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Chapter 1: An Introduction to Anatomy and Physiology - Vocabulary

Patterns Underlying the Diversity of Life

  • Biology is the study of life

  • One aim is to discover patterns underlying the diversity among various living organisms

  • All living things share common functions

Common Functions of All Living Things

  • Responsiveness

  • Growth

  • Reproduction

  • Movement

  • Metabolism

Responsiveness

  • Responsiveness (irritability): the ability to respond to a change in the immediate environment

  • Example: moving away from a painful stimulus (hand withdrawn from a hot stove)

  • Adaptability: capacity to make longer-term adjustments (e.g., growing a heavier coat of fur in winter)

Growth

  • Growth: increase in size of the organism

  • Achieved by: growth of cells or addition of new cells

  • Complex organisms primarily grow by increasing cell number

  • Cellular differentiation: process of cells becoming specialized for particular functions

Reproduction and Movement

  • Reproduction: creation of new generations of the same type of organisms

  • Movement: internal (transporting blood, food, or materials within the body) or external (moving through the environment)

Metabolism

  • Metabolism: sum of all chemical operations in the body

  • Chemical reactions provide energy for responsiveness, growth, reproduction, movement

  • Cells use materials absorbed from environment for energy: nutrients from food and oxygen

  • More complex organisms require specialized structures and systems for metabolic processes

Metabolic Processes

  • Respiration: absorption, transport, and use of oxygen by cells

  • Digestion: breaking down complex foods into simpler absorbable compounds

  • Excretion: elimination of waste products from metabolic operations

Checkpoint (1 of 8)

  • How do vital functions such as responsiveness, growth, reproduction, and movement depend on metabolism?

Anatomy vs Physiology; Relationship

  • Anatomy: study of internal and external structure and physical relationships between body parts

  • Physiology: study of function in living organisms

  • Interrelation: anatomy gives clues about likely function; physiology is explained in terms of anatomy

Levels of Organization (1 of 4)

  • Chemical level

    • Atoms are the smallest stable units of matter

    • Atoms combine to form molecules

    • Molecular shape determines function

  • Cellular level

    • Made up of cells, the smallest living units in the body

    • Molecules interact to form larger structures with functions in cells

Levels of Organization (2 of 4)

  • Tissue level

    • A tissue is composed of similar cells working together to perform a specific function

  • Organ level

    • An organ is composed of two or more different tissues working together to perform specific functions

Levels of Organization (3 of 4)

  • Organ system level

    • An organ system consists of organs interacting to perform specific functions

  • Organism level (4 of 4)

    • An organism consists of all organ systems working together to maintain life and health

    • This is the highest level of organization

Figure Reference

  • Figure 1-1: Levels of organization (conceptual mapping across levels)

  • Note: The next figures show how organ systems integrate to sustain life

The 11 Organ Systems of the Human Body (1 of 7)

  • Integumentary

  • Skeletal

  • Muscular

  • Nervous

  • Endocrine

  • Cardiovascular

  • Lymphatic

  • Respiratory

  • Digestive

  • Urinary

  • Reproductive

The 11 Organ Systems of the Human Body (2 of 7)– (Figure 1-2)

  • Visual overview of how organ systems relate to each other

The 11 Organ Systems of the Human Body (3–7 of 7)– (Figures 1-2)

  • Visual references showing interconnections among the 11 systems

Checkpoint (4 of 8)

  • Identify the organ systems of the body and list their major functions

  • Which organ system includes the pituitary gland and directs long–term changes in the activities of the body’s other systems?

Homeostasis

  • Homeostasis: a state of internal balance or a stable internal environment

  • Must be maintained to survive; malfunction of organ systems when homeostatic responses are overwhelmed can lead to illness or disease

  • Accomplished by interdependent cells, tissues, organs, and organ systems functioning together

Homeostatic Regulation

  • Adjustments in physiological systems that preserve homeostasis

  • Typically involves:

    • A receptor: senses a change or stimulus

    • A control center (integration center): receives/processes information from the receptor

    • An effector: responds to commands from the control center

  • Response may oppose or enhance the original stimulus

Example: Homeostasis Outside the Body (Thermostat Analogy)

  • Thermostat: control center

  • Receptor: thermometer detects changes from the set point

  • Effector: heater or air conditioner

  • Response: opposes or negates the original stimulus

  • Negative feedback example: Restores room temperature to set point (37.2°C body temperature analog used in slides)

Checkpoint (5 of 8)

  • Define homeostasis

  • Why is homeostatic regulation important to an organism?

