Podcast
Questions and Answers
If a lesion selectively ablates the ventral posterolateral nucleus (VPL) of the thalamus, but spares the ventral posteromedial nucleus (VPM), which of the following sensory modalities would remain largely intact?
If a lesion selectively ablates the ventral posterolateral nucleus (VPL) of the thalamus, but spares the ventral posteromedial nucleus (VPM), which of the following sensory modalities would remain largely intact?
- Discriminative touch from the trunk.
- Fine touch and proprioception from the lower limbs.
- Vibration sense from the upper limbs.
- Pain and temperature sensation from the face. (correct)
In a patient presenting with pronounced ataxia, dysmetria, and intention tremor primarily affecting the upper limbs, magnetic resonance imaging reveals selective atrophy of a specific cerebellar region. Identify the MOST likely site of cerebellar damage.
In a patient presenting with pronounced ataxia, dysmetria, and intention tremor primarily affecting the upper limbs, magnetic resonance imaging reveals selective atrophy of a specific cerebellar region. Identify the MOST likely site of cerebellar damage.
- Flocculonodular lobe
- Posterior lobe lateral to the vermis (correct)
- Vermis
- Anterior lobe
A researcher is developing a novel therapeutic intervention targeting glutamate-mediated excitotoxicity following acute spinal cord injury. Which intervention would MOST effectively mitigate secondary damage by directly modulating astrocytic glutamate transporter function?
A researcher is developing a novel therapeutic intervention targeting glutamate-mediated excitotoxicity following acute spinal cord injury. Which intervention would MOST effectively mitigate secondary damage by directly modulating astrocytic glutamate transporter function?
- Administering a selective NR2B subunit antagonist to NMDA receptors.
- Enhancing neuronal uptake of cystine to promote glutathione synthesis.
- Upregulating expression of the glutamate transporter EAAT2/GLT-1 in astrocytes. (correct)
- Inhibiting microglial activation to prevent cytokine-mediated inflammation.
Following a traumatic brain injury, a patient exhibits a unique pattern of cognitive deficits, including severe impairment in generating verbs associated with visually presented nouns (e.g., failing to produce "kick" when shown a picture of a foot). Which specific brain region is MOST likely compromised?
Following a traumatic brain injury, a patient exhibits a unique pattern of cognitive deficits, including severe impairment in generating verbs associated with visually presented nouns (e.g., failing to produce "kick" when shown a picture of a foot). Which specific brain region is MOST likely compromised?
A neuroanatomical study involving tract-tracing techniques in primates reveals a previously uncharacterized pathway projecting from the amygdala directly to layer IV of the primary visual cortex. What is the MOST plausible functional implication of this novel pathway?
A neuroanatomical study involving tract-tracing techniques in primates reveals a previously uncharacterized pathway projecting from the amygdala directly to layer IV of the primary visual cortex. What is the MOST plausible functional implication of this novel pathway?
A patient presents with a constellation of symptoms including anosmia, hypogonadism, and midline facial defects. Genetic analysis reveals a loss-of-function mutation in a gene critical for the migration of GnRH-secreting neurons during development. Which embryonic brain region was MOST likely disrupted, leading to this clinical presentation?
A patient presents with a constellation of symptoms including anosmia, hypogonadism, and midline facial defects. Genetic analysis reveals a loss-of-function mutation in a gene critical for the migration of GnRH-secreting neurons during development. Which embryonic brain region was MOST likely disrupted, leading to this clinical presentation?
In the context of spinal cord injury research, a novel therapeutic strategy aims to promote axonal regeneration across the lesion site by manipulating the extracellular matrix. Which specific intervention would MOST effectively counteract the inhibitory effects of chondroitin sulfate proteoglycans (CSPGs), a major component of glial scars?
In the context of spinal cord injury research, a novel therapeutic strategy aims to promote axonal regeneration across the lesion site by manipulating the extracellular matrix. Which specific intervention would MOST effectively counteract the inhibitory effects of chondroitin sulfate proteoglycans (CSPGs), a major component of glial scars?
