2a. central nervous system Flashcards
What are the two main divisions of the nervous system?
The Central Nervous System (CNS) and the Peripheral Nervous System (PNS).
What structures are included in the CNS?
The brain and spinal cord.
What does the PNS consist of?
All neurons carrying information to (afferent neurons) or from (efferent neurons) the CNS.
What is the function of afferent neurons?
They carry sensory information from the body to the CNS.
What is the function of efferent neurons?
They carry motor information from the CNS to effectors (muscles or glands).
What is the basic structural and functional unit of the nervous system?
The neuron.
What are the three main parts of a neuron?
The axon, cell body, and dendrites.
What is the function of dendrites?
They carry information to the cell body.
What is the function of the axon?
It carries information away from the cell body.
What is the function of myelin?
It ensheathes many axons and increases the speed of action potential conduction.
What is Multiple Sclerosis (MS)?
A chronic disease causing plaques of demyelination and axon loss in the CNS.
What are common symptoms of MS?
Eye pain, visual deterioration, tingling in the limbs, and progressive disability.
Does MS affect the PNS?
No, it only affects the CNS.
What structure connects the two cerebral hemispheres?
The corpus callosum.
What are the three main divisions of the brain?
The forebrain, midbrain, and hindbrain.
What are the components of the forebrain?
The cerebrum, thalamus, and hypothalamus.
What structures make up the hindbrain?
The cerebellum, pons, and medulla.
What are the functions of the midbrain?
It controls eye movements and auditory processing.
What is the primary function of the cerebellum?
Motor coordination and motor learning.
What structures form the brainstem?
The midbrain, pons, and medulla.
What is the function of the medulla?
It controls vital functions like breathing and heart rate.
What is the role of the pons?
It plays a role in consciousness and posture.
What is the function of the thalamus?
It acts as a relay point for sensory information before it reaches the cerebral cortex.
What is the main function of the hypothalamus?
It maintains homeostasis by regulating body temperature, blood pressure, and fluid balance.
What part of the brain controls personality and motor function?
The cerebral cortex.
What are sulci and gyri?
Sulci are grooves in the brain; gyri are the raised areas between them.
Name the four lobes of the brain.
Frontal, parietal, temporal, and occipital lobes.
What is the function of the frontal lobe?
It controls voluntary movements and higher cognitive functions.
What is the function of the parietal lobe?
It processes sensory information such as touch and temperature.
What is the function of the occipital lobe?
It processes visual information.
What is the function of the temporal lobe?
It is involved in memory, emotion, hearing, and language.
What are the three layers of the meninges?
Pia mater, arachnoid mater, and dura mater.
Where is cerebrospinal fluid (CSF) found?
In the subarachnoid space.
What is the function of CSF?
It cushions and protects the brain and spinal cord.
What is the function of the spinal cord?
It acts as a highway for signals between the brain and the body.
What protects the spinal cord?
The vertebrae and meninges.
What is the vertebral canal?
A tunnel formed by stacked vertebrae that houses the spinal cord.
What is the function of ascending pathways?
They carry sensory information to the brain.
What is the function of descending pathways?
They carry motor instructions from the brain to the body.
What are the dorsal and ventral roots?
Dorsal roots carry sensory input; ventral roots carry motor output.
What is a lumbar puncture?
A procedure where CSF is withdrawn for analysis.
Why is a lumbar puncture performed below L3?
To avoid damaging the spinal cord.
What conditions can be diagnosed with a lumbar puncture?
Meningitis, brain haemorrhage, or stroke.
What is Multiple Sclerosis (MS)?
A chronic, relapsing/remitting disease affecting the central nervous system, characterized by plaques of demyelination and axon loss.
What are common early symptoms of MS?
Eye pain, visual deterioration, tingling in the limbs.
How does MS progress over time?
Initially, relapses show full functional recovery, but recoveries become more incomplete over time, leading to progressive disability.
