Week 5 Study Cards Flashcards
Nervous tissue is composed of what two principal cell populations?
neurons and supporting cells
What are other names for supporting cells?
neuroglia or glial cells
What is CNS?
central nervous system
What is PNS?
peripheral nervous system
What are neurons/ functions?
specialized cells to transmit messages from one part of the body to another
What are structures of the neurons?
cell body, nuclei, ganglia
What are the extensions of the neurons called?
processes or fibers
What is ganglia?
clusters of neuron cell bodies outside the CNS
What do neurons make up in the nervous system?
gray matter
What do the neuron processes form in the CNS?
tracts of white matter
What do the neuron processes form in the PNS?
peripheral nerves
Other than the nucleus what is the other large dot in the cell body?
nucleolus
What is the neurons cytoplasm composed of?
neurofibrils with rough ER called Nissl bodies
What are neuron processes that conduct electrical currents toward the cell body called?
dendrites
What are neuron processes that conduct electrical currents away from the cell body?
axons
How many axons do neurons have?
one
How is a neuron excited?
by signal or other neurons
What is the end of the axon called?
axon terminal
The axon terminals store what?
neurotransmitters
What is the tiny gap that separates an axon terminal and dendrites?
synaptic cleft
What is the fatty material that covers long nerve fibers?
myelin
What are myelin fibers referred to as?
myelinated
What are the special cells that mylinate the axons?
Schwann cells
How do schwann cells work?
wrap themselves around the outside of axon with nucleus on outside
What encompases the cell once the schwann cell wraps
myelin sheath
What is the myelin sheath composed of?
tight core of plasma membrane material
What is the part of the schwann cell external to the myelin sheath called?
neurilemma
What are the gaps between the schwann cells called?
nodes of Ranvier
What determines the structural classification of neuron cells?
How many processes are attached to cell body
What is a unipolar neuron?
One very short process which divides into distal and proximal that extend away from cell body
What is bipolar neurons?
one axon and one dendrite attached to the cell body
What are multipolar neurons
all are dendrites except for a single axon
What are neurons that carry impulses from the sensory receptors in the internal organs or in the skin called?
sensory, afferent neurons
What are motor or efferent neurons?
Neurons that carry activating impulses from the CNS to muscles and glands
What are interneurons or association neurons?
situated in pathways that connect sensory and motor neurons. Their cell bodies are always located within the CNS and they are multipolar
What is each fiber of a nerve surrounded by?
endoneurium
What are groups of fibers bound by?
perineurium
What do these groups of fibers surrounded by perineurium form?
fascicle bundles
What are all fascicles bound together by?
epineurium
What are neurons that carry both sensory and motor fibers called?
mixed nerves
What are nerves that only carry sensory processes and conduct impulses only toward the CNS?
sensory or afferent nerves
What are nerves that only carry motor fibers?
motor or efferent nerves
What are the two principal divisions of the nervous system?
central nervous system
peripheral nervous system
What consists of the central nervous system?
brain and spinal cord
What consists of the peripheral nervous system?
cranial and spinal nerves, ganglia, sensory receptors
What are the four major regions of the brain?
cerebral hemispheres, diencephalon, brain stem, cerebellum
What is the most superior part of the brain?
cerebral hemispheres
What is gyri?
elevated ridges of the brain surface
What separates gyri?
fissures or sulci
What fissure separates the cerebral hemispheres?
longitudinal fissure
What divides the frontal lobe from the parietal lobe?
central sulcus
What separates the temporal lobe from the parietal lobe?
lateral sulcus
What divides the occipital lobe from the parietal lobe?
parieto-occipital sulcus
Where is the primary somatic sensory area located?
in the parietal lobe posterior to the central fissure
Where is the primary motor area? What is its function?
allow us to consciously move our skeletal muscles and is anterior to the central fissure in the frontal lobe
Where is the premotor area? What is its function?
region that stores the instructions for sequences of motor activity located anterior of primary motor area
What is Broca’s area?
specialized motor speech area found at base of primary motor area above the lateral sulcus
What is the cerebral cortex?
outermost gray matter of cerebrum
What is the cerebral white matter?
fiber tracts carrying impulses to or from the cortex
What is the most superior portion of the brain stem?
diencephalon
What is cerebral peduncles?
fiber tracts in the midbrain connecting the pons below with cerebrum above
What does pons mean?
bridge
What are the pons?
consists of primarily of motor and sensory fiber tracts connecting the brain with lower CNS centers
What is the lowest brain stem region?
medulla oblongata
What does the medulla house?
vital autonomic centers involved in the control of visceral activities such as heart rate, respiratory rhythm and blood pressure
What is the structure of the thalamus?
two large lobes of gray matter that laterally enclose the shallow third ventricle of the brain
What is intermediate mass/ function?
stalk of thalamic tissue, connecting two lobes and spans the ventricle
What is function of thalamus?
relay station for sensory impulses passing upward to the cortical sensory areas
What makes up the third ventricle?
hypothalamus
What is the function of the hypothalamus?
important autonomic center involved in body temperature regulation and water balance
Where is hypothalamus located?
pituitary gland
What is the mamillary bodies?
