Nervous System Lecture 14 - Loc'n of Function 2(2)

Overview of the Nervous System

  • Lecture 14 focuses on the brain and the localization of function.

Brain Functional Areas

  • Primary Motor Cortex: Responsible for voluntary motor function.

  • Primary Somatosensory Cortex: Processes sensory information from the body.

  • Primary Auditory Cortex: Processes auditory information from the ears.

  • Primary Visual Cortex: Processes visual information from the eyes.

Key Figures in Neuroanatomy

Paul Broca

  • Known for identifying Broca's area, critical for speech production.

Carl Wernicke

  • Known for identifying Wernicke's area, important for language comprehension.

Major Brain Regions

  • Central Sulcus: Divides the frontal and parietal lobes.

  • Precentral Gyrus: Located in the frontal lobe; primary motor area.

  • Postcentral Gyrus: Located in the parietal lobe; primary sensory area.

Stroke (Cerebrovascular Accident - CVA)

  • Defined as a medical emergency where blood supply to the brain is interrupted.

Types of Stroke

1. Transient Ischaemic Attack (TIA)

  • Temporary blockage of blood flow to the brain; often called a mini-stroke.

2. Ischaemic Stroke

  • Occurs when an artery supplying blood to the brain is blocked.

3. Haemorrhagic Stroke

  • Results from blood vessels bursting in the brain, leading to bleeding.

Major Arterial Supply to the Brain

Common Carotid Artery

  • Primary artery supplying blood to the face and neck.

Internal Carotid Artery

  • Supplies blood to the brain.

External Carotid Artery

  • Supplies blood to the face and neck structures.

Branching Arteries

  • Ophthalmic Artery: Supplies the eyes and muscles around them.

  • Anterior Cerebral Artery: Supplies the frontal lobe.

  • Middle Cerebral Artery: Supplies the lateral portions of the frontal, parietal, and temporal lobes.

  • Posterior Cerebral Artery: Supplies the occipital lobe and parts of the temporal lobe.

  • Vertebral Arteries: Supply blood to the brainstem and posterior part of the brain.

  • Basilar Artery: Formed by the merging of the two vertebral arteries; supplies blood to the brainstem and cerebellum.

Neurological Effects of Stroke

Anterior Cerebral Artery Impairment

  • Weakness or paralysis and loss of sensation affecting the contralateral leg.

Middle Cerebral Artery Impairment

  • Weakness or paralysis and loss of sensation affecting the contralateral arm and face.

  • Left Side Damage: May result in aphasia (language impairment).

  • Right Side Damage: Results in hemi-inattention (neglect of one side).

Posterior Cerebral Artery Impairment

  • Can cause visual disturbances, such as scotoma (blind spot).

Lateralization of Brain Function

  • Left Hemisphere: Primarily processes information from the right side of the body; associated with logical and analytical thinking.

  • Right Hemisphere: Processes information from the left side of the body; involved in creative and spatial tasks.