Organization of Body Parts & Body Tissues

Organization of Body Parts & Body Tissues

Instructor Information

  • Instructor: JING JING SU (PhD, MSN, BSN)

  • Title: Assistant Professor

  • Institution: School of Nursing, TWC

Study Objectives

  • Familiarize yourself with anatomical and directional terms.

  • Identify and locate body cavities.

  • Name the organs located within each body cavity.

  • Identify the membranes that line each body cavity and cover the organs.

  • Understand the four main types of body tissues and their functions.

Body Organization Levels

  • Cells: Basic units of living things.

  • Tissues: Composed of similar types of cells performing specific functions.

  • Organs: Composed of several tissue types performing particular functions within organ systems.

  • Organ Systems: Groups of organs working together for collective functions.

  • Organism: A complete living entity, such as a human.

Hierarchical Organization

  1. Atoms: 原子

  2. Molecules: 分子

  3. Macromolecules: 大分子

  4. Organelles: 細胞器

  5. Cells: 細胞

  6. Tissue: 組織

  7. Organ: 器官

  8. Organ System: 器官系統

  9. Organism: 生物體

The Body's Smallest Organ

  • Smallest organ:

    • Pineal gland of the brain.

  • Scientist: Dr. Dorothy Hodgkin

    • Achievement: Used X-rays to determine the structure of insulin and won the 1964 Nobel Prize.

  • X-Rays: First used to image bone fractures and gunshot wounds in 1896.

Interesting Facts About the Body

  • Approx. 30 trillion cells in the human body (with a margin of 1-2 billion).

  • Estimated 38 trillion bacterial cells inhabit or are present on the human body.

  • Historically significant findings:

    • Ancient Egyptians learned about anatomy by mummifying people as early as 1600 B.C.E.

    • Leonardo da Vinci measured adult proportions, finding fingertip-to-fingertip distance approximately equals height (illustrated in Vitruvian Man).

    • Herophilus taught one of the first anatomy classes in 275 B.C.E. in Alexandria, Egypt.

    • Every human briefly exists as a single cell (after fertilization).

Anatomical and Directional Terms

  • Definition of Anatomy: Anatomy is concerned with the structure of body parts and their relationship with others.

  • Anatomical Position: Standing erect, facing forward, arms at sides, palms and toes directed forward.

Directional Terms

  1. Anterior: 前 (front)

  2. Posterior: 後 (back)

  3. Superior: 上 (above)

  4. Inferior: 下 (below)

  5. Medial: 內側 (toward the midline)

  6. Lateral: 外側 (away from the midline)

  7. Proximal: 近端 (closer to the origin)

  8. Distal: 遠端 (farther from the origin)

  9. Superficial: 表淺 (toward the surface)

  10. Deep: 深 (away from the surface)

  11. Ipsilateral: 同側 (on the same side)

  12. Contralateral: 對側 (on the opposite side)

Body Structures and Their Relationships

  • Relationships using directional terms

    • The frontal plane is ____ to the chin.

    • The chest is _ to the pelvic region.

    • The palm is _ to the arm.

    • The foot is _ to the femoral region.

  • Additional Examples:

    • The skin is ____ to the ribs.

    • The diaphragm is ____ to the lung.

    • The trachea is ____ to the lung (中下呼吸道).

Lower Respiratory Tract Structures

  1. Trachea (氣管): Passage of air to bronchi.

  2. Bronchus (支氣管): Passage of air to lungs.

  3. Bronchioles (細支氣管): Passage of air to alveoli.

  4. Lung (ii): Contains alveoli; responsible for gas exchange.

  5. Diaphragm (橫隔膜): Skeletal muscle; functions in ventilation.

Body Cavities

  • During embryonic development, the body divides into:

    • Dorsal (Posterior) Body Cavity

    • Ventral (Anterior) Body Cavity

  • Each major cavity is subdivided into smaller cavities.

  • All body cavities are lined with membranes, and the organs (viscera) within these cavities are covered by membranes.

Major Body Cavities

  1. Thoracic Cavity (胸腔)

    • Partitioned by the diaphragm from the abdominal cavity.

    • Contains pleural and pericardial cavities, as well as the mediastinum.

    • Contents:

      • Heart, lungs, esophagus.

  2. Abdominopelvic Cavity (腹腔及骨盆腔)

    • Divided into abdominal and pelvic cavities.

    • Abdominal Cavity: Contains digestive organs.

    • Pelvic Cavity: Contains reproductive and other organs.

Membranes Associated with Body Cavities

  1. Parietal Membrane: Lines the walls of body cavities.

  2. Visceral Membrane: Covers the organs.

  3. Specific Membranes:

    • Parietal pleura, parietal pericardium, parietal peritoneum.

Body Membranes

  • Definition: Thin sheets of tissue covering body surfaces, lining cavities, and covering hollow organs.

  • Subcategories:

    1. Mucous Membranes (黏膜)

    2. Serous Membranes (漿膜)

    3. Synovial Membranes (滑液膜)

    4. Cutaneous Membranes (皮膚)

Serous Membrane

  • Covers walls and organs in thoracic and abdominopelvic cavities.

  • Parietal Layer: Lines cavity walls.

  • Visceral Layer: Covers organs.

  • Serous Fluid: Reduces friction between internal organs.

Meninges (腦膜)

  • Lining for the posterior body cavity, protecting the brain and spinal cord.

  • Three Layers:

    1. Pia Mater (軟腦膜): Delicate inner layer.

    2. Arachnoid (蛛網膜): Fluid-filled web-like structure.

    3. Dura Mater (硬腦膜): Tough outer layer.

Summary of Body Cavities and Their Contents

  • Posterior Body Cavity:

    • Cranial Cavity: Contains the brain; lined by meninges.

