Activity 1 Pre-Lab Quiz K+ inside a cell = 150 mM; K+ outside a cell = 5 mM Na+ inside a cell = 5 mM; Na+ outside a cell = 150 mM Stop & Think question What is the polarity of the resting membrane potential (voltage)? Negative What does it mean that the voltage just inside the membrane is negative? B Membrane of most cells contains K+ leak channels…..b What will happen to the resting membrane potential if the extracellular K+ concentration is increase? Less negative What happens
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potassium ions (as demonstrated in Activity 1.) What passive channels are likely found in the membrane of the olfactory receptor‚ in the membrane of the Pacinian corpuscle‚ and in the membrane of the free nerve ending? 11. What is meant by the term graded potential? 12. Identify which of the stimulus modalities induced the largest amplitude receptor potential in the Pacinian corpuscle. 13. Identify which of the stimulus modalities induced the largest amplitude receptor potential in the olfactory
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Exercise 3: Neurophysiology of Nerve Impulses: Activity 3: The Action Potential: Threshold Lab Report Pre-lab Quiz Results You scored 25% by answering 1 out of 4 questions correctly. 1. Axons are You correctly answered: d. long‚ thin structures that extend from a neuronal cell body. 2. Which of the following is easier? Your answer : b. intracellular recordings of the action potential Correct answer: a. extracellular recordings of the action potential 3. An action potential is usually initiated in
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channels‚ and more of the potassium channels are open. Activity 2 1. Define graded potential. How does your data show that stimulation of the olfactory receptor is graded? Graded potential are local changes in membrane potential or short duration. These can be depolarizing which are less negative or hyperpolarizing which are more negative. The data that I collected shows that the olfactory receptor is graded because the resting potential‚ peak value response‚ and the amplitude of response
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Activity 1 – The Muscle Twitch and Latent 1) Define the terms skeletal muscle fiber‚ motor unit‚ skeletal muscle twitch‚ electrical stimulus‚ and latent period. Skeletal Muscle Fiber: Skeletal muscle cells that are composed of hundreds to thousands of individual cells that produce muscle tension. These fibers are what move our bodies and generate muscle tension/force that enables us to have manual dexterity. Motor unit: consists of one motor neuron and all of the skeletal muscle fibers that
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PhysioEx 9.0 Exercise 3 Neurophysiology of Nerve Impulses A C T I V I T Y 1 The Resting Membrane Potential 1. Explain why increasing extracellular K_ reduces the net diffusion of K_ out of the neuron through the K_ leak channels. Increasing the extracellular potassium reduces the concentration gradient‚ and less potassium diffuses out of the neuron and into the cell. 2. Explain why increasing extracellular K_ causes the membrane potential to change to a less negative value.
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neuron communicates with other neurons using action potentials and neurotransmitters (Carlson‚ 2004). Neurotransmitters from the synaptic vesicle of the terminal button of a neuron can cause a graded potential. Unlike action potentials which are always depolarization‚ graded potentials may be either depolarization (excitatory) or hyperpolarization (inhibitory) (Kalat‚ 2007). Depending on whether the neurotransmitter hyperpolarizes or depolarizes the neuron‚ there are two basic postsynaptic potentials
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occurs in this area leads to the end-plate potential‚ where an action potential in motor neurons causes the release of acetylcholine. The acetylcholine diffuses into the muscle fiber membrane and changes the ions permeability that creates graded depolarization of the end-plate potential. The end-plate potential triggers events that create contraction of the muscle cell. 4. During the latent phase there is no muscle contraction. This phase is the period of time prior to muscle contractions‚ however
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Animal Physiology Friday January 13‚ 2012 What are Animals? Invertebrates No spinal column Vertebrates Spinal column Major Animal Phyla Porifera Cnidaria Platyhel-minths Mollusca Annileda Nematoda Arthro-poda Echino-dermata Chordata What is Animal Physiology? What is Physiology? “The study of how animals work” (function) Knut Schmidt-Nielsen (1915–2007) – came up with the whole scheme of animal physiology from cell to whole organism temperature
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second AP can be generated with strong stimulus during this period. The absolute refractory period is seen because the two stimuli are close to each other. Since the sciatic nerve under investigation is a collection of individual neurons‚ it is also graded in its response. The best approach for measuring is to look at the difference between two stimulations of different time intervals. The relative refractory period can be concluded throughout the shortest interval between two impulses (Kopec et al
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