Tree
of Life, 7th Century BCEHistory
of Anatomy and Physiology & Homeostasis
Chapter
1
Until the modern era, Anatomy & Physiology did not exist as "sciences" -- the history of medicine reflects the history of anatomy & physiology.
Early (prerecorded history): "Shamans" were the persons with knowledge of body
functions, the use of herbs, etc..
"Healers" traditionally have three necessary qualities:
Tree
of Life, 7th Century BCE
First recorded evidence of medicine as a profession.
Code of Hammurabi contained rules related to medicine and malpractice.
"If a physician make a large incision with an operating knife and cure it, or if he open a tumor (over the eye) with an operating knife, and saves the eye, he shall receive ten shekels in money.
If the patient be a freed man, he receives five shekels.
If he be the slave of some one, his owner shall give the physician two shekels.If a physician make a large incision with the operating knife, and kill him,
or open a tumor with the operating knife, and cut out the eye, his hands shall be cut off.If a physician make a large incision in the slave of a freed man, and kill him, he shall replace the slave with another slave.
If he had opened a tumor with the operating knife, and put out his eye, he shall pay half his value.If a physician heal the broken bone or diseased soft part of a man, the patient shall pay the physician five shekels in money.
If he were a freed man he shall pay three shekels. If he were a slave his owner shall pay the physician two shekels. "
Wide use of herbs/drugs, e.g., opium.
Beer was believed to be good for the heart and liver.
Ancient Egypt: High degree of medical knowledge as evidenced by numerous medical papyri.
Egyptian Medicine: Herbs
Circumcision: Earliest record of circumcision: rite of passage for boys.
Balance of 4
body fluids or "humors." Blood (from heart, sanguine), bile (from liver;
choler), black bile (from spleen; melancholic), and phlegm (from brain; phlegmatic).
Correlation to four seasons and the four elements.
Origin
of caduceus as a symbol for medicine.
Hippocrates --"Father of Medicine." Born 460 BC.
He stressed natural causes of disease rather than displeasure of the gods.
Observational medicine which was focused on patient and patient's environment,
i.e., "holistic."
Hippocratic physicians stressed detailed observation of patient's body and body
products (sweat, urine, ear wax, feces, etc.).
"Hippocratic
Oath" & idealized doctors.
Aristotle
-- data collection, embryological observations. "The
History of Animals" , "On
Sense and the Sensible,"
and "Parts
of Animals" are some of the earliest writings dedicated to anatomy,
physiology and general biology.
Aristotle believed heart was the seat of intelligence. (Herophilus and Plato
thought that brain was).
Ptolemy established a museum in Alexandria, Egypt. Dissections allowed for a
short time.
Chinese
Medicine
Chinese medicine, like Greek-Hippocratic tradition, stressed balance (Taoist philosophy) and was primarily noninvasive (pulse reading, observational, questioning of patient).
Health is maintained when there is a balance between "yin" (female or the shaded aspect, the earth, darkness, the moon, and passivity) and "yang" (male, light, sun, heaven, the active principle in nature). There are five "Elements" in traditional Chinese medicine: wood, fire, earth, metal, and water -- water and metal are associated with yin, wood and fire are associated with yang, while earth belongs to both yin and yang because it assists both.
Roman Era
Galen -- Second century AD. "Father of Anatomy." Observational & experimental. Surgeon to gladiators in Pergamon (Turkey). Moved to Rome and eventually became physician to Emperor Marcus Aurelius. Performed pioneering experiments on circulation, respiration, urine formation, and nervous system. Stressed anatomical accuracy, but often came to the wrong conclusions based on accurate observations.
Galen's Works: On the Natural Faculties. Many of Galen's writings have been lost.
Galen was considered dogma by the Church for about 1500 years.
The "Hospital" -- from hospices
formed by early Christians for service to poor. (Similar hospices were established
by Buddhists in India and Sri Lanka).
Ancient Medical History - Homer to Vesalius. Great site which gives an overview
of ancient Western medicine!
Middle Ages
"Folk medicine"
was dominant. Greek and Roman teachings were lost.
Some women figures of note: Metrodora, Trotula,
and Hildegard of Bingen.
Metradora and Hildegard both compiled catalogs of diseases and treatments.
Hildegard's
medical and mystical writings often overlapped.
Hildegard
History
of Women In Science Resource Site
Little European progress in anatomy and physiology. Church forbade human dissection
until 1235. Galen was considered dogma and people who challenged Galen's writings
were frowned upon, occasionally burned at the stake.
Islam
Arab Moslems and Arabian Jews (e.g., Treatise on Hygiene by Rabbi
Moses Maimonides or Moshe ben Maimon), however, had well developed medical
practices, many adapted from Greek and Roman teachings. First "medical
school" in Europe in 9th Century was staffed by many Moslem and Jewish physicians.
