Major Themes of Anatomy and Physiology
Course Logistics and Policies
Quiz / Exam Dates:
Students are responsible for knowing exam dates and covered chapters.
Instructors will not answer emails or texts asking for this information.
The syllabus contains all necessary information regarding chapters, days off, and policies.
Missing an Exam:
A documented reason is required for missing an exam (e.g., doctor's note, tow truck receipt).
Simply stating "I don't feel well" is not sufficient.
Study Tips (from a student's perspective):
Print out slides before class as they are "fair game."
Study each slide thoroughly.
Develop personal methods to remember names and locations of structures.
Study in silence to avoid distractions.
Study briefly every day.
In the days leading up to a quiz or exam, cover one lecture in depth per day until all are reviewed.
The day before the test, briefly review all relevant lectures and quiz oneself using printed notes, covering labeled parts, saying their names aloud, and spelling them.
Academic Dishonesty:
Cheating is strongly condemned.
Consequences range from a zero on the assignment to failure of the course, or even a recommendation for suspension/expulsion from the university, depending on severity.
Introduction to Anatomy and Physiology
Anatomy: The study of structure.
Physiology: The study of function.
Complementary Relationship: Anatomy and physiology are inseparable. Physiology gives meaning to anatomy, and anatomy makes physiology possible.
Anatomy: The Study of Form
Methods to Examine the Human Body's Structure:
Inspection: Looking at the body's appearance.
Palpation: Feeling structures with the hands.
Auscultation: Listening to sounds produced by the body.
Percussion: Tapping on the body, feeling for resistance, and listening to emitted sounds for abnormalities.
Dissection: Cutting and separating human body tissues to reveal their relationships, often using a cadaver (a dead human body).
Comparative Anatomy: Studying (e.g., dissecting) multiple species to understand form, function, and evolution.
Exploratory Surgery: Opening the living body to diagnose problems; largely replaced by medical imaging.
Radiology: The branch of medicine specializing in medical imaging.
The Greek and Roman Legacy in Medicine
Hippocrates (Greek Physician):
Considered the "Father of Medicine."
Established a code of ethics (Hippocratic Oath).
Advocated seeking natural causes for diseases rather than attributing them to gods or demons.
Aristotle:
Believed diseases had supernatural causes (called theologi) or physical causes (called physiologi).
The terms "physician" and "physiology" originated from his work.
Believed complex structures are built from simpler parts.
Metrodora (Greek Physician):
The first woman to publish a medical textbook.
Claudius Galen (Physician to Roman gladiators):
Performed animal dissections due to the ban on human cadavers.
Viewed science as a method of discovery.
His teachings were widely adopted as dogma in Europe during the Middle Ages.
The Birth of Modern Medicine
Andreas Vesalius (Beginning of modern Western medicine):
Challenged traditional beliefs after the Catholic Church relaxed restrictions on cadaver dissection.
Performed his own dissections, unlike his predecessors who relied on barber-surgeons.
Published the first comprehensive atlas of anatomy, De Humani Corporis Fabrica (On the Structure of the Human Body), in 1543.
William Harvey (Early Physiologist):
His contributions marked the birth of experimental physiology.
Published De Motu Cordis (On the Motion of the Heart) in 1628.
Realized that blood flows out from the heart and returns to it.
Credit for this understanding is also given to Michael Servetus.
Robert Hooke (Microscopist):
Greatly improved the compound microscope, inventing the specimen stage, illuminator, and coarse/fine focus controls.
His microscopes magnified up to 30X.
First to observe and name "cells."
Published Micrographia, the first comprehensive book on microscopy, in 1665.
Antony van Leeuwenhoek (Microscopist):
Invented a simple (single-lens) microscope with superior magnification (up to 200X) for examining fabrics.
Published observations of blood, lake water, sperm, bacteria from tooth scrapings, and other microscopic life.
Matthias Schleiden and Theodor Schwann (Beginning of the Cell Theory):
Examined a wide array of specimens.
Concluded that "all organisms were composed of cells," establishing the first tenet of cell theory.
Considered a fundamental breakthrough in biomedical history, leading to the interpretation of all body functions as effects of cellular activity.
The Scientific Method
Definition: The systematic process of doing science, involving careful observation, logical reasoning, and proper analysis of observations and conclusions.
Science and its methods establish standards for truth.
The Hypothetico-Deductive Method:
The primary method for gaining physiological knowledge.
