Download M555 Medical Neuroscience Lab 1: Gross Anatomy of Brain, Crainal

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project

Document related concepts

Brain wikipedia , lookup

Skull wikipedia , lookup

Brain size wikipedia , lookup

Anatomical terms of location wikipedia , lookup

Transcript
M555 Medical Neuroscience
Lab 1: Gross Anatomy of Brain, Crainal Nerves and Cerebral Blood Vessels
Anatomical Directions
Terms like “dorsal,” “ventral,” “anterior” and “posterior” provide a means of locating structures
relative to the overall orientation of the nervous system.
Complications with those terms may arise for two reasons:
i) humans stand upright
ii) the CNS curves or flexes as it grows from the neural tube, and the forebrain structures
(telencephalon and diencephalon) are oriented somewhat differently than the brain stem (midbrain,
pons, medulla, cerebellum) and spinal cord.
This drawing shows the application of these terms to the human central nervous system.
Forebrain
Orientation
telencephalon
diencephalon
dorsal
superior
rostral
anterior
caudal
posterior
forebrain
brain stem
midbrain
pons
ventral
inferior
medulla
cerebellum
spinal cord
Brain Stem and Spinal Cord
Orientation
spinal cord
rostral
superior
ventral
anterior
dorsal
posterior
caudal
inferior
Axis of CNS
Part 2: Gross Anatomy of CNS
Cranial Nerves
There are twelve pairs of cranial nerves. Some are readily apparent; others are smaller and
sometimes just the portion near the brain remains, making them more difficult to identify. We’ll
cover the cranial nerves later in more detail. Some functions of the cranial nerves are included
here as a brief introduction. Finding and naming the nerves are more important now.
CN I Olfactory Nerve
The nerve is very short and is destroyed when the brain is removed from the skull. Although
the nerve is no longer present, structures associated with the nerve - the olfactory bulbs
and olfactory tracts - are easily seen.
CN II Optic Nerve
Typically, proximal stumps of these nerves are visible after removal of the brain from the
skull. Look for these associated structures - the optic tract and optic chiasm.
CN III Oculomotor Nerve
This nerve is associated with eye function. It is involved in constriction of the pupil and also
in certain eye movements.
CN IV Trochlear Nerve
This small nerve is also involved in movements of the eye. It is the only cranial nerve that
emerges from the dorsal surface of the brain stem rather than the lateral or ventral surfaces.
CN V Trigeminal Nerve
This large nerve carries sensory input from the face and motor commands for jaw muscles.
CN VI Abducens Nerve
This is the third cranial nerve involved in making eye movements.
CN VII Facial Nerve
This large cranial nerve is necessary for control of facial muscles as well as production of
tears and saliva. In addition, it carries much of the sensory information from taste buds.
CN VIII Vestibulo-Cochlear Nerve
This nerve carries auditory and vestibular input from the inner ear to the brain stem.
CN IX Glossopharyngeal Nerve
Cranial nerves IX, X and XI are found close together along the sides of the medulla above
the spinal cord. This nerve provides some control of a throat muscle and saliva production.
It carries a bit of sensory input from the tongue, surface of the head in the region of the ear
and from some taste buds.
CN X Vagus Nerve
Like CN IX, this nerve is involved in taste, touch, saliva production and control of muscles
in the throat, but it is best known for supplying parasympathetic output to organs in the chest
and upper abdomen.
CN XI Accessory Nerve
This unusual nerve arises at high cervical levels of the spinal cord, but enters the skull to
run with CNs IX and X. It supplies motor outout to the sternomastoid and trapezius muscles.
CN XII Hypoglossal Nerve
This nerve supplies muscles within the tongue and other muscles that help move the tongue.
Surface of the Brain
Locate the following structures.
diencephalon
spinal cord
medulla
telencephalon
pons
cerebellum
midbrain (mesencephalon)
Gyri, Sulci and Lobes on the Surface of the Cerebral Hemispheres
Locate the following landmarks on the surface of the cerebral hemispheres.
lateral sulcus
central sulcus
parietal-occipital sulcus
preoccipital notch
