APK2100c - Ch. 13: The Central Nervous System

rostral

towards the nasal region or higher brain centers

caudal

toward the tail or inferior portion of the trunk

cerebrum

the largest part of the brain; had right and left hemispheres

diencephalon

brain region that gives rise to thalamus, hypothalamus, and epithalamus

cerebellum

second largest part of the brain

brain stem

rostral continuation of the spinal cord; consists of medulla oblongata, pons, and midbrain

prosencephalon (forebrain)

primary brain vesicle that gives rise to the cerebrum and diencephalon

Mesencephalon (midbrain)

primary brain vesicle that gives rise to the midbrain of the brain stem

Rhombencephalon (hindbrain)

primary brain vesicle that gives rise to the cerebellum, pons, and medulla oblongata

ventricles

fluid-filled cavities of the brain that are continuous with each other and the central canal

ciliated ependymal cells

line the brain ventricles and help circulate CSF

lateral (first and second) ventricles

ventricles located in the cerebral hemispheres; separated by the septum pellucidum anteriorly

third ventricle

ventricle located in the diencephalon; connects to each lateral ventricle via an interventricular foramen

interventricular foramen

connection between lateral ventricles and third ventricle

cerebral aqueduct

connects the third and fourth ventricles

fourth ventricle

ventricle located in the brain stem; dorsal to the pons and superior half of the medulla oblongata

lateral apertures

pair of openings from the fourth ventricle to the subarachnoid space on either side and between the medulla and cerebellum

median aperture

opening in the roof of the fourth ventricle that connects to the subarachnoid space

central canal

a fluid-filled channel in the center of the spinal cord; connects to brain via fourth ventricle

cerebellar cortex

layer of gray matter surrounding the cerebellum

cerebral cortex

outer region of the cerebrum, containing sheets of nerve cells; gray matter

brain nuclei

groups of neuron cell bodies that form gray portions of gray matter in the CNS

medulla oblongata

most caudal part of brain stem

pyramids (of medulla oblongata)

ridges flanking the ventral line of the medulla oblongata; play a large role in carrying voluntary motor output to the spinal cord

decussation (of the pyramids)

crossover points of the corticospinal tracts; because of this, each cerebral hemisphere controls the voluntary movements of the opposite side of the body

olive (of medulla oblongata)

lateral enlargements of the medulla oblongata that contain inferior olivary nuclei

inferior olivary nucleus

relay center for proprioceptive information to cerebellum

relay nuclei

nuclei in the brain whose neurons receive signals from one region of the central nervous system and send this information to another region

inferior cerebellar peduncles

connect medulla oblongata to cerebellum

nucleus gracilis

medullary relay nucleus at which first-order neurons of the dorsal column system synapse specifically from the lower body and legs

nucleus cuneatus

medullary relay nucleus at which first-order neurons of the dorsal column system synapse specifically from the upper body and arms

reticular formation

cluster of brain nuclei running through the core of the brainstem that includes the raphe nuclei, medial nuclear group, and lateral nuclear group; important nuclei within these groups include the cardiac center, vasomotor center, and medullary respiratory center

pons

ventral bridge between the brain stem and cerebellum

pontine nuclei

relay brain nuclei in a path that connects a portion of the cerebral cortex with the cerebellum involved with coordination of voluntary movements

middle cerebellar peduncle

contains transverse axons connecting pons to cerebellum

tectum

the dorsal part of the midbrain (dorsal to cerebral aqueduct)

superior cerebellar peduncles

contain axons that extend from the cerebellum to the red nuclei of the midbrain

substantia nigra

a brainstem structure that innervates the basal ganglia and is a major source of dopaminergic projections; degeneration of these neurons is the cause of Parkinson's disease

red nucleus

large pigmented nucleus of the midbrain that receives inputs from the cerebellum and motor cortex and sends axons to motor neurons in the spinal cord; involved in limb flexion

periaqueductal gray matter

the region of the midbrain surrounding the cerebral aqueduct; contains neural circuits involved "fight-or-flight" reaction and responses to visceral pain (e.g. nausea)

cerebral peduncles

two bulging structures of the midbrain that contain descending pyramidal motor tracts

vermis

connects the two cerebellar hemispheres

folia

folds of the cerebellum

anterior lobe (of cerebellum)

ID the yellow in photo

posterior lobe (of cerebellum)

ID the blue in photo

flocculonodular lobe

ID the green in photo

arbor vitae

white matter of the cerebellum; "tree of life"

deep cerebellar nuclei

nuclei located within the cerebellar hemispheres; receive projections from the cerebellar cortex and send projections out of the cerebellum to other parts of the brain

motor cortex

communication between the cerebellum and _______ _______ helps smooth out body movements, and allows for motor memory

same; ipsilateral

injury to one side of the cerebellum affects the (same/different) side of the body; all fibers that enter and leave the cerebellum are ____________.