  • What happens to the body when homeostasis breaks down?

Negative Feedback (1 of 2)

  • More common form of homeostatic regulation

  • Variations from normal trigger automatic responses

  • Response corrects situation back to normal range

  • Example: thermoregulation

    • If body temperature is too high: responses that lower temperature

    • If body temperature is too low: responses that raise temperature

Negative Feedback: Thermoregulation (1 of 2)

  • High body temperature triggers:

    • Sweat glands increase secretion; evaporation cools the body

    • Smooth muscle in skin vessels dilates; increased blood flow to surface

  • Result: temperature is reduced to normal range

Negative Feedback: Thermoregulation (2 of 2)

  • Low body temperature triggers:

    • Sweat gland activity decreases

    • Blood vessels constrict; reduced heat loss to environment

    • Skeletal muscles contract (shivering) to generate heat

  • Result: temperature increases to normal range

Figure: Negative Feedback—Control of Body Temperature (Figure 1-4)

  • Conceptual flow: Stimulus -> Receptors -> Control Center -> Effectors -> Response -> Homeostasis restored

Checkpoint (6 of 8)

  • Explain the function of negative feedback systems

  • Why is positive feedback helpful in blood clotting but unsuitable for the regulation of body temperature, as with a fever?

Positive Feedback (1 of 2)

  • Response reinforces or exaggerates the original stimulus

  • Escalating cycle or positive feedback loop

  • Used in dangerous or stressful processes that require rapid completion

  • Examples: blood clotting in response to blood loss; labor and delivery during childbirth

Positive Feedback (2 of 2)

  • Typically less common for maintaining homeostasis; aids in urgent processes

Checkout: Anatomical Terminology

  • Common language required for clear communication: medical terminology

  • Terms are often based on Latin or Greek roots

  • Descriptions cover body regions, anatomical positions, directions, and body sections

Anatomical Landmarks (1 of 2)

  • Anatomical position:

    • Hands at the sides, palms facing forward, feet together

  • Supine: lying face up

  • Prone: lying face down

Anatomical Landmarks (2 of 2)

  • Figure 1-6: Anatomical landmarks (visual reference)

Anatomical Regions

  • Surface of the abdomen and pelvis can be mapped using two methods:

    • Abdominopelvic quadrants (4): used by clinicians to locate aches, pains, injuries

    • Abdominopelvic regions (9): used by anatomists for more precise internal location

Abdominopelvic Quadrants and Regions (1 of 3)

  • Figure 1-7a: Abdominopelvic quadrants

Abdominopelvic Quadrants and Regions (2 of 3)

  • Figure 1-7b: Abdominopelvic regions

Abdominopelvic Quadrants and Regions (3 of 3)

  • Figure 1-7c: Abdominopelvic relationships

Anatomical Directions (1 of 2)

  • Directional terms relate structures to the anatomical position

  • Some terms are interchangeable: anterior vs ventral; posterior vs dorsal

  • Left and right refer to the subject's left and right, not the observer’s

Anatomical Directions (2 of 2)

  • Figure 1-8: Directional references

  • Key terms with examples:

    • Superior (cranial/cephalic): toward the head; e.g., the head is superior to the knee

    • Inferior (caudal): toward the feet; below

    • Anterior (ventral): toward the front

    • Posterior (dorsal): toward the back

    • Proximal: nearer to an attached base

    • Distal: farther from an attached base

    • Medial: toward the midline; Lateral: away from the midline

    • Superficial: nearer the surface; Deep: farther from the surface

Sectional Anatomy

  • Sectional anatomy allows better understanding of 3D aspects of the human body

  • Essential for interpreting imaging techniques that provide internal views

  • Described relative to three primary sectional planes

Sectional Planes (1 of 2)

  • Frontal plane (coronal plane): divides body into anterior and posterior portions; frontal (coronal) section

  • Sagittal plane: divides body into left and right portions; midsagittal section divides into equal right and left halves

  • Transverse plane: divides body into superior and inferior portions; transverse (cross) section

Sectional Planes (2 of 2)

  • Figure 1-9: Sectional planes (visual references)

Checkpoint (7 of 8)

  • What is the purpose of anatomical terms?

