BIO_221_-_Chapter_1_Sp2024

Chapter 1: An Introduction to the Human Body

• Anatomy and Physiology I

• Dr. Lisa Hight

Anatomy and Physiology

• Anatomy: Study of body structures and relationships among them.

• Physiology: Study of body functions and how the body works.

6 Levels of Structural Organization

• The human body is organized in six levels:

  • Chemical Level: Involves atoms (C, H, O, N, P) and molecules (e.g., DNA).

  • Cellular Level: Individual cells, such as smooth muscle cells.

  • Tissue Level: Groups of similar cells working together (e.g., smooth muscle tissue).

  • Organ Level: Composed of two or more different types of tissues (e.g., stomach).

  • System Level: Groups of organs working together (e.g., digestive system).

  • Organismal Level: The entire human body as a single entity.

Body Systems

• There are 11 body systems, each with specific components and functions that influence one another:

  • Integumentary System

    • Components: Skin, hair, nails, sweat and oil glands.

    • Functions: Protects body, regulates temperature, eliminates wastes, detects sensations.

  • Skeletal System

    • Components: Bones, joints, cartilages.

    • Functions: Supports and protects body, allows movement, produces blood cells, stores minerals and lipids.

  • Muscular System

    • Components: Skeletal muscle tissue.

    • Functions: Involved in body movements, maintains posture, produces heat.

  • Nervous System

    • Components: Brain, spinal cord, nerves, special sense organs.

    • Functions: Generates nerve impulses, responds to changes in the environment.

  • Endocrine System

    • Components: Hormone-producing glands and cells.

    • Functions: Regulates body activities through hormones.

  • Cardiovascular System

    • Components: Heart, blood, and blood vessels.

    • Functions: Pumps blood, transports oxygen, nutrients, and waste.

  • Lymphatic System

    • Components: Lymphatic fluid, vessels, spleen, thymus, lymph nodes, tonsils.

    • Functions: Returns fluids to the blood, contains immune response cells.

  • Respiratory System

    • Components: Lungs, air passageways.

    • Functions: Transfers oxygen and carbon dioxide, regulates acid-base balance.

  • Digestive System

    • Components: Gastrointestinal tract organs and accessory organs (e.g., liver, pancreas).

    • Functions: Breaks down food, absorbs nutrients, eliminates wastes.

  • Urinary System

    • Components: Kidneys, ureters, urinary bladder, urethra.

    • Functions: Produces and eliminates urine, regulates blood composition.

  • Reproductive System

    • Components: Gonads, reproductive organs.

    • Functions: Produces gametes, hormones, and supports reproduction.

Basic Life Processes

1. Metabolism: Chemical reactions (catabolism/anabolism).

2. Responsiveness: Ability to detect and respond to changes.

3. Movement: Motion of the body or substances within.

4. Growth: Increase in size or number of cells.

5. Differentiation: Development of specialized functions.

6. Reproduction: Formation of new organisms.

Homeostasis

• Condition of equilibrium within the body’s internal environment, maintained through regulatory processes.

Body Fluids

• Intracellular Fluid (ICF): Fluid within cells.

• Extracellular Fluid (ECF): Fluid outside cells, includes:

  • Interstitial fluid

  • Blood plasma

  • Lymph

  • Cerebrospinal fluid

  • Synovial fluid

  • Aqueous humor

  • Vitreous body

Homeostatic Imbalances

• Disorder: Any abnormality in structure or function.

• Disease: Specific illness characterized by recognizable signs and symptoms.

  • Symptoms: Subjective changes, not observable.

  • Signs: Objective changes observable by others.

Control of Homeostasis

• Disruptions can be external or internal.

• Regulating Systems:

  • Nervous System: Sends nerve impulses to organs.

  • Endocrine System: Secretes hormones into the blood.

Feedback Systems

• Homeostasis is monitored and regulated:

  • Receptor: Monitors conditions and sends input.

  • Control Center: Evaluates input and generates output command.

  • Effector: Receives output and produces response.

Types of Feedback Systems

• Negative Feedback: Reverses changes to restore homeostasis (e.g., blood pressure regulation).

• Positive Feedback: Reinforces changes (e.g., childbirth, labor contractions).

Anatomical Terminology

• Anatomical Position: Standard position (standing upright, facing forward).

• Prone: Lying face down.

• Supine: Lying face up.

• Major regions:

  • Head

  • Neck

  • Trunk

  • Upper limbs

  • Lower limbs

Directional Terms

• Superior: Above or toward the head.

• Inferior: Below or toward the feet.

• Anterior: Front of the body.

• Posterior: Back of the body.

• Medial: Closer to the midline.

• Lateral: Farther from the midline.

• Proximal: Closer to attachment of a limb.

• Distal: Farther from attachment of a limb.

• Superficial: On the surface of the body.

• Deep: Away from the surface.

Body Cavities

• Cranial Cavity: Contains the brain.

• Vertebral Canal: Surrounds the spinal cord.

• Thoracic Cavity: Contains lungs, heart.

• Abdominopelvic Cavity: Contains various organs (abdominal and pelvic regions).

Quadrants and Regions

• Abdominopelvic regions divided into:

  • Right Hypochondriac Region

  • Right Lumbar Region

  • Right Inguinal Region

  • Epigastric Region

  • Umbilical Region

  • Hypogastric Region

  • Left Hypochondriac Region

  • Left Lumbar Region

  • Left Inguinal Region

Common Medical Imaging Procedures

• Radiography: X-rays for imaging.

• MRI: Magnetic resonance for soft tissues.

• CT Scan: Computerized imaging for detailed structures.

• Ultrasound: Sound waves to visualize organs and fluids.