thalamus

egg-shaped mass of gray matter in the diencephalon of the brain; consists of nuclei through which information is relayed to the cerebral cortex

interthalamic adhesion

small midline connection joining the right and left parts of the thalamus

cerebral cortex

thalamic nuclei organize and then either amplify or minimize signals headed to the _______________

hypothalamus

inferior region of the diencephalon; visceral control center of the brain

optic chiasma

cross-shaped structure anterior to the diencephalon of the brain, representing the point of crossover of half the axons of the optic nerve

pituitary gland

projects inferiorly from the hypothalamus

mammillary bodies (of hypothalamus)

a protrusion of the bottom of the brain at the posterior end of the hypothalamus, containing some hypothalamic nuclei; part of the limbic system

infundibulum

stalk that attaches the pituitary gland to the hypothalamus.

homeostasis

the hypothalamus regulates most activities of ___________________; including control of autonomic nervous system, body temperature, hunger/thirst; sleep-wake cycles, endocrine system (via pituitary gland), emotional responses, motivational behavior, and memory formation

epithalamus

contains pineal gland which secretes melatonin, and posterior commissure

melatonin

the pineal gland, located in the epithalamus, secretes...

transverse cerebral fissure

separates cerebral hemispheres from cerebellum inferiorly

longitudinal fissure

separates right and left cerebral hemispheres

sulcus

shallow groove on the surface of the cerebrum

gyrus

twisted ridges of brain tissue located between sulci

frontal lobe

parietal lobe

occipital lobe

temporal lobe

insula

regions of cortex located at the junction of the frontal and temporal lobes

central sulcus

separates frontal and parietal lobes

precentral gyrus

contains the primary motor cortex

parieto-occipital sulcus

separates parietal and occipital lobes

lateral sulcus

separates temporal lobe from parietal and frontal lobes

postcentral gyrus

contains primary somatosensory cortex

sensory homunculus

map showing the amount of sensory cortex devoted to each body region; amount of cortex devoted to body region is related to sensitivity (number of receptors) in that region

primary visual cortex

the region of the posterior occipital lobe whose primary input is from the retina of the eye

primary auditory cortex

the region of the superior temporal lobe whose primary input is from the auditory system

commissural fibers

horizontal fibers that connect gray matter of two hemispheres (1)

corpus callosum

largest band of commissural fibers in the brain

association fibers

short or long fibers that connect different parts of the same brain hemisphere (2)

projection fibers

vertical fibers that connect the cerebral cortex to more caudal parts of the CNS (3)

internal capsule

compact bundle of projection fibers which passes between the thalamus and the basal nuclei

corona radiata

projection fibers that fan out to and from the cerebral cortex

basal nuclei (ganglia)

group of subcortical brain nuclei that cooperate with the cerebral cortex to start, stop, and regulate the intensity of voluntary movements

basal forebrain nuclei

degeneration is associated with Alzheimer's; part of the basal forebrain cholinergic system

dura mater

Most external and toughest of the three membranes (meninges) covering the brain and spinal cord

arachnoid mater

weblike middle layer of the three meninges

pia mater

thin, delicate inner membrane of the meninges

periosteum

the most superficial layer of the duramater is actually

dural venous sinuses

the two layers of the dura mater separate to form....

dural venous sinuses

collect venous blood from the brain and direct it into the internal jugular veins of the neck

falx cerebri

large, sickle-shaped, vertical sheet of meningeal dura mater that lies in the longitudinal fissure between cerebral hemispheres

falx cerebelli

vertical sheet of meningeal dura mater that runs along the vermis of cerebellum in the posterior cranial fossa

tentorium cerebelli

peri horizontal sheet of meningeal dura mater that lies in the transverse fissure between the cerebrum and cerebellum

arachnoid granulations

knoblike projections of the arachnoid mater that extend from the subarachnoid space into the superior sagittal sinus that allow CSF to pass from the subarachnoid space into the dural venous sinuses

buoyancy, resist compressive forces, nourishment, waste removal, and chemical transport

(5) functions of CSF

choroid plexus

capillary-rich membrane on the roof of the brain that forms CSF; consists of pia mater and ependymal cells

sensory and motor innervation of entire body inferior to head, two-way conduction pathway between body and brain, integration center for reflexes

(3) major functions of spinal cord

conus medullaris

tapered end of spinal cord; around L1 - L2 in most people