Chapter 15: Brain and Cranial Nerves

premotor cortex

(somatomotor association area) coordinating learned, skilled motor activities

cranial nerves

- 12 pairs - serve head and neck (except vagus/ CN X) - sensory nerves - motor nerves - mixed nerves

O.O.O.T.T.A.F.V.G.V.A.H

- Oh - Once - One - Takes - The - Anatomy - Final - Very - Good - Vacations - Are - Had

cranial nerve VI

- abducens - sensory function: none - somatic motor function: 1 extrinsic eye muscle

cranial nerve XI

- accessory - sensory function: none - somatic motor function: 2 body muscles

pons

- anterior, middle portion of brainstem - sensory and motor tracts connecting brain to spinal cord - autonomic functions

pia mater

- areolar CT - form-fitting - inner, soft, tender layer

brainstem

- autonomic functions - mesencephalon - pons - medulla oblongata - connects cerebrum, diencephalon, and cerebellum to spinal cord

blood brain barrier

- blood and neurons separate - astrocytes and blood capillaries - helps prevent neuron exposure to harmful substances (drugs, wastes, fluctuating concentrations)

midbrain parts

- cerebral peduncles - superior/inferior colliculi

cerebellum

- comprises 10% of brain - part of metencephalon - responsible for coordinating and fine tuning movements, planning/executing movements, agility, balance and posture, adjusts/regulates movements (smoothness)

cerebrum

- comprises 85% of brain - responsible for human's conscious thought processes and complex intellectual functions - intelligence and reasoning - thought, memory, judgement - voluntary motor, visual, auditory

hypothalamus

- control autonomic nervous system - control endocrine system - regulate body temperature - emotional behavior (part of limbic system) - regulate hunger and thirst - regulation of sleep/wake cycle (circadian rhythms)

dura mater

- dense irregular CT - periosteal layer - meningeal layer (dural venous sinus) - hard outer layer

meninges

- dura mater - arachnoid mater - pia mater

cranial nerve VII

- facial - sensory function: taste from anterior 2/3 of tongue - somatic motor function: muscles of facial expression

cerebrum lobes

- frontal - parietal - occipital - temporal - insula

cranial nerve IX

- glossopharyngeal - sensory function: touch and taste posterior 1/3 of tongue - somatic motor function: one pharyngeal muscles

nervous tissue organization

- gray matter - whiter matter

cranial nerve XII

- hypoglossal - sensory function: none - somatic motor function: muscles of tongue

medulla oblongota

- inferior portion of brainstem - continuous with spinal cord inferiorly - sensory and motor tracts connecting brain to spinal cord - autonomic functions -decussation of the pyramids (motor fibers crossover = contralateralization)

ventricles

- lateral ventricles - third ventricle - fourth ventricle *cavities filled with CSF

cerebrum parts

- longitudinal fissure - gyri - sulci

mesencephalon develops into

- mesencephalon

rhombencephalon develops into

- metencephalon - myelencephalon - spinal cord

pons parts

- middle cerebella peduncles - autonomic respiratory centers - superior olivary complex

functional areas of cerebrum

- motor - sensory - association

white matter

- myelinated axons - tracts = bundles

gray matter

- neuron cell bodies, dendrites, unmyelinated axons - cortex = superficial layer - nuclei = close to surface or deep within brain

cranial nerve III

- oculomotor - sensory function: none - somatic motor function: 4 extrinsic eye muscles

cranial nerve I

- olfactory - sensory function: olfaction - somatic motor function: none

cranial nerve II

- optic - sensory function: vision - somatic motor function: none

epithalamus

- pineal gland - endocrine gland secretes melatonin - regulates circadian rhythm

association area parts

- premotor cortex - somatosensory association area - visual association area - auditory association area * no separate association areas for olfactory and gustatory

motor area parts

- primary motor cortex - frontal eye field - motor speech area (broca area)

sensory area parts

- primary somatosensory cortex - primary visual cortex - primary auditory cortex - primary olfactory cortex - primary gustatory cortex

choroid plexus

- produces CSF - ependymal cells and capillaries - in each ventricle - drains into arachnoid villi and into dural venous sinous

initial development of brain and spinal cord

- prosencephalon - mesencephalon - rhombencephalon

thalamus

- receives conscious senses (except olfaction) - filters and relays to primary cortices and association areas

