Brain Structure Flashcards
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Q - Which of the following UMN signs is also known as the Babinski reflex?
A. Clonus
B. Hypertonia
C. Extensor Plantar Response
D. Hyperreflexia
C. Extensor Plantar Response.
True or false: Skeletal muscles are controlled by lower motor neurons.
True.
Which of the following is NOT a function of the reticular formation?
A. Autonomic Functions
B. Higher functions of the nervous system
C. Memory
D. Sleep/wakefulness cycle regulation
C. Memory is the major function of the hippocampus
With patients diagnosed with Alzheimer’s disease, what is one notable macroscopic characteristic of their brain structure?
The presence of increased deterioration of grey matter. Therefore these individuals will suffer from lots of memory problems and daily living functions. The severity of either will be dependent on the severity of the diagnosis.
Why is hydrocephalus more common in children than in adults?
Due to the lack of fusion of cranial bones yet, the dysregulation of CSF can cause the meninges to swell up instead of down (seen in adults). This can be a fatal disease without treatment.
Surgical separate of the corpus callosum is the diagnosis of:
A. Disconcord Sign
B. Discontingency Syndrome
C. Connection Sign
D. Disconnection Syndrome
Disconnection Syndrome - is the disagreement in what the left and right side of the body are perceiving
True or false 20% of children and adults are diagnosed with dyslexia.
False, Up to 15 % of children and adults are diagnosed with dyslexia
True or false: Strokes tend to be on one side of the brain, hence why the signs of a stroke always occurs on the opposite side of the brain
True. it is very rare to have two strokes in both the right and the left.
Why would the sign of pain as a result of moving the head closer to the chest result in pain be included in the meningitis?
This stretch also stretches the meninges, which will cause some pain if there is swelling and infection.
An athlete checks into the ER and complains of a headache after bumping his head after he was tackled during practice. He noted that his helmet fell off during this incident as well. What signs should you be looking for? What is his potential diagnosis?
Signs involving a concussion such as vomiting, confusion, blurriness, delayed in responses and drowsiness.
Compare and contrast the difference between a seizure and stroke.
Both are disorders of the brain. A stroke or cerebrovascular accident, occurs when blood supply is cut from the brain, leading to lack of oxygen. A seizure occurs when an electrical signal becomes out of control leading into more or less an electrical “brain storm”
Meningitis is the inflammation of the meninges as a result of infection leading to swelling. What is a danger of meningitis?
This can increase the pressure on the brain. This increase in pressure can exert enough force that can lead to brain injuries, necrosis or death.
In which layer of the meninges does CSF flow through?
CSF flows in between the two layers of dura mater.
What is unique about the dura mater in the brain, but not seen in the spinal cord?
The Dura mater has 2 layers in the brain, while the spinal cord has only one layer
From most exterior to interior, name the different meninges of the brain.
Dura mater => Arachnoid mater => Pia Mater
A patient is flown in from a severe car crash and upon closer examination, you discover necrosis (death of most or all of cells/tissue due to injury, dx or lack of blood supply) of the medulla oblongata. What are you expectations?
The individual is more likely than not, to die. Medulla oblongata is the house of many basic, but vital functions - heart and lung regulation, reticular formations in medulla oblongata has many ANS functions
What are the functions of the Metencephalon?
The metencephalon specializes into the pons and medulla oblongata.
Pons: links the inferior portions of the brain to the higher, medulla to the thalamus and cerebellum to other parts of the brain and spinal cord
Medulla Oblongata: Controls heart and lung functions as well as monitor the oxygen levels.
As you cross the road, you see some movements at the corner of your eye and reflexively turn your head in that direction. What neural tube structure is responsible for maintaining this motion?
The mesencephalon, it is responsible for the reflexive somatic motor responses generated in the region
On a hike in the mountains, you and Juan are walking a long a trail as the sun is setting. As you both hear a noise, both of you reflexively turn your heads towards the direction? Which neural tube structure is responsible for this action?
The mesencephalon, it is responsible for the reflexive somatic motor responses generated in the region
What functions are of the mesencephalon responsible for maintaining?
The mesencephalon or the midbrain is responsible for
- Processing visual/auditory data
- Reflexive somatic motor responses
- Maintains consciousness
The Diencephalon diverges interutero and produces what structures of the brain?
