Lecture 1 Flashcards
CNS
brain and spinal cord
arises from neural tube
Neural tube
made of ecodermal cells
has fluid filled cavities (ventricles) which contain CSF
PNS
spinal nerves
cranial nerves
sympathetic & parasympathetic nerves
all associated ganglia
enteric nervous system
3 vesicle stage
Prosencephalon/forebrain
Mesencephalon/midbrain
Rhombencephalon/hindbrain
5 vesicle stage
Telecephalon
Diencephalon
Mesencephalon
Metencephalon
Myelencephalon
Telecephalon becomes…
cerebral hemispheres
cerebral cortex
subcortical white matter
basal ganglia
Diencephalon becomes…
thalamus
hypothalamus
epithalamus
Mesencephalon becomes…
cerebral peduncles
midbrain tectum
midbrain tegmentum
Metencephalon becomes…
pons
cerebellum
Myelencephalon becomes…
medulla
Flexures of embryo
Cephalic & Cervical
we lose the cervical, cephalic becomes the axis of the brain
Midbrain axises
superior = rostral
inferior = caudal
anterior = ventral
posterior = dorsal
Remainder of brain axises
superior = dorsal
inferior = ventral
anterior = rostral
posterior = caudal
Brainstem
midbrain
pons
medulla
choroid plexus
produce CSF
present on 3rd/4th ventricle roof & roof/floor of lateral ventricles
CSF roles
provide support for brain/nervous system
regulate chemical environment of brain/ns
acts as a channel for chemical communicators
Pia mater
innermost, very delicate and adheres to surface of brain and spinal cord
Arachnoid mater
joins but is night tightly bound to dura, leaving the subdural space
Dura mater
thickest and outermost of the membranes. serves protective function
Falx cerebri
dura mater that separates the two cerebral hemispheres
Tentorium cerebelli
separates the cerebellum from central hemispheres
Cell body
contains nucleus
dendrites
receive most inputs to cell
axons
carry most outputs
synapses
communication between neurons
myelin sheath
insulated axons
oligodendrocytes
form myelin in CNS
Schwann cells
form myelin in PNS
nodes of ranvier
unmyleninated axon
voltage-gated ion channels
conduction from node to node occurs by saltatory conduction
glial cells
axons are insulated by specialized glial cells that form a lipid myelin sheath that speeds the rate of action potential conduction
unipolar neuron
axon and dendrite from single process from cell body
bipolar neuron
single dendrite and axon from cell body
pseudounipolar neuron
has two processes; one goes to CNS, the other to the PNS
multipolar neuron
most in brain and spinal cord
multiple branches of axons and dendrites
Projection neurons
multipolar neurons w/long axons.
communicate to the PNS
axon terminals are at distant sites
Interneurons
multipolar neurons w/short axons
remain in same region as the cell body location
processes info within the brain region
Functions of chemical transmitters
neuromodulation
mediate rapid communication between neurons
Neuromodulation
cellular signaling
can regulate synaptic transmission, neuronal growth, etc
can inhibit or facilitate signaling of neuron
glutamate
most common excitatory chemical transmitter in CNS
AcTH
most common excitatory chemical transmitter in PNS
White matter brain
myleinated axons
Gray matter brain
cell bodies
Commisure
white matter structure that connects right and left sides of CNS
corpus collusm, anterior/posterior commissure, hippocampal commissure
Ganglia
cluster of cell bodies in PNS
Afferent
takes information towards the brain
sensory
Efferent
takes information away from the brain
motor
SNS arises from
throacic and lumbar spinal levels, T1-L3
Parasympathetic nervous system arises from
cranial nerves and sacral levels (S2-S4)
Autonomic nervous system is controlled by
higher centers in hypothalamus, limbic system, and afferent info from PNS
M1 and S1
are mapped with a motor or sensory homuculus
motor focuses more on limbs, sensory has teeth, tongue, GI, etc.
V1
retinal areas mapped in retinotopic fashion
A1
mapped in tonotopic representation, sensing different frequencies
Cerebral cortex layers
comprised of neocortex (6), paleocortex (6+), archiocortex (3)
allows for higher brain function
Neocortex
6 cell layers
1 = dendrites, some axons
2/3 = neurons that go to other areas of cortex
4 = inputs from thalamus
5 = goes to subcortical structures, brainstem, spinal cord, basal ganglia
6 = goes to thalamus