DPT 6240 - Brain Part 2 Study Notes

DPT 6240 - Brain Part 2 Notes

Course Objectives

The objectives for this section of the course are as follows:

  1. Identify the lobes and sections of the brain and brainstem.

  2. Describe the general functions of the cerebrum, brainstem, cerebellum, and diencephalon.

  3. Identify the ventricles and their locations.

  4. Identify the main arterial supply to the brain and brainstem.

  5. Describe the venous drainage of the brain.

  6. Describe the three meningeal layers and spaces.

  7. Discuss the function of the lobes related to the movement system.

  8. Discuss the function of the brainstem and cerebellum in relation to the movement system.

  9. Discuss the relevance of the arterial supply to regions of the brain.

Ventricles

Overview

  • The brain contains essential structures known as ventricles that are responsible for producing and containing cerebrospinal fluid (CSF).

Types of Ventricles

  1. Lateral Ventricles

    • Posterior Horn: Located at the back of the lateral ventricle.

    • Inferior Horn: Extends into the temporal lobe.

    • Anterior Horn: Located in the frontal lobe.

  2. Third Ventricle

    • Located centrally and connected to the lateral ventricle via the interventricular foramen.

  3. Cerebral Aqueduct

    • A thin canal that connects the third ventricle to the fourth ventricle.

  4. Fourth Ventricle

    • Connects to the central canal of the spinal cord and has both lateral apertures and a median aperture that allow CSF to flow into the subarachnoid space.

Brainstem

Structures of the Brainstem

The brainstem is comprised of the midbrain, pons, and medulla. It serves several critical functions and houses the nuclei of cranial nerves.

  1. Midbrain: Involved in motor control, vision, and auditory processing.

  2. Pons: Relays signals between the cerebellum and the cerebrum; involved in respiratory function.

  3. Medulla Oblongata: Controls autonomic functions such as cardiovascular and respiratory functioning, swallowing, and head and eye movements.

Reticular Formation

  • A collection of nuclei in the brainstem responsible for:

    • Arousal and Alertness: Regulation of wakefulness and sleep.

    • Autonomic Function: Control over vital involuntary functions.

Cerebellum

Functions of the Cerebellum

  • Responsible for coordination and fine-tuning of motor activities, including:

    1. Limb movement: Coordination of voluntary movements.

    2. Eye movement: Coordination of eye tracking and gaze stability.

    3. Swallowing: Coordination of the muscles involved in swallowing and speech production.

Diagrams

  • Refer to Lundy-Ekman Figure A-8 for visual representation of cerebellar function.

Arterial Supply

Circle of Willis

The arterial supply to the brain is organized around the Circle of Willis, with multiple branches:

  • Anterior Circulation:

    1. Anterior cerebral artery

    2. Middle cerebral artery

    3. Anterior communicating artery

    4. Internal carotid artery

  • Posterior Circulation:

    1. Vertebral artery

    2. Basilar artery

    3. Posterior cerebral artery

    4. Posterior communicating artery

Cerebellar Arteries

  1. Superior cerebellar artery

  2. Anterior inferior cerebellar artery

  3. Posterior inferior cerebellar artery

Lesions to Arterial Supply

Impact on Brain Functionality

  1. Anterior Cerebral Artery: Supplies the frontal and parietal lobes leading to:

    • Lower extremity involvement according to the homunculus.

    • Impairments in executive functioning, social interactions, and behavioral regulation.

  2. Middle Cerebral Artery: Also supplies the frontal and parietal lobes, causing:

    • Upper extremity involvement also according to the homunculus.

    • Possible deficits in language processing due to proximity to Broca’s area and Wernicke’s area.

  3. Posterior Cerebral Artery: Involves visual processing areas, leading to:

    • Visual deficits and disturbances in perception.

  4. Cerebellar Arteries: Lesions here result in coordination deficits leading to ataxia.

Comprehensive Understanding of Implications

  • Understanding these arterial supplies is crucial for developing effective rehabilitation strategies following cerebrovascular accidents or injuries.