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Anatomy 224 Exam 1

Terms in this set (38)

The ______ tract carries descending information from the primary motor cortex
corticospinal/pyramidal
Name the meninges in order from inside to outside
Pia, arachnoid, dura
the primary auditory cortex is located in the
temporal lobe
during repolarization phase of an action potential, _______ ions cross the membrane from the ________ to the _______
K+; cytosol; interstitial fluid
Neuroglia found in the CNS that bind axons and blood vessels to each other are called
astrocytes
Which white matter tracts connect the cerebrum to the lower brain areas
projection fibers/pyramidal
The ____________ is a neuroendocrine structure that regulates body temperature and hunger and plays a role in emotional responses
hypothalamus
Injury to a spinal nerve would cause ________ paralysis
flaccid
Cerebrospinal fluid leaves _______ ventricle and enters into the ______ ______ to circulate around the spinal cord and brain
fourth; subarachnoid space
Sonny was involved in an accident that left him unable to feel pain in his left leg even though he could move his left leg and feel the touch of a feather on his left foot. Select the statement that best explains Sonny's symptoms
Sonny suffered a partial tear to the right side of the spinal cord
Where will you find cerebral spinal fluid associated with the spinal cord
between the arachnoid and pia
The part of a neuron that normally receives stimuli is called a(n)
dendrite
An individual who could trace a picture of a bicycle with his or her finger but could not recognize it as a bicycle is most likely to have sustained damage to the
visual association area
Saltatory conduction occurs in
myelinated axons
What symptoms would you expect if a patient tore the ventral root of spinal nerve L1 on the left side
loss of voluntary motor control to a region of the left hip
Oligodendricytes are functionally similar to
schwaan cells
Flaccid paralysis suggests injury to
lower motor neurons
The sodium - potassium pump
pumps three sodium ions outside the cell and two potassium ions inside
The vital centers that control heart rate, respiration and blood pressure are located in the
medulla
Two terms for the massive motor tracts serving voluntary movement are
pyramidal and corticospinal
After a severe fall, Maria noticed that she could not feel pain, temperature, or discriminative touch in the palm of her right hand. However she retained her fine motor control and strength in her hand Select the statement that best explains Maria's injury
Maria tore a dorsal root on the right side
Cell bodies of the sensory neurons of the spinal nerves are located in
the dorsal root ganglia
The lobe containing the auditory cortex is separated from the premotor cortex by the
lateral sulcus
At what membrane voltage do neuronal voltage - gated Na + channels become activated
-55mV
Which of the following best describes the symptoms if a person experienced a partial injury to the right side of the spinal cord at about T12
loss of pain and temperature in the left leg
How can acetylcholine stimulate smooth muscle in the gut but slow heart rate rate
presences of different cholinergic receptors determine the tissue response
Collections of neuronal cell bodies inside the central nervous system are called
nuclei
All processing of sensory stimuli at the circuit level going up to the perceptual level must synapse in the
thalamus
If the ventral root of a spinal nerve were severed, what would be the result in the tissue or region that nerve supplies
a complete loss of voluntary movement
Ridges of tissue on the surface of the cerebral hemispheres are called
gyri
Regarding the language centers
An injury to Wernicke's area diminishes the ability to interpret written language
The period after an initial stimulus when a neuron is less sensitive to another stimulus is the
relative refractory period
An Emergency Room physician performs an initial test on a patient who was involved in a severe automobile incident. The physician started by poking the bottom of the right foot and the bottom of the left foot with sharp tack (how cruel and painful!). The patient responded when poked on their right foot but not when poked on the left foot. The physician then poked the top of the left foot and then poked periodically ascending on the left leg and torso until the patient responded when poked around the 12th rib. Answer the following questions in order and briefly explain your answer. Your answer does not have to be in essay format.
A. Would this injury impact upper and/or lower appendages?
B. Is this an injury to the nerve, nerve root (dorsal or ventral), spinal cord (complete or incomplete), brain?
C. Would this injury cause loss of sensory to the left foot? Right foot?
D. Would this patient lose motor to the left foot? Right foot?
a. lower appendages (trunk) using the dermatome the patient could sense upper thoracic regions suggesting injury in mid thoracic spinal cord which innervates the trunk
b. partial spinal cord injury - no head injury means that the injury is to a lower structure. Loss of pain to left but not right legs means the injury is not complete.
c. yes-loss of pain, temp, and crude touch (spinothalamic) to left. yes- loss of discriminative touch and proprioception to the right foot. A. Spinothalamic pathway for left foot travels on right side of spinal cord. Loss of spinothalamic pathway to left foot indicates injury on Right side of spinal cord. DCML and spinocerebellar pathway for right foot also travel in right side of spinal cord and would be lost.
d. left - no, right - yes. corticospinal travels on the same side once it gets into the body so an injury to the right side means loss of motor on the right side
We know that neuronal pathways transmit sensory and motor information to and from the central nervous system. These neuronal pathways each consist of multiple neurons in series. Explain how a graded potential in a second order neuron can lead to the production of a graded potential in a third order neuron
graded potentials sum to raise membrane potential to threshold in the axon hillock in the second order neuron. The axon hillock generates action potential that propagates down the axon and triggers the secretion of neurotransmitters. these then diffuse across the cleft and bind to a receptor. Receptor changes shape and permits ions to cross the membrane creating a graded potential on the third order neuron.
Explain why an injury to vertebra L4 is less likely to cause paralysis than an injury to T4
the spinal cord ends at L1, so at L4 there is no spinal cord to injure unlike at T4
Susan volunteered for a study trying to understand how people can perceive their environment. Study participants were led into a small, quiet room with an examination table where the subjects remove their socks and shoes, and then the subjects were blindfolded and then laid down on the exam table assuming the anatomical position. The researchers used a blunt glass probe to apply a tactile stimulus to the hands and feet of the study subject. In accordance with ethical protocols, the researchers did not provide a painful stimulus.
A. Based on material covered in class, explain how Susan could distinguish the sensations of a gentle touch on her left pinky finger versus a gentle touch (of equal intensity) on her left pinky toe.
B. Second, explain how Susan could distinguish between a gentle pressure and moderate pressure applied to her left index finger
A. the side of the brain and region of somatosensory cortex as mapped by the homunculus indicates the location of the stimuli
B. The frequency of impulse transmission indicates stimulus intensity (rate coding)
Not all stimuli are passed onto your brain. For example, you most likely have not thought about the clothes on your back even though they are activating touch receptors. Consider the following scenario: A third order neuron has synapses from hundreds of second order neurons. During a test, we see that all of the second order neurons have action potentials. Despite the stimulation by the second order neurons, the third order neuron fails to secrete any neurotransmitter. There was no intervention to alter the activity of the neurons. Provide a probable explanation why the third order neuron did not secrete any neurotransmitter
All motor neurons secreted neurotransmitter creating IPSPs and membrane potential did not reach threshold,
motor neurons all secreted neurotransmitter creating EPSPs but membrane potential did not reach threshold,
motor neurons secreted neurotransmitter creating a combination of EPSPs and IPSPs. The resulting GPs summed to be less than threshold
Mrs Smith awoke unable to speak or voluntarily move her right arm and leg. She had no other motor or sensory deficits. Discuss the severity and approximate location of the injury. Would Mrs Smith experience any other symptoms? Justify all of your answer
Mrs Smith experienced a stroke to the motor cortex regions (accept primary or premotor cortex) of the left cerebral hemisphere including Broca's Area. Hemiplegia is consistent with primary motor cortex injury. No apparent injury to the somatosensory area since no sensory was lost
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