Involves formulating a hypothesis: an educated speculation or a testable possible answer to a question.
Good hypotheses are consistent with existing knowledge and are testable.
Falsifiability: For a claim to be scientifically true, it must be possible to specify evidence that would prove it wrong.
Experimental Design Elements:
Sample Size: The number of subjects included in a study.
Controls: A control group that is similar to the treatment group but does not receive the treatment, allowing for comparison.
Psychosomatic Effects: The influence of a subject's state of mind on their physiology, often tested by providing a placebo to the control group.
Experimenter Bias: Avoided by using a double-blind method, where neither the subject nor the experimenter knows who is in the control or treatment group.
Statistical Testing: Used to determine the probability that a treatment was effective.
Peer Review:
A critical evaluation by other experts in the same field.
Conducted before funding or publication to ensure verification and repeatability of results.
Maintains honesty, objectivity, and quality in scientific work.
Facts, Laws, and Theories:
Scientific Fact: Information that can be independently verified.
Law of Nature: A generalization about how matter and energy behave, derived from inductive reasoning and repeated observations. Can be stated verbally or as a mathematical formula.
Theory: An explanatory statement or set of statements derived from facts, laws, and confirmed hypotheses. It summarizes current knowledge and guides future research.
Evolutionary Perspective on the Human Body
Theory of Natural Selection: Explains how species originate and change over time, helping to understand the human body.
Charles Darwin:
An influential biologist who presented the first well-supported theory of evolution.
Authored On the Origin of Species by Means of Natural Selection (1859), known as "the book that shook the world."
Authored The Descent of Man (1871), discussing human evolution and its relationship to other animals.
Evolution, Selection, and Adaptation:
Evolution: A change in the genetic composition of a population of organisms (e.g., bacterial resistance to antibiotics).
Natural Selection: The mechanism by which evolution occurs.
Selection Pressures: Environmental forces that favor the reproductive success of some individuals over others (e.g., predators).
Adaptations: Inherited anatomical and physiological features that developed in response to selection pressures, enabling an organism to succeed (e.g., better camouflage).
Bipedalism (Walking Upright):
An adaptation involving standing and walking on two legs.
Beneficial for spotting predators, carrying food, tools, and infants.
Evolved as an adaptation to living on the savanna (grassland) when Africa's climate became hotter and drier.
Required significant skeletal and muscular modifications.
Led to changes in family structure.
Humans and chimpanzees differ by only 1.6\% of their DNA.
Impact of Arboreal Ancestors on Intelligence:
"Powerful selective forces were at work to evolve organisms with grace and agility, accurate binocular vision, versatile manipulative abilities, superb eye-hand coordination, and an intuitive grasp of Newtonian gravitation. But each of these skills required significant advances in the evolution of brains and particularly the neocortices of our ancestors. Human intelligence is fundamentally indebted to the millions of years our ancestors spent aloft in the trees."
The Hierarchy of Complexity
Human organization is based on successive levels of hierarchy, from simple to complex:
Atom: The smallest particle that retains a unique chemical identity.
Molecule: A particle composed of two or more atoms.
Macromolecules: Largest molecules, such as proteins, fats, and DNA.
Organelle: A structure within a cell that performs a specific function.
Cell: The smallest unit capable of carrying out all basic functions of life.
Tissue: Similar cells and cell products forming a discrete region of an organ, performing a specific function.
Organ: A structure composed of two or more tissue types that work together to perform a specific function. Organs have defined anatomical boundaries, and organs can exist within other organs.
Organ System: A group of organs that cooperate to perform a unique collective function (e.g., circulation, respiration, digestion).
Organism: A single, complete individual.
Characteristics of Life
Living things are distinguished from nonliving things by a collection of properties:
Organization: Living things display a higher and more complex level of organization than nonliving matter.
Cellular Composition: Living matter is always compartmentalized into one or more cells.
Metabolism: The sum of all internal chemical changes occurring within an organism.
Responsiveness (Excitability): The ability to sense and react to changes (stimuli) in the environment.
Movement: The ability of an entire organism or substances within it to move.
Homeostasis and Feedback Mechanisms
Homeostasis:
The body's ability to detect change, activate opposing mechanisms, and thus maintain relatively stable internal conditions.
The term was coined by Walter Cannon (1871 to 1945).
Loss of homeostatic control can lead to illness or death.
