Anatomy - Body Regions and Movements

Body Regions

• Five principal body regions: head, neck, thorax (chest) & abdomen, upper limb (arm), and lower limb (leg).

Movement Terms

• Flexion/Extension: Bending/straightening a joint.
• Abduction/Adduction: Movement away from/towards the midline of the body.
• Rotation/Circumduction: Rotation around an axis/circular movement.
• Pronation/Supination: Rotating forearm so palm faces down/up.
• Inversion/Eversion: Turning sole of foot inward/outward.

Directional Terms

• Anterior/Posterior (Ventral/Dorsal): Front/back of the body; front/back side of organ.
• Superior/Inferior: Above/below.
• Medial/Lateral: Towards the middle/away from the middle of the body.
• Proximal/Distal: Closer to/farther from the point of attachment or origin.
• Superficial/Deep: Closer to/farther from the surface of the body.
• Visceral/Parietal: Internal organs/outer layer.
• Ipsilateral/Contralateral: Same/opposite side of the body.
• Supine/Prone: Lying flat on back/lying flat on stomach.

Epithelial Tissue Types

• Simple Squamous: One layer of flat cells; lining of blood vessels, alveoli. Function: diffusion, filtration, and protection.
• Stratified Squamous: Multiple layers of cells; outer layer flat; skin (keratinized), mouth, esophagus (non-keratinized). Function: protection from abrasion.
• Simple Cuboidal: One layer of cube-shaped cells; kidney tubules, glands, ovary surfaces. Function: secretion and absorption.
• Stratified Cuboidal: Multiple layers of cube-shaped cells; sweat gland ducts, salivary ducts. Function: secretion, absorption, and protection.
• Simple Columnar: One layer of elongated cells; digestive organs, uterine tubes. Function: secretion and absorption.
• Stratified Columnar: Multiple layers of elongated cells; male urethra, pharynx. Function: protection and secretion.
• Pseudostratified Columnar: Appears layered but is single layer; respiratory tract. Function: secretion and movement of mucus via cilia.
• Transitional: Layers change shape depending on tension; urinary bladder, ureters. Function: allows stretching.

Connective Tissues

• Tendon: Connects muscle to bone, composed of dense regular connective tissue; strong, tensile strength.
• Ligament: Connects bone to bone, composed of dense regular connective tissue with elastic fibers. Offers flexibility and stability.

Muscle Tissues

• Skeletal Muscle: Long, cylindrical, striated fibers, multiple nuclei; attached to skeleton; voluntary control; body movement.
• Smooth Muscle: Spindle-shaped, non-striated, single nucleus; walls of hollow organs; involuntary control; moves substances through organs.
• Cardiac Muscle: Branched, striated fibers, single nucleus, intercalated discs; heart; involuntary control; pumps blood.

Extracellular Junctions

• Gap Junctions: Plasma membrane channels allowing substance exchange; communication between cells; cardiac and smooth muscle.
• Adhesion Junctions: Adjacent plasma membranes held by filaments; flexibility; skin.

Skin Function

• Protection: Shields against trauma, UV radiation, pathogens.
• Regulation: Controls water loss, body temperature.
• Sensory Input: Gathers information on touch, pressure, temperature, pain.
• Excretion: Removes waste via sweat.
• Vitamin D Synthesis: Produces vitamin D under UV light.

Epidermis Layers

• Stratum Basale: Single row of actively dividing cells, producing keratin, melanin, Langerhans/Merkel cells.
• Stratum Spinosum: Spiny appearance due to keratin fibers.
• Stratum Granulosum: Flattened cells with keratohyalin granules.
• Stratum Lucidum (thick skin only): Transparent layer offering protection from friction.
• Stratum Corneum: Outermost layer; dead keratinized cells; prevents water loss and blocks pathogens.

Burn Degrees

• First Degree: Epidermis only; redness, pain, no blistering.
• Second Degree: Epidermis and part of dermis; blistering, severe pain.
• Third Degree: Entire skin layer; leathery appearance.
• Fourth Degree: Extends into tissues like muscles and bones.

Skin Color and High Altitude

• High-altitude exposure results in thinner atmosphere and potentially increased UV exposure. Increased melanin protects against UV damage and reduces skin cancer risk.

Albinism

• Genetic disorder causing defective melanin production; pale skin, light hair, increased sensitivity to sunlight, high susceptibility to burns and skin cancer.

Athlete's Foot

• Fungal infection; affects toes and soles; symptoms include itching, scaling, and redness.

Skin Cancer: Melanoma

• Malignant cancer from melanocytes; unusual moles/dark spots; high risk in fair-skinned individuals or those with severe sunburn history. Can metastasize rapidly and requires early detection for effective treatment.

Bone Cells

• Osteoblasts: Produce bone matrix, facilitate bone growth; found on bone surface.
• Osteocytes: Maintain bone tissue; derived from osteoblasts; embedded in bone matrix.
• Osteoclasts: Break down bone tissue for remodeling and calcium release; found on bone surfaces.

Appendicular Skeleton Examples

• Upper Limbs: Humerus, radius, ulna, carpals, metacarpals, phalanges.
• Lower Limbs: Femur, tibia, fibula, tarsals, metatarsals, phalanges .
• Girdles: Pectoral girdle (clavicle and scapula), pelvic girdle (ilium, ischium, pubis).

Vertebrae Regions

• Cervical: 7 vertebrae; supports head, allows for neck movement.
• Thoracic: 12 vertebrae; articulates with ribs.
• Lumbar: 5 vertebrae; bears most weight, provides flexibility, movement.
• Sacral: 5 fused vertebrae; forms sacrum, connects spine to pelvis.
• Coccygeal: 3-5 fused vertebrae; forms coccyx (tailbone).

Gout

• Type of arthritis caused by uric acid crystal accumulation in joints, commonly in the big toe, knees, and ankles. Severe pain, redness, swelling, and heat in affected joints; high levels of uric acid in the blood due to diet, genetics, or kidney dysfunction. Management involves anti-inflammatory medications, dietary changes (avoiding purine-rich foods), and maintaining hydration.