Nervous system - Lectures 4-5 Flashcards
What are the 3 primary brain vesicles during embryonic development?
- prosencephalon (forebrain)
- mesencephalon (midbrain)
- Rhombencephalon (hindbrain)
which of the 3 primary brain besicles basically stays the same during the entire embryonic development?
- function?
mesencephalon –> becomes midbrain
- links forebrain and hindbrain
what does prosencephalon develops into? (2) –> and then 5 parts ish + functions
prosencephalon –> telencephalon & diencephalon
- telencephalon –> cerebrum = biggest part of brain (L and R hemisphere) –> coordination, memory, emotions = highest integration part
- diencephalon –> eye cup + thalamus (somatosensory + special sensory), hypothalamus (ANS, endocrine), epithalamus (pineal gland = melatonin)
what does rhombencephalon develops into?
rhombencephalon –> metencephalon + myelencephalon
- metencephalon –> pons (controls basic function of body: breathing, heartbeat, respiration) + cerebellum (behind the pons, kinda like 2nd brain)
- myelencephalon –> medulla oblongata
what 3 parts form the brain stem?
pons, midbrain and medulla oblongata
Gray matter (where + 3 charac) vs white matter (2 charac ish)
GRAY:
- cortex and nuclei in CNS
- unmyelinated nerve cell bodies
- dendrites
- axon terminals
WHITE:
- myelinated axons
- axon bundles connecting CNS regions are tracts (vs nerves in PNS) –> contain very few cell bodies
what is gyri, sulci and fissure?
- gyri (gyrus) = folds of brain –> allows to increase surface area
- sulci (sulcus) = gaps
- fissure: large sulcus between gyri –> helps us separate brain into parts
4 ways to protect the brain
- skull
- cranial meninges
- cerebrospinal fluid
- blood-brain barrier
- brain is encased in bony ______ or ________
- spinal cord runs through __________ ___________
- meninges lie between _______ and _______ to stabilize neural tissue and protect from __________
- skull or cranium
- vertebral column
- bone and tissues, protect from bruising
3 meninges + characteristics
- dura mater –> thick and tough, 2 layers ish merged together –> if open, forms cavity (venous sinus)
- arachnoid membrane –> spider web type membrane –> sits on 1 layer of connective tissue + blocks water
*Sub arachnoid space (btw arachnoid and pia mater) contains the cerebral spinal fluid in ventricules - pia mater: collé au brain tissue
how do the meninges protect brain (3)
- prevents brain from touching skull
- holds cerebrospinal fluid in
- stabilizes blood supply to and from brain
CSF:
- what is it?
- produced by what? (2)
- material selectively moves form _______ to _________
- water follows due to ______ ________
- salty solution similar to plasm
- produced by choroid plexus in ventricules
- moves from plasma to ventricules
- due to osmotic gradient
- CSF surrounds entire ________
- contained within ______A________ space
- flows from ________ to _____A_____ space to return to _______ by ______
- brain
- subarachnoid space
- ventricles to subarachnoid space to return to plasma by villi
Cerebrospinal fluid function in ______ and ______ protection
physical and chemical
how many main ventricles in brains?
- in which part of the brain are they in?
- lateral ventricles (2) in cerebrum
- third ventricle in diencephalon
(cerebral aqueduct in midbrain) - 4th ventricle in hindbrain
- what is choroid plexus?
- how is CSF produced in the choroid plexus? (3 ish)
- network of blood vessels in each ventricles in the brain
- ependymal cells (type of glial cells) produce CSF using the liquid from capillaries –> secretes liquid into ventricles which becomes CSF
- CSF goes down canal and around the meninges
how is CSF reabsorbed in the blood?