Di - Pair, therefore 2 thalami => Thalamus and hypothalamus + pineal gland
Through many studies over the year, scientists have discovered that many people taking a placebo melatonin are able to sleep. What does this confirm?
This confirms the hypothesis/idea that many normal people out there don’t need melatonin in order to sleep as their body may be creating sufficient amounts.`
Which structure of the neural tube is responsible for maintaining sleep through the expression of melatonin?
The Diencephalon’s Pineal gland regulates sleep through the neurotransmitter, melatonin.
The most posterior structure arising from the diencephalon is the….
A. Thalamus
B. Hypothalamus
C. Pineal Gland
D. Pons
C. Pineal Gland
What functions does the diencephalon and the mesencephalon share in common.
Both share the control of reflexive, subconscious skeletal muscle movement and role in consciousness through the Hypothalamus (diencephalon, altering state through circadian) and the midbrain (mesencephalon) maintaining it.
All of the following are functions of the hypothalamus except…
A. Maintenance of consciousness
B. Circadian Rhythm
C. Feeding and Thirst Centers
D. Communication with the pituitary gland
A. Maintenance of consciousness. All other functions are of the hypothalamus. Including subconscious skeletal muscle control
Explain the importance of CSF in the brain
The health of CSF directly impacts the health of the brain. CSF regulates gases, wastes and nutrients coming in and out as well as act as a protective mechanism in protecting the brain
True or False: Bundles of Axons are called tracts of nerves in the central nervous system
False. Bundles of axons are named differently based on the location. PNS - nerves and CNS - Tracts
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Upper motor neurons are exclusively considered in which peripheral nervous system?
The Somatic Nervous system. The ultimately control voluntary muscular movement.
As axons of the upper motor neurons run from the cerebral cortex down, they form tracts within the brain. What are the different tracts called? What are their beginning points and their final points?
Upper Motor Neuron Divisions of tracts are named based on their origin and destination.
- Corticospinal Tract - UMN from cerebral cortex -> LMN in spinal cord
- Corticobulbar Tract - UMN from Cerebral Cortex -> LMN in the brainstem
Nerves Branching from the brainstem are:
A. Cervical Nerves
B. Cranial Nerves
C. Spinal Nerves
D. Cerebral Nerves
B. Cranial Nerves. The brainstem is a portion of the brain (Remember cranial n. ≠ cervical n.)
True or False: Lower Motor Neurons in the spinal cord are as likely as lower motor neurons in the brainstem to innervate skeletal muscle of the head and neck.
False. Lower Motor Neurons in the spinal cord tend to innervate the trunk and limb muscles. Lower motor n. in the brainstem tend to innervate the head and neck
Somas of the Upper Motor Neurons are from
A. Cerebral cortex
B. Cerebellular Cortex
C. Ganglias
D. Tracts
A. Cerebral Cortex. Upper Motor n. send axons to the spinal cord or brainstem to synapse to lower motor neurons
Where in the CNS does Corticospinal tracts cross in order to reach their respective lower motor neuron?
Tracts cross over at the area in which the brainstem becomes the spinal cord.
Fact: Most axons of the corticospinal tract travel down (side of the brain then crossover to travel on to the other side of the body)
Regardless of dysfunction in the pathway, whether the upper motor n or the lower motor n. the ultimate phenotype shared by both is
A. Skeletal muscular weakness
B. Fasciculation
C. Clonus
D. Hyperreflexia
A. Skeletal Muscle Weakness
True or False: Dysfunction in the upper motor neuron can cause skeletal m. weakness (a shared phenotype with lower motor n dysfunction). However, UMN signs do not necessarily have to occur with weakness to be diagnosed with UMN
True. UMN signs can occur with or without weakness. They are sufficient enough for a diagnosis. This is not true of diagnosis with LMN dysfunction. In this disorder/syndrome, weakness must occur with lower motor signs.
Name the 4 signs of UMN signs
Hyperreflexia
Clonus
Hypertonia
Extensor Plantar response
The Mechanism of Hyperrefleixa due to UMN dysfunction is much unknown. What is one theory as to why this sign occurs? How does the role of UMN play a role?
