• Study Resource
  • Explore Categories
    • Arts & Humanities
    • Business
    • Engineering & Technology
    • Foreign Language
    • History
    • Math
    • Science
    • Social Science

    Top subcategories

    • Advanced Math
    • Algebra
    • Basic Math
    • Calculus
    • Geometry
    • Linear Algebra
    • Pre-Algebra
    • Pre-Calculus
    • Statistics And Probability
    • Trigonometry
    • other →

    Top subcategories

    • Astronomy
    • Astrophysics
    • Biology
    • Chemistry
    • Earth Science
    • Environmental Science
    • Health Science
    • Physics
    • other →

    Top subcategories

    • Anthropology
    • Law
    • Political Science
    • Psychology
    • Sociology
    • other →

    Top subcategories

    • Accounting
    • Economics
    • Finance
    • Management
    • other →

    Top subcategories

    • Aerospace Engineering
    • Bioengineering
    • Chemical Engineering
    • Civil Engineering
    • Computer Science
    • Electrical Engineering
    • Industrial Engineering
    • Mechanical Engineering
    • Web Design
    • other →

    Top subcategories

    • Architecture
    • Communications
    • English
    • Gender Studies
    • Music
    • Performing Arts
    • Philosophy
    • Religious Studies
    • Writing
    • other →

    Top subcategories

    • Ancient History
    • European History
    • US History
    • World History
    • other →

    Top subcategories

    • Croatian
    • Czech
    • Finnish
    • Greek
    • Hindi
    • Japanese
    • Korean
    • Persian
    • Swedish
    • Turkish
    • other →
 
Profile Documents Logout
Upload
Nerve Cell Signaling - Mr. Moore`s Web Page
Nerve Cell Signaling - Mr. Moore`s Web Page

... How does a nerve work • Watch each of the videos that follow. Use the videos to describe the process of depolarization. Try to do it in a series of steps. You can also use other web sites to help you in this process. You might want to use the picture on slide 9 to help you describe the process. Wri ...
Additional Nervous System Notes
Additional Nervous System Notes

... • Contain rhodopsin – visual pigment made up of protein (opsin) and retinal (made from vitamin A) – Light falling on rhodopsin causes reversible change in shape – called bleaching – This generates an action potential that is carried to visual cortex of brain via optic nerve • Groups of rods may pass ...
CHAPTER 39 NEURONS AND NERVOUS SYSTEMS
CHAPTER 39 NEURONS AND NERVOUS SYSTEMS

... The sodium-potassium (Na+-K+) pump is an active transport system that moves Na+ ions out and K+ ions into the axon. e. The pump is always working because the membrane is permeable to these ions and they tend to diffuse toward the lesser concentration. f. Since the plasma membrane is more permeable ...
7. The Nervous System Identify the major structures and areas of the
7. The Nervous System Identify the major structures and areas of the

... 2) Cones • 3 types: blue, green, red • Allows mediation of colour • High resolution but insensitive to light • Loss of cone function leads to macular degeneration • Fovea centralis contains only cones and provides the sharpest vision • 6 million cones • Protein called photopsins L ...
Q: A.1 Answer (b) neurolemma Q: A.2 Answer (d) Pons
Q: A.1 Answer (b) neurolemma Q: A.2 Answer (d) Pons

... The advantages of having a nervous system are as follows: (a) Keeps us informed about the outside world through sense organs. (b) Enables us to remember, think and reason out. (c) Controls and harmonizes all voluntary muscular activities such as running, holding, writing (d) Regulates involuntary ac ...
Cranial nerves (L15)
Cranial nerves (L15)

... points ...
1 Neurons 2 Electrical activity of neurons at rest.
1 Neurons 2 Electrical activity of neurons at rest.

... Neurons are electrically active. They produce large electrical signals called “action potentials” or “spikes” or “nerve impulses” that can travel down the axon and are reliably transmitted to other neurons. Action potentials are considered to be stereotypical and are the main communication units in ...
Chapter 7 -Nervous System - Austin Community College
Chapter 7 -Nervous System - Austin Community College

... Chapter 8 Lecture Notes ...
SENSORY NERVOUS SYSTEM
SENSORY NERVOUS SYSTEM

... receptors that respond when they first receive a stimulus but stop responding if the strength of the stimulus remains constant. Many of the tactile receptors in the skin belong to this class. Some phasic receptors, most notably the Pacinian corpuscle, respond with a slight depolarization called the ...
Stimulus and response
Stimulus and response

... • E.1.3 Draw and label a diagram of a reflex arc for a pain withdrawal reflex, including the spinal cord and its spinal nerves, the receptor cell, sensory neuron, relay neuron, motor neuron and effector. • E.1.4 Explain how animal responses can be affected by natural selection, using two examples. ...
THE NERVOUS SYSTEM - Tamalpais Union High School District
THE NERVOUS SYSTEM - Tamalpais Union High School District

... • Sending neuron impulses = action potential – change in electrical charge in cell membrane – depends on electrolytes • potassium (K+) and sodium (Na+) ...
The Nervous System
The Nervous System

... E = axon F = Nodes of Ranvier: spaces in sheath, exposing axon G = myelin sheath: is Schwann cell plasma membrane made of myelin(a lipid substance that is an excellent insulator) that covers most long fibers; gives nerve fibers their white glistening appearance; plays a role in nerve regeneration – ...
Central Nervous System
Central Nervous System

