A&P Chapter 1: The Form and Function of Life

Anatomy

the study of structure and organization of living organisms

Computed tomography (CT)

Low intensity x-rays and computer analysis, slice type image typically transverse, increased sharpness of an image

Magnetic resonance imaging (MRI)

Superior quality to CT scan and no X-ray exposure, best for soft tissue

Functional MRI

Shows real time changes in the brain

Positron emission tomography (PET)

Assesses metabolic state of tissue with injected radioactively labeled glucose, image color shows tissues using the most glucose at that moment and damaged tissues appear dark

Sonography

Second oldest and second most widely used, high frequency sound waves echo back from internal organs, avoids harmful x-rays so good for obstetrics, image not very sharp

Radiography (X-rays)

Over half of all medical imaging, Penetrate tissues to darken photographic film beneath the body; dense tissue appears white

Radiopaque substances can be injected or swallowed to fill hollow structures, for example, blood vessels, intestinal tract

Digital subtraction angiography (DSA)

Type of radiography useful for showing blockages and blood flow

Physiology

the study of function of living organisms and their parts

Inspection

simply looking at the body’s appearance (performing a physical exam or making a diagnosis from surface appearance)

Palpation

feeling a structure with the hands (palpating a swollen lymph node or taking a pulse)

Auscultation

listening to the natural sounds made by the body (listening to heart and lung sounds)

Percussion

examiner taps on the body, feels for abnormal resistance, and listens to the emitted sound for signs of abnormalities (such as pockets of fluid, air, or scar tissue)

Dissection

Carefully cutting and separating tissues to reveal their relationships. Was also known as anatomizing until the 19th century. One of the first steps in training students is dissection of the cadaver.

Comparative anatomy

Study of multiple species in order to examine similarities and differences and analyze evolutionary trends. Anatomy students often begin by dissecting other animals with which we share a common ancestry and many structural similarities. Basis of development of new drugs and medical procedures.

How was it once common to diagnose disorders? What replaced it?

It was common to perform exploratory surgery. Now it has been mostly replaced by medical imaging techniques.

Radiology

Methods of viewing the inside of the body without surgery

Gross anatomy

Structures that can be seen with the naked eye, whether by surface observation, radiology, or dissection

Histology

study of tissue structures, microscopic anatomy

Cytology

Study of the structure and function of individual cells

Ultrastructure

Refers to fine detail study, down to molecular level revealed by electron microscope

Through what have we learned much of our knowledge on bodily function?

Comparative physiology. We have learned about processes such as water balance, respiration, and reproduction through these studies.

Examples of inspection

Performing a physical exam or making a diagnosis from surface appearance

Examples of palpation

Palpating a swollen lymph node or taking a pulse

Examples of auscultation

Listening to heart and lung sounds

Examples of comparative anatomy

Cardiac surgeon will perform on animals before humans, and vaccines are tested on animals until it demonstrates significant benefits without unacceptable risk.

Examples of percussion

Tapping on pockets of fluid, air, or scar tissue

What was the earliest adoption of medicine?

As early as 3,000 years ago, physicians in Mesopotamia and Egypt treated patients with herbal drugs, salts, physical therapy, and faith healing

Hippocrates

(460-375 BCE) Greek physician known as “father of medicine”. He established a code of ethics for physicians and urged them to stop attributing disease to the activities of gods and demons and to seek their natural causes.

Aristotle

(384-322 BCE) Greek physician. He was one of the first philosophers to write about anatomy and physiology. He believed diseases and other natural events could have supernatural causes or natural ones. He aimed to identify unifying themes in nature based on animals. He argued complex structures are built from a smaller variety of simple components.

