Chapter 1: Introduction to Physiology

Definitions and Core Concepts

• Anatomy: The study of structure in living organisms.

• Physiology: The study of the normal functioning of a living organism and its component parts.

Homeostasis

• Definition: The ability of the body to maintain a relatively constant internal environment.

• Mechanism: Maintained by feedback systems that keep the body’s internal environment stable despite changes in the external environment. Sensors (receptors), control centers, and effectors (muscles, glands, organs) are involved.

Feedback Mechanisms

• Positive Feedback: The output of a system enhances the original stimulus, leading to an escalating response until a specific event stops the cycle. Example: Blood clotting, childbirth.

• Negative Feedback: The body detects a change and activates responses that reverse or counteract that change, bringing conditions back to the normal range. Maintains homeostasis and prevents extreme changes. Example: Regulation of body temperature, blood glucose levels.

Levels of Organization

• Hierarchy: Atom → Cell → Tissue → Organ → Organism

Chapter 2: Molecular Interactions

Chemical Composition of the Human Body

• Major Elements: Oxygen, carbon, hydrogen, nitrogen, calcium, phosphorus.

Acids, Bases, and pH

• Acid: Substance that donates protons (H+).

• Base: Substance that accepts protons (H+).

• pH: A measure of hydrogen ion concentration;

Organic vs. Inorganic Molecules

• Organic: Contain carbon-hydrogen bonds (e.g., carbohydrates, proteins, lipids, nucleic acids).

• Inorganic: Do not contain carbon-hydrogen bonds (e.g., water, salts, acids, bases).

Biochemistry of Biomolecules

• Carbohydrates: Main categories are monosaccharides, disaccharides, and polysaccharides.

• Lipids: Backbone is mostly fatty acids and glycerol. Types include triglycerides, phospholipids, and steroids. Difference between fats and oils: Fats are solid at room temperature; oils are liquid.

• Proteins: Composed of amino acids. Four levels of structure: primary, secondary, tertiary, quaternary.

• Nucleic Acids: Made of nucleotides (phosphate group, sugar, nitrogenous base).

Enzymes

• Definition: Biological catalysts that speed up chemical reactions.

• Lock and Key Model: Substrate fits exactly into the enzyme's active site.

• Denaturation: Loss of enzyme structure and function due to heat, pH, or chemicals.

Chapter 3: Compartmentation: Cells and Tissues

Cell Membranes

• Composition: Mostly lipid and protein, some carbohydrates.

• Purpose: Separates cell contents from the environment, regulates entry/exit of substances.

Cell Organelles and Functions

• Mitochondria: ATP production.

• Rough Endoplasmic Reticulum: Synthesis of proteins.

• Smooth Endoplasmic Reticulum: Synthesis of fatty acids, steroids, lipids.

• Golgi Apparatus: Sorts, modifies, and packages proteins into vesicles.

• Lysosomes: Break down bacteria and old organelles.

Cell Cycle and Division

• Interphase: G1 (cell growth), S (DNA replication), G2 (preparation for mitosis).

• Mitosis: Prophase (chromosomes condense), Metaphase (align at center), Anaphase (separate), Telophase (nuclei reform), Cytokinesis (cell splits).

Cell Death

• Necrosis: Cell injury and lysis, often damaging adjacent cells.

• Apoptosis: Programmed cell death, no effect on adjacent cells.

Diffusion

• Definition: Movement of molecules from higher to lower concentration, does not require energy.

• Factors: Faster with higher concentration gradients, higher temperature, smaller molecules.

Chapter 4: Energy and Cellular Metabolism

Glycolysis and Metabolic Pathways

• Glycolysis: Breakdown of glucose to pyruvate, producing ATP and NADH.

• Electron Transport Chain: Series of proteins in mitochondria that generate ATP using electrons from NADH and FADH2.

• Major Energy Carriers: ATP, NADH, FADH2.

Glycogen Storage and Gluconeogenesis

• Glycogen: Storage form of glucose in liver and muscle.

• Gluconeogenesis: Synthesis of glucose from non-carbohydrate sources.

Transcription and Translation

• Transcription: DNA → mRNA in the nucleus.

• Translation: mRNA → protein at the ribosome. Triplet: 3 DNA bases; Codon: 3 mRNA bases; Anticodon: 3 tRNA bases.

