Anatomy & Physiology 1 Unit 1: Introduction, Basic Chemistry, Cell Structure & Function

Introduction to Anatomy & Physiology

Overview

Anatomy & Physiology is the study of the structure and function of the human body. Understanding both aspects is essential for predicting how the body works and responds to changes.

• Anatomy: Study of structure, including gross (visible) and microscopic (cellular/tissue) levels.

• Physiology: Study of function, focusing on how structures work together to sustain life.

• Structure vs. Function: The physical structure of a body part determines its function. For example, the hinge structure of the elbow allows for flexion and extension.

Characteristics of Living Things

• All living things share common characteristics, such as organization, metabolism, responsiveness, growth, and reproduction.

• These characteristics allow predictions about structure and function.

• Four essential processes: metabolism, responsiveness, movement, and reproduction.

Levels of Organization

Hierarchical Structure

The human body is organized into increasingly complex levels:

• Chemical Level: Atoms and molecules

• Cellular Level: Cells (smallest living units)

• Tissue Level: Groups of similar cells performing specific functions

• Organ Level: Structures composed of multiple tissue types

• Organ System Level: Groups of organs working together

• Organism Level: The complete living being

Chemical Level of Organization

Atoms and Molecules

• Atoms: Smallest stable units of matter

• Molecules: Combinations of atoms bonded together

• Types of Bonds: Covalent, ionic, and hydrogen bonds

• The behavior of molecules is determined by their shape and atomic composition.

• Enzymes: Proteins that catalyze chemical reactions; their function depends on their shape.

• Macromolecules: Four main types: carbohydrates, proteins, lipids, nucleic acids

Cellular Level of Organization

Cell Structure and Function

• Cells: Smallest living units; humans have ~200 types.

• Cells differentiate and specialize through mitosis.

• Measured in micrometers; each cell responds to its local environment.

• Organelles: Specialized structures within cells, each with a specific function (e.g., mitochondria produce ATP).

Basic Principles of Cell Theory

• Cells are the structural building blocks of all plants and animals.

• Cells arise from the division of pre-existing cells.

• Cells are the smallest units that perform all vital functions.

Cell Function and Structure

• The shape of a cell is closely related to its function (e.g., nerve cells have long extensions for transmitting signals).

Tissue Level of Organization

Types of Tissues

Groups of similar cells working together form tissues. There are four primary tissue types:

• Epithelial Tissue: Forms barriers, covers surfaces, lines cavities, and produces secretions.

• Connective Tissue: Provides support, stores energy, and connects other tissues. Contains cells in an extracellular matrix.

• Muscle Tissue: Contracts to produce movement, maintain blood flow, and stabilize body temperature.

• Nervous Tissue: Transmits information via electrical impulses; consists of neurons and supporting neuroglia.

Organ Level of Organization

Organs and Their Functions

• Organs are functional units composed of multiple tissue types.

• Function is determined by the structure and organization of tissues.

• Most organs contain all four tissue types, each contributing to the organ's overall function.

Organ Systems

Overview of Human Organ Systems

The human body has 11 organ systems, each with specific functions and interdependence:

• Integumentary System: Protection, temperature regulation

• Skeletal System: Support, movement, blood cell production

• Muscular System: Movement, support, heat production

• Nervous System: Control, communication, integration

• Endocrine System: Hormone production, regulation

• Cardiovascular System: Transport of nutrients, gases, wastes

• Lymphatic System: Defense, fluid balance

• Respiratory System: Gas exchange

• Digestive System: Nutrient breakdown and absorption

• Urinary System: Waste elimination, water balance

• Reproductive System: Production of offspring

Homeostasis

Maintaining Internal Stability

• Homeostasis is the maintenance of a stable internal environment.

• Critical values (e.g., blood pH, temperature) must remain within narrow ranges.

• Failure to maintain homeostasis leads to illness or death.

• Homeostatic Regulation: Physiological processes that maintain stability despite external changes.

Components of Homeostatic Regulatory Mechanism

• Receptor: Senses changes in conditions (stimulus)

• Control Center: Processes information and sends commands

• Effector: Responds to commands to address the stimulus

Types of Feedback

• Negative Feedback: Most common; effector opposes the original stimulus, minimizing change (e.g., temperature regulation).

• Positive Feedback: Less common; effector enhances the original stimulus, producing extreme responses (e.g., labor contractions, blood clotting).

Anatomical Terms

Language of Anatomy

• Anatomical Position: Standing upright, hands at sides, palms forward, feet together, eyes forward.

• Directional Terms: Superior, inferior, anterior, posterior, medial, lateral, proximal, distal, cranial, caudal.

• Sectional Terms: Frontal (coronal), sagittal, transverse (horizontal) planes.

Body Cavities

• Body cavities protect organs and allow for changes in organ size and shape.