relay stations for olfaction, bulge exteriorly from the floor of the hypothalamus just posterior to the pituitary gland
What forms the roof of the third ventricle?
epithalamus
What are important structures of the thalamus?
pineal gland and choroid plexus
What is the cerebral aqueduct?
slender canal traveling through the midbrain, connects the third ventricle to the fourth ventricle in the pons and medulla below
What is the treelike branching of the cerebellar white matter
arbor vitae
What are the connective tissue membranes that cover and protect the brain?
meninges
What is the outermost membrane?
dura mater
The dura mater has two layers what are they?
periosteal layer and meningeal layer
The dura mater is fused together except for three areas such as one fold that hold it in place in skull. What is name of fold?
falx cerebri
Where does falx cerebri attach?
to the crista galli of the ethmoid bone of the skull
What is the cavity created by the falx cerebri attachment?
superior sagittal sinus
What is the middle membrane?
arachnoid mater
What space separates the arachnoid and dura mater?
subdural space
The subdural space has threadlike projections that bridge into what?
subarachnoid space
Where do the threadlike projections attach?
pia mater
What is the subarachnoid space filled with?
cerebrospinal fluid
What are the specialized projections of the arachnoid tissue called?
arachnoid villi
Where doe the arachnoid villi protrude/ attach?
through dura mater to allow the cerebrospinal fluid to drain back into the venous blood via the superior sagittal sinus
What continually forms the cerebrospinal fluid?
choroid plexuses
What are the choroid plexuses?
small capillary knots hanging from the roof of the ventricles of the brain
What is the function of cerebrospinal fluid?
watery cushion that protects the brain tissue against blows to the head
What system are the cranial nerves apart of?
peripheral nervous system
How many pairs of cranial nerves are there?
12
What is considered a continuation of the brain?
spinal cord
What is the spinal cord enclosed in by?
vertebral column
Where does the spinal cord extend?
foramen magnum of the skull to the first or second lumbar vertebrae
What cushions and protects the spinal cord?
meninges
How many pairs of spinal nerves arise from the spinal cord?
31 pairs
What is the collection of spinal nerves at the inferior end of the vertebral column?
cauda equina
What is the part of the spinal cord that looks like a butterfly or an H?
gray matter
What are the two posterior protrusions of the gray matter called?
dorsal horns
What are the two broader anterior projections of the gray matter called?
ventral horns
What is the lateral outpocketing of gray matter in the thoracic and lumbar regions of the cord?
lateral horns
The central gray matter surrounds what?
central canal
What is contained in the central canal
cerebrospinal fluid
Where do association neurons and sensory fibers enter the cord?
dorsal root of the dorsal horn
the cell bodies of these sensory neurons are found in what enlarged area of the dorsal root?
dorsal root ganglion
The ventral horns contain cell bodiest of motor neurons that exit through what?
ventral root
What is the small area where ventral and dorsal roots combine before splitting off?
spinal nerves
What is the white matter of the spinal cord composed of?
myelinated fibers
White matter is divided into three regions, what are they?
posterior
lateral
anterior columns
What does each white column contain?
fiber tracts
What are fiber tracts?
axons with the same origin, destination, and function
What are dorsal and ventral rami?
the divisions right after spinal nerve
The ventral rami of all other spinal nerves forms what complex nerve network?
plexuses
When the ventral rami of spinal nerves T2-T12 pass anteriorly what do they form?
intercostal nerves
What is the cervical plexus?
arises from the ventral rami of c1 through c5 and supplies muscles of the shoulder and neck
What is the major motor branch of this plexus?
phrenic nerve
Which vertebrae ventral rami roots form phrenic nerve?
C3-C5
What nerve arises from the ventral rami of C5-C8 and T1
brachial plexus
The brachial plexus divides into what?
5 major peripheral nerves
What nerve serves the muscles and skin of the shoulder?
axillary nerve
What is the radial nerve?
passes down the posterolateral surface of the limb supplying all the extensor muscles of the arm forearm and hand and the skin
What is the median nerve?
passes down the anterior surface of the arm to supply most of the flexor muscles in the forearm and several muscles in the lateral part of the hand
What is the musclocutaneous nerve?
supplies the arm muscles that flex the forearm and the skin of the lateral surface of the forearm
What is the ulnar nerve?
travels down the posteromedial surface of the arm, supplies the flexor carpi ulnaris and all intrinsic muscles of the hand not served by the median nerve
What is the lumbar plexus?
arises from ventral rami of L1 through L4 and serves the anteromedial thigh and lower abdominal region
What is the largest nerves of the lumbar plexus?
femoral nerve
What is the femoral nerve?
innervates the anterior thigh muscles
What is the sacral plexus?
arises from L4 and S4 and supply the buttock and posterior thigh and virtually all of the leg and foot
What is the major nerve of the sacral plexus?
sciatic nerve
What is the sciatic nerve?
largest nerve in the body, travels through the greater sciatic notch and down the posterior thigh serving its flexor muscles and skin
What does the sciatic nerve divide into?
common fibular nerve and tibial nerve
What does the common fibular nerve and tibial nerve supply
the balance of the leg and foot
