2. Intro to Neuroanatomy Flashcards
building block of nervous system
neuron; they are arranged to form different structures
groups of neurons are called
nuclei
cells are which type of matter
gray matter (appearance in dissection; cells appear gray)
axons are which type of matter
white matter (fibers, appear white in dissections)
groups of axons interconnecting different parts of the brain
tracts
a branch of a single axon
collateral
tracts crossing from one side of the brain to the other
decussate
if neurons in one structure have axons that go to a second structure, the first structure is said to __ to the second
project
an axon that divides into 2 branches __
bifurcates
SAME DAVE
sensory = afferent = info enters dorsal
motor = efferent = signals leave ventral
7 major divisions of the CNS (brain and spinal cord)
- spinal cord
- medulla (brain stem)
- pons (brain stem)
- cerebellum (brain stem - some sources don’t)
- midbrain (brain stem)
- diencephalon
- cerebral hemisphere
cerebral hemispheres contain
cerebral cortex and subcortical structures
4 lobes of cerebral cortex
frontal, parietal, occipital, temporal
sulci
infoldings on brain
gyri
surface folds on brain
different functions like vision, audio, motor are found or localized in different ___ regions
cortical
visual cortex is in which lobe
occipital lobe
somatosensory cortex is in which lobe
parietal lobe
auditory cortex is in which lobe
temporal lobe
motor cortex is in which lobe
frontal lobe
cytoarchitectonics
- examine sections through thickness of cortex under a microscope: fine structure varies across the structure
- areas with different structure were given different numbers by Brodmann
- some of the numbered areas correspond to functional areas (area 17 = visual cortex, area 4 = motor cortex)
cortex is arranged in __
layers (usually 6)
3 major cell classes in cortex
projection neurons, pyramidal cells, interneurons (usually GABAergic)
which cortex is area 4
primary motor cortex
what does area 4 do
programming and control of voluntary movement; important in control of the hands and fingers
area 4 is characterized by __ cells in deeper cortex called __ cells
large, Betz (a subset of pyramidal cells)
cortical efferent tracts: signals from cerebral cortex are sent to many ___ structures including multiple __ nuclei and __ __, and to the __ __
subcortical, brainstem, basal ganglia, spinal cord (corticospinal tract)
how do the two brain hemispheres communicate with each other
corpus callosum: axons interconnecting the two hemispheres
hippocampus stores…
memory
basal ganglia does
movement and cognition
3 components of basal ganglia
- caudate nucleus
- putamen (striatum)
- globus pallidus
basal ganglia associated structures
- thalamus (motor region)
- substantia nigra (SN; midbrain)
- subthalamic nucleus (diencephalon)
diencephalon thalamus
composed of subdivisions called nuclei, e.g. LGN (lateral geniculate nucleus) and visual system
diencephalon hypothalamus
regulation of eating, drinking, temperature
midbrain
multiple nuclei
cerebellum does what control
motor control
structure of cerebellum
cerebellar cortex, white matter, cerebellar deep nuclei
4 divisions of spinal cord
- cervical
- thoracic
- lumbar
- sacral
brainstem efferent tracts: several brainstem nuclei give rise to axons that descend to the __ __ to influence __
spinal cord, movement
where does rubrospinal tract run to and from
from red nucleus of midbrain to spinal cord
where does tectospinal tract run to and from
from midbrain (tectum = superior colliculus) to spinal cord
where does vestibulospinal tract run to and from
from vestibular nuclei of medulla to spinal cord
where does reticulospinal tract run to and from
from reticular formation to spinal cord
cranial nerves contain __ information from the head, __ signals to muscles, and enter/leave __ at different levels
sensory, motor, brainstem
olfactory nerve
sensory - smell
*optic nerve
sensory - vision
oculomotor nerve
motor - eye movements
trochlear nerve
motor - eye movements
trigeminal nerve
sensory - taste
motor - face
abducens nerve
motor - eye movements
facial nerve
motor - facial expression
sensory - taste
*vestibulocochlear nerve
sensory - balance and hearing
glossopharyngeal nerve
motor - tongue and pharynx
sensory - taste
vagus nerve
motor and sensory - pharynx, larynx, heart
spinal accessory nerve
motor - head and shoulder
hypoglossal nerve
motor - tongue
motor and sensory functions of spinal cord
motor - control of muscles, reflexes
sensory - input from the body
all encased in bone for protection
what neurons are in gray matter
sensory neurons, motoneurons, interneurons
ascending tract
sensory information
descending tract
motor information
axons that innervate the body are the
primary afferent fibers aka first order fibers
shingles are a disease of __ that cause painful rash and blisters. caused by __ virus, same virus for chickenpox, it is a herpes virus. virus lies dormant in __ but may reactivate as shingles. travels down __ nerve fibers and affects the __.
drg (dorsal root ganglion), varicella, drg, sensory, skin
what activates shingles virus
conditions that weaken body’s immune system such as aging, cancer, or certain drugs increase the chance of activation
motor innervation of muscle
- alpha motoneuron (lower motoneuron; spinal motoneuron)
- cell bodies in ventral horn, axons leave in ventral roots
neurogenesis: most neurons are born as the brain is developing before birth. myelination is not complete at birth, it continues postnatally (motor milestones). there are two regions in which new neurons are born in adults:
- hippocampus (important for memory)
- subventricular zone (source of new neurons for olfactory system)
motor milestones
- 4-6 months: roll over
- 4-7 months: sit up
- 6-10 months: crawl
- 9-10 months: pull to stand
- 13-14 months: walk
comparative neuroanatomy: different species differ in total number of neurons, in brain sizes, and relative sizes of different regions, especially __ __ and __. major subdivisions are all present. sizes of __ do not change, but numbers and arrangements do.
cerebral cortex, cerebellum, neurons
