Introduction to Anatomy and Physiology

Definition of Anatomy and Physiology

Anatomy is the study of the structure of body parts and their relationships to one another. Physiology is the study of the function of the body’s structural machinery.

• Anatomy: Focuses on body structures, such as organs, tissues, and cells.

• Physiology: Explains how those structures work and interact to sustain life.

• Example: Studying the heart’s chambers (anatomy) and how the heart pumps blood (physiology).

Organization of the Human Body

Organ Systems

The human body is organized into several organ systems, each with specific functions and associated organs.

• Major Organ Systems:

  • Integumentary System: Skin, hair, nails; protects body, regulates temperature.

  • Skeletal System: Bones, joints; supports and protects organs, enables movement.

  • Muscular System: Muscles; movement, posture, heat production.

  • Nervous System: Brain, spinal cord, nerves; fast-acting control system.

  • Endocrine System: Glands; hormone production, regulation of growth and metabolism.

  • Cardiovascular System: Heart, blood vessels; transports nutrients and gases.

  • Lymphatic System: Lymph nodes, vessels; immune response, fluid balance.

  • Respiratory System: Lungs, airways; gas exchange (O2 and CO2).

  • Digestive System: Stomach, intestines; breakdown and absorption of food.

  • Urinary System: Kidneys, bladder; waste elimination, water balance.

  • Reproductive System: Ovaries/testes; production of offspring.

• Function: Each system contributes to homeostasis and overall health.

Genetic Information and Protein Synthesis

Start and Stop Codons in mRNA

Start and stop codons are specific sequences in mRNA that signal the beginning and end of protein synthesis.

• Start Codon: AUG (codes for methionine; signals initiation of translation).

• Stop Codons: UAA, UAG, UGA (signal termination of translation).

Feedback Mechanisms

Positive and Negative Feedback

Feedback mechanisms regulate physiological processes to maintain homeostasis.

• Negative Feedback: Reduces the effect of the original stimulus (e.g., body temperature regulation).

• Positive Feedback: Enhances the original stimulus (e.g., blood clotting, childbirth contractions).

• Example: When blood glucose rises, insulin is released to lower it (negative feedback).

Body Organization and Orientation

Body Quadrants and Planes

• Quadrants: The abdomen is divided into four quadrants: right upper, left upper, right lower, left lower.

• Planes: Imaginary lines dividing the body:

  • Sagittal Plane: Divides body into left and right.

  • Frontal (Coronal) Plane: Divides body into anterior and posterior.

  • Transverse Plane: Divides body into superior and inferior.

Homeostasis

Concepts of Homeostasis

Homeostasis is the maintenance of a stable internal environment despite external changes.

• Components: Receptor (detects change), Control Center (processes information), Effector (responds to change).

• Example: Regulation of body temperature, blood pH, and glucose levels.

Chemical Reactions in Physiology

Catabolism and Anabolism

• Catabolism: Breakdown of complex molecules into simpler ones, releasing energy.

• Anabolism: Synthesis of complex molecules from simpler ones, requiring energy.

• Example: Digestion (catabolic), protein synthesis (anabolic).

Cell Membrane and Transport

Cell Membrane Functions

• Functions: Selective barrier, communication, transport, cell recognition.

• Plasma Membrane Characteristics: Phospholipid bilayer, embedded proteins, cholesterol.

Movement Across Membranes

• Osmosis: Movement of water across a semipermeable membrane.

• Diffusion: Movement of molecules from high to low concentration.

• Facilitated Diffusion: Passive transport via membrane proteins.

• Active Transport: Movement against concentration gradient, requires energy (ATP).

• Endocytosis: Uptake of materials via vesicles (e.g., clathrin-coated pits).

• Exocytosis: Release of materials from cells.

Types of Solutions

• Isotonic: Equal solute concentration inside and outside the cell.

• Hypertonic: Higher solute concentration outside; cell shrinks.

• Hypotonic: Lower solute concentration outside; cell swells.

Membrane Potential

• Definition: Electrical charge difference across the cell membrane due to ion distribution.

• Key Point: Created by movement of ions, especially Na+ and K+.

Cellular Organelles

General Functions

• Membrane-bound Organelles: Nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes.

• Non-membrane-bound Organelles: Ribosomes, cytoskeleton, centrioles.

Body Cavities

Major Cavities and Their Contents

• Pericardial Cavity: Contains the heart.

• Pleural Cavities: Contain the lungs.

• Peritoneal Cavity: Contains abdominal organs.

Chemical Bonds

Types of Bonds

• Ionic Bond: Transfer of electrons between atoms.

• Covalent Bond: Sharing of electrons between atoms.

• Hydrogen Bond: Weak attraction between a hydrogen atom and an electronegative atom.

Cell Division

Phases of Mitosis

• Prophase: Chromosomes condense, spindle forms.

• Metaphase: Chromosomes align at the cell equator.

• Anaphase: Sister chromatids separate to opposite poles.

• Telophase: Nuclear envelopes reform, chromosomes decondense.

Elements and Water Properties

Definition of an Element

• Element: Substance consisting of one type of atom, defined by the number of protons.

Water Properties

• Surface Tension: Cohesion of water molecules at the surface due to hydrogen bonding.

• Importance: Allows small objects to rest on water and contributes to capillary action.

Macromolecules and Protein Structure

Carbohydrate Storage

• Glycogen: Polysaccharide stored in the liver and muscles for energy.

V-snares, T-snares, and Clathrin

• V-snares and T-snares: Proteins involved in vesicle fusion during exocytosis and endocytosis.

• Clathrin: Protein that forms coated pits for vesicle formation.

Levels of Protein Structure

Cell Signaling

G-Protein Linked Second Messenger Systems

• Location: Found in cell membranes; involved in transmitting signals from receptors to target molecules inside the cell.

• Function: Activate intracellular signaling pathways (e.g., cAMP pathway).

Summary Table: Types of Chemical Bonds