COSI 325 Neuroanatomy Pt.2 (brainstem, CN, and blood supply)

What are the three sections that the neural tube divided into?

1. forebrain

2. midbrain

3. hindbrain

What are the two parts of the forebrain?

1. telencephalon

2. Diencephalon

What are the two important structures of the diencephalon?

1. Thalamus

2. Hypothalamus

What does the thalamus do?

the thalamus is your body's information relay station. All information from your body's senses (except smell) must be processed through your thalamus before being sent to your brain's cerebral cortex for interpretation.

What structure is in green?

4th ventricle

What structure is outlined in pink?

third ventricle

What structure is outlined in purple?

cerebral aqueduct

What is the name of the structure labeled with a star?

pineal gland

What structure is in green?

Hypothalamus

What does the hypothalamus do?

regulates body temperature

• when someone is actively dying it is the fist to go —> person will experience fevers and chills

What are habenula nuclei?

These are nuclei found in the posterior thalamus

• they regulate serotonin (happy) and dopamine (move)

What two parts make up that hind brain?

1. pons

2. medulla oblongata

How does the brainstem communicate with the cerebellum?

Via peduncles

• connect each section of the brainstem to the cerebellum

What is the structure in green?

Superior cerebellar peduncle

• connects midbrain to the cerebellum

What is the structure in green?

middle cerebellar peduncle

• connects pons to the cerebellum

What is the structure in green?

Inferior cerebellar peduncle

• connects the medulla oblongata to the cerebellum

What is the cerebellum responsible for?

fine-motor movements

What is ataxia?

stroke to the cerebellum

• drunk syndrome

• slurred speech (sounds drunk)

• unable to perform fine motor movements

What are the three divisions of the midbrain? (superior to inferior)

1. tectum

2. tegmentum

3. crus

What two things are found in tectum of the midbrain? What are their functions

1. Superior colliculus

   1. visual reflex (like auditory reflex in the inferior colliculus)

2. Pretectal nuclei

   1. pupillary light refelex

What are the six things found in the tegmentum of the midbrain?

1. Cerebral Aqueduct

2. periaqueductal grey matter

3. medial longitudinal fasiculus (MLF)

4. Motor Nuclei of CN III Oculomotor

5. Parasympathetic Branch of CN III Oculomotor

6. Pars compacts of the substantia nigra

What runs through the cerebral aqueduct?

cerebral spinal fluid

what is the function of the periaqueductal grey matter?

provides cushion to the cerebral aqueduct

what does the medial longitudinal fasiculus (MLF) do?

assists with eye and head movement

What are the two parts that make up the substantia nigra?

1. pars compacts

2. pars reticulata

What is the function of the pars compacts section of the substantia nigra?

this is where dopamine is made

• when there is an issue with this structure —> parkinsons disease

• Dopamine is a neurotransmitter made in your brain. It plays a role as a “reward center” and in many body functions, including memory, movement, motivation, mood, attention and more

What is the function of the pars reticulata section of the substantia nigra?

this is where GABA is made

• GABA is an inhibitory neurotransmitter

• problems in this section can lead to anxiety and depression

• Benzodiazepines —> used to treat anxiety and depression by causing an uptake in GABA production within this area

What are the two parts of the oculomotor cranial nerve?

1. motor nuclei of CN VIII

2. Parasympathetic branch of CN VIII

What are the two tracts found in the crus of the midbrain>

1. Corticospinal tract

2. corticobulbar tract

What is the corticospinal tract responsible for?

The corticospinal tract controls primary motor activity for the somatic motor system from the neck to the feet. It is the major spinal pathway involved in voluntary movements.

What is the corticobulbar tract responsible for?

Corticobulbar tract carries upper motor neuron input to motor nuclei of trigeminal, facial, glossopharyngeal, vagus, accessory, and hypoglossal nerves. The motor component of trigeminal nerves supplies muscles of mastication. The facial nerve supplies the muscles of facial expression.

what are the two divisions of the pons?

1. tegmental

2. basilar

what are the 4 things found in the tegmental portion of the pons?

1. Vestibular nucleus

2. dorsal cochlear nuclei

   1. tenitis

   2. assists in localization

3. ventral cochlear nuclei

   1. speech processing

4. medial lemniscus

What type of nuclei are found in the basilar portion of the pons?

