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The nerve impulses quizlet
The nerve impulses quizlet
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The nervous system performs its functions as neurons (nerve cells that transmit nerve impulses) innervate muscle structures. For a muscle to contract, the nervous system must first receive sensory inputs. During this process, sensory neurons take nerve impulses from sensory receptors in the skin and other organs to the central nervous system (i.e. brain and spinal cord) in response to external and internal stimuli. For example, to open a book by arm muscle contraction, continual sensory input to the central nervous system from the eyes and hands must be made to inform the position of the book. In a neuron, the dendrites (short extensions) receive signals from sensory receptors or other neurons, and the signal pass to the cell body before reaching an axon (portion of a neuron that conducts nerve impulses). Nerve impulses from sensory receptors (distal end of the long axon of a sensory neuron) of eyes travel through the sensory neuron from the dendrite-like structures projecting from the peripheral (outside of the CNS) end of the axon to the CNS axon. The central nervous system then performs integration- it sums up the input it receives from all over the body before commanding the muscle contraction in the arm to proceed. In the brain, the cerebral cortex, or a thin but convoluted outer layer of gray matter that covers the cerebral hemispheres contains motor, sensory, and association areas that are important for muscle contractions. The primary motor area in the frontal lob is the beginning of skeletal muscles. Then the primary motor area sends signals to the cerebellum, which integrates them. The primary somatosensory area dorsal to the central sulcus in the parietal lobe is where the sensory information from the skin and skeletal muscles arrive. There, a primary visual area receives information from the eyes. Association areas are places where integration occurs. The somatosensory association area processes and analyzes sensory information from the skin and muscles. Through the processes in the CNS, the system decides whether to send the command for muscle contraction. At any time, integration with other sensory data might cause the CNS to command a different motion instead. Finally, motor neurons (muptipolar neurons with many dendrites and a single axon) carry nerve impulses from the central nervous system to the muscles, and cause them to contract.
Action potential, or nerve impulse, occurs after a threshold value, or the minimum change in polarity across the axomembrane that is required for an action potential.
In the beginning phases of muscle contraction, a “cocked” motor neuron in the spinal cord is activated to form a neuromuscular junction with each muscle fiber when it begins branching out to each cell. An action potential is passed down the nerve, releasing calcium, which simultaneously stimulates the release of acetylcholine onto the sarcolemma. As long as calcium and ATP are present, the contraction will continue. Acetylcholine then initiates the resting potential’s change under the motor end plate, stimulates the action potential, and passes along both directions on the surface of the muscle fiber. Sodium ions rush into the cell through the open channels to depolarize the sarcolemma. The depolarization spreads. The potassium channels open while the sodium channels close off, which repolarizes the entire cell. The action potential is dispersed throughout the cell through the transverse tubule, causing the sarcoplasmic reticulum to release
This report will explore the structure and function of skeletal muscle within the human body. There are three muscle classifications: smooth (looks smooth), cardiac (looks striated) and skeletal (looks striated). Smooth muscle is found within blood vessels, the gut and the intestines; it assists the movement of substances by contracting and relaxing, this is an involuntary effort. The heart is composed of cardiac muscle, which contracts rhythmically nonstop for the entire duration of a person’s life and again is an involuntary movement of the body. The main focus of this report is on skeletal muscle and the movement produced which is inflicted by conscious thought unless there is a potentially harmful stimulus and then reaction is due to reflex, as the body naturally wants to protect itself. Skeletal muscle is found attached to bones and when they contract and relax they produce movement, there is a specific process that the muscle fibers go through to allow this to occur.
Kinesiology can be defined as the study of mechanics of body movements, so I think that is very important to know the meaning of movement when studying kinesiology. Everything in kinesiology has to do with the movement. Every action the body takes is a movement which is what kinesiology is. You cannot be successful in the field of kinesiology no matter what you are doing if you do not understand what movement is. It is the study of human movement, performance, and function by applying the sciences of biomechanics, anatomy, physiology, and neuroscience. It looks at movement and which muscles are involved to create movement relating to strength exercising and sports technique. Movement is an act of changing physical location or position or of
The occurrence of action potential is a very short process. When action potential occurs in the neuron the sodium channels open along the axon and sodium comes in. Because the sodium is positive it make the inside of the axon positive. When both the inside and outside are comparative in charge the sodium storms rushing in and starts the depolarization of the action potential. After this happens the sodium channels begin to close and the potassium channels begin to ...