Negative Feedback and Homeostasis:
Allows for dynamic equilibrium: internal conditions fluctuate within a limited range around a set point.
Negative Feedback: A mechanism that keeps a variable close to its set point; the body senses a change and "negates" or reverses it.
These mechanisms are called feedback loops because they alter the original changes that triggered them.
Examples of Homeostasis in Action:
Body Temperature Regulation:
If too warm, skin blood vessels dilate (vasodilation) and sweating begins (a heat-losing mechanism).
If too cold, skin blood vessels constrict (vasoconstriction) and shivering begins (a heat-gaining mechanism).
Blood Pressure Regulation (Baroreflex):
Upon rising from a seated position, blood drains from the head, causing blood pressure to fall in that region.
Baroreceptors (receptors near the heart) detect this change and transmit signals to the cardiac center of the brainstem.
The cardiac center, acting as the integrating (control) center, processes the information and directs the effector (the heart) to increase its rate.
This increases blood pressure, restoring homeostasis.
Common Components of a Feedback Loop:
Receptor: A structure that senses a change in the body (e.g., baroreceptors monitoring blood pressure).
Integrating (Control) Center: A control center that processes sensory information, makes a decision, and directs a response (e.g., the cardiac center of the brainstem).
Effector: A cell or organ that carries out the final corrective action to restore homeostasis (e.g., the heart).
Positive Feedback and Rapid Change:
Positive Feedback: A self-amplifying cycle that leads to greater change in the same direction, rather than corrective action.
This is the normal way the body produces rapid changes.
Examples: Childbirth (uterine contractions intensify due to oxytocin), blood clotting, protein digestion, and the generation of nerve signals.
Can sometimes be dangerous (e.g., the vicious circle of runaway fever).
Gradients and Flow
Matter and energy naturally tend to flow
down gradients.Gradient: A difference in chemical concentration, charge, temperature, or pressure between two points.
Types of Gradients and Flow:
Pressure Gradient: Blood flows from a region of higher pressure to a region of lower pressure.
Concentration Gradient: Chemicals flow from an area of high concentration to low concentration.
Electrical Gradient: Charged particles flow from an area of higher electrical charge to lower electrical charge.
Electrochemical Gradient: A combination of concentration and electrical gradients.
Thermal Gradient: Heat flows from a warmer area to a cooler area.
Movement in the opposite direction (
up the gradient) requires the expenditure of metabolic energy.
Medical Terminology
Anatomical terminology is based on word elements such as roots, prefixes, and suffixes.
Root (stem): The core meaning of the word.
Combining Vowels: Join roots together to form a word.
Prefix and/or Suffix: Modify the meaning of the root word.
Acronyms: Pronounceable words formed from the first letter or few letters of a series of words (e.g., PET scan).
Plurals, Adjectives, and Possessive Forms:
Plural forms of anatomical terms vary (e.g., cortex vs. cortices, corpus vs. corpora).
Adjectives often follow the noun they modify (e.g., Biceps brachii).
The adjectival form of a term can differ from its noun form (e.g., brachium (n.) referring to the arm, vs. brachii (adj.) referring to "of the arm").
Medical Imaging
Radiography (X-rays):
Accounts for over half of all medical imaging.
X-rays penetrate tissues to darken photographic film beneath the body; dense tissues appear white.
Radiopaque substances can be injected or swallowed to highlight hollow structures like blood vessels or the intestinal tract.
Digital Subtraction Angiography (DSA): Useful for visualizing blockages and blood flow, especially in blood vessels.
Computed Tomography (CT s can):
Formerly known as a CAT scan.
Uses low-intensity X-rays and computer analysis to create slice-type images.
Offers increased image sharpness compared to traditional X-rays in some applications.
Magnetic Resonance Imaging (MRI):
Provides superior image quality compared to CT scans and involves no X-ray exposure.
Especially effective for imaging soft tissues.
Functional MRI (fMRI): Shows real-time changes in brain activity.
Positron Emission Tomography (PET):
Assesses the metabolic state of tissues.
Involves injecting radioactively labeled glucose.
Image colors indicate tissues using the most glucose at that moment; damaged or less active tissues appear dark.
Sonography (Ultrasound):
The second oldest and second most widely used imaging technique.
Uses high-frequency sound waves that echo back from internal organs to create an image.
Avoids harmful X-rays, making it safe and commonly used in obstetrics.
Produces images that are generally not as sharp as those from CT or MRI.