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Which functional area of the cerebral cortex is primarily responsible for controlling voluntary movements?
What percentage of the brain's mass is accounted for by the cortex?
Which area of the cortex is involved in the planning of movements?
Which hemisphere of the brain typically contains Broca's area?
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What is the primary function of the primary motor cortex?
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How do the two hemispheres of the brain generally function in relation to the body?
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What role does the frontal eye field play in the cerebral cortex?
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Which type of area in the cortex integrates diverse information?
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What type of skills does the premotor cortex coordinate?
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Which type of area allows for conscious awareness of sensations?
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What does the Central Nervous System (CNS) primarily consist of?
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What is the process of cephalization primarily associated with?
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Which of the following structures is NOT part of the surface anatomy of the brain?
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During which stage of embryonic development does the neural plate form?
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What structure develops from the fusion of the neural groove?
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What is a characteristic of the human brain compared to other species?
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Which part of the CNS is responsible for coordination and balance?
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What is the primary role of the ectoderm during the early stages of nervous system development?
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At what embryonic day does the neural groove begin to form?
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The brain is composed of what type of tissue?
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What is primarily found at the core of the spinal cord?
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Which ventricular component is NOT part of the brain's ventricular system?
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Which of the following accurately describes the composition of the cerebral hemispheres?
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What is the primary function of the deep sulci in the cerebral hemisphere?
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Which lobe of the cerebral hemisphere is separated from the parietal lobe by the central sulcus?
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How much of the total mass of the brain is made up by the cerebral hemispheres?
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What separates the parietal and occipital lobes of the cerebral hemispheres?
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Which statement about the cerebrum is true?
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Which structure is NOT part of the brain's ventricular system?
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What type of matter surrounds the central cavity of the spinal cord?
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What sensory modalities does the primary somatosensory cortex primarily process?
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What is the main function of the somatosensory association cortex?
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Where is the primary visual cortex located in the brain?
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Which area is responsible for the perception of sounds such as pitch and rhythm?
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What type of information does the visual association area interpret?
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Which of the following is NOT a function of the primary somatosensory cortex?
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What does the auditory association area primarily store?
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Which area is associated with higher cognitive functions, such as decision making and social behavior?
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What key role does the general interpretation area serve in the brain?
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What distinguishes the auditory association area from the primary auditory cortex?
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What function does cerebrospinal fluid (CSF) NOT perform?
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Which of the following best describes the role of the choroid plexuses?
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How does the blood-brain barrier maintain the brain's environment?
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What is the primary function of the meninges?
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Which layer of the meninges is the deepest and clings tightly to the brain?
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What mechanism allows the spinal cord's communication with the brain?
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What does cerebrospinal fluid primarily resemble?
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Which structure provides support and anchorage to the spinal cord?
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What is the primary role of the epidural space in relation to the spinal cord?
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How do the two layers of the dura mater function?
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Which structure allows for the absorption of cerebrospinal fluid into the venous blood?
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What occurs when stress affects the blood-brain barrier?
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What is a characteristic feature of the cervical and lumbar enlargements of the spinal cord?
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What is the role of the blood-brain barrier?
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What is one characteristic of the composition of cerebrospinal fluid compared to blood plasma?
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Which of the following is NOT a function of the meninges?
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Study Notes
The Central Nervous System
- The CNS is comprised of the brain and spinal cord.
- Cephalization is the elaboration of the anterior portion of the CNS, resulting in an increase in neurons in the head.
- The human brain is the most complex example of cephalization.
Embryonic Development
- The neural plate is formed from the thickening of the ectoderm along the dorsal midline during the first 26 days of development.
- The neural plate invaginates to form a groove flanked by neural folds.
- The neural groove fuses dorsally to form the neural tube.
Basic Pattern of the Central Nervous System
- The spinal cord's central cavity is surrounded by gray matter, with white matter composed of myelinated fiber tracts located externally.
- The brain is similar to the spinal cord but has additional gray matter.
- The cerebellum has gray matter in nuclei, while the cerebrum also has nuclei and additional gray matter in the cortex.
Ventricles of the Brain
- Ventricles are expansions of the lumen of the neural tube.
