What are the nonmyelinated portions of the axon called?
Nodes of Ranvier
What is it called when conduction jumps from one node to another??
What are the smallest neuroglial cells?
Which glial cells are scattered all throughout the CNS and function at the sites of injury or sites of degeneration?? At these sites they proliferate and develop into large macrophages that phagocytize neuronal debri..
**their job is to get rid of debri
Which cells line the roof of the 3rd and 4th ventricles of the brain and the central spinal canal?
What do ependymal cells secrete?
Which cells form the cuboidal epithelium aka the choroid plexus?
What is the purpose of the Blood Brain Barrier?
to isolate the brain and spinal cord from the rest of the body
What areas of the brain lack the BBB?
area of postrema, pituitary gland, pineal gland, choroid plexus and portions of the hypothalamus
** these areas receive neurosecretory products from the blood
Which cells are said to prevent hemorrhagic strokes?? or hemorrhage in general?
What word would you use to describe the BBB of a newborn?
**things can get to newborns that can't get to us because of immunity... newborns have not built up an immunity yet
What are a collection of dense cell bodies in the CNS called?
What are a collection of cell bodies outside the CNS called?
When BBB disruption occurs because of trauma, hemorrhage or ischemia, what happens?
substances that normally would not be able to can penetrate the BBB and get to the brain
The cerebral hemispheres contain what 4 parts?
1. cerebral cortex
2. hippocampal formation
4. basal ganglia
The surface of the cerebral cortex is convoluted..what does this mean?? and why is it like this?
it has lots of wrinkles
these wrinkles work to increase the surface area
Gyri refers to what??
the elevated part of the cerebral cortex
Sulci refers to what?
the grooves in the cerebral cortex that separate the gryi (or elevated portion)
What are the fissures in the cerebral cortex?
the deeper groves noted on the surface
The medial longitudinal fissure divides ___________.
the cerebral hemispheres into right and left halves
The lateral fissure of Sylvius and central sulcus of Rolando divide __________.
the hemispheres into 4 lobes.
How are the lobes in the brain named?
by the parts of bone that lie above them
The central sulcus separates ______ and ______lobes.
frontal and parietal
What is the frontal lobe essential for?
What is the parietal lobe essential for?
senses of pain and touch
The cerebral cortex is divided into _____ areas called _____.
Voluntary muscle movement is controlled in which gyrus?? What Brodmanns area is this?
In the precentral gyrus or Brodmanns area 4
What makes up the primary somatosensory area 1 also called the cortex? ie...what Brodmanns areas are involved to make up the somatosensory area 1?
Brodmanns areas 1, 2, 3
Brodmann's areas 5 and 7 function as the _________.
somatosensory association area
Which gyrus is the control area of sensation of touch, pain, and limb position?? also..which lobe is this are in???
in the post-central gyrus of the parietal lobe
The temporal lobe contains the ______ cortex.
The temporal lobe is separated from the frontal and parietal lobes by the ____ fissure.
Where does the occipital lobe lie?
posterior to the parietooccipital sulcus
Which lobe of the brain houses the visual cortex?
The visual cortex lies within the wall of the _______ fissure on the medial brain surface.
Where does the corpus callosum lie?
deep in the long fissure
The fibers of the hemispheres are located where?? and what do they do??
they interconnect the hemispheres
The basal ganglia are involved with???
the control of movement
The amygdala functions in relation to what 3 things???
response to pain and appetite
response to stress
The hippocampal formation is essential for _____ and _____.
memory formation and learning
Where is the diencephalon located? What does it contain?
midline between the hemispheres
contains the thalamus and hypothalamus
What does the thalamus do??
The thalamus integrates and transmits sensory information to various cortical areas of the cerebral hemispheres.
The hypothalamus is also known as ____.
the MASTER neurohormonal organ
What four things are controlled in the hypothalamus?
b. ADH-water balance
c. Temperature control
d. Sleep function
What 3 things form the brainstem?
midbrain, pons, and medulla
The brainstem functions to maintain what 3 things via the reticular activating system?
The pons is ____ to the cerebellum. It is separated by the 4th ventricle. It connects the ____ to the ____.
1st blank -- Anterior
2nd blank -- medulla oblongata
3rd blank -- midbrain
The pons contains ascending and descending fiber tracts and the nuclei of the ____ and ___ nerve.
trigeminal (5th CN)
and facial (7th CN)
What extends from the pons to the foramen magnum?
The medulla contains what 2 control centers?
Respiratory and Cardiovascular control centers
What nuclei (aka nerves?) are located in the medulla??
vestibulocochlear nerve (8)
spinal accessory nerve (11)
hypoglossal nerve (12)
The outer part of the cerebellum is what color?? what color is the inner part?
gray on the outside
and white on the inside
Where does the cerebellum lie?
below the occipital lobe and behind the pons and medulla
Name the 3 functional areas of the cerebellum?
Which part of the cerebellum function areas is the largest?
