Exam 1 Vocab review Flashcards
cell soma
the cell body which contains the nucleus and synthesizes macromolecules/organelles, and integrates electrical activity
axons
nerve fibers (many branches) that carry nerve impulses away from the soma
myelin sheath CNS vs PNS
cell that speeds up the conduction of impulses on the axon of the neuron
- CNS = oligodendrocytes
- PNS = Schwann cells
synapse
the end of an axon, which comes close to another part of a different neuron and releases a neurotransmitter
neurotransmission
axon terminals release signals called neurotransmitters to other neurons at synapses
dendrites
receive synapses from axon terminals and protrude from the soma
what do astrocytes do?
- Remove and recycle neurotransmitters
- Insulate synapses from one another
- Regulate the extracellular ionic environment of the neurons
oligodendrocytes
specialized glia that form myelin in the CNS
microglia
glia that are like immune cells for the CNs and clean up after TBI
ependyma
glia that lines the ventricles
what is different about glia from nerve cells
may have processes that look like dendrites but they DON’T have an axon
CNS
the brain and spinal cord which is enclosed by bone
PNS
consists of ganglia and nerves and is not enclosed by bone
Parts of the peripheral nervous system
- sensory neurons
- motoneurons
- autonomic nervous system
Sympathetic nervous sysen
triggers fight or flight
parasympathetic nervous system
rest and recovery after sympathetic stimulation
enteric nervous system
lets the gut work and propel food
tracts
bundles of axons in the CNS
nuclei
groups of neuronal cell bodies clustered together (cortical layers)
ganglia
groups of neuronal somata in the PNs
nerves
bundles of axons in the PNS
What is white matter?
axon tracts
what is the gray matter?
soma collections
dorsal
back or top
ventral
bottom
rostral
toward the mouth
caudal
toward the tail
what are the 3 planes of sectioning?
- coronal such as splitting perpendicular to the front of the face
- horizontal such as splitting the brain into dorsal and ventral
- parasagittal, such as splitting later to the hemispheric fissure
brainstem parts
medulla oblongata
pons
midbrain
- The pontine sulcus is the groove: superior and inferior parts
diencephalon parts
thalamus and hypothalamus
telencephalon
cerebral cortex
basal ganglia => lenticular nucleus and caudate nucleus
amygdala
gyrus
bump or ridge on the surface of the brain
sulcus
groove in the surface of the brain
fissure
deep grooves in the brain
pre-central gyrus
controls movement and is more anterior
post-central gyrus
controls touch and pain
frontal lobe
motor areas and complex thinking
parietal lobe
somatosensory area
occipital lobe
visual areas
temporal lobe
auditory areas
interhemispheric fissure
splits the brain into two sides
central sulcus
divides the post and pre central gyrus as well as the frontal lobe from the parietal
development process steps
- fertilization to zygote (pronuclear stage has one from mom and one from dad)
- zygote to morula => 4-5 division cycles
- blastocyst => 2 cell layers and becomes circular and hollow (embryonic disk and bottom cubical shape)
- embryonic disk gets a primitive streak
- gastrulation (endoderm, mesoderm, ectoderm)
- Neurulation
Cell cycle phases
G1: initiates or blocks cell division
S: DNa replication
G2: proteins needed for mitosis are expressed
M: cell division
G0: the cell will not divide anymore and is not in the cell cycle
primitive streak
happens at the embryonic disk where cells are dividing and moving ventrally to the small cubical layer of cells to form a depression along the midline
- first appears at the caudal end and expands rostrally
3 layers of gastrulation and where they are in relation to one another
- endoderm is the ventral (bottom) layer
- mesoderm the middle layer
- ectoderm the dorsal (top) layer
what does the ecoderm produce
skin, CNS, and PNS
what does the mesoderm produce
bones, muscles, blood
what does the endoderm produce
lungs, liver, gut, other organs
neurulation
the flat neuro plate folds in on itself and the ridges on each side get closer until they meet along the midline
neural crest cells
produced from the neural tube closing, and these contribute to the peripheral neural system and detach from the ectoderm underneath it
anencephaly
defect in the anterior neural tube closing (the forebrain area didn’t close)
spina bifida
defect in posterior neural tube closing so that the spinal cord bulges out between vertebrae
alar plate
becomes the dorsal part of the spinal cord for sensory information
basal plate
becomes the ventral column of the spinal cord for motor axons
vesicles (3)
swellings in the neural tube that form cavity regions of CSF called ventricles
1. forebrain => prosencephalon that forms the telencephalon, diencephalon, and optic vesicle
2. midbrain => also called the mesencephalon
3. hindbrain => rhombencephalon that forms the metencephalon and myelencephalon
secondary neural vesicles
- pontine flexure which opens up to the 4th centrical between the metencephalon and the myelencephalon
-cephalic flexure between the mesencephalon and the metencephalon - cervical flexure between the spinal cord and myelencephalon
=> order goes (spinal cord area) cervical -> pontine -> cephalic (closer to diencephalon area)
ependyma
in the formation of the spinal cord, which surrounds the 4th ventricle on the dorsal side
sulcus limitans
the dop between the sensory neuron plate and the motor neuron plate
placode
thickening of the non ectoderm cells in the head
where is the PNS derived from?
