A&P Ch 12: Central Nervous System

SPC BSC 2085 Ch 12

lateral ventricles

lined with CSF; pair separated by membrane called septum pelucidum

fourth ventricle

located between the pons and the cerebellum

sulcus

a shallow depression

central sulcus

separates anterior lobe from posterior lobe

precentral gyrus

located in front of the central sulcus; beginning of the corticospinal tracts

postcentral gyrus

located behind central sulcus; pertains to sensory lobe

lateral sulcus

separates the parietal/frontal lobe from the temporal

motor areas

primary motor cortex, premotor cortex, Broca’s area, prefrontal cortex

sensory areas

primary somatosensory cortex, gustatory cortex, vestibular cortex, Wernicke’s area, primary visual cortex, auditory association area, olfactory cortex

somatotopy

all muscles of the body can be mapped out to areas of the primary cortex

association fibers

white fiber tract; gyrus to gyrus or lobe to lobe on the same side

Commissural fibers

white fiber tract; connect one hemisphere to the other. ex- corpus collosum

Projection fibers

white fiber tract; communication between the cerebral cortex and the lower spinal cord

descending

anything that ends in spinal is going to be a __ tract and vice versa

basal nuclei

Collections of cell bodies in CNS. Influence muscular activity, inhibit unnecessary movements, reguate attention and congition. Receive input from entire cerebral cortex

Diencephalon

central fore of the forebrain; includes thalamus, hypothalamus, epithalamus, and encloses the 3rd ventricle

thalamus

information is “sorted out” and “edited”, gateway to cerebral cortex; relay station

hypothalamus

controls autonomic NS, blood pressure, heart rate, satiety, and circadian rhythm

epithalamus

contains the pineal gland (secretes melatonin) and the choroid plexus

choroid plexus

structure that secretes CSF

superior colliculi

visual reflex tracking, pupillary reflex

inferior colliculi

auditor reflex, startle reflex

brainstem

Controls automatic behaviors necessary for survivial. Contains 10/12 cranial nerves; contains embedded nuclei. Made up of the midbrain, pons, and medulla

pons

connect higher brain centers and spinal cord. contains the pneumotaxic center that works with the medulla to control breathing rate

Medulla

Has cardiovascular and breathing control, contains reflex centers and choroid plexus.

periaquaductal grey matter

plays a role in pain suppression, links with he amygdala, and ANS

Substantia nigra

controls subconscious muscle activity and plays a role with dopamine production

cerebellum

provides precise timing and appropriate patterns of skeletal muscle contractions. Calculates the best way to perform a movement

limbic system

emotional/ visceral brain

amygdala

processes anger, danger, fear responses, and recognizes fearful emotions

cingulate gyrus

role in expressing emotions via gestures, and resolves mental conflict

hippocampus

convert new information into long term memories

reticular formation

governs the arousal of the brain as a whole. Keeps the cortex alert and conscious to enhance excitability. Filters out repetitive and weak stimuli

reticulospinal tract

help control skeletal muscles during coarse limb movements

cortical grey matter

localizes and interprets sensory inputs; controlled voluntary and skilled muscle activity. Functions in intellectual and emotional processing

suprachiasmatic nucleus

controls the circadian rhythms

cerebral hemispheres, diencephalon, brain stem, cerebellum

4 main parts of the brain

aphasia

the loss of language abilities due to specific areas of the brain

Broca’s area

can understand language but have difficulty speaking, writing, or using language. located in left hemisphere

Wernicke’s area

able to speak but produce a type of nonsense often referred to as “word salad,” difficulty understanding language. located in left hemisphere

short term memory

memory limited to 7 or 8 chunks of information

long term memory

memory with limitless capacity, memory bank changes continually and declines with age

memory consolidation

fitting new facts into categories of knowledge already stored in the cerebral cortex

electroencephalogram (EEG)

used to diagnose epilepsy, sleep disorders, and brain death

brain waves

electrical activity reflecting continuous activity of synaptic activity recorded

alpha waves

brain is “idling";” calm, relaxed state of wakefulness

beta waves

mentally alert, concentrating on some problem of visual stimulus

theta waves

common in children; uncommon in awake adults but may occur when concentrating

delta waves

indicates deep sleep, reticular activating system is suppressed. also indicates brain damage in awake individuals

REM

sleep stage in which the skeletal muscles are inhibited, most dreaming occurs

Stage N1

sleep stage in which relaxation begins, EEG shows low-amplitude mixed frequency and alpha waves, arousal is easy

Stage N2

sleep stage in which arousal is more difficult; irregular EEG with sleep spindles

Stage N3

sleep stage in which EEG has high- amplitude theta and delta waves; vital signs decline, arousal is difficult; bed wetting, night terrors, and sleepwalking may occur

meninges

three protective, membranous layers that encase the brain and spinal cord

dura mater

tough, leathery strong meninx

arachnoid

middle meninx that forms loose brain covering

subarachnoid space

filled with CSF, large blood vessels

Pia mater

delicate connective tissue that clings tightly to brain

CSF

forms liquid cushion that gives buoyancy to CNS organs and prevents the brain from crushing under its own weight.

blood brain barrier

helps maintain stable environment in the brain; has a selective barrier

concussion

alteration in Brian function following below to the head

contusion

concussion leading to bruising of the brain or permanent damage

cerebral edema

swelling of the brain

CTE

progressive neurodegeneration due to repeated head trauma; memory impairment, concentration loss, poor judgement and impulse control, apathy, irritability, and hopeflessness, aggression, depression and suicide

Ischemic stroke

Caused when blood circulation to the brain and brain tissue dies

hemorrhagic stroke

blood vessel in the brain breaks and bleeds

transient ischemic attacks

temporary episodes of reversible cerebral ischemia lasting less than 5 minutes

Alzheimers disease

progressive degenerative disease of the brain that results in dementia

Parkinson’s disease

degeneration of the substantia nigra, lack of dopamine results in too little movement

Huntington’s disease

fatal hereditary disorder caused by accumulation of the mutant protein that leads to degeneration of basal nuclei and results in too much movement

plexus

group of nerves

31

how many pairs of spinal nerves are there

cervical enlargement

contains cervical and brachial plexus with nerves that continue down upper limb

lumbar enlargement

contains lumbar and sacral plexus with nerves that continue down the lower limb

conus medullaris

tapered, lower end of the spinal cord, located at L1or L2

cauda equina

collection of nerve roots at the inferior end of the cerebral canal

filum terminale

fibrous extension of the pia mater; anchors the spinal cord to the coccyx