A patient exhibits a pronounced deficit in comprehending prosody (emotional tone) in speech, while their ability to understand the literal meaning of words remains intact. Lesion analysis would MOST likely reveal damage to which specific brain region?
A patient exhibits a pronounced deficit in comprehending prosody (emotional tone) in speech, while their ability to understand the literal meaning of words remains intact. Lesion analysis would MOST likely reveal damage to which specific brain region?
Consider a scenario where a novel synthetic drug selectively enhances the activity of the pontine respiratory group (PRG) in the pons. What would be the MOST likely physiological consequence observed in an individual administered with this drug?
Consider a scenario where a novel synthetic drug selectively enhances the activity of the pontine respiratory group (PRG) in the pons. What would be the MOST likely physiological consequence observed in an individual administered with this drug?
A neuroimaging study uses diffusion tensor imaging (DTI) to assess white matter integrity in individuals with chronic traumatic encephalopathy (CTE). Which specific DTI metric would MOST sensitively detect early axonal damage and demyelination in the corpus callosum?
A neuroimaging study uses diffusion tensor imaging (DTI) to assess white matter integrity in individuals with chronic traumatic encephalopathy (CTE). Which specific DTI metric would MOST sensitively detect early axonal damage and demyelination in the corpus callosum?
During human brain development, a mutation affects the normal function of radial glial cells. What is the MOST likely consequence of this mutation on cortical organization?
During human brain development, a mutation affects the normal function of radial glial cells. What is the MOST likely consequence of this mutation on cortical organization?
A researcher is investigating the role of specific transcription factors in the differentiation of gustatory receptor cells. Which transcription factor is MOST critically involved in specifying the identity of type II taste receptor cells, responsible for detecting sweet, bitter, and umami tastes?
A researcher is investigating the role of specific transcription factors in the differentiation of gustatory receptor cells. Which transcription factor is MOST critically involved in specifying the identity of type II taste receptor cells, responsible for detecting sweet, bitter, and umami tastes?
A patient presents with selective damage to the arcuate fasciculus. Which of the following symptoms would MOST likely be observed?
A patient presents with selective damage to the arcuate fasciculus. Which of the following symptoms would MOST likely be observed?
A researcher discovers a novel class of interneurons within the spinal cord dorsal horn that selectively inhibit the activity of projection neurons expressing the neurokinin 1 receptor (NK1R). What is the MOST likely functional role of these interneurons?
A researcher discovers a novel class of interneurons within the spinal cord dorsal horn that selectively inhibit the activity of projection neurons expressing the neurokinin 1 receptor (NK1R). What is the MOST likely functional role of these interneurons?
A patient who has had a stroke now experiences a profound sensory loss that is disproportionately affecting their ability to discriminate fine textures and shapes by touch. This condition is known as tactile agnosia. Where is the MOST probable location of the lesion causing this deficit?
A patient who has had a stroke now experiences a profound sensory loss that is disproportionately affecting their ability to discriminate fine textures and shapes by touch. This condition is known as tactile agnosia. Where is the MOST probable location of the lesion causing this deficit?
A study using optogenetics selectively activates astrocytes in the hypothalamus of mice. The researchers observe a significant decrease in food intake and an increase in energy expenditure. Which specific hypothalamic region is MOST likely being targeted by this optogenetic manipulation?
A study using optogenetics selectively activates astrocytes in the hypothalamus of mice. The researchers observe a significant decrease in food intake and an increase in energy expenditure. Which specific hypothalamic region is MOST likely being targeted by this optogenetic manipulation?
Following a viral infection, a patient develops selective damage to neurons within the dorsal root ganglia (DRG) that express the TRPV1 receptor. What sensory modality would be MOST affected by this neuronal loss?
Following a viral infection, a patient develops selective damage to neurons within the dorsal root ganglia (DRG) that express the TRPV1 receptor. What sensory modality would be MOST affected by this neuronal loss?
A neuroscientist is investigating the role of the cerebellum in motor adaptation using a prism adaptation task. Which specific cerebellar circuit is MOST critically involved in recalibrating motor commands to compensate for the visual distortion induced by the prisms?