the neural crest and neurogenic placodes, as well as ectoderm cells
neural crest cell divergence (table)
sensory ganglia (spinal dorsal root ganglia), autonomic ganglia (adrenal medulla, parasympathetic), schwann cells, enteric nervous system, melanocytes
neurogenic placodes cell divergence (table)
sensory ganglia (trigeminal n, facial n, vagus n, etc.), hair cells of inner ear, anterior pituitary gland, lense of the eye (outgrowth of the optic vesicle from the diencephalon where placode cells invaginate)
where are the placodes located specifically?
only in the head region => olfactory, lens, etc.
what does the neural tube develop into?
the CNS
what 3 things protects the CNS?
meninges, ventricles, and CSF
meninges layers
- dura which is tough and adheres to skull/vertebrae
- arachnoid mater which is between dura and pia and is spider like connectively
- subarachnoid space (not technically a layer but between arachnoid and pia) and can be filled with CSF components
- pia which is a single cell layer on top of the cortex
which meningeal layer has pain sensing nerves?
the dura has sensory which is where we get headaches => we also have meningeal arteries which are blood vessels
falx cerebri
dips into the interhemispheric fissure
tentorium cerebelli
separates the cerebrum and cerebellum
ventricles (4)
cavities filled with CSF
1. lateral => x2
2. 3rd
3. 4th
- cerebral aqueduct between 3rd and 4th
choroid plexus
network of blood vessels in ventricles that produce most of the CSF
what is the CSF composed of?
high sodium, low potassium, little protein, glucose, and calcium in the fluid
superior saggital sinus
major vein on the most dorsal part of the brain containing venous blood
arachnoid granulation
projection of arachnoid matter and subarachnoid space through the dura into the veins
how much CSF is produced/day?
500, but only 350 circulates and subarachnoid only holds 150 mL => the 350 gets circulated
CSF circulation flow
Choroid plexus ⇒ into 3rd ventricle which adds CSF ⇒ aqueduct no more production ⇒ 4th ventricle with more production ⇒ lateral/medial aperture/ central canal ⇒ subarachnoid space around the whole brain and spinal cord ⇒ vein ⇒ drains through arachnoid granulations
hydrocephalus
water on the brain => condition where the brain has increased pressure from CSF buildup
how much blood does the body produce per day
5000 mL of blood and the brain holds 150 mL =>750-1000 flow through per minute (20% of the blood every minute in the brain)
what is blood made of?
water, sodium, potassium, glucose, hormones, proteins, etc.
red blood cells
use hemoglobin to carry oxygen and CO2 (35-54% of blood by volume which is the hematocrit)
white blood cells
part of the immune system
platelets
cells involved in clotting
deoxygenated blood
has not made it to the lungs yet
oxygenated blood
made it to the lungs but hasn’t hit tissue yet
where does blood go into your heart?
it goes into the right atrium and then the ventricle
where does blood leave the heart from?
the left atrium and left ventricle
when blood leaves the right ventricle where does it go?
through the pulmonary ARTERY as deoxygenated blood
when blood leaves the lungs, what does it go through?
