Introduction to Human Anatomy & Physiology (ASU - Traylor)

Introduction to Human Anatomy and Physiology

  • Authors/Source: Arizona State University, Daryl O. Traylor (dtraylor@asu.edu)
  • Focus: Foundational concepts in anatomy and physiology, homeostasis, body organization, organ systems, planes, cavities, membranes, and regional anatomy.

Introduction: Definitions of Anatomy and Physiology

  • Anatomy: the scientific study of the body’s structures and how they relate to each other.
  • Physiology: the scientific study of the chemistry and physics of the structures of the body and the ways in which they work together to support the functions of life.
  • Relationship: Anatomy and Physiology are complementary; understanding one aids understanding the other.
  • Easy Concept: These definitions provide a framework for studying how the body is organized and how it functions.

Principle of Complementarity

  • Core idea: Anatomy and Physiology go together to explain how the body works; you need physiology to understand how a structure is designed, and anatomy to understand how it functions.
  • Examples illustrating complementarity:
    • Why the heart and lungs sit beside each other: functional integration of gas exchange and circulation.
    • Why humans can grab objects while ducks cannot: structural design supports specific functions; physiological demands explain how those structures work.
  • Emphasis: The two disciplines are interdependent in explaining bodily function.

Levels of Structural Organization of the Human Body

  • Concept: The organization of the body is often discussed in terms of levels of increasing complexity.
  • Text note: There are six distinct levels of increasing complexity (as described in the slides), with a chain that lists multiple finer components.
  • Chain as presented:
    AtomsoMoleculesoOrganellesoCellsoTissuesoOrgansoOrgansystemsoOrganismAtoms o Molecules o Organelles o Cells o Tissues o Organs o Organ systems o Organism
  • Note: The list shows eight items, while the text mentions six distinct levels; the sequence includes atoms up to organism, capturing the full hierarchical view.

The Organ Systems (Overview with Easy Concepts)

  • Integumentary System
    • Components: Hair, Skin, Nails
    • Functions: Encloses internal body structures; site of many sensory receptors.
  • Skeletal System
    • Components: Bones, Cartilage, Joints
    • Functions: Supports the body; enables movement (in conjunction with the muscular system).
  • Muscular System
    • Components: Skeletal muscles, Tendons
    • Functions: Enables movement (with the skeletal system); helps maintain body temperature.
  • Nervous System
    • Components: Brain, Spinal cord, Peripheral nerves
    • Functions: Detects and processes sensory information; activates bodily responses.
  • Endocrine System
    • Components: Pituitary gland, Thyroid gland, Pancreas, Adrenal glands, Tests, Ovaries
    • Functions: Secretes hormones; regulates bodily processes.
  • Cardiovascular System
    • Components: Heart, Blood vessels
    • Functions: Delivers oxygen and nutrients to tissues; helps regulate body temperature.
  • Lymphatic System
    • Components: Thymus, Lymph nodes, Spleen, Lymphatic vessels
    • Functions: Returns fluid to blood; Defends against pathogens.
  • Respiratory System
    • Components: Nasal passages, Trachea, Lungs
    • Functions: Removes carbon dioxide; Delivers oxygen to blood.
  • Digestive System
    • Components: Stomach, Liver, Gall bladder, Small intestine, Large intestine
    • Functions: Processes food for use by the body; removes wastes from undigested food.
  • Urinary System
    • Components: Kidneys, Urinary bladder
    • Functions: Controls water balance; Removes wastes from blood and excretes them.
  • Male Reproductive System
    • Components: Epididymis, Testes (glands support), …
    • Functions: Produces sex hormones and gametes; Delivers gametes to the female.
  • Female Reproductive System
    • Components: Ovaries, Mammary glands, Uterus
    • Functions: Produces sex hormones and gametes; Supports embryo/fetus until birth; Produces milk for infant.
  • Easy Concept: The organ systems cooperate to maintain homeostasis and enable life-sustaining functions.

Functional Requirement of Life

  • Maintenance of life involves several basic requirements:
    • Organization
    • Metabolism
    • Responsiveness
    • Movement
    • Development, Growth and Reproduction
  • Easy Concept: Metabolism includes both anabolic and catabolic processes.
  • Metabolism details:
    • Anabolic reactions build up materials and consume energy.
    • Catabolic reactions break materials down and release energy.
    • Overall metabolism is the sum of anabolic and catabolic reactions: extMetabolism=extAnabolism+extCatabolismext{Metabolism} = ext{Anabolism} + ext{Catabolism}

Organization and Metabolism in Depth

  • Organization: trillions of cells organized to maintain distinct internal compartments.
  • Metabolism: sum of all anabolic and catabolic reactions; both occur continuously to keep you alive.
  • Easy Concept: Reinforces that life depends on structured organization and ongoing chemical processes.

