Anatomy & Physiology: Foundations, Organization, and Cellular Function

Basic Functions of Living Organisms

Essential Characteristics of Life

• Responsiveness (Irritability): Ability to detect and respond to changes in the environment. Example: Moving hand from hot stove.

• Growth: Increase in size via cell growth and division.

• Differentiation: Cells become specialized for specific functions.

• Reproduction: Production of new generations of organisms.

• Movement: Internal (transport of blood, food, materials) and external (moving through environment).

• Metabolism: All chemical reactions in the body, including energy production and use.

• Excretion: Elimination of waste products.

Relationship Between Anatomy and Physiology

Definitions and Scope

• Anatomy: Study of structure; "cutting open". Types: Gross (macroscopic), Microscopic (cytology, histology).

• Physiology: Study of function; includes cell, organ, systemic, and pathological physiology.

Levels of Organization in Organisms

Hierarchical Structure

• Chemical Level: Atoms combine to form molecules (e.g., DNA).

• Cellular Level: Molecules form organelles, which make up cells.

• Tissue Level: Groups of similar cells perform specific functions (e.g., muscle, nervous tissue).

• Organ Level: Organs are structures made of two or more tissues (e.g., heart, stomach).

• Organ System Level: Organs interact for a common function (e.g., digestive system).

• Organism Level: All organ systems working together.

Organ Systems of the Human Body

Major Systems and Functions

• Integumentary: Protection, temperature regulation, sensory information.

• Skeletal: Support, protection, mineral storage, blood cell formation.

• Muscular: Movement, support, heat production.

• Nervous: Immediate responses, coordination, interpretation of sensory information.

• Endocrine: Long-term changes, metabolism regulation.

• Cardiovascular: Transport of cells and dissolved materials.

• Lymphatic: Defense, returns tissue fluids to bloodstream.

• Respiratory: Gas exchange, sound production.

• Digestive: Processes food, absorbs nutrients, eliminates waste.

• Urinary: Eliminates waste, controls water balance.

• Reproductive: Produces sex cells and hormones.

Body Cavities and Regions

Major Cavities and Subdivisions

• Body Cavities: Fluid-filled spaces lined by serous membranes.

• Thoracic Cavity: Contains pleural cavities (lungs) and pericardial cavity (heart).

• Abdominopelvic Cavity: Contains abdominal (digestive organs) and pelvic (reproductive, urinary) cavities.

Anatomical Terminology

Positions, Directions, and Planes

• Anatomical Position: Standing upright, palms forward.

• Directional Terms:

  • Anterior (ventral): Front of the body.

  • Posterior (dorsal): Back of the body.

  • Superior (cranial): Above another part.

  • Inferior (caudal): Below another part.

  • Medial: Toward the midline.

  • Lateral: Away from the midline.

  • Proximal: Closer to the point of attachment.

  • Distal: Farther from the point of attachment.

  • Superficial: Near the surface.

  • Deep: Farther from the surface.

• Body Planes:

  • Sagittal: Divides body into left and right.

  • Frontal (coronal): Divides body into front and back.

  • Transverse: Divides body into upper and lower portions.

Homeostasis

Concept and Regulation

• Homeostasis: Maintaining stable internal environment.

• Negative Feedback: Opposes change to restore balance. Example: Body temperature regulation.

• Positive Feedback: Amplifies initial stimulus. Example: Blood clotting.

Atoms, Molecules, and Chemical Organization

Atomic Structure and Chemical Bonds

• Atoms: Smallest stable units of matter. Components: Protons, neutrons, electrons.

• Electron Shells: Electrons occupy shells; outer shell determines chemical behavior.

• Molecules: Two or more atoms bonded together.

• Compounds: Molecules with different elements in fixed proportions.

• Chemical Bonds:

  • Ionic: Electrons transferred.

  • Covalent: Electrons shared.

  • Hydrogen: Weak attractions between molecules.

Enzymes and Metabolism

Role of Enzymes

• Enzymes: Biological catalysts that lower activation energy and speed up reactions.

• Reaction Process:

  • Substrate binds to enzyme's active site.

