Week 5 Quiz Flashcards
Includes lecture 6 and 7 (22 cards)
what arteries are a part of the anterior (carotid) system and where are they located?
anterior cerebral artery: vertical arteries that protrude from the top of the carotid system
middle cerebral artery: lateral branches off of the anterior cerebral artery
(diagram on L6S3)
what arteries are a part of the posterior (vertebral-basilar) system and where are they located?
posterior cerebral artery: branches off of the basilar artery, below the middle cerebral artery
basilar artery: unilateral artery that runs along the front of the pons
vertebral artery: branches off of the basilar artery that lie below the posterior cerebral artery
internal carotid artery: long artery that rins on either side of the basilar artery
vertebral artery: smaller branches behind the internal carotid artery
(diagram on L6S3)
which sections of the brain are supplied by which arteries?
anterior cerebral artery: supplies the anterior cerebral territory including the inner side of the frontal and parietal lobe
posterior cerebral artery: supplies the posterior cerebral territory which includes the inner side and outer border of the occipital lobe and bottom of temporal lobe
middle cerebral artery: supplies the middle cerebral territory that encompasses the lateral sides of the cortex, also supplies the insula
(diagram on S6L4 & 5)
where do the lenticulostriate arteries lie and what do they supply?
LSA branch off of the middle cerebral arteries enter the anterior perforated substance of supply blood to the internal capsule
(diagram on L6S7)
what does an angiography allow you to image?
angiographies involve injecting an iodine based dye that labels arteries, capillary beds, and veins and venous sinuses depending on how long the dye has to travel
what arteries can be seen from the back of an angiography?
anterior cerebral artery: main artery that branches off from the midline
anterior communicating artery: dip between the midline and the anterior cerebral artery
(diagram on L6S13)
what arteries can be seen on an axial T2 MRI?
blood vessels appear dark on T2 MRIs because the blood is in motion
anterior cerebral artery: medial arch of the long horizontal branch
middle cerebral artery: lateral branches of long horizontal branch
posterior cerebral artery: arteries that lie along the edges of the midbrain
(diagram on L6S16)
what do PET scans and fMRIs label?
PET: labels blood flow since increased blood flow correlates to increased activity
fMRI: labels hemoglobin
stoke vs aneurysm?
stroke: when blood flow is slowed or stopped
aneurysms: a weakened, ballooning section of the artery
what are the major components of the blood brain barrier?
arachnoid: surrounds the CNS and lays on the outside of the subarachnoid space
choroid epithelium: lines ventricles, areas in the arachnoid villi are closed off
tight junction in arachnoid barrier: tight junctions on outer arachnoid barrier
things can diffuse through pia mater and things in ventricle can diffuse through ependyma into CNS
(diagram on L6S29)
what are the circumventricular organs and where are they located?
(structures that are lacking a BBB)
subfornical organ: on the forehead of the seahorse
pineal gland: lies on the back of the head of the seahorse, near tectum
vascular organ of the lamina terminalis: on the bridge of the nose of the seahorse
median eminence: underneath the chin of the seahorse
area postrema: lies on the medulla in front of the cerebellar tonsil
(diagram on L6S31)
what are the major veins in the venous system as seen from the outside of the brain?
vein of trolard: largest vein that runs vertical across the middle of the brain and stops along the top of the temporal lobe
superficial middle cerebral vein: anterior branch that comes off of the vein of troland
(diagram on L6S34)
what are the major veins in the venous system as seen from the inside of the brain?
superficial middle cerebral vein: lies near corpus callosum towards the front of the frontal cortex
choroidal vein: large vein that lies above the superficial middle cerebral vein
superior anastomotic vein (of Trolard): vertical vein that lies along the area between the parietal and occipital lobe
internal cerebral vein: lies on the posterior side of the choroidal vein
great cerebral vein (of Galen): horizontal vein that branches from back of choroidal vein
basal vein (of Rosenthal): main horns in the middle of the brain
(diagram on L6S33)
what are the major tributaries of the straight sinus and where are they located?
internal cerebral vein: lies above the eye of the seahorse
great cerebral vein (of Galen): end of the internal cerebral vein near the pituitary gland
basal vein (of Reosenthal): branches off of the great cerebral vein and runs underneath the pituitary gland
(diagram on L6S36)
what do receptors encode?
the nature, location, intensity, and duration of stimuli
what are the different types of receptors based on stimulus location and stimulus type?
location:
interoceptors (within body)
proprioceptors (position sense)
exteroceptors (outside body)
type:
chemoreceptors
photoreceptors
thermoreceptors
mechanoreceptors
nociceptors
how do hair cells transmit signals?
- in response to deflection in the direction of the longest microvillar process hair cells produce a depolarizing receptor potential, but no action potentials
- the receptor potential spreads passively to the synaptic area of the hair cell, where it increases release of neurotransmitter onto the peripheral ending of an eighth nerve fiber
- the postsynaptic potential then spreads passively to the trigger zone of the nerve fiber and initiates the firing of action potentials, which are conducted to synaptic terminals in the CNS
what do each type of receptors detect?
meissner corpuscles: touch, involved in two-point discrimination
merkel cells: touch, involved in two-point discrimination
pacinian corpuscle: vibration
ruffini ending: pressure
free nerve endings: pain, temperature, itch, touch
endings around hairs: touch
what are Eimer’s organs?
bulbous papillae that detect touch such as moles nose
what are the mechanisms of reacting to pain?
- injuring a localized area of skin causes a receptor potential in nociceptive endings located there
- if the receptor potential depolarizes the receptor’s trigger zone to threshold, action potentials spread in both directions: proximally toward the spinal cord and distally into nearby branches of the same nociceptor
- impulses reaching the spinal cord cause release of glutamate and neuropeptides onto second-order neurons
- impulses reaching sensory endings cause peripheral release of glutamate and neuropeptides
- thus, two different branches of a single neuron form the afferent and efferent limbs of the axon reflex circuit, the neuropeptides are vasoactive and cause flare and edema
what do the different receptors in muscles and joints do?
muscle spindles: detect muscle length, stretch, stops firing as muscle contracts then fires a burst of action potentials as muscle relaxes
golgi tendon organs: detect muscle tension, fires faster as muscle contracts and increases tension, falls silent as muscle relaxes
gamma motor neurons: regulate the gain of the stretch reflex by adjusting the level of tension in the intrafusal muscle fibers of the muscle spindle, this mechanism sets the baseline level of activity in α motor neurons and helps to regulate muscle length
and tone
how are PNS nerves structured?
bundles of nerve axons wrapped in perineurium form endoneurium or nerve fascicles, many endoneurium are wrapped in epineurium
(diagram on L7S26)