Using these landmarks, define the borders of these five major regions of cerebral cortex.
frontal lobe
parietal lobe
temporal lobe
occipital lobe
limbic lobe
Pull the edges of the lateral sulcus aside and try to catch a glimpse
of the cerebral cortex of the insula.
Locate the following structures on the surface of the cerebral hemispheres.
in the frontal lobe
frontal gyri
orbital gyri
precentral gyrus
precentral sulcus
in the parietal lobe
supramarginal gyrus
postcentral gyrus
angular gyrus
postcentral sulcus
superior and inferior parietal lobules
in the temporal lobe
superior temporal gyrus
transverse gyri on superior surface of superior temporal gyrus
superior temporal sulcus
middle and inferior temporal gyri
parahippocampal gyrus
uncus
in the occipital lobe
calcarine sulcus
Surface and Interior of the Brain Stem
medulla (medulla oblongata)
pyramid (a bundle of axons on anterior or ventral surface of medulla)
inferior olive (bulge indicating the location of inferior olivary nucleus)
obex
gracile and cuneate tubercles
facial colliculus
pons
white matter (axon bundles) within pons
pontine nuclei
midbrain (or mesencephalon)
tectal area (“roof”) of the mesencephalon
superior colliculus (“optic tectum”)
also called the “corpora quadrigemina”
inferior colliculus
tegmentum of the mesencephalon
cerebral peduncles (also called “crus cerebrii”)
cerebellum
lateral hemispheres of cerebellum
vermis of cerebellum
flocculonodular lobe of cerebellum
tonsil of cerebellum
middle cerebellar peduncle (
“penduncle” = another name for a large bundle of axons in brain)
fourth ventricle
approximate location of foramen of Luschka and Megendie (in fourth ventricle)
cerebral aqueduct
posterior commissure (at border of midbrain and diencephalon)
Medial Surface of the Forebrain
diencephalon
medial surface of thalamus
medial surface of hypothalamus
pineal gland
mammillary bodies (part of hypothalamus)
infundibulum (“stalk”) of pituitary gland
third ventricle
septum pellucidum
interventricular foramen
lamina terminalis
telencephalon
cingulate gyrus
cingulate sulcus
corpus callosum (including splennium and genu)
anterior commissure
lateral ventricles
basal ganglia or basal nuclei (in interior of cerebral hemispheres)
Cerebrovascular System
Two systems of arterial blood flow supply the CNS.
- the Internal Carotid System
- the Vertebrobasilar System
Internal Carotid System
Find the remaining part of the Internal Carotid Arteries at the base of the brain.
Anterior Cerebral Artery
Anterior Communicating Artery
Middle Cerebral Artery
Posterior Cerebral Artery
Posterior Communicating Artery
Vertebrobasilar System
Look for the Vertebral Arteries on the brain stem. If they are not present,
know where they are found.
Several smaller arteries branch from the vertebral arteries.
Anterior and Posterior Spinal Arteries and the Posterior Inferior Cerebellar Arteries.
Blood from the vertebral arteries enters the basilar artery.
Basilar Artery on the ventral surface of the brain stem.
From the basilar artery, blood distributes to
several smaller arteries:
anterior
communicating A
Anterior Inferior Cerebellar Artery.
Superior Cerebellar Artery.
anterior
cerebral A
Posterior Communicating Artery
middle cerebral A
circle of Willis
internal carotid A
posterior communicating A
posterior cerebral A
superior cerebellar A
anterior inferior cerebellar A
posterior inferior cerebellar A
vertebral A
Circle of Willis
A network of arteries in the vicinity of the optic chiasm forms an interconnecting network of vessels.
Blood enters the Circle of Willis from both the Internal Carotid and Vertebrobasilar Systems.
Blood Supply to the Cerebral Cortex
Three major arteries - the Anterior, Middle and Posterior Cerebral Arteries supply the forebrain.
Below are three views of the cerebral hemispheres. On the drawings, identify the regions supplied
by these three major arteries.
ACA
anterior
anterior
ACA
PCA
MCA
Lateral Surface
of Right Cerebral Hemisphere
PCA
Medial Surface
of Left Cerebral Hemisphere
anterior
ACA
lateral
MCA
PCA
Inferior Surface
of Right Cerebral Hemisphere
Cerebral Veins and Dural Sinuses
Blood passes from deep and superficial cerebral veins into a series of spaces (“sinuses”)
associated with the dura matter. Blood from the sinuses eventually enters the internal jugular veins.