Nerves and Nerve Impulse

Size: px
Start display at page:

Download "Nerves and Nerve Impulse"

Transcription

1 Nerves and Nerve Impulse Terms Absolute refractory period: Period following stimulation during which no additional action potential can be evoked. Acetylcholine: Chemical transmitter substance released by some nerve endings. Action potential: A large transient depolarization event, including polarity reversal, that is conducted along the membrane of a muscle cell or a nerve fiber. Adrenaline: see Epinephrine Afferent neuron: Nerve cell that carries impulses towards the Central Nervous System (CNS). Autonomic Nervous System: Efferent division of the peripheral nervous system that innovates cardiac and smooth muscles and glands; also called the involuntary or visceral motor system. Axon: Neuron process that carries impulses away from the nerve cell body; efferent process; the conducting portion of a nerve cell. Bipolar neuron: Neuron with axon and dendrite that extend from opposite sides of the cell body. Catecholamines: Neurotransmitters i.e. epinephrine and norepinephrine. Central nervous system: The brain and the spinal cord Cholinergic fibers: Nerve ending that upon stimulation releases Acetylcholine. Conductivity: That ability to transmit an electrical impulse Dendrite: Branching neuron process that serves as a receptive, or input, region; transmits the nerve impulse to the cell body. Depolarization: The loss of a state of polarity; loss of a negative charge inside the cells. Diffusion: The spreading of particles in a gas or solution with a movement towards uniform distribution of particles. Effector: Organ, gland, or muscle capable of being activated by nerve ending. Efferent: Carrying away or away from, especially a nerve fiber that carries impulses away from CNS. Mixed nerves: Nerves containing the processes of motor and sensory neurons; their impulses travel to and from CNS. Motor nerves: Nerves that carry impulses leaving the brain and the spinal cord. Motor unit: A motor neuron and all the muscle cells it stimulates.

2 Multipolar neuron: Neuron that has one long axon and numerous dendrites. Myelin sheath: Fatty insulating sheath that surrounds all but the smallest nerve. Neuralgia: Nonexcitable cells of neural tissue that supports, protects, and insulates the neurons. Neuron: Cell of the nervous system specialized to generate and transmit nerve impulses. Neurotransmitters: Chemical released by nerve that may upon binding to receptors of neurons or Effectors cells, stimulate or inhibit them. Parasympathetic nervous system: The division of the autonomic nervous system that over-sees digestion, elimination, and glandular function; the resting and digestion subdivision. Peripheral nervous system (PNS): Portion of the nervous system consisting of nerves and ganglia that lie outside the brain and spinal cord. Polarized: State of the plasma membrane of an unstimulated neuron or muscle cell in which the inside of the cell is relatively negative in comparison to the outside; the resting state. Receptor: Peripheral nerve ending specialized for response to particular types of stimuli. Relative refractory period: Period following stimulation during which only a stronger than usual stimulus can evoke an action potential. Sensory nerve: Nerve that contains processes of sensory neurons and carries nerve impulse to the CNS. Sensory neuron: Neuron that initiates nerve impulses following receptor stimulation. Sensory receptor: Dendrites and organs, or parts of other cell types, specialized to respond to a stimulus. Sensory transduction: Conversion of stimulus energy into a nerve impulse. Somatic nervous system: Division of the peripheral nervous system that provides the motor innovation of skeletal muscles. Stimulus: An excitant or irritant; a change in the environment that evokes a response. Synapse: Functional junction or point of close contact between two neurons or between a neuron and an Effector cell. Synaptic cleft: Fluid- filled space at a synapse between neurons and muscle. Threshold: Weakest stimulus capable of producing a response in an irritable tissue. Neurons Neurons are also called nerve cells. They are highly specialized cells that conduct messages in the form of nerve impulses. Neurons are the structural unit of the nervous system. Neurons are made up of dendrites, the cell body, axon, and the axon terminals. Some neurons are Myelinated and others are Unmyelinated Myelinated neurons are called white fiber and are found in the white matter of the brain.

