Central Nervous System Structures (Brain & Spinal Cord) Flashcards
The diameter of the spinal cord _________ as you move inferiorly.
decreases.
What are the 7 important anatomical landmarks of the spinal cord?
- Cervical enlargement.
- Lumbosacral enlargement.
- Conus medullaris.
- Filum terminale.
- Cauda equina.
- Posterior median sulcus.
- Anterior median fissure.
What are the 3 structures on the inferior end of the spinal cord?
- Conus medullaris.
- Filum terminale.
- Cauda equina.
The _____ _________ is the cone-shaped end of the spinal cord.
conus medullaris.
Describe the filum terminale:
Thread-like extension of the pia mater.
What is the caudae equinae?
The dorsal & ventral roots of the lowest spinal nerves.
Between which vertebrae would you perform a spinal tap?
L3 to L5.
Where do we insert the needle when performing a spinal tap?
The subarachnoid space
What are 3 purposes of a spinal tap?
- Sampling CSF for diagnosis.
- Injection of antibiotics, anesthetic, chemotherapy, etc.
- Measuring CSF pressure.
What is the function of the meninges?
Protection & covering of the brain & spinal cord.
What are the 3 layers of the spinal meninges, from most to least superficial.
- Dura mater (outermost).
- Arachnoid mater.
- Pia mater (innermost).
Where is the epidural space?
Between the dura mater & vertebral bones.
Where is the subdural space?
Between the dura mater & arachnoid mater.
Where is the subarachnoid space?
Between the arachnoid mater & pia mater.
Gray matter contains ______ ____ ______ while white matter contains _____.
neuron cell bodies (somas); axons.
The anterior gray horn has _____ functions while the posterior gray horn has _______ functions.
motor; sensory.
How many pairs of spinal nerves are there?
31 pairs.
What 2 branches do spinal nerves form?
The dorsal ramus & the ventral ramus.
The dorsal ramus deals with _______ functions while the ventral ramus deals with _____ functions.
sensory; motor.
Which spinal nerves have 2 additional branches?
All nerves from T1 to L2.
What are the 2 additional branches that only some nerves have?
White ramus & gray ramus.
The white ramus & gray ramus are collectively called the:
rami communicantes.
Spinal nerves supply specific regions of the skin known as __________.
dermatomes.
What is a nerve plexus?
A network of intersecting nerves serving the same part of the body.
What are the 4 nerve plexuses & where are they located?
- Cervical plexus: neck.
- Brachial plexus: armpit.
- Lumbar plexus: back.
- Sacral plexus: tailbone.
Sometimes, the lumbar & sacral plexuses are combined to form the ___________ plexus.
lumbosacral plexus.
What are the 5 steps of a reflex arc?
- Activation of sensory receptor.
- Information relayed to CNS.
- Info is processed.
- Activation of motor neuron.
- Response by effector.
What are the 4 ways we can classify reflexes?
- Development (innate of learned).
- Response (somatic or visceral/autonomic).
- Complexity (mono or polysynaptic).
- Processing site (spinal or cranial).
The _______ reflex is normal in adults, while the ________ reflex is only normal in infants (abnormal in adults).
plantar; Babinski reflex.
Folds in the brain are called ____ while grooves are called either _____ or ________.
gyri; sulci or fissures.
What separates the left & right cerebral hemispheres?
Longitudinal fissure.
What are the names of the 4 cerebral lobes?
- Frontal lobe.
- Parietal lobe.
- Occipital lobe.
- Temporal lobe.
What separates the frontal & parietal lobes?
The central sulcus.
What are the names of the 2 gyri surrounding the central sulcus?
The precentral gyrus & postcentral gyrus.
What separates the parietal & occipital lobes?
The parieto-occipital sulcus.
What are some functions that the left hemisphere is specialized in?
Speech, reading, writing, language, math, decision making.
What are some functions that the right hemisphere is specialized in?
Analysis of sensory info, spatial visualization, recognition of faces & voice inflections.
What are the 3 types of white matter fibres in the cerebrum?
- Association fibres.
- Commissural fibres.
- Projection fibres.
What do the basal ganglia do?
They control muscle tone for specific, fine body movements.
What are 3 functions of the limbic system?
- Establish emotional states.
- Link conscious functions of cerebral cortex with autonomic functions of the brainstem.
- Facilitate memory storage & retrieval.
The diencephalon is composed of which 2 structures?
Thalamus & hypothalamus.
What are ventricles?
CSF-filled cavities.
CSF is produced by:
ependymal cells of the choroid plexus.
What are 4 functions of CSF?
- Protect the brain & spinal cord.
- Provide support.
- Actively transport nutrients, vitamins & ions to CNS tissue.
- Actively transport wastes away from CNS.
What is the circulation path of CSF (9 steps)?
- CSF formed in choroid plexus of lateral vesicles.
- Interventricular foramen.
- 3rd ventricle.
- Aqueduct of midbrain.
- 4th ventricle.
