Introduction to Anatomy & Physiology

Anatomy and Physiology are foundational sciences that explore the structure and function of the human body. Anatomy focuses on the physical aspects, such as the size, shape, and location of body parts, while Physiology studies how these structures perform vital functions.

Levels of Organization in the Human Body

Chemical Level

• Atoms combine to form molecules, which are the building blocks of cells.

Cellular Level

• Cells are the smallest living units in the body, performing essential functions such as energy production.

Tissue Level

• Tissues are groups of similar cells working together to perform specific functions.

Organ Level

• Organs consist of two or more tissue types working together for complex functions.

Organ System Level

• Organ systems are groups of organs that work together to perform major functions.

Organism Level

• The organism is a complete living entity.

Cell Parts and Their Functions

• Golgi Apparatus: Stacked membranes that store, alter, and package secretory products and lysosomal enzymes.

• Endoplasmic Reticulum (ER):

  • Rough ER (RER): Has ribosomes; modifies and synthesizes proteins.

  • Smooth ER (SER): Lacks ribosomes; synthesizes lipids and carbohydrates.

• Peroxisomes: Spherical vesicles with enzymes that break down fats and neutralize toxins.

• Mitochondria: Tubular organelles producing 95% of the cell’s ATP (energy).

• Lysosomes: Vesicles with digestive enzymes for removing damaged organelles or pathogens.

• Nucleus: Central sphere controlling metabolism, storing genetic information, and synthesizing proteins.

• Cytoskeleton: Provides structural support and facilitates movement within the cell.

Genetic Material: DNA and RNA

• DNA (Deoxyribonucleic Acid): Double helix composed of adenine (A), thymine (T), cytosine (C), and guanine (G). Stores genetic information for protein synthesis and cellular activities.

• RNA (Ribonucleic Acid): Single strand composed of adenine (A), uracil (U), cytosine (C), and guanine (G). Involved in protein synthesis. The sugar in RNA is ribose.

Cell Cycle

• Interphase: Longest phase where the cell prepares for division.

  • G0 Phase: Cells perform normal functions, do not prepare for division.

  • G1 Phase: Cell grows, produces organelles and proteins.

  • S Phase: DNA replication occurs, duplicating chromosomes.

  • G2 Phase: Cell continues to grow and prepares for mitosis.

• Mitosis: Nuclear division in somatic cells, includes:

  • Prophase: Chromosomes condense and become visible.

  • Metaphase: Chromosomes align at the cell’s equator.

  • Anaphase: Sister chromatids separate and move to opposite poles.

  • Telophase: Nuclear membranes reform around separated chromosomes.

• Cytokinesis: Cytoplasm divides, resulting in two daughter cells.

Types of Membrane Transport

Passive Transport (Does not require energy)

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

• Osmosis: Diffusion of water through a semi-permeable membrane.

• Facilitated Diffusion: Uses carrier proteins to move substances down their concentration gradient without energy.

Active Transport (Requires energy)

• Primary Active Transport: Direct use of ATP (e.g., sodium-potassium pump).

• Secondary Active Transport: Uses energy indirectly, often involving symport or antiport mechanisms.

• Vesicular Transport: Moves larger particles or droplets.

  • Endocytosis: Includes pinocytosis (cell drinking) and phagocytosis (cell eating).

  • Exocytosis: Expels materials from the cell.

Homeostasis and Regulation

Mechanisms of Homeostatic Regulation

• Nervous System: Provides rapid, short-term responses (e.g., increases heart rate during exercise).

• Endocrine System: Releases hormones for longer-term adjustments (e.g., controlling blood volume and composition).

Homeostatic Regulatory Pathways

• Autoregulation: Local level adjustment by cells, tissues, or organs in response to environmental changes.

• Extrinsic Regulation: Involves nervous and endocrine systems for coordinated responses.

Homeostasis is the body's ability to maintain a stable internal environment despite external changes.

Anatomic Directional Terms and Body Regions

• Directional Terms: Anterior, posterior, lateral, medial, proximal, cranial, distal, etc.

• Body Cavities: Dorsal, ventral, spinal, thoracic, etc.

• Body Regions: Lumbar, cephalic, brachial, umbilical, hypogastric, pubic, inguinal, etc.

• Anatomical Landmarks: Ex. mentis, manus, axilla, etc.

Functions of the 11 Body Systems

• Skeletal System: Provides support and protection, stores minerals, forms blood cells.

• Muscular System: Enables movement, provides protection and support, generates heat.

• Nervous System: Directs immediate responses, coordinates activities, interprets sensory information.

• Endocrine System: Directs long-term changes, adjusts metabolic activity, controls developmental changes.

• Cardiovascular System: Distributes blood, nutrients, gases, and helps control body temperature.

• Lymphatic System: Defends against infection and disease, returns fluids to the bloodstream.

Ionic vs. Covalent Bonds

• Ionic Bonds: One atom transfers electrons to another, resulting in a cation (positive) and anion (negative) that attract each other.

• Covalent Bonds: Atoms share electrons, creating a stable molecule.

Characteristics of Water

• Universal Solvent: Water dissolves many substances, crucial for chemical reactions.

• Reactivity: Water participates in chemical reactions, such as hydrolysis and dehydration synthesis.

• High Heat Capacity: Water absorbs/releases heat slowly, stabilizing body temperature.

• High Heat of Vaporization: Evaporation of water from skin removes heat, cooling the body.

• Cushioning and Lubrication: Water cushions organs and lubricates tissues, protecting from damage.

Comparison Table: DNA vs. RNA

Key Equations

• Osmosis (Water Potential): Where is water potential, is solute potential, and is pressure potential.

• Sodium-Potassium Pump (Active Transport):

Histology, Pathological Physiology, and System Physiology

• Histology: Study of tissues and their functions within the body.

• Pathological Physiology: Study of how diseases affect the functions of organs or systems.

• System Physiology: Study of tissues and their functions within the body (often overlaps with histology).

Additional info: These notes provide a concise overview of foundational concepts in Anatomy & Physiology, suitable for exam preparation and review.