Arabia preserved many Greek and Roman texts and reintroduced these texts to
Europe. Rhazes
(Al-Razi) and Avicenna
(lbn-Sina) were key figures in Islamic
medicine.
Ibn Sina
Many Asian and New World Indian cultures had a more advanced knowledge of medicine than Europeans at this time. Asian Indians recognized diabetes and knew that diet could affect it; early accounts of "vaccination" (variolation, actually).
New World
Medicine before Columbus
New World Indians indirectly introduced curare,
quinine, ipecac, and scurvy treatment to Europeans.
Aztecs had detailed knowledge of anatomy, especially the heart, from human sacrifices.
Renaissance:
Greater
frequency of dissections as Church's hold on science weakened.
DaVinci: "Science
comes by observation, not by authority." Merged art and anatomy.
Andreas
Vesalius: Published "De
Humani Corporis Fabrica" in 1543 when he was 28.
He is called "Father
of Modern Anatomy" because of his precise anatomical observations.
Challenged Galenic teachings.
17th and 18th Century:
William
Harvey described the circulation of blood (challenge to Galen account of
circulation) in his "On The Movement of the Heart and Blood in Animals" in 1628.
Described flow of blood in a circuit.
Anton
van Leeuwenhoek -- used microscope, observed "cells" and "animalcules."
First report of spermatozoa, blood cells, and striations in muscle.
Descartes
-- philosopher/scientist. Split mind and body. Attributed bodily functions to
mechanistic analysis. Early model of involuntary reflex. Thought pineal gland
was the site of the soul, or anatomical interface between "spirits" within body.
Basically he had a hydraulic view of the body -- nerves were hollow tubes that
conducted spirits -- spirits inflated muscles.
Jenner
-- small
pox vaccination developed from cowpox. Eventually vaccination
supplanted "variolation" (using extracts from small pox sores for inoculation)
which had been used in Europe and Asia for centuries. Lady
Montagu reported on use of variolation (often incorrectly reported as vaccination)
in Turkey, but the practice never caught on with the upper classes in England.
Jenner's
publications
Influenced by the Greek
Humoral theory, blood-letting
was widely practiced in Europe and American from the middle ages until well
into the 19th century.
19th Century:
Growth of scientific method in anatomy, physiology, and medicine.
Formulation of Cell
Theory --- Cells as the basic unit of life and "all cells come from preexisting
cells." (except first cell). Spontaneous
generation disproven
Germ
theory of disease. Advances in microscopy, staining techniques.
Pasteur:
contributed to "germ theory of disease."
Galvani
and Volta -- electrical nature of muscle and nerve function.
Darwin
-- Comparative anatomy is a reflection of evolutionary processes rather than
separate creations of God.
Surgical advances; rise of aseptic
surgery and anesthesia.
20th Century
Rediscovery of
Mendelian Genetics.
Role of chromosomes in inheritance.
Discovery of Insulin
Electron Microscope allowed fine definition of anatomical structures, e.g.,
muscle fibers, synapses.
Elucidation of protein and DNA structures.
Growth of biochemical and molecular techniques.
Cell biology, molecular biology, developmental biology (embryology), etc. all
add to the study of modern anatomy and physiology.
Imaging Technology --
X-rays, CT scans, MRIs, etc.
History of the Health Sciences
History of Medicine: Catholic Encyclopedia
Life
What is Life Anyhow?
Physiological Definition -- A Cell or Organism has:
1) Responsiveness or irritability: ability to respond to environmental change.
2) Movement or contractility
3) Metabolism--incorporates respiration, digestion, absorption, circulation,
synthesis, secretion, and excretion.
4) Growth
5) Reproduction
Viruses are often considered "non-living" since their reproduction can only occur with cells, but they are made of protein and have DNA or RNA.
BODY ORGANIZATION
Chemical:
Atoms or elements:
basic units of all matter (nucleus, electrons); 2 or more atoms form a molecule.
Molecule with 2 or more elements is a compound.
Cell: Basic structural and functional component of life. Heterogeneous in structure
and function.
Tissue: collection of cells that perform specific function
1) epithelial: linings
2) connective: support or binds other tissues
3) muscle: contractile. Skeletal, Cardiac and Smooth
4) nervous: neurons and neuroglia (supportive cells)
Organ: collection
of 2 or more tissues, integrated to perform a particular function.
E.g., stomach, heart, skin, bone.
System: collection of organs which serve a general function; digestive, nervous,
circulatory, integument, etc.
Organism: An integrated collection of systems.
Superorganism: "Integrated collection of organisms." For example,
colonies of bees, ants and termites.
Individuals have specialized functions (workers, soldiers, queen, drone). The
Borg on Star Trek.
Why is having a standard anatomical position important?
Terms of Location and Position
Superior
-- Above, toward the head
Inferior -- Below, toward the lower part of the body (Cranial and Caudal
are used for 4 legged animals)
Examples:
1) head is superior to the chest, chest in inferior to the neck
2) the knee is superior to the ankle and inferior to the hip.
