Chapter 14 [ EXAM #1 ] Flashcards
what is embryology
brain begins as neural tube from ectoderm
what is neural tube
walls become future brain tissue
becomes 4 enlarged ventricles
what are 2 neural tube defects
anencephaly (without brain)
spina bifida (bones of the spine don’t form properly around part of the baby’s spinal cord)
what 2 things reduce neural tube defects
B12 and folic acid
what is cerebrum
paired hemispheres with cerebral cortex
complex higher functions
what is diencephalon
right and left thalamus link brainstem with cerebrum
gateway to cortex
sensory filter and relay
function of hypothalamus
id
autonomic control of visceral and endocrine functions
where is hypothalamus
diencephalon
where is pineal gland
diencephalon
function of pineal gland
sleep-wake cycle
what are 3 components of brainstem
midbrain
pons
medulla oblongata
function of midbrain
process visual and auditory reflexes
function of pons
bridge sensory and motor to/from brain, spinal cord, cerebellum, cerebral cortex
function of medulla oblongata
relays all info between brain and spinal cord (and cerebellum)
contains autonomic centers (respiration, heart, digestion)
4 ventricles of brain
lateral ventricles (2)
3rd ventricle
4th ventricle
what are protective mechanisms of brain?
cranium bones
cranial meninges
CSF
BBB
function of BBB
isolates brain from systemic blood circulation
how many dura mater layers are in the skull vs the spine
2 in skull
1 in spine
what are the 2 layers of dura mater
outer periosteal
inner meningeal
the dura mater forms…
dural folds that add stability and support
sinuses
arachnoid mater composes of…
trabeculae across subarachnoid space
function of arachnoid granulations
one-way valve determines CSF volume
function of pia mater
astrocytes anchor to brain surface
volume of CSF in brain
~ 150 ml
function of CSF
cushions, supports, surrounds, and reduces brain weight
transports O2, glucose, chemical messengers. and wastes to/from neurons/neuroglia
CSF is formed by…
choroid plexus
choroid plexus is formed by…
special capillaries surrounded by ependymal cells
function of choroid plexus
release regulated CSF (made from plasma) into ventricles (~ 500 ml / day)
what forms blood-CSF barrier
tight junctions between ependymal cells
CSF moves into _______ through _______ in _______
CSF moves into subarachnoid space through apertures in 4th ventricles
location of dural sinuses
within dural folds, venous blood vessels, drain into int. jugular veins
does the superior sagittal sinus contain arachnoid granulations
yes, the superior sagittal sinus contain arachnoid granulations
what is hydrocephalus
interrupted CSF circulation
what might be some causes of hydrocephalus
arachnoid granulations not functioning/present
choroid plexus defects
problem with apertures in 4th ventricle
CSF circulation obstructed
CSF is made from _____ and recycled back into the _____
plasma, plasma
what cells are in the BBB vs the B-CSF
BBB: astrocytes
B-CSF: ependymal
what 3 things form BBB
capillary endothelial cells with tight junctions
thick basement membrane
astrocytes
what can diffuse across BBB
lipid soluble (O2, CO2, alcohol, steroids)
what is transported across BBB
glucose and AAs
function of thick basement membrane in BBB
holds cells to each other
astrocytes to endothelial
function of astrocytes in BBB
control BBB permeability by releasing chemicals
chemicals affect endothelium permeability
why does BBB have exceptions in brain
BBB prevents hormones to enter blood
what are exceptions to BBB
hypothalamus
pituitary gland
pineal gland
choroid plexus
why does BBB present a challenge for drug delivery?
BBB is selectively permeable
allows lipid soluble materials
what composes brain stem
medulla oblongata
pons
mid brain
function of brain stem
produce autonomic behaviors
pathway for tracts
associates with 10/12 brain nerves
ascending tracts relay _____ info
sensory
descending tracts relay _____ info
motor
what are corticospinal tracts
largest motor tracts from cerebral motor cortex to spinal cord
what is the term for crossing over of tracts
decussation
where does decussation occur
medulla oblongata (anterior of pyramids)
what are the pyramids
bundles of motor axons in the medulla oblongata
what is peristalsis
movement of food (digestive)
what does the pons connect
pons connects brain to spinal cord
pons connects cerebellum to brain
what composes the pons
part of ascending and descending tracts
sensory and motor nuclei of cranial nerves
what is corpora quadrigemina
2 pairs of sensory nuclei for visual and audial
superior colliculi and inferior colliculi
function of superior colliculi
visual sensory
function of inferior colliculi
audial sensory
startle reflex: loud sound reaction
function of substantia nigra
neurons release dopamine
dopamine controls subconscious muscular movement
damage may cause Parkinson’s
location of substantia nigra
midbrain
function of cerebellum
finely controls motor movement and stores motor movement memory unconsciously
location of arbor vitae
cerebellum (internal tracts)
function of cerebellar peduncles
tracts link cerebellum to brain
info in and out cerebellum
what is cerebellar ataxia
impaired muscular coordination due to alcohol, stroke, trauma
location of diencephalon
surrounded by cerebral hemispheres
encloses 3rd ventricle
function of diencephalon
sensory relay before cerebral cortex
control of autonomic functions
emotions
links nervous system to endocrine system
diencephalon composes of
epithalamus (roof)
thalamus (walls)
hypothalamus (floor)
what separates the left and right thalamus
3rd ventricle
function of thalamus
relay for all sensory info to primary somatosensory cortex
(“gateway to cerebellar cortex”)
sensory filter (sorts and filters) of what gets to cerebrum
99% of sensory not sent to consciousness
function of hypothalamus
autonomic control center (esp. visceral)
headquarters of ANS
body temperature regulation
controls id
what releases oxytocin
hypothalamus
what is referred to as the feeding and thirst center
hypothalamus
what produces ADH and what is ADH
hypothalamus
ADH are osmoreceptors that detect osmolarity
what does pineal gland produce
melatonin
function of melatonin
helps regulate sleep-wake cycle
what are three dural folds of brain
falx cerebri
falx cerebelli
tentorium cerebelli
