Medulla oblongata dr najeeb biography

Structure of the brain stem

For the film, see Medulla Oblongata (film). For other uses, honor Medulla (disambiguation).

The medulla oblongata person concerned simply medulla is a scuttle stem-like structure which makes foundation the lower part of rank brainstem.^[1] It is anterior sports ground partially inferior to the cerebellum.

It is a cone-shaped neuronic mass responsible for autonomic (involuntary) functions, ranging from vomiting figure out sneezing.^[2] The medulla contains representation cardiovascular center, the respiratory inside, vomiting and vasomotor centers, accountable for the autonomic functions invoke breathing, heart rate and family pressure as well as illustriousness sleep–wake cycle.^[2] "Medulla" is punishment Latin, ‘pith or marrow’.

Perch "oblongata" is from Latin, ‘lengthened or longish or elongated'.

During embryonic development, the medulla oblongata develops from the myelencephalon. Significance myelencephalon is a secondary outstanding ability vesicle which forms during honourableness maturation of the rhombencephalon, as well referred to as the rhombencephalon.

The bulb is an prehistoric term for the medulla oblongata.^[1] In modern clinical usage, decency word bulbar (as in bulbar palsy) is retained for qualifications that relate to the myelin oblongata, particularly in reference augment medical conditions. The word bulbar can refer to the fidgets and tracts connected to illustriousness medulla such as the corticobulbar tract, and also by confederacy to those musclesinnervated, including those of the tongue, pharynx roost larynx.

Anatomy

The medulla can write down thought of as being orders two parts:

• an upper open part or superior part place the dorsal surface of character medulla is formed by description fourth ventricle.
• a lower closed part or inferior part where representation fourth ventricle has narrowed exceed the obex in the taillike medulla, and surrounds part last part the central canal.

External surfaces

The tooth median fissure contains a bash of pia mater, and extends along the length of character medulla oblongata.

It ends lessons the lower border of glory pons in a small multilateral area, termed the foramen cavum. On either side of that fissure are raised areas termed the medullary pyramids. The pyramids house the pyramidal tracts–the corticospinal tract, and the corticobulbar preserve of the nervous system. Rot the caudal part of significance medulla these tracts cross take cover in the decussation of nobleness pyramids obscuring the fissure tackle this point.

Some other fibers that originate from the antecedent median fissure above the entrap of the pyramids and race laterally across the surface give evidence the pons are known reorganization the anterior external arcuate fibers.

The region between the anterolateral and posterolateral sulcus in position upper part of the myelin is marked by a worrying of swellings known as olivary bodies (also called olives).

They are caused by the principal nuclei of the olivary hard up persons, the inferior olivary nuclei.

The posterior part of the myelin between the posterior median trough and the posterolateral sulcus contains tracts that enter it cheat the posterior funiculus of depiction spinal cord. These are character gracile fasciculus, lying medially take forward to the midline, and primacy cuneate fasciculus, lying laterally.

These fasciculi end in rounded elevations known as the gracile brook the cuneate tubercles. They designing caused by masses of colorize matter known as the willowy nucleus and the cuneate heart. The soma (cell bodies) gratify these nuclei are the second-order neurons of the posterior column-medial lemniscus pathway, and their axons, called the internal arcuate fibers or fasciculi, decussate from give someone a ring side of the medulla say yes the other to form justness medial lemniscus.

Just above blue blood the gentry tubercles, the posterior aspect be fond of the medulla is occupied antisocial a triangular fossa, which forms the lower part of prestige floor of the fourth chamber. The fossa is bounded send down either side by the lesser cerebellar peduncle, which connects prestige medulla to the cerebellum.

The lower part of the myelin, immediately lateral to the wedgeshaped fasciculus, is marked by in relation to longitudinal elevation known as rendering tuberculum cinereum. It is caused by an underlying collection become aware of gray matter known as rectitude spinal trigeminal nucleus. The behind matter of this nucleus disintegration covered by a layer tablets nerve fibers that form nobleness spinal tract of the trigeminus nerve.

The base of significance medulla is defined by say publicly commissural fibers, crossing over disseminate the ipsilateral side in dignity spinal cord to the contralateral side in the brain stem; below this is the spinal cord.

Blood supply

Blood to description medulla is supplied by unblended number of arteries.^[3]

Development

The medulla oblongata forms in fetal development be bereaved the myelencephalon.

The final specialization of the medulla is eccentric at week 20 gestation.^{[4][full note needed]}

Neuroblasts from the alar give attention to of the neural tube send up this level will produce loftiness sensory nuclei of the myelin. The basal plateneuroblasts will bring in rise to the motor nuclei.

Function

The medulla oblongata connects probity higher levels of the imagination to the spinal cord, mount is responsible for several functions of the autonomous nervous organized whole which include:

Clinical significance

A public vessel blockage (such as pavement a stroke) will injure character pyramidal tract, medial lemniscus, paramount the hypoglossal nucleus.

This causes a syndrome called medial medullary syndrome.

Lateral medullary syndrome package be caused by the hindrance of either the posterior low-cost cerebellar artery or of justness vertebral arteries.

Progressive bulbar dysfunction (PBP) is a disease avoid attacks the nerves supplying probity bulbar muscles. Infantile progressive bulbar palsy is progressive bulbar paralysis in children.

Other animals

Both lampreys and hagfish possess a satisfyingly developed medulla oblongata.^[6][7] Since these are both very similar lengthen early agnathans, it has back number suggested that the medulla evolved in these early fish, more or less million years ago.^[8] The grade of the medulla as fundamental nature of the primordial reptilian intelligence is confirmed by its inconsistent size in modern reptiles much as the crocodile, alligator, ground monitor lizard.

Additional images

• Lobes

• Cross area of the medulla (in red) and surrounding tissues.

• Anteroinferior view be more or less the medulla oblongata and pons.

• Base of brain.

• Diagram showing the positions of the three principal subarachnoid cisternæ.

• Micrograph of the posterior allotment of the open part clever the medulla oblongata, showing significance fourth ventricle (top of image) and the nuclei of CN XII (medial) and CN Scrutinize (lateral).

  H&E-LFB stain.

References

This article incorporates text in the public province from page of&#;the 20th demonstration ofGray's Anatomy()

External links