A neuroscientist is investigating the role of the cerebellum in motor adaptation using a prism adaptation task. Which specific cerebellar circuit is MOST critically involved in recalibrating motor commands to compensate for the visual distortion induced by the prisms?
A researcher is studying the effects of a novel neurotoxin that selectively disrupts the function of ependymal cells lining the cerebral ventricles. What would be the MOST immediate consequence of this disruption on the central nervous system?
A researcher is studying the effects of a novel neurotoxin that selectively disrupts the function of ependymal cells lining the cerebral ventricles. What would be the MOST immediate consequence of this disruption on the central nervous system?
Following a spinal cord injury, a patient experiences exaggerated muscle tone and hyperactive reflexes below the level of the lesion. This condition, known as spasticity. What is the MOST likely underlying mechanism contributing to this spasticity?
Following a spinal cord injury, a patient experiences exaggerated muscle tone and hyperactive reflexes below the level of the lesion. This condition, known as spasticity. What is the MOST likely underlying mechanism contributing to this spasticity?
In an experiment involving targeted gene knockout in mice, the gene encoding aquaporin-4 (AQP4) is selectively deleted in astrocytes surrounding cerebral blood vessels. What would be the MOST likely consequence of this deletion on brain function following a stroke?
In an experiment involving targeted gene knockout in mice, the gene encoding aquaporin-4 (AQP4) is selectively deleted in astrocytes surrounding cerebral blood vessels. What would be the MOST likely consequence of this deletion on brain function following a stroke?
A patient presents with significant behavioral changes, including impaired social judgment, disinhibition, and a marked inability to plan and execute complex tasks. Neuroimaging reveals selective atrophy of which specific region?
A patient presents with significant behavioral changes, including impaired social judgment, disinhibition, and a marked inability to plan and execute complex tasks. Neuroimaging reveals selective atrophy of which specific region?
A researcher is investigating the mechanisms underlying the development of phantom limb pain following amputation. Which specific neuroplastic change in the somatosensory cortex is MOST likely contributing to the perception of pain in the missing limb?
A researcher is investigating the mechanisms underlying the development of phantom limb pain following amputation. Which specific neuroplastic change in the somatosensory cortex is MOST likely contributing to the perception of pain in the missing limb?
A patient presents with hypotonia, ataxia, and intention tremor. Imaging reveals damage restricted to the cerebellum. Which specific region of the cerebellum is MOST likely affected?
A patient presents with hypotonia, ataxia, and intention tremor. Imaging reveals damage restricted to the cerebellum. Which specific region of the cerebellum is MOST likely affected?
A researcher aims to develop a targeted therapy to enhance axonal regeneration following spinal cord injury by manipulating intrinsic neuronal properties. Which intracellular signaling pathway would be MOST effective in promoting axon growth by overcoming the inhibitory effects of myelin-associated inhibitors?
A researcher aims to develop a targeted therapy to enhance axonal regeneration following spinal cord injury by manipulating intrinsic neuronal properties. Which intracellular signaling pathway would be MOST effective in promoting axon growth by overcoming the inhibitory effects of myelin-associated inhibitors?
Following a stroke, a patient exhibits hemispatial neglect, characterized by a profound lack of awareness of stimuli presented to one side of their body/surroundings, despite intact sensory function. Where is the stroke MOST likely located?
Following a stroke, a patient exhibits hemispatial neglect, characterized by a profound lack of awareness of stimuli presented to one side of their body/surroundings, despite intact sensory function. Where is the stroke MOST likely located?
In a study examining the effects of specific neurotransmitters on sensory perception, a researcher selectively blocks the release of substance P in the dorsal horn of the spinal cord. What would be the MOST likely consequence on the perception of pain?
In a study examining the effects of specific neurotransmitters on sensory perception, a researcher selectively blocks the release of substance P in the dorsal horn of the spinal cord. What would be the MOST likely consequence on the perception of pain?
Researchers are investigating potential therapeutic targets for promoting remyelination in multiple sclerosis (MS). Which specific cell type would be MOST effectively targeted to enhance myelin regeneration in demyelinated axons?
Researchers are investigating potential therapeutic targets for promoting remyelination in multiple sclerosis (MS). Which specific cell type would be MOST effectively targeted to enhance myelin regeneration in demyelinated axons?