Do all MS patients experience the same progression?
No, some have relapsing/remitting patterns, others have steady progression, and some may experience no progressive disability.
What is CSF and where is it found?
A clear fluid that bathes the CNS, found in the ventricles and subarachnoid space.
What produces CSF?
The choroid plexus, a specialized epithelium lining the brain’s ventricles.
How does CSF composition differ from blood plasma?
It has lower protein, cell, and most ion levels but higher sodium, chloride, and magnesium concentrations.
How is CSF reabsorbed into circulation?
Through arachnoid granulations into the venous system.
What are the three layers of the meninges?
Pia mater (innermost), arachnoid mater (middle), dura mater (outermost).
What is the function of the meninges?
To protect the CNS by cushioning it and separating it from the rest of the body.
Where is CSF found within the meninges?
In the subarachnoid space, between the pia and arachnoid mater.
What is the function of the ventricles in the brain?
They act as cavities that circulate CSF throughout the CNS.
What connects the lateral ventricles to the third ventricle?
The interventricular foramen.
What connects the third and fourth ventricles?
The cerebral aqueduct.
How does the fourth ventricle communicate with the subarachnoid space?
Via the lateral aperture (foramen of Luschka) and the median aperture (foramen of Magendie).
What is the primary function of the midbrain?
: Controls eye movements and is involved in the auditory system.
What is the function of the pons?
Involved in consciousness, posture, and connecting different brain regions.
: What is the function of the medulla?
Controls essential life functions like breathing and heart rate.
What are the three major columns of the spinal cord?
Dorsal column, lateral column, and anterolateral fasciculus.
What type of information does the dorsal column carry?
Sensory information related to fine touch and proprioception.
What type of information does the lateral column carry?
Mostly descending motor tracts from the cerebral cortex.
What type of information does the anterolateral fasciculus carry?
Sensory information related to pain and temperature.
What is the difference between ascending and descending pathways?
Ascending pathways carry sensory information to the brain, while descending pathways carry motor commands from the brain.
What is a lumbar puncture (spinal tap)?
A procedure to remove CSF from the subarachnoid space for diagnostic testing.
Why is a lumbar puncture performed below L3?
To avoid damaging the spinal cord, which ends around L1 in adults.
What is the cauda equina, and why is it important in lumbar punctures?
A bundle of spinal nerves floating in CSF, which can move out of the way of a needle.
What can CSF analysis detect?
Infections (e.g., meningitis with increased WBCs) or brain haemorrhage (with increased RBCs).
What is the function of intervertebral discs?
They act as shock absorbers and allow slight movement between vertebrae.
What are the two main components of an intervertebral disc?
The annulus fibrosus (outer ring) and nucleus pulposus (gel-like center).
What is the function of the annulus fibrosus?
It withstands compression and maintains the disc’s structure.
What is the function of the nucleus pulposus?
It distributes pressure evenly across the disc.
What is the main function of grey matter?
Processes information, contains neuron cell bodies, and is responsible for higher brain functions.
Where is grey matter found in the brain?
On the outer surface of the cerebral hemispheres (cerebral cortex).
What is the main function of white matter?
Consists of axons that form communication pathways between different brain regions.
Where is white matter found?
Deep inside the brain, beneath the grey matter, and in the outer regions of the spinal cord.
What are gyri?
Raised ridges between sulci that contain functional grey matter.
What is the function of sulci and gyri?
Increase the brain’s surface area to allow for more grey matter and cognitive processing.
What is the central sulcus?
A deep groove that separates the frontal and parietal lobes.
What is the function of the pre-central gyrus?
It contains the primary motor cortex, which controls voluntary movements.
What is the function of the post-central gyrus?
It contains the primary somatosensory cortex, which processes touch and sensory information.
Where do autonomic nerves run in relation to the spinal cord?
They run outside the spinal cord in a separate chain of neurons and ganglia.
