Introduction to the Human Body - BIOL 2457 Anatomy & Physiology I

Anatomy vs. Physiology

  • Anatomy is the study of the structures of the body and their relationships to each other.
    • Anatomy is what's there.
    • It is the oldest medical science.
  • Physiology is the study of the functions of the body parts and how they work to carry out their life-sustaining activities.
    • Physiology is what it does.
  • Anatomy dictates physiology AND physiology dictates anatomy.

Examples: Teeth

  • Incisors
    • Anatomy: (example description of incisor anatomy)
    • Physiology: (example description of incisor physiology)
    • How anatomy dictates physiology: (explanation of how the incisor's structure supports its function)
  • Molars
    • Anatomy: (example description of molar anatomy)
    • Physiology: (example description of molar physiology)
    • How anatomy dictates physiology: (explanation of how the molar's structure supports its function)

Types of Anatomy

  • Gross Anatomy
    • Studying anatomy without a microscope
  • Microscopic Anatomy
    • Studying anatomy with a microscope

Types of Physiology

  • Molecular Physiology
    • Studying the function of individual molecules
  • Cellular Physiology
    • Studying the function of individual cells
  • Systemic Physiology
    • Studying the function of individual organ systems
  • Pathophysiology
    • Studying how diseases & aging alter physiology

Structural Organization

  • Atoms
  • Molecules
  • Organelle
  • Cellular Level
    • Cells are made up of molecules.
  • Tissue Level
    • Tissues consist of cells that are similar in structure and function.
  • Organ Level
    • Organs are made up of different types of tissues.
  • Organ System Level
    • Organ systems consist of different organs that work together closely.
  • Organismal Level
    • The human organism is made up of many organ systems.

Functions for Life

  • Separation of internal & external environments is necessary.
    • The plasma membrane separates cells from each other & from their environment.
    • The skin separates the body’s internal environment from the external environment.
  • Movement is necessary.
    • Motility is when substances move through the body (cardiac muscle & smooth muscle do this).
    • Locomotion is when whole body parts move (skeletal muscles do this).
  • Living things respond to stimuli.
    • Stimuli are changes in the internal or external environment.
    • Once they are detected, reactions occur to address them.
  • Digestion & absorption are necessary.
    • Digestion is breaking down ingested substances.
    • Once large molecules are broken down, small molecules can be absorbed.
  • Metabolism is necessary.
    • Metabolism is the sum of all the chemical reactions that keep an organism alive.
    • Catabolism: the reactions that break down large molecules.
    • Anabolism: the reactions to build large molecules.
  • Excretion is necessary.
    • Waste products (like feces, urea, & carbon dioxide) must leave the body.
  • Growth & repair are necessary.
    • Growth is an increase in the size or number of cells.
    • For repair of tissues to occur, cells must divide & be metabolically active.
  • Reproduction is necessary*
    • Reproduction is the production of offspring.
    • *it is NOT vital to individual organisms to reproduce.
    • *it IS vital for species to reproduce.
  • Homeostasis
    • Maintenance of stable internal conditions.
    • The central principle of physiology.

Homeostasis

  • Definition: a relatively constant set of internal conditions that stay the same even when external conditions change.
    • Homeostasis is dynamic, meaning it changes to keep things in balance.
    • All the body’s organ systems work together to maintain homeostasis.
  • Homeostasis is maintained using negative & positive feedback loops.

Negative Feedback Loops

  • This is the most common kind of feedback loop
  • Goal: to get the body back to the original set point as quickly as possible
    • The response reduces (or completely cancels) the impact of the stimulus on the body
  • Examples
    • Thermoregulation (e.g., body temperature)
    • Chemical balance (e.g., pH or blood salinity)
    • Hormone levels (e.g., insulin & glucagon – regulate blood sugar levels)

Positive Feedback Loops

  • Goal: to create a “new (temporary) set point”
  • The response increases the effect of the stimulus
  • Positive feedback loops control things that are NOT constantly being adjusted
  • Examples
    • Blood clotting
    • Labor & delivery
    • Neuron signaling

Organ Systems Interact

  • Complex functions in the body require multiple organ systems in the body to working together properly
  • Example: respiration
  • All levels of organization are interdependent

The 11 Organ Systems

  • Organ systems are made of groups of organs that work together to accomplish complex functions