A patient presents with a lesion affecting the anterior portion of the spinal cord. Which sensory modalities would be MOST affected?
A patient presents with a lesion affecting the anterior portion of the spinal cord. Which sensory modalities would be MOST affected?
A researcher is studying the molecular mechanisms underlying the formation of the blood-brain barrier (BBB). Which specific protein is MOST critical for the formation of tight junctions between endothelial cells in brain capillaries, thereby restricting paracellular permeability?
A researcher is studying the molecular mechanisms underlying the formation of the blood-brain barrier (BBB). Which specific protein is MOST critical for the formation of tight junctions between endothelial cells in brain capillaries, thereby restricting paracellular permeability?
Following damage to the vestibulocerebellum, also known as the flocculonodular lobe, what specific function is MOST likely to be impaired?
Following damage to the vestibulocerebellum, also known as the flocculonodular lobe, what specific function is MOST likely to be impaired?
A researcher is investigating the role of specific cranial nerves in taste perception. Selective transection of which nerve would MOST significantly impair the ability to taste sweet, sour, and salty substances on the anterior two-thirds of the tongue?
A researcher is investigating the role of specific cranial nerves in taste perception. Selective transection of which nerve would MOST significantly impair the ability to taste sweet, sour, and salty substances on the anterior two-thirds of the tongue?
A study found that patients with damage to a certain area of the spinal cord could still feel a crude sense of touch, but could not identify exactly where they were being touched. Where is the MOST probable location of damage?
A study found that patients with damage to a certain area of the spinal cord could still feel a crude sense of touch, but could not identify exactly where they were being touched. Where is the MOST probable location of damage?
In an experiment investigating the role of microglia in synaptic pruning during brain development, researchers selectively deplete microglia from the developing mouse cortex. Which of the following outcomes would be MOST likely?
In an experiment investigating the role of microglia in synaptic pruning during brain development, researchers selectively deplete microglia from the developing mouse cortex. Which of the following outcomes would be MOST likely?
A patient presents with a profound loss of smell, and an MRI reveals selective atrophy of the olfactory bulb. Which cranial nerve is MOST directly affected?
A patient presents with a profound loss of smell, and an MRI reveals selective atrophy of the olfactory bulb. Which cranial nerve is MOST directly affected?
A researcher is investigating the role of the corpus callosum in interhemispheric communication. In an experimental paradigm involving bimanual motor coordination, which specific behavioral outcome would be MOST sensitive to disruption of callosal function?
A researcher is investigating the role of the corpus callosum in interhemispheric communication. In an experimental paradigm involving bimanual motor coordination, which specific behavioral outcome would be MOST sensitive to disruption of callosal function?
A patient has a lesion in the medulla oblongata. Which of the following is MOST likely to occur?
A patient has a lesion in the medulla oblongata. Which of the following is MOST likely to occur?
Flashcards
Embryonic brain regions
Embryonic brain regions
Forebrain, midbrain, hindbrain are the scientific names.
What are the two parts of the forebrain?
What are the two parts of the forebrain?
Telencephalon and diencephalon.
Cerebrum and Diencephalon.
Cerebrum and Diencephalon.
The cerebrum controls higher functions, the diencephalon relays sensory information.
Midbrain scientific name
Midbrain scientific name
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Hindbrain regions
Hindbrain regions
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What does the metencephalon comprise?
What does the metencephalon comprise?
