Lectures 6-7 : Anatomy Flashcards
what is decussation?
axons crossing the midline
contra-lateral?
same side of body
ipsilateral?
same side of body
dorsal vs. ventral
rostral vs. caudal
dorsal/superior = back/ back of spine
ventral/inferior = belly/ front of spine
rostral/anterior = nose
caudal/posterior= tail
what is different about how directions are applied to humans?
ends with ior?
directions are perpendicular or parallel to the ground
ends with al?
directions relative to neuraxis
what is the neuraxis?
axis defined by the embryonic neural tube
horizontal vs. sagital vs. frontal?
what does transverse mean?
perpendicular to the neuraxis
somatic vs. visceral/ autonomic
somatic
- motor axons control muscle contractions
- sensory nerves entering spine containing info from skin, muscles, and joints
visceral/autonomic
- innervates internal organs, blood vessels and glands
- motor axons control relaxation or contraction of walls of blood vessels and intestines
- sensory axons carry info on visceral function
- divided into sympathetic and para sympathetic
afferent vs. efferent?
afferent fibers = arrive into the central nervous system
ex. sensory axons carrying information from fingertips into the dorsal root of the spine
efferent fibers = exit the central nervous system
ex. motor axon exiting the ventral rot of the spine to control fingertips
where are the soma and axons concerning the somatic nervous system?
CNS - soma
PNS - axons
cerebrum - desc, direction, size?
- soft, sensory fibers, perception, memory
- the rostral-most and largest part of the brain is the
what divides the cerebrum?
- cerebral hemispheres
- separated by the deep sagittal fissures
what do the hemispheres of cerebrum control?
left hem - right side of body
right hem - left side of body
cerebellum?
- little brain
- movement control center
- has extensive connections with the cerebrum and the spinal cord
what do the sides of the cerebellum contain?
left - left side of body
right - right side of body
white matter- surround?
mostly axons
at bottom - surrounds gray
grey matter?
mostly cell bodies
at top - surrounds white
brain stem?
- a complex nexus of fibers and cells
- relay information from the cerebrum to the spinal cord and cerebellum, and vice versa
- site where vital functions are regulated, such as breathing, consciousness, and the control of body temperature
- one can survive damage to the cerebrum and cerebellum, but damage to the brain stem is usually fatal.
spinal nerve function?
- how the spinal cord communicates with the body
composition of the spinal nerve?
- dorsal root = afferent (into spine)
- ventral root = efferent (out of spine)
how many spinal nerves per each level of the spinal cord?
1
what is the dorsal root ganglia?
contains the cell bodies of sensory neurons but there are no ventral root ganglia
what are the parts of the spinal cord from a horizontal view?
grey matter
- dorsal horn
- intermediate zone
- ventral horn
white matter
- dorsal column
- lateral column
- ventral column
what is the menix?
the three membranes that cover the surface of the central nervous system
what are the parts of the meninges?
dura mater - tough protectant
arachnoid membrane - web like
pia mater - surface grooves
- many blood vessles
- adheres closely to surface of the brain
what is the subdural space?
space between dura matter and arachnoid membrane
when blood vessels passing through dura burst -> subdural hematoma
what is the subarachnoid space?
- filled with salty clear liquid called cerebrospinal fluid
- has negative pressure so that the membranes can suction
what is cerebrospinal fluid?
- CNS
- fluid produced by the choroid plexus - - flows through the ventricular system to the subarachnoid space
what is the ventricular system?
- made of the fluid-filled caverns and canals inside the brain
what is the ventricular system?
- made of the fluid-filled caverns and canals inside the brain
arachnoid villi?
special structures in the subarachnoid space that allow CSF to be absorbed by the blood vessels
what are the divisions of the spine, how many segments does each division have?
4 segments of spinal cord nerves
- cervical = 8 segments (arm)
- thoracic = 12 segments
- lumbar = 5 segments (leg)
- sacral = 5 segments
CTLS
what is the caudal aquina?
spinal nerves from lumbar and sacral segments
what are the lobes of the brain? what do they correlate with?
