Section 11: The Nervous System
Structure and Function
Neurons
I. Neurons: cells of the nervous system, specialized to conduct electric like impulses
II. Axons and dendrites: impulses enter the neuron only through the dendrites and leave only through the axon
III. Synapse: space between the axon of one cell and the dendrites of others
IV. Axons and dendrites in the periphery are covered with myelin, which acts as insulation
Neurotransmitters
I. Neurotransmitters: chemicals that enable messages (nerve impulses) to pass from one cell to another, if chemicals are not produced in the right amounts, the message pathway becomes confused or blocked
Nerves
I. Some axons and dendrites are long and others short. Axons and dendrites of many
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Certain activities are centered in each lobe.
In general the right side of the cerebrum interprets for and controls the left side of the body and vice versa.
II. Cerebellum: found beneath the occipital lobe of the cerebrum. It too has an outer layer of gray cell bodies; this portion of the brain coordinates muscular activities and balance.
III. Brain stem: the midbrain, pons, and medulla are located in the brain stem. They are composed mainly of axons and dendrites. These fibers serve as connecting pathways between the control centers in the cerebrum and cerebellum and the spinal cord. Control centers are found within the brain stem for involuntary movements of such vital organs as the:
Heart
Blood vessels
Lungs
Stomach
Intestines
The Spinal Cord
I. The spinal cord extends from the medulla to the second lumbar vertebra in the spinal canal, which is above the small of the back, a distance of about 17 inches. Nerves entering and leaving the spinal cord carry impulses to and from the control centers.
The Meninges
I. There are three membranes called meninges, they surround both the brain and the spinal cord, they are the dura mater, the arachnoid mate, and the pia mater
The dura mater is the tough outer covering
The arachnoid mater is the middle, loosely structured layer
Cerebrospinal Fluid
I. Ventricles are cavities within the cerebrum that are lined with highly vascular tissue.
II.
45.Cerebellum: the "little brain" at the rear of the brainstem; processes sensory input and coordinates movement output and balance.
Nerve cells are made up of things called neurons, the cell body of the neuron has a long tinny axon that is covered by something called a myelin sheath, the axons are what pass the information from neuron to neuron and other cells in the body. The axons have a cover to protect them called myelin, this is what allows the brain and spinal cord to communicate with each other (Lindhom, 2014).
The Cerebellum is the part of the brain at the back of the skull in the vertebrates. Its function is to coordinate and regulate muscular activity. The Cerebellum is located behind the top part of the brain stem, it is where the spinal cord meets the brain, the Cerebellum is made of two hemispheres. The Cerebellum receives information from the sensory systems, the spinal cord, and other different parts of the brain, and then it also regulates motor movements. The Cerebellum coordinates voluntary movements such as posture, balance, coordination, and speech, and then it results in smooth and balanced muscular
Connected to the brain stem and is located in the back of the brain is the cerebellum. The cerebellum is responsible for motor coordination and also some learning involving movement. Once someone learns a new motor action that information is held in the cerebellum.
Cerebrum: The cerebrum is the main part of the brain, which has two halves, or hemispheres. The right hemisphere controls the left side of the body and deals with things such as creativity, music, and art. While the left hemisphere of the cerebrum controls the right side of the body and is in charge of language, problem solving, and math. The cerebrum’s many tasks are carried out by its outer layer, or its cortex. This has distinct areas that have different roles. Motor areas trigger movement; sensory areas deal with the senses, while association areas clarify information.
According to Carlson (YEAR), neuron (nerve cell) is defined as,” the information-processing and information-transmitting element of the nervous system”. The shape and variety will depend on the specialized job they perform. The majority of neurons have in common in one form or another, the four structures or regions: the cell body or soma, axon, dendrites; and terminal buttons. The soma or the cell body contains the nucleus which regulates all cell activity. Dendrites is derived from the Greek work Dendron, for tree, because they resemble trees. The dendrite is attached to the cell body of the neuron which receives information and
The spinal cord and the brain are the main parts of the central nervous system. The spinal cord is aligned from the base of the brain, through the back, which allows the body to move and have sensation. The spinal cord contains dendrites, supporting cells, and axons, long nerve fibers, that attach to the brain to carry out messages. The axons have sheaths of insulation called myelin and the dendrites receive signals from other dendrites. Dendrites actually make
Whereas the spinal cord (often referred to as the brainstem) is the pathways that enables nerve impulses to reach their various destinations in the body. The central nervous system main function is to receive information from the different parts of the body, in which must be analysed and stored in order for it to send out instructions based on those pieces of information. The central nervous system’s main function is to coordinate the numerous organs and muscles required to perform the individual’s desired action(s) (Walker, 2005).
The cerebellum, the part of the brain that regulates and coordinates the movements of the body. It allows us to do things without thinking and helps with memory. While driving the cerebellum coordinates the left and right hand movement.
The nervous system operates using an electrochemical process (see Video Clip: The Electrochemical Action of the Neuron). An electrical charge moves through the neuron itself and chemicals are used to transmit information between neurons. Within the neuron, when a signal is received by the dendrites, is it transmitted to the soma in the form of an electrical signal, and, if the signal is strong enough, it may then be passed on to the axon and then to the terminal buttons. If the signal reaches the terminal buttons, they are signaled to emit chemicals known as neurotransmitters, which communicate with other neurons across the spaces between the cells, known as synapses.
22. The part of the lower brain located behind the pons that controls and coordinates involuntary, rapid, fine motor movement is called the cerebellum.
Neurons have a part called the dendrites and this is where the neuron fires a correct impulse to another neuron through the axon. Axon is a long projection that connects nerve cells.
fibres. Nerve cells are grouped together to form grey matter, which is found at the periphery of the
Even though the brain is the major control center if the body, its job would not be possible without the spinal cord. The spinal cord is the major organ that helps information travel between the body and the brain. Nerves branch in the peripheral system from, either the brain stem or spinal cord, each nerve attaches to a specific area of the torso and limbs it 's responsible for communication to and from those regions. There are three very important
The cortex consists of four sections, called "lobes". The frontal lobe is connected to reasoning, planning, speech, movement, emotions, and problem solving. The parietal lobe is associated with balance, recognizing, and movement. The occipital lobe is associated with vision. The temporal lobe is connected to hearing, memory, and speech. The cortex is highly wrinkled, making the brain more convenient, as this increases the brain's surface area, giving it more room for neurons. The cerebrum is divided into two hemispheres- the left hemisphere, and the right hemisphere. The right hemisphere is associated with creativity, and the left one is linked with logic. A bundle of nerve fibers, known as the corpus callosum connects these "hemispheres" (Brain Structures and their Functions). The cerebellum, which is also known as the "little brain", is similar to the cerebrum, since it also has two hemispheres and a highly folded surface. This part of the brain is linked with movement and balance. The cerebellum is assumed to be older than the cerebrum "evolutionarily" (Brain Structures and Their Functions). The brain stem controls basic life functions such as blood pressure, breathing, and heartbeat. Scientists say that the brain stem is the simplest part of the brain (Brain Structures and Their Functions).