3 Unmyelinated neurons are called gray fibers and make up the gray matter. Neurilemma aids in the repair of damaged nerve fibers. Classification of Neurons A. Structural Classification: Neurons are grouped structurally according to the numbers of processes that extend from their cell body. Three major groups: 1. Multipolar neurons - numerous branching dendrites and one axon - most common neuron type in humans - major neuron type in the central nervous system 2. Bipolar neurons - have two processes - an axon and dendrite - that extend from opposite sides of the cell body - rare in the adult body - found in special sense organs, where they act as receptor cells (e.g.) eyes, and nose 3. Unipolar neurons

4 - have single process that emerges from the cell body, which is very short and divides into axon and dendrite. - sometimes called pseudounpolar neurons B. Functional Classification: Neurons are divided according to the direction the nerve impulse is traveling relative to the central nervous system Three major types: 1. Sensory or afferent neurons o most are unpolar neurons, except for the bipolar neurons that are found in the special senses organs o typically heavily Myelinated o function as sensory receptors 2. Motor or efferent neurons o carry impulses away from the central nervous system (CNS) to the effector organs (muscles and glands) of the body o multipolar, except for some neurons of the autonomic nervous system, their cell bodies are in the CNS. 3. Association neurons or interneurons o lie between motor and sensory neurons in the neural pathways, where integration takes place o typically multipolar o confined entirely within the CNS Nerves Endoneurium - sheath of connective tissue that surrounds each nerve fiber. Perineurium - connective tissue that bounds groups of nerve fibers together, to form bundles of fibers called fascicles. Epineurium - Tough fibrous sheath that encloses all the fascicles to form a nerve

5 Neurophysiology Neurons are highly sensitive to stimuli. When a neuron is adequately stimulated, an electrical impulse is conducted along the length of the axon. The response is always the same, regardless of the source or type of stimulus. A.) Basic Principles of Electricity In the body, electrical currents reflect the flow of ions across the cell membrane. Plasma membranes contain a variety of ion channels constructed by membrane proteins. Some of these are passive, or leakage, these channels are always open. Other gates are active, or gated, these channels are characterized by a molecular "gate". There are two types of gated gates: o Chemically-gated channels open when the appropriate neurotransmitters bind to receptors. o Voltage-gated channels open and close in response to changes in the membrane potential, or voltage. When the "gates" open, the ions diffuse across the membrane creating electrical current. Ions move along their chemical gradients when they diffuse passively from an area of higher concentration to an area of lower concentration, and along their electrical gradients when they move towards an area of opposite electrical charge. B.) The Resting Membrane Potential: The Polarized State neurons at rest are said to be polarized, with an excess of negative charge inside the neuron and corresponding positive charge outside. This potential difference at rest is called the Resting Membrane potential

6 at resting state, the cell is impermeable to Na + ions and low permeability to K + ions, and the Na + /K + pump maintain the ionic concentration gradients that lead to the resting membrane potential Sodium (Na + ) are in a higher concentration in the extracelluar fluid (outside) Potassium (K + )are in a higher concentration in the intracelluar fluid (Inside) membrane has low permeability to any charged species of ions, but there are protein channels or gates selective for certain ions embedded within the membrane Na + /K + pump requires energy which it gets from ATP hydrolysis, also known as the Na + /K + ATPase the resting membrane potential is -75 mv to -60 mv these ionic differences are the consequence of an action potential: 1. the differential permeability of the plasma membrane to Na + and K + (the membrane impartiality to Na + ) 2. the operation of the sodium-potassium pump, which actively transports Na + out of the cell and K + into the cell. For every 2 Na + that are pumped out 1K + is pumped in. Therefore the sodium-potassium pump stabilizes the resting membrane potential by maintaining the diffusion gradients for sodium and potassium C). Action Potentials An action potential is a brief, but large, depolarization with a total amplitude (change in voltage) of about 100 mv (from -70 mv to +30 mv) action potential is initiated when the stimulus reaches the threshold level. The threshold level works on the all or none principle. In other words, the stimulus must reach a "certain" voltage in order for a impulse to be generated. Once the threshold level is reached, it will always result in a action potential. depolarizing phase of the action potential is due to the increased permeability of the membrane to Na + due to the Na + gates opening. This causes the Na + to rush into the neuron; hence changing the resting membrane potential from -70 mv to +30 mv. repolarizing phase of the action potential: the membrane permeability to Na + decreases and K + increases as the Na + gates close and the K + gates open. The

