Chapter 1: The Study of Anatomy and Physiology

Human Anatomy
the study of the structural basis of body function
Human Physiology
the study of the functional relevance of human structure
Gross Anatomy
is structure visible to the naked eye, either by surface observation or dissection
histology (microscopic anatomy)
stained and thinly sliced tissue specimens observed under a microscope
histopathology
the microscopic examination of tissues for signs of disease
surface anatomy
the external structure of the body and is especially important in conducting a physical examination of a patient
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systematic anatomy
the study of one organ system at a time (intro. textbooks)
regional anatomy
the study of multiple organ systems at the same time in a given region of the body, such as the head or chest (medical schools)
functional morphology
the study of both the structure of the organs and the functional reasons behind that structure
comparative anatomy
the study of more than one species in order to learn generalizations, evolutionary trends, and structure-function relationships (ex: chimpanzee pelvis vs. human pelvis)
inspection
the simplest method of examine the body/surface structures, such as physicians performing a physical examination
dissection
the careful cutting and separation of tissues to reveal their relationships
cadaver
the dissection of a dead human body
palpation
is feeling structures with the fingertips, such as a palpitating swollen lymph node or taking a pulse
auscultation
is listening to the natural sounds made by the body, such as heart and lung sounds
percussion
is tapping on the body and listening to the sound for signs of abnormalities such as pockets of fluid or air
medical imaging
includes methods of viewing the inside if the body without surgery/dissection. The branch of medicine concerned with imaging is called radiology
noninvasive
exploratory techniques that allow physicians to see inside the body without cutting
invasive
techniques that may entail inserting ultrasound probes into the esophagus, vagina, or rectum to get close to the organ to be imaged, or injecting substances into the bloodstream or body passages to enhance image formation
radiography
is the process of photographing internal structures with X-rays, a form of high-energy radiation.
X-ray
Form of high-energy radiation
Absorbed by dense tissues, e.g., bone
produce a lighter image than soft tissues
Computed tomography (the CT scan)
is a more sophisticated application of X-rays.
-Emits low-intensity X-rays
-Produces an image of a “slice” of body
-Little organ overlap
-Image much sharper than conventional X-ray
-Useful for identifying tumors, aneurysms, cerebral hemorrhages, kidney stones, and other abnormalities
Magnetic resonance imaging (MRI)
is even better than CT for visualizing soft tissues (e.g., distinguishing white and gray matter of brain)
-Patient surrounded by a large electromagnet
-Tissue response to magnetic field and radio waves
-Computer analysis of signal to produce image
-“Sees” clearly through skull and vertebral column
Positron emission tomography (PET scan)
Can assess metabolic state of tissue
Injection of radioactively labeled glucose
Highlights tissues most actively consuming energy
E.g., in cardiology
can show extent of damaged heart tissue
An example of nuclear medicine
radioisotopes to treat disease or form diagnostic images
Sonography
uses a handheld device placed firmly against the skin; it emits high-frequency ultrasound and receives signals reflected back from internal organs.
-Avoids harmful effects of X-rays
-Equipment inexpensive and portable
-Does not produce very sharp image
-Echocardiography, sonographic exam of beating heart
Organization
living things exhibit a far higher level or organization than the nonliving world around them. They expends a great deal of energy to maintain order, and disease and death result from a breakdown in this order
cells
living matter is always compartmentalized into one or more cells
metabolism
living things take in molecules from the environment and chemically change them into molecules that form their own structures, control their physiology, or provide energy. Metabolism is the sum of all this internal chemical change. There is a constant turnover of molecules in the body although you sense a continuity go personality and experienced from your childhood to the present, nearly every molecule of your body has been replaced within the past year
growth
occurs through metabolic change
mostly composed of molecules made by chemically altering food
development
change in form or function over lifetime of organism
includes differentiation
transformation of cells and tissues with no specialized function
become cells committed to particular task
e.g., unspecialized tissue called mesoderm
differentiates into muscle, bone, cartilage, and blood
excitability
ability of organisms to sense and react to stimuli
occurs at all levels from cell to entire body
especially obvious in animals
homeostasis
ability to maintain internal stability
despite changing external environment
e.g., stable temperature, blood pressure, and body weight

Ability to maintain internal stability
e.g., body temperature maintained within range
e.g., blood pressure and body weight
e.g., electrolyte balance and pH
Loss of homeostatic control
tends to cause illness or death
Pathophysiology
study of unstable conditions
result when homeostatic controls go awry

reproduction
organisms able to produce copies of themselves
pass their genes on to offspring
evolution
genetic change in the population over time
seen only in population as a whole
new variations introduced by mutations
some variations favored by environment
evolutionary medicine
interprets disease in terms of biological history of species
negative feedback
a process in which the body senses a change and activates mechanisms that negate/reverse it.
-Maintains homeostasis
-Change sensed by body
-activates mechanisms that reverse it
-Does not produce absolute constancy
-maintains physiological values within narrow range
-conditions fluctuate slightly around set point
-Key mechanism for maintaining health