Introduction to Human Anatomy & Physiology: Foundational Concepts and Life Functions

Overview of Anatomy and Physiology

Definitions and Scope

• Anatomy: The study of the structure of body parts and their relationships to one another. It answers questions such as 'Where is it?' and 'What does it look like?'

• Physiology: The study of the function of body parts; it explains how the body works.

Topics of Anatomy

Major Subfields

• Gross/Macroscopic Anatomy: Study of large structures visible to the naked eye. Includes:

  • Regional Anatomy: Focuses on specific areas of the body.

  • Systemic Anatomy: Studies body systems.

  • Surface Anatomy: Examines external features.

• Microscopic Anatomy: Study of structures too small to be seen without magnification. Includes:

  • Cytology: Study of cells.

  • Histology: Study of tissues.

• Developmental Anatomy: Examines structural changes throughout the lifespan.

Methods to Study Anatomy

• Mastery of anatomical terminology

• Observation

• Manipulation

• Palpation (feeling organs with hands)

• Auscultation (listening to organ sounds)

Topics of Physiology

Major Subfields

• Renal Physiology: Function of kidneys

• Neurophysiology: Function of the nervous system

• Cardiovascular Physiology: Function of the heart and blood vessels

• Muscular Physiology: Function of muscles

Methods to Study Physiology

• Ability to focus at many levels (systemic, cellular, molecular)

• Study of basic physical principles (e.g., electrical currents, pressure, movement)

• Study of basic chemical principles

Principle of Complementarity of Structure and Function

Structure Dictates Function

• The function of a body part depends on its structure.

• Structures are formed in a way that enables their specific function.

• Example: Bones are rigid to support and protect organs; muscle cells are elongated for contraction.

Levels of Structural Organization

Hierarchy from Simple to Complex

• Chemical Level: Atoms combine to form molecules. $\text{Atoms} \rightarrow \text{Molecules}$

• Cellular Level: Cells are made up of molecules and organelles.

• Tissue Level: Tissues consist of similar types of cells.

• Organ Level: Organs are made up of different types of tissues.

• Organ System Level: Organ systems consist of different organs that work together closely.

• Organismal Level: The human organism is made up of many organ systems.

Necessary Life Functions

Essential Processes for Survival

• Maintaining Boundaries: Separation of internal and external environments.

  • Cell membranes

  • Integumentary system (skin)

• Movement:

  • Of body parts (skeletal muscles)

  • Of substances (cardiac and smooth muscle)

• Responsiveness (Excitability): Ability to sense and respond to stimuli.

  • Withdrawal reflex

  • Control of breathing

• Digestion: Breakdown of food and absorption of nutrients into blood.

• Metabolism: All chemical reactions in body cells.

  • Catabolism: Breakdown of substances

  • Anabolism: Synthesis of complex structures

• Excretion: Removal of wastes from the body.

• Reproduction: Cellular division for growth or repair; production of offspring.

• Growth: Increase in size of body part or organism; construction faster than destruction.

Examples of Life Function Disorders

Duchenne Muscular Dystrophy (DMD)

• Genetic disorder causing alteration in production of dystrophin protein.

• Affects skeletal muscle first, then cardiac and smooth muscle.

Celiac Disease

• Autoimmune disorder damaging intestinal lining after gluten consumption.

• Results in poor absorption of nutrients (fat, calcium, iron, folate).

Gout

• Acute arthritis with intense joint pain, inflammation, and redness.

• Caused by accumulation of urate crystals (from breakdown of purines).

• Kidneys may excrete too little uric acid, leading to crystal buildup.

Alzheimer's Disease

• Neurodegenerative disorder affecting brain structure and function.

• Associated with impaired glucose metabolism and neurofibrillary degeneration.

Functional Grouping of Organ Systems

Major Categories

• Connecting Systems: Cardiovascular, Lymphatic

• Movement of Matter: Digestive, Respiratory, Urinary

• Control of Body: Endocrine, Nervous

• Support and Movement: Skeletal, Muscular

• Protection: Integumentary, Lymphatic

• Continuity of Species: Reproductive

Survival Needs

Requirements for Life

• Nutrients: Chemicals for energy and cell building (carbohydrates, fats, proteins, minerals, vitamins)

• Oxygen: Essential for ATP production

• Water: Most abundant chemical; fluid base for reactions, secretions, excretions

• Normal Body Temperature: 37°C; affects rate of chemical reactions

• Appropriate Atmospheric Pressure: Required for breathing and gas exchange

Homeostasis

Definition and Mechanisms

• Maintenance of relatively stable internal conditions despite environmental changes

• Dynamic state of equilibrium

• Maintained by all organ systems

Homeostatic Control Mechanisms

• Receptor (Sensor): Monitors environment and detects changes

• Control Center: Determines set point, receives input, decides response

• Effector: Carries out response to restore balance

Feedback Mechanisms

• Negative Feedback:

  • Reduces or shuts off original stimulus

  • Variable changes in opposite direction

  • Examples: Regulation of body temperature, blood glucose by insulin

• Positive Feedback:

  • Enhances or exaggerates original stimulus

  • Usually controls infrequent events (e.g., labor contractions, blood clotting)

The Language of Anatomy

Anatomical Position

• Standard reference position for describing locations and directions on the human body

Directional Terms

• Used to describe the location of one body part relative to another

Body Planes

• Sagittal (Median) Plane: Divides body into right and left

• Transverse (Horizontal) Plane: Divides body into superior and inferior

• Coronal (Frontal) Plane: Divides body into ventral (front) and dorsal (back)

Membranes in the Ventral Cavity

• Serous Membranes:

  • Parietal Serosa: Lines cavity walls

  • Visceral Serosa: Covers organs

  • Serous Fluid: Reduces friction

  • Examples: Pericardium (heart), Pleurae (lungs), Peritoneum (abdominal organs)

Abdominopelvic Quadrants

• Used to describe locations of organs in the abdomen

Table: Levels of Structural Organization

Level	Description	Example
Chemical	Atoms combine to form molecules	Water (H2O), Glucose (C6H12O6)
Cellular	Cells are made up of molecules and organelles	Muscle cell, Neuron
Tissue	Groups of similar cells	Muscle tissue, Nervous tissue
Organ	Contains two or more types of tissues	Heart, Liver
Organ System	Organs that work closely together	Cardiovascular system
Organismal	All organ systems	Human body

Additional info:

• Neurogenesis is influenced by factors such as stress, aging, depression, exercise, and disease.

• Alcohol increases inhibition in the nervous system by binding to GABA receptors, dampening excitation.