Central Nervous System Flashcards
Describe the embryologic origins (primary germ layers) of the brain, beginning with formation of the neural
plate
step 1.) 3rd week - ectoderm thickens and forms neuroplate
and it invaginate, forming the neural groove (surrounded by folds) these folds fuse and develop into the neurotube
some if the folds pinch off and develop the neural crest (which makes the PNS)
neural crest - somites - dermis, muscles and skeleton
- The neural tube - neural tube differentiates into the brain and spinal cord
From what primary germ layer does all nervous tissue originate?
ectoderm
Identify the adult brain structures associated with each of the three primary brain vesicles.
Prosencephalon (forebrain)
Mesencephalon (midbrain)
Rhombencephalon (hindbrain)
What single factor can prevent most cases of neural tube defects?
taking folic acid
What are the 3 structural outcomes of the fact that the brain develops within a restricted
space?
1.) surface convolution
sulci - depressions
gyri - elevations and sulci goes between them
Increase surface area so more neurons can pack in and more impulses come through
- ) the way it grows, cerebral hemispheres grow posteriorly and laterally
- ) midbrain and cervical flexures (bending and curves)
What does gray matter comprise? white matter?
gray matter - makes cerebral cortex , short, nonmyelinated axons and neuron cell bodies
white matter - bundles of nerve fibers (tracts) in cns, myelinated
What is meant by the term hemispheric (or cerebral) lateralization? by the term cerebral
dominance?
laterialization - two distinct hemispheres of the brain
dominance - one hemisphere is dominant for language over another (most people are left hemisphere dominant for language, math, etc while right is more abstract thought)
Identify and describe the two most common types of neural tube defects.
- Anencephaly - failure to close ANTERIOR neural tube
2. Spina Bifida - failure to close of the POSTERIOR neural tube
What is the septum pellucidum?
A thin membrane located at the midline of the brain between the two cerebral hemispheres (lateral ventricles)
Name the five lobes of the cerebrum and identify the sulci or fissures that separate one
lobe from another.
Frontal lobe
- Precentral gyrus
- Centeral sulcus
- Postcentral gyrus
Parietal lobe
- Pareto-occipital sulcus
Occipital lobe
-Transverse cerebral fissure
Cerebellum
From partial lobe to temporal lobe theres the lateral sulcus
What is the general function of each of the following cortical areas?
Motor Area’s:
- primary motor cortex - premotor cortex
- Broca’s area (the motor speech area)
- Wernicke’s area
- frontal eye field
Primary motor cortex - Located in the precentral gyrus in the frontal lobe
- contains pyramidal cells which create tracts
Controls voluntary contractions on the opposite side of the body
Premotor movement- Anterior to precentral gyrus in the frontal lobe
- involved in planning movements and in controlling learned, skilled movements
Broca’s area - above lateral sulcus
- functions thoughts to speech
Damage: non fluent aphasia ( when you know what you want to say but cant say it)
Wernicke’s area - posterior part of the left temporal lobe
- involved in comprehension of language (speech and written)
Frontal eye field - located in the frontal lobe
- controls voluntary scanning movement of the eye
Test: Tract by asking patient to read and tract eye movement
What is the general function of each of the following cortical areas?
primary somatosensory cortex somatosensory association area primary visual cortex visual association area olfactory cortex gustatory cortex vestibular cortex visceral sensory area affective language area
- ) primary somatosensory cortex - in postcentral gyrus of each parietal lobe
* receives sensory stimuli from the opposite (contralateral) side of the body
* capable of spatial discrimination (being able to identify what part of the body is stimulated) - ) somatosensory association area -
- ) primary visual cortex
- ) visual association area 5.) olfactory cortex
- ) gustatory cortex
- ) vestibular cortex
- ) visceral sensory area
What is the general function of each of the following cortical areas?
