Anatomy and Physiology: Foundations

Definitions and Subdivisions

Anatomy and physiology are core disciplines in understanding the structure and function of the human body. Their subdivisions allow for detailed study of specific systems and processes.

• Anatomy: The study of the structure of body parts and their relationships to one another. Subdivisions include gross anatomy (visible structures), microscopic anatomy (cells and tissues), and developmental anatomy (changes throughout life).

• Physiology: The study of the function of body parts and how they work to carry out life-sustaining activities. Subdivisions include cell physiology, systemic physiology, and pathophysiology.

Complementarity of Structure and Function

The principle of complementarity states that function always reflects structure. What a structure can do depends on its specific form.

• Example: Bones can support and protect because they contain hard mineral deposits.

Levels of Structural Organization

The human body is organized into hierarchical levels, each building upon the previous.

• Chemical level: Atoms combine to form molecules.

• Cellular level: Cells are made up of molecules.

• 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.

Major Body Systems and Their Functions

The body is composed of 11 major organ systems, each with specific components and functions.

• Integumentary: Protects body, regulates temperature (skin, hair, nails).

• Skeletal: Supports and protects organs, stores minerals (bones, joints).

• Muscular: Movement, heat production (muscles).

• Nervous: Fast-acting control, responds to stimuli (brain, spinal cord, nerves).

• Endocrine: Hormone production, regulates processes (glands).

• Cardiovascular: Transports blood, nutrients, gases (heart, blood vessels).

• Lymphatic: Immunity, returns fluids to blood (lymph nodes, spleen).

• Respiratory: Gas exchange (lungs, trachea).

• Digestive: Breaks down food, absorbs nutrients (stomach, intestines).

• Urinary: Eliminates wastes, regulates water (kidneys, bladder).

• Reproductive: Produces offspring (ovaries, testes).

Functional Characteristics Necessary for Life

• Maintaining boundaries

• Movement

• Responsiveness

• Digestion

• Metabolism

• Excretion

• Reproduction

• Growth

Survival Needs of the Human Body

• Nutrients

• Oxygen

• Water

• Normal body temperature

• Atmospheric pressure

Homeostasis and Its Importance

Homeostasis is the maintenance of a stable internal environment despite changes in the external environment. It is vital for proper body function and survival.

• Example: Regulation of body temperature, blood glucose levels.

Feedback Mechanisms

• Negative feedback: Reduces or shuts off the original stimulus (e.g., regulation of blood pressure).

• Positive feedback: Enhances the original stimulus (e.g., blood clotting, labor contractions).

Anatomical Position and Terminology

• Anatomical position: Body erect, feet slightly apart, palms facing forward.

• Directional terms: Superior/inferior, anterior/posterior, medial/lateral, proximal/distal.

• Body planes: Sagittal, frontal (coronal), transverse.

• Surface anatomy landmarks: Specific regions used for reference (e.g., axillary, femoral).

Body Cavities and Their Subdivisions

• Dorsal cavity: Cranial and vertebral cavities (brain, spinal cord).

• Ventral cavity: Thoracic and abdominopelvic cavities (heart, lungs, digestive organs).

Serous Membranes

• Pleura: Surrounds lungs.

• Pericardium: Surrounds heart.

• Peritoneum: Surrounds abdominal organs.

Abdominopelvic Regions and Quadrants

The abdominopelvic cavity is divided for anatomical reference.

Body Chemistry: Essential Concepts

Basic Definitions

• Chemical element: Substance that cannot be broken down by chemical means.

• Atomic number: Number of protons in an atom.

• Atomic mass: Sum of protons and neutrons.

• Atomic weight: Average mass of atoms of an element.

• Isotope: Atoms of the same element with different numbers of neutrons.

• Radioisotope: Isotope with unstable nucleus, emits radiation.

• Anabolism: Synthesis of complex molecules from simpler ones.

• Catabolism: Breakdown of complex molecules into simpler ones.

Major Energy Forms

• Chemical energy: Stored in bonds of chemical substances.

• Electrical energy: Movement of charged particles.

• Mechanical energy: Directly involved in moving matter.

• Radiant energy: Energy that travels in waves (e.g., light).

Elements Forming the Bulk of the Body

• Oxygen (O)

• Carbon (C)

• Hydrogen (H)

• Nitrogen (N)

Atoms and Subatomic Particles

• Atom: Smallest unit of an element retaining its properties.

• Subatomic particles: Protons (+), neutrons (0), electrons (-).

Molecules, Compounds, and Mixtures

• Molecule: Two or more atoms bonded together.

• Compound: Molecule with two or more different elements.

• Mixture: Physical combination of substances.

Chemical Bonding and the Octet Rule

• Electrons: Involved in chemical bonding; atoms seek to fill their outer shell (octet rule).

• Types of bonds: Ionic, covalent, hydrogen.

Polar vs. Nonpolar Compounds

• Polar: Unequal sharing of electrons, partial charges (e.g., water).

• Nonpolar: Equal sharing, no charge separation (e.g., oxygen gas).

Chemical Reactions

• Synthesis:

• Decomposition:

• Exchange:

Oxidation-Reduction (Redox) Reactions

• Oxidation: Loss of electrons.

• Reduction: Gain of electrons.

Factors Affecting Reaction Rates

• Temperature

• Concentration

• Particle size

• Catalysts (enzymes)

Water and Salts in Homeostasis

• Water: Universal solvent, high heat capacity, cushioning.

• Salts: Ionic compounds, conduct electricity, maintain fluid balance.

Acids, Bases, and pH

• Acid: Releases H+ ions.

• Base: Releases OH- ions.

• pH: Measure of H+ concentration;

Dehydration Synthesis and Hydrolysis

• Dehydration synthesis: Removes water to build larger molecules.

• Hydrolysis: Adds water to break down molecules.

Biomolecules: Structure and Function

• Carbohydrates: Energy source; monosaccharides, disaccharides, polysaccharides.

• Lipids: Energy storage, insulation; triglycerides, phospholipids, steroids.

• Proteins: Structure, enzymes; amino acids, polypeptides.

• Nucleic acids: Genetic information; DNA, RNA.

Protein Structure and Denaturation

• Primary: Sequence of amino acids.

• Secondary: Alpha helix, beta sheet.

• Tertiary: 3D folding.

• Quaternary: Multiple polypeptides.

• Denaturation: Loss of structure and function due to environmental changes.

Enzymes

• Function: Biological catalysts, speed up reactions by lowering activation energy.

• Example: Amylase breaks down starch.

RNA vs. DNA

ATP: Structure and Function

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

• Structure: Adenine, ribose, three phosphate groups.

• Function: Releases energy when phosphate bonds are broken: