Exam 5 Flashcards
What do nervous system functions include?
Sensory functions
Integrative
Motor planning
Which division of the nervous system is responsible for brain and spinal cord?
CNS
Which division is responsible for nerves and ganglia?
PNS
What are 3 physiolgical properties of a neuron?
Excitability, conductivity, secretion
Sensory Afferent neurons ..,,
Detect stimuli
Interneurons (association neurons) …
Receive signals from other neurons and make decisions about response
Motor (efferent) neurons…
Send signals to muscles to provide response
What is the control center of the neuron?
Neurosoma
What had compartmentalized ER?
Nissl bodies
What part if the neuron receives signals?
Dendrites
What part if the neuron sends action potentials?
Axons
What is the complex of branches at axons distal end?
Terminal arborization
What is the ending of an axon branch that communicates with another cell?
Synaptic knob
A neuron with many dendrites, one axon?
Multipolar
A neuron with one dendrite, one axon?
Bi polar
A neuron with no dendrites and has one axon?
Unipolar
A neuron with many dendrites and no axons?
Anaxonic
Of the CNS glia, Oligodendrocytes do what?
Myelinate to assist conductivity
What do the ependymal cells do?
Secrete and circulate cerebrospinal fluid
Why do microglia do?
Help in defense and disposal
What do astrocytes do?
Provide support and nourishment
Of the PNS glia, what does the Schwann cells do?
Myelinate to assist conduction
What do the satellite cells do?
Provide support and nourishment
What makes up the fatty white matter of CNS?
Oligodendrocytes
What are fiber segments covered by myelin?
Internodes
What are fiber segments with gaps in myelin?
Nodes of ranvier
What is the outermost layer of a Schwann cell?
Neuralemma
Signal conduction speed depends on two factors:
Diameter of fiber (larger = faster)
Presence it myelin (myelinated are fster)
Cut nerve fibers can regenerate if what?
Nerve cell bodies remain intact
Which cells secrete nerve growth factors?
Schwann cells
Can CNS neurons regenerate?
No
Meeting point of neuron and other cell?
Synapse
Adjacent cells joined by gap junctions
Ions diffuse from cell to cell
Quick transmission
No integration or decision-making
Electrical Synapse
What are the first embryonic traces of CNS?
Neural plate
Neural groove with neural folds
By 4 weeks, a hollow channel is created known as the what?
neural tube
The neural tube has three anterior bulges;?
Forebrain, midbrain and hindbrain
What happens in the 5th week of development?
Secondary vesicles
Which neural tube defects affects one to a few vertibrae and causes no functional problems?
Spina bifida occulta
Which neural tube defect is more severe and causes a sac to protrude from spice?
Spina bifida cystica
In what NTD causes a small brain?
microcephaly
In what NTD causes no brain
anecephaly
What bypathologist removed Albert Einsteins brain after 7 hours of deat?
Thomas Stoltz Harvey
What was found in Albert Einsteins brain that could have enabled his intelligence?
increased number of glial cells
What forms myelin in the spinal cord?
Oligodendrocytes
The automic nervous system is also called the?
visceral motor division
What divivsion tends to prepare the body for action?
symoathetic
Nerves are _____ of the organ system?
organs
What are examples of effectors of the nervous system?
Glands
What division carries signals to the smooth muscle in the large intestine?
visceral motor
About 90% of the neurons in the nervous system are what?
Association
WHat are the most common type of neurons?
Multipolar
The myelin sheath is formed by?
cells
The mechanism by which nervous system converts these action potentials into meaningful information is called neural _____?
coding
What are four functions of the spinal cord?
Conductivity
Neural integration
Locomotion
Reflexes
Sensory information _____ in the spinal cord.
Ascends
Motor function ________ in the spinal cord.
Descends
What is neural integration?
Processing of info from diverse sources
Why is locomotion?
Central patterns generators coordinate simple repetitive movements
What is an involuntary stereotyped response to stimuli?
Reflexes
What are the regions of the spinal cord?
Cervical
Thoracic
Lumbar
Sacral
Spinal enlargements are in which two regions?
Cervical and lumbar
Tough outer layer; epideral space
Dura mater= dura sheath
Middle layer; subarachnoid space with cerebral spinal fluid.
Arachnoid matter
Delicate inner layer; coccygeal and denticulate ligaments
Pia matter
-What contains little myelin –Two posterior (dorsal) horns –Two anterior (ventral) horns –Two lateral horns within thoracic and lumbar regions –Connected by a gray commisure
Gray matter
–Myelinated axons
–Three pairs of columns (funiculi). Each column is divided in tracts (fasciculi)
•Posterior (dorsal), lateral, and anterior (ventral) columns
White matter
What do ascending tracts do?
carry sensory info to brain, whereas descending tracts carry motor info from brain
Many tracts cross the midline at a what?
Decussation
If a tract crosses the midline then it’s origin is ____ to it’s destination.
Contralateral
If a tract does not cross midline then it’s origin is _______ to it’s destination?
