Anatomy & Physiology: Foundational Concepts and Cellular Chemistry Study Notes

Anatomy & Physiology: Foundational Concepts

Negative Feedback & Positive Feedback

Feedback mechanisms are essential for maintaining homeostasis in biological systems.

• Negative Feedback: A process that reduces or reverses a change to keep a variable within a normal range. Example: Regulation of body temperature.

• Positive Feedback: A process that amplifies a change, moving the system away from its starting state. Example: Blood clotting cascade.

Levels of Organization

Biological systems are organized hierarchically from simplest to most complex.

• Chemical Level: Atoms and molecules

• Cellular Level: Cells and their organelles

• Tissue Level: Groups of similar cells

• Organ Level: Structures composed of multiple tissue types

• Organ System Level: Groups of organs working together

• Organism Level: The complete living being

Anatomical Position

The standard reference position for the body in anatomy.

• Standing upright, facing forward

• Arms at sides, palms facing forward

• Feet together

Serous Membrane – Pleura, Pericardium

Serous membranes line body cavities and cover organs, producing serous fluid for lubrication.

• Pleura: Surrounds the lungs

• Pericardium: Surrounds the heart

Abdominal Pelvic Regions

The abdomen is divided into regions for anatomical study and clinical reference.

• Common divisions: nine regions (e.g., epigastric, umbilical, hypogastric) or four quadrants (RUQ, LUQ, RLQ, LLQ)

Homeostasis

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

• Involves feedback mechanisms

• Critical for survival and function

Characteristics of Life

All living organisms share certain fundamental characteristics.

• Organization

• Metabolism

• Responsiveness

• Growth

• Development

• Reproduction

Sagittal, Frontal, Transverse Sections

Body planes are used to describe anatomical sections.

• Sagittal: Divides body into left and right

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

• Transverse: Divides body into superior and inferior

Body Cavities

Major spaces within the body that house organs.

• Dorsal cavity: Cranial and vertebral cavities

• Ventral cavity: Thoracic and abdominopelvic cavities

Anatomy vs. Physiology

These are the two main branches of biological study.

• Anatomy: Study of structure

• Physiology: Study of function

Basic Chemistry for Anatomy & Physiology

Elements in the Body

Major elements essential for life include:

• Carbon (C)

• Hydrogen (H)

• Oxygen (O)

• Nitrogen (N)

Carbohydrates – Glucose, Glycogen

Carbohydrates are organic molecules that provide energy.

• Glucose: Main energy source for cells

• Glycogen: Storage form of glucose in animals

Electron Numbers in Energy Levels

Electrons are arranged in energy levels (shells) around the nucleus.

• First shell: up to 2 electrons

• Second shell: up to 8 electrons

• Third shell: up to 18 electrons

Organic vs. Inorganic Molecules

Classification based on the presence of carbon.

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

• Inorganic molecules: Usually lack carbon (e.g., water, salts, acids, bases)

Dehydration Synthesis & Hydrolysis (Catabolic/Anabolic Reactions)

Chemical reactions in cells build up or break down molecules.

• Dehydration synthesis (Anabolic): Joins molecules by removing water

• Hydrolysis (Catabolic): Breaks molecules by adding water

Common Chemical Formulas

Understanding chemical formulas is essential for interpreting molecular composition.

• H2O: Water, composed of 2 hydrogen atoms and 1 oxygen atom

• CO2: Carbon dioxide, composed of 1 carbon atom and 2 oxygen atoms

Valence Electrons

Valence electrons are those in the outermost shell and determine chemical reactivity.

• Calculate by using the atomic number and electron configuration

Interpreting Chemical Formulas

Each element symbol is followed by a subscript indicating the number of atoms.

• Example: H2O has 2 hydrogen atoms and 1 oxygen atom

DNA, RNA

Genetic material is composed of nucleic acids.

• DNA (Deoxyribonucleic acid): Stores genetic information

• RNA (Ribonucleic acid): Involved in protein synthesis

Osmosis and Tonicity

Osmosis is the movement of water across a membrane; tonicity describes the effect of solutions on cell volume.

• Isotonic: No net water movement; cell volume remains constant

• Hypotonic: Water enters cell; cell may swell

• Hypertonic: Water leaves cell; cell may shrink

Plasma Membrane Components

The plasma membrane controls entry and exit of substances.

• Phospholipid bilayer

• Proteins (integral and peripheral)

• Cholesterol

• Carbohydrates (glycoproteins, glycolipids)

Biomolecules: Carbohydrates, Proteins, Lipids, Nucleic Acids

Major classes of biological macromolecules:

• Carbohydrates: Monosaccharides (glucose), disaccharides, polysaccharides (glycogen)

• Proteins: Composed of amino acids

• Lipids: Triglycerides (glycerol + 3 fatty acids), phospholipids, steroids

• Nucleic Acids: DNA and RNA, composed of nucleotides (sugar, phosphate, nitrogenous base)

Cell Division: Mitosis

Mitosis is the process of cell division for growth and repair.

• Phases: Prophase, metaphase, anaphase, telophase

• Interphase: Cell grows and DNA replicates

Cell Organelles

Organelles perform specialized functions within the cell.

• Nucleus: Contains genetic material

• Mitochondria: Site of ATP production

• Golgi Apparatus: Modifies and packages proteins

• Ribosomes: Protein synthesis

• Endoplasmic Reticulum: Synthesis and transport of proteins/lipids

Cellular Processes

Cells perform various processes to maintain life.

• Phagocytosis: Cell engulfs particles

• Receptor-mediated endocytosis: Specific uptake of molecules

• Exocytosis: Release of substances from cell

ATP and Cellular Energy

ATP (adenosine triphosphate) is the primary energy carrier in cells.

• ATP is produced mainly in mitochondria

• Required for active transport and cellular work

Atomic Structure: Atomic Number, Atomic Mass

Atoms are composed of protons, neutrons, and electrons.

• Atomic number: Number of protons

• Atomic mass: Number of protons plus neutrons

Labeling a DNA Molecule

DNA is a double helix composed of nucleotides.

• Nucleotide: Phosphate group, deoxyribose sugar, nitrogenous base (A, T, C, G)

Body Cavities

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

• Cranial cavity: Contains the brain

• Thoracic cavity: Contains heart and lungs

• Abdominal cavity: Contains digestive organs

• Pelvic cavity: Contains reproductive organs

Comparison Table: Solution Tonicity Effects on Red Blood Cells

Solution Type	Effect on RBC	Description
Isotonic	No change	Equal solute concentration inside and outside cell
Hypotonic	Swelling/Lysis	Lower solute concentration outside; water enters cell
Hypertonic	Shrinking/Crenation	Higher solute concentration outside; water leaves cell

Key Equations

• ATP Hydrolysis:

• $\text{ATP} + \text{H}_2\text{O} \rightarrow \text{ADP} + \text{P}_i + \text{energy}$

• Atomic Mass Calculation:

• $\text{Atomic Mass} = \text{Number of Protons} + \text{Number of Neutrons}$

Additional info: Academic context and examples have been added to expand upon the original list format and provide a self-contained study guide.