chapter 3 Flashcards
what are the 2 major divisions of the nervous sytem?
central and peripheral
what is the CNS?
brain and spinal cord
what is the PNS?
somatic and autonomic
where is the PNS located?
outside the brain and spinal cord
what is the somatic nervous system composed of?
voluntary movements using afferent and efferent nerves
what is the autonomic nervous system composed of ?
involuntary bodily responses with afferent and efferent nerves
sympathetic nervous system is also called?
fight or flight response
afferent nerves of autonomic
sensory information on state of organs
afferent nerves of somatic nervous system
brings sensory information into the CNS
efferent nerves of the somatic nervous system
carries out motor functions of the CNS
autonomic nervous system acts on
smooth muscle, glands, and cardiac muscles
where does the sympathetic autonomic system affect in the CNS?
thoracoulmbar
where does the parasympathetic autonomic affect in the CNS?
craniosacral
where are the ganglia of the sympathetic system?
close to the spinal cord in a chain
where are the ganglia of the parasympathetic?
close to the target organs
how long are the postganglionic fibers in the sympathetic?
long
how long are the postganglionic fibres in the parasympathetic?
short
cranial nerves
- 12 pairs in the periphery that originate on ventral surface of the brain instead of the spinal cord
describe the cranial nerves
mostly olfactory and optic sensory nerves, some autonomic, motor and sensory
describe autonomic motor cranial nerves
parasympathetic
what protects the CNS?
- 3 layers of meninges, cerebrospinal fluid, encased in bone
what is the dura mater?
- hard outer layer of meninges that restricts movement within the skull.
what do the sinus do in the dura mater?
- drains deoxy blood and cerebrospinal fluid waste
arachnoi mater
-2nd layer
subarachnoid space
- contains cerebrospinal fluid and large blood vessels
PIA mater
- adheres to the surface of the CNS and encloses it
what are the locations of the cerebrospinal fluid?
-subarachnoid space, central canal, ventricles
central canal
channel that runs the length of spinal cord
hydrocephalus
water pressure buildup or tumor obstructing channel of CSF
what does the cerebrospinal fluid help with?
shock absorption, support and cushioning
ventircles
large internal chambers that produce and circulate cerebrospinal fluid
where is the cerebrospinal fluid made?
choroid plexus of ventricles
choroid plexus
capillary networks that protrude into ventricles via pia mater
what does the CSF clean?
Metabolites and toxins
Blood Brain Barrier
highly packed cells surrounding blood vessels, epithelial, and glial cells that keeps the CNS physiologically separated from the PNS
what does the BBB do?
keeps molecules out of the brain using semi permeable transport mechanisms to maintain electrochemical homeostasis
How is the BBB broken down?
high blood pressure, high concentrations of non-permeable molecules through drug effects, brain injury or disease, infection, microwaves, and radiation
when is the BBB not formed
at birth
what are the cells of the nervous system
neurons, glia, and satellite cells
what are neurons?
specialized cells for electrochemical signals, reception, conduction, and transmission
how are neurons classified?
by the number of structures emanating from cell body
nerve fibre
nerve process (axon or dendrite)
nerve
bundle of axon fibres in PNS
Tract
bundle of axon fibres in CNS
ganglion
cluster of neuronal cell bodies in PNS
nucleus
cluster of neuronal cell bodies in PNS
what are the major types of glia?
astrocytes, microglia, oligodendrocytes
what are astrocytes
largest glia cells with 9 substance and star shaped
what do astrocytes do?
provide metabolic support to neurons, clean up NT’s, signal NT’s hold neurons in place, regulate ions in extracellular space, regulate blood flow, form the BBB
what do astrocytes do to help synapse?
rearrange, control, establish, and maintain
astrocyte synctium
connected by gap junctions, dwelling place of thoughts
what do microglia do?
macrophage, multiply in response to injury/ disease, regulate cell death, active immune defense, synaptic plasticity
what are oligodendrocytes?
myelin-rich extensions that wrap around axons in the CNS
what does the myelin sheath do?