sensory areas:
primary somatosensory cortex somatosensory association area primary visual cortex visual association area olfactory cortex gustatory cortex vestibular cortex visceral sensory area affective language area
- ) primary somatosensory cortex - in postcentral gyrus of each parietal lobe
* receives sensory stimuli from the opposite (contralateral) side of the body
* capable of spatial discrimination (being able to identify what part of the body is stimulated) - ) somatosensory association area - posterior to primary somatosensory cortex
* functions in integrating & interpreting sensory inputs (touch sensations)
3.) primary visual cortex -
extreme posterior tip of occipital lobe at calcimine sulcus
* receives sensory input regarding shape, color , and movement
4.) visual association area- surrounds primary visual cortex in the occipital lobe
*recieves input from the primary visual cortex & the thalamus
TEST: Ask patient to identify object. Eraser —-rubber (incorrect)
- ) primary auditory cortex - located in superior part of temporal lobe, near lateral central sulcus
* receives input from cochlea (hearing part of inner ear) - ) auditory association area- inferior and posterior to the primary auditory cortex
* involved in perception/interpretion of sound (retains memory or sounds and meanings of speech)
5.) olfactory cortex - located in medial aspect of temperol lobe
*recieves input related to smell and acknowledges orders
TEST: smell associated with emotions
- ) gustatory cortex - located above lateral cerebral sulcus
* taste stimuli are recieved (sweet, salty, butter etc) - ) vestibular cortex- located in the posterior insult
* involved in awareness of balance - ) visceral sensory area
* involved in conscious perception of visceral sensation
What is the general function of each of the following cortical areas?
Multimodel association areas (send output to premotor cortex):
anterior association area/prefrontal cortex
posterior association area
limbic association area
anterior association areas/ prefrontal cortex -
involved with intellect, judgement, and personality. sets mood and emotions
posterior association area-
different in L and R cerebral hemisphere
- affective language thought to be in the L hemisphere
limbic association area
in cerebrum and diencephalon
- emotional brain -
What is the reticular formation? Where is it located?
-Maintains cerebral cortical alertness (reticular activation system)
- Filters out repetitive stimuli
- Helps regulate skeletal and visceral muscle activity
what is memory?
the storage and retrieval of information
Identify and describe the main categories of long-term memory
declarative memory (fact), procedural memory (skills), motor memory, and emotional memory
Identify the stages of declarative memory and describe the characteristics of each.
short term and long term memory
Short-term memory allows you to remember small chunks of info to use and never remember again. Long-term memory allows us to store a lot of information in our memory bank to retrieve later
Identify the factors that can influence memory consolidation (i.e., transfer from STM → LTM) and describe their effect.
- Emotional state -
We learn best when we are alert, motivated, surprised, or aroused. Neorepinephrine is a transmitter - Rehearsal - rehearsing or repeating material enhances memory
- Association - associating new information with old memories
- Automatic memory- automatically tracking something subconsciously (when some words stick with you)
Identify and contrast the four frequency classes of brain wave seen in an EEG.
Alpha waves (awake but relaxed) 8-13 Hz
Beta waves - (awake, alert)
(14-30 Hz)
Theta waves (common in children)
Delta waves (deep sleep)
Alpha waves: 8-13 Hz, regular, low amplitude, synchronous, indicate brain is relaxed and wakeful
Beta waves: 14-30 Hz, less regular, higher frequency, occur when mentally alert and concentrating
Theta waves: 4-7 Hz, more irregular, common in children, may appear in adults when concentrating
Delta waves: 4> Hz, high amplitude, seen when asleep or under anesthesia (when RAS is suppresses), indicates brain damage in awake adults
What is the primary EEG wave form during periods when an adult is alert and concentrating and problem-solving? when one is alert and relaxed? during deep sleep?
beta; alpha; delta
What is sleep?
a state of partial unconsciousness from which a person can be aroused by stimulation
What are the two main types of sleep?
Non-rapid eye movement (NREM)
Rapid eye movement (REM)
Identify and describe the characteristics of each of the stages of non-rapid eye movement (NREM) sleep. Be sure to include mention of typical EEG patterns and general physiological characteristics in your descriptions.
Stage 1: Relaxation; alpha waves; easy to arouse
Stage 2: Irregular EEG with sleep spindles; arousal is more difficult
Stage 3: Theta and delta waves; vital signs decline
Stage 4: Dominated by delta waves; arousal is difficult; bedwetting, night terrors, and sleep walking may occur
Describe the characteristics of rapid eye movement sleep, including mention of typical EEG pattern and general physiological characteristics in your description.
alpha waves, skeletal muscles actively inhibited, most dreaming occurs