Chapter 5: Membrane Dynamics

Homeostasis vs. Equilibrium

• Homeostasis: Dynamic steady state; compartments have varied concentrations and charges, not equal.

• Equilibrium: All substances and charges are equal across compartments.

Body Fluid Compartments

Osmosis, Osmolarity, Tonicity

• Osmosis: Movement of water from low to high solute concentration.

• Osmolarity: Number of active particles per liter of solution.

• Tonicity: Effect of a solution on cell volume.

• Hypotonic: Cells swell and may burst.

• Hypertonic: Cells shrink and dehydrate.

• Isotonic: No net change in cell volume.

Membrane Transport

• Primary Active Transport: Uses ATP directly (e.g., Na+/K+ pump).

• Secondary Active Transport: Uses potential energy stored in concentration gradients.

• Protein-Mediated Transport: Carrier proteins move polar substances across membranes.

• Transcellular Transport: Through cells, must cross two membranes.

• Paracellular Transport: Through tight junctions between adjacent cells.

Chapter 6: Communication, Integration, and Homeostasis

Cell-to-Cell Communication

• Basic Methods: Gap junctions, contact-dependent signals, autocrine/paracrine signals, endocrine signals (hormones), neural signals.

• Receptor Proteins: Located on cell membranes or inside cells; bind ligands (signaling molecules).

• Signal Transduction: Process by which a signal is converted into a cellular response.

• G-Protein Coupled Receptors (GPCRs): Large family of membrane receptors involved in many signaling pathways.

Chapter 8: Neurons: Cellular and Network Properties

Nervous System Organization

• Divisions: Central nervous system (CNS) and peripheral nervous system (PNS).

• Neuron Parts: Dendrites (receive signals), cell body (integrates signals), axon (transmits signals).

• Synapse: Junction between two neurons; can be chemical or electrical.

• Glial Cells: Support neurons (astrocytes, oligodendrocytes, Schwann cells, microglia).

Membrane Potentials

• Resting Membrane Potential: Electrical charge difference across the cell membrane at rest, typically -70 mV.

• Action Potential: Rapid change in membrane potential that propagates along the axon.

• Threshold: Minimum depolarization needed to trigger an action potential.

• Refractory Period: Time during which a neuron cannot fire another action potential.

Chapter 9: The Central Nervous System

Brain and Spinal Cord Structure

• Gray Matter: Neuron cell bodies, dendrites, unmyelinated axons.

• White Matter: Myelinated axons.

• Meninges: Three layers: dura mater, arachnoid mater, pia mater.

• CSF (Cerebrospinal Fluid): Cushions and nourishes the brain and spinal cord.

• Blood-Brain Barrier: Protects brain from harmful substances in the blood.

Brain Regions and Functions

• Cerebrum: Higher brain functions (language, memory, personality, sensation, etc.).

• Cerebellum: Coordination of movement and balance.

• Brainstem: Controls basic life functions (breathing, heart rate).

Chapter 10: Sensory Physiology

Sensory Receptors and Perception

• Types of Receptors: Touch (mechanoreceptors), temperature (thermoreceptors), pain (nociceptors), chemical (chemoreceptors).

• Perception: Interpretation of sensory information by the brain.

• Special Senses: Vision, hearing, equilibrium, taste, smell.

Hearing and Balance

• Cochlea: Organ of hearing.

• Vestibular Apparatus: Senses head movement and position for balance.

Vision

• Retina: Contains rods (low light) and cones (color vision).

• Phototransduction: Conversion of light into electrical signals.

Chapter 11: Efferent Division: Autonomic and Somatic Motor Control

Autonomic Nervous System

• Controls: Involuntary functions (heart rate, digestion, respiratory rate).

• Divisions: Sympathetic ("fight or flight") and parasympathetic ("rest and digest").

• Neurotransmitters: Acetylcholine (ACh), norepinephrine (NE).

• Receptors: Cholinergic (bind ACh), adrenergic (bind NE).

Somatic Motor Pathway

• Controls: Voluntary movement via skeletal muscles.

• Neurotransmitter: Acetylcholine at the neuromuscular junction.

Additional info: This guide covers foundational concepts in anatomy and physiology, including cell structure, membrane dynamics, neural and sensory physiology, and motor control. It is suitable for exam preparation and as a reference for core topics in a college-level A&P course.