the medulla or medulla oblongata is one of the three sections that make up the brain stem of the three sections that make up the brainstem it is the most inferior and is continuous with the pawns above and the spinal cord below the medulla has many important features and functions it is a conduit for many essential ascending and descending nerve tracts it houses a sentence that control vital functions of the body such as heart rate breathing and blood pressure and also contains the nuclei of four cranial nerves let's focus on the external anatomy of the medulla focusing on the anterior surface so this is the anterior surface of the medulla at the midline you'll find the anterior median fissure which is continuous along the length of the spinal cord As you move lateral from the midline there are two sulci the ventral lateral sulcus and the posterolateral sulcus you can find the pyramids here the pyramids are composed of bundles of motor fibers which make up the corticospinal tract the olives also appear as a pair of swellings like olives you eat however they are located lateral of the pyramids the olives contain the olivary nuclei which play an important role in movement coordination and movement related learning posterior to the olives are the inferior cerebellar head uncles which connect the medulla to the cerebellum the ventro lateral sulcus and the postural lateral circles also have cranial nerves coming out of them at the medulla the cranial nerves to remember are cranial nerves 9 10 11 and 12 so the last four now let's look at the external anatomy of the medulla on the posterior surface so the back of the medulla in order to appreciate the posterior surface of the medulla the cerebellum which normally connects to the back of the Mandela part of it must be removed like the anterior surface of the medulla the posterior surface also has a midline structure this is called the posterior median sulcus this is continuous below as the posterior median sulcus of the spinal cord the posterior median sulcus conveys sensory input from most things below the neck including the viscera lateral from the midline you find the gracilis tubercle and the cuneat tubercle the gracilis and cuneat tubercle contains essentially tracts that carry sensory information from the periphery to the brain mainly touch information that was the external anatomy of the mandala now let us focus on the internal anatomy in order to understand the internal structures of the medulla we are going to view the medulla in Cross sections and we're going to discuss the internal anatomy by discussing three levels of the medulla these are level of decoration of the pyramids level of decoration of the medial lemon Sky level of the olives and inferior cerebellar poduncles some also say there's a fourth level just below the ponds but we won't discuss that firstly we will discuss the most distal level of the medulla which is the level of decisation of the pyramids this level is then continuous with the spinal cord now the level of decoration of the pyramids as the name suggests in this level is the major decisation point of the descending mode of fibers because the pyramids carry your motor fibers from your brain to your periphery now decisation essentially means when the motor nerve fibers travel and move from one side to the other so for example from the left to the right or from the right to the left decasating within this level you can also find sensory tracts as well such as the spino cerebellar tract which carry unconscious proprioceptive information or the lateral spinal thalamic tract which carries information about temperature and pain to the brain there's also spinal tract for cranial nerve five next we will discuss the level of decussation of the medial laminiscus in this level we have the major decisation point of the medial Lemonis skull fibers the great sensory decoration the medial laminisco tract carries sensory information of touch and vibration along the posterior spinal cord to the medulla before the sensory fibers traveling from the spinal cord synapse with fibers at the nucleus gracilis and the nucleus cuneaters the fibers from the nuclear gracilis and cunitis then decasate at this level so moving from one side to the other side before moving up to the brain stem and traveling through to the thalamus and then to the sensory cortex in the brain again decisation means mood the nerve fibers moving from one side of the body to the other so from the right side to the left side the other sensory tracts include the spinal cerebellar tract and the lateral spinal thalamic tract as well as a spinal tract for cranial nerve number five just as before we also have the motor tracked at this level because remember the motor fibers are traveling within the pyramids but they will deficit in the level below there are nuclei at this level which include the nucleus gracilis and nucleus cuneatus which we mentioned there's a continuation of the spinal nucleus for cranial nerve five the accessory nucleus and the hypoglossal nucleus which carries cranial nerve number 12. lastly we will discuss the level of the olives and inferior cerebellar peduncles now this level is very structurally different both externally and internally compared to the previous two levels firstly at this level the central Canal has expanded into the fourth ventricle making this region the open medulla at this level the inferior cerebellum paduncles will join the brain stem to the cerebellum the motor tracts will travel through the pyramids just like before and they'll keep going down towards the level of the decisation of the pyramids there are sensory tracts here including the medial longitudinal fasciculus tract protective spinal tract the spinal cerebellar tract and the lateral spinal thalamic tract spinal tract for cranial nerve five important nuclei at this level include the Oliveira nucleus glossopharyngeal nucleus vagal nucleus continuation of the spinal nucleus of cranial nerve 5 continuation of the hypoglossal nucleus which is your cranial nerve 12. so those were the important levels of the medulla oblongata from the top that was the levels of the olives the level of the medial and minuscal decassation and then the level of the pyramid decisation for the motor tracts now there are other important centers so remember the medulla is the house for the nuclei of cranial nerves 9 10 11 and 12. the medulla also contains many other centers that are important for controlling vital functions of the body such as the heart rate breathing and blood pressure the respiratory Center is a group of nuclear that are located in the ponds and the medulla oblongata and then you have the Vaso motor Center which is important in controlling blood pressure this also lies within the medulla oblongata and is responsible for collecting you know information from the body which can then influence heart rate and everything else now the blood supply or the vasculature of the medulla is complex and is dependent on the level being viewed but essentially it includes the vertebral arteries which you know come up from branches of the aortic Arch the posterior spinal artery the anterior spinal artery and the posterior inferior cerebellar artery now all that information we have learned about the medulla oblongata the external the internal the important nuclei as well as the blood supply is important to understand some medullary lesion syndromes which will be discussed in a separate video so in summary the medulla oblongata is part of the brain stem and is continuous with the spinal cord below there are three main levels which include from the very top the level of the olives below that is the level of decoration of the medial and meniscal tract which carries sensory information to the brain and then below that you have the level of the decisation of the pyramids which is the decoration of the motor tracts from the brain to the peripheries thank you for watching foreign