Bio163: Ch 1 Notes

Overview of Physiology and Anatomy

  • Definitions

    • Physiology: The study of functions of living organisms and their parts.

    • Suffix “-logy” from Latin means "study".

    • Example: Physiology covers bodily functions, including bowel movements.

    • Anatomy: The study of body structures and parts.

    • Typically involves practical learning in labs, focusing on bones and muscles.

The Interconnection of Anatomy and Physiology

  • The fields of anatomy and physiology are closely related; one cannot exist without the other.

    • Example: A broken arm bone affects the function of the arm.

Levels of Organization in Humans

  • Hierarchy of Structure: Movement from microscopic to macroscopic levels.

    1. Atoms

    • Example of atoms: Hydrogen, Oxygen, Carbon.

    1. Molecules

    • Formed by a union of atoms; example: Water (H₂O).

    1. Macromolecules

    • Large molecules composed of smaller ones. Examples:

      • Carbohydrates

      • Lipids

      • Proteins

      • Nucleic acids

    1. Cells

    • Smallest unit of life. Life emerges at this level.

    1. Tissues

    • Groups of similar cells performing a common function. Four main types:

      • Epithelial

      • Connective

      • Muscle

      • Nervous

    1. Organs

    • Structures made of different tissues serving a specific function.

      • Example organs: Stomach, Heart, Liver.

    1. Organ Systems

    • Groups of organs working together. Typical human systems include:

      • Cardiovascular

      • Digestive

      • Respiratory

      • Nervous

      • Endocrine

      • Lymphatic

      • Urinary

      • Muscular

      • Skeletal

      • Integumentary

      • Reproductive

      • Total: 11 (or 12 if reproductive systems are separated).

    1. Organisms

    • Entire human body, all systems functioning together.

Characteristics of Living Things

  • Eight fundamental characteristics common to all life forms:

    1. Movement: Includes movement of the entire organism and movements within cells.

    2. Responsiveness: Ability to respond to environmental stimuli. Example: Plants bending toward sunlight.

    3. Growth: Increase in size and cells, including cell division.

    4. Reproduction: Ability to produce offspring. Sexual and asexual reproduction.

    5. Respiration: Process of converting nutrients into energy, involving oxygen.

    6. Digestion: Breakdown of complex molecules into simpler forms for absorption.

    7. Circulation: Movement of fluids (e.g., blood, lymph) within the body.

    8. Excretion: Removal of waste products from the body.

  • All these characteristics combine to form the concept of Metabolism: the sum of all chemical processes in an organism necessary for maintaining life.

Requirements for Life

  • Five essential needs for survival:

    1. Oxygen: Vital for cellular respiration, not all organisms require it.

    2. Water: Essential for all biochemical reactions in the body.

    3. Nutrition: Source of energy and nutrients for growth and repair.

    4. Heat: Necessary for maintaining the speed of molecular interactions.

    5. Pressure: Necessary for processes like blood circulation and breathing.

Homeostasis

  • Definition: The ability to maintain a stable internal environment amid external changes.

    • Body systems work together to achieve homeostasis.

    • Example: Regulation of body temperature (normal is around 37°C/98.6°F).

    • Homeostatic Mechanisms consist of three components:

    1. Receptors: Detect changes in the internal environment.

    2. Control Center: Typically the brain; processes information and decides on action.

    3. Effectors: Muscles or glands that respond to the signals from the control center.

  • Feedback Mechanisms

    • Negative Feedback: Returns body to set point by negating change.

    • Example: Body temperature regulation—if temp rises, mechanisms activate to cool the body.

    • Positive Feedback: Amplifies change until a desired outcome is reached.

    • Example: Childbirth—pressure from the baby stretching the cervix triggers more contractions via oxytocin release.

Body Regions and Cavities

  • Regional Divisions:

    1. Axial Region: Consists of head, neck, and trunk.

    2. Appendicular Region: Includes the limbs (arms and legs).

  • Body Cavities:

    • Dorsal Cavity:

    • Superior: Cranial cavity (contains the brain).

    • Inferior: Vertebral cavity (contains the spinal cord).

    • Ventral Cavity:

    • Superior: Thoracic cavity (contains lungs and heart).

      • Subdivisions: Pleural cavities for lungs, pericardial cavity for the heart.

    • Inferior: Abdominopelvic cavity (contains digestive and reproductive organs).

      • Subdivisions: Abdominal cavity and pelvic cavity.

  • Membranes:

    • Visceral Membranes: Cover organs.

    • Parietal Membranes: Line cavities.

    • Example: Pleural membranes for lungs, pericardial membranes for heart, peritoneal membranes for abdominal organs.

Planes and Sections of the Body

  • Transverse Plane: Divides body into superior (upper) and inferior (lower) sections.

  • Sagittal Plane: Divides body into right and left sections; may be median (equal) or parasagittal (unequal).

  • Frontal (Coronal) Plane: Divides body into anterior (front) and posterior (back) sections.