    • Vertebral Canal: Contains the spinal cord; lined by meninges.

  • Anterior Body Cavity:

    • Thoracic Cavity:

    • Contents: Lungs, heart, respectively the pleural and pericardial cavities.

    • Membranes: Parietal and visceral pleura and pericardium.

    • Abdominopelvic Cavity:

    • Abdominal Cavity: Contents include stomach, intestines, liver.

    • Pelvic Cavity: Contains reproductive organs, urinary bladder, and rectum.

    • Membranes: Parietal and visceral peritoneum.

Introduction to Body Tissues

  • Definition of Tissues: Groups of similar cells performing a specific function.

  • Four Main Types:

    1. Epithelial Tissue (上皮組織): Covers and lines surfaces.

    2. Connective Tissue (結締組織): Supports and binds body parts.

    3. Muscular Tissue (肌肉組織): Contracts to enable movement.

    4. Nervous Tissue (神經組織): Transmits signals and responds to stimuli.

Functionality of Tissues

  • 4Cs:

    • Cover (Epithelial)

    • Connect (Connective)

    • Contract (Muscular)

    • Communicate (Nervous)

  • Example: The heart has epithelial covering, connective tissue valves, cardiac muscles that pump blood, and nerves that regulate heartbeat.

Epithelial Tissue

  • Characteristics:

    • Composed of tightly packed cells with minimal interstitial space.

    • Capable of rapid division to replace damaged or lost cells (e.g., skin cells).

    • Avascular: Lacks blood vessels; relies on underlying connective tissues for nutrients.

Functions of Epithelial Tissue

  • Protection: From drying, injury, and invasion (external surfaces).

  • Absorption: E.g., in the digestive tract via microvilli.

  • Secretion: E.g., in respiratory tract with mucus secretion.

  • Special Features: Ciliated cells sweep impurities away.

Classification of Epithelial Tissues

  • Simple Epithelium: One cell layer.

  • Stratified Epithelium: Two or more layers.

  • Types Based on Cell Shape:

    • Cuboidal: Cube-shaped cells.

    • Columnar: Tall, elongated cells.

    • Squamous: Flattened cells.

Specific Types of Epithelial Tissue

  1. Simple Squamous Epithelium: One layer of flat cells; facilitates diffusion (e.g., in alveoli of lungs).

  2. Stratified Squamous Epithelium: Multiple layers for protection;

    • Non-Keratinized: Protects moist surfaces (e.g., mouth, vagina).

    • Keratinized: Found in skin; cells accumulate keratin and die as they reach the surface.

Overview of Epithelial Tissues with Locations

Type

Description

Location

Simple Squamous

One layer of flattened cells

Blood capillaries; air sacs (alveoli) of lungs

Stratified Squamous

Many layers, flattened surface

Skin; entrances to structures opening outside

Simple Cuboidal

One layer of cube-shaped cells

Secreting glands; linings of kidney tubules

Stratified Cuboidal

Two or more layers of cube-shaped cells

Salivary gland and mammary gland ducts

Simple Columnar

One layer of elongated cells

Lining of digestive organs; uterine tubes

Stratified Columnar

Two or more layers of elongated cells

Pharynx; male urethra

Pseudostratified Columnar

Appears stratified, actually one layer

Air passages of the respiratory system

Transitional

Many layers, stretches

Urinary bladder and ureters

Connective Tissue Proper

  • General Function: Connects and supports structures throughout the body.

  • Types of Connective Tissue:

    • Loose Connective Tissue: Includes areolar tissue, adipose tissue, reticular tissue.

    • Dense Connective Tissue: Includes dense regular, dense irregular, and elastic connective tissue.

Loose Connective Tissue

  1. Areolar Connective Tissue:

    • Structure: Fewer cells and fibers; matrix with a jellylike substance.

    • Function: Binds tissues and organs together.

    • Cells: Fibroblasts produce extracellular fibers.

  2. Adipose Tissue:

    • Characteristics: Enlarged fibroblasts filled with fat; limited matrix.

    • Function: Energy storage, insulation, and cushioning for organs.

    • Appearance: Irregular honeycomb shape with pushed aside nuclei.

  3. Reticular Connective Tissue:

    • Cells: Reticular cells and scattered white blood cells.

    • Role: Forms a supportive network in lymphatic tissues (e.g., lymph nodes, spleen).

Dense Connective Tissue

  1. Dense Regular Connective Tissue:

    • Structure: Parallel bundles of protein fibers mainly collagen; strong to resist tension.

    • Location: Tendons (attach muscles to bones), ligaments (connect bones at joints).

  2. Dense Irregular Connective Tissue:

    • Structure: Fiber bundles arranged irregularly; offers strength in multiple directions.

    • Location: Dermis of the skin and joint capsules.

  3. Elastic Connective Tissue:

    • Function: Composed of elastic fibers enabling stretch and recoil.

    • Location: Found in large arteries and vocal cords.

Muscular Tissue

  • General Function: Comprised of muscle fibers capable of contraction.

  • Three Types of Muscle Tissue:

    1. Skeletal Muscle:

      • Voluntary, striated muscle attached to bones.

      • Function: Movement of limbs and other body parts.

    2. Smooth Muscle:

      • Involuntary muscle found in walls of hollow organs.

      • Characteristics: Contracts rhythmically; influenced by the nervous and endocrine systems (e.g., intestinal movement).

    3. Cardiac Muscle:

      • Found only in the heart; striated and involuntary.

      • Features: Strong contractions; regulated intrinsically and influenced by hormones and the nervous system.

Reference

  • Longenbaker, S.N. (2019). Mader's Understanding Human Anatomy & Physiology. (10th ed.). New York: McGraw-Hill.