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BIOL 2304 Lecture Notes
Chapter 1, page 1
Orientation to the Body
A. hierarchy of structural organization
1. chemical = atoms bonded together to make up molecules
2. cellular = basic units of living things
3. tissue = group of cells that perform the same function
4. organ = structure made of more than one tissue; performs a specialized
function
5. system = group of organs that perform related functions
6. organism = sum of all organ systems working together
B. directional terms
1. use of medial and lateral in hands and feet
2. use of proximal and distal in extremities
3. anterior vs ventral and posterior vs dorsal
4. quadruped vs biped
Strong/Fall 2008
BIOL 2304 Lecture Notes
Chapter 1, page 2
C. body planes and sections
1. sagittal - divides body into left and right parts
median/midsagittal - divides body into equal left and right parts
parasagittal - any sagittal section other than the midsagittal
2. frontal - divides body into anterior and posterior parts
coronal - usually used to describe a frontal section of the brain
3. transverse - divides body into superior and inferior parts (also called horizontal
section and cross section)
4. individual organs are sometimes sectioned in the same planes as the body,
but taken out of the context of anatomical position, other terms describing
the type of section may be more appropriate:
a. a section of an organ that is perpendicular to its axis can be called a
transverse section (t.s.) or cross section (c.s., or x.s. )
b. a section of an organ parallel to its longitudinal axis is called a
longitudinal section (l.s.)
Strong/Fall 2008
BIOL 2304 Lecture Notes
Chapter 1, page 3
D. body plan
1. tube in a tube
2. bilateral symmetry
3. dorsal hollow nerve cord
4. notochord and vertebrae
5. segmentation
6. pharyngeal pouches
E. body cavities
 are closed (do not open to the outside of the body
 are lined by membranes
1. dorsal body cavity
a. cranial cavity
 enclosed by cranial bones of skull
 encases the brain
b. vertebral cavity
 enclosed by vertebrae (spinal column, vertebral column)
 encases the spinal cord
Strong/Fall 2008
BIOL 2304 Lecture Notes
Chapter 1, page 4
2. ventral
a. thoracic
 enclosed by ribs, muscles (including the diaphragm), sternum and
vertebrae
 contains lungs and mediastinum (area between lungs containing
heart, trachea, esophagus, aorta)
b. abdominopelvic
 separated from thoracic cavity by diaphragm
 enclosed by abdominal muscles, vertebrae, pelvis and pelvic
diaphragm (muscles)
abdominal region is superior to pelvic region; they are separated by
an imaginary plane that goes across the pelvic brim
Strong/Fall 2008
BIOL 2304 Lecture Notes
Chapter 1, page 5
3. serous membranes
 found in ventral body cavity
 secrete a watery fluid
 consist of two layers that are continuous with each other and
enclose a thin, fluid-filled serous cavity or space (there are
no organs in the serous cavities--only fluid)
 parietal layer - attached to inner wall of body cavity (line the body
cavity)
 visceral layer - attached to outer surface of organs in the cavity
a. pleura/pleurae
the lungs are surrounded by the pleural cavity
b. serous pericardium
the heart is surrounded by the pericardial cavity
Strong/Fall 2008
BIOL 2304 Lecture Notes
Chapter 1, page 6
c. peritoneum
some abdominal and pelvic organs are surrounded by the
peritoneal cavity
F. microscopic anatomy (histology)
"most physiological and disease processes take place at the cell and tissue level"
micrograph = picture taken through a microscope
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
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light microscope (LM) - tissues, cells, nuclei
transmission electron microscope (EM,TEM) - subcellular details in
section
scanning electron microscope (SEM) - 3-D views of surfaces
Strong/Fall 2008