7 sodium- potassium (Na + /K + ) pump, also known as the ATPase, becomes active to restore the resting membrane potential. The Na + /K + pump gets its energy from ATP hydrolysis. initial depolarization of the membrane is caused by the opening of the voltage sensitive Na + channels. A current then moves across the membrane carried by Na + ions. action potential moves down the axon in a unidirectional fashion, because as it moves forward the refectory period begins behind it. Action potential propagation in a Myelinated axon myelin sheath covers the axon and acts as an insulator, which reduces the leakage of K + ions in advance of the inward Na + currents which would otherwise occur during the depolarization phase of the action potential so that the depolarization can spread further away along the axon. the myelin sheath is interrupted by Nodes of Ranvier, where the depolarization occurs the nerves with myelin sheath have faster conducting nerve fibers, due to the nerve impulse traveling from node to node Resting Membrane Potential higher concentration of Na + on the outside of the neuron membrane, and higher concentration of K + in the inside of the neuron Na + gates are closed the Na + - K + pump active Depolarization / Action Potential

8 Events occurring during action potential / depolarization 1. Increase membrane permeability to Na + due to the opening of the Na+ gates 2. Diffusion of Na + to the inside and the K + to the outside of the neuron, thereby reversing the charge of the inside from negative to positive. Repolarization The Synapse each neuron is a separate unit, there is no anatomic connection between neurons or their effector the space between the axon terminal of one neuron and the dendrites or an effector is called a synapse the space between an axon terminal and a muscle is called neuromuscular junction in transmitting the action potential to the next neuron or to the effector, the axon terminal releases neurotransmitters into the synapse. These neurotransmitters diffuse across the synapse to their receptor sites located on the dendrites of the postneuron or the effector (receptor sites are specific to certain neurotransmitters) once enough of the receptor sites are "filled" they initiate an action potential in the post synapic neuron. The remaining of the neurotransmitter is metabolized by a specific enzyme. examples of neurotransmitters: epinephrine / adrenaline norepinephrine/ noradreadin

9 1. Label the following diagram. Review Questions

10 2. carries impulses away from the cell body. 3. carries impulses towards the cell body. 4. The space between the axon terminal and the dendrites of the cell body of the next neuron is called the. 5. State the function of the myelin sheath. 6. At synapses, the nerve impulse is carried by a that is released by the synaptic knobs on the of a neuron. 7. When a neuron is not carrying an impulse, its cell membrane has a charge on the outside and a charge on the inside of the membrane. 8. Depolarization is brought about by a stimulus which makes the neuron membrane very permeable to ions, which rush the cell. As a result, the membrane now has a charge outside and charge inside the neuron. 9. Explain in a point form the events that occur during each of the following stages of nerve impulse: (on a separate sheet of paper) a. depolarization b. repolarization c. resting membrane potential

11 10. are called white fibers which make up the. Unmyelinated neurons appear and make up the. 11. In order for an action potential to be initiated the must be reached. 12. Myelinated neurons are faster/slower than Unmyelinated neurons. 13. Explain why the action potential moves only in one direction.

