Anatomy and Physiology Basics

Anatomy and Physiology

• Anatomy studies body parts' structure and organization.
• Physiology studies how body parts function.
• Anatomy focuses on structure, physiology on function.

Standard Anatomical Position (SAP)

• The body is upright, facing forward with feet together.
• The arms are at the sides, with palms facing forward and thumbs pointing outward.

Supine and Prone

• Supine position is lying face up.
• Prone position is lying face down.

Body Planes

• Sagittal Plane divides the body into left and right portions.
• Frontal (Coronal) Plane divides the body into anterior (front) and posterior (back) sections.
• Transverse Plane divides the body into superior (upper) and inferior (lower) parts.

Directional Terms

• Superior means above, inferior means below; the head is superior to the chest.
• Anterior means front, posterior means back; the sternum is anterior to the heart.
• Medial means closer to midline, lateral means farther from midline; the nose is medial to the eyes.
• Proximal means closer to limb attachment, distal means farther from limb attachment; the elbow is proximal to the wrist.
• Superficial means closer to the surface, deep means farther from the surface; the skin is superficial to muscles.

Body Regions

• The Axial Region includes the head, neck, and trunk.
• The Appendicular Region includes limbs and appendages.

Subregions

• Cephalic refers to the head.
• Cervical refers to the neck.
• Brachial refers to the arm.
• Antebrachial refers to the forearm.
• Axillary refers to the armpit.
• Palmar refers to the anterior surface of the hand.

Body Cavities

• The Cranial Cavity contains the brain.
• The Vertebral (Spinal) Cavity contains the spinal cord.
• The Thoracic Cavity contains the heart and lungs.
• The Abdominopelvic Cavity contains digestive, urinary, and reproductive organs, and is divided into abdominal and pelvic cavities.

Cell Characteristics

• Cells have internal components separated from the external environment via the plasma membrane, organelles and cytoplasm.
• Cells exchange materials and communicate.
• Cells contain DNA, which is the genetic material.
• Cells coordinate and regulate activities to perform specific functions.

Plasma Membrane

• The Plasma Membrane is a Phospholipid bilayer with embedded proteins.
• The Plasma Membrane is a semipermeable barrier, determines what enters/exits the cell, allows cell-to-cell communication, provides structural support and maintains cellular shape.

Organelles

• Nucleus: Located in the center of the cell, controls cell activities and stores DNA; structure - Nuclear membrane with pores
• Ribosomes: Located free-floating or on Rough ER, Protein synthesis; structure - Small subunits made of rRNA & proteins
• Rough ER: Located near the nucleus, Modifies/transports proteins; structure - Membrane network with ribosomes attached
• Smooth ER: Located throughout the cytoplasm, Lipid synthesis, detoxification; structure - Membrane network, no ribosomes
• Golgi Apparatus: Located near Rough ER, Modifies, packages, and ships proteins; structure - Stacked, flattened membrane sacs
• Mitochondria: Located throughout the cytoplasm, Produces ATP (cell energy), structure - Double membrane, inner folds (cristae).
• Cytoskeleton: Located throughout the cytoplasm, Supports shape and aids in movement structure - Network of microfilaments & microtubules.
• Plasma Membrane: Located surrounding the cell, Regulates what enters & exits the cell; structure - Phospholipid bilayer with embedded proteins
• Cytoplasm: Located inside the cell, Supports organelles, site of chemical reactions; structure - Gel-like fluid (cytosol) and organelles
• Cytosol: Located Throughout cytoplasm, Fluid that suspends organelles, site of metabolism; structure - Gel-like, mostly water with dissolved substances

Cytoskeleton Protein Filaments

• Microfilaments: Located throughout the cytoplasm, especially beneath the plasma membrane; provides cell shape, aids in movement and supports cell division (cytokinesis); structure - thin, solid rods made of actin protein
• Microtubules: Located extending from the centrosome throughout the cytoplasm; maintains cell shape and acts as tracks for organelle movement, forms spindle fibers in mitosis; structure - hollow tubes made of tubulin protein

Cilia and Flagella

• Cilia: Located on the cell surface and moves substances across the cell surface. Description - Short, hair-like projections.
• Flagella: Locatedd on the cell surface and it enables cell movement. Description - Long, whip-like tail, such as a sperm cell.

Lysosomes and Peroxisomes

• Lysosomes location is in cytoplasm. The cell's waste and cellular debris; it breaks down cellular waste and debris.
• Peroxisomes location is in cytoplasm. They breaks down fatty acids & detoxifies substances; it breaks down fatty acids and detoxifies harmful substances.

Tissues

• Tissues are groups of similar cells performing a specific function.
• The four general types of tissues are Epithelial, Connective, Muscle, and Nervous.

Epithelial Tissue Characteristics

• Epithelial tissue cells are closely joined together.
• Epithelial tissue has little to no extracellular matrix.
• Epithelial tissue can be innervated and avascular (lack blood supply).
• Epithelial tissue is anchored to a basement membrane, and it easily regenerates.

