Chapter 3.5 Brain Stem Flashcards
what does the brain stem consist of?
Pons
Medulla
Midbrain
*vital link between spinal cord and higher brain centres
What is the reticular network formation?
Receives and integrates all synaptic input
What is the reticular activating system?
Originate in the reticular formation and carries signals upward to arouse and activate the cerebral cortex
What are five functions of the brain stem?
- Majority of cranial nerves
- Contains centers that control Cardiovascular, respiratory, and digestive function
- Regulates postural muscle
- RAS: controls the overall degree of cortical alertness
- Plays a role in the sleep-wake cycle
What is the medulla oblongata?
-continuation of the superior part of the spinal cord (inferior part of the brain stem)
-contains nuclei to control vital functions:
—cardiac center (heart rate)
—vasomotor center (blood pressure via arteriole constriction)
—Respiratory center (controls rate and depth of breathing)
—Centers of reflex (sneezing, coughing, swallowing)
Medulla contains the nuclei of origin for 5 pairs of cranial nerves:
- vestibulocochlear (VIII) nerves - hearing
- Glossopharyngeal (IX) nerves - taste, swallowing and salivation
- Vagus (X) nerves - mixed (sensory and motor) nerve that is widely distributed from the neck into the thorax and abdomen
- Accessory (XI) nerves: cranial
- Hypoglossal (XII) nerves - tongue control
What is the pons?
Located between the midbrain and medulla
Pons associated with four cranial nerves
- Trigeminal (V)
- Abducens nerve (VI)
- Facial (VII)
- Vestibulocohlear (VII)
What is the midbrain?
Superior portion of the brain stem
—extends from pons to the diencephalon
What are cerebral peduncles?
Tracts in the midbrain
- motor neurons from cerebrum o spinal cord, medulla and pons
- sensory neurons from medulla to thalamus
What are the5 nuclei of the Midbrain?
- Tectum
- Substantial Nigra
- Red nuclei
- Mesencephalic nucleus
- Cranial nerves