When a message comes to the brain from body parts such as the hand, the brain dictates the body on how to respond such as instructing muscles in the hand to pull away from a hot stove. The nerves in one’s skin send a message of pain to the brain. In response, the brain sends a message back dictating the muscles in one’s hand to pull away from the source of pain. Sensory neurons are nerve cells that carry signals from outside of the body to the central nervous system. Neurons form nerve fibers that transmit impulses throughout the body. Neurons consists of three basic parts: the cell body, axon, and dendrites. The axon carries the nerve impulse along the cell. Sensory and motor neurons are insulated by a layer of myelin sheath, the myelin helps
Contrast the differences between force and torque. Use each term to describe a particular aspect of a muscle’s contraction relative to a joint. (6 pts)
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.
Almost all animals have a nervous system. Neurons bundle together to form nerves. The purpose of the nervous system is to coordinate all activities of the body, and enables the body to respond and adapt to changes both inside and outside. The central nervous and the peripheral nervous systems are very similar but different at the same time. The CNS is made up of the brain and spinal cord and functions mainly to process information and determine the appropriate responses. The central nervous system receives sensory information, figures out a response, and initiates a motor response if appropriate. The CNS is protected by the skull, vertebral column, and a membrane. The spinal cord provides communication between the brain and the peripheral nerves
The muscular system is the set of all the muscles that make up the human body. It is an extensive system of muscles and nervous tissue, which is distributed all through the body. In total, the human body consists of approximately 650 muscles (Shier, Butler, Lewis, 2009). The muscular system is divided into three types of muscle: cardiac muscle, smooth muscle, and skeletal muscle (p.212).
Synaptic transmission is the process of the communication of neurons. Communication between neurons and communication between neuron and muscle occurs at a specialized junction called synapses. The most common type of synapse is the chemical synapse. Synaptic transmission begins when the nerve impulse or action potential reaches the presynaptic axon terminal. The action potential causes depolarization of the presynaptic membrane and it will initiate the sequence of events leading to release the neurotransmitter and then, the neurotransmitter attaches to the receptor at the postsynaptic membrane and it will lead to the activation of the postsynaptic membrane and continue to send the impulse to other neurons or sending the signal to the muscle for contraction (Breedlove, Watson, & Rosenzweig, 2012; Barnes, 2013).
The brain consists of both neurons and glia cells. The neurons, which are cells housed in a cell body called a Soma, have branches which extend from them, referred to as dendrites. From these dendrites extend axons which send and receive impulses, ending at junction points called synapses. It is at these synapse points that the transfer of information takes place.
[3] H. S. Milner-Brown, R. B. Stein, and R. Yemm. "The Orderly Recruitment of Human Motor Units during Voluntary Isometric Contractions." The Physiological Society 230th ser. (1973): 359-70. Web. 22 May 2014.
The three interconnected functions of the nervous system are sensory input, integration, and motor output. Sensory input is the conduction of signals from sensory receptors to the central nervous system. Integration is the analysis and interpretation of the sensory signals and the formulation of appropriate responses. The motor output function is the conduction of signals from the integration centers to effector cells, which performs the body’s responses. The central nervous system (CNS) consists of the brain and the spinal cord.
Nervous system is one of the major organ systems that is responsible for the coordination of biological activities inside the body through cells called neurons. It is composed of the brain and spinal cord which are surrounded by protective layers of bone and membrane tissues called meninges. There are two major divisions in the nervous system; first one is the central nervous system (CNS) and the other being the peripheral nervous system (PNS). The CNS is composed of the brain, spinal cord, and retina while the PNS includes the sensory neurons, ganglia, and connecting neurons. The nervous system applies control using nerves; almost as if sending a message by a telephone. The nervous system is fast due to its electrical nature. The nerve cells in this system are connected with each other in a complex manner where the neural pathways would be possible. Neural