Introduction To The Nervous System Flashcards
What is a funiculus?
A segment of white matter containing multiple distinct tracts. Impulses travel in multiple directions
What is a tract?
An anatomically and functionally defined white matter pathway connecting two distinct regions of grey matter. Impulses travel in one direction.
What is a fasciculus?
A subdivision of a tract supplying a distinct region of the body.
What is a nucleus?
A collection of functionally related cell bodies
What are association fibres?
Fibres which connect regions within the same hemisphere
What are commisural fibres?
Fibres which connect the left and right hemispheres or cord halves
What are projection fibres?
Fibres which connect the cerebral hemispheres with the cord/brainstem
What are the major functions of the midbrain?
Eye movements and reflex responses to sound and vision
What are the major functions of the pons?
Feeding and sleep
What are the major functions of the medulla?
Cardiovascular and respiratory centres
Contains a major motor pathway (medullary pyamids)
How is CSF produced, distributed throughout the brain and spinal cord and reabsorbed?
Produced in choroid plexus which is found within each of the ventricles. CSF flows from lateral ventricles—> interventricular foramen—> 3rd ventricle—> cerebral aqueduct—> 4th ventricle—> spinal cord + sub arachnoid space—> reabsorbed through arachnoid granulations into dural venous sinuses.
The right half of our vision is controlled by which occipital lobe?
The left occipital lobe
The superior part of our vision is carried by which radiation?
The inferior radiation
The inferior radiations travel through which lobe?
The temporal lobe
A lesion in the left inferior radiation will produce which type of visual loss?
Right upper quadrantonopia
A lesion in the right optic tract will produce what type of visual loss?
Left homonomous hemianopia
A lesion in the optic chiasm will produce what type of visual loss?
Bitemporal hemianopia
Why do you get macular sparing if the lesion is in the occipital lobe?
The part of the occipital lobe that supplies the macula is supplied by the middle cerebral artery whereas the rest of the occipital lobe is supplied by the posterior cerebral artery so in a PCA stroke there will be a contralateral hemianopia with macula sparing.
What is the accomodation reflex?
It is required for near vision There are 3 Cs- Convergence Constriction of pupil Convexity of lens
Cerebral cortex must be involved as it is relating to image analysis
How does the accomodation reflex work?
Once the information from the eye has reached the visual cortex it travels to the midbrain where it synapses with the oculomotor nerve. The oculomotor nerve causes the medial rectus muscle to contract causing covergence and it also causes relaxation of ciliary muscle and contraction of contrictor pupillae.
