Unit 5: Lecture 4 (Part 1: Midbrain & Hindbrain)

Brain stem

What is the most caudal part of the brain and connects the cerebrum with the spinal cord?

Midbrain, pons, and medulla oblongata

What are the three primary regions of the brainstem?

Mesencephalon

What is the midbrain derived from?

Metencephalon

What is the pons derived from?

Myelencephalon

What is the medulla oblongata derived from?

Midbrain

What part of the brain houses the superior and inferior colliculi, which are involved in visual and auditory reflexes, respectively, as well as the cerebral peduncles?

Pons

What part of the brain acts as the bridge between the cerebrum and the cerebellum, facilitating the coordination of voluntary movements?

Medulla oblongata

What part of the brain contains autonomic centers critical for cardiovascular and respiratory control?

True

(T/F) Lesions in the brain stem can lead to syndromes with mixed motor and sensory deficits, and often involve cranial nerve dysfunction.

True

(T/F) Damage to the brain stem can result in a characteristic pattern of 'crossed findings,' where motor or sensory deficits occur on the opposite side of the body relativ to the lesion, but cranial nerve deficits appear on the same side as the lesion.

Mesencephalon (midbrain)

What is the most rostral region of the brainstem and lies between the diencephalon and pons?

Substantia nigra

What part of the brain contains dopaminergic neurons, where degenerations can cause Parkinson's disease?

Substantia nigra

What pigmented basal ganglia structure in the ventral portion of the midbrain plays a crucial role in modulating motor activity and communicates directly with the striatum of the basal ganglia?

Tegmentum

What lies posterior to the substantia nigra and contains the red nucleus, which is involved in motor coordination, particularly related to the upper extremities?

CN III (Oculomotor) and CN IV (Trochlear)

What cranial nerves are housed in the mesencephalon (midbrain)?

Most eye movements and pupil constriction.

What are the cranial nerves that are housed in the mesencephalon (midbrain) responsible for?

Pons

What is located anterior to the cerebellum and superior to the medulla oblongata and contributes to both sensory and motor pathways through ascending and descending tracts?

CN V (Trigeminal), CN VI (Abducens), CN VII (Facial), and part of CN VIII (Vestibulocochlear)

What cranial nerves are housed by the pons?

Motor control of facial muscles, eye movement, mastication, and auditory and vestibular processing.

What are cranial nerves housed by the pons responsible for?

Middle cerebellar peduncles

What connects the pons to the cerebellum, serving as critical communication pathways for relaying information from the cerebral cortex to the cerebellum, particularly for voluntary motor control?

Pontine respiratory center

What is the network of nuclei in the pons

that modulates the rhythm and pattern of breathing? It plays a key role in smoothing the

transition between inhalation and exhalation by influencing the medullary respiratory centers.

True

(T/F) Lesions in the pons can result in both motor and sensory disturbances.

Cerebellum

What is part of the metencephalon, situated posterior to the pons and medulla oblongata and separated from them by the fourth ventricle? It is not part of the brainstem.

Vermis

What connects the two cerebellar hemispheres?

Cerebellum

What plays a critical role in motor control by receiving commands from the cerebrum and fine-tuning these motor signals before they are sent to skeletal muscles? It integrates proprioceptive feedback to assess body position, making real-time adjustments to maintain equilibrium and posture.

Cerebellum

What part of the brain supports motor learning and the consolidation of motor memory—often referred to as "muscle memory?"

Anterior inferior cerebellar artery (AICA), posterior inferior cerebellar artery (PICA), and superior cerebellar artery

What arteries supply the cerebellum?

Cerebellum

Lesions in what part of the brain can lead to ataxia, dysmetria, or dysdiadochokinesia, often resulting in loss of coordination without true muscle weakness? Such symptoms may follow infarction in cerebellar arteries or neurodegenerative conditions such as spinocerebellar ataxias.

Medulla oblongata

What is the most caudal part of the

brainstem, positioned between the pons and the spinal cord?

Pyramids

What part of the medulla oblongata are longitudinal ridges on the anterior surface of the medulla that contain motor projection tracts? These tracts descend from the cerebral cortex through the brainstem and spinal cord.

Inferior olivary nucleus (olive)

What part of the medulla oblongata are prominent bulge lateral to the pyramids, which contains the inferior olivary nucleus?

Relays ascending proprioceptive information—especially related to balance and movement—to the cerebellum.

What do the inferior olivary nucleus (olive) of the medulla oblongata do?

Medulla oblongata

What houses vital autonomic control centers, including the cardiac center, which regulates heart rate and strength of contraction; the vasomotor center, which regulates blood vessel diameter and hence blood pressure; and the medullary respiratory center, which controls the rate and depth of breathing?

Cardiac center, vasomotor center, and medullary respiratory center

What vital autonomic control centers are housed in the medulla oblongata?

Medulla oblongata

What contains nuclei involved in protective reflexes such as coughing, gagging, sneezing, and vomiting?

CN IX (Glossopharyngeal), CN X (Vagus), CN XI (Accessory), and CN XII (Hypoglossal)

What cranial nerves are housed in the medulla oblongata?

Each has motor and/or sensory functions crucial to swallowing, vocalization, parasympathetic regulation, and tongue movement.

What are the cranial nerves housed in the medulla oblongata responsible for?

Posterior inferior cerebellar artery (PICA) and a branch of the vertebral artery.

What arteries supply the medulla oblongata?

CN I (Olfactory) and CN II (Optic)

What are the only cranial nerves that do not come from the brain stem?

Left side

What side would be affected by a lesion on the right side of the brain stem?

Subconsciously processes visual information to initiate a involuntary motor response.

What are superior colliculus responsible for?

Fine motor control

What is the red nucleus in the mesencephalon responsible for?

Corpora quadrigemina

What is housed by the dorsal surface of the midbrain is formed by the tectum?

Superior and inferior colliculi

What are the two parts of the corpora quadrigemina?

Cerebellum

What part of the brain is a part of the mesencephalon, but not part of the brainstem?

Cerebellum

What part of the brain uses proprioceptive information to regulate body position?