- The ventricles include:
- The paired C-shaped lateral ventricles
- The third ventricle
- The fourth ventricle
Cerebral Hemispheres
- They constitute the superior part of the brain and comprise 83% of its mass.
- Cerebral hemispheres have ridges called gyri and shallow grooves called sulci.
- Deep grooves in cerebral hemispheres are called fissures.
Major Lobes, Gyri, and Sulci of the Cerebral Hemisphere
- Deep sulci divide the cerebral hemispheres into four major lobes:
- Frontal
- Parietal
- Temporal
- Occipital
Major Lobes, Gyri, and Sulci of the Cerebral Hemisphere (continued)
- The central sulcus separates the frontal and parietal lobes.
- The parieto-occipital sulcus separates the parietal and occipital lobes.
- The lateral sulcus separates the parietal and temporal lobes.
- The precentral and postcentral gyri border the central sulcus.
Cerebral Cortex
- The cerebral cortex, the superficial gray matter, accounts for 40% of the brain's mass.
- It enables sensation, communication, memory, understanding, and voluntary movements.
- Each hemisphere operates contralaterally, controlling the opposite side of the body.
Functional Areas of the Cerebral Cortex
- The three types of functional areas:
- Motor areas: control voluntary movement
- Sensory areas: provide conscious awareness of sensation
- Association areas: integrate diverse information
Cerebral Cortex: Motor Areas
- Motor areas comprise:
- Primary (somatic) motor cortex
- Premotor cortex
- Broca's area
- Frontal eye field
Primary Motor Cortex
- This area is located in the precentral gyrus.
- It contains pyramidal cells with axons that compose the corticospinal tracts.
- Allows conscious control of precise, skilled, and voluntary movements.
Premotor Cortex
- This area sits anterior to the precentral gyrus.
- Controls learned, repetitious, or patterned motor skills.
- Coordinates simultaneous or sequential actions.
- Involved in planning movements.
Broca's Area
- Located anterior to the inferior region of the premotor area.
- Usually present in the left hemisphere.
- Functions as a motor speech area directing tongue muscles.
- Becomes active when preparing to speak.
Frontal Eye Field
- Located anterior to the premotor cortex and superior to Broca's area.
- Controls voluntary eye movement.
Sensory Areas
- Sensory areas include:
- Primary somatosensory cortex
- Somatosensory association cortex
- Visual and auditory areas
- Olfactory, gustatory, and vestibular cortices.
Primary Somatosensory Cortex
- Located in the postcentral gyrus, this area:
- Receives information from the skin and skeletal muscles.
- Exhibits spatial discrimination.
Somatosensory Association Cortex
- Located posterior to the primary somatosensory cortex.
- Integrates sensory information.
- Forms a comprehensive understanding of the stimulus.
- Determines size, texture, and relationship of parts of the stimulus.
Visual Areas
-
The primary visual cortex:
- Located at the extreme posterior tip of the occipital lobe.
- Receives visual information from the retinas.
-
The visual association area:
- Surrounds the primary visual cortex.
- Interprets visual stimuli, including color, form, and movement.
Auditory Areas
-
The primary auditory cortex:
- Located at the superior margin of the temporal lobe.
- Receives information related to pitch, rhythm, and loudness.
-
The auditory association area:
- Located posterior to the primary auditory cortex.
- Stores memories of sounds and permits perception of sounds.
- Contains Wernicke's area.
Association Areas
- Association areas comprise:
- Prefrontal cortex
- Language areas
- General (common) interpretation area
- Visceral association area
Prefrontal Cortex
- Located in the frontal lobe.
- Involved in intellect, complex learning abilities, personality, and judgment.
- Responsible for working memory, abstract ideas, judgment, reasoning, and planning.
- The most complex part of the cerebral cortex.
Language Areas
- Language areas involve:
- Wernicke's area: responsible for speech understanding and sounds.
- Broca's area: responsible for speech production.
- Lateral sulcus: separates the frontal and temporal lobes.
General Interpretation Area
- Receives information from all association areas.
- Permits us to give meaning to information we receive.
- Makes us aware of the objects around us.
Visceral Association Area
- Located in the insular cortex, deep within the lateral sulcus.