• pontine nuclei

  • travel contrallaterally

  • The reticular formation is a region in the pons involved in regulating the sleep-wake cycle and filtering incoming stimuli to discriminate irrelevant background stimuli

Where is the middle cerebellar peduncle connected in the pons?

basilar portion

What nuclei are found in the medulla? (superior to inferior)

1. Posterior cochlear nuclei

2. Anterior cochlear nuclei

3. hypoglossal nuclei

4. dorsal accessory olivary nuclei

5. principle olivary nuclei

6. medial accessory olivary nuclei

CN I (Name, Location of nuclei, S/M/B, Function)

• CN I

• Olfactory

• Cerebrum

• S

• Smell

CN II (Name, Location of nuclei, S/M/B, Function)

• CN II

• Optic

• Cerebrum

• S

• Vision

CN III (Name, Location of nuclei, S/M/B, Function)

• CN III

• Oculomotor

• Midbrain

• M

• Pupilary light refelex + looking up

CN IV (Name, Location of nuclei, S/M/B, Function)

• CN IV

• trochlear

• midbrain

• M

• Looking down and in

CN V (Name, Location of nuclei, S/M/B, Function)

• CN V

• Trigeminal

• pons

• B

• sensation of face + muscles of chewing

CN VI (Name, Location of nuclei, S/M/B, Function)

• CN VI

• Abducens

• Pons

• M

• Look laterally

CN VII (Name, Location of nuclei, S/M/B, Function)

• CN VII

• Facial

• Pons

• B

• Muscles of facial expression + most of taste

CN VIII (Name, Location of nuclei, S/M/B, Function)

• CN VIII

• Vestibularcochlear

• Pons

• S

• Hearing + vestibulation

CN IX (Name, Location of nuclei, S/M/B, Function)

• CN IX

• Glossopharyngeus

• medulla

• B

• swallowing muscles

CN X (Name, Location of nuclei, S/M/B, Function)

• CN X

• Vagus

• Medulla

• B

• heart rate regulation, blood pressure, laryngeal muscles (airway closure)

CN XI (Name, Location of nuclei, S/M/B, Function)

• CN XI

• Accessory

• Medulla + Spinal Cord

• M

• Neck and shoulder muscles

CN XII (Name, Location of nuclei, S/M/B, Function)

• CN XII

• Hypoglossal

• Medulla

• M

• Tongue muscles

What is the name of the structure in in pink?

thalamus

Where does do all the arteries run through?

the subarachnoid space

What are the two artery systems?

1. Vertebral system

2. carotid system

What is the vertebral system?

aka the posterior system

• comes from the subclavian system of the heart

• supplies blood supply to pons, medulla, cerebellum, occipital lobe

where do the paired vertebral arteries travel through?

they travel through the transverse foramen and magnum foramen

what do the paired vertebral arteries come together to form?

basilar artery

What artery supplies the two branches that come together to form the anterior spinal artery?

the vertebral arteries

What are the 4 arteries that can be found in the cerebellum?

1. Posterior Inferior Cerebellar Artery

2. Anterior inferior cerebellar artery

3. superior cerebellar artery

4. labyrinthine artery

What are the small arteries that come off the basilar artery?

pontine branches

• these supply blood to the pons

what does the basilar artery go on to form?

it splits into two branches

• posterior cerebral arteries

where do the vertebral arteries come together to form the basilar artery?

pontomedullary junction

What are the two spinal arteries? What portion of the spine does it supply?

1. posterior spinal artery

   1. posterior 1/3 of the spinal cord

2. anterior spinal artery

   1. supplies the anterior 2/3 of the spinal cord

What artery is in green?

Vertebral arteries

What is the name of the artery in green?

What is the name of the artery in green?

anterior spinal artery

What is the name of the artery in green?

Basilar artery

What is the name of the artery in green?

Posterior cerebral artery

What is the name of the artery in green?

posterior communicating artery

What is the name of the artery labeled A?

Anterior cerebral artery

What is the name of the artery labeled B? (click on picture and scroll to see which is labeled B)

Anterior communicating artery

What is the name of the artery labeled C?

posterior communicating artery

What is the name of the artery labeled D?

middle cerebral artery

What is the name of the artery labeled E?

pontine arteries

What is the name of the artery labeled F?

labyrinthine artery

What is the name of the artery labeled G?

