Diencephalon, Basal Ganglia, Brain Ventricles Flashcards
thalamus
“inner chamber” or “bedroom”
2 hemispheres above the brainstem
RELAY STATION (sensory input)
gateway to cerebral cortex
functions of thalamus
relays sensory info (besides smell)
perception of pain, temp, touch
sense of pleasantness/noxiousness
maintains cortical arousal, attention, sleep-wake cycle
Thalamic Nuclei
7 groups
- medial
- lateral dorsal
- lateral ventral
- anterior
- intralaminar
- reticular
- midline
Medial Geniculate body
relays auditory info from subcortical midbrain to auditory cortex temporal lobe
HEARING
Lateral Geniculate body
info from optic nerve to primary visual cortex in occipital lobe
VISUAL
Ventral Posterior Medial
input (pain/temp/touch) form the trigeminothalamic tract from face nerves (V,VII,IX,X)
Ventral Lateral & Anterior (VL) (VA)
Both receive input from basal ganglia & cerebellum, send info to motor cortex
VL – motor planning
VA – speech production
Blood supply to thalamus
the posterior communicating artery (PCA) is very important to the blood supply for thalamus
Pituitary Problems
CUSHING DISEASE
- endocrine (hormone) disorder via tumor on pituitary gland
- high levels of cortisol
- moon facies, emotional disturbances, hypertension, buffalo hump, obesity, amenorrhea, muscle weakness
Pituitary Problems
ACROMEGALY
- extreme largeness
- caused by tumor
- pituitary produce too much growth hormone
symptoms: large stature, large nose/jaw/hands, hypertension, peripheral neurpathy
Epithalamus
superior/posterior thalamus
- connects limbic system to forebrain and other parts!!!!!!!
- sleep-wake cycle, olfactory reflexes, reward & aversion
parts of epithalamus
Pineal gland: produces melatonin, sleep-wake cycle, circadian rhythms
Habenula: olfactory reflexes/stress
Salivate: food, gag, noxious
Stria Medullaris: white matter tract connects Habenula to limbic system
Subthalamus
below thalamus
- connects basal ganglia to motor cortex
- modulation of movement outside B.G
Damage of subthalamus
hemiballismus: one sided involuntary flinging of limbs
tremors, obsessive compulsive, impulsivity
Deep Brain Stimulation
success to relieve tremors and involuntary movements for sub thalamus damage by placing a simulator
3 large nuclei of Basal Ganglia
- caudate nucleus
- globus pallidus
- putamen
caudate nucleus
“having a tail” c-shape
head, body, tail
tail has bulge (amygdala) to limbic sys
Regulate emotions (fear, aggression, emotional meaning to memories, reward processing & decision making)
3 large nuclei functionally together
striatum
3 large nuclei anatomically together
lenticular nucleus
direct pathway of basal ganglia
facilities movement
indirect pathway of basal ganglia
inhibits movement
Connections cortical motor areas
- using dopamine (substantia nigra) regulates posture, balance, swinging arm movements, walking
- activating, sustaining, inhibiting motor movements
dyskinesias
involuntary, erratic movements (fluid dance like)
atheosis
slow & withering (limbs, trunk, neck, face, tongue)
chorea
involuntary unpredictable rapid contractions in face/arms/legs
akinesias
lose ability to move muscles on own
( frozen )
rigidity
muscles stiff and tighten involuntarily
dystonia
involuntary muscle contractions, repetitive movement or abnormal postures
bradykinesia
slowness of movement, difficulty initiating movement
Basal ganglia symptoms
Dyskinesias, tremors, athetosis, chorea, akinesia, rigidity, dystonia, bradykinesia
Parkinson Disease
progressive neurological disease
“shaking palsy”
- degeneration of substania nigra in midbrain, loss of dopamine to BG
symptoms: muscle rigidity, dyskineasis, resting/pill-rolling tremors, shuffling gait, weak voice, dysarthria, flat affect, dysphagia
Parkinson Surgery
Deep Brain Stimulation
surgical insertion of brain pacemaker that stimulates basal ganglia, reducing symptoms
Parkinson Surgery
Pallidotomy
cells in globes pallid us are selectively destroyed using heated probe reducing symptoms
Huntington Disease
progressive, hereditary neurological disease due to degeneration of basal ganglia
(~35 years)
Autosomal dominant pattern of inheritance
symptoms: chorea, athetosis, emotional/personality changes, dysarthria, dysphagia, dementia
ventricles
fluid-filled spaces in brain
4 total
Left & Right ventricle paired
Third ventricle
Fourth ventricle
choroid plexus
each ventricle has this structure that produces cerebral spinal fluid
2 Lateral Ventricles right & left
located in each hemisphere
paired
c-shaped
Third ventricle
from diencephelon
single structure
slit like between 2 thalami, part of hypothalamus
may be absent in 30% of humans
Fourth ventricle
most inferiorly located
lies within brainstem
Movement of ventricles
CSF is going down thru spinal cord:
- lateral ventricles drain to 3rd ventricle via Forman of Monroe
- 3rd ventricle drains to 4th
- 4th ventricle drains to central spinal canal
- drains to subarachnoid cisterns between arachnoid & Pia mater
function of CSF
- provides mechanical protection/cushioning
- facilitates homeostasis
- facilitates communication between CNS and PNS and immune system
Cerebral Spinal Fluid is
- clear/colorless liquid
- choroid plexus locate in each ventricle
- found in ventricular system, cerebral, spinal, arachnoid spaces in CNS
production of CSF
- water
- protein 9
- neurotransmitters (helpful diagnostic purposes)
- glucose
CSF alterations
production changes with
- aging
- hypertension
- atherosclerosis
- sleep deprivation
CSF impact on dementia/alzheimers
- aging process lead to hypo secretions of CSF, increased connective tissue & changes in vascular system causes CSF to back up
- interferes with brain waste clearance
Subarachnoid hemmorage complication (CSF)
- obstruction
- hemmorage caused inflammation response in brain that causes hypersecretion
Holes in meninges (CSF)
- decrease CSF pressure
- postural headaches
- related to buoyance of brain & difficulty keeping brain supported if not enough CSF
Hydrocephalus
Excess CSF builds up in ventricles, enlarging one or more
Diagnose hydrocephalus
CT scan, MRI, Lumbar puncture (spinal tap)
ventricles can misshapen