Which part of the cerebellum's functional areas controls the coordination of muscle activity?
What part of the cerebellum's functional areas maintains equilibrium?
What part of the cerebellum's functional areas regulates muscle tone?
What is the main job of the cerebellum?
to integrate information to the lower motor neurons involved in maintenance of muscle tone, equilibrium, and voluntary muscle activity
The brain and spinal cord are covered by what 3 meningeal layers?
1. Dura mater
2. arachnoid mater
3. pia mater
What does the dura mater form? The dura mater is also known as???
1. forms falx cerebri (fold that seperates the cerebral hemispheres)
2. tough mother (it is the thickest layer)
Where is the subarachnoid space? Where does it end?
between the arachnoid and pia mater
ends at S2 and S3
Where is the epidural space?
the space is located outside the dura but inside the spinal canal
The spinal cord extends from the ____ to the ____.
medulla to the filum terminale
The dorsal white matter of the spinal cord is composed of ______.
ascending sensory fiber tracts.
**contains afferent nerves that carry impulses towards the CNS
The lateral and ventral white matter of the spinal cord contain ___________.
descending motor tracts.
**contains efferent nerves that carry impulses away from the CNS
The spinal cord is divided into regions by the entering dorsal sensory nerve roots and the outgoing ventral nerve routes.. what are these 3 regions?
dorsal, lateral, ventral
The central core of the spinal cord is what color?
A cross section of the spinal cord reveals a ___ shape??
List the cranial nerves..which ones are sensory, motor or mixed?
–XI-Spinal accessory (motor)
____ cervical spinal nerves
____thoracic spinal nerves
____ lumbar spinal nerves
____ sacral spinal nerves
_____coccygeal spinal nerves
Where do the first pair of cervical nerves exit the spinal cord??? Where do all the other nerve pairs exit the spinal cord?
1. between the base of the skull and the first cervical vertebra (atlas)
2. remaining pairs exit between adjacent vertebrae
T4 is considered to be at the level of the _____.
T10 is considered to be at the level of the _____.
Except for C1, each spinal nerve receives sensory input from specific areas called ______.
All the exiting spinal nerves are covered by ____.
Because the spinal cord is shorter than the vertebral canal in adults, the ____ and ___ nerves have ______ (short or long) roots. These roots are called ______.
1st blank -- lumbar
2nd blank -- sacral
3rd blank -- long
4th blank -- cauda equina
Where does the spinal cord end in correlation with the vertebrae?
The right and left sides of the spinal cord core are connected by gray commissure. What is the middle of this commissure called?
The core of the spinal cord consists of two ___ and two thicker ____.
dorsal horns (posterior)
and two thicker ventral horns (anterior)
Intermediolateral gray horns or columns of the spinal cord and found between ______ and ___.
T1 and L2
The gray matter of the spinal cord is subdivided into 10 laminae of Rexed which are similar to Brodmann's areas in the brain. Rexed Laminae areas 1 through 6 are located where??? and what do they do?
in the Dorsal horn (posterior)
they receive sensory information
Laminae 5, 6, and 10 contain a large number of _____.
Projections form the Laminae form _______ _____.
Laminae 7, 8 and 9 make up the ____ ___. They contain motor neurons and interneurons that are involved in _____.
ventral horn (anterior)
The gray matter of the spinal cord contains 2 enlarged areas... where are these areas located in relation to the vertebrae?
1. C5-C7 CERVICAL AREA INNERVATES UPPER EXTREMITIES
2. L3-S2 LUMBAR AREA INNERVATES LOWER EXTREMITIES
Each spinal nerve has two points of attachment to the spinal cord...what are these two points?
The dorsal root and ventral root.
When the dorsal and ventral roots of the spinal nerves attach to the spinal cord they divide into what???
6-8 rootlets that enter the spinal cord
Distal to the dorsal rootlets at spinal cord are swellings called ____ _____ ____. What do they contain?
dorsal root ganglion
they contain somas of afferent neurons
The nerves that exit the spinal cord through the intervertebral foramen divide into what 3 areas?
Dorsal ramus, ventral ramus, small meningeal branch
What does the dorsal ramus innervate muscles and joints?
in the region of the spine and the skin of the back
What does the ventral ramus innervate?
innervates ventral and lateral skin and muscles of the trunk and gives rise to the nerves in the limbs
What does the small meningeal branch of nerves do?
it reenters the vertebral canal and innervates the meninges, vertebrae and spinal ligaments
The outermost covering of the peripheral nerves is called the __________. The bundles or fascicles of axons in each nerve are covered by the ________, and each axon in a fascicle is surrounded by the ____________.
1st blank -epineurium
2nd blank -perineurium (covers a bundle of nerves)
3rd blank -endoneurium (covers each neuron)
Peripheral nerves are classified according to their diameter. A alpha means they have the _____ diameter.
C fibers are the _________ and __________ nerve fibers.
smallest and slowest
Put these fibers in order based on which is the largest...
