Blood Flow to the Brain and Cranial Nerves

Blood Flow to the Brain

• Major Arteries:
  • Carotid Arteries:
    • Internal Carotid Artery: Supplies the anterior and middle portions of the brain.
    • External Carotid Artery: Supplies the face and scalp.
  • Vertebral Arteries: Join to form the Basilar Artery, supplying the brainstem and posterior brain.
• Circle of Willis:
  • A network of arteries at the base of the brain that provides collateral circulation.
  • Includes:
    • Anterior Cerebral Arteries (connected by the anterior communicating artery)
    • Middle Cerebral Arteries
    • Posterior Cerebral Arteries (connected to internal carotids via posterior communicating arteries)
• Clinical Relevance:
  • Ischemic Stroke: Blockage in blood supply (commonly middle cerebral artery).
  • Hemorrhagic Stroke: Rupture of a blood vessel.

Cranial Nerves

• Mnemonic: "Oh, Oh, Oh, To Touch And Feel Very Green Vegetables, AH!" (Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal)
• Cranial Nerve Functions:
  • Some are Sensory (S), Motor (M), or Both (B). "Some Say Marry Money, But My Brother Says Big Brains Matter More"
  • I (Olfactory): Smell (S)
  • II (Optic): Vision (S)
  • III (Oculomotor): Eye movement, pupil constriction (M)
  • IV (Trochlear): Eye movement (superior oblique muscle) (M)
  • V (Trigeminal): Facial sensation, chewing (B)
  • VI (Abducens): Eye movement (lateral rectus muscle) (M)
  • VII (Facial): Facial expression, taste (anterior 2/3 of tongue) (B)
  • VIII (Vestibulocochlear): Hearing, balance (S)
  • IX (Glossopharyngeal): Taste (posterior 1/3), swallowing (B)
  • X (Vagus): Parasympathetic control (heart, lungs) (B)
  • XI (Accessory): Shoulder and neck movement (M)
  • XII (Hypoglossal): Tongue movement (M)
• Testing Cranial Nerves: Specific tests are listed for each nerve. Examples include smell tests, visual acuity, eye movement assessments, facial sensations, taste tests, hearing tests, balance assessments, swallowing and gag reflexes, shoulder strength tests, and tongue movement evaluations.

Explore the intricacies of blood flow to the brain, focusing on major arteries like the carotid and vertebral arteries. Learn about the Circle of Willis and its importance in providing collateral circulation. The quiz also covers cranial nerves with memorable mnemonics for easy recall.