Physici or Physiologi

Belief that diseases and other natural events have natural causes

Theologi

Belief that diseases and other natural events have supernatural causes

Metrodora

(c. 200 BCE) Greek physician who was the first woman to publish a medical textbook on gynecological studies

Claudius Galen

(129-200) Physician to Roman gladiators who wrote the most influential medical textbook of the ancient era. Cadaver dissections were banned in his time so dissections of animals formed his basis of knowledge. Made som incorrect deductions, such as his description of the human liver based on a baboon. He saw science as a method of discover.

State of medical science in the Middle Ages

It varied greatly from one religious culture to another. Science was severely repressed in the Christian culture of Europe until about the 16th century. Professors taught medicine as a commentary on Galen and Aristotle. Free inquiry was less inhibited in Jewish and Muslim culture at the time.

Where did the world influenza come from?

Medieval medical pseudoscience such as astrological diagnoses

Maimonides

(1135-1204) Accomplished Jewish physician, as well as admired rabbi living in Egypt. He wrote 10 medical books on diseases.

Avicenna (or Ibn Sina)

(980-1037) Wrote The Canon of Medicine which became a leading authority in European medical schools for over 500 years.

When did modern Western medicine begin?

Around the 16th century or 1500s

Andreas Vesalius

(1514-1564) Anatomist who taught anatomy in Italy. He was the first to publish accurate illustrations for teaching anatomy, and pointed our much of Galen was wrong. Catholic Church had relaxed prohibition on cadaver use. Dissection gradually found its way into training of medical students.

William Harvey

(1564-1642) Englishman, leading figure on physiology. Remembered for his studies of blood circulation. Contributions represented the birth of experimental physiology.

Galileo

(1564-1642) Patented the compound microscope as a by-product of his work with telescopes

Marcello Malpighi

(1628-1694) Among the first to observed blood cells and capillaries as well as capillary blood flow through telescope. Known as the father of histology

Robert Hooke

(1635-1703) Designed scientific instruments of various kinds, improved optics and invented several of the helpful features found in microscopes today. Studied cells such as cork plant cells.

Antony van Leeuwenhoek

(1632-1723) Textile merchant who invented a simple (single lens) microscope though it became a toy for the upper class

Matthias Schleiden and Theodor Schwann

By 1830, they concluded that all organisms were composed of cells. This created the basis for cell theory

Cell theory

All functions of the body are now interpreted as the effects of cellular activity

Examples of modern advancements in science

Germ theory of disease, mechanisms of heredity, the structure of DNA, medical imaging, chemotherapy, immunizations, anesthesia, genetics

Scientific method

A highly variable method that will find objective conclusions that will stand up to efforts to find fault with them.

Inductive Method

Process of making numerous observations until one feels confident in drawing generalizations and predictions from them. Basis of our knowledge of anatomy.

What is considered proof in science?

We can consider a statement as proven beyond reasonable doubt if it was arrived at by reliable methods of observation, tested and confirmed repeatedly, and not falsified by any credible observation

Hypothetico-Deductive Method

Begins by asking a question and formulating a hypothesis. An experiment yields observations that either support hypothesis or require the scientist to modify, abandon, formulate a better hypothesis to test.

Hypothesis

An educated speculation or possible answer to a question. Must be 1) consistent with what is already known 2) capable of being tested and possibly falsified by evidence

Falsifiability

If we claim something is scientifically true, we must be able to specify what evidence it would take to prove it wrong. If nothing could possibly prove it wrong, it’s not scientific.

Examples of what to consider when making an experimental design

Sample size, controls, experimenter bias, statistical testing

Sample size

the number of subjects used in a study

Control group

consists of subjects that are as much like the treatment group as possible except with respect to the variable being tested

Psychosomatic effects

Effects of the subject’s state of mind on his or her physiology. Can have undesirable effect on experimental results

Placebo

a substance with no significant physiological effect on the body

Double-blind method

Procedure in which neither the subject to whom a treatment is given nor the person giving it and recording the results knows whether that subject is receiving the experimental treatment or the placebo.

Peer review

Critical evaluation by other experts in that field. Important to be able to replicate results of an experiment.

