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

1. forebrain

2. midbrain

3. hindbrain

1. telencephalon

2. Diencephalon

1. Thalamus

2. Hypothalamus

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.

4th ventricle

third ventricle

cerebral aqueduct

pineal gland

Hypothalamus

regulates body temperature

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

These are nuclei found in the posterior thalamus

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

1. pons

2. medulla oblongata

Via peduncles

• connect each section of the brainstem to the cerebellum

Superior cerebellar peduncle

• connects midbrain to the cerebellum

middle cerebellar peduncle

• connects pons to the cerebellum

Inferior cerebellar peduncle

• connects the medulla oblongata to the cerebellum

fine-motor movements

stroke to the cerebellum

• drunk syndrome

• slurred speech (sounds drunk)

• unable to perform fine motor movements

1. tectum

2. tegmentum

3. crus

1. Superior colliculus

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

2. Pretectal nuclei

   1. pupillary light refelex

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

cerebral spinal fluid

provides cushion to the cerebral aqueduct

assists with eye and head movement

1. pars compacts

2. pars reticulata

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

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

1. motor nuclei of CN VIII

2. Parasympathetic branch of CN VIII

1. Corticospinal tract

2. corticobulbar tract

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.

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.

1. tegmental

2. basilar

1. Vestibular nucleus

2. dorsal cochlear nuclei

   1. tenitis

   2. assists in localization

3. ventral cochlear nuclei

   1. speech processing

4. medial lemniscus

• 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

basilar portion

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

• Olfactory

• Cerebrum

• S

• Smell

• CN II

• Optic

• Cerebrum

• S

• Vision

• CN III

• Oculomotor

• Midbrain

• M

• Pupilary light refelex + looking up

• CN IV

• trochlear

• midbrain

• M

• Looking down and in

• CN V

• Trigeminal

• pons

• B

• sensation of face + muscles of chewing

• CN VI

• Abducens

• Pons

• M

• Look laterally

• CN VII

• Facial

• Pons

• B

• Muscles of facial expression + most of taste

• CN VIII

• Vestibularcochlear

• Pons

• S

• Hearing + vestibulation

• CN IX

• Glossopharyngeus

• medulla

• B

• swallowing muscles

• CN X

• Vagus

• Medulla

• B

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

• CN XI

• Accessory

• Medulla + Spinal Cord

• M

• Neck and shoulder muscles

• CN XII

• Hypoglossal

• Medulla

• M

• Tongue muscles

thalamus

the subarachnoid space

1. Vertebral system

2. carotid system

aka the posterior system

• comes from the subclavian system of the heart

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

they travel through the transverse foramen and magnum foramen

basilar artery

the vertebral arteries

1. Posterior Inferior Cerebellar Artery

2. Anterior inferior cerebellar artery

3. superior cerebellar artery

4. labyrinthine artery

pontine branches

• these supply blood to the pons

it splits into two branches

• posterior cerebral arteries

pontomedullary junction

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

Vertebral arteries

anterior spinal artery

Basilar artery

Posterior cerebral artery

posterior communicating artery

Anterior cerebral artery

Anterior communicating artery

posterior communicating artery

middle cerebral artery

pontine arteries

labyrinthine artery

Anterior inferior cerebellar artery

posterior inferior cerebellar artery

anterior spinal artery

vertebral artery

posterior cerebral artery

basilar artery

superior cerebellar artery

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

1. Anterior cerebral artery

2. middle cerebral artery

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

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.

circle of willis

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

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

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

• 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.

• Anterior 2/3 of spinal cord

• anterior spinal syndrome

  • paralysis down from point of occulsion

  • likely to occur between T4-L1

• posterior 1/3 of spinal cord

• paralysis down from point of occlusion

  • T1,2,3

• lateral medulla, posterior inferior cerebellum

• ataxia, vertigo, balance difficulty

• vertebral system

• Lateral Pons, Anterior Inferior Cerebellum

• ataxia, vertigo, balance difficulty

• vertebral system

• inner ear

• tinnitus, vertigo

• vertebral system

• superior cerebellum

• ataxia, vertigo, balance issues

• vertebral system

• midbrain + occipital lobe

• swallowing, vision problems

• Vertebral system

• Visual Centers

• Blindness

• carotid system

• frontal, temporal loves

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

• carotid system

• Parietal Lobes

• Proprioception

• Carotid System