CNS Flashcards
Afferent is synonymous with input and goes from the
PNS to CNS
Efferent is synonymous with output and goes from the
CNS to PNS
most of the brain is made of neurons
false, Glial(glue) cells make up most of the brain
4 major types of glial cells
Astrocyte function
Blood-brain barrier, structural, regulation of synaptic transmission, metabolic support, regulation of blood flow
Oligodendrocytes vs Schwann
Both types of cells produce myelin and wrap neurons for insulation purposes
Oligodendrocytes are located in the CNS and a single oligodendrocyte can myelinate up to 50 different neurons!!
Schwann cells are located in the PNS and myelinate only a single neuron
Microglia
Resident immune cells
Phagocytoses dead cells and infectious agents
Ependymal cells
Form the epithelium called ependyma
Secrete cerebral spinal fluid (CSF)
Contain cilia for movement of CSF
Have stem cell qualities
CSF
pretty much plasma
we have 150 ml in our system
this volume is recylced 3x a day
produce 500 ml a day
subaracnoid space
Neuroglycopenia
can not get enough glucose
concussions
repeated concussions damage frontal lobe, make bad decisions, CTE after repeated concussions
microcephaly
in the womb, couldn’t receive enough glucose. brain is underdeveloped
Making memories
long term potentiation
When something is more committed to memory, the neurons have stronger connections. 3 vs 5 receptors in the post synaptic
LTP vs LTD
Long term
cannabinoids inhibits LTP increasing LTD while opoids
inhibits LTD and increasing LTP
The effects of LTD and LTP are stronger on thoses under 24, because younger people are more plastic and can learn easier
Functions of the Thalamas
Relay station for all sensory information (except smell).
Screens out unimportant information.
Relay station for motor pathways from cerebral cortex.
Interpretation center for sensory information. Modality (pain, heat, cold, touch pressure) of sensation is perceived here, but not location or intensity.
function of Basal nuclei
Inhibition of muscle tone
Coordination of slow, sustained movements (especially posture).
Selecting purposeful patterns of movement and suppressing useless patterns of movement.
substantia nigra
(latin black stuff) has neurotransmitters/dopaminergic neurons that help with volunteer motor movement
purposeful movements, stop the tremors in Parkinson’s disease
Functions of the hypothalamas
Regulates body temperature
Regulates osmolarity of body fluids (intake and excretion of water).
Regulates food intake. (Appetite and Satiety Centers)
Emotions of rage and aggression.
Regulates Anterior Pituitary function (endocrine system)
Regulates uterine contractility and milk ejection (via oxytocin)
Sleep/wake cycles
BeatsHam
Semaglutide
A GLP1 agonist, stops the feeling of hunger in the hypothalamus
GLP1
a peptide hormone, produced in gut via L cells and some neurons
Secreted biphasically 10 min after eating then a more pronounced secretion about 30-60 min after eating
Physiological functions:
Multiorgan target
Many benefits
gabba
gas pedel for eating, an inhibitory neurotransmitter, it stops the neurons from saying we are hungry
Medulla centers
Cardiac Center (medulla): controls heart rate and strength of contraction
Vasomotor Center (medulla): controls blood pressure
Respiratory Centers (medulla and pons): controls rate and depth of respiration
Digestive Center (medulla): controls vomiting, swallowing, coughing, sneezing
function of a yawn
cools the brain down through the release of CSF, signal to the group that we are safe
reflexes
of synapses in the pathway: Monosynaptic / Polysynaptic
Level of neural processing : Spinal / Cranial
Efferent division controlling effector : Somatic / Autonomic
Developmental pattern : Innate / Conditioned
Innate vs Conditioned
Innate
Inborn
Species specific
Has a definite receptive field
Can occur without cranial intervention
Most persist throughout life
Conditioned
Acquired
Individual
Different receptive field
Need cranial intervention
Temporary
Examples of Reflexes
monosynaptic reflex : Knee jerk
99.9% of reflexes are polysynaptic
headless frog reacts to acid paper
pain is not a cranial reflex
5 Components of Reflex Arc
Sensory receptor
Afferent pathway
Integrating center
Efferent pathway
Effector
The Withdrawl (Lego) Reflex
Step on lego ow
polysynaptic
Voluntary movement
idea - program - execution - movement of skeletal muscle - Feedback to everything
sleep
Clinically, sleep is defined as a state of decreased (not complete loss) motor activity and perception
Reticular activating system: regulation of sleep and awake-fulness
Makes the cortex more receptive to incoming signals
Uses many neurotransmitters including: ACh, norepinephrine, dopamine, histamine
Catecholamine-like drugs such as cocaine and amphetamines target this region of the brain.
Conversely, antihistamines block signaling in the hypothalamus through competitive binding to histamine receptors.
antihistamines have what effects
drowsiness in adults
excitability in children