- Lateral aperture, median aperture & central canal of spinal cord.
- Subarachnoid space.
- Flows around brain & spinal cord.
- Eventually enters circulation via arachnoid granulations.
Where are the 4 ventricles located?
1&2: in cerebral hemispheres.
3: in diencephalon.
4: between pons & cerebellum.
Ventricles 1 & 2 are also known as:
lateral hemispheres.
Ventricles 1 & 2 are separated by a partition called the:
septum pellucidum.
What are the 4 protective structures for the brain?
- Bones of the skull.
- Cranial meninges.
- CSF.
- Blood brain barrier.
What is the blood-brain barrier made out of?
Astrocytes.
When receiving sensory information during a reflex arc, what is the path that somatic sensations will take?
From exteroceptors & proprioceptors of the sensors → dorsal ramus → dorsal root ganglion → dorsal root → somatic sensory nuclei.
When receiving sensory information during a reflex arc, what is the path that visceral sensations will take?
From interoceptors of sensors → dorsal ramus → dorsal root ganglion → dorsal root → visceral sensory nuclei.
When sending out motor commands in a reflex arc, what path will somatic motor commands take?
Somatic motor nuclei → ventral root → ventral ramus → effectors.
When sending out motor commands in a reflex arc, what path will visceral motor commands take?
Visceral motor nuclei → ventral root white ramus → sympathetic (autonomic) ganglion → gray ramus → postganglionic fibres → effectors.
What are the 2 major arteries supplying blood to the brain?
Internal carotid & vertebral arteries.
The blood brain barrier is formed by endothelial cells interconnected by _____ junctions.
tight.
Why is the blood brain barrier important?
It isolates nervous tissue in the CNS from the general circulation & it is highly selective in terms of what compounds it will allow into the brain.
Where is the primary motor cortex?
Surface of precentral gyrus.
What is the function of the primary motor cortex and what cells perform this function?
Pyramidal cells (neurons) direct voluntary movements by controlling somatic motor neurons in the brainstem & spinal cord.
Where is the primary somatosensory cortex?
Surface of the postcentral gyrus.
What is the function of the primary somatosensory cortex?
Receive general somatic sensory info from special sense receptors.
Where is the visual cortex and what does it do?
Occipital lobe; receives visual info.
Where is the auditory cortex & what does it do?
Temporal lobe; receives hearing info.
Where is the olfactory cortex & what does it do?
Temporal lobe; receives info about smell.
Where is the gustatory cortex & what does it do?
Anterior portion of insula & adjacent portions of frontal lobe; receives info from taste receptors of tongue & pharynx.
What do association areas connect?
Sensory & motor regions.
What are the 2 functions of association areas?
Interpret incoming data or coordinate motor responses.
The neurons in the primary motor cortex must be stimulated by _____ neurons from _________ to be useful.
other; elsewhere.
The diencephalon surrounds the ______ ventricle.
3rd.
The ________ forms the superior wall of the diencephalon, while the ____________ forms the inferior part of its walls & floor.
thalamus; hypothalamus.
What is the function of the thalamus?
Relaying & processing sensory info.
What is the function of the hypothalamus?
Centres regulate emotions, autonomic functions & hormone production.
What is the infundibulum?
Narrow stalk connecting the hypothalamus to the pituitary gland.
What are the 3 components of the brainstem from most superior to most inferior?
Midbrain, pons, medulla oblongata.
What are 3 functions of the midbrain?
Processing visual & auditory info, controlling reflexes triggered by these stimuli & maintaining consciousness.
What are some functions of the pons?
Connecting the cerebellum to the brainstem, somatic & visceral motor control.
What are some functions of the medulla oblongata?
Connecting the brain to the spinal cord, relaying sensory info to the thalamus, regulating autonomic function.
The cerebellar cortex is composed of _____ matter.
gray.
The cerebellar cortex contains a layer of large, highly branched neuron cell bodies called:
Purkinje cells.
The cerebral cortex is highly convoluted because of:
folia - folds of the cerebellum surface.
What structure separates the anterior & posterior lobes of the cerebellum?
The primary fissure.
What is the vemis?
A narrow band of cortex separating cerebellar hemispheres along the midline.
What is the flocculonodular lobe?
A slender lobe lying between the roof of the 4th ventricle & the cerebellar hemispheres & vermis.
Which tract links the cerebellum with the nuclei in the midbrain, diencephalon and cerebellum?
Superior cerebellar peduncles.
What are the middle cerebellar peduncles attached to?
Transverse pontine fibres.
Also connect cerebellar hemispheres with sensory & motor nuclei in pons.
Which tract links the cerebellum with nuclei in the medulla oblongata and carries ascending & descending tracts from the spinal cord?
The inferior cerebellar peduncles.
What are the 2 major functions of the cerebellum?
- Adjusting postural muscles of the body by altering muscle tone & modifying motor centre activities in the brainstem.
- Programming and fine-tuning conscious & subconscious movements.