Homeostasis

  • Definition: A dynamic state of internal environment balance around a set point; the body continually re-corrects and readjusts as needed.
  • Set point: The physiological value around which the normal range fluctuates; each condition has a particular set point.
  • Normal range: The restricted range of values that is optimally healthful and stable (e.g., temperature, BP, hydration).

Regulation of Homeostasis

  • Homeostasis is a collaborative effort across all organ systems, especially the nervous and endocrine systems; other systems play major roles.
  • Maintenance mechanism: Active monitoring and regulation across the body.
  • Internal variables (set points) may change due to internal or external factors; stimuli cause changes in these variables.
  • Stimulus: A factor that causes changes in the variables (plural: stimuli).

Homeostatic Regulation: Three Components

  • Receptor
    • Monitors a physiological value; senses changes; initiates a response via a signal when changes occur.
  • Control Center
    • Determines the favorable set point; receives signals from receptors; decides if a response is needed, and how/where to respond.
  • Effector
    • Carries out the response as ordered by the control center; typically a muscle or a gland.

Negative Feedback

  • Principle: Reverses a deviation from the set point to maintain parameters within their normal range.
  • Operation: Continuous process throughout the body; aims to stop the stimulus effect or oppose it.
  • Examples used: body temperature, blood glucose, blood pressure, blood pH (involving various systems: nervous, endocrine, urinary, respiratory).
  • Key point: The control center for these processes can vary; not always the nervous system.

Negative Feedback in Action (Illustrative Examples)

  • Example loop for body temperature:
    • Stimulus: Body temperature rises above the set point (37°C).
    • Sensor: Nerve cells in skin and brain detect change.
    • Control: Temperature regulatory center in brain processes data.
    • Effector: Sweat glands throughout body promote cooling.
    • Result: Body temperature returns toward set point.
  • Other depicted examples include blood glucose and blood pressure regulation by respective systems.

Positive Feedback

  • Definition: Intensifies a change rather than reversing it; deviation from normal range leads to more change.
  • Normality: Positive feedback is normal only when there is a definite endpoint.
  • Examples:
    • Childbirth (labor contractions intensify until delivery).
    • Body’s response to blood loss (feedback loop accelerates processes to stop bleeding but ends at a defined outcome).
  • Key idea: Positive feedback amplifies a process until a goal is achieved, then ceases.

Homeostatic Imbalance

  • If homeostasis is disrupted and cannot be restored, severe consequences may result.
  • Examples: Diabetes and abnormal blood pressure can arise when the body cannot restore the set point.
  • Aging: The body's ability to restore homeostasis is reduced with age.

Anatomical Position, Planes, and Regions (Group 1) – Overview

  • Anatomical Position (Standard Reference)
  • Planes used to study internal organs, and how sections are named.
  • Abdominopelvic Quadrants
  • Abdominopelvic Regions
  • Serous membranes and fluid-filled spaces between layers
  • Group Discussion Questions 1/2 (to connect to practice questions)

Anatomical Position

  • Standard Anatomical Position:
    • Body standing upright
    • Feet shoulder-width apart and parallel
    • Palms and toes directed forward
  • Easy Concept

Directional Terms

  • Anterior (ventral): toward the front of the body; example: toes are anterior to the foot.
  • Posterior (dorsal): toward the back; example: popliteus is posterior to the patella.
  • Superior (cranial): higher than another part; example: orbits are superior to the oris.
  • Inferior (caudal): lower than another part; example: pelvis is inferior to the abdomen.
  • Lateral: toward the side; example: thumb is lateral to the digits.
  • Medial: toward the middle; example: hallux is medial to the other toes.

More Directional Terms

  • Proximal: nearer to the point of attachment or trunk (e.g., brachium proximal to antebrachium).
  • Distal: farther from the point of attachment or trunk (e.g., crus distal to the femur).
  • Superficial: closer to the surface; example: skin is superficial to bones.
  • Deep: farther from the surface; example: brain is deep to the skull.

Regional Terms

  • Purpose: Precise language for body regions to improve communication in health fields.
  • Anterior view list includes terms such as Frons/forehead, Oris/mouth, Mentis/chin, Axilla/armpit, Brachium/arm, Antebrachium/forearm, Carpus/wrist, Pollex/thumb, Palma/palm, Digits/fingers, Cranium/skull, Facies/face, Patella/kneecap, Crus/leg, Tarsus/ankle, Hallux/great toe, Oculus/eye, Buccal/cheek, Auris/ear, Nasus/nose, Cervicis/neck, Thorcis/chest, Mamma/breast, Abdomen, Umbilicus/navel, Hip/coxal, Pelvis/pelvic, Inguen/groin, Pubis, Femur/thigh, Pes/foot, Shoulder/acromial, Dorsum/back, Gluteus/buttock, Popliteus/back of knee, Sura/calf, Calcaneus/heel, Planta/sole.
  • Posterior view includes Cephalon/head, Cervicis/neck, Lower limb, Upper limb, and a list of related landmarks.
  • Easy Concept: these terms provide a standardized vocabulary for anatomical descriptions.