• Major cavities: thoracic (pleural, pericardial), abdominopelvic (peritoneal, retroperitoneal, pelvic).

Basic Chemistry for Anatomy & Physiology

Elements and Their Roles

• Major Elements: Oxygen, carbon, hydrogen, nitrogen (found in all living things and macromolecules).

• Calcium: Essential for bones, blood calcium levels, muscle contraction, neuron function.

• Phosphorus: Important for nucleic acids and bone structure.

• Sodium & Potassium: Crucial for muscle and nerve cell function, membrane potential.

• Trace Elements: Often cofactors in enzymatic reactions.

Element	Significance
Oxygen	Component of water and organic molecules; required for ATP production
Carbon	Backbone of organic molecules
Hydrogen	Component of water and most organic molecules
Nitrogen	Component of proteins and nucleic acids
Calcium	Structural component of bones; required for muscle contraction
Phosphorus	Component of nucleic acids and bone
Sodium & Potassium	Essential for nerve impulse transmission and muscle contraction

Atomic Structure and Chemical Bonds

• Atomic Number: Number of protons

• Mass Number: Protons + neutrons

• Atomic Weight: Average mass of atoms

• Ionic Bonds: Electrons transferred; forms ions (cations and anions)

• Covalent Bonds: Electrons shared; forms molecules

• Hydrogen Bonds: Weak attractions between molecules, important for water and DNA structure

Water and pH

• Water: Polar molecule; hydrogen bonds give water unique properties

• Electrolytes: Inorganic compounds that dissolve in water, important for cell function

• pH: Measure of hydrogen ion concentration; scale is logarithmic

• Acidosis: Blood pH below 7.35

• Alkalosis: Blood pH above 7.45

• Buffers: Stabilize pH by removing or replacing hydrogen ions

Chemical Reactions

• Reactants: Starting materials

• Products: Resulting substances

• Metabolism: Sum of all chemical reactions in the body

• Anabolism: Building larger molecules

• Catabolism: Breaking down molecules

• Decomposition: Breaking molecules into smaller fragments

• Synthesis: Combining smaller fragments into larger molecules

• Exchange: Shuffling parts of molecules to produce new products

Organic Molecules

Macromolecules

• Carbohydrates: Energy source; monomer is glucose

• Lipids: Energy storage, cell membrane structure; includes phospholipids and cholesterol

• Proteins: Most abundant organic molecule; monomer is amino acid; structure determines function

• Nucleic Acids: DNA and RNA; store and transfer genetic information

Enzymes

• Proteins that catalyze chemical reactions by lowering activation energy

• Highly specific; function depends on shape (active site, substrate, product)

• Factors affecting enzyme activity: temperature, pH, salinity, concentration

ATP

• Adenosine Triphosphate (ATP): Main energy currency of the cell

Cells and Organelles

Cell Theory

• Cells are the basic unit of life

• Cells differentiate and specialize via gene expression

Cell Structure

• Plasma Membrane: Selectively permeable barrier

• Cytoplasm: Contains cytosol and organelles

• Nucleus: Contains genetic material; controls protein synthesis

• Nucleolus: Site of ribosome production

• Vesicles: Membrane-bound sacs for transport

• Peroxisomes & Lysosomes: Membranous organelles for breakdown and recycling

• Ribosomes: Sites of protein synthesis

• Endoplasmic Reticulum (ER): Rough (with ribosomes) for protein synthesis; smooth for lipid synthesis

• Golgi Apparatus: Modifies, sorts, and packages proteins and lipids

• Mitochondria: Site of ATP production via aerobic respiration

• Cytoskeleton: Provides structural support and flexibility

Protein Synthesis

• Transcription: DNA to mRNA in the nucleus

• Translation: mRNA to protein in the cytoplasm

Cell Membrane Structure & Transport

Membrane Structure

• Composed of phospholipids, proteins, and cholesterol

• Selective permeability allows regulation of material movement

Transport Mechanisms

• Passive Transport: No ATP required; includes diffusion, facilitated diffusion, and osmosis

• Active Transport: Requires ATP; moves substances against concentration gradient (e.g., Na+/K+ pump)

• Bulk Transport: Endocytosis and exocytosis for large quantities

Cell Cycle and Division

Phases of the Cell Cycle

• Interphase: G1 (growth), S (DNA replication), G2 (preparation for division)

• Mitosis: Prophase, metaphase, anaphase, telophase

• Cytokinesis: Division of cytoplasm

• Cell division is tightly regulated; uncontrolled division leads to cancer

Study Tips

• Make vocabulary lists and ensure understanding of definitions and concepts

• Break down processes into steps and sequence them

• Use flashcards and study guides

• Review guided notes and artwork for better comprehension

• Space out study sessions for better retention