Chapter 1: Introduction to Physiology

Define Physiology

Physiology is the study of the normal functioning of a living organism and its component parts. It explores how biological systems carry out their functions to maintain life.

Levels of Organization from Atoms to the Biosphere

Biological organization is hierarchical, ranging from the smallest chemical units to the largest ecological systems.

• Atoms

• Molecules

• Cells

• Tissues

• Organs

• Organ systems

• Organisms

• Population of one species

• Ecosystem of different species

• Biosphere

Mechanistic vs. Teleological Explanations

Mechanistic explanations describe "how" a process occurs, focusing on the steps and mechanisms involved. Teleological explanations describe "why" a process occurs, focusing on its purpose or end result.

• Example (Mechanistic): How do red blood cells transport oxygen? — By binding oxygen to hemoglobin.

• Example (Teleological): Why do red blood cells transport oxygen? — To supply tissues with oxygen for metabolism.

10 Physiological Organ Systems of the Body

The human body is organized into ten major physiological organ systems, each with distinct functions.

1. Respiratory (Pulmonary)

2. Urinary (Renal)

3. Digestive (Gastrointestinal)

4. Nervous

5. Reproductive

6. Lymphatic (Immune)

7. Integumentary

8. Endocrine

9. Musculoskeletal

10. Circulatory (Cardiovascular)

Functions of the 10 Physiological Organ Systems

• Respiratory: Exchange of oxygen and carbon dioxide between internal and external environments.

• Urinary/Renal: Maintenance of water and solutes in the internal environment; waste removal.

• Nervous: Coordination of the body's function through electrical signals and the release of regulatory molecules.

• Musculoskeletal: Support and movement.

• Immune: Defense against foreign invaders.

• Integumentary: Protection from the external environment.

• Digestive: Conversion of food into particles that can be transported into the body; elimination of some wastes.

• Endocrine: Coordination of body function through the synthesis and release of regulatory molecules.

• Cardiovascular: Transport of materials between all cells of the body.

Homeostasis

Homeostasis is the maintenance of a relatively stable internal environment. It is essential for the survival of organisms.

• What happens when homeostasis fails? The body enters a state of illness or disease, known as a pathological condition.

Major Compartments of the Human Body

• Extracellular fluid (ECF): Fluid outside the cells.

• Intracellular fluid (ICF): Fluid within the cells.

Law of Mass Balance

The law of mass balance states that the amount of a substance that remains constant in any system is offset by an equal loss.

• Equation:

Components of a Control System

• Input signal

• Integrated center — "Gland processing that information"

• Output signal — "Tells target to behave"

Feedback Mechanisms

Feedback mechanisms regulate physiological processes.

• Negative feedback: Feedback loop that reverses a stimulus and returns the system to normal.

• Positive feedback: Feedback loop that reinforces a stimulus, driving the system further from its starting state.

• Feedforward control: Allows the body to anticipate change and make certain adjustments.

Examples: Childbirth, defecation, urination, clotting, lactation, and vomiting are all examples of positive feedback. Our body's temperature regulation is an example of negative feedback.

Placebo and Nocebo Effects

• Placebo: Inactive substance taken during a study, proposed as the actual drug to alleviate some problem.

• Nocebo: When people warned about side effects experience them at a higher rate than those not warned.

Experimental Studies and Outcomes

Double-blind studies and controls are important to eliminate bias and accurately measure the effects of treatments.

Chapter 2: Molecule Interactions

Four Major Groups of Biomolecules

• Covalent bonds

• Ionic bonds

• High-energy electrons

• Free radicals

Composition, Structure, and Functions of Biomolecules

• Covalent bonds: Atoms share electrons in the outer shell, forming strong bonds. Basis for electrical signaling in the body.

• Ions: Electrons that allow energy to be used for synthesis, movement, and other life processes.

• High-energy electrons: Contribute to aging and the development of certain diseases and cancers.

• Free radicals: Highly reactive, can damage cells.

Types of Covalent and Noncovalent Bonds

• Covalent: Strong, includes nonpolar and polar molecules.

• Noncovalent: Weak, includes ionic, hydrogen, and Van der Waals forces.

Structure of Soluble and Polar Molecules

• Polar molecules: Have an uneven distribution of electrons (e.g., water).

• Nonpolar molecules: Even distribution of electrons (e.g., carbon and hydrogen).

Molecular Shape and Function

The three-dimensional shape of a molecule can be characterized by its bonds and angles.

• Example: Double bond, kink, fatty acid chain.

Acids, Bases, and Buffers

• Acids: Release hydrogen ions (H+).

• Bases: Accept hydrogen ions.

• Buffers: Stabilize pH by absorbing or releasing H+.

pH Equation:

pH varies from 0 (very acidic) to 14 (very basic).

Functions of Soluble Proteins in the Body

• Metabolism

• Movement across cell surface

• Cell-to-cell communication

• Immune responses

• Bind and protect body from foreign invaders

• Cell movement

• Processes of up and down

Chapter 3: Compartments (Cells and Tissues)

Major Body Cavities and Compartments

• Cranial cavity: Brain

• Thoracic cavity: Pleural sac, pericardial sac

• Abdominopelvic cavity: Abdominal and pelvic cavities

Functions of Organelles in Animal Cells

• Mitochondria: Make ATP

• Rough endoplasmic reticulum (RER): Synthesis of proteins

• Smooth endoplasmic reticulum (SER): Synthesis of fatty acids, steroids, carbohydrates, and lipids

• Golgi apparatus: Sort, modify, and package proteins into vesicles

• Lysosomes: Break down bacteria and old organelles

• Peroxisomes: Break down fatty acids and toxic materials

Cell Structures: Cilia, Flagella, and Microvilli

• Cilia: Move with a wave-like pattern, sweeping motion

• Flagella: Move back and forth, e.g., sperm

• Microvilli: Do not move, but increase surface area for absorption

Organization and Function of the Nucleus

• Contains DNA, nucleolus, nuclear pores, nuclear matrix, and chromatin

• Controls cell activities and stores genetic information

Proteins in Cell Junctions

• Gap junctions: Allow direct cell-to-cell communication

• Tight junctions: Hold cells together and connect them to the extracellular matrix

• Desmosomes: Provide structural support

Four Tissue Types

• Epithelial: Covers internal and external surfaces

• Connective: Supports and connects other tissues

• Muscle: Provides movement

• Nervous: Controls body functions and communication

Five Functional Categories of Epithelia

• Protection

• Absorption

• Filtration

• Secretion

• Sensory reception

Seven Main Categories of Connective Tissue

• Protecting

• Enclosing/separating

• Connecting

• Supporting/moving

• Storing

• Cushioning/insulating

Organs of the 10 Physiological Organ Systems and Their Tissue Types

Study Prep Q&A

• Anterior cavity: Ventricular cavity "in front"

• Posterior cavity: Dorsal cavity "back"

• Neurons vs. Neuroglia: Neurons conduct electrical impulses; neuroglia support and protect neurons.

• Homeostasis: The process by which the body maintains a stable internal environment despite external changes.

• Order of levels of organization (smallest to largest): Atom, molecule, cell, tissue, organ, organ system, organism, biosphere.

• pH equation:

• Negative feedback example: Regulation of blood glucose levels by insulin and glucagon.

Additional info: Some explanations and examples have been expanded for clarity and completeness.