Anatomy Notes

4 Pages
Unlock Document

Western University
Anatomy and Cell Biology
Anatomy and Cell Biology 3319
Peter Merrifield

Anatomy NotesOct 611 In the brain there are two lateral ventricles one in each hemisphere Cerebral spinal fluid flows out here The third ventricle lies at the midline of the diencephalon The fourth ventricle separates the cerebellum from the brain stem The ventricles developed from the fluidfilled neural tube Anatomical components of the brain stem Midbrain pons medulla oblongata Nuclei cranial nerve nuclei visual and auditory reflex nuclei pontine nuclei motor sensory autonomic carry info in and out Descending tracts from cortex to pons medulla and spinal cord anterior horn from hypothalamus Ascending tracts from spinal cord and sensory cranial nerve nucleiMotor control nuclei substantia nigra red nucleus Reticular formation diffuse collections of neuronal cell bodies sleep wakefulness autonomic function pain muscle tensionCerebellar peduncles large fibre tracts connecting the cerebellum to the rest of the brain Ventricular system cerebral aqueduct fourth ventricle The brain stem lies in the posterior cranial fossa of the skull and has many functions It is a passageway for all the fibre tracts running between the cerebrum and the spinal cord It is involved in innervation of the face and head In a midsagittal view immediately under the diencephalon is the midbrain The cerebral aqueduct runs through the midbrain The pons is a bulbous projection The medulla terminates where the spinal cord begins The fourth ventricle separates the midbrain and cerebellum The cerebellum is located on the posterior aspect of the midbrainThe medulla is continuous with the spinal cord at the level of the foramen magnum of the skull There is a midline that separates the medulla into two halves This midline is called the median sulcus Flanking the midline are pyramids which are made up of pyramidal tracts These are large fibre tracts that descend through the brain stem and spinal cord carrying voluntary motor output from the cerebrum to the spinal cord These are also called corticospinal fibres Inferior to the midline is the pyramidal decussation which is where the pyramid fibres cross the midline The result of this crossing over is that each cerebral hemisphere controls the voluntary movements of the opposite side of the body The medulla is connected to the cerebellum dorsally by inferior cerebellar peduncles which are fibre tracts These structures make up the white matter of the medulla The gray matter consists of the olives The olives are lateral to the pyramids and contain an inferior olivary nucleus which is a wavy fold of gray matter This nucleus is a relay station for sensory information travelling to the cerebellum Proprioceptive information ascending from the spinal cord to the cerebellum goes through this nucleus The five most inferior pairs of cranial nerves attach to the medulla The sensory or motor nuclei associated with these cranial nerves lie near the fourth ventricle The vestibulocochlear nerve cranial nerve VIII is located between the medulla and pons and is the sensory nerve of hearing and equilibrium The glossopharyngeal nerve cranial nerve IX innervates the tongue and pharynx The vagus nerve cranial nerve X innervates visceral organs in the thorax and abdomen The accessory nerve cranial nerve XI innervates muscles of the neck The hypoglossal nerve cranial nerve XII innervates tongue muscles The reticular formation is a cluster of brain nuclei that are located in the medulla and run through the core of the brain stem These nuclei form three columns the midline raphe nuclei which are flanked by the medial nuclear group and the lateral nuclear group The most important nuclei located in the reticular formation are the cardiac centre the vasomotor centre the medullary respiratory centre and other centres that
More Less

Related notes for Anatomy and Cell Biology 3319

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.