It is assumed that without stimulus from the UMN, the LMN becomes hyper sensitive. W/NL stimulus, an overreaction will occur.
What is Clonus? How is this similar to fasciculation (seen LMN dysfunction) How are they different?
Clonus is the rhythmic contraction of the antagonist m. of our focus m.
Clonus is similar to fasciculation, as they are involuntary contractions, but differ on specific m.
Distinguish between dorsiflexions of the foot and plantar flexion.
These terms are used to describe the ankle’s movements.
Dorsiflexion is pulling the toes to the ankle, and plantar flexion is moving the toes away from the ankle
How are the different sets of movements:
A. Dorsiflexion & Plantar flexion
B. Extension & Flexion
Relate or differ to one another
A. These are the terms used to descrie the ankle’s movements when the angle of the shin and foot decrease - Dorsiflex and Increase in angle - plantar flex
(But! They are intertwined with B too. Plantar flexion - extension of the ankle and Dorsiflexion - flexion of the ankle)
You ask you patient to relax and then you grab their foot. In a swift motion, you move the limb away. Almost immediately, the limb starts to rhythmically move back and forth in an automatic manner. What is causing this action? What is the final diagnosis?
The antagonistic m. is causing the limb to contract back and forth rhythmically
Dx: Clonus
The UMN syndrome, Clonus, is characterized as the rhythmic contraction of an antagonistic m. when the m. of focus is rapidly stretched causing a repetitive contraction of both the m. of focus & antagonistic m. What is the likely reason why/mechanism of this diagnosis?
Hyperreflexia maybe the cause.
NL - pulling of 1 m causes its neighboring , to also be stretched.
ABNL - The small stretch in neighboring m. would result in m. reflex in which they quickly contract => our m of focus to stretch => reflex => stretch of neighboring m.
Differentiate bt hypertonia and hypotonia which Sx belongs to which syndrome?
Hypertonia - Increase in tone of a m. when atttempting to relax m. Causes most likely due to hyperreflexia. No really through of understanding why
Hypotonia - Decrease in Tone of m. When attempting to relax m. Cause most likely due to LMN injuries in which afferent or efferent n lacks communication
Describe how hyperreflexia of a muscle is a cause of hypertonia in this case. Is it similar to the mech seen in clonus
In attempting to relax the m, they move the supersensitive m. This causes the m. to automatically reflex => increase in tone and resistance
Clonus involves neighboring m. Hypertonia looks within the focus m. only
True or False: The abnormal, extensor plantar response, the UMN Sx is the plantar flexion of the ankle as the foot feels a scrape/pressure by the doctor.
False. This is the extension of the toes! Extension of the toes ≠ extension of the ankles
What is the normal reflex of your toes as you feel pressure under your foot?
NL - Flexion of the Toes (towards the foot, toes down)
ABNL - Babinski Sign (Fanning of Toes)
What mechanism induces the Babinski Sign?
Unknown Mechanism. Babinski Sign AKA Extensor Plantar Response (Toes Fanning)
Identify the sensory information that are precise touch sense.
Touch - Somatosensory Information
Information Type - Position, Vibration & Fine touch
Different types of somatosensory information tends to travel in different pathways. Of the two, what type of information travels in less precise tracts. What is the other pathway?
Less Precise - Pain, Temperature, Gross Touch
The other pathway of somatosensory is precise touch
True or False: Somatosensory information of the head including both precise and less precise somatosensory information travel in the spinal nerves to send signals about is surrounding area
False. Information of the head and neck tends to travel through cranial n.
Differentiate the difference between gross touch motor and gross touch in terms of sensation and perception
Gross motor - motion involving large skeletal m. due to contraction as a unit.
Gross Touch - more general afferent sensation
Compare and Contrast fine touch and gross touch. What are the alternative names for these senses?
