lecture 10/11- CNS Flashcards
meninges are
tissue membranes that lie between bones and the soft tissues of the CNS
meninges lie between bone and CNS tissues to…
stabilize and protect neural tissue
what is in the meninges?
- dura mater
- arachnoid membrane
- pia mater
Functions of the cerebrospinal fluid (CSF)
- physical protection
- keeps brain tissue buoyant, reduces pressure
- absorbs shock - chemical protection
- acts as a vehicle for delivering nutrients to the brain
-removes waste
- allows for a tightly regulated extracellular environment
where is CSF produced?
produced the the choroid plexus of the ventricles
What is the choroid plexus of the ventricles?
- meeting of capillaries and ependymal cells
- plasma is filtered into ventricles
–> ependymal cells selectively transport solutes, water flows by osmosis
CSF reabsorbtion
it is reabsorbed into the blood at arachnoid villi
blood-brain barrier
tight junctions prevent movement of larger solutes between endothelial cells
brain capillaries have — juncitions
tight
limits movement of hydrophilic substances that would otherwise pass easily through paracellular pathway
metabolic needs of neural tissue: oxygen
oxygen passes freely across the BBB
brain receives 15% of blood pumped by heart at rest
metabolic needs of neural tissue: glucose
brain is responsible for about 20% of the body’s total glucose consumption
progressive hypoglycemia leads to confusion –> unconsciousness –> death
gray matter of the brain
clusters of cell bodies= nucleus
dendrites, synapses
white matter of the brain
tracts of myelinated axon fibers
contains very few cell bodies
dorsal and ventral horn of the spine
dorsal= back= sensory= afferent
ventral= front= motor= efferent
ascending and descending tracts
ascending tracts= bundles of axons carrying messages from spinal cord to the brain
descending tracts= bundles of axons carrying messages from the brain to the spinal cord
3 brain regions to know
- forebrain
- brainstem
- cerebellum
cerebellum is for
motor memory, coordination, movement and execution
“little brain”
integrates sensory and efferent information to ensure movement is coordinated
3 sections in the brainstem
MC QUESTION
- medulla
=regulates HR - pons= respiration “highway”
- midbrain= motor learning
where do the 12 cranial nerves emerge from
the brainstem
name 5 cranial nerves
olfactory
optic
vestibulocochlear
glossopharyngeal
vagus
what is the function of basal gangia?
control of limb movement, eye movements, cognitive functions
what diseases would loss of neurons in the basal ganglia region cause?
parkinson’s disease
huntington’s disease
thalamus
relay station; receives sensory and motor info
projects fibers to cerebrum for information processing
hypothalamus
homeostasis and behaviour
pituitary gland
anterior= secretes hormones
posterior= secretes neurohormones made in the hypothalamus (oxytocin and vasopressin)
pineal gland
secretes melatonin
regulates sleep/wake cycles
what is the hypothalamus referred to as?
homeostatic control center
- activates SNS
- maintains body temp
- body osmolarity
- reproductive funtions (oxytocin, FSH, LH)
- food intake
- limbic system (emotions)
- cardiovascular control center
- secretes tropic hormones
limbic system
lies around the brainstem
centers for emotion, memory and learning are found here
3 components of the limbic system
-cingulate gyrus
- hippocampus
- amygdala
broca’s area
expression and vocalization occurs in broca’s area
Wernicke’s area
initial sensory processing (understanding) occurs in Wernicke’s area
damage to broca’s area?
expressive aphasia
- can understand but can’t express themselves/respond
-frustrating for patient
damage to wernicke’s?
receptive aphasia
- loss of understanding but expression maintained (without meaning)