A delta, B, C, A beta, A alpha, A gamma
1. A alpha
2. A beta
3. A gamma
4. A delta
Somatic muscle fibers arise from the motor neurons in the ________ ________. They exit the spinal cord via the ____ ________.
When motor neurons join with sensory neurons what is formed?
a mixed nerve
**when the mixed nerve approaches the site of innervation, the motor and sensory fibers will separate to do their job
What are 4 things to remember about reflexes?
1. they require stimulation to elicit a response
2. they occur quickly
3. they are involuntary
4. they are stereotyped..they do the same thing everytime!!!!
Afferent nerve fibers are found on ______ nerve tracts.
ascending... carry something to the CNS
Efferent nerve fibers are on _______ nerve tracts.
descending....they carry away from CNS to muscle
What role does the skeletal muscle play in reflex arcs?
the muscle carries out the reflex
What is the stretch reflex?
the reflex that only allows your muscles to stretch so far and then they fight back to maintain equilibrium and posture.
A stretch reflex forms a ____ reflex arc which means it involves ____.
monosynaptic reflex arc which means it only involves 1 synapse
What is an example of a stretch reflex?
patella tendon reflex
What is the flexor withdrawal reflex?
ex. hand on a hot stove.. you automatically jerk back
is it the quick contraction of flexor muscles resulting the withdrawal of a limb from an injurious stimulus
The flexor withdrawal reflex forms a ______ reflex arc which means it involves _____.
polysynaptic ---many synapses
What occurs with the flexers and extensers in the affected limb with the flexor withdrawal reflex?
the flexers will contract and the extensions will relax in the threatened limb.
Explain what occurs with the crossed extensor reflex?
After a stimulus elicits a flexor reflex in one limb, the other limb begins to extend to maintain balance and to allow the body to push itself away from the painful stimuli.
---contralateral reflex--- sensory data is received on the opposite body part than the one in pain
Ascending spinal tracts carry sensory information ____ the spinal cord.
Descending spinal tracts carry sensory info ___ the spinal cord.
Sensory signals travels across 3 neurons in the ascending spinal tracts from their origin to the destination. What does the first order neuron do with the signal?? What about the 2nd and 3rd order neurons?
The first order neuron detects stimuli and transmits it to the spinal cord or brain stem.
The 2nd and 3rd order neurons continue to carry the signal to the sensory area of the cerebral cortex... (the 2nd goes to the thalamus and then the 3rd carries it the rest of the way).
Pain, temperature, and crude sensations travel via the ______ and _____ ________ ______.
anterior and lateral spinothalamic tracts.
Vibration, proprioception and fine tactile sensations travel via the _____ or the ____ ____ ____.
dorsal column or the medial lemniscal system
Which spinal tract supplies the voluntary muscles of the head and neck??
**this tract carries motor signals from the cerebral cortex for finely coordinated limb movements
**remember this is a descending nerve tract
What arises from the brain and spinal cord and transmits efferent signals to the smooth muscle, cardiac muscle and some glands?
autonomic preganglionic fibers
What part of the cardiac output does the brain receive?
15% or approx. 50ml/100g/min.
The brain is equal to what % of the body weight?
What two systemic arteries supply blood to the brain??
the anterior receives blood from the carotids
the posterior receives blood from the vertebral arteries.
The two arterial systems of the CNS communicate via the _____ __ _____.
circle of willis
Where do the anterior, middle and posterior cerebral arteries originate from?
Circle of Willis
Which artery bifurcates to form the anterior and middle cerebral arteries?
internal carotid artery
What does the anterior cerebral artery of the brain supply?
the medial surface of the cerebral hemisphere
What does the middle cerebral artery supply within the brain?
the lateral surface of the hemisphere
What do striate arteries branch from and what do they supply?
branch from the middle cerebral arteries... supply the internal capsule and motor tracks.
Where do the vertebral arteries branch from and what do they form??
branch from the subclavian artery...they form the basilar artery
these arteries supply a wide area of the brain**
Venous blood will drain from the brain via what two systems?
dual venous sinuses and the great vein of Galen and the straight sinus
Which two arteries supply the spinal cord??
Anterior spinal artery --supplies anterior 2/3 of spinal cord
Posterior spinal artery --supplies posterior 2/3 of spinal cord
The cervical cord is supplied by the ____ and ___ arteries.
Vertebral and radicular arteries
The thoracic and lumber spinal cord are supplied by the _____ arteries.
What supplies the lumbosacral segment of the spinal cord?
Artery of Adamkiewicz
In 75% of patients the Artery of Adamkiewicz arises on the left side of the aorta between ___ and ____.
T8 and L1
The neuron that is sending info is called the ____ neuron. What do these neurons release?
The neuron that receives info is the ____ neuron.
If a neurotransmitter is said to be excitatory it will increase the permeability to???
If a neurotransmitter is said to be inhibitory it will increase the permeability to???