Central Nervous System Essay

This stage is called repolarisation. The K+ channels then close, the sodium-potassium pump restarts, restoring the normal distribution of ions either side of the cell surface membrane and thus restoring the resting potential. In response to this the Na+ channels in that area would open up, allowing Na+ ions to flood into the cell and thus reducing the resting potential of the cells. If the resting potential of the cell drops to the threshold level, then an action potential has been generated and an impulse will be fired.

The frontal lobe is located at the front of the brain and is associated with reasoning, motor skills, higher level cognition, and expressive language.

B ) (1) neurotransmitter released (2) diffused across the synaptic cleft to a receptor protein (3) binding of the transmitter opens pores in the ion channels and negative ions move in.

2. If the depolarization that reaches the axon is large and suprathreshold, the result in the axon is You correctly answered: c. action potentials at higher frequency.

When a membrane is excited depolarization begins. When the membrane depolarizes the resting membrane potential of -70 mV becomes less negative. When the membrane potential reaches 0 mV, indicating there is no charge difference across the membrane. the sodium ion channels start to close and potassium ion channels open. By the time the sodium ion channels finally close. The membrane potential has reached +35 mV. The opening of the potassium channels allows K+ to flow out of the cell down its electrochemical gradient ( ion of like charge are repelled from each other). The flow of K+ out of the cell causes the membrane potential to move in a negative direction. This is referred to as repolarization. ( Marieb & Mitchell, 2009). As the transmembrane potential comes back down towards its resting potential level and the potassium channels begins to close, the trasmembrane potential level goes just below -90mV, causing a brief period of hyperpolarization (Martini, Nath & Bartholomew, 2012). Finally, as the potassium channels close, the membrane turns back to its resting potential until it is excited or inhibited again.

1. Describe the structure of a neuron and explain the function of each of its major parts.

Dopamine limits and selects sensory information from the thalmus. The parietal lobe also deals with movement, along with orientation, recognition, and perception of stimuli. This cortical region is the main sensory area for the sense of touch, major inputs from the skin relay from the thalmus to the parietal lobe. All visual processes are carried out in the occipital lobe (true to its name), and the temporal lobe is associated with perception and recognition of auditory stimuli, memory and speech. The temporal lobe is responsible for deriving meanings for the appropriate retention of visual memories, language comprehension, and emotional association. Together these areas of the brain control the body through the CNS (central nervous system). Every bodily function needed to sustain life is initiated first through these primary sensory areas, making the brain of course the most important muscle in the

The frontal lobe is near the parietal lobe and is above and in front of the temporal lobe. The frontal lobes are linked to sensory and memory centers throughout the brain. Their primary job is to allow us to think things through and determine how to use information that is located elsewhere in the brain.

Depolarization in membrane potential triggers an action potential because nearby axonal membranes will be depolarized to values near or above threshold voltage.

The midbrain is located above the pons. The midbrain has an area called the substantia nigra which holds different nuclei. The midbrain is responsible for the body 's movement that is not covered by the cerebellum. The neurotransmitter dopamine, that produced by

The action potential is connected to the end of the axon, which is a tube that extends from the soma and branches out. The action potential starts where it ends at the end of the axon and travels down to the terminal button, which contains synaptic vesicles. The synaptic vesicles store neurotransmitters once they are synthesized. Once that is done, the neurotransmitters releases from the presynaptic neuron, this is the neuron that transmits the message, and sends a message to the postsynaptic neuron. After the action potential gets to the terminal button, voltage dependent calcium goes to the presynaptic membrane and opens while calcium comes into the cell. The calcium hen connects to the synaptic vesicles and causes the vesicles to break and

Human brain consists of billions of cells interconnected together, with each performing its separate functions. It consists of two explicit categories of nerves: neurons and glia cells. Neuron is a single nerve cell in the entire nervous system; which is electrically excitable cell that carries information after being processed via chemical or electrical signals. One of its key characteristics is that it does not undergo cell division. In addition, it maintains a voltage gradient for all the neurons across its membranes. Glia cells, on the other hand, its functionality is to maintain homeostasis.

lobe is responsible for your memory, emotions and personality. The ability for us to make decisions,

The nervous system is made up of basic units called neurons. The main role of the neurons is to receive, integrate and transmit information throughout the body. There are some neuroglial cells found in nervous system aswell which provide support to the neurons by giving protection and nourishment Neurons have nerve processes that looks like finger like projections extended from the nerve cell body. They also contain axons and dendrites which enable them to transmit signals throughout the body. Normally, axon carry signals away from the cell body and dendrites carry signals toward the cell body according to Regina Bailey (2013). Neurons have three different shapes: bipolar, unipolar and multipolar where bipolar has two neuronal processes coming out of the cell body, unipolar has only one neuronal process coming out of the cell body and multipolar has many neuronal processes coming out of the cell body.

The cranial nerves, spinal nerves and ganglia make up the PNS. The cranial nerves connect to the brain. The cranial and spinal nerves contain the axons (fibres) of sensory and motor nerve