Chapter 1 A&P

Introduction to Human Anatomy and Physiology

• This chapter serves as an introduction to the fundamental concepts of Human Anatomy and Physiology.

• Importance emphasized: "Because learning changes everything."

History of the Study of the Human Body

• Early healers focused on treating illnesses and injuries.

• Reliance on superstitions and magic transitioned to the use of herbs and natural chemicals for treatment.

• Dissection of cadavers marked the beginning of more systematic study of anatomy and physiology.

• Development of techniques for accurate observations and experimental methods followed.

• The foundational language of anatomy and physiology is based on Greek and Latin.

• The scientific method plays a crucial role in understanding the workings of the body.

Anatomy and Physiology

• Anatomy: Study of the structure (morphology) and organization of the body and its parts.

• Physiology: Study of the functions of these parts and their interactions.

• Close interrelationship: Function is dependent on structure, and vice versa.

• Anatomists use observation and dissection, while physiologists employ experimentation.

Levels of Organization

• All matter, living and non-living, consists of chemicals:

  • Atoms: Smallest unit of chemical structure.

  • Molecules: Two or more atoms bonded together.

  • Macromolecules: Larger particles made of smaller molecules.

• Cells: The smallest units displaying characteristics of life; the human body is made of trillions of cells.

• Tissues: Groups of cells working together.

• Organs: Groups of tissues performing specialized functions.

• Organ Systems: Groups of organs functioning collectively; organisms are composed of multiple organ systems.

Characteristics of Life

• Traits shared by all organisms include:

  • Growth: Increase in size and number of cells.

  • Reproduction: Production of new organisms or cells.

  • Responsiveness: Reaction to changes internally or externally.

  • Movement: Causing position change of the body or its parts.

• Metabolism: Sum of all chemical reactions in the cells, encompasses:

  • Respiration: Energy release from food using oxygen and expelling carbon dioxide.

  • Digestion: Breakdown of food into usable forms.

  • Circulation: Movement of materials in body fluids.

  • Excretion: Removal of metabolic wastes.

Requirements for Maintenance of Life

• Environmental factors:

  • Water: Essential for metabolic processes, transport, and temperature regulation.

  • Oxygen/Carbon Dioxide: Vital for energy release; carbon dioxide is a waste product.

  • Nutrients (Food): Provides energy for bodily functions.

  • Heat: Influences reaction rates in the body.

  • Pressure: Necessary for breathing (atmospheric pressure) and blood circulation (hydrostatic pressure).

Homeostasis

• Definition: Maintenance of a stable internal environment despite external changes.

• Homeostatic mechanisms include:

  • Receptors: Monitor specific changes.

  • Set Points: Normal values or ranges.

  • Effectors: Muscles or glands that restore balance.

• Homeostasis is a self-regulating process, responding to deviations and correcting them, akin to a thermostat.

Components of Homeostatic Mechanisms

• Components:

  • Receptors: Detect deviations from the set point and inform about changes.

  • Set Point: Normal values the body aims to maintain.

  • Effectors: Organs or structures that respond to restore balance.

Feedback Mechanisms

• Negative Feedback: Mechanism to counteract deviations from set points; returns conditions to normal.

  • Example: Thermoregulation in the body.

• Positive Feedback: Mechanism that enhances deviations; less common and usually short-lived.

  • Examples: Blood clotting and childbirth.

Organization of the Human Body

• Body divided into:

  • Axial Portion: Includes head, neck, and trunk.

  • Appendicular Portion: Includes limbs.

• Major cavities:

  • Cranial, Vertebral, Thoracic, and Abdominopelvic Cavity which houses various organs.

Membranes Surrounding Organs

• Double-layered membranes: Parietal layer lines cavity walls; visceral layer covers organs.

  • Example: Pleural, pericardial, and peritoneal membranes separating the respective cavities.

Organ Systems and Homeostasis

• Each organ system contributes to homeostasis through its functions:

  • Integumentary System: Protects, regulates temperature, synthesizes products.

  • Skeletal System: Supports tissues, protects vital organs, and produces blood cells.

  • Muscular System: Facilitates movement and maintains posture.

  • Nervous System: Communicates via neurotransmitters for integration and coordination.

  • Cardiovascular System: Distributes nutrients and oxygen; removes waste.

  • Digestive, Respiratory, and Urinary Systems: Absorb and excrete wastes.

  • Reproductive Systems: Produces offspring.

Anatomical Terminology

• Anatomical Position: Body erect, face forward, arms at sides with palms facing forward.

• Terms of Relative Position:

  • Superior, Inferior, Anterior, Posterior, Medial, Lateral, Bilateral, Ipsilateral, Contralateral, Proximal, Distal, Superficial, Deep.

Terminology of Body Sections

• Major Sections:

  • Sagittal Section: Divides body into right and left.

  • Transverse Section: Divides body into superior and inferior parts.

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

Body Regions of the Abdominal Area

• Nine Regions: Includes epigastric, right and left hypochondriac, umbilical, right and left lateral, pubic, and right and left inguinal regions.

• Four Quadrants: Right upper, right lower, left upper, left lower.