  • Describe an anterior view and a posterior view in the anatomical position

  • What type of section would separate the two eyes?

Body Cavities of the Trunk (1 of 2)

  • True body cavities: closed, fluid-filled spaces lined by serous membranes

  • Internal organs (viscera) are suspended within the cavities

  • Functions: protect organs from shocks; allow organs to change shape/size

Body Cavities of the Trunk (2 of 2)

  • Two major regions: Thoracic cavity and Abdominopelvic cavity

  • These regions are separated by the diaphragm (flat muscular sheet)

Serous Membranes

  • Produce watery serous fluid that moistens opposing surfaces and reduces friction

  • Parietal layer lines the inner surface of the body wall/chamber

  • Visceral layer covers the surfaces of visceral organs

  • When visceral and parietal layers are in direct contact, the cavity is a potential space

Thoracic Cavity

  • Contains three internal chambers:

    • One pericardial cavity (contains the heart)

    • Two pleural cavities (one for each lung)

  • Each cavity is lined by a serous membrane

Pericardial Cavity

  • Heart projects into the pericardial cavity

  • Lined by serous membrane called the pericardium:

    • Visceral pericardium covers the heart

    • Parietal pericardium lines the outer layer

  • Pericardial fluid between layers reduces friction

  • Lies within the mediastinum

Pleural Cavities

  • Each lung resides in its own pleural cavity

  • Lined by serous membrane called the pleura:

    • Visceral pleura covers the lung surface

    • Parietal pleura lines the mediastinum and inner body wall

Abdominopelvic Cavity

  • Extends from the diaphragm to the pelvis

  • Subdivided into abdominal cavity (superior) and pelvic cavity (inferior)

  • Contains the peritoneal cavity

Peritoneal Cavity

  • Lined by serous membrane called peritoneum:

    • Visceral peritoneum covers enclosed organs

    • Parietal peritoneum lines the inner surface of the body wall

  • Some organs lie between peritoneal lining and the dorsal wall of the abdominal cavity; this position is called retroperitoneal

Figure Reference

  • Figure 1-10: Subdivisions of the Body Cavities of the Trunk

Checkpoint (8 of 8)

  • Describe two essential functions of body cavities

  • Describe the various body cavities of the trunk

  • If a surgeon makes an incision just inferior to the diaphragm, what body cavity will be opened?

Quick Connections and Practical Implications

  • Understanding the organization of the body helps in clinical reasoning, imaging interpretation, and surgical planning

  • Homeostatic principles underpin many clinical interventions (e.g., fever management, cooling/heating strategies, hormonal regulation)

  • Knowledge of anatomical terminology and directional references is essential for clear communication in healthcare

  • Recognizing body cavities and serous membranes is critical for understanding disease processes (e.g., effusions, inflammation, and compartment syndromes)

Key Terms to Remember (quick glossary)

  • Homeostasis, Homeostatic Regulation, Receptor, Control Center, Effector, Negative Feedback, Positive Feedback

  • Anatomical Position, Supine, Prone

  • Superior, Inferior, Anterior, Posterior, Medial, Lateral, Proximal, Distal, Superficial, Deep

  • Frontal/Coronal Plane, Sagittal Plane, Midsagittal Plane, Transverse Plane

  • Thoracic Cavity, Abdominopelvic Cavity, Pericardial Cavity, Pleural Cavities, Peritoneal Cavity, Retroperitoneal

  • Parietal vs Visceral Serous Membranes, Serous Fluid

  • 11 Organ Systems: Integumentary, Skeletal, Muscular, Nervous, Endocrine, Cardiovascular, Lymphatic, Respiratory, Digestive, Urinary, Reproductive

  • Levels of Organization: Chemical, Cellular, Tissue, Organ, Organ System, Organism

  • Abdominopelvic Quadrants (4) and Regions (9)

11 Organ Systems overview: all listed above
1.1–1.8 Learning Outcomes: describe and explain core concepts as outlined in Chapter 1