Four main regions of the brain
the brain stem (connected to the superior part of the spinal cord), cerebellum (posterior to the brain stem), diencephalon (superior to the brain stem, in the center of the brain), and cerebrum (the dominant brain structure, envelops the diencephalon)
Brain stem
connected to the superior part of the spinal cord; comprised of 3 structures: the medulla oblongata, the pons, and the midbrain
Medulla oblongata
immediately superior to the spinal cord; houses the respiratory (rate and depth of breathing) and cardiovascular (rate and force of heartbeat and blood pressure reflexes) control centers
Pons
an expanded structure located superior to the medulla oblongata and anterior to the cerebellum; has respiratory centers that assist the medulla oblongtata in controlling breathing; also relays information to the diencephalon and the cerebellum
Midbrain
a smaller area superior to teh pons and inferior to teh diencephalon, consisting of cerebral peduncles and the corpora quadrigemina
Cerebral peduncles
are white fibers that connect the upper and lower brain areas
Corpora quadrigemina
are composed of 2 superior colliculi and 2 inferior colliculi
Superior colliculi
part of the corpora quadrigemina; have reflex centers involved in eye, head, and neck movments with visual stimulation
Inferior colliculi
part of the corpora quadrigemina; have reflex centers involved in auditory stimuli that result in head and trunk movements
Cerebellum
is second in size to the cerebrum and is located inferior to it and posterior to the medulla and pons; there are 2 cerebellar hemispheres, with the vermis connecting them; regulates posture and balance, and in addition, smoothes and coordinates skilled sk
Vermis
central area of the cerebellum that connects the 2 cerebellar hemispheres
Arbor vitae
white matter found in the cerebellum appearing as branches of a tree
Cerebellar cortex
the outer layer of gray matter of the cerebellum
Folia
slender, pleated folds of the cerebellum that increase the surface area allowing for more neuron cell bodies
Diencephalon
located in the brain's central area and has 3 main regions: the thalamus, the hypothalamus, and the epithalamus
Thalamus
is composed of the paired, egg-shaped bodies centrally located in teh diencephalon and comprises approximately 80% of this structure; this is the principal relay station for sensory fibers and some somatic motor fibers; this also filters out unnecesary se
Intermediate mass
each cerebral hemisphere contains half of the thalamus, which is connected by a small bridge called teh ...
Hypothalamus
is located below the thalamus and is a quadrangular-shaped structure; has important nuclei that control many body functions and homeostasis; some of the major functions include integrating and controlling the pituitary gland and hormonal functions, autono
Infundibulum
a stalk that connects the pituitary gland to the hypothalamus
Mammilary bodies
two small, round masses located ust posterior to the infundibulum; are relay stations for smell and taste reflexes
Optic chiasm
the area where the optic nerves cross, is anterior to the infundibulum
Pituitary gland
looksl ike a large pea and is attached to the end of the infundibulum; is controlled by the hypothalamus
Epithalamus
is superior and posterior to the thalamus and includes the pineal gland (or body)
Pineal gland
part of the epithalamus; a small endocrine gland taht secretes the hormone melatonin
Cerebrum
is made up of right and left cerebral hemispheres and is the largest and most complex division of the brain; is superior to and surrounds the diencephalon and part of the brain stem; is the center of higher mental processes such as intelligence, communica
Cerebral cortex
is the superficial gray matter on the exterior of the cerebrum composed of nerve cell bodies and dendrites; integrates sensory information, initiates motor output, and is also invlved in emotions and intellectual processes
Basal ganglia
areas of gray matter composed of paired nuclei (clusters of neuron cell bodies in the CNS) that are found deep within each cerebral hemisphere; they control automatic skeletal muscle movment and are involved with the limbic system (emotional brain)
Cerebral white matter
lies deep to the outer cortex and is comprised mostly of myelinated axons that give it the white appearance; are organized into commissural, association, and projection fibers
Corpus callosum
a prominent commissural fiber tract that is readily observable in midsagittal sections of the brain; connects the two cerebral hemispheres
Commissural fibers
transmit nerve impulses between the two hemispheres
Association fibers
transmit nerve impuleses within the same hemisphere
Projection fibers
are ascending and descending tracts that project nerve impulses from inferior to superior brain areas or vice versa
Lobes of the cerebrum
frontal, parietal, occipital and temporal
Gyrus
elevation or fold in the cerebral cortex; increase the surface area for neuron cell bodies
Sulcus
shallow groove between elevations
Central sulcus
shallow groove separating frontal lobe from parietal lobe
Longitudinal fissure
deep groove separating the 2 cerebral hemispheres at the midline
Precentral gyrus
elevation located just anterior to the central sulcus
Postcentral gyrus
elevation located just posterior to the central sulcus
Transverse fissure
deep groove separating the cerebrum from teh cerebellum in teh posterior/inferior part of the brain
Anterior cranial fossae
support the frontal lobes of the cerebrum
Middle cranial fossae
support portions of the temporal and parietal lobes of the cerebrum and the diencephalon
Posterior cranial fossae
support portions of the temporal, parietal, and occipital lobes of the cerebrum, teh cerebellum, and the brain stem
Three cranial meninges
connective tissue membranes: the dura mater, arachnoid mater, and pia mater
Dura mater
the first meninx; located deep to the cranial bones; it is comprised of the periosteal layer and the meningeal layer; the double-layered dura mater extends deep into the longitudinal fissure forming teh falx cerebri, into the transverse fissure forming th
Dural sinuses
the 2 dural layers split to form the dural sinuses, which eventually drain cranial blodo into the jugular veins
Superior sagittal sinus
located superior to the longitudinal fissure; is one of the main dural sinuses
Periosteal layer
part of the dura mater; a tough membrane attached to the cranial bones
Meningeal layer
part of the dura mater; exterior to the arachnoid mater
Arachnoid mater
the 2nd meninx located deep to the dura mater; projections of the arachnoid mater into the dural sunuses are called arachnoid villi
Pia mater
the thin, inner meninx; it hugs and overlays the cerebral cortex, following each gyrus and sulcus
Subarachnoid space
between the arachnoid mater and pia mater
Lateral ventricle
is located in each cerebral hemisphere with a thin membrane, the septum pellucidum, separating the 2 ventricles anteriorly; each ventricle has an interventricular foramen that opens medially into the third ventricle
Third ventricle
is medially located between teh paired masses of the thalamus and is narrower and smaller than teh other ventricles;
Cerebral aqueduct
thin tube that connects the third ventricle to the fourth ventricle
Fourth ventricle
is located between teh pons and the cerebellum
How cerebral spinal fluid is made
CSF is made from blood plasma that leaks out of specialized, tiny blood vessels (capillaries) called the choroid plexus, and passes through the ependymal cells into 4 small brain cavities or ventricles; the ependymal cells have cilia that move the CSF in