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Myelencephalon
Myelencephalon
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Primary brain vesicles
Primary brain vesicles
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Secondary brain vesicles
Secondary brain vesicles
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Gray vs. white matter
Gray vs. white matter
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List the brain's meninges
List the brain's meninges
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Spaces between meninges
Spaces between meninges
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Brain ventricles
Brain ventricles
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Functions of cerebrospinal fluid
Functions of cerebrospinal fluid
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Blood-brain barrier components
Blood-brain barrier components
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Blood-brain barrier function
Blood-brain barrier function
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Cerebral hemispheres
Cerebral hemispheres
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Corpus callosum
Corpus callosum
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Cerebral lobes
Cerebral lobes
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Motor cortical regions
Motor cortical regions
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Sensory cortical regions
Sensory cortical regions
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Prefrontal cortex functions
Prefrontal cortex functions
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Wernicke's area and Gnostic area
Wernicke's area and Gnostic area
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Cerebral lateralization
Cerebral lateralization
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Hypothalamus functions
Hypothalamus functions
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Cerebellum
Cerebellum
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Major features of the midbrain
Major features of the midbrain
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Respiratory center
Respiratory center
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Medulla oblongata autonomic centers
Medulla oblongata autonomic centers
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12 cranial nerves
12 cranial nerves
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Cranial Nerve functions
Cranial Nerve functions
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Spinal cord functions
Spinal cord functions
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Anatomic subdivisions of the spinal cord
Anatomic subdivisions of the spinal cord
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Spinal nerves
Spinal nerves
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Cauda equina formation
Cauda equina formation
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Spinal cord and vertebral column
Spinal cord and vertebral column
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Spinal cord meninges
Spinal cord meninges
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Gray matter locations
Gray matter locations
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Sensory and motor input to the spinal cord
Sensory and motor input to the spinal cord
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White matter location
White matter location
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Study Notes
General Regions of the Brain
- Forebrain: responsible for higher-level cognitive functions
- Midbrain: involved in motor control, vision, and hearing
- Hindbrain: regulates autonomic functions and movement
Embryonic Brain Regions
- Prosencephalon (forebrain): telencephalon (cerebrum) and diencephalon (thalamus, hypothalamus, epithalamus)
- Mesencephalon (midbrain): midbrain
- Rhombencephalon (hindbrain): metencephalon (pons and cerebellum) and myelencephalon (medulla oblongata)
Secondary Brain Vesicles
- Telencephalon: forms the cerebrum
- Diencephalon: forms the thalamus, hypothalamus, and epithalamus
- Mesencephalon: forms the midbrain
- Metencephalon: forms the pons and cerebellum
- Myelencephalon: forms the medulla oblongata
Gray and White Matter
- Gray matter: contains neuron cell bodies, dendrites, and unmyelinated axons and is located in the cortex and nuclei
- White matter: contains myelinated axons and is located in the deeper layers of the brain
- Gray matter processes information, while white matter transmits signals
Meninges
- Dura mater: tough, outermost layer
- Arachnoid mater: middle layer with a spiderweb-like appearance
- Pia mater: delicate, innermost layer
- Subdural space: located between the dura mater and arachnoid mater
- Subarachnoid space: located between the arachnoid mater and pia mater and contains cerebrospinal fluid
Brain Ventricles
- Lateral ventricles: located in each cerebral hemisphere
- Third ventricle: located in the diencephalon