- frontal - motor
- parietal - touch
- temporal - auditory
- occipital - visual
what is the brain stem made of?
- pons
- medulla
- midbrain
insula location and function?
- lays behind temporal lobe
- taste
why do gyri and sulci exist?
maximize brain surface area
what is the important sulcus and gyri?
central sulcus
- separates the frontal lobe and parietal lobe
pre-central gyrus
- rostral to central sulcus
postcentral gyrus
- immediately caudal to the central sulcus
what are the important fissures?
lateral/sylvian fissure
- seperates temproal lobe from frontal and parietal lobes
superior temporal gyrus
- superior part of the temporal lobe and borders sylvian fissure
what is the infection of the meningies?
meningitis
neural tube development - what makes up the embryo?
endoderm: innermost = internal organ lining
mesoderm: middle = middle layer of cells that develop into bones and muscle
ectoderm: outer layer = nervous system and skin
neural plate: portion of ectoderm that develops into nervous system
what is the neural tube?
tube that develops from an inward folding of the neural plate that is the actual precursor to the entire central nervous system
how is the neural tube created?
neurulation
- conformational change change of the neural plate
steps of neurulation
1) the neural plate sinks in and folds to form the neural groove
2) the lateral parts of the groove become walls called the neural fold
3) the fold come together medially and form the neural crest
4) the neural groove closes and forms the neural tube
what are the neurotube defects?
neuropore
- openings/gaps in the neural tube due to failure to seal and close neural tube
anencephaly
- incomplete brain or skulls due to the rostral end of the of the neural tube being folded improperly
spina bifida
- results from failed closing of the caudal part of neural tube
- sac of spinal fluid potruding from mid lower back
what are the parts of the neural tube? what do tthey become?
forebrain / prosencephalon
- diencephalon: thalamus and hypothalamus & third ventricle
- telencephalon: cerebral cortex, cerebral hemispheres basal ganglia & lateral ventricle
midbrain / mesencephalon
- tectum: roof - superior(visual) and inferior (auditory)
colliculius
- tegmentum : floor - red nucleus,
ventral tegmental area,
periaqueductal gray
- cerebral aqueduct
hindbrain / rhombencephalon
- rostral: cerebellum and pons
- caudal: medulla
- fourth venticle
forebrain looks?
optic vesicles?
secondary vesicle sprouting laterally off the diencephalon to form the optic nerves and retinas
mid brain differentiation?
hind brain?
how was neruogenesis prooved?
BrdU
what promotes vs. impairs neurogenesis?
where do neural stem cells exist?
- SVZ : development
- dentate gyrus of hippocampus
when are most cells generated?
before birth 5th week-5th month of pregnancy
pruning?
loss of neurons from birth to ages 2-3 (use it or loose it)
what are the parts of the ventricular system?
- third ventricle
- cerebral aquaduct
- fourth ventricle
- spinal cord
what lines the walls of the ventricles?
ependymal cells
where is the CSF made?
choroid plexus
what is the sequence of CSF flow?
1) lateral ventricles
2) 3rd ventricle
3) cerebral aqueduct
4) 4th venticle
where does the cerebral aqueduct lay?
between the tectum and tegentum of the midbrain
where does the 4th aqueduct lay?
pons and medulla
what may occur if CSF flow is blocked?
hydrocephalus
what is the central/spinal canal?
the small fluid-filled chamber in the center of the spine
what does a rostral cross-section look like in terms of ventricles?
- 3rd ventricle may be absent or very small
- paired chambers = lateral ventricle
- lateral also can be very small at the lateral areas of the cortex due to its horn like shape
where is the caudate located?
lateral to the lateral ventricles
where is the thalamus located?
lateral to the 3rd ventricle
rostral vs. caudal views of the brain? coronal
mid sag section
MRI
visualize structure of the brain by using energy of electromagnetic wave to excite protons in H atoms, differentiate between gray and white matter
fMRI
superimposes change in blood flow over time
PET
looks at the delivery of oxygen labeled with positron emitting isotope (radioactive compound that emits protons that are detected on imaging) of oxygen
- active neurons, using glucose, are more likely to take up the isotope