  • Enzyme-substrate complex forms.

  • Product released; enzyme reused.

• Metabolism: Sum of all chemical reactions in the body.

Organic and Inorganic Compounds

Classification and Examples

• Inorganic Compounds: Usually small, lack carbon-hydrogen bonds. Examples: Water, salts, acids, bases.

• Organic Compounds: Contain carbon-hydrogen bonds. Examples: Carbohydrates, lipids, proteins, nucleic acids.

Water and pH in Physiology

Properties and Importance

• Water: Most important substance in the body; solvent, temperature regulation, transport.

• pH Scale: Measures concentration of hydrogen ions ($pH = -\log[H^+]$). Neutral: pH 7; Acidic: pH < 7; Basic: pH > 7.

• Buffers: Compounds that stabilize pH by removing or releasing $H^+$ ions.

Cell Theory and Structure

Fundamental Concepts

• Cells are the smallest functioning units of life.

• All cells come from pre-existing cells.

• Each cell maintains homeostasis.

Plasma Membrane Functions and Structure

• Functions: Isolation, regulation, sensitivity, structural support.

• Structure: Phospholipid bilayer with hydrophilic heads and hydrophobic tails; contains proteins, carbohydrates, cholesterol.

Cellular Transport Mechanisms

Diffusion and Osmosis

• Diffusion: Movement from high to low concentration.

• Osmosis: Diffusion of water across a selectively permeable membrane.

• Physiological Role: Maintains fluid balance and nutrient/waste exchange.

Carrier-Mediated Transport

• Facilitated Diffusion: Uses carriers, no ATP required.

• Active Transport: Uses carriers, requires ATP.

Cell Organelles and Functions

Non-membranous Organelles

• Cytoskeleton: Shape, movement.

• Microvilli: Surface area for absorption.

• Centrioles: Cell division.

• Cilia: Movement across cell surface.

• Ribosomes: Protein synthesis.

Membranous Organelles

• Endoplasmic Reticulum (ER): Synthesis, storage, transport.

• Golgi Apparatus: Packaging, secretion.

• Lysosomes: Digestion, defense.

• Mitochondria: ATP production.

• Nucleus: Stores genetic information, controls cell activity.

Cell Nucleus and Protein Synthesis

Functions of the Nucleus

• Controls DNA replication and gene expression.

• Directs protein synthesis via mRNA, tRNA, rRNA.

Protein Synthesis

• Transcription: DNA to mRNA in nucleus.

• Translation: mRNA to protein in cytoplasm.

Cell Cycle and Division

Stages and Significance

• Interphase: Cell growth, DNA replication.

• Mitosis: Division of nucleus.

• Cytokinesis: Division of cytoplasm.

High-Energy Compounds and Cellular Energy

ATP and Energy Transfer

• ATP (Adenosine Triphosphate): Main energy molecule.

• ATP formation: $ADP + phosphate \rightarrow ATP + energy$

• ATP powers cellular work: muscle contraction, active transport, synthesis.

Relationship Between Chemicals and Cells

Macromolecules and Nucleic Acids

• Proteins: Enzymes, support, movement, communication.

• Carbohydrates: Energy, cell structure.

• Lipids: Membranes, energy storage.

• Nucleic Acids: DNA and RNA; store and transmit genetic information.

DNA and RNA Structure

• DNA: Double helix, bases A-T, C-G.

• RNA: Single strand, bases A-U, C-G.

Types and Functions of RNA

• mRNA: Carries genetic code from DNA to ribosome.

• tRNA: Brings amino acids for protein synthesis.

• rRNA: Forms part of ribosome structure.

Summary Table: Major Organelles and Functions

Organelle	Main Function
Cytoskeleton	Shape, movement
Ribosomes	Protein synthesis
ER (Rough/Smooth)	Protein/lipid synthesis
Golgi Apparatus	Packaging, secretion
Lysosomes	Digestion, defense
Mitochondria	ATP production
Nucleus	Genetic information, control

Additional info:

• Some content inferred for completeness, such as the summary table and expanded explanations of organelle functions.