Anterior -- structures or areas on or near the front surface
Posterior -- structures or regions on or near the back side of body
Examples:
1) nose is on anterior surface
2) gluteal region is on posterior surface (Dorsal and Ventral are used for 4
legged animals, but sometimes used in human anatomy -- e.g., dorsal and ventral
body cavities; dorsal root ganglion)
Medial--nearer the midline of the body
Lateral--away from the midline
Examples:
1) Nose is medial to the eyes, the eyes are lateral to the nose.
2) Medial and lateral incisors
Internal
-- deeper in the body (deep)
External -- toward the outer surface (superficial)
Examples:
1) Ribs are external to the heart and lungs
2) Internal and external iliacs and jugular vessels
3) Hair is superficial.
Proximal -- portion of structure (generally an arm or leg) that is closer
to the body
Distal --portion
of structure that is farther from the body (Proximal and Distal relate to a
structure's position relative to reference point --proximal and distal convoluted
tubules in nephron of kidney).
Examples:
1) the forearm is proximal to the hand
2) the hand is distal to the elbow
Parietal
-- refers to the walls of a cavity
Visceral --
refers to the organs contained in a cavity
Examples:
1) parietal peritoneum lines the walls of the abdominal cavity
2 ) abdominal organs are innervated by visceral nerves
Ipsilateral -- on the same side of the body
Contralateral
-- on the opposite side of the body
Examples:
1) Damage to the motor cortex results in loss of motor ability of contralateral
limbs, whereas the ipsilateral side of the body is not affected.
PLANES AND
SECTIONS
Sagittal Plane
-- divides bilateral organism into right and left sides.
Midsagittal (or Median) plane divides the body into right and
left halves that are equal in size and mirror images.
Parasagittal plane divides the body into unequal left and right sides.
Transverse or Horizontal Plane -- divides the body into superior
and inferior portions.
Frontal or Coronal Plane -- divides the body into anterior and
posterior portions (or dorsal/ventral).
Planes and Sections from Visible Human Project
Planes and Sections of Frog Embryo
Pop Quiz
CAVITIES
Dorsal Cavity = Cranial cavity + Vertebral cavity
Ventral Cavity
Consists of the:
- Thoracic Cavity--(heart + lungs)
- Abdominopelvic Cavity (Abdominal cavity, Pelvic cavity)
Abdominopelvic cavity is
divided into 9 regions or 4 quadrants
E.g., intense pain in lower right quadrant can indicate an appendicitis.
Ventral Cavity Dissection: fetal pig
BODY REGIONS
Axial -- head, neck, thorax, abdomen, and pelvis
Appendicular -- upper and lower extremities (arms and legs)
Example: Axial and Appendicular Skeleton
HOMEOSTASIS & FEEDBACK
Homeostasis
is the stability of the internal environment even though the external environment
changes.
Concepts were developed by Claude
Bernard and Walter
Cannon.
Homeostatic Regulation
Autoregulation: local
Extrinsic Regulation: involves integration of nervous and/or endocrine system.
Key things needed in a homeostatic system: receptor, control or integration
center, and effector.
Set point is the optimal level for the controlled condition. Set points can
be changed.
Feedback:
Feedback represents an organism's reception and response to some change in the
internal environment.
Negative feedback: output of system counteracts the change in the environment.
Common.
Negative feedback systems are similar to household heater-thermostat systems.
Negative feedback systems help maintain homeostasis. "Stress" can upset homeostasis.
Positive feedback: output of system is in the same direction as the change
in the environment.
System goes away from normal set point.
Positive feedback systems exist, but are rare.
Example: Labor. Uterus contracts in response to hormone oxytocin, contraction
causes more release of oxytocin, more contraction generated, more oxytocin released,
etc, etc. Self-limiting -- once child is born, uterus is no longer stretched.
Other negative
feedback systems: action potential of neurons and platelet clotting.
Homeostasis
and Diabetes:
Blood glucose
levels must be kept relatively constant. When glucose levels are elevated,
the beta cells within the pancreatic islets
of Langerhans release insulin. Insulin circulates in the blood and will bind
to receptors on the cell membrane of different tissue (muscle, liver, adipose).
The receptive tissues are stimulated to take up glucose from the blood, thus
blood glucose levels will drop. This is a classic negative feedback system.
What if a person can't produce enough insulin? What if a person produces insulin,
but the tissues are less sensitive than normal? Both conditions will result
in high levels of blood glucose. The above conditions are the two types of diabetes
mellitus.
Homeostasis and Body Weight Control
Is there a set point for body weight? Maybe.
MISC LINKS
Folk Healing, Alternative and Parallel Medicine
History of the Warfare of Science with Theology in Christendom: From Miracles to Medicine