... Sodium ions (Na+), calcium ions (Ca2+), and chloride ions (Cl-) are in much greater concentration outside the cell than inside Potassium ions (K+) and negatively charged molecules, such as proteins, are in much greater concentration inside the cell than outside ...
Sensory Organs and Processes, Part II
Sensory Organs and Processes, Part II

... –  Sympathetic and parasympathetic –  Organization of the brain (briefly) ...
Ch 8 Nervous System Test 1. In a neuron, short, branching
Ch 8 Nervous System Test 1. In a neuron, short, branching

... a. The neurons within the brain or spinal cord that modify this reflex have been damaged. b. The neurons within the periphery have been damaged. c. Your cerebral cortex was damaged but has since re-routed your spinal reflexes. d. Your spine had been severed but has since regrown. e. The withdrawal r ...
Ch. 7: The Nervous System
Ch. 7: The Nervous System

... 9. The CNS sends an impulse out through a motor nerve to stimulate sweat glands to secrete. 10. The action potential travels through the motor neuron and can stimulate 2 or more nerves adjoining it (divergence). 11. This can happen over and over so that a large # of sweat glands are contacted and en ...
Sense Organs
Sense Organs

... (3) The pupil also regulates how much light passes into the eye. c. convergence of the eyes. (1) Convergence is the medial rotation of the eyes during close vision. E. Structure and Function of the Retina 1. Retina consists of a pigmented retina and a sensory retina. a. Pigmented retina (retinal pi ...
Principles of Biology ______Lake Tahoe
Principles of Biology ______Lake Tahoe

... substances to brain, to t ightly control environment b. oligodendrites in cns and c. Schwann cells in pns (Fig. 48.8) d. axons that convey signals very rapidly are enclosed along most of their length by a thick insulating material 1. in vertebrates, = myelin sheath - resembles chain of long beads 2. ...
ANATOMICAL ORGANIZATION of the NERVOUS SYSTEM
ANATOMICAL ORGANIZATION of the NERVOUS SYSTEM

... Branches off the cell body that carry information to the cell body. Usually several to many. Relatively short. Often branched. Have receptors for neurotransmitters. Conduct local potentials. ...
The Nervous System crossword
The Nervous System crossword

... before being released into the synaptic cleft. 12. A neurone is a type of nerve cell. 13. The myelin sheath is an insulating layer, surrounding peripheral nerve cells. 14. The part of the brain that deals with planning, language, recognising images and memory is called the cerebral cortex. 16. The s ...
CHAPTER 4
CHAPTER 4

... Impulses (2) • The Resting Potential – It is the membrane potential of a nerve or muscle cell, subject to changes when activated. – K+ gradients maintained by the Na+/K+-ATPase are responsible for resting potential. – Nernst equation used to calculate the voltage equivalent of the concentration grad ...
Answers to Mastering Concepts Questions
Answers to Mastering Concepts Questions

... 1. The parts of the vertebrate eye include the sclera, the choroids, and the retina. The sclera includes the white of the eye and the cornea. The choroid includes blood vessels, lens, iris, and pupil. The retina is a layer of photoreceptors at the back of the eye. Most of the eye’s volume is filled ...
The Nervous System- Nervous Tissue
The Nervous System- Nervous Tissue

... •Most axons of the nervous system are surrounded by a myelin sheath (myelinated axons) of Ranvier ...
The Nervous System
The Nervous System

... ● acetylcholine: can be inhibitory or excitatory, depending on the receptor ● reduces the rate and strength of contraction of cardiac muscle cells ● biogenic amines are derived from amino acids o includes epinephrine and norepinephrine which function as ...
Lecture 13: Insect nerve system (NS)
Lecture 13: Insect nerve system (NS)

... By the direction of information that they send (function) • Afferent (sensory) neurons --bipolar or multipolar cells have dendrites that are associated with sense organs. They carry information TOWARD the central nervous system (CNS). • Efferent (motor) neurons -- unipolar cells that conduct signals ...
< 1 ... 231 232 233 234 235 236 237 238 239 ... 293 >

Rheobase



Rheobase is a measure of membrane excitability. In neuroscience, rheobase is the minimal current amplitude of infinite duration (in a practical sense, about 300 milliseconds) that results in the depolarization threshold of the cell membranes being reached, such as an action potential or the contraction of a muscle. In Greek, the root ""rhe"" translates to current or flow, and ""basi"" means bottom or foundation: thus the rheobase is the minimum current that will produce an action potential or muscle contraction.Rheobase can be best understood in the context of the strength-duration relationship (Fig. 1). The ease with which a membrane can be stimulated depends on two variables: the strength of the stimulus, and the duration for which the stimulus is applied. These variables are inversely related: as the strength of the applied current increases, the time required to stimulate the membrane decreases (and vice versa) to maintain a constant effect. Mathematically, rheobase is equivalent to half the current that needs to be applied for the duration of chronaxie, which is a strength-duration time constant that corresponds to the duration of time that elicits a response when the nerve is stimulated at twice rheobasic strength.The strength-duration curve was first discovered by G. Weiss in 1901, but it was not until 1909 that Louis Lapicque coined the term ""rheobase"". Many studies are being conducted in relation to rheobase values and the dynamic changes throughout maturation and between different nerve fibers. In the past strength-duration curves and rheobase determinations were used to assess nerve injury; today, they play a role in clinical identification of many neurological pathologies, including as Diabetic neuropathy, CIDP, Machado-Joseph Disease, and ALS.
  • studyres.com © 2026
  • DMCA
  • Privacy
  • Terms
  • Report