Ch. 7 Neurons: The Matter of the Mind

Ch. 7 Neurons: The Matter of the Mind Ch. 7 Neurons: The Matter of the Mind The nervous system: Controls, integrates and coordinates the body s activities Provides rapid and brief responses to stimuli Has 2 major divisions: 1. The central

More information

Association neurons allow for integration of information, reflexes and associative functions (decision making)

Association neurons allow for integration of information, reflexes and associative functions (decision making) The Nervous System Nervous system links sensory receptors and motor effectors Sensory (afferent) neurons carry impulses from receptors Motor (efferent) neurons carry impulses to effectors - muscles and

More information

Biology Slide 1 of 38

Biology Slide 1 of 38 Biology 1 of 38 2 of 38 35-2 The Nervous System What are the functions of the nervous system? 3 of 38 35-2 The Nervous System 1. Nervous system: a. controls and coordinates functions throughout the body

More information

HUMAN ANATOMY & PHYSIOLOGY

HUMAN ANATOMY & PHYSIOLOGY C H A P T E R 1 11 HUMAN ANATOMY & PHYSIOLOGY THE HUMAN BODY: AN ORIENTATION FUNDAMENTALS OF THE NERVOUS SYSTEM & NERVOUS TISSUE C H A P T E R 1 PART I HUMAN ANATOMY & PHYSIOLOGY FUNDAMENTALS OF THE NERVOUS

More information

12. Nervous System: Nervous Tissue

12. Nervous System: Nervous Tissue 12. Nervous System: Nervous Tissue I. Introduction to the Nervous System General functions of the nervous system The nervous system has three basic functions: 1. Gather sensory input from the environment

More information

Nerve Cell Flashcards

Nerve Cell Flashcards 1. What does the word innervates mean? Refers to a nerve supplying a muscle or organ. For example, The phrenic nerve innervates the diaphragm muscle. 2. 3 parts of the Nervous System 1. Central Nervous

More information

Anatomy & Physiology Neural Tissue Worksheet

Anatomy & Physiology Neural Tissue Worksheet Anatomy & Physiology Neural Tissue Worksheet 1. Name the two major subdivisions of the nervous system Nervous System Nervous System 2. Name the two parts (organs) of the CNS 3. What are the three functions

More information

Nerve Cell Physiology

Nerve Cell Physiology Nerve Cell Physiology body is electrically neutral there are small differences in electrical charge between inside and outside of cell membranes due to differences in + and ions on inside and outside of

More information

Essay Question for exam 3

Essay Question for exam 3 Essay Question for exam 3 Describe how action potentials are generated and propagated along neurons. Include in your description how intracellular voltage changes during the action potential by labeling

More information

11 Fundamentals of the Nervous System and Nervous Tissue: Part A

11 Fundamentals of the Nervous System and Nervous Tissue: Part A 11 Fundamentals of the Nervous System and Nervous Tissue: Part A Functions of the Nervous System 1.Sensory input Information gathered by sensory receptors about internal and external changes 2.Integration

More information

Chapter 7: The Nervous System

Chapter 7: The Nervous System Chapter 7: The Nervous System Objectives Discuss the general organization of the nervous system Describe the structure & function of a nerve Draw and label the pathways involved in a withdraw reflex Define

More information

AP Biology I. Nervous System Notes

AP Biology I. Nervous System Notes AP Biology I. Nervous System Notes 1. General information: passage of information occurs in two ways: Nerves - process and send information fast (eg. stepping on a tack) Hormones - process and send information

More information

Neurons, Synapses, and Signaling

Neurons, Synapses, and Signaling Chapter 8 Neurons, Synapses, and Signaling Overview: Lines of Communication The cone snail kills prey with venom that disables neurons Neurons are nerve cells that transfer information within the body

More information

Nervous Systems: Neuron Structure and Function

Nervous Systems: Neuron Structure and Function Nervous Systems: Neuron Structure and Function Integration An animal needs to function like a coherent organism, not like a loose collection of cells. Integration = refers to processes such as summation

More information

ANATOMY & PHYSIOLOGY. Part 1: The Nervous System

ANATOMY & PHYSIOLOGY. Part 1: The Nervous System ANATOMY & PHYSIOLOGY Part 1: The Nervous System Please watch the following video. - Click the link below. - Adjust volume on speaker (far right on teacher desk). - Increase picture size by clicking bottom

