chapter 7 nervous system Flashcards
what are the basic subdivisions of the nervous system?
central nervous system (CNS)
peripheral nervous system (PNS)
what are the organs in the central nervous system?
brain
spinal cord
what are the functions of the central nervous system?
1) interpret incoming sensory info
2) issues ongoing instructions
what does the peripheral nervous system consist of?
1) spinal nerves
2) cranial nerves
3) ganglia
what are the functions of the peripheral nervous system?
to serve as communication lines between:
1) sensory organs
2) the brain and spinal cord
3) muscles or glands
Afferent =
input
Efferent =
output
somatic =
voluntary
autonomic =
involuntary
somatic sensory nerve fibers carry info from where to where?
from:
sensory receptors
to the CNS
visceral sensory nerve fibers carry info from where to where?
from visceral organs to CNS
motor nerve fibers carry impulses from where to where?
from CNS to effector organs
what are the 2 efferent subdivisions?
1) somatic nervous system
2) autonomic nervous system
what does the somatic nervous system control?
voluntarily controls skeletal muscles
what does the autonomic nervous system control?
involuntarily controls:
1) smooth muscle
2) cardiac muscle
3) glands
what subdivisions is the autonomic nervous system divided into?
1) sympathetic nervous system
2) parasympathetic nervous system
what divisions of the nervous system is acetylcholine found in?
all divisions of NS
what divisions of the nervous system is norepinephrine found in?
sympathetic division of the autonomic nervous system
what division of the nervous system is epinephrine found in?
the sympathetic division of the autonomic nervous system
which division of the nervous system is responsible for the fight or flight response?
the sympathetic nervous system(autonomic)
which division of nervous system is responsible for rest and digest?
the parasympatheic nervous system (autonomic)
what is the function of fight or flight?
increase alertness and metabolic activities
what is the function of rest and digest?
conserve energy and replenish nutrient stores
why remember the parasympathetic division as the D division?
facilitates:
1) digestion
2) defecation
3) diuresis
why remember the sympathetic division as the E division?
associated with:
1) exercise
2) excitement
3) emergency
4) embarrassment
what happens when the heart is stimulated by either the parasympathetic or sympathetic nervous systems?
stimulated by parasympathetic NS: HR slows and becomes more steady
stimulated by the sympathetic NS: increased rate and force of heartbeat
what are the functions of neuroglia?
1) support
2) insulate
3) protect
neurons
what 2 cell types is nervous tissue made of?
1) neurons
2) neuroglia
3 facts about neuroglia?
1) resemble neurons
2) cant conduct nerve impulses
3) never lose ability to divide
where are astrocytes located and what shape are they?
located in CNS they are star shapped
what are the functions of astrocytes?
1) brace and anchor neurons to blood capillaries
2) determine exchanges between blood capillaries and neurons
3) protect neurons from harmful substances in the blood
4) control chemical environment of brain
wheres microglia found and what shape are they?
CNS shaped like spiders
what are the functions of microglia?
1) monitor health of nearby neurons
2) dispose of debris
what are ependymal cells and where are they located?
ciliated glial cells in the CNS that line the cavities of the brain and spinal cordand help circulate CSF
what are oligodendrocytes and where are they located?
glial cells in the CNS
what are the functions of oligodendrocytes
wrap around nerve cells in the CNS and produce myelin sheaths
what are the names of the glial cells in the peripheral nervous system?
1) schwann cells
2) satellite cells
schwann cell function:
form myelin sheath around nerve fibers in the PNS
satellite cell function:
protect and cusion neuron cell bodies
what are the major regions of all neurons?
1) cell body
2) processes
what does the cell body of a neuron contain?
1) nucleus with large nucleolus
2) nissl bodies
3) neurofibrils
what are neurofibrils?
intermediate filaments that maintain cell shape
what are nissl bodies?
rough endoplasmic reticulum
endoneurium =
connective tissue wrapped around a single axon
perineurium =
connective tissue wrapped around a fascicle of axons
epineurium =
connective tissue that wraps around entire nerve structure
what are the 3 functional classes of neurons?
1) sensory
2) motor
3) interneurons
what is nervous tissue matter made of?
neurons and glial cells
what different types of nervous matter is there?