CSF reabsorbed at fingerlike projections of arachnoid membrane called villi
- 2 layers of dura mater –> space in between called veinous sinus (2) where arachnoid membrane protrudes out and forms a villus
flow of CSF from lateral ventricle to subarachnoid space (3 steps)
- lateral ventricle –> third ventricle (passes a foramen/hole)
- third ventricle –> fourth ventricle (passes through cerebral aqueduct)
- fourth ventricle –> subarachnoid space of brain and spinal cord (passes 2 foramen)
3 roles of CSF
- cushions and insulates delicate nervous tissue (ie put tofu in water so it won’t break)
- gives buoyancy to the brain (floats in CSF) –> apparent weight of 0.5kg instead of 1.5kg
- exchange of gases (O2 and CO2), nutrients and wastes (with interstitial fluid)
Blood-brain barrier
- highly __________ permeability of brain _________
- __________ foot processes promote ______ junctions between __________ cells
- protects brain from __________ water soluble compounds and __________
- small __________-soluble molecules cross BBB
- selective permeability of brain capillaries
- astrocytes –> tight junctions between endothelial cells (IMPORTANT! vs usually there is space btw endothelial cells –> pressure difference and bulk flow)
- toxic and pathogens
- lipid-soluble
3 types of cells super important for BBB + explain
- astrocyte endfoot (type of glial cells) –> send signals for endothelial cells to make tight junctions
- pericyte (not a glial cell) –> kinda like endfoot: sends signal for endothelial cells to make tight junctions
- endothelial cells make tight junction
(cells sit on basement membrane)
neural tissues has special metabolic requirements:
- neurons need a constant supply of ______A____ and _________
- brain receives ___% of blood pumped by heart
- ____A_____ passes freely/doesn’t pass across BBB
- oxygen and glucose!
- 15%
- oxygen passes freely
Glucose in brain:
- what moves it from plasma into brain interstitial fluid?
- brain responsible for how much of body’s glucose consumption?
- progressive hypoglycemia leads to (3)
- membrane transporters (glucose transporter 3)
- half!
- confusion, unconsciousness and death
spinal nerve branches into which 2 roots? + characteristics
- dorsal root
- contain afferent/sensory nuclei
- afferent neuron connect with interneurons into dorsal horns - ventral roots
- carry motor information from CNS to muscles and glands
how many pairs of spinal vs cranial nerves?
- 31 pairs of spinal nerves
- 12 pairs of cranial nerves
*Nerves = axons in PNS
Gray matter in spinal cord:
- dorsal vs lateral vs ventral horns contain what type of of nuclei?
- dorsal (back): visceral and somatic sensory nuclei
- lateral: visceral motor nuclei (sends signal to internal organs)
- ventral (front): somatic motor nuclei (to motor neurons)
white matter in spinal cord:
- divided into columns of ____A____
- ascending ___A_____ take ________ info to the brain
- descending ____A____ carry ________ signals from the brain
- ________ ____A____ stay in the cord (vs spinothalamic ____A____ go from spine to thalamus)
- tracts!
- ascending tracts take sensory info to brain
- descending tracts carry motor signals from brain
- propriospinal tracts
white/grey matter outside/inside for cerebrum vs spinal cord?
Cerebrum:
- cortex/outside = grey
- inside = white
Spinal cord:
- outside = white
- inside = grey
which region in brain is associated with body part (Dr. Penfield’s work on homunculus)?
primary somatic sensory cortex
brain stem is the ________ part of brain
- contains (3)
oldest
- contains pons, midbrain and medulla
cranial nerves can include ________ fibres, ________ fibres or both (________ nerve)
- many nuclei are associated with ________ formation (control 4)
- sensory fibres, efferent fibres or both (mixed nerves)
- reticular formation (in brain stem)–> controls wakefulness, sleep, muscle tone, pain modulation
2 things to remember for cranial nerves
1. most start from where?
2. which one do we have to remember?
- most start from the brain stem (2nd to 12th)
- Cranial nerve X (10) –> vagus, type mixed –> primary function = sensory and efferents to many internal organs, muscles and glands)
function of medulla oblongata?
medulla also includes (3)
controls involuntary functions: blood pressure, breathing, swallowing, vomiting
- somatosensory and corticospinal tracts + pyramids
what are pyramids?
