Class Notes (906,189)
CA (538,602)
Western (51,554)
ANAT 3319 (925)
Lecture 8

Lecture 8.docx

12 Pages

Anatomy and Cell Biology
Course Code
Anatomy and Cell Biology 3319
Michele Barbeau

This preview shows pages 1-3. Sign up to view the full 12 pages of the document.
Lecture 8 Brain Stem & Cerebellum 3/10/13
Textbook: 378-385 ; 432-434
Brain Stem & Cerebellum Objectives:
Identify the 3 major subdivisions of the brainstem and describe the anatomic relationships of the
major motor and sensory nuclei and the major descending and ascending tracts in the brain stem
Know the main structures of connections of the cerebellum
Anatomical Components of the Brain Stem:
The brain stem is composed of the midbrain, pons and medulla oblongata
Nuclei: cranial nerve nuclei, visual and auditory reflex nuclei, pontine nuclei (motor, sensory,
Descending Tracts: form the cortex to pons, medulla and spinal cord; form hypothalamus
Ascending Tracts: from spinal cord and sensory cranial nerve nuclei
Motor Control Nuclei: substantia nigra, red nucleous
Reticular Formation: diffuse collections of neuronal cell bodies; sleep, wakefulness, autonomic
function, pain and muscle tension
Cerebellar Peduncles: large fiber tracts connecting the cerebellum to the rest of the brain
Ventricular System: cerebral aqueduct, fourth ventricle
Midsagittal Surface of the Brainstem:
Under the diencephalon is where the brainstem starts
First is the midbrain
The Cerebral aqueduct connects the third ventricle to the fourth ventricle
Underneath the midbrain is the pons (bridge), which contains fiber tracts connecting to the
ACB 3319
Lecture 8 Brain Stem & Cerebellum 3/10/13
Below the pons is the medulla which is continuous with the spinal cord
The fourth ventricle separates the cerebellum from the brainstem
Cerebral aqueduct
IV ventricle
Ventral/Anterior View of the Brainstem:
The optic chaism is where the fibers of the optic nerve cross over when going to the thalamus
Peduncle are different fiber tracts connecting the brainstem parts to the cerebellum
Mammillary bodies still cover some of the midbrain which are still attached to the hypothalamus
Cranial nevers are at the junction of the midbrain and pons as well as the junction between the
pons and medulla
Fibers on the surface of the pons are horizontal connecting the pons to the cerebellum (middle
cerebellar penduncle)
Cerebral peduncle fibers are vertical and carries information from the cerebral cortex for motor
function to the spinal cord
The fibers that continue down into the medulla from the cerebral peduncle from the pyramid and
crossing over of the fibers occurs and this is called decussation
The olivary nucleus is connected to the cerebellum
Lecture 8 Brain Stem & Cerebellum 3/10/13
Optic chiasm
Optic tract
Cerebral peduncle
Basal portion
of pons
Middle cerebellar
Olivary nucleus
Ventral median sulcus
Pyramidal decussation
Olfactory tract
Mammillary body
Temporal lobe
Posterolateral View:
Superior and Inferior Colliculi (2pairs), these are involved in specialized reflexes
This structure is called corpora quadrigemina
Superior colliculi is involved in motor reflex
Inferior colliculi is involved in auditory relfex
The pons contain the main fiber tracts that connects the brain stem to the cerebellum
Superior Cerebellar Peduncle connects midbrain to the cerebellum
Middle Cerebellar Peduncle connects the pons to the cerebellum
Inferior Cerebellar Peduncle connects the medullar to the cerebellum
On the dorsal surface is the 4th ventricle
Cuneate and Gracile fasciculus are ascending tracts from the spinal cord into the brain carrying
sensory information that terminates at the Cuneate and Gracile tubercle
ACB 3319

Loved by over 2.2 million students

Over 90% improved by at least one letter grade.

Leah — University of Toronto

OneClass has been such a huge help in my studies at UofT especially since I am a transfer student. OneClass is the study buddy I never had before and definitely gives me the extra push to get from a B to an A!

Leah — University of Toronto
Saarim — University of Michigan

Balancing social life With academics can be difficult, that is why I'm so glad that OneClass is out there where I can find the top notes for all of my classes. Now I can be the all-star student I want to be.

Saarim — University of Michigan
Jenna — University of Wisconsin

As a college student living on a college budget, I love how easy it is to earn gift cards just by submitting my notes.