Anterior inferior cerebellar artery

What is the name of the artery labeled H?

posterior inferior cerebellar artery

What is the name of the artery labeled I?

anterior spinal artery

What is the name of the artery labeled J?

vertebral artery

What is the name of the artery labeled K?

posterior cerebral artery

What is the name of the artery labeled L?

basilar artery

What is the name of the artery labeled M?

superior cerebellar artery

Where does the internal carotid artery travel through to get into the subarachnoid space of the brain?

first it travels through the carotid canal and then through the foramen lacerum to get into the subarachnoid space

Once in the middle cranial fossa, the internal carotid artery become what two terminal branches?

1. Anterior cerebral artery

2. middle cerebral artery

Why is the ophthalmic artery important?

this has blood supply for the eyes

• if there is plac or something that forms within cardiac system it can travel through the system and the 1st place it will go is the this artery and cause occlusion which leads to loss of vision in one or both eyes

What is the circle of willis?

The circle of Willis (cerebral arterial circle or circulus arteriosus) is an anastomotic ring of arteries located at the base of the brain. This arterial anastomotic circle connects the two major arterial systems to the brain, the internal carotid arteries and the vertebrobasilar (vertebral and basilar arteries) systems. It is formed by four paired vessels and a single unpaired vessel with numerous branches that supply the brain. 

The main function of the circle of Willis is to provide a collateral blood flow between the anterior and posterior arterial systems of the brain. Additionally, it offers the alternate blood flow pathways between the right and left cerebral hemispheres. This way the circle protects the brain from ischemia and stroke in cases of vascular obstruction or damage.

What structure is in green?

circle of willis

• incredible protective system —> it compensates for itself when there is an infarct

what is an ischemic stroke?

An ischemic stroke occurs when the blood supply to part of the brain is interrupted or reduced, preventing brain tissue from getting oxygen and nutrients. Brain cells begin to die in minutes. A stroke is a medical emergency, and prompt treatment is crucial. Early action can reduce brain damage and other complications.

• get to the hospital within 4.5 hrs you are able to be administered TPA which is a clot buster and will allow you to get better quicker

what is a hemorrhagic stroke?

A hemorrhagic stroke occurs when a weakened blood vessel ruptures and bleeds either inside or on the surface of the brain.

• mosy likely to not survive this one but if you do the rehab is faster than that of a ischemic stroke

what is a transient ischemic attack?

• lasts ~30 minutes

• when a clot moves and stops

A transient ischemic attack (TIA) is a temporary period of symptoms similar to those of a stroke. A TIA usually lasts only a few minutes and doesn't cause permanent damage.

Often called a ministroke, a TIA may be a warning. About 1 in 3 people who has a TIA will eventually have a stroke, with about half occurring within a year after the TIA.

Describe the Anterior Spinal Artery (coverage, CVA symptoms)

• Anterior 2/3 of spinal cord

• anterior spinal syndrome

  • paralysis down from point of occulsion

  • likely to occur between T4-L1

Describe the Posterior Spinal Artery (coverage, CVA symptoms)

• posterior 1/3 of spinal cord

• paralysis down from point of occlusion

  • T1,2,3

Describe the Posterior Inferior Cerebellar Artery — PICA (coverage, CVA symptoms)

• lateral medulla, posterior inferior cerebellum

• ataxia, vertigo, balance difficulty

• vertebral system

Describe the Anterior Inferior Cerebellar Artery (coverage, CVA symptoms)

• Lateral Pons, Anterior Inferior Cerebellum

• ataxia, vertigo, balance difficulty

• vertebral system

Describe the Labyrinthine Artery (coverage, CVA symptoms)

• inner ear

• tinnitus, vertigo

• vertebral system

Describe the Superior Cerebellar Artery (coverage, CVA symptoms)

• superior cerebellum

• ataxia, vertigo, balance issues

• vertebral system

Describe the Posterior Cerebral Artery (coverage, CVA symptoms)

• midbrain + occipital lobe

• swallowing, vision problems

• Vertebral system

Describe the ophthalmic Artery (coverage, CVA symptoms)

• Visual Centers

• Blindness

• carotid system

Describe the Middle Cerebral Artery (coverage, CVA symptoms)

• frontal, temporal loves

• broca’s aphasia, wernickes aphasia, loss of sound localization

• carotid system

Describe the Anterior Cerebral Artery (coverage, CVA symptoms)

• Parietal Lobes

• Proprioception

• Carotid System