Fine Touch - Discriminate touch. Detailed, localized information of touch
Gross Touch - Non-discriminate touch. Crude, overall general feeling or touch. No differentiation
Resting your hand on Juan’s stomach, it starts to growl from hunger. This vibration travels up your hand and… Describe its travel up the PNS and the CNS
Vibration along, with discriminatory touch, pressure, and proprioception travel the lemniscal pathway (precise pathway). The lemniscal tracts stay on the same side and cross in the medulla. To achieve contralateral perception (these information tend to be seen up higher on the spinal cord the other somatosensory info from spinothalamic pathway)
Information such as pain, temperature, & gross touch travel in
A. Spinothalamic pathway
B. Spinomedulla pathway
C. Lemniscal Pathway
D. Levinsky Pathway
A. Spinothalamic Pathway. After entering the spinal cord, it crosses over immediately in the spinal cord to achieve contralateral perception
Somatosensory Information such as pain enters the left side of the spinal cord. Illustrate this pathway for spinothalamic tracts
Information in the spinothalamic pathways cross over in the spinal cord and travels up the same side of the cerebral cortex
Somatosensroy information coming in from the head and neck travel to the cerebral cortex through cranial n. Differentiate the travel between the lemniscal and spinothalamic pathway
Spinothalamic tracts (Px, temp, and gross touch) travels down first before it ascends
Lemniscal Tracts (position, Vibration, and fine touch). There is no large dip in these seen in the spinothalamic tracts
Once information has been relayed to the thalamus, what occurs to the signal after?
Information then, is dispersed to their associated cortex or additional processings
In a traumatic car accident, you patient injures their right cerebral hemisphere. What do you expect their somatic sensation and perception will be?
The left side of his body and face will experience a lost of perception or abnormal perception. The right side of his body and face should still experience normal sensation and perception of somatosensory
Anatomically, where is the cerebellum? How can the cerebellum be further divided?
The cerebellum is inferior to the cerebrum and posterior to the pons and medulla. It can be further divided into the right and left cerebellular hemispheres
The function of the cerebellum
A. Initiates motor
B. Plan out motor and muscle movements
C. Coordinates motor independently
D. Corrects Movements
D. Cerebellum corrects motor to smooth out the motion and make the motion as intended. The cerebellum is unable to achieve this indpd and requires many other structures
You have to write an essay and plan to type it out. What structure in the brain allows this intention? What structure in the brain allows you to physically commit to it?
Primary motor cortex - allows planning a movement out
Cerebellum - allows motion to occur
True or False: Very little work has to be done from the cerebellum to revise a motion as the motion is planned by the cerebral cortex initially
False. Correction from the cerebellum occur frequently and almost all actions undergo revision
Once an UMN has synapsed onto a LMN and a motion is initiated, this movement is relayed back to the cerebellum for correction. How is this information relayed? How does the cerebellum process this incoming information?
he body’s motion is sensed and relayed by proprioceptors and therefore position of the body is sent to the cerebellum. There cerebellum weights the intended outcome from the primary cortex and actual motion. This is stimulated when there is a difference/conflict between the two.
True or False: Somatosensory information ascending to the cerebellum to give information about muscle movement, reaches consciousness
False. This information does not reach consciousness. It only goes to the cerebellum. but info from the cerebellum does ascend to the cerebral cortex after it sends to the thalamus first, but not always
How is the cerebellum able to compare the planned motion and the actual motion?
It receives axons from the upper motor n. from the primary motor cortex AND it receives axons from the proprioceptors from the m.
Explain the role of an UMN in relaying a message. Where are they located?
UMN are located in the CNS. These neurons send motor signal from the cerebral cortex to the spinal cord to the brain stem and play a role in controlling lower motor n. and their activities
Before an action can begin, the motor plan must be established. Meaning the primary motor cortex creates and plans the action. What aspects are created in this plan?
- Type of m. involved in motion
- Number of m. involved
- Intensity of contraction
- Duration of Contraction
Once the primary cortex has created a motor plan, where does it send its axons to? Describe the travel.
The UMN is sending axons through the cerebellum, past the brainstem and crosses over in the brainstem and differentiates as the corticospinal or corticobulbar tracts
Information from the proprioception delivering information about the position of muscles to the cerebellum.
A. Crosses over in the brainstem
B. Crosses over in the Spinal Cord
C. Crosses over in the thalamus
D. Stays on the same side to the cerebellum
D. Stays on the same side as it ascends to the cerebellum. It the crosses at the brainstem as the action travels from the cerebellum to the thalamus