Place the steps of Excitation contraction in order of occurrence. I have given you the first step below: 1. The brain sends an action potential (nerve impulse) down a motor neuron to a muscle. [ Choose ] Calcium influxes into the axon terminus causing a release of the neurotransmitter acetylcholine (ACh) into the synaptic cleft Tropomyosin moves away from the active sites on the actin filaments. Myosin heads bind to actin forming cross-bridges. ATP is hydrolyzed to ADP and inorganic phosphate, which reenergizes the myosin head, preparing it for another cycle of cross- Depolarization triggers an action potential that quickly spreads along the sarcolemma and down into the muscle fiber through Myosin heads pivot toward the center of the sarcomere pulling the actin filaments toward the middle Receptors on the motor end plate of the muscle fiber's sarcolemma open causing an influx of sodium The sarcoplasmic reticulum releases stored calcium ions into the cytosol of the muscle cell. ATP molecule binds to the myosin head causing it to detach from the actin. Ca2+ binds to the troponin complex on the thin filaments of the muscle fiber.
Added by Jess R.
Step 1
Calcium influxes into the axon terminus causing a release of the neurotransmitter acetylcholine (ACh) into the synaptic cleft. Show more…
Show all steps
Your feedback will help us improve your experience
Kaela Piechowicz and 77 other Biology educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
What terms denotes a sudden change (depolarization and repolarization) in the electrical properties of the neuron membrane? Action potential Synaptic transmission Event-related potential Postsynaptic potential You step on a brick, ouch. What type of nerve will bring the signal from your foot to your brain? Somatic afferent Somatic efferent automatic afferent automatic afferent A given neurotransmitter is inhibitory. What might its receptors do? Allow positive ions to enter the cell Allow negative ions to enter the cell Allow positive ions to leave the cell B and C A very rostral coronal slice of the human brain is most likely to cut through The occipital lobe The frontal lobe The temporal lobe The parietal lobe The critical neural structures for initiating an action potential is The dendrites The synaptic terminals The soma The axon hillock. Early in an action potential, the inside of the axon becomes less negatively charged relative to the outside, this is called. Polarization Depolarization Hyperpolarization Repolarization Neurotransmitters -gated (ligand gated) ions channels are important for ____, while voltage gated ion channels are important for ____ Communication between neurons; communication within neurons communication within neurons; Communication between neurons In gross neuroanatomy we are interested in structures that are NOT visible to the naked eye. True or false.
Nicholas M.
Concern nerve impulses, electrical signals propagated along nerve fibers consisting of many axons (fiberlike extensions of nerve cells) connected end-to-end. Axons come in two varieties: insulated axons with a sheath made of myelin, and uninsulated axons with no such sheath. Myelinated (sheathed) axons conduct nerve impulses much faster than unmyelinated (unsheathed) axons. The impulse speed depends on the diameter of the axons and the sheath, but a typical myelinated axon transmits nerve impulses at a speed of about $25 \mathrm{~m} / \mathrm{s}$ much faster than the typical $2.0 \mathrm{~m} / \mathrm{s}$ for an unmyelinated axon. Figure P2.47 shows small portions of three nerve fibers consisting of axons of equal size. Two-thirds of the axons in fiber $\mathrm{B}$ are myelinated. Suppose that the nerve fibers in Figure $\mathrm{P} 2.47$ connect a finger to your brain, a distance of $1.2 \mathrm{~m}$. a. What are the travel times of a nerve impulse from finger to brain along fibers $A$ and $C ?$ b. For fiber $\mathrm{B}, 2 / 3$ of the length is composed of myelinated axons, $1 / 3$ unmyelinated axons. Compute the travel time for a nerve impulse on this fiber. c. When you touch a hot stove with your finger, the sensation of pain must reach your brain as a nerve signal along a nerve fiber before your muscles can react. Which of the three fibers gives you the best protection against a burn? Are any of these fibers unsuitable for transmitting urgent sensory information?
BIO Stimulating the Brain. Communication in the nervous system is based on the propagation of electrical signals called action potentials along axons, which are extensions of nerve cells (see the MCAT-style Passage Problems in Chapter 26 ). Action potentials are generated when the electric potential difference across the membrane of the nerve cell changes: Specifically, the inside of the cell becomes more positive. Researchers in clinical medicine and neurobiology cannot stimulate nerves (even noninvasively) at specific locations in conscious human subjects. Using electrodes to apply current to the skin is painful and requires large currents, which could be dangerous. Anthony Barker and colleagues at the University of Sheffield in England developed a technique called transcranial magnetic stimulation (TMS). In this widely used procedure, a coil positioned near the skull produces a time-varying magnetic field that induces in the conductive tissue of the brain (see part (a) of the figure) electric currents that are sufficient to cause action potentials in nerve cells. For example, if the coil is placed near the motor cortex (the region of the brain that controls voluntary movement), scientists can monitor muscle contraction and assess the connections between the brain and the muscles. Part (b) of the figure is a graph of the typical dependence on time $t$ of the magnetic field $B$ produced by the coil. In part (a) of the figure, a current pulse increases to a peak and then decreases to zero in the direction shown in the stimulating coil. What will be the direction of the induced current (dashed line) in the brain tissue? (a) $1 ;$ (b) $2 ;$ (c) 1 while the current increases in the stimulating coil, 2 while the current decreases; (d) 2 while the current increases in the stimulating coil, 1 while the current decreases.
Recommended Textbooks
Biology for AP Courses
Objective Biology for NEET
Introduction to General, Organic and Biochemistry
Transcript
Watch the video solution with this free unlock.
EMAIL
PASSWORD