When the cat licks my big toe Meissner corpuscle receptors are activated. Meissner corpuscle receptors pickup fine touch and vibrations. Spinal nerves of first order neuron conducts impulses from receptors of big toe to the fibular nerve, upwards towards the femoral nerve which is part of the lumbar plexuses and located around L2-L4. Axons of the first-order neurons reach the central nervous system within the dorsal roots of spinal nerves and sensory roots of cranial nerves. The axon carrying sensory information from the lower part of the body ascend within the fasciculus gracilis tract and synapse in the nucleus gracilis of medulla oblongata. Axon of the second order neuron cross over to the opposite side of brain steam; this crossing over is called decussation. …show more content…
The medial lemniscus tract is a collection of axon in the central nervous system that carry sensory information from medulla oblongata to the thalamus. The axon in the medial lemniscus tract synapse on third-order neuron in ventral nuclei of the thalamus and from there information is send to the primary sensory cortex of cerebral hemisphere. There are a total of 3 synapses made: the first is located in dorsal root ganglia of the lower half of body, second is made in the nucleus gracilis of medulla oblongata and the third is made in the ventral nuclei of
Heart (Cardiac Muscle) Cells. Question 1: Briefly describe, in 500 words or less, the normal structure and function of your chosen cell type. In your answer, discuss specific features of your chosen cell type, including cell organelles. Throughout the heart, cardiac muscle cells are connected together to form a large network from one end to the other.
G-protein-linked receptors are protein receptors, located in the plasma membrane of a cell, that work with G-proteins to activate a cell-signaling pathway. These receptors are structured similarly in most organisms, with seven α helices and specific loops for binding sites for signal molecules and G-proteins. When a signal molecule from the extracellular fluid attaches to the signal-binding site it activates the G-protein-linked receptor by changing its shape. When this happens, the G-protein, loosely attached to the cytoplasmic side of the cellular membrane, attaches to its binding side on the receptor protein. The inactive G-protein becomes activated when GDP is displaced by GTP, a molecule similar to ATP. When the signal molecule is released, the G-protein diffuses along the cell membrane and attaches to an inactive enzyme. This newly activated enzyme triggers the cellular response. When the protein detaches itself from the enzyme, it releases a phosphate group turning GTP back into GDP, making the G-protein inactive once again.
Rowland, Lewis P. (ed.): Merritt's Textbook of Neurology, eighth edition. Lea and Febiger. Philadelphia, 1959, pp. 630--631.
...t has been noted that the gate control theory proposed by Melzack and Wall in 1965 formed the foundation of understanding the process of pain signal transmission. The dorsal horn of the spinal cord is the region of the CNS that controls the passage of pain signals by means of opening and/or closing the gate. Pain can only be perceived if reaches the brain. Events that cause excitation such pain signals and the release of excitatory or facilitatory chemicals cause the gate to open whereas inhibitory events such as competing nerve impulses caused by rubbing trigger closure of the gate. The gate can also be closed due to descending inhibition enhanced by relaxation or the use of pain-relieving medication such as morphine. The brain stem is responsible for controlling the transmission of pain signals via the ascending and descending pain pathways.
Acromegaly is a pituitary gland disorder that is an unusual and rare disease that comes from the hypersecretion of growth hormone during adulthood. It is rare in that acromegaly occurs in about 5 cases per million per year (Lugo 2011). Acromegaly if often labeled as a prolonged metabolic condition that is characterized by steady enlargement or elongation of facial bones and extremities (Thibodeau, 2013). This paper will explain the disease and how it affects the body, how one who has the disease might act and how to diagnose the disorder, and how to treat the disorder and ways for prevention of acromegaly.
Let’s say that there is a mechanical sense. If someone touched your hand, your somatosensory system will detect various stimuli by your skin’s sensory receptors. The sensory information is then conveyed to the central nervous system by afferent neurons. The neuron’s dendrites will pass that information to the cell body, and on to its axon. From there it is passed onto the spinal cord or the brainstem. The neuron's ascending axons will cross to the opposite side either in the spinal cord or in the brainstem. The axons then terminates in the thalamus, and on into the Brodmann Area of the parietal lobe of the brain to process.
Touch---travels through spinal cord---into medulla---left side functions of the body is controlled by the right side of the brain and the right side of the body is controlled by the left side of the brain.
The brain is part of the central nervous system, which consists of neurons and glia. Neurons which are the excitable nerve cells of the nervous system that conduct electrical impulses, or signals, that serve as communication between the brain, sensory receptors, muscles, and spinal cord. In order to achieve rapid communication over a long distance, neurons have developed a special ability for sending electrical signals, called action potentials, along axons. The way in which the cell body of a neuron communicates with its own terminals via the axon is called conduction. In order for conduction to occur, an action potential which is an electrical signal that occurs in a neuron due to ions moving across the neuronal membrane which results in depolarization of a neuron, is to be generated near the cell body area of the axon. Wh...
Rowland, L. P., ed. Merritt’s Textbook of Neurology. 7th ed. Lea and Febiger. Philadelphia: 1984.
Dendrites are located on either one or both ends of a cell.The peripheral nervous system then takes the sensory information from the outside and sends the messages by virtue of neurotransmitters. Neurotransmitters are chemicals that relay signals through the neural pathways of the spinal cord. The neurotransmitter chemicals are held by tiny membranous sacs located in the synaptic terminals. Synaptic terminals are located at the ends of nerve cells. The release of neurotransmitters from their sacs is stimulated once the electrical nerve impulse has finished travelling along a neuron and reaches the synaptic terminal. Afterward, neurotransmitters travel across synapses thus stimulating the production of an electrical charge that carries the nerve impulse onward. Synapses are junctions between neighboring neurons. This procedure is reiterated until either muscle movement occurs or the brain picks up on a sensory reaction. During this process, messages are being transmitted from one part of the body onto the next. The peripheral and central nervous system are two crucial subdivisions of the nervous system. The brain and spinal cord make up the central nervous
The myelin sheath is a fatty substance that surrounds the axons of the nerves and provides protection. It allows messages to be sent rapidly and accurately to the axons from long distances (Serono, 2010). The axons are the part of the nervous system that allows electrical transmission of signals throughout the brain and spinal cord. Without these electrical transmissions, the body would not be able to function properly (Serono, 2010).
In each zone, impulses and reflexes travel until they reach nerve endings in the feet and the hands. These zones are believed to be meridians along which energy flows. Placing pressure on the nerve endings in the hands and the feet will affect the organs found in that particular zone (http://www.reflexology.org/aor/refinfo/healart.htm). As well as longitudinal zones throughout the body, there are also cross-reflex points. These cross-reflex points are corresponding points on the opposite side of the body which can be useful in administering reflexology treatment when pressure is not able to be placed on the reflex point....
Touch receptors are a type of mechanoreceptor because they are activated by mechanical perturbation of the cell membrane. The axon is located in either shallow or deep skin and may be encapsulated by specialized membranes that amplify pressure. When the appropriate type of pressure is applied to the skin, these membranes pinch the axon, causing it to fire. The action potential travels from the point of origin to the neuron's cell body, which is located in the dorsal root ganglion. From there, it continues through another branch of the axon into the spinal cord, even as far as the brainstem.
Action potentials are started at one end of the node, flow passively through the myelinated axon, and pop out the other side to jump to the next node. This jumping of action potentials is called saltatory.
[online] Available at: http://www.livescience.com/22665-nervous system.html [Accessed: 1 Oct 2013]. Reece, J. 2012. The. Campbell biology. San Francisco, CA. -.