More information

11.1: The Role of the Nervous System pg

11.1: The Role of the Nervous System pg UNIT 4: Homeostasis Chapter 11: The Nervous System pg. 514 11.1: The Role of the Nervous System pg 516-521 Organisms need to senses heir environments to make appropriate adjustments and survive. The nervous

More information

Major Structures of the Nervous System

Major Structures of the Nervous System Major Structures of the Nervous System Brain, cranial nerves, spinal cord, spinal nerves, ganglia, enteric plexuses and sensory receptors Tortora & Grabowski 9/e ã2000 JWS 12-1 Nervous System Divisions

More information

2. Regulator responses - controlling responses and directing them to the right place

2. Regulator responses - controlling responses and directing them to the right place Nervous Regulation A. Functions of the nervous system Maintain Regulator responses - controlling responses and directing them to the right place 3. Coordinate responses - B. Mechanisms for Nervous Regulation

More information

Figure: 11.2 ;pg 387 4

Figure: 11.2 ;pg 387 4 ANATOMY I; CHAPTER 11, NERVOUS SYSTEM Nervous system is the master control, 2 communication and coordinating system between the different body structures and systems Every activity, thought and emotion

More information

The Nervous System CH 28

The Nervous System CH 28 The Nervous System CH 28 Nervous system Structure and function Nerve signals and their transmission Nervous systems The human brain Giant Squid! Artituthus can be 30 ft+ The Giant Squid Nervous System

More information

Nervous system. Figure 1 The nervous system.

Nervous system. Figure 1 The nervous system. Nervous system Components The nervous system is the central nervous system (CNS) - the brain and spinal cord, and the peripheral nervous system (PNS) - nerves connecting to the CNS and serving the body.

More information

Histology of Nervous Tissue Nervous system consists mostly of nervous tissue, which is highly cellular. Less than 20% of the CNS is extracellular

Histology of Nervous Tissue Nervous system consists mostly of nervous tissue, which is highly cellular. Less than 20% of the CNS is extracellular The Nervous System Overview The nervous system is the master controlling and communicating system of the body. Every thought, action and emotion reflects its activity. Its cells communicate by electrical

More information

Resting membrane potential ~ -70mV - Membrane is polarized

Resting membrane potential ~ -70mV - Membrane is polarized Resting membrane potential ~ -70mV - Membrane is polarized (ie) Electrical charge on the outside of the membrane is positive while the electrical charge on the inside of the membrane is negative Changes

More information

Student Academic Learning Services Page 1 of 8 Nervous System Quiz

Student Academic Learning Services Page 1 of 8 Nervous System Quiz Student Academic Learning Services Page 1 of 8 Nervous System Quiz 1. The term central nervous system refers to the: A) autonomic and peripheral nervous systems B) brain, spinal cord, and cranial nerves

More information

Ion Channels. Graphics are used with permission of: Pearson Education Inc., publishing as Benjamin Cummings (http://www.aw-bc.com)

Ion Channels. Graphics are used with permission of: Pearson Education Inc., publishing as Benjamin Cummings (http://www.aw-bc.com) Ion Channels Graphics are used with permission of: Pearson Education Inc., publishing as Benjamin Cummings (http://www.aw-bc.com) ** There are a number of ion channels introducted in this topic which you

More information

FUNCTIONS OF THE NERVOUS SYSTEM 1. Sensory input. Sensory receptors detects external and internal stimuli.

FUNCTIONS OF THE NERVOUS SYSTEM 1. Sensory input. Sensory receptors detects external and internal stimuli. FUNCTIONS OF THE NERVOUS SYSTEM 1. Sensory input. Sensory receptors detects external and internal stimuli. 2. Integration. The brain and spinal cord process sensory input and produce responses. 3. Homeostasis.