Body Planes and Sections

  • Planes: imaginary two-dimensional surfaces that pass through the body.
  • Three primary planes:
    • Sagittal plane
    • Frontal (coronal) plane
    • Transverse (horizontal) plane
  • Sections: two-dimensional surfaces produced by slicing a three-dimensional structure; named according to the plane of the cut.
  • Example: a sagittal plane cut yields a sagittal section.

Sagittal Plane Details

  • Divides the body/organ vertically into right and left parts.
  • Midsagittal (median) plane: equal left and right parts.
  • Parasagittal plane: unequal left and right parts.

Frontal (Coronal) Plane Details

  • Divides body/organ into anterior (front) and posterior (rear) portions.
  • Also called the coronal plane (Latin: corona = crown).

Transverse (Horizontal) Plane Details

  • Divides body/organ horizontally into upper and lower portions.
  • Produces cross sections.

Body Cavities and Serous Membranes

  • Purpose: maintain internal organization by separating compartments with membranes; cavities contain and protect delicate organs.

Dorsal and Ventral Body Cavities

  • Dorsal cavity: protection of parts of the nervous system; subcavities include Cranial and Vertebral.
  • Ventral cavity: holds the visceral organs (viscera); two sub-cavities separated by the diaphragm: Thoracic cavity and Abdominopelvic cavity.
  • Visual layout: cranial and vertebral on dorsal; thoracic and abdominopelvic on ventral.

Dorsal Cavity Details

  • Cranial cavity: holds brain.
  • Vertebral (spinal) cavity: holds spinal cord.

Ventral Cavity Details

  • Thoracic cavity: enclosed by the rib cage; includes pericardial cavity (within the mediastinum) around the heart and pleural cavities around the lungs; other organs located in the superior mediastinum.
  • Abdominopelvic cavity: largest cavity; no physical barrier; abdomen contains stomach, liver, spleen, intestines, part of pancreas; pelvic cavity contains urinary bladder, female reproductive organs, and rectum.

Serous Membranes (Serosa)

  • Characteristics: thin membranes covering walls and organs in thoracic and abdominopelvic cavities; double-layered with a fluid-filled space between.
  • Parietal serosa: attached to inner wall of the body cavity.
  • Visceral serosa: attached to the surface of organs.
  • Function: reduce friction between organs and cavity walls by fluid in the serous space.

Serous Membrane Compartments

  • Three serous cavities and their membranes:
    • Pericardium surrounds the heart in the pericardial cavity.
    • Pleurae surround the lungs in the pleural cavities.
    • Peritoneum surrounds various organs in the abdominopelvic cavity.

Abdominal Regions and Quadrants

  • Quadrants: there are four abdominal quadrants used for localization:
    • Left upper quadrant (LUQ)
    • Right upper quadrant (RUQ)
    • Right lower quadrant (RLQ)
    • Left lower quadrant (LLQ)
    • Easy Concept
  • Regions: there are nine abdominal regions used for more precise localization:
    • Right hypochondriac, Epigastric, Left hypochondriac
    • Right lumbar, Umbilical, Left lumbar
    • Right Iliac (inguinal), Hypogastric, Left iliac (inguinal)
  • Easy Concept: Abdominopelvic regions provide a standardized map for clinical assessment.

Group Discussion Questions (2/2 Topics)

  • 1) What is the anatomical position?
  • 2) List the planes used to study the internal organs of the human body.
  • 3) List the abdominopelvic quadrants.
  • 4) List the abdominopelvic regions.
  • 5) Explain the structure of serous membranes including the fluids between the layers.
  • Note: This section complements Group Discussion Questions 1/2.

Quick Reference: Anatomic Terminology Summary

  • Anatomical Position: standard reference posture for describing body terms.
  • Planes: sagittal, frontal/coronal, transverse.
  • Regions and Quadrants: nine regions and four quadrants for abdominal mapping.
  • Serous Membranes: parietal vs visceral layers with fluid-filled cavity in between to minimize friction.
  • Body Cavities: dorsal vs ventral; subcavities within each.
  • Organ System Functions: summarized in the organ systems section above.
  • Homeostasis and Regulation: overview of feedback mechanisms and stability in the body.

Group Discussion Questions (1/2 Topics) – Highlights

  • What does anatomy and physiology mean? Reiterate complementarity principle.
  • What are the organ systems in the human body and their major functions?
  • Define homeostasis. Identify the three parts involved in maintaining homeostasis and describe the function of each.