- Fourth ventricle: located between the pons and cerebellum
- Ventricles are filled with cerebrospinal fluid and lined by ependymal cells
Cerebrospinal Fluid (CSF)
- Cushions and protects the brain and spinal cord
- Transports nutrients and removes waste products
- Helps regulate the chemical environment of the brain
Blood-Brain Barrier (BBB)
- Formed by tight junctions between endothelial cells of brain capillaries, supported by astrocytes
- Protects the brain from harmful substances
How the BBB Protects the Brain
- Restricts the passage of many substances from the bloodstream into the brain
- Allows the passage of essential nutrients via selective transport mechanisms
Cerebral Hemispheres
- Left hemisphere: controls the right side of the body and involved in language, math, and logic
- Right hemisphere: controls the left side of the body and involved in spatial awareness, creativity, and facial recognition
Corpus Callosum
- Connects the left and right cerebral hemispheres
- Facilitates communication between the two hemispheres
Cerebral Lobes
- Frontal lobe: involved in motor control, planning, decision-making, and personality
- Parietal lobe: processes sensory information
- Temporal lobe: involved in auditory processing, memory, and language
- Occipital lobe: processes visual information
- Insula: involved in taste, visceral sensations, and empathy
Motor Cortical Regions
- Primary motor cortex: controls voluntary movements
- Premotor cortex: plans and coordinates complex movements
- Motor association areas: integrate sensory information with motor commands
Sensory Cortical Regions
- Primary somatosensory cortex: receives sensory information from the body
- Somatosensory association area: interprets sensory information
- Visual cortex: receives visual information
- Auditory cortex: receives auditory information
Prefrontal Cortex
- Involved in executive functions such as planning, decision-making, and working memory
- Functions differently in adults and teenagers due to ongoing brain development
Wernicke Area and Gnostic Area
- Wernicke area: involved in language comprehension
- Gnostic area: integrates sensory information to create a complete perception of the world
Cerebral Lateralization
- The specialization of functions between the left and right cerebral hemispheres
Left and Right Hemisphere Functions
- Left hemisphere: language, math, logic
- Right hemisphere: spatial awareness, creativity, facial recognition
Hypothalamus
- Controls the autonomic nervous system
- Regulates body temperature
- Regulates hunger and thirst
- Regulates sleep-wake cycles
- Controls the endocrine system
- Involved in emotional responses
- Regulates sexual behavior
Midbrain
- Contains the superior and inferior colliculi, substantia nigra, and red nucleus
- Involved in motor control, vision, and hearing
Respiratory Center in the Pons
- Pneumotaxic center: regulates the rate and depth of breathing
- Apneustic center: stimulates inspiration
Medulla Oblongata
- Contains the cardiac, vasomotor, and respiratory centers
- Controls autonomic functions such as heart rate, blood pressure, and breathing
Autonomic Centers of the Medulla
- Cardiac center: regulates heart rate and force of contraction
- Vasomotor center: regulates blood vessel diameter and blood pressure
- Respiratory center: regulates breathing rate and depth
Cerebellum
- Coordinates voluntary movements
- Maintains balance and posture
- Involved in motor learning
Cranial Nerves
- Olfactory (I): smell
- Optic (II): vision
- Oculomotor (III): eye movement
- Trochlear (IV): eye movement
- Trigeminal (V): facial sensation and chewing
- Abducens (VI): eye movement
- Facial (VII): facial expression and taste
- Vestibulocochlear (VIII): hearing and balance
- Glossopharyngeal (IX): taste and swallowing
- Vagus (X): autonomic functions
- Accessory (XI): head and shoulder movement
- Hypoglossal (XII): tongue movement
Functions of Cranial Nerves
- Cranial nerves perform specialized sensory or motor functions
- Some cranial nerves carry both sensory and motor information
Spinal Cord and Spinal Nerves
- Spinal cord: conducts sensory information from the body to the brain and motor information from the brain to the body
- Spinal nerves: transmit sensory and motor information between the spinal cord and the body
Spinal Cord Structure
- Cervical, thoracic, lumbar, sacral, and coccygeal regions
- Anterior median fissure and posterior median sulcus
- Gray matter and white matter
Spinal Nerves
- 31 pairs of spinal nerves: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal
- Each spinal nerve is formed by the union of a dorsal root and a ventral root
Cauda Equina
- Formed by the lumbar and sacral spinal nerve roots
- Arises during development due to differential growth rates of the spinal cord and vertebral column
Spinal Cord and Vertebral Column
- Spinal cord is shorter than the vertebral column
- Spinal nerves exit the vertebral column through intervertebral foramina
Spinal Cord Meninges
- Dura mater, arachnoid mater, and pia mater
