and is responsible for body movement; voluntary control.
• Cardiac Muscle Tissue: Found only in the heart; involuntary control.
• Smooth MuscleTissue: Found in the walls of internal organs and blood vessels; involuntary control.

Skin

• Skin (Integument): The largest organ of the body, composed of two layers.
• Epidermis: Outermost layer of the skin, composed of stratified squamous epithelium.
• Dermis: Underlying layer of the skin, composed of dense connective tissue.
• Hypodermis (Subcutaneous Layer): Deepest layer of the skin, composed of loose connective tissue and adipose tissue.
• Keratinocytes: The most common type of skin cell, produces a tough protein called keratin.
• Melanocytes: Produce melanin, a pigment that gives skin its color and protects it from UV radiation.
• Stratum Basale: Deepest layer of the epidermis, where new skin cells are produced.
• Stratum Spinosum: A layer of the epidermis where cells are linked by desmosomes.
• Stratum Granulosum: A layer of the epidermis where cells undergo keratinization.
• Stratum Lucidum: A layer of the epidermis found only in thick skin, which is present on the palms of hands and soles of feet.
• Stratum Corneum: The outermost layer of the epidermis, composed of dead, keratinized cells.
• Papillary Layer: Outer layer of the dermis, containing dermal papillae that extend into the epidermis.
• Reticular Layer: Deeper layer of the dermis, composed of dense connective tissue.

Respiratory Tract

• Cilia: Hair-like projections that help move mucus and debris.

Functions of Tissues

• Simple Squamous Epithelium: Diffusion and filtration.
• Stratified Squamous Epithelium: Protection against abrasion.
• Simple Cuboidal Epithelium: Secretion and absorption.
• Stratified Cuboidal Epithelium: Secretion and absorption.
• Simple Columnar Epithelium: Secretion and absorption.
• Stratified Columnar Epithelium: Protection.
• Pseudostratified Columnar Epithelium: Secretion and movement of mucus.
• Transitional Epithelium: Stretching and changing shape.
• Adipose Tissue: Energy storage and insulation.
• Dense Connective Tissue: Support and binding.
• Skeletal Muscle Tissue: Voluntary movement.
• Cardiac Muscle Tissue: Heart contraction.
• Smooth Muscle Tissue: Involuntary movement of internal organs.