the pulmonary VEIN into the left atrium and ventricle
artery
carries blood away from the heart => high pressure
vein
carrying blood toward the heart => low pressure
what are the blood vessels form largest to smallest leaving the heart? Entering the heart from smallest to largest?
leaving: arteries, arterioles, capillaries
entering: capillaries, venules, veins, heart
capillaries: where O2 gets translated from the blood into the tissues and CO2 gets transferred back
carotid arteries (3)
- common carotid: splits your face and deep brain
- internal carotid: branch that goes to the inner brain
- external carotid arteries: a branch that goes to the outer brain
vertebral arteries
toward the side of the vertebrae and there are 2 holes on each lateral side to go through the chest and neck to foramen magnum at the base of the skull => supplies cerebellum and brianstem
circle of willis
arteries that come together as a anastomosis protecting againsted blocked arteries
- internal carotid arteries
- 3 cerebral arteries => anterior, vertebral, middle
- communicating arteries => anterior and posterior
- basilar artery => splits into two vertebral ones
dural venous sinuses
formed by two folds of dura which eventually drains into the internal jugular vein to carry blood to the heart
transverse sinus
drains the blood out of the superior sagittal sinus which is carried out laterally and drains into the internal jugular vein
jugular foramen
where the jugular and venous sinus connect at a hole leading out of the skull
hypoxia
decreased oxygen to the brain => induces vasodilation
- increased CO2 increases vasodilation
- decreased CO2 increaes vasoconstriction
what is the blood brain barrier?
tight junctions where capillary endothelium cells in the brain are also surrounded by astrocytes to only let nurtients enter and toxins exit via pumps
- lipids have an easier time passing though the barrier and may get stuck inside
circumventricular organs
the few places in the brain where the blood brain barrier does not exist
hemmrhagic stroke
bleeding in the skull arising from an aneurism in a blood vessel and can be treated by clipping the bottom of the ballooning blood vessel
ischemic stroke
a clot blocking out part of the arterial system due to the artery being blocked
- treated with a clot buster but can cause muscle weaness, difficulty speaking, drooping face, etc.
histological method
- treat the tissue with a preservative
- dissect the region of interest
- embed the tissue in peraphin/plastic to cut this section
- stain the tissue to reveal subject of interest
- examine with a microscope
axon hallock
the place at the top of the axon where there trigger for the action potential is
how many human chromosome sets are there?
23 pairs and 46 chromosomes all together
trisomy 21
down syndrome resulting from an extra 21st chromosome
nissl substance
the rough ER of cells is stained purple => neurons have dark purple stain whereas other cells are less darkly colored
what do microtubules do?
help with shape of the cell
what do intermediate filaments do?
support long processes in neurons
what do microfilaments (actin) do?
growth cones and extend the cell
kinesins
move the cargo in the anterograde direction toward the axon terminal
dyneins
move the cargo in the retrograde direction toward the cell body
types of axon transport (speeds)
- fast retrograde (50-200 mm/day) or anterograde (100-400 mm/day)
- fast anterograde for vesicles or organelles and retrograde for nerve growth factors - slow anterograde (0.25-5 mm/day)
- anterograde movement of neurofilaments required for structure
rabies
virus is taken up by peripheral nerve terminals and transported retrogradely into cell bodies of the CNS
herpes simplex
transported in sensory neurons and will survive in the soma of sensory neurons for life
CNS glia
- astrocytes for support
- oligodendrocytes to myelinate axons
- microglia as a housekeeper
PNS glia
- satellite cells to support the neurons
- schwann cellsto myelinate axons
- macrophages as housekeepers
upper motor neurons
neurons that encode information over a long distance => start in the cortex and then move downward toward the spine
major ions in the body
chloride, sodium, potassium, magnesium, calcium
ligand
a chemical that makes a pore open
initial segment
the sum of all excitatory and inhibitory inputs into the cell being monitered to stimulate the original action potential trigger in the axon
refractory period
the time span where a new action potential cannot be generated
lidocaine
drug that blocks voltage gated Na+ channels as well as action potentials => used as a local anesthetic
channelopathies