Epithelial Tissue Location

• Epithelial tissues line all body surfaces and cavities.
• They form internal and external organ linings and comprise most glands.

Epithelial Tissue Functions

• Epithelial tissues provide physical protection.
• Epithelial tissues facilitate movement of materials (diffusion/filtration).
• Epithelial tissues produce secretions.
• Epithelial tissues provide sensory information to the nervous system.
• Epithelial tissues facilitates absorption.

Categorization of Epithelial Tissues

• Epithelial Tissues are categorized by shape and layers.

Types and Functions of Epithelial Tissues

• Simple Squamous is found in blood vessels, alveoli of lungs, and serous membranes, with functions of diffusion, filtration, and absorption.
• Stratified Squamous is found in skin, mouth, esophagus, vagina, anus, and its function is protection against abrasion and water loss.
• Simple Columnar is found in stomach, intestines, and GI tract, with functions of absorption, secretion, mucus movement, and protection against harmful substances.
• Simple Cuboidal is found in kidney tubules, ducts of glands, thyroid gland, and ovary surface, with function of secretion and absorption.
• Transitional is found in urinary bladder and ureters, with the function is allowing stretching and expansion.

Connective Tissue Functions

• Connective tissues provide structural support, cushioning, and protection.
• Connective tissues are used in energy storage and nutrient transport.
• Connective tissues connect/bind structures, and facilitate red blood cell production.

Connective Tissue Components

• Connective tissues contain cells, protein fibers (collagen, elastin, reticular), and ground substance (non-living, fluid-like material).

Connective Tissue Fibers and Ground Substance

• Collagen fibers are long straight fibers that are stretch resistant and provide support, and are common.
• Elastin fibers are branched and thread-like, stretchy and flexible, similar to thin hair.
• Reticular fibers are mesh-work cross-link fibers that provide structural support and house many cells.
• Ground substance is a non-living, fluid-like material that consists of proteins, carbohydrates, and water.
• The matrix is the non-living extracellular material made of ground substance and protein fibers.

Areolar Connective Tissue

• Cell type: Fibroblasts, macrophages, mast cells.
• Extracellular Matrix: Collagen, elastic, reticular fibers, semi liquid gel-like ground substance.
• Function: attaches skin to underlying muscle, surrounds/supports blood vessels, and fill spaces between organs.
• Location: Under epithelia, surrounds organs and blood vessels.

Adipose Connective Tissue

• Cell type: Adipocytes.
• Extracellular Matrix: Little fibers, mostly fat-storing cells.
• Function: Energy storage
• Location: Hypodermis, around kidneys, eyes, abdomen.

Reticular Connective Tissue

• Cell type: Fibroblasts.
• Extracellular Matrix: Mesh like network- reticular fibers, loose ground substance.
• Function: Supports framework for lymphoid structures.
• Location: Lymph nodes, spleen, bone marrow.

Dense Regular Connective Tissue

• Cell type: Fibroblasts.
• Extracellular Matrix: Parallel collagen fibers, viscous ground substance.
• Function: Resists tensile stress in one direction
• Location: Tendons, ligaments, synovial sacs.

Dense Irregular Connective Tissue

• Cell type: Fibroblasts
• Extracellular Matrix: thick wavy collagen fibers, Viscous ground substance
• Function: strength and support
• Location: Dermis of skin, fibrous joint capsules

Hyaline Cartilage

• Cell type: Chondrocytes in lacunae
• Extracellular Matrix: Collagen fibers
• Function: Provides smooth surface, support, flexibility
• Location: Ends of long bones, nose, trachea, rib cartilage

Fibrocartilage

• Cell type: Chondrocytes, fibroblasts
• Extracellular Matrix: Wavy or regularly arranged bundles of collagen fibers
• Function: Absorbs shock, resists compression
• Location: Intervertebral discs, knee menisci, pubic symphysis

Elastic Cartilage

• Cell type: Chondrocytes in lacunae
• Extracellular Matrix: Elastic fibers, flexible ground substance
• Function: Provides flexibility while maintaining shape
• Location: Ear (pinna), epiglottis, auricle of ear

Bone Connective Tissue

• Cell type: Osteocytes in lacunae
• Extracellular Matrix: rings of collagen fibers in hydroxyapatite, calcified ground substance
• Function: strong, shatter resistant, Supports, protects, stores calcium
• Vascular and Innervated
• Location: Bones (skeleton)

Blood Connective Tissue

• Cell type: Red and white blood cells
• Extracellular Matrix: Plasma (fluid ECM) water/protein matrix
• Function: Transports oxygen
• Location: Inside blood vessels

Muscle Tissue

• Muscle tissue is characterized by contractibility and densely packed fibers (cells).

Muscle Tissue Types

• Skeletal muscle is found along the skeleton.
• Cardiac muscle is found in the heart.
• Smooth muscle is found in the walls of hollow organs.

Skeletal Muscle

• Location: Attached to bones.
• Characteristics: Voluntary, striated, multinucleated, long parallel fibers.
• Function: Movement of the body, support.