- fibre carrying voluntary motor message from cerebrum to spinal cord
- where signals switch from L brain to R side of body and vice versa!
funtions of pons and midbrain
Pons:
- relay station
- coordinates control of breathing
Midbrain:
- eye movement
- relay signals for hearing and seeing reflex
Reticular formation contains lots of __________ –> which sends signals to different parts of upper brain
- reticular formation = group of _______ sending signal from _______ to _________
- nuclei
- neuron sending signal from inside to outside (?) not sure
2nd largest structure in brain?
- also called ?
- functions (5)
- sensitive to __________
- cerebellum
- little brain
1. process sensory information
2. coordinate execution of movement
3. equilibrium and balance (sensory) from somatic receptors
4. motor input from cerebrum
5. related to proprioception - sensitive to alcohol
diencephalon contains (3 ish) + functions
1. (2 fcts)
2. (3 fcts)
3. (2 parts)
- thalamus:
- relay station integrating center
- coordinates all sensory except smelling - hypothalamus
- control of homeostasis
- center of behavioural drives (hunger, thirst)
- influences autonomic function and endocrine function - endocrine structures
- pituitary gland: anterior vs posterior
- pineal gland –> produces melatonin
How can hypothalamus control well homeostasis?
no blood-brain barrier –> more sensitive to what’s going on outside!
Functions of hypothalamus (5 ish)
- control homeostasis
- activates sympathetic nervous system
- maintains body temp + osmolarity
- controls food intake
- interacts with limbic system
- …
Cerebrum (cerebroooom)
- is the site of ________ brain functions
- consists of (what? (2)) connected by what
- 2 types of matters –> inside (what consists?) or outside?
- outside matter contains (2)
- higher brain functions
- 2 hemispheres connected by corpus callosum
- grey (cortex = outside) and white matter –> mostly found on interior
- white: bundles of fibers connecting different regions of brain
GREY: - basal ganglia: control of movement
- Limbic system: link btw cognitive functions and emotions –> actually under the cerebral cortex
3 parts of the limbic system + what do they regulate?
- cingulate gyrus: emotion
- hippocampus: learning and memory
- amygdala: emotion and memory
basal ganglia
- 1 region?
- newer name?
- what does it do?
- 3 parts in each hemisphere
- basal nuclei (bc cell bodies in central nervous system VS ganglion)
- fine tune motor movement –> decides if initial signal coming from cortex is good –> if yes, sends to thalamus (?)
does the gray matter in cerebral cortex contain different layers?
yes!
what are the 4 lobes in cerebral cortex? + areas in each lobe
- Frontal lobe: controls movement
- primary motor cortex (skeletal muscle mvt)
- motor association area (skeletal muscle mvt)
- prefrontal association area - Parietal lobe:
- Primary somatic sensory cortex
- sensory association area - Occipital lobe:
- Visual cortex
- Visual association area - Temporal lobe:
- Olfactory cortex (smell)
- Auditory cortex (Hearing)
- auditory association area (hearing)
* gustatory cortex (taste) underneath cerebral cortex
difference between primary (smtg) cortex and its association area? vs prefrontal association area
- if you stimulate specific region in primary cortex, makes specific mvt/sensory = lower level
- association area: higher level –> can integrate more
*prefrontal association area: highest level of integration –> can integrate action from different lobes
Brain function:
1. sensory system (2)
2. cognitive system (1)
3. behavioral state system (1)
- monitors internal and external environments + initiates reflex response
- initiates voluntary responses –> planning, preparation and production of our own actions (ie can walk even if there’s no stimulus)
- governs sleep-wake cycles and other intrinnsic behaviors (breeding during seasons for animals)
3 functional areas in cerebral cortex
1. sensory areas (1)
2. motor areas (1)
3. association areas (2)
- sensory input translated into perception (awareness)
- direct skeletal muscle movement
- integrate information from sensory and motor areas + can direct voluntary behaviors
what is cerebral lateralization?
each hemisphere has its specialties ish (writing, math, language on L –> controls the right ish VS artistic, touch on R –> controls the L ish)
- corpus callosum links between the 2 hemispheres
what are the 3 major types of outputs from motor system of CNS?