medulla oblongota important autonomic centers

- regulate heart rate and strength - controls blood pressure (arteriole control) - respiratory rate (along with pons) - centers controlling coughing, sneezing, salivating, swallowing, gagging, vomiting, and hiccupping

forms of brain protection

- skull (bones) - meninges - cerebrospinal fluid - blood brain barrier

parts in midbrain only seen in cross sections

- substantia nigra - dopamine - motor control, emotion, pleasure, pain, compulsion - degeneration = parkinson's

midbrain

- superior portion of brainstem - sensory and motor tracts connecting brain to spinal cord - autonomic functions

prosencephalon develops into

- telencephalon - diencephalon

cranial nerve V

- trigeminal - sensory function: general sensory from surface of head and mouth, including touch from anterior 2/3 of tongue - somatic motor function: muscles of mastication and others

cranial nerve IV

- trochlear - sensory function: none - somatic motor function: 1 extrinsic eye muscle

cranial nerve X

- vagus - sensory function: visceral sensory most organs - somatic motor function: most pharyngeal and laryngeal muscles

cerebrospinal fluid (CSF) location and function

- ventricles and subarachnoid space - cushioning - buoyancy - transport of nutrients and waste

cranial nerve VIII

- vestibulocochlear - sensory function: hearing and equilibrium - somatic motor function: none

arachnoid mater

- web of collagen and elastic fibers (trabeculae) - subarachnoid space (cerebral spinal fluid) - middle layer

corpus callosum

a broad band of nerve fibers joining the two hemispheres of the brain.

inferior colliculi

auditory reflex centers

fourth ventricle

between brainstem and cerebellum

lateral ventricle

cerebrum

telencephalon becomes

cerebrum

projection tracts

cerebrum to the lower brain structures - decussate = contralateralization

visual association area

color, movement, form, facial recognition

association tracts

connect different regions of the cerebral cortex within the same hemisphere - arcuate fibers - longitudinal fasiculi

middle cerebellar peduncles

connects pons to cerebellum

motor areas

control voluntary motor functions

auditory association area

correlates with memories of sound, including music

cerebral peduncles

descending motor axons

third ventricle

diencephalon

sulci

grooves of brain

diencephalon becomes

hypothalamus, thalamus, epithalamus (including pineal gland)

primary gustatory cortex

insula, taste info from taste buds

gnostic area

integrates all sensory input into coherent whole by working with association areas within parietal, occipital, and temporal lobes to produce comprehensive understanding of current activity; composed of parts of parietal and temporal lobes

superior olivary complex

involved in sound localization

sensory areas

involved with conscious awareness of sensation

temporal lobe

language, emotion, smell, olfactory, auditory

commissural tracts

left and right hemispheres - corpus callosum

longitudinal fasiculi

long tracts connecting different lobes

myelencephalon becomes

medulla oblongata

insula

memory, gustatory (sense of taste)

mesencephalon becomes

midbrain (superior and inferior colliculi and cerebral aqueduct)

frontal eye field

muscles for eye movement, reading and coordinating binocular vision

motor speech area (broca area)

muscles used in speech, usually left front lobe only

primary visual cortex

occipital lobe, visual info from eye

frontal lobe

planning, judgement, decision making, impulse control, attention, personality, motor control

metencephalon becomes

pons, cerebellum

primary somatosensory cortex

postcentral gyrus, general sensory info

primary motor cortex

precentral gyrus, voluntary contralateral skeletal muscles

precentral gyrus

primary somatic motor cortex (frontal lobe)

postcentral cyrus

primary somatosensory cortex (parietal lobe)

association areas

process and interpret sensory input and/or coordinate motor output

wernicke area

recognizing, understanding spoken and written language; composed of parts of parietal and temporal lobes, works with other areas to speak, type and write

autonomic respiratory centers

regulate rate and depth of breathing

gyri

ridges of brain

parietal lobe

sensory information helps understand position in environment, general sensory

central sulcus

separates frontal and parietal lobes

longitudinal fissure

separates left and right hemispheres

arcuate fibers

short tracts within same lobe

spinal cord becomes

spinal cord

primary auditory cortex

temporal lobe, auditory info from inner ear

primary olfactory cortex

temporal lobe, olfactory info from nasal cavities

somatosensory association area

understanding of object producing the stimulus

occipital lobe

visual input, visual memories

superior colliculi

visual reflex centers