LSUE BIO1160 Hamlin Chapter 14 Exam 3 (Brain)

Rostral

toward the forehead

Caudal

toward the spinal cord

Forebrain

prosencephalon

Midbrain

mesencephalon

Hindbrain

rhombencephalon

Cerebrum

largest part of forebrain; 83% of brain volume

Cerebral hemispheres

pair of half globes of cerebrum

Gyri

thick folds on cerebrum surface

Sulci

shallow grooves between gyri

Longitudinal cerebral fissure

deep groove that separates cerebral hemispheres

Corpus callosum

thick nerve bundle at bottom of longitudinal fissure that connects hemispheres

Cerebellum

second-largest part of brain

Brainstem

the rest of the brain

Tracts

bundles of nerve fibers (axons)

Cortex

surface layer of gray matter in cerebrum, cerebellum

Nuclei

deeper masses of gray matter, surrounded by white matter

Neurulation

occurs within first 3 weeks

Meninges

three membranes surrounding brain and spinal cord

Dural sinuses

spaces located where periosteal and meningeal layers separate

Superior sagittal sinus

just under calvaria along median line

Transverse sinus

runs horizontally from rear of head toward each ear

Third ventricle

narrow medial space beneath corpus callosum

Fourth ventricle

small triangular chamber between pons and cerebellum

Interventricular foramen

pore that connects lateral ventricles to third ventricle

Cerebral aqueduct

tube running through midbrain that connects third ventricle to fourth ventricle

Central canal

tube that connects to fourth ventricle and runs through center of spinal cord

Cerebrospinal fluid (CSF)

clear, colorless liquid that fills the ventricles, canals of CNS and bathes its external surface

Brain barrier system (BBS)

regulates what substances can get from bloodstream into tissue fluid of the brain

Blood-brain barrier

protects the brain at the blood capillaries

Blood-CSF barrier

protects the brain at the choroid plexus

Circumventricular organs (CVOs)

locations where the barrier is absent

Stroke (cerebral vascular accident, CVA)

sudden death of brain tissue due to interruption of blood supply

Medulla oblongata

adult brain region that develops from embryonic myelencephalon

Pyramids

ridges on anterior surface, resemble side-by-side baseball bats

Olives

prominent bulges lateral to each pyramid

Gracile and cuneate fasciculi

of spinal cord continue as two pairs of ridges on posterior medulla

Medial lemniscus

axons of gracile and cuneate nuclei decussate and form ascending (sensory) tract to thalamus

Corticospinal tracts

descending motor tracts in pyramids; carry signals down to skeletal muscles

Inferior olivary nucleus

relay center for signals to cerebellum

Reticular formation

loose network of nuclei extending through entire brainstem

Cerebellar peduncles

thick stalks on posterior pons that connect it (and the midbrain) to the cerebellum