- skeletal muscle movement (somatic motor division)
- neuroendocrine signals
- visceral responses (autonomic division –> heart, lung, stomach)
* 2 and 3 are involuntary + coordinated in the hypothalamus and adrenal medulla (brain stem)
what state system MODULATES motor output? explain
- behavioral state system!
- modulator (increase or decrease sensation) of sensory and cognitive processes
- neurons collectively known as diffuse modulatory systems (originate from reticular formation in brain stem –> projects axons to large areas of brain)
what measures brain activity?
electroencephalography (EEG)
Why do we sleep? (4)
- store memory
- remove waste from what happens during the day
- repair brain tissues
- growth hormones produced during night
what are the 4 states of sleep? which 2 are major ones?
- N1
- N2
- Slow wave sleep (N3): adjusts body without conscious commands
- rapid eye movement (REM) sleep:
- brain activity inhibits motor neurons to skeletal muscle, paralyzing them
- dreaming takes place
- knowledge consolidation for memory
- brain uses as much or more glucose than awake state
* N3 and REM are the major ones
EEG: compare amplitude and frequency
- stage W (awake, eyes closed)
- N1
- N2
- N3
- REM
- stage W similar to N1
- N2: amplitude increases, frequency decreases
- N3: decreased frequency + highest amplitude
- REM shortest frequency, amplitude btw N1/W and N2
amplitude: W = N1 < REM < N2 < N3
frequency: REM < N3 < N2 < N1 = W
order of sleep cycles?
- deepest sleep occurs in the first _____ hours
- N1 N2 N3 N2 N1 R N1 N2 N3 N2 N1 R
- N3 is the lowest, R is the highest
- 3 hours!
what is circadian rhythm?
- what control primary “clock?
- alternating daily patterns of rest and activity
- suprachiasmatic nucleus of hypothalamus –> sens axon to pineal gland –> releases melatonin
learning is the acquisition of knowledge
- associative learning vs non-associative learning
- associative learning –> links smtg to another event –> makes you learn faster
- non-associative learning –> memorize a term/textbook –> can develop habituation or sensitization
- habituation vs sensitization?
- habituation: same stimulus –> becomes less responsive (ie turn on TV while studying) –> decreased perception through inhibitory modulation (falls below perceivable threshold)
- sensitization: same stimulus: becomes more sensitive to it (ie keep doing mvt –> responds faster to it)
- where are memories stored?
- anterograde vs retrograde amnesia?
- short vs working vs long-term memory
- reflexive (implicit) vs declarative (explicit) memory
- in memory traces (in different places in brain) –> hippocampus is involved
- anterograde –> can’t remember new info VS retrograde –> can’t recall old memories
- short = few secs VS working = executing functions VS long term = store info for a long time (with consolidation)
- reflexive = how to do it + can’t really describe (riding bike) VS declarative = knowing a fact + can report verbally (Ottawa is capital)
new information goes into _____-______ memory but is lost unless _________ and stored in _____-_____ memory
- short-term
- unless processed (consolidation)
- stored in long-term memory
2 areas for integration of spoken language
- damage?
- where are the areas found in the brain?
- Wernicke’s area
- understanding language
- damage: unable to understand sensory input
- towards parietal lobe (more sensory ish) - Broca’s area
- produces speech
- damage: difficulty speaking or writing normal syntax + don’t understand complicated sentences + possible deficit in short-term memory
- towards frontal lobe (more motor ish)
