Brain Part 2

From the illustrations above we can see that the there are 12 different pair of cranial nerves.

I the Olfactory Nerve; is responsible for smell.

II the Optic Nerve; is responsible for vision.

III the Oculomoter Nerve; is responsible for eye movement and for pupil dilation.

IV the Trochlear Nerve; is responsible for eye movement.

V the Trigeminal Nerve; process sensory information, such as touch and pain from the face and head and from the muscles that are used for chewing.

VI the Abducens Nerve; is also responsible for eye movement.

VII the Facial Nerve; is responsible for the interior 2/3rds of the tongue and is related to taste, as well as sensory information for the ears, and also controls the muscles that are used in facial expressions.

VIII the Vestibulocochlear Nerve; is responsible for hearing and balance.

IX the Glossopharyngeal Nerve; is responsible for 1/3rd of the taste in the tongue, responsible for processing sensory information from the tongue, the tonsils, and from the pharynx The pharynx is the segment/portion of the neck and throat that is also a part of the respiratory system. It also controls some muscles used in swallowing.

X the Vagus Nerve; is responsible for motor functions and the automatic functions of the viscera, which include the heart rate, various glands, and digestion.

XI the Spinal Accessory Nerve; is responsible for the control of muscles that are used during head movement.

XII the Hypoglossal Nerve; is responsible for controlling the muscles of the tongue.

The structure of the brain is made up of eight different regions, the Medullar, the Ponds, Cerebral Cortex, Cerebellum, Hypothalamus, the Thalamus, the Limbic System, and the Midbrain region.

The Medulla runs continuously throughout the spinal cord and contains ascending and descending neuron fiber tracks that relay information between the spinal cord and various parts of the brain. The medulla contains three critical centers. The first of which is the carioinhibitory center, which regulates the heart beat. The second is the respiratory center, which regulates the natural rhythm of breathing, and the third is the vasomotor center, which regulates the diameter of the blood vessels. The medulla originate out of five of the cranial nerves, VIII the vestibulocochlear, IX the glossopharyngeal, X the vagus nerve, XI the accessory, and XII the hypoglossal.

There are also various Pons in the structure of the brain. Their function is to bridge the connections of the spinal cord with the brain and with each other. The pons originate out of four cranial nerves, V the trigeminal, VI the abducens, VII the facial, and VIII the vestibulocochlear nerve. The pons also contains the pneumotaxic center, which is part of the respiratory center.

The Cerebral Cortex functions include the throat, thought, reasoning, perception, language, and voluntary movement. The cerebral cortex is a thin sheet of tissue that makes up the outer layer of the brain. Its thickness varies from 2 to 6 mm. The right and left sides of the cerebral cortex are connected with a thick array of nerve fibers that are referred to as corpus callosum. In the human anatomy the cerebral cortex looks like it has many bumps and grooves in it. These bumps are referred to as gyrus and the grooves are referred to as sulcus.

The Cerebellum operates balance, posture, and movement and is located behind the brainstem. The cerebellum is also divided into two hemispheres and has a cortex that surrounds these hemispheres. The brainstem provides function to ones breathing pattern, the heart rate, and the blood pressure. The brainstem is a general term for the area located between the thalamus and spinal cord. The thalamus is comprised and made up of a series of fibers that are then further subdivided into subparts. The thalamus has mutual functions. It carries blood supply to a number of arteries, including the inferolateral arteries, the polar and paramedian arteries and to posterior arteries, which are sub branches of the posterior cerebral artery. The thalamus also acts as a translator where variopus neuroligical input signals are processed into a reconizable form that is read by the cortex. It is also well to point out that the thalamic sensory signals reach one or several regions that are located deep inside the cortex. The thalamus also plays a key role in the regulation of sleep and the state of being awake as well as playing a major role in the level of awareness and sentitual arousal activity, lack of this operation is reconized as the state of comatosis, or the state of being in a coma.

Elements within the brain stem include the medulla, pons, tecum, reticular, formation, the tegmentum, the cerebral cortex, medullary body, and the basal
ganglia.