1) grey matter
2) white matter
how many axons does a neuron have?
1 or none
what do axons transmit?
where do axons transmit them?
nerve impulses
away from the cells body to other cells
what is a synapse?
the junction between 2 nerve cells
what is grey matter made of?
1) neuron cell bodies
2) dendrites
3) unmyelinated axons
what is white matter made of?
myelinated axons
what is the function of interneurons?
they facilitate communication between sensory and motor neurons in the CNS
what are nerves?
bundles of axons in the peripheral nervous system
what are tracts?
bundles of axons in the central nervous system
what are nuclei in the nervous system?
clusters of cell bodies in the CNS
what are ganglia?
clusters of cell bodies in the PNS
what is the function of sensory neurons?
transmit impulses from sensory receptors to the CNS
what is the function of motor neurons?
transmit nerve impulses from the CNS to effectors (muscles or glands)
motor nerves are located on which side of the spinal cord?
anterior
sensory nerves are located on which side of the spinal cord?
posterior
3 STRUCTURAL classifications of neurons?
1) uni polar
2) bipolar
3) multipolar
unipolar neurons =
neurons with single process like a T located on sensory side only
bipolar neurons =
neuron with 2 processes (1 axon 1 dendrite) located only in the eyes and ears
multipolar neurons =
motor neurons and interneurons with many dendrite processes and a single axon. most common neuron
2 functions of spinal nerves:
1) a pathway for sensory and motor impulses
2) respinsible for reflexes-our quickest reaction to stimuli
what are the dimentions of the spinal cord?
3/4 in. diameter x 16-18’’ long
the spinal cord extends from where to where?
the foramen magnum to the L1 vertebra
what are the names of the 5 spinal cord nerve sections and how many nerves are in each of them?
cervical / 8 pairs (C1-C8)
thoracic / 12 pairs (T1-T12)
lumbar / 5 pairs (L1-L5)
sacral / 5 pairs (S1-S5)
coccygeal/ 1 pair (CO1)
how many total spinal nerves are there?
31 pairs
cauda equina =
where spinal nerves branch off from spinal cord at L1
what is the tapering end of the spinal cord called?
conus medullaris
what is the filum terminale?
an extention of pia matter from the end of the spinal cord that is attached to the coccygeal segments
what is the cervical enlargement?
an enlargement part of the cervical section of the spinal cord that innervates the upper limbs
what is the lumbosacral enlargement?
the inferior enlargment of the spinal cord that innervates the lower limbs
how can you tell which side is which on a spinal cord
the posterior horn of the grey matter touches the circumference of the spinal cord
what is the epidural space?
the space between the periosteum of the vertebrae and the dura mater
what is narrow subdural space?
potential space separating duramater from deeper arachnoid mater
what is subarachnoid space?
space around spinal cord filled with cerebrospinal fluid between arachnoid mater and pia mater
what is pia mater?
the delicate innermost membrane enveloping the brain and spinal cord
what are the 3 meninges that protect the CNS and what are there respective locations?
1) dura mater- outtermost membrane
2) arachnoid mater- middle layer
3) pia mater- inner most layer of the meninges anchored directly to the brain and spinal cord
what travels through the central canal of the spinal cord?
blood vessels
CSF
when is the nervous system formed?
during the 1st month of embryonic development
what does oxygen deprivation do to brain cells
destroys them
what is one of the last areas of the brain to develope prenatally and how does that affect premature babies?
the hypothalamus, premature babies have trouble regulating body temp due to undeveloped hypothalamus
when does brain growth end?
young adulthood
when neurons die, when are they replaced?
theyre not, when theyre gone they are gone
brain mass declines with age
which kind of desease is the major cause of declining mental function?
cardiovascular disease
the brain is composed of what 4 major regions?
1) cerebrum
2) diencephalon
3) brainstem
4) cerebellum
what are the ridges on the cerebral cortex?
gyrus(gyri is plural)
what are the depressions between gyrus on the cerebral cortex?
sulcus(sulci=plural)
what are the directional terms for brain and spinal cord?
rostal is anterior (toward the nose)
caudal is posterior (toward the tail)
what does the central sulcus separate?
the frontal and parietal lobes
what does the parieto-occipital sulcus separate?
the parietal and occipital lobes
what does the lateral solcus separate?
the temporal lobes from the rest
what are the cerebral hemispheres?
left and right hemispheres
what are the 3 parts of the brainstem?