family of diseases caused by abnormal function of an ion channel usually due to a mutation in a gene for a channel protein
cable theory for axons
increasing diameter reduces resistance
babinksi sign
indicative of upper motor neuron disease as a retraction element
- goes away when it is an adult developed upper motor neuron after 4 pos-2 yrs
multiple sclerosis
antibodies attack myelin causing it to swell and detatch from the axon
glutamate
excitatory neurotransmitter in the brain
GABA
inhibitory neurotransmitter in teh brain
acetylcholine
neurotransmitter at neuromuscular junctions and other places
- enzymes break it up into choline and acetate which are taken up into the terminal by a choline transporter where it can be useful for synthesis of new transmitters
exocytosis
cell cargo is released to the external area => neurotransmitters are released to synaptic cleft
tetanus
clostridium bacteria that produce a toxin taken up by inhibitory spinal interneurons which degrades SNARE proteins for exocytosis
SNARE proteins
proteins that are along the membrane and in the vesicular membranes that interact with calcium and help release the neurotransmitters to the synaptic cleft
which neurotransmitters can be recycles through local astrocytes
glutamate and GABA
selective serotonin reuptake inhibitors
drugs for depression and anxiety are SSRIs
- lets seratonin stay longer in the synaptic cleft and activity is prolonged
ionotriphic receptor
ligand gated ion channels changed by binding of a ligand not a voltage
metabotrophic
G-protein coupled receptors which break apart and have a second messenger system that causes another channel to open
NMDA receptor
main glutamate receptor as well as a glutamate binding site where at resting potential it is blocked by magnesium, but when the neuron is partiallu depolarized to remove magnesium glutamate can initiate opening of the channel and allow Na+, Ca2+, and K+ passage
agonists
activators for neurotransmission receptors
antagonists
inhibitors of neurotransmission receptor
Ketamine
a sedative or anestheisa (antagonist) for NMDA (glutamate)
EPSPs
excitatory postsynaptic potentials that push the axon to become more depolarized (+)
IPSPs
inhibitory postsynaptic potentials that push the axon to become more hyperpolarized (-)
graded potential
amplitude varies with intensity of the stimulus and can be depolarizing or repolarizing
long term potential (LTP)
this change is long lasting after a burst of excitatory activity on a postynaptic neuron
lamina
the pieces of the bone where beneath them you find the spinal cord
dorsal roots
carry sensory information into the psinal cord on the posterior side
ventral roots
carry motor axons out of the spinal cord
spinal nerves
formed by the fusion of dorsal and ventral roots merging
ganglion
bunch of cell bodies in the PNS
vertebral column
cervival (7) => arms and hands
thoracic (12) => stomach and back
lumbar (5) => front of the legs and feet
sacral (4) => back of the legs and butt
cauda equina
the bottom of the spinal cord that is a sack of nerve roots
dermatomes
regions of the body where certain spinal nerves are innervating portions of the body
dorsal horn
has the sensory neurons
ventral horn
motor neurons
white matter regions in the spine
dorsal, lateral, and ventral funiculus
gray matter in the spine
dorsal horn, intermediate grey, and ventral horn
out of cervival, thoracic, and lumbar which has less gray matter?
thoracic has less gray matter because they innervate limbs
does rostral or caudal have more white matter?
rostral has more white matter because there are more axons going down from the brain
spinal systems
sensory and motor
sensory system
- skin => touch, vibration, temperature
- viscera => heart, lungs, gut, etc. organs
- self sensing like muscle length, load, and joint angle
somatosensory information processing
- local spinal circuits => hardwired mediated spinal reflexes preprogrammed for stimuli
- information to cerebellum and brainstem => balance and coordination of movements
- information to cerebral cortex => conscious perceptions and other responses
spinocerebellar tract
starts in the spine and then goes upward to the cerebellum
spinothalamic tract
pain and temperature and enters in the dorsal horn before crossing over and carrying up to the thalamus
dorsal column pathway
vibration and proprioception for touch which asends up the spinal cord through the dorsal funiculi and into the brainstem to the thalamus
corticospinal tract
runs down from the motor region of the cerebra cortex into the lateral funiculi area and then through the ventral horn to the biceps to contract
arthritis
pressure on a spinal nerve in a foramen which causes pain and muscle weakness