The Medulla Oblongata is considered to be the lower portion of the brainstem. It is located above the spinal cord, and below the Pons. The medulla is considered to be divided up into two portions. The first being an open port that is relatively close to the pons and the second is considered to be a closed port and is located further down on the spinal column.

The Pons are structures located on the brain stem. The pons are located above the medulla, but below the midbrain section of the central nervous system pons play a critical role in acting as the relays sensory information center between the cerebellum and cerebrum or between the spinal column and the brain.

The reticular are fibers that are made up of one or more very thin and delicately woven strands referred to as type III collagen, but for our purposes we will refer to them as thinly woven fiber strands. These fibers build a structured and highly developed ordered network of cellular connections as well as also provide a supportive network of fibers connected to neurons. These fibers then act as the relay system in which signals are transmited and carried from one point in the body to the next. Such as sensory information from the spinal colum to the brain.

The Cerebral Cortex sends electronic signals refered to as connections (efferents) and receiver connections (afferents) from mutual regions of the brain and spinal column, including the thalamus and basal ganglia. The body’s ability to have sensory stimulation arrives in the cerebral cortex through different thalamic nuclei. Such as in the case of touch, vision, and sound. The two hemispheres of the cerebral cortex receive information from the opposite sides of the body. For example, the right cortex on the right side of the brain receives information from the left side of the body and the left cortex side of the brain receives information from the right side of the body. This helps us determine which areas control cretin neurological movements and functions. It also helps us determine which areas of the brain that may be under greater pressure or have suffered damage.

The cortex is the outer 2 to 4 mm of the cerebrum it contains and consists of gray matter (cell bodies) and white matter (axons/myelin).

The Medullary Body is an inspiratory neuron that is located in the inspiratory center of the medula. Signals to the medullary neuron come from the peripheral chemoreceptors, the carotid body, the aortic body, and the central chemoreceptors. Its prime funtion is to regulate breathing and breathing patterns.

The Basal Ganglia is responsible for the control of voluntary muscle movement. The basal ganglia are groups that include the golbus pallidus, caudat nucleus, subthalamic nucleus, putamen, and the substania nigra.

The Golbus Pallidus is one of three nuclei that make up the basal ganglia and is divided into two sections, the globus pallidus externa and the globus pallidus interna. Its main function is to receive input signals from other nuclei that are associated to the nervous system and then acts as a transmitter through the globus pallidus interna to relay/send this information on to other nuclei and to the thalamus.

The caudat nucleus is a telencephalic nucleus that is located within the basal ganglia. The caudate nuclei’s are located near the center of the brain, located in each hemisphere and sit on top of the thalamus. The caudate nucles was once thought of as the primarily sorce involved with control and voluntary movement. It is now considered to be a crucial part of the brain's learning process and memory system.

The Subthalamic Nucleus is considered to be a small thin lens shaped nucleus and is a part of the basal ganglia system. The subthalamic nucleus is located next to the thalamus and is used to help stimulate and regulate impulse/signal flow to and from the brain and the spinal colum.

The Putamen is a portion/segment of the basal ganglia that forms the outer part of the lenticular nucleus and it plays a key funtional role in ones ability to have reinforced learning capabilities.
The Substania Nigra separates the pes (foot) from the tegmentum (covering). The substania nigra is a major portion of the basal ganglia system. It is responsible for the production of dopamine in the brain. The dopamine neurons are activated by unexpected stimuli, the stimuli act as primary rewards in the absence of predictive stimuli and during the process of learning.

The Hypothalamus is responsible for providing function to the regulation of the body temperature, hunger, thirst, emotions, the pituitary gland, and to the circadian rhythms, natural rhythmic patterns within the body. The hypothalamus also controls the autonomic nervous system; it regulates the reception and sensory impulses from the viscera, the internal organs of the body, and assists as an intermediary between the nervous system and the endocrine system and also is responsible for the regulation of food intake. The hypothalamus is made up of several different areas and it is located at the base of the brain. One of the important functions that the hypothalamus is responsible for is the regulation of the body’s temperature, it acts as a thermostat by sending regulating pulses to the brain to either warm or cool the body. When we are too hot the hypothalamus sends singles to the brain that allows the pours/capillaries in the skin to expand, this expansion of pours allows the blood to cool at a faster rate.