Week 3: The Brainstem Flashcards
the brainstem is the most ?
inferior portion of the brain, and also the thinnest.
anatomical function of the brainstem ?
connects the brain to the spinal cord.
what are the 3 regions of the brainstem ?
medulla oblongata, pons, midbrain
talk more about the medulla oblongata.
the medulla oblongata is the most inferior part of the brainstem, connecting to the spinal cord. the medulla oblongata is important for autonomic functions and control reflex centers for vomiting, coughing, sneezing, and swallowing.
what are the pyramids/decussation of pyramids.
the pyramids are two bulges located on the anterior side of the medulla oblongata. they cross over from one side of the central nervous system to the other which is called decussation of the pyramids. this results in the right side controlling the left side and the left side controlling the right side.
consists of lateral corticospinal tract axons and often linked with anterior corticospinal tract axons. the axons in these two pyramids contain all of the somatic motor activity for the body. all voluntary movement go through here.
what are olives/inferior olive nuclei ?
lateral to the pyramids, there are two bulges called olives. within each olive, are nuclei called inferior olivary nucleus. they take input from other parts of the brain/spinal cord and send it to the cerebellum.
- if you have damage or cancer in this area, you would lose the ability to hit a target with a ball.
what is a nucleus ?
a bundle of neural cell bodies in the central nervous system
more about the pons ?
the pons is located above the medulla oblongata. it can be broken down into an anterior and posterior region. the posterior region has two regions called pneumotaxic center and apneustic center that help control breathing.
in the anterior side, there are pontine nuclei which coordinate voluntary movement. the main function of the pons is breathing control and relay center between different parts of the brain.
more about the midbrain ?
the midbrain is the uppermost part of the brainstem. they contain cerebral peduncles on the anterior side that connect the cerebrum to the brainstem, specifically the midbrain. the midbrain plays a large role in motor control and visual/auditory reflexes.
superior colliculus and inferior colliculus ?
collectively both are called the tectum and located on the backside of the midbrain.
the superior colliculi are responsible for reflex centers for visual activity (reading).
the inferior colliculi are responsible for auditory reflexes. (looking towards a loud noise). aka startle reflex.
what is the reticular activating system ?
the reticular activating system RAS is a network of neurons located in the brainstem. its functions are: consciousness, sleep, arousal, preventing sensory overload.