Jenna — University of Wisconsin
Anne — University of California

OneClass has allowed me to catch up with my most difficult course! #lifesaver

Anne — University of California
Lecture 8 Brain Stem & Cerebellum 3/10/13 Textbook: 378­385 ; 432­434 Brain Stem & Cerebellum Objectives: Identify the 3 major subdivisions of the brainstem and describe the anatomic relationships of the  major motor and sensory nuclei and the major descending and ascending tracts in the brain stem Know the main structures of connections of the cerebellum  Anatomical Components of the Brain Stem: The brain stem is composed of the midbrain, pons and medulla oblongata  Nuclei: cranial nerve nuclei, visual and auditory reflex nuclei, pontine nuclei (motor, sensory,  autonomic) Descending Tracts: form the cortex to pons, medulla and spinal cord; form hypothalamus Ascending Tracts: from spinal cord and sensory cranial nerve nuclei Motor Control Nuclei: substantia nigra, red nucleous  Reticular Formation: diffuse collections of neuronal cell bodies; sleep, wakefulness, autonomic  function, pain and muscle tension  Cerebellar Peduncles: large fiber tracts connecting the cerebellum to the rest of the brain Ventricular System: cerebral aqueduct, fourth ventricle Midsagittal Surface of the Brainstem: Under the diencephalon is where the brainstem starts First is the midbrain The Cerebral aqueduct connects the third ventricle to the fourth ventricle Underneath the midbrain is the pons (bridge), which contains fiber tracts connecting to the  cerebellum  1 ACB 3319 Lecture 8 Brain Stem & Cerebellum 3/10/13 Below the pons is the medulla which is continuous with the spinal cord The fourth ventricle separates the cerebellum from the brainstem  Thalamus Pons Cerebellum IVventricle Midbrain Cerebral aqueduct Medulla Ventral/Anterior View of the Brainstem:  The optic chaism is where the fibers of the optic nerve cross over when going to the thalamus Peduncle are different fiber tracts connecting the brainstem parts to the cerebellum Mammillary bodies still cover some of the midbrain which are still attached to the hypothalamus  Cranial nevers are at the junction of the midbrain and pons as well as the junction between the  pons and medulla Fibers on the surface of the pons are horizontal connecting the pons to the cerebellum (middle  cerebellar penduncle) Cerebral peduncle fibers are vertical and carries information from the cerebral cortex for motor  function to the spinal cord  The fibers that continue down into the medulla from the cerebral peduncle from the pyramid and  crossing over of the fibers occurs and this is called decussation The olivary nucleus is connected to the cerebellum  2 Lecture 8 Brain Stem & Cerebellum 3/10/13 Olfactory tract Optic chiasm Mammillary body Tempora l lobe Optic tract Cerebral pedunc le     Basal port ion of pons Middle cerebellar pedunc le Olivary nucleus Ventral median sulcus Pyramidal decussation Pyramid (corticospinal) Posterolateral View:  Midbrain: Superior and Inferior Colliculi (2pairs), these are involved in specialized reflexes This structure is called corpora quadrigemina Superior colliculi is involved in motor reflex Inferior colliculi is involved in auditory relfex  Pons: The pons contain the main fiber tracts that connects the brain stem to the cerebellum Superior Cerebellar Peduncle connects midbrain to the cerebellum Middle Cerebellar Peduncle connects the pons to the cerebellum Inferior Cerebellar Peduncle connects the medullar to the cerebellum  On the dorsal surface is the 4  ventricle Medulla: Cuneate and Gracile fasciculus are ascending tracts  from the spinal cord into the brain carrying  sensory information that terminates at the Cuneate and Gracile tubercle 3 ACB 3319 Lecture 8 Brain Stem & Cerebellum 3/10/13 Thalamus Pulvinar Lateral geniculate a i Pineal Medial geniculate a e o rSuperior colliculi o duInferior colliculi C q Pons Superior cerebellar Middle cerebellar Peduncle (midbrain Peduncle (pons) & diencephalon) Inferior cerebellar Peduncle (medulla & spinal cord) Gracile tubercles Cuneate tubercle Dorsal median sulcus Cuneate fasciculus Gracile fasciculus Brainstem Cross­sectional Anatomy of Midbrain:  Periaqueductal gray matter receives pain signals an releases endorphins to suppress pain such as  when your playing sports  Red Nucleus is involved in motor control Substantia Nigra are neurons that release dopamine that goes to the striatum (part of the midbrain  and basal ganglia) Cerebral Peduncle are fivers projecting down from the cerebral cortex (descending fibers)  These fibers appear less in in the medulla but form the pyramidal decussation  Cranial Nerve 3 is the ocular motor  4 Lecture 8 Brain Stem & Cerebellum 3/10/13 Infe rior colliculus Periaque duc tal gra y Red nuc leus Subs tantia nigra Cerebra l pedunc le Cra nial Nerve III Cross Section Anatomy of the Pons: Here we can see cranial never 6 and 7 The Inferior/Middle/Super Peduncle are present (brainstem to cerebellum)  Pontine Nuclei block fibers from the cerebral peduncle (motor descending) and these continue on  to the corticospinal tract  Ce rebellar Supe rior cerebellar pedunc le nuc lei Infe rior Cerebellar pedunc le CN VII Middl e cerebellar pedunc le Pont ine Cort icospinal tract nuc lei CN VI 5 ACB 3319 Lecture 8 Brain Stem & Cerebellum 3/10/13 Corticoponto­Cerebellar Pathway: Corticoponto- cerebellar Pathway Internal capsule Cerebral peduncle Pontine nuclei Middle cerebellar peduncle Cross Section of the Medulla: Visceral Sensory Nuclei Nuclei of the solitary tract helps with blood pressure Dorsal nuclei of the vagus goes out to the heart and blood vessels Gracile and Cuneate Nuclei is where sensory information from the spinal cord terminates  Inferior Olivary Nucleus connects to the cerebellum 12 cranial nerve Pyramid is where all the cerebral penduncle fibers collect BEFORE they cross over We can see parts of the developing medulla forming from the alar and basal plate Alar plate give rise to sensory nuceli (gravile and cuneate nuclei) Basal plate give rise to motor nuclei such as the pyramid  6 Lecture 8 Brain Stem & Cerebellum 3/10/13 Gracile nuc leus Visceral sens ory nuc lei - dors al n. of the va gus Cune ate nuc leis (CN XII)s sal nuc leus Infe rior Oliva ry Cn XII nuc leus Pyra mid
More Less
Unlock Document

Only pages 1-3 are available for preview. Some parts have been intentionally blurred.

Unlock Document
You're Reading a Preview

Unlock to view full version

Unlock Document

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.