More information

The Nervous System : communication

The Nervous System : communication The Nervous System : communication A. Neurons = masses of nerve cells that transmit information 1. Cell Body - contains the nucleus and two extensions 2. Dendrites shorter, more numerous, receive information

More information

Medfamily team Medfamily team 1) The resting membrane potential: a. Is much closer to the equilibrium for Na+ than to the equilibrium potential for

Medfamily team Medfamily team 1) The resting membrane potential: a. Is much closer to the equilibrium for Na+ than to the equilibrium potential for 1) The resting membrane potential: a. Is much closer to the equilibrium for Na+ than to the equilibrium potential for K+. b. Is much closer to the equilibrium for K+ than to the equilibrium potential for

More information

Anatomy & Physiology Bio 2401 Lecture. Instructor: Daryl Beatty Nervous System Introduction Part 1

Anatomy & Physiology Bio 2401 Lecture. Instructor: Daryl Beatty Nervous System Introduction Part 1 Anatomy & Physiology Bio 2401 Lecture Instructor: Daryl Beatty Nervous System Introduction Part 1 Nervous System Introduction Chapter 11 Section A Sequence 4.1 DB Nervous system 1 Intro Presentations 4.2,

More information

Chapter 11: Functional Organization of Nervous Tissue

Chapter 11: Functional Organization of Nervous Tissue Chapter 11: Functional Organization of Nervous Tissue Multiple Choice 1. The nervous system A) monitors internal and external stimuli. B) transmits information in the form of action potentials. C) interprets

More information

Chapter 9 Nervous System

Chapter 9 Nervous System Chapter 9 Nervous System Nervous System function: The nervous system is composed of neurons and neuroglia. at the ends of peripheral nerves gather information and convert it into nerve impulses. When sensory

More information

PART I: Neurons and the Nerve Impulse

PART I: Neurons and the Nerve Impulse PART I: Neurons and the Nerve Impulse Identify each of the labeled structures of the neuron below. A. B. C. D. E. F. G. Identify each of the labeled structures of the neuron below. A. dendrites B. nucleus

More information

NEUROSCIENCE EXAM 1 FALL 2011 KEY

NEUROSCIENCE EXAM 1 FALL 2011 KEY NEUROSCIENCE EXAM 1 FALL 2011 KEY Multiple Choice: Read the entire question and all answers before choosing (circle the letter ) the one best answer. Each question is worth 2 point 1. Which of the following

More information

Name: Teacher: Olsen Hour:

Name: Teacher: Olsen Hour: Name: Teacher: Olsen Hour: The Nervous System: Part 1 Textbook p216-225 41 In all exercises, quizzes and tests in this class, always answer in your own words. That is the only way that you can show that

More information

Nervous System Section 35 1 Human Body Systems (pages )

Nervous System Section 35 1 Human Body Systems (pages ) Name Period Chap 35.1, 35.2, 35.3, 36.1, 36.2, 36.3, and 38.3 A look at cells, tissues, organs, organ systems of humans as well as the role of passive and active transport in nerve and muscle conduction

More information

Neuron cell structure Dendrites: Soma: Axon hillock: Axon: Myelin sheath: Nodes of Ranvier: Axon terminal / Terminal buttons:

Neuron cell structure Dendrites: Soma: Axon hillock: Axon: Myelin sheath: Nodes of Ranvier: Axon terminal / Terminal buttons: Neuron cell structure s: Contain neuroreceptors that respond when exposed to neurotransmitters. : Body of neuron cell. DNA in the nucleus in the soma code for all the proteins of the neuron. Axon hillock:

More information

48a A&P: Nervous System -! Introduction, Physiology, and Cells

48a A&P: Nervous System -! Introduction, Physiology, and Cells 48a A&P: Nervous System -! Introduction, Physiology, and Cells 48a A&P: Nervous System -! Introduction, Physiology, and Cells! Class Outline" 5 minutes" "Attendance, Breath of Arrival, and Reminders "