Ipsilateral
What does the1st order neuron do?
conducts the stimulus to the spinal cord or brainstem.
What does the 2nd order neuron do?
conducts the stimulus to the thalamus (at the upper end of the brainstem)
What does the 3rd neuron do?
Conducts the stimulus to cerebral cortex
Which tract carries signal from the midthoracic and lower parts of the body?
gracile fasciculus
which tract joins the gracile tract at T6 and carries signals from the upper limbs and chest?
Cuneate fasciculus
Both ascending posterior column tracts contain what?
1st order neurons sensing body position, discrimitive touch, and pressure on the side of the body
What tract ascends in the anterior and lateral columns to end in the thalmus?
spinothalamic tract
What does the spinothalamix tract contain?
second order neurons sensing pain, temperature, tickle, itch, and light and crude touch from contralateral sensory neurons
What lacks the fine discrimination and doesnt generally give enough info to the brain to enable it ro recognise a familiar object by touch alone?
Crude (protopathic) touch
What does the spicoreticular tract do?
carries pain signals from tissue injure
Corticospinal tracts carry signals for precise limb movements from what?
motor cortex ( upper motoe neurons)
What do descending tracts do?
carry motor signals down the brainstem and spinal cord.
The upper neuron of the descending tract has what?
the soma in the cerebral cortex
The lower motor neuron contains what?
the axon in the brainsem or spinal cord
Where does the axon of the lower motor neuron end?
in the muscle or target organ
What is a nerve?
several axons wrapped by connective tissure
Endoneurium wraps what?
one axon
Perineurium wraps what?
a fascicle of axons
Epineurium wraps what?
entire nerve
Carry sensory signals from receptors to the CNS
Afferent fibers
Carry motor signals from the CNS to effectors
Efferent fibers
Innervate skin, skeletal muchles, bones, and joints?
Somatic fibers
Innervate blood vessels, glands, and viscera
Visceral fibers
Innervate widespread organs such as muscles skin, glands, viscera, and blood vessels
General fibers
Innervate more localized organs in the head, including the eyes, ears, olfactory and tase receptors, and muscles of chewing, swallowing, and facial expression
Special fibers
What is a ganglion?
a cluster of cell bodies outside the CNS
How many pairs of spinal nerves are there?
31
How many of each spinal nerves are in each region of Thoracis, lumber, sacral, coccygeal?
12,5,5,1 respectively
what do plexuses do?
receive fibers from anterior rami and give rise to peripheral nerves
The Cervical plexus is?
in neck
the brachial plexus is in?
shoulder
the lumbar plexus is in
lower back
the sacral plexus is
below lumbar
the coccygeal plexus is
lower sacrum and coccyx
What is a dermatome map?
diagram of the areas of skin innervated by each spinal nerve
Each spinal nerve except ______ receives a sensory input from a specific area of skin called dermatome?
C1
How is spinal nerve damaged assesd?
By testing the dermatomes, by pinpricks and noting the areas where the patient has no sensation
What are properties of a reflex?
requires stimulation
quick
involuntary
stereotyped
What is a visceral reflex?
Glans. cardiac muscle. and smooth muscle
controlled by autonomic nervous system
What is a somatic reflex?
Skeletal muscles
controlled by somatic nervous system
What is an ipsilateral reflex?
sensory input and motor output on same side
What is a contralateral reflex?
sensory imput from opposite side as motor output
What is intersegmental reflex?
sensory signal in one lever; motor output at a higher or lower level
syndrome of paralysis and absence of reflexes after transection of cord
Spinal shock
dangerous drop in blood pressure due to lack of sympathetic nervous system activity
Neurogenic shock
– paralysis of both lower limbs due to lesions from T1 to L1
Paraplegia
paralysis of all four limbs due to lesions above C5
quadriplegia
paralysis on one side of body usually due to stroke or brain lesions
Hemiplegia
The Brain si divided kinto 3 major regions: ?
Cerebrum, Cerebellum, and brainstem
Which region of the brain consists of two cerebral hemispheres, gyri (folds), and a longitudal fissure?
Cerebrum
Which region of the brain is marked by gyri, sulci, and fissures?
Cerebellum
Which region of the brain is the smallest of all and its major components are the diencephalon, midbrain, pons,and medulla oblongota. This part of the brain is crucial for survival
Brainstem
What is the outer part (cortex) of cerebrum and of cerebellum, as well as deep nuclei. It is the site of the neurosomas, dendrites, and synapses.
Gray matter
Deep in the brain and is composed of tracts or bundles of myelinated axons
White Matter
Within the cranium the dura mater has two layers: ?
Periosteal layer and meningeal layer
In some places, the layers separate to form dural sinuses. These sinuses are?
Superior sagittal sinus and Transverse sinus
In some places, dural sheets occupy spaces separating majr parts of the brain. What are these called and which parts do they separate?
Falx cerebri separate between hemispheres
Tentorium cerebelli separate between cerebrum and cerebellum
What are the three meninges?
Dura matter - yough, outer layer
Arachnoid mater - transparent, middle layer
Pia mater - delicate, inner layer
