Chapter Two Notes
Phrenology argued that a person’s character could be determined by feeling the
lumps on the skull.
Anatomical Direction and Planes of section
rostral/anterior (RAHS-truhl)A directional term meaning toward the head of a four-
caudal/posterior (KAW-duhl)A directional term meaning toward the tail of a four-
inferior / ventral A directional term meaning toward the belly of a four-legged
superior / dorsal A directional term meaning toward the back of a four legged
neuraxis (ner-AX-is)Animaginary line that runs the length of the spinal cord to the
front of the brain – 90 deg bend in humans, straight in 4 legged animals
midline Animaginarylinedividing the body into two equal halves.
ipsilateral Adirectionalterm referring to structures on the same side of the midline.
contralateral Adirectional term referring to structures on opposite sides of the
medial Adirectionalterm meaning toward the midline.
lateral Adirectionaltermmeaning away from the midline.
proximal Adirectionaltermthat means closer to center; usually applied to limbs;
opposite of distal.
distal Adirectionalterm meaning farther away from another structure, usually in
reference to limbs.
coronalsection Ananatomical section dividing the brain front to back, parallel to the
face. Also known as a frontal section.
sagittalsection (SA-ji-tuhl) An anatomical section that is parallel to the midline.
midsagittalsection Asagittal section that divides the brain into two approximately
horizontal/axialsection (AX-ee- uhl) An anatomical section
that divides the
from top to bottom
Protecting and Supplying the Nervous System
Babies born with a soft spot, or fontanel – takes 18 months to fuse
meninges (meh-NIN-jees)The layers of membranes that cover the central nervous
and the peripheral nerves.
Going from the skull to the brain, we find the dura mater, the arachnoid layer, and
the pia mater. Between the arachnoid and pia mater layers is the subarachnoid
space, which contains cerebrospinal fluid. In
the peripheral nervous system, only the dura mater and pia mater layers cover the
nerves. There is no cerebrospinal fluid in the peripheral nervous system.
Only the dura mater and pia mater cover nerves that exit the brain and spinal cord.
These nerves are referred to as the peripheral nervous system Viruses and bacteria can invade the layers of the meninges, causing meningitis.
Meningitis causes headache and stiffness of the neck, which can be followed by
incoherence, drowsiness, coma, and death.
cerebrospinal fluid (CSF) is produced by the choroid plexus that lines the walls of
the ventricles. From the lateral ventricles, the CSF flows through the third and
fourth ventricle and into the central canal of the spinal cord. At the base of the
cerebellum, CSF exits into the subarachnoid space and is reabsorbed by veins near
the top of the head.
CSF cushions the brain and prevents neurons from responding to pressure. Turned
over 3 times a day
Hydrocephalus –blockage in CSF circulation, can cause mental retardation
Blood reaches the brain either through the carotid arteries on either side of the neck
or through the vertebral arteries entering through the base of the skull. Once in the
brain, these arteries branch into the anterior cerebral artery, the middle cerebral
artery, and the posterior cerebral artery.
Significant brain damage occurs less than three min- utes after the stopping of a
=brain and spinal chord – encased in bone – damage here is permanent
PNS=nerves – not encased in bone – damage here is not permanent
Based on the points of exit, we divide the spinal cord into 31 segments. Starting
closest to the brain, there are eight cervical nerves that serve the area of the head,
neck, and arms.
12 thoracic nerves, which serve most of the torso.
Five lumbar nerves come next, serving the lower back and legs
five sacral nerves serve the backs of the legs and the genitals
single coccygeal nerve.
White matter = axons
Dorsal = sensory
Grey matter = cell bodies
Dorsal horn receive sensory, ventral horn receive motor (voluntary or reflexive)
Patellar reflex – 2 neurons involeved (sensory and motor)
Withdrawal – 3 involved (sensory, motor and interneuaron)
Cervical damage – quadrapalegic, lmbar damage-parapelegic
-just abpve the spinal chord the brain divides into three parts: the hindbrain, midbrain (or mesencephalon), and
forebrain. Together, the hindbrain and midbrain make up the brainstem.
he hindbrain divides into the myelencephalon, or medulla, and the metencephalon.
hindbrain Themostcaudal division of the brain, including the medulla, pons, and
midbrain The division of the brain lying between the hindbrain and forebrain.
forebrain Thedivisionofthe brain containing the diencephalon and the
brainstem The lower two thirds of the brain, including the hindbrain and midbrain.
myelencephalon / medulla
(my-len-SEF-ah-lon, muh- DOO-luh) The most caudal part of the hindbrain.
metencephalon (met-en- SEF-uh-lon) The division of the hindbrain containing the
pons and cerebellum.
nuclei Collectionsofcellbodies that share a function.
reticularformation (reh- TIK-you-ler) A collection of brainstem nuclei, located near
the midline from the rostral medulla up into the midbrain, that regulate sleep and
pons Astructurelocatedinthe metencephalon between the medulla and midbrain;
part of the brainstem located in the hindbrain.
um) A structure located in the metencephalon that
participates in balance, muscle tone, muscle coordination, some types of learning,
and possibly higher cognitive functions in humans.
cochlearnucleus (KOKE-lee- er) A nucleus found in the pons that receives
information about sound from the inner ear.
vestibularnucleus (ves-TIB- you-lar) A group of cell bodies
in the pons that receive
input about the location and movement of the head from sensory structures in the
raphenuclei (RAH-fay) Nuclei located in the pons that participate in the
of sleep and arousal.
Locus coeruleus (LOW-kuss se-ROOlee-us) A structure in the pons that participates
mesencephalon Another term for midbrain, the division of the brain lying between
the hindbrain and forebrain.
tectum The“roof,”ordorsal half, of the midbrain.
tegmentum (teg-MEN-tum) The “covering,” or ventral half of the midbrain.
cerebralaqueduct (ser-EE-bruhl AHkwi-dukt) The small channel running along the
the midbrain that connects the third and fourth ventricles. It seperates
the tectum from the tegmentum
periaqueductalgray (pear-ee- AHkweh-duk-tuhl) Gray matter surrounding the
cerebral aqueduct of the midbrain that is believed to play a role in the sensation of
Red nucleus Astructurelocated within the reticular formation that communicates
motor information between the spinal cord and the cerebellum. substantianigra (sub-STAN- shuh NIE-gruh) Midbrain nuclei that communicate with
basal ganglia of the forebrain. Degeneration results in parkinsons
superiorcolliculi (kohl-IK- you-lee) A pair of bumps on the dorsal surface of the
midbrain that coordinate visually guided movements and visual reflexes.
Inferior colliculi Apairof bumps on the dorsal surface of the midbrain that process
auditory information. Auditory reflex