A&P Ch 9: The Nervous System: The Brain & Cranial Nerves
meninges
3 layers of connective tissue that surround both the brain & spinal cord to form a complete enclosure
corpus callosum
a band of white matter at the bottom of the longitudinal fissure; is a bridge between the R & L hemispheres, allowing impulses to cross from one side of the brain to the other
cerebrospinal fluid (CSF)
a clear liquid that circulated in & around the brain & spinal cord; it's function is to support nervous tissue & to cushion shocks, also carries nutrients to the cells & transports waste away
longitudinal fissure
a deep groove dividing the cerebrum into R & L hemispheres
choroid plexus
a network of ependymal cells & blood vessels, which makes CSF within all four ventricles
cerebral aqueduct
a small canal in the midbrain
cerebral cortex
a thin layer of gray matter covering each cerebral hemisphere
hypoglossal (XII)
carries impulses controlling tongue muscles (motor)
vagus (X)
carries motor impulses to most organs in the thoracic & abdominal cavities, also contains motor fibers to the larynx (motor); is the longest cranial nerve, name means "the wanderer"
vestibulocochlear (VIII)
carries sensory impulses for hearing & equilibrium from the inner ear (sensory)
glossopharyngeal (IX)
carries sensory impulses from the tongue & pharynx; controls swallowing muscles & stimulates the parotid salivary gland (mixed)
pons
connects cerebellum with other portions of the brain; helps regulate respiration
midbrain
connects cerebrum with lower portions of the brain; has reflex centers concerned with vision & hearing;
facial (VII)
controls the muscles of facial expressions, also includes sensory fibers for taste and secretory fibers to the smaller salivary glands & the lacrimal gland (mixed)
lateral sulcus
curves along the side of each hemisphere & separates the temporal lobe from the frontal & parietal lobes
gyri
elevated portions of the brain (singular is gyrus)
ventricles
four fluid-filled spaces in the brain
accessory (XI)
has 2 branches, one controls the trapezius & SCM, the other controls the larynx (motor)
trigeminal (V)
has 3 branches; all 3 branches carry general sensory impulses from the eye, upper jaw & lower jaw, 3rd branch also has motor fibers to the muscles of mastication (mixed)
premotor cortex
helps plan complex movements
pia mater
innermost layer of the meninges, attached to the nervous tissue of the brain & spinal cord, follows all contours of these structures; (pia mater means "soft mother")
prefrontal cortex
involved in memory, problem solving & conscious thought
frontal lobe
lies anterior to the central sulcus; gyrus just anterior to central sulcus contains a primary motor area
central sulcus
lies between the frontal & parietal lobes of each hemisphere at right angles to the longitudinal fissure
medulla oblongata
links the brain with the spinal cord; has centers for control of vital functions, such as respiration & heartbeat
hypothalamus
maintains homeostasis, controls autonomic nervous system & pituitary gland
oculomotor (III)
moves eyeball & eyelid, adjusts the pupil & lens of the eye (motor)
trochlear (IV)
moves eyeball (motor)
parietal lobe
occupies the superior part of each hemisphere & lies posterior to the central sulcus
dura mater
outermost layer of the meninges; thickest & toughest layer (dura mater means "hard mother"); is in 2 layers around the brain, outer layer is fused to the crainal bones; is in single layer around the spinal cord
Broca area
plans the sequences of muscle contractions in the tongue, larynx & soft palate required to form meaningful sentences (usually found in the L hemisphere)
cerebellum
posterior to the brain stem & is connected with the cerebrum, brain stem & spinal cord by means of the pons; coordinates voluntary muscles, maintains balance & muscle tone; (cerebellum means "little brain", also divided into 2 hemispheres)
primary motor area
provides conscious control of skeletal muscles
abducens (VI)
sends motor impulses to an eyeball muscle (motor)
sulci
shallow grooves in the brain (singular is sulcus)
optic (II)
sight (sensory)
diencephalon
sits in the center of the brain between the two hemispheres and superior to the brain stem; includes the thalamus & the hypothalamus
interventricular foramina
small openings from the lateral ventricles into the 3rd ventricle
olfactory (I)
smell (sensory)
thalamus
sorts & redirects sensory input
brain stem
spans the region between the diencephalon & spinal cord; superior portion is the midbrain, inferior to that is the pons, followed by the medulla oblongata
arachnoid
the middle layer of the meninges; is loosely attached to the pia mater by weblike fibers, forming a space (subarachnoid space) where CSF circulates
cerebrum
the most superior & largest part of the brain; consists of L & R hemispheres which are each divided into lobes
dural sinuses
where the 2 layers of the dura mater separate to provide venous channels for the drainage of blood coming from brain capillaries