Organ System Functions and Names

  • 1) Integumentary: The external body covering that makes Vitamin D and has receptors & glands
  • 2) Muscular: The system that enables movement, maintains posture, and generates heat
  • 3) Skeletal: The system that protects & supports organs and provides a framework for muscle attachment
  • 4) Nervous: The control system that responds to internal & external stimuli
  • 5) Cardiovascular: The system that pumps blood (with oxygen, carbon dioxide, nutrients, & waste)
  • 6) Lymphatic: The system that collects fluid that leaks out of blood vessels and houses white blood cells
  • 7) Respiratory: The system that supplies oxygen to the blood and removes carbon dioxide
  • 8) Endocrine: The glands that secrete hormones to regulate growth, reproduction, & metabolism
  • 9) Digestive: The system that breaks down food into absorbable units (that enter the bloodstream) & eliminates waste
  • 10) Urinary: The system that regulates water, electrolyte, and acid-base balance in the blood
  • 11) Reproductive: The system that is used to generate offspring

Body Cavities

  • All of the body’s organs are found inside cavities
    • Cavities provide protection to the organs inside of them
  • Cavities can be closed or open
    • Closed cavities are seen on the image
    • Open cavities include:
      • The oral cavity
      • The digestive cavity
      • The nasal cavity
      • The orbital cavity
      • The external ear

Dorsal cavities: cranial & vertebral

  • Protect brain and spine or vertebral column

Ventral cavities: thoracic, abdominal, & pelvic

  • The ventral cavities protect the visceral organs

Body Cavity Practice

  • A patient having a heart attack: Thoracic cavity
  • A patient having a stroke: Cranial cavity
  • A patient with a urinary tract infection: Pelvic cavity
  • Pain in the pleural cavity
  • Pain in the abdominopelvic cavity

Abdominopelvic Quadrants

  • Quadrants are used primarily by medical personnel
  • Major RUQ organs:
    • Liver, Gallbladder
  • Major RLQ organs:
    • Large + Small Intestine, Appendix
  • Major LUQ organs:
    • Pancreas, Stomach
  • Major LLQ organs:

Regional Terms

  • Axial: head, neck trunk
  • Appendicular: limbs

Directional Terms

  • Directional terms help to describe the location of body structures compared to one another
    • Directional terms come in pairs
  • Directional terms are based on the body in anatomical position
    • The body is erect
    • The palms are facing forward
    • The feet are slightly separated

Directional Terms

  • Left vs. right

    • Put yourself in the patient’s shoes!

  • Lateral vs. medial

    • Location relative to the midline of the body
      • Lateral: farther from the midline
      • Medial: closer to the midline

  • Superior vs. inferior

    • Superior: above
    • Inferior: below

  • Proximal vs. distal

    • These are your only options with 2 things on an arm / leg!
      • Proximal: closer to the attachment point
      • Distal: farther from the attachment point

  • Anterior vs. posterior

    • Anterior: closer to the front
    • Posterior: closer to the back

  • Ventral vs. Dorsal

    • Ventral: closer to the front
    • Dorsal: closer to the back

  • Superior vs. inferior

    • Superior: above
    • Inferior: below

  • Proximal vs. distal

    • These are your only options with 2 things on an arm / leg!
      • Proximal: closer to the attachment point
      • Distal: farther from the attachment point

Directional Terms Practice

  • The sternum is superior to the pelvis.
  • The sternum is Ventral to the vertebrae.
  • The sternum is Medial to the humerus.
  • The humerus is proximal to the radius.

Body Planes

  • Planes are used to section part(s) of the body for better visualization
    • Midsagittal Section: Left & right sections are created
    • Frontal Section: Anterior & posterior sections are created
    • Transverse Section: Superior & inferior sections are created

Parasagittal Plane

  • Sagittal planes that are uneven (not down the midline) are called parasagittal planes.

Midsagittal Plane

  • If the sagittal plane runs directly down the midline of the body, it is called a "midsagittal plane" or median plane.

Frontal (or Coronal) Plane

  • The frontal (or coronal) plane will literally leave you with a "front" and back portion.
  • a plane that runs vertically from top to bottom, and it divides the body in to a front (anterior) side and a back (posterior) side.

Transverse (or Horizontal) Plane

  • This is the only horizontal plane, and it divides the body into a top (superior) and bottom (inferior) portion.

Oblique Planes

  • a plane that is any type of angle other than horizontal or vertical angle.
  • "oblique" means that something is not parallel or a right angle. An easy way to remember this is to remember "obliques are odd angles."