Cardiac Muscle

• Location: Heart walls
• Characteristics: Involuntary, striated, mononucleated, branched fibers, intercalated discs.
• Function: Pumps blood through the heart and body.

Smooth Muscle

• Location: Walls of hollow organs, surrounding viscera (stomach, intestines, blood vessels, uterus).
• Characteristics: Involuntary, non-striated, mononucleated, spindle-shaped fibers.
• Function: Moves substances through organs (digestion, blood flow, etc.), and provides squeezing action.

Nervous Tissue:

• Nervous tissue conducts electrical impulses/signals, which consists of Neurons and Neuroglia transmit impulses.
• Neurons transmit electrical impulses, while neuroglia support and protect neurons.

Membranes

• The two general types of membranes found in the body are Mucous and Serous membranes.

Mucous Membranes:

• Mucous membranes are different types of epithelial tissue over areolar connective tissue.
• Mucous membranes Line cavities that open to the outside of the body, form a barrier against pathogens, and provide moisture via mucus.

Serous Membranes:

• Serous membranes are thin, double-layered membranes that secrete serous fluid to reduce friction between organs and surrounding structures.
• The parietal layer lines the cavity, and the visceral layer lines the organs.
• The histology includes Mesothelium (simple squamous epithelial) and underlying connective tissue (areolar) .

Serous Membrane Cavities:

• Serous membranes are found in the pleura and pericardium.

Membranes:

• Synovial membranes: Line the cavities of freely moveable joints (e.g., knee).
• Meninges: Line the brain and spinal cord.
• Cutaneous membrane: Skin.

Glands:

• Endocrine - lack ducts and secrete their products into the intercellular fluid or bloodstream.
• Exocrine glands secrete their products via ducts onto the surface of the skin or into internal passageways.

Integumentary System

• The integumentary system includes skin, hair, nails, and glands.

Skin Layers

• The two subdivisions of the skin layers are the epidermis and dermis.

Epidermis

• The epidermis is Keratinized stratified squamous epithelium over cuboidal epithelium.
• The epidermis is avascular and innervated, and of varying thickness, with thick regions having 5 layers and thin regions having 4.

Hypodermis

• The hypodermis is a subcutaneous layer, deepest layer of skin.
• Functions: Connects skin to underlying muscles and bones, site for fat storage.
• Structure: Areolar and adipose connective tissue.

Epidermis Structure

• The epidermis is Stratified squamous epithelium over cuboidal epithelium.

Epidermis Layers

• The five layers of the epidermis are Stratum Corneum, Stratum Lucidum, Stratum Granulosum, Stratum Spinosum, and Stratum Basale.

Epidermis Layers and Cell Types

• Stratum Basale: consists of Keratinocytes, Melanocytes, Merkel cells, and is a single layer of dividing cuboidal cells and the site of melanin production.

• Stratum Spinosum: consists of Keratinocytes and Langerhans cells (dendritic cells) is several layers with spiny projections and is part of the immune defense (Langerhans cells).

• Stratum Granulosum: consists of Keratinocytes that are dying,begin keratin production, and create waterproof barrier.

• Stratum Lucidum: consists of Flattened, dead clear keratinocytes and is only in thick skin (palms, soles), for extra protection.

• Stratum Corneum: consists of Dead keratinocytes (corneocytes) that are flattened, dead, dehydrated cells to create protective barrier; constantly shed.

Dermis Layers

• Papillary: The papillary layer has areolar connective tissue, capillaries, nerve endings, and dermal papillae(fingerprint formation).
• Reticular: The reticular layer has dense irregular connective tissue, hair follicles, sebaceous glands, and sweat glands,.

Skin Layer Function

• Papillary - forms ridges for fingerprint formation
• Reticular - provides strength and elasticity to the skin.

Dermal Papillae

• Dermal papillae are Ridge projections that form fingerprints and increase surface area for exchange between dermis and epidermis.

Nails and Hair

• Nails are a structure that protects fingertips and toes, composed of keratinized plates of flattened epidermal cells.
• Hair protects against UV, cushions, and provides insulation, composed of a keratinized epithelial tube produced by hair follicles

Glands:

• Sweat glands produce sweat for regulating body temperature and excretion of wastes.

Secretions :

• Sebaceous glands produce sebum (oil)
• Sebaceous Glands function : moisturizing and lubricating the skin, and inhibiting bacterial growth.

Skin Functions

• Thermoregulation: Sweat gland excretion regulates body temperature.
• Absorption: Absorbs materials through the skin.
• Hydroregulation: Regulates water, and prevents loss or gain.
• Protection: Protects against UV, bacteria, chemicals, and friction.
  • Chemical Protection: Sebum, keratin, and melanin. -Physical Protection: Stratum corneum and hair.
• Reception: Sensory receptors detect temperature, touch, pressure, and pain.
• Synthesis: Creates Vitamin D, and absorbs calcium, and phosphorus.

Explore the fundamentals of anatomy and physiology. Learn about body structures, their functions, and anatomical positions. Understand body planes and directional terms for accurate anatomical description.