Anatomy & Physiology: Foundational Concepts and Systems Overview

Anatomy and Physiology: Introduction

Definitions and Scope

• Anatomy: The study of the structure of the human body.

• Physiology: The study of body function.

• Relationship: Anatomy affects function (e.g., a broken bone disrupts function), and physiology explains how anatomy works.

Subdisciplines of Anatomy

Gross Anatomy

• Study of structures visible to the naked eye.

• Regional anatomy: Examines specific areas (e.g., upper limb, lower limb).

• Systemic anatomy: Studies organ systems (e.g., digestive, nervous).

Surface Anatomy

• Study of external features and their relation to deeper structures.

Microscopic Anatomy (Histology)

• Study of structures requiring magnification, such as cells and tissues.

Other Branches

• Developmental anatomy: Study from conception to maturity.

• Embryology: Study of development before birth.

• Pathological anatomy: Study of structural changes due to disease.

• Radiographic anatomy: Study using imaging techniques.

• Functional morphology: Study of structure-function relationships.

The Hierarchy of Structural Organization

• Chemical level: Atoms combine to form molecules (e.g., Na + Cl → NaCl).

• Cellular level: Cells are the smallest living units; cancer disrupts this level.

• Tissue level: Groups of similar cells form tissues (epithelial, connective, muscle, nervous).

• Organ level: Different tissues combine to form organs (e.g., heart, stomach).

• Organ system level: Organs work together in systems (e.g., cardiovascular, muscular).

• Organism level: All systems function together to sustain life.

Overview of Body Systems

Integumentary System

• Composed of skin, hair, nails.

• Protects deeper tissues, synthesizes vitamin D, contains sensory receptors and glands.

Skeletal System

• Protects and supports organs, provides framework for muscles, forms blood cells, stores minerals (e.g., calcium, phosphorus).

Muscular System

• Allows movement, maintains posture, produces heat.

• Types: Skeletal, cardiac, smooth muscle.

Nervous System

• Fast-acting control system; regulates muscles and glands.

Endocrine System

• Glands secrete hormones regulating growth, reproduction, metabolism.

Cardiovascular System

• Heart and blood vessels transport blood, oxygen, nutrients, wastes.

Lymphatic System/Immunity

• Returns leaked fluid to blood, disposes of debris, houses lymphocytes, mounts immune response.

Respiratory System

• Keeps blood supplied with oxygen, removes carbon dioxide.

Digestive System

• Breaks down food, absorbs nutrients, eliminates waste.

Urinary System

• Eliminates nitrogenous wastes, regulates water, electrolytes, acid-base balance.

Units of Measurement

• Weight: Kilogram (kg), gram (g)

• Height: Centimeter (cm), micrometer (μm)

Gross Anatomy: An Introduction

Anatomical Position and Terms

• Standard position: Standing upright, palms forward.

• Anterior: Front; Posterior: Back.

• Axial region: Head, neck, trunk.

• Appendicular region: Limbs.

Body Regions and Landmarks

• Cephalic (head): Frontal (forehead), orbital (eyes), nasal (nose), oral (mouth), mental (chin).

• Cervical: Neck.

• Thoracic: Sternal (mid-chest), axillary (armpit), mammary (breast).

• Abdominal: Umbilical (navel).

• Pelvic: Inguinal (groin), pubic (genital).

• Upper limb: Acromial (shoulder), brachial (arm), antebrachial (forearm), carpal (wrist).

• Manus (hand): Pollex (thumb), palmar (palm), digital (fingers).

• Lower limb: Coxal (hip), femoral (thigh), patellar (knee), crural (leg), fibular (side of leg).

• Pedal (foot): Tarsal (ankle), calcaneal (heel), metatarsal (foot bones), digital (toes), hallux (big toe).

Directional Terms

• Superior: Toward the head.

• Inferior: Away from the head.

• Proximal: Closer to the point of attachment.

• Distal: Farther from the point of attachment.

• Medial: Toward the midline.

• Lateral: Away from the midline.

• Superficial: Toward the surface.

• Deep: Away from the surface.

Planes of the Body

• Median (midsagittal) plane: Divides body into left and right halves.

• Frontal (coronal) plane: Divides body into anterior and posterior parts.

• Transverse plane: Divides body into superior and inferior parts.

Body Cavities

• Vertebral cavity: Contains the spinal cord.

• Abdominal cavity: Contains digestive organs.

• Pelvic cavity: Contains bladder, reproductive organs.

• Cranial cavity: Contains the brain.

Serous Cavities

• Serous membranes line body cavities and cover organs.

• Pleura: Lungs; Pericardium: Heart; Peritoneum: Abdominal organs.

Abdominal Quadrants

• Right upper quadrant: Liver, gallbladder.

• Left upper quadrant: Stomach.

• Right lower quadrant: Appendix.

• Left lower quadrant: Large and small intestine.

Clinical Anatomy: Medical Imaging Techniques

• X-ray: Best for bones and dense structures.

• Computed tomography (CT): Cross-sectional images of body.

• Angiography: Visualizes blood vessels using contrast medium.

• Positron emission tomography (PET): Detects radioactive isotopes in tissues.

• Sonography (ultrasound): Uses high-frequency sound waves for imaging soft tissues.

• Magnetic resonance imaging (MRI): High-contrast images of soft tissues, based on water content.

Cells: The Living Units

Overview of Cells

• Cells are the smallest living units.

• All living things are made of cells.

• Cells perform essential functions: metabolism, waste disposal, shape maintenance, replication (via mitosis).

Cell Structure

• Plasma membrane: Outer boundary, controls entry/exit.

• Cytoplasm: Contains organelles.

• Nucleus: Controls cellular activity.

Plasma Membrane Structure

• Fluid mosaic model: Lipid bilayer with proteins and cholesterol.

• Proteins act as channels, receptors, and enzymes.

• Cholesterol modulates fluidity and stability.

• Carbohydrates attach to proteins/lipids (glycoproteins, glycolipids) for cell recognition.

Organelles

• Specialized subunits with specific functions (e.g., mitochondria, ribosomes).

The Skeleton

Overview

• Consists of bones, cartilage, joints, ligaments.

• Joints are called articulations.

• Yellow bone in slides is appendicular; green is axial.

• Cranial and facial bones make up the skull.

The Skull

• Protects the brain; most complex bony structure.

• Formed by cranial and facial bones.

• Facial bones form framework for face, cavities for sense organs, openings for air/food, anchor facial muscles.

• Sutures are immovable joints between skull bones.

Skull Geography

• Facial bones from anterior aspect; cranium divided into cranial vault and base.

• Major cranial fossae: anterior, middle, posterior.

• Smaller cavities: middle/inner ear, nasal cavity, orbits, paranasal sinuses.

• Temporal bone: houses mastoid process, external acoustic meatus, zygomatic process.

• Mandible: lower jaw, contains teeth.

Summary Table: Body Tissue Types

Tissue Type	Main Function	Example
Epithelial	Covering/lining surfaces	Skin, lining of GI tract
Connective	Support, protection, binding	Bone, blood, fat
Muscle	Movement	Skeletal muscle, heart
Nervous	Control, communication	Brain, nerves

Additional info:

• Some anatomical terms and regions were inferred based on standard anatomical nomenclature.

• Some details about the function of cholesterol and types of lipids in the plasma membrane were expanded for clarity.

• Clinical imaging techniques were described with typical uses and principles.