L119 Functional Organization of CNS Flashcards
List in detail the components of the central nervous system?
Cerebrum, cerebellum, brain stem (midbrain, pons, medulla), hypothalamus, thalamus, limbic system, basal ganglia and spinal cord
Which neuronal components make up gray matter vs white matter?
Gray matter = neuronal bodies (somata) and glia
White matter = axons (myelinated) and glia
What is the purpose of a diffusion weighted MRI?
To show the white matter axon tracts and orientation (stripped away gray matter)
At which vertical point does the brain axis/dorsal orientation change 90 degrees?
Midway at the top of brainstem, the dorsal component of brain changes from the back of the head to the top of the head.
Describe the cerebrum?
Made of two hemispheres (left and right), split by the longitudinal fissure. Ridges (gyri) and grooves (sulci) found throughout surface. Surface layer is the cerebral cortex.
- What does the cerebral cortex do?
- Name each lobe?
- Describe the cellular structure?
It is the site of language, emotions, memory, and self-awareness.
Split into Frontal lobe, temporal lobe, parietal lobe, and occipital lobe.
Cortex has a superficial layer of gray matter over a core of white matter. Seven layers in total, each with characteristic neuronal shape and function. Pyrmidal neurons and interneurons. Left and Right hemisphere linked by corpus collosum.
What are Brodmann’s areas?
Areas of the brain distinguished by histology and sometimes function. Designed 100ya.
How are motor movements fine-tuned?
Cerebellum and Basal Ganglia compare what motor function you intended to do with what you actually did. Does the fine tuning to produce smooth movements.
Cerebellum receives the signals, transmits them to the basal ganglia which produces a ‘motor program’ then sends the signal back to cerebellum.
Damage to Cerebellum manifests as clumsiness.
Describe the embryological location as well as components of Basal Ganglia?
Damage/dysfunction/pathology of the basal ganglia can results in which diseases commonly?
Located in the telencephalon.
Consists of caudate, putamen, and globus pallidus.
(caudate + putamen = striatum)
Basal ganglia + the subthalamic nucleus = substantia nigra
Damage to basal ganglia can lead to Parkinson’s disease and Huntington disease.
Which part of the brain is the major sensory relay to the cortex?
Describe it’s structure/function.
The thalamus.
Part of the Diencephalon. Located at the core of the brain, bilaterally, within the area of the basal ganglia.
Consists of 12 subnuclei that function to:
- Relay all sensory information to specific areas of the cortex
- Relay non-sensory information from basal ganglia to specific areas of cortex
- Project globally to cortex to influence arousal/sleep
Which part of the brain controls homeostasis and the pituitary gland?
Hypothalamus. Located below the thalamus. Part of the Diencephalon. Consists of lateral–>medial–>paraventricular layers.
Controls temperature, blood volume and pressure, O2, ion concentration, pH and blood glucose. AND endocrine function of the pituitary.
What are the components and functions of the brain stem?
Located beneath thalamus. Consists of Pons, midbrain and medulla.
Controls facial muscles, sensation from face and head, cardiorespiratory control, AND arousal and sleep/wake cycle.
Name all the cranial nerves? What do they generally do?
- Olfactory
2.Optic - Oculomotor
- Trochlear
- Trigeminal
- Abducens
- Facial
- Auditory-vestibulor
- Glossopharyngeal
- Vagus
- Accessory (spinal)
- Hypoglossal
Mnemonic: Oh Oh Oh To Touch And Feel (a) Virgin Girl’s Vagina And Hymen
Can be purely motor, sensory, or mixed.
10 of these 12 provide sensory and motor supply to face.
Describe structure of the spinal cord?
White matter on the outside with a gray matter core (inverse of the brain). Gray matter resembles an H shape, has dorsal (posterior) horns and ventral (anterior) horns.
Connects to the Medulla and is enclosed in the vertebrae.
Begins at C1 and ends at around L1/L2.
Where does the spinal cord change in thickness? Why?
Widens at lower cervical and lumbar regions because it has more gray matter to service the motor/sensory activity of the arms/legs.
What makes up a spinal nerve?
Dorsal and Ventral root ganglion combine to form the spinal nerve.
Dorsal Root Ganglion carry sensory information (primary afferent nerves) and contain ganglion outside of the CNS.
Ventral Root Ganglion carry motor information (primary efferent nerves) and contain ganglion within the ventral horn.
What makes up a Peripheral Nerve?
Peripheral nerve contains both motor and sensory neurons. Thus, damage will cause both types of symptoms.
What is a dermatome?
These are areas of the skin that are innervated by a bilateral pair of dorsal root ganglia
What are the ventricles?
Hollow parts of the brain (inner hollow part of neural tube during embryology).
Lateral, Third, and Fourth ventricles are filled with CSF.
What is CSF?
Cerebrospinal fluid is an ultrafiltrate of plasma. Created by the vascular choroid plexus in the ventricles. CSF flows out of 4th ventricle.
Provides a buffer for the brain, allows buoying of the brains weight.
Where are the meninges? Function?
These are protective connective tissue layers lining the brain. Outtermost layer is the Dura Mater (thickest), then Arachnoid matter (fibrous), then Pia Mater (thinnest).
Subarachnoid space contains CSF fluid. CSF is resorbed by major veins at arachnoid granulations.
What are the functions of the Falx and Tentorium?
These are connective tissue layers. The Falx seperates the right and left hemispheres and runs within the longitudinal fissure.
The Tentorium seperates the cerebellum from the occipital lobe.
What is the Blood Brain Barrier?
Formed by endothelial cells of capillaries. Very tight junctions, only permitting transport by active transport.
***CSF is different from plasma.
