Pons

The Brain Stem

This is a great picture of what has formally been called the brainstemThe lower part of the brain that connects to the spinal cord and controls vital functions.. It is now called the diencephalonA brain region that includes the thalamus, hypothalamus, and epithalamus. metencephalon. You know what? You can use whatever cephalon word that you like. Whatever you collectively call these units does not diminish from the factA statement based on direct observation that is repeatedly confirmed. that they act separately. From superiorAbove or toward the upper part of the body. to inferiorBelow or toward the lower part of the body. we have the midbrainThe upper portion of the brainstem involved in visual and auditory processing. the ponds and the medulla oblongataThe lowest part of the brainstem controlling vital functions like breathing and heart rate.. You can see that the medulla oblongata transitions into the spinal cordThe central nervous system structure that relays signals between the brain and body. at its inferior most border. The blue areas in this diagram are the 4th ventricle and the cerebral aqueduct. This open area contains cerebrospinal fluid(CSF) – A fluid that cushions and nourishes the brain and spinal cord.. It is continuous with the central canalA hollow canal in an osteon containing blood vessels and nerves.. We’ve been familiar with this in cross sections of the spinal cord.

Pons Anatomy

The word ponsA part of the brainstem that connects the cerebrum to the cerebellum and helps regulate breathing. means bridge.  Most of the information funneled through the pons concerns your somatic tissues or your skeletal muscle. It is information that controlsVariables that remain constant to ensure a fair test. these skeletal muscles subconsciously. The pons is concerned with somatic movements. It serves as a major connection between the cerebellumThe brain region responsible for balance, coordination, and fine motor control. and the midbrain. It also connects the cerebellum and the basal nucleiClusters of neurons in the brain that help regulate movement and coordination..  I have two transverse sections of the pons here 1 superior and 1 inferior. You can see the open area of the pons. In the superior transverse section A cut or slice of the body or an organ for study., it would be the cerebral aqueduct. In the inferior section, it would be a structure transitioning into the central canal of the spinal cord. As with pictures of the spinal cord dorsalRelating to the back side of the body. or posterior is here and ventralRelating to the front or belly side of the body. or anteriorThe front of the body or toward the front when standing in the anatomical position. is here.

Pons Gray Matter

 These two bumps coming off the dorsal side of the superior transverse section are called the cerebellar peduncles. The word peduncle just means foot. These are physical structures on which the cerebellum rests. They are also on myelinated neuronsThe functional cells of the nervous system that transmit signals. connecting the cerebellum to either the midbrain or the basal nucleiClusters of neurons in the CNS responsible for processing information.. Their axons run through the cerebellar peduncles. Function of carrying unmyelinated neurons but also providing physical support for the lobes of the cerebellum. These cerebellar peduncles reduce in size as the pons transitions superiorly to inferiorly.

Nuclei or cell bodies are located on the ventral side of the pons in this superior transverse section. They are collectively called the pontine nuclei. These nuclei control the cardiac function as well as respiratory function. These neurons innervateTo invade a tissue with nervous tissue is to innervate it. your heart and the muscles of your lungs. They control their normal function but can also override and stimulate them as needed to respond to external stimuliChanges in the environment that are detected by sensory receptors.. Within the pontine nuclei are individual cell bodies. They can accelerate your breathing and increase the depth of each breath. They can also decelerate your heart and perform a whole bunch of other functions.

The 3rd and final grey matter structures in the pons are the cell bodies. They belong to cranial nervesNerves that arise from the brain and control head and neck functions. 5 through 8. This would be the trigeminal the abducens the facial and the vestibulocochlear cranial nerves.  These nerves have a variety of functions related to movements and sensory input from the facial area. They are also involved in stimulating salivary secretions and taking apart in control of urinary reflexesAutomatic responses to stimuli.

Pons White Matter

The white matterThe outer portion of the spinal cord made of myelinated nerve fibers that transmit signals. of the pons contains more than just these two tractsBundles of nerve fibers in the CNS that carry signals between brain regions.. However, these are the most important to note. Bing the corticospinal tracts are here on the ventral side of the pons. These tracts were descending motor tracts. They carry information from your conscious brain down to your skeletal muscles and the neuromuscular junctionThe connection between a motor neuron and a muscle fiber.. The upper motor neuronsNeurons that originate in the brain and control lower motor neurons. spread through this corticospinal tractA descending motor pathway controlling voluntary movements.. They end at the spinal segment or spinal level where the information needs to go. This output reaches the correct area in peripheral tissues. The spinothalamic tract, located more toward the center of the pons, is an ascending tract. It carries conscious sensory information to your thalamusThe brain’s relay center, sending sensory information to the cerebral cortex..