speed conduction, nourish, axons, white matter in brain, necessary for complex nerve interactions, occurs for 20 years postnatally
what are Schwann cells?
myelin cells of the PNS that guides regeneration and only wraps around one axon segment
what is the myelin sheath composed of?
fast and proteins
how is the myelin formed?
synthesized by oligodendrocytes and Schwann cells to induce saltatory conduction and provide nutrients
loss of myelin leads to what?
multiple sclerosis
anterior
nose or front
posterior
tail or back
dorsal
top of head
ventral
bottom of head
medial
midline
lateral
away from midline
function of spinal cord
links brain to body and body to brain
what are the nerve roots of the spinal cord?
dorsal and ventral
dorsal root
sensory afferent nerves that are unipolar
ventral root
motor efferent nerves that are multipolar
what are the 4 regions of the spinal cord?
cervical, thoracic, lumbar, sacral
internal structure of spinal cord
white matter in periphery, grey matter in middle
white matter
myelinated axons
grey matter
unmyelinated cell bodies
what are the 4 main columns of the spinal cord?
dorsal horn, ventral horn, lateral horn, intermediate column
dorsal horn
somatosensory nuclei
ventral horn
motor neurons, dendrites, and cell bodies, innervate skeletal muscles or internal organs
intermediate column
automatic nerves innervate visceral and pelvic organs
myelencephalon
medulla and origin of reticular formation
medulla
ascending and descending tracts at core
reticular formation
composes core of hindbrain and midbrain and is a nuclei of arousal system
metencephalon
ascending and descending tracts, cerebellum, pons
cerebellum
sensorimotor coordination, maintains fine motor skills, role in cognition, language, attention
pons
swelling on ventral surface of brain stem that contains reticular formation and transfers information between the brainstem and the cerebellum
Mesencephalon
midbrain that contains the tectum and tegmentum
tectum
superior colliculi (visuomotor), inferior colliculi
tegnmentum contains
reticular formation, red nucleus, substantia nigra, periaqueductal gray
red nucleus
sensorimotor, motor coordination, hemoglobin and ferratin
substantia nigra
sensorimotor, reward, addiction, and movement, melanin
periaqueductal gray
analgesia, defensive behaviour, gate control theory of pain
how does the gate control theory of pain work
releases endorphins and dense endorphin receptors
the diencephalon is composed of what?
thalamus, hypothalamus
what is the thalamus composed of?
sensory relay nuclei in two lobes
what is the lateral geniculate nuclei for?
sensory relay in thalamus for vision
what is the medial geniculate nucleus for?
sensory relay in the thalamus for audition
what is the ventral posterior nucleus for?
sensory relay for touch
what is the hypothalamus composed of?
pituitary gland, mammillary bodies, optic chiasm
what does the pituitary gland do?
releases hormones
what doe hormones do?
modulate behaviours of stress, reproduction, feeding etc
what is the telencephalon composed of ?
cerebral hemispheres with cortex convolutions, limbic system, and the basal ganglia
what separates the cerebral hemispheres
longitudinal fissure called the corpus callosum
what are gyri?
hills on the cortex
what are sulci?
valleys on the cortex
what is the precentral gyri?
primary motor cortex
what is the postcentral gyri?
primary somatosensory cortex
what is the superior temporal gyri for?
auditory
what is the neocortex?
6 layers of cortex with columnar organization
what neuron make up the neocortex?
pyramidal neurons and stellate neurons
what are pyramidal neurons?
large, multipolar neurons
what are stellate neurons?
interneurons that are small and star shaped
what is the limbic system for?
regulation of motivated behaviours: 3 F’s
what is primitive cortex composed of?
hippocampus and cingulate cortex
what is the amygdala for?
emotional memory, fear and anger
what is the basal ganglia for?
voluntary motor control, procedural learning
what is the best ganglia composed of?
amygdala, nucleus accumbens, striatum, globus pallidus
what is the nucleus accumbens for?
reinforcement learning, drug and reward learning
what is the striatum composed of?
