Chapter1a (1)

The Human Body: An Orientation

Chapter 1 Overview

Overview of Anatomy and Physiology

Anatomy

• Definition: The study of structure.

• Subdivisions:

  • Gross or macroscopic anatomy: Includes regional, surface, and systemic anatomy.

  • Microscopic anatomy: Includes cytology (study of cells) and histology (study of tissues).

  • Developmental anatomy: Focuses on embryology (growth and development of an organism).

Essential Tools for Studying Anatomy

• Mastery of anatomical terminology: Understanding terms used in anatomy.

• Observation: Noting physical characteristics and structures.

• Manipulation: Physically examining body structures.

• Palpation: Feeling body parts with hands to determine their condition.

• Auscultation: Listening to the internal sounds of the body, often using a stethoscope.

Physiology

• Definition: The study of function at various levels.

• Subdivisions: Based primarily on organ systems, such as renal (kidneys) and cardiovascular physiology.

Essential Tools for Studying Physiology

• Focus on multiple levels: From systemic to cellular and molecular functions.

• Basic physical principles: Understanding concepts like electrical currents, pressure, and movement.

• Basic chemical principles: Importance of chemical interactions in bodily functions.

Principle of Complementarity

• Inseparability of Anatomy and Physiology: Structure (anatomy) and function (physiology) are deeply intertwined.

• Form Follows Function: A structure's form is determined by its function.

• Examples: Specific forms of anatomical structures enable specific functions.

Levels of Structural Organization

1. Chemical level: Atoms and molecules.

2. Cellular level: Cells and their organelles.

3. Tissue level: Tissues made up of similar types of cells.

4. Organ level: Organs composed of different tissue types.

5. Organ system level: Different organs working together.

6. Organismal level: The entire human organism made up of many organ systems.

Organ Systems of the Body

• 11 Organ Systems: Need to know the name, structures involved, and functions of each system:

  • Integumentary System

  • Skeletal System

  • Muscular System

  • Nervous System

  • Endocrine System

  • Cardiovascular System

  • Lymphatic System/Immunity

  • Respiratory System

  • Digestive System

  • Urinary System

  • Reproductive System

Integumentary System

• Components: Skin, nails, hair.

• Functions: Protects deeper tissues, synthesizes vitamin D, houses receptors and glands.

Skeletal System

• Components: Bones, joints.

• Functions: Protects body organs, provides framework for movement, blood cell formation, mineral storage.

Muscular System

• Components: Skeletal muscles.

• Functions: Facilitates movement and locomotion, maintains posture, produces heat.

Nervous System

• Components: Brain, nerves, spinal cord.

• Functions: Fast-acting control system, responds to changes in the body by activating muscles and glands.

Endocrine System

• Components: Various glands (e.g., pituitary, thyroid, adrenal).

• Functions: Secretes hormones regulating growth, reproduction, and metabolism.

Cardiovascular System

• Components: Heart, blood vessels.

• Functions: Transports blood carrying oxygen, carbon dioxide, nutrients, and wastes.

Lymphatic System/Immunity

• Components: Lymphatic vessels, lymph nodes, spleen.

• Functions: Returns fluid leaked from blood vessels, disposes of debris, houses lymphocytes for immunity.

Respiratory System

• Components: Lungs, airways (e.g., trachea, bronchus).

• Functions: Supplies blood with oxygen and removes carbon dioxide through gas exchange in lungs.

Digestive System

• Components: Stomach, intestines, liver.

• Functions: Breaks down food for absorption; eliminates indigestible waste.

Urinary System

• Components: Kidneys, urinary bladder.

• Functions: Eliminates nitrogenous wastes, regulates water, electrolytes, and acid-base balance.

Male Reproductive System

• Components: Testes, prostate, penis.

• Functions: Production of offspring, sperm production, and delivery.

Female Reproductive System

• Components: Ovaries, uterus, mammary glands.

• Functions: Production of eggs, support for fertilization and fetal development.

Organ Systems Interrelationships

• All organ systems are interconnected.

• Cells depend on organ systems for survival.

• Organ systems cooperate to perform essential life functions.

Necessary Life Functions

1. Maintaining boundaries: Between internal and external environments (e.g., skin).

2. Movement: Includes body parts and substance movement.

3. Responsiveness: Ability to sense and respond to stimuli.

4. Digestion: Breakdown and absorption of nutrients.

5. Metabolism: All chemical reactions, involving catabolism and anabolism.

6. Excretion: Removal of wastes from metabolism and digestion.

7. Reproduction: Cellular division and offspring production.

8. Growth: Increase in size of body parts or organism.

Survival Needs

1. Nutrients: Chemicals for energy and cell building (carbohydrates, fats, proteins, vitamins).

2. Oxygen: Essential for energy release.

3. Water: Most abundant chemical; site of reactions.

4. Normal body temperature: Affects reaction rates.

5. Appropriate atmospheric pressure: Essential for breathing and gas exchange.

Homeostasis

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

• A dynamic state of equilibrium vital for health.

Homeostatic Control Mechanisms

• Continuous monitoring and regulation of variables.

• Nervous and endocrine systems facilitate communication.

Components of a Control Mechanism

1. Receptor (sensor): Monitors and responds to stimuli.

2. Control center: Determines set point and response to stimuli.

3. Effector: Carries out response to restore equilibrium.

Feedback Mechanisms

• Negative Feedback: Reduces the original stimulus, maintaining homeostasis.

  • Example: Body temperature regulation.

• Positive Feedback: Enhances the original stimulus, often leading to a change.

  • Example: Labor contractions during childbirth, blood clotting.

Homeostatic Imbalance

• Any disturbance of homeostasis may result in disease or death.