- Controls visceral functions like hunger, thirst, emotions, and autonomic nervous system regulation.
Cerebellum
- Located behind the brain stem and below the cerebrum.
- Controls equilibrium, posture, and fine motor coordination.
- Aids in motor learning and planning.
- Receives a copy of motor plans from the cerebrum.
Brain Stem
- Contains:
- Midbrain
- Pons
- Medulla oblongata
- Controls vital functions like respiration, heart rate, and blood pressure.
- Responsible for reflexes.
Diencephalon
- Located in the central core of the brain.
- Contains:
- Thalamus: the relay center for sensory information.
- Hypothalamus: controls homeostatic functions like hunger, thirst, temperature regulation, and sleep.
- Contains the epithalamus, which includes the pineal gland for hormone secretion.
Cranial Nerves
- 12 pairs of cranial nerves.
- Mostly serve the head and neck regions.
- Connect directly to the brain.
Spinal Cord
- A column of nervous tissue that extends from the medulla oblongata.
- Enclosed by vertebral column.
- Transmits impulses to and from the brain.
- Contains 31 pairs of spinal nerves.
Spinal Nerves
- Serve the body periphery.
- Formed from the fusion of dorsal and ventral roots.
- Each nerve connects to the spinal cord by a pair of roots:
- Dorsal root: carries sensory information, which serves as an afferent pathway.
- Ventral root: carries motor information, which serves as an efferent pathway.
Peripheral Nervous System (PNS)
- PNS includes all nervous tissue outside of the CNS.
- Composed of:
- Cranial nerves
- Spinal nerves
- Ganglia: collections of neuron cell bodies outside the CNS.
Brain Protection
- Brain is protected by bone, meninges, and cerebrospinal fluid (CSF)
- Blood-brain barrier shields the brain from harmful substances
Meninges
- Three membranes external to the CNS: dura mater, arachnoid mater, and pia mater
- Functions:
- Cover and protect the CNS
- Protect blood vessels and enclose venous sinuses
- Contain CSF
- Form partitions within the skull
Dura Mater
- Leathery and strong
- Composed of two fibrous connective tissue layers
- Layers separate in some areas to form dural sinuses
Arachnoid Mater
- Loose brain covering
- Separated from the dura mater by the subdural space
- Has a wide subarachnoid space filled with CSF and large blood vessels
- Arachnoid villi help CSF to be absorbed into venous blood
Pia Mater
- Delicate connective tissue
- Clings to the brain
Cerebrospinal Fluid (CSF)
- Similar in composition to blood plasma, but with less protein and different ion concentration
- Provides buoyancy to the CNS
- Prevents brain from crushing under its own weight
- Protects the CNS from trauma
- Nourishes the brain and transports chemical signals
Choroid Plexuses
- Clusters of capillaries
- Form tissue fluid filters, which hang from the roof of each ventricle
- Alter ion concentrations of the CSF
- Remove CSF wastes
Blood-Brain Barrier
- Protective mechanism for maintaining a stable brain environment
- Separates bloodborne substances from neurons
- Nutrients pass freely
- Ineffective against substances that diffuse through plasma membranes
- Stress increases permeability
Spinal Cord
- CNS tissue enclosed within the vertebral column
- Extends from the foramen magnum to L1
- Two-way communication with the brain
- Protected by bone, meninges, and CSF
- Epidural space exists between the vertebrae and the dural sheath; filled with fat and veins
Spinal Cord Anatomy
- Conus medullaris is the terminal portion of the spinal cord
- Filum terminale is a pial extension that anchors the spinal cord to the coccyx
- Denticulate ligaments are pial shelves that attach the spinal cord to the vertebrae
- 31 pairs of spinal nerves attach to the cord by paired roots
- Cervical and lumbar enlargements accommodate nerves serving the upper and lower limbs
- Cauda equina is a collection of nerve roots at the inferior end of the vertebral canal
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Description
This quiz covers key concepts of the central nervous system, including its structure and embryonic development. It delves into the anatomy of the brain and spinal cord, highlighting cephalization and the development of the neural tube. Test your knowledge on how these elements work together to form the CNS.