Scientific fact

Information that can be independently verified by any trained person

Law of nature

Generalization about the predictable ways in which matter and energy behave. Result of inductive reasoning based on repeated confirmed observations.

Theory

Explanatory statement or set of statements derived from facts, laws, and confirmed hypotheses

Two theories with the broadest implications for the human body

Cell theory and the theory of natural selection

Charles Darwin

(1809-1882) Influential biologist who created the theory of natural selection

Evolution

Change in the genetic composition of a population of organisms

Natural selection

Some individuals have hereditary advantages over competitors that enable them to produce more offspring. They pass these advantages to their offspring and such characteristics therefore become more and more common in successive generations. This brings about the generic change in a population that constitutes evolution.

Selection pressures

Natural forces that promote the reproductive success of some individuals more than others

Examples of selection pressures

Climate, predators, disease, competition, and food

Adaptations

Features of anatomy, physiology, and behavior that evolve in response to these selection pressures and enable an organism to cope with the challenges of its environment

Model

An animal species or strain selected for research on a particular problem

Vestigial organs

Remnants of organs that apparently were better developed and more functional in the ancestors of a species

Examples of vestigial organs

Arrector muscles for each of our hairs

Who do we share closest common ancestry to?

Monkeys and apes

How did our ancestors adapt over time to evolve into humans?

We evolved to have more mobile shoulders, have opposable thumbs, prehensile hands, stereoscopic vision (depth perception), and full color vision

What adaptations occurred to allows us to evolve to bipedalism 4 million years ago?

Pelvis, femur, knee, great toe, foot arches, spinal column, skull, arms, and many muscles

Evolutionary medicine

Analyzes how human disease and dysfunctions can be traced to differences between the artificial environment in which we now live and the prehistoric environment to which homo sapiens was biologically adapted

Hierarchy for complexity of humans

Organism > Organ system > Organ > Tissue > Cell > Organelle > Molecule > Atom

Organism

single complete individual

Organ system

Group of organs with a unique collective function

How many organ systems does the human body have?

11 organ systems

Organ

Structure composed of two or more tissue types that work together to carry out a particular function. They can be gross anatomy or ultrastructure.

Which organs belong to two organ systems

Pancreas- endocrine & digestive systems

Pharynx- respiratory & digestive

Kidneys- Urinary and endocrine

Tissue

mass of similar cells and and cell products that forms a discrete region of an organ and performs a specific function

What are the four classes of tissue?

Epithelial, Connective, Nervous, and Muscular

Cells

Smallest units of an organism that carry out all the basic functions of life; nothing simpler than a cell is considered alive

Organelles

Microscopic structures in a cell that carry out its individual functions, are composed of molecules

Macromolecules

Largest molecules such as fats, proteins, and DNA

Reductionism

Theory that a large, complex system such as the human body can be understood by studying its simpler components, first thought by Aristotle

Holism

Complementary theory that there are “emergent properties” of the whole organism that cannot be predicted from the properties of its separate parts-- human beings are more than the sum of their parts

Situs solitus

normal arrangement of organs

Situs inversus

Organs of thoracic and abdominal cavities are reversed between right and left

Dextrocardia

A selective right-left reversal of the heart

Situs perversus

A single organ occupies an atypical position

What are the 8 universal characteristics of life?

Organization, cellular composition, metabolism, responsiveness and movement, homeostasis, growth and development, reproduction, and evolution

Organization

Living things exhibit a far higher level of organization than the nonliving world around them. They expand a great deal of energy to maintain order and a breakdown of this order is accompanied by disease and death

Cellular composition

Living matter is always compartmentalized into one or more cells

Metabolism

Sum of all internal chemical change. Living things take in molecules from the environment and chemically change them into molecules that form their own structures, control their physiology, or provide them with energy.

Responsiveness & Movement

Ability to sense an react to stimuli changes in the environment. All organisms and cells are at least capable of moving substances internally.