- Epidural space, subdural space, and subarachnoid space
- Meninges protect the spinal cord and provide support
Gray Matter of the Spinal Cord
- Anterior (ventral) horn: contains motor neurons
- Posterior (dorsal) horn: contains sensory neurons
- Lateral horn: contains sympathetic neurons
Gray Matter Regions
- Anterior horn: contains motor neurons that innervate skeletal muscles
- Posterior horn: receives sensory information from the body
- Lateral horn: contains sympathetic neurons that innervate visceral organs
Sensory and Motor Input to the Spinal Cord
- Sensory input enters the spinal cord via the dorsal root
- Motor output exits the spinal cord via the ventral root
White Matter of the Spinal Cord
- Anterior, lateral, and posterior columns
- Contains ascending and descending tracts
Dermatome
- An area of skin innervated by a single spinal nerve
- Clinically significant for identifying the location of spinal nerve damage
Properties of a Reflex
- Rapid, involuntary, and predictable response to a stimulus
Reflex Classification
- Reflexes can be classified by development, response, complexity, and processing site
Reflex Arc
- Sensory receptor, sensory neuron, integration center, motor neuron, and effector
Ways to Classify a Reflex
- Spinal or cranial
- Somatic or visceral
- Monosynaptic or polysynaptic
- Ipsilateral or contralateral
- Innate or acquired
Common Spinal Reflexes
- Stretch reflex: maintains muscle tone and posture
- Golgi tendon reflex: prevents muscle damage
- Withdrawal reflex: moves a body part away from a painful stimulus
- Crossed-extensor reflex: maintains balance during the withdrawal reflex
Hypoactive and Hyperactive Reflexes
- Hypoactive reflexes: indicate damage to the lower motor neurons or muscle
- Hyperactive reflexes: indicate damage to the upper motor neurons
Sensory Receptors as Transducers
- Sensory receptors convert different forms of energy into electrical signals
Sensory Receptor Structure
- Sensory receptors have a receptive field, which is the area within which they can detect stimuli
- The size of the receptive field affects the precision of stimulus localization
Sensation
- Conscious awareness of a stimulus
Stimulus Characteristics
- Modality (type of stimulus)
- Location (where the stimulus is applied)
- Intensity (strength of the stimulus)
- Duration (how long the stimulus lasts)
Receptor Classification Criteria
- Type of stimulus
- Location
- Structure
Types of Sensory Receptors
- Mechanoreceptors: respond to mechanical forces
- Thermoreceptors: respond to temperature changes
- Photoreceptors: respond to light
- Chemoreceptors: respond to chemicals
- Nociceptors: respond to pain
Tactile Receptors
- Unencapsulated tactile receptors: free nerve endings, tactile discs, and root hair plexuses
- Encapsulated tactile receptors: tactile corpuscles, lamellated corpuscles, and bulbous corpuscles
Referred Pain
- Pain perceived at a location other than the site of the painful stimulus
- Occurs because visceral and somatic sensory neurons converge on the same ascending pathways
Olfactory Receptors
- Located in the olfactory epithelium in the nasal cavity
- Olfactory receptors bind odorants, leading to the generation of action potentials
Papillae of the Tongue
- Filiform papillae: provide texture but do not contain taste buds
- Fungiform papillae: contain taste buds and are located on the tip and sides of the tongue
- Circumvallate papillae: contain taste buds and are located on the back of the tongue
- Foliate papillae: contain taste buds and are located on the sides of the tongue
Gustatory Receptors
- Located in taste buds on the tongue, palate, and pharynx
- Gustatory receptors detect different tastes such as sweet, sour, salty, bitter, and umami
Types of Tastes
- Sweet, sour, salty, bitter, and umami
- Smell enhances the perception of taste
Accessory Structures of the Eye
- Eyelids, eyelashes, eyebrows, lacrimal apparatus, and extrinsic eye muscles
- Protect the eye and aid in vision
Structures of the Eye
- Fibrous tunic: sclera and cornea
- Vascular tunic: choroid, ciliary body, and iris
- Retina: contains photoreceptors
Structures of the Ear
- Outer ear: auricle and external acoustic meatus
- Middle ear: tympanic membrane and auditory ossicles
- Inner ear: bony labyrinth and membranous labyrinth
Auditory Ossicles
- Malleus, incus, and stapes
- Transmit vibrations from the tympanic membrane to the inner ear
Bony and Membranous Labyrinth
- Bony labyrinth: a series of bony cavities in the temporal bone
- Membranous labyrinth: a series of membranous sacs and ducts within the bony labyrinth
Cochlea
- Contains the spiral organ (organ of Corti), which contains hair cells that detect sound vibrations
- Vibrations of the stapes on the oval window cause pressure waves in the perilymph of the cochlea
Frequency and Intensity of Sound
- Frequency: the number of sound waves per second, measured in Hertz (Hz)
- Intensity: the amplitude of sound waves, measured in decibels (dB)
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