caudate nucleus and putamen
what is the dura
first layer of the meninges though matter, restrict movement within in skull
what is the arachnoid matter?
second layer of meninges web like has subarachnoid space right below it
contains cerebrospinal fluid and large blood vessels
what is the pia matter?
third layer of meninges
delicate
adheres to surface of CNS
maintain oxygen level in brain
BBB allows ____ soluble materials to pass
lipid
water can or cannot cross the BBB?
cannot
children have reflexes that adults do not because their axons are not ____ yet
myelinated
sympathetic nerves are located in the ___ region of the spinal cord
thoracolumbar
parasympathetic nerves are located in the ___ region of the spinal cord
craniosacral
location of parasympathetic and sympathetic ganglias
parasympathetic - close to target organs
sympathetic- close to spinal cord
lengths of postganglionic fibres of parasympathetic and sympathetic pathways
parasympathetic - short
sympathetic - long
which one has more branches postganglionic fibres - parasympathetic or sympathetic?
sympathetic
damage to medulla produces ___ chances of survival
low
ipsilateral means
same side
contralateral means
opposite side
hydrocephalus
overflow of CSF in Brain
what do the ventricles in the brain do
produce CSF
ways to break the BBB
high BP birth defect high concentration of non permeable molecules injury infection radiation
2 main types of cells in the nervous sytem
neurons and glial cells
multipolar neurons
a neutron with more than 2 processes extending from its soma
unipolar neuron
neuron with one process extending from its soma
bipolar neurons
neuron with 2 processes extending from its soma
what do microglia do?
acts as macrophages, multiple in response to injury/ disease
active immune defense
fast acting
why do microglia ac as an immune defense when there are antibodies in the brain
because antibodies can’t pass the BBB
coronal plane
from ear to ear
sagittal plane
from nose to back of head
axial (transverse plane)
upper and lower halves
what structures are present in the diencephalon
thalamus hypothalamus sensory relay nuclei mammillary bodies optic chiasm
when looked at from above, what shape does the spinal cord look like
butterfly
where is white matter found in the spinal cord
in periphery of butterfly shape
where is grey matter found in the spinal cord
in the middle of the butterfly shape
in lower regions of the spinal cord, what happens to the ratio of grey matter to white matter
it increases
what are the 4 columns of the spinal cord (not the 4 bone regions)
dorsal horn
ventral horn
lateral horn
intermediate horn
what are the 5 major divisions of the brain
telencephalon diencephalon mesencephalon metencephalon myelencephalon
what is an analogy for gyri and sulci/ fissures
gyri are hills
sulci/fissures are valleys
what separates the frontal and parietal lobe
central fissure
what separates the temporal lobe from the other lobes
lateral fissure
what separates the two hemispheres of the brain
longitudinal fissure
where is the precentral gyri and what does it do
present in frontal lobe acts as primary motor cortex
where is the postcentral gyri located and what does it do
in parietal lobe
acts as primary somatosensory cortex
where is the superior temporal cortex located and what does it do
in temporal lobe, it acts as an auditory cortex
functions of hippocampus
spatial learning and memory
functions of cingulate cortex
receives input from thalamus and neocortex
what structures are present in the primitive cortex of the limbic system
hippocampus
cingulate cortex
what are the subcortical structures present in the limbic system
amygdala
fornix
septum
mammillary bodies
what is the amygdala involved with?
emotional memory
fear and anger
what is the kluver-bucy syndrome and what causes it
- caused my malfunction of amygdala characterized by inappropriate sexual beahviour
what does the fornix do
acts as tract for white matter
what is basal ganglia
network of structures important for voluntary movement and procedural learning
what are the cortical structures involved in the basal ganglia
amygdala
nucleus accumbens
striatum (caudate nucleus+ putamen)
globus pallidus
the basal ganglia is part of the ___ system
limbic
what structures are present in the primitive cortex of the limbic system
hippocampus
cingulate cortex
what kind of cells form the BBB?
astrocytes
the stellate calls in the fourth layer of the neocortex specialize in
receiving sensory signals from the thalamus