1) midbrain
2) pons
3) medulla oblongota
what are the 3 parts of the diencephalon?
1) interthalamic adhesion
2) thalamus
3) hypothalamus
what type of matter is the cerebral cortex made of?
grey matter
what covers most of the surface of an adult brain?
cerebral cortex
what structures protect the brain?
1) cranium
2) protective connective tissue(meninges)
3) CSF (cerebrospinal fluid)
4) blood brain barrier (glial and endothelial cells)
what are the functions of the meninges?
1) separate the brain and spinal cord from the bones
2) protect blood vessels of the brain and form some large veins that drain blood from the brain
3) contains and circulates CSF
arachnoid mater resembles what?
spider webs
how many layers does dura mater have?
2
what are the 2 layers of dura mater?
1) periosteal layer
2) meningeal layer
what are ventricles in the brain?
cavities that store CSF
how many ventricles are in the brain?
4
what is CSF?
cerebrospinal fluid is a clear liquid that circulates in ventricles and subarachnoid space
what are the functions of CSF?
1) buoyancy
2) protects brain and spinal cord by absorbing shock
3) transports nutrients and removes waste
what area of the brain is responsible for concious thought?
cerebrum
what is the corpus callosum?
largest tract that connects the two hemispheres in the brain
parietal lobe functions:
general sensory (touch, pressure, pain, temp)
occipital lobe functions:
1) processes incoming visual information
2) stores visual memories
insula location:
deep to the lateral sulcus
what does melatonin regulate?
circadian rhythm
what is the function of the thalamus?
aka relay station.
responsible for unconscious processing of what you see
what is the passageway between the cerebrum and spinal cord?
brainstem
what is the cerebral aqueduct
a passage that rxtends through the midbrain and connects the third and fourth ventricles
what does the pons help regulate?
breathing
what “centers” are in the medulla oblongotta
1) cadiac center
2) vasomotor center
3) medullary respiratory center
what is the medulla oblongotta responsible for?
1) regulating heart rate and strength of contraction
2) controlling blood pressure by regulating the smooth muscle walls of arterioles
3) regulating respiratory rate
what part of the brain regulates coughing, sneezing, salivation, swallowing, gagging, and vomitting?
the medulla oblongota
what is the second largest part of the brain?
cerebellum
what are the partitions of the cerebellum?
1) cerebellar cortex(grey matter/outter layer)
2) arbor vitae (white matter/inner region
what is folia?
the folds of the cerebellar cortex
what are the functions of the cerebellum?
1) coordinates movements
2) stores memories of previously learned movement patterns
3) adjusts muscle activity to maintain equilibrium and posture
4) uses information from muscles and joints to regulate body position
what does arbor vitae translate to?
tree of life
what system forms a ring around the diencephalon?
limbic system
limbic system functions:
1) limbic structures process and experience emotions
2) affects memory formation by integrating past memories of physical sensation with emotional states
cingulate gyrus=
part of the limbic system that brings emotions into consciousness
parahippocampal gyrus=
tissue in limbic system associated with the hippocampus that is assosiated with memory
hippocampus=
nucleus shaped like a horseshoe in the limbic system that consolidates long term memories
amygdaloid body=
part of the limbic system involved in emotion(especially fear)
helps sort memories based on emotional perception
olfactory bulbs, tract, and cortex=
part of the limbic system that can provoke emotions or memories when odors are sensed
fornix=
thin tract of white matter connecting hippocampus with other limbic structures
cranial nerves in order:
CN1 = olfactory bulb
CN2 = optic nerve
CN3 = oculomotor nerve
CN4 = trochlear nerve
CN5 = trigeminal nerve
CN6 = abducens nerve
CN7 = facial nerve
CN8 = vestibulocochlear nerve
CN9 = glossopharyngeal nerve
CN10 = vagus nerve
CN11 = accessory nerve
CN12 = hypoglossal nerve