More information

Neuron Structure and Function

Neuron Structure and Function C H A P T E R 4 Neuron Structure and Function PowerPoint Lecture Slides prepared by Stephen Gehnrich, Salisbury University Neurons Vary in structure and properties Use same basic mechanisms to send signals

More information

Chapter 17 Nervous Tissue

Chapter 17 Nervous Tissue Chapter 17 Nervous Tissue Introduction The nervous system and the endocrine system are the body s major control and integrating centers. Neurology is the study of the normal functioning and disorders of

More information

IV. Anatomy of a Neuron aka. A nerve cell: * various sizes; from < 1mm to 1 meter in length * various nerve impulse speeds; from 0.

IV. Anatomy of a Neuron aka. A nerve cell: * various sizes; from < 1mm to 1 meter in length * various nerve impulse speeds; from 0. IV. Anatomy of a Neuron aka. A nerve cell: * various sizes; from < 1mm to 1 meter in length * various nerve impulse speeds; from 0.5 to 395 meters/sec [1to280 miles/hour] How do Neurons communicate? Neurons

More information

Biopsychology Chapter 2: Structure and Functions of Cells of the Nervous System. Neuron Structure. Neuron Classification Schemes

Biopsychology Chapter 2: Structure and Functions of Cells of the Nervous System. Neuron Structure. Neuron Classification Schemes Biopsychology Chapter 2: Structure and Functions of Cells of the Nervous System Neuron Structure 2.2 Neuron Classification Schemes Neurons can be classified according to Number of axon processes: Unipolar:

More information

CHAPTER 10: NERVOUS SYSTEM I. 1. Name the two major divisions of the nervous system and list the organs within each.

CHAPTER 10: NERVOUS SYSTEM I. 1. Name the two major divisions of the nervous system and list the organs within each. OBJECTIVES: 1. Name the two major divisions of the nervous system and list the organs within each. 2. Fully discuss the three general functions of the nervous system, and draw a figure that summarizes

More information

Activity 5: The Action Potential: Measuring Its Absolute and Relative Refractory Periods. 250 20 Yes. 125 20 Yes. 60 20 No. 60 25 No.

Activity 5: The Action Potential: Measuring Its Absolute and Relative Refractory Periods. 250 20 Yes. 125 20 Yes. 60 20 No. 60 25 No. 3: Neurophysiology of Nerve Impulses (Part 2) Activity 5: The Action Potential: Measuring Its Absolute and Relative Refractory Periods Interval between stimuli Stimulus voltage (mv) Second action potential?

More information

Neurophysiology. 2.1 Equilibrium Potential

Neurophysiology. 2.1 Equilibrium Potential 2 Neurophysiology 2.1 Equilibrium Potential An understanding of the concepts of electrical and chemical forces that act on ions, electrochemical equilibrium, and equilibrium potential is a powerful tool

More information

The Action Potential Graphics are used with permission of: adam.com (http://www.adam.com/) Benjamin Cummings Publishing Co (http://www.awl.

The Action Potential Graphics are used with permission of: adam.com (http://www.adam.com/) Benjamin Cummings Publishing Co (http://www.awl. The Action Potential Graphics are used with permission of: adam.com (http://www.adam.com/) Benjamin Cummings Publishing Co (http://www.awl.com/bc) ** If this is not printed in color, it is suggested you

More information

REVIEW SHEET EXERCISE 3 Neurophysiology of Nerve Impulses Name Lab Time/Date. The Resting Membrane Potential

REVIEW SHEET EXERCISE 3 Neurophysiology of Nerve Impulses Name Lab Time/Date. The Resting Membrane Potential REVIEW SHEET EXERCISE 3 Neurophysiology of Nerve Impulses Name Lab Time/Date ACTIVITY 1 The Resting Membrane Potential 1. Explain why increasing extracellular K + reduces the net diffusion of K + out of

More information

Bi 360: Midterm Review

Bi 360: Midterm Review Bi 360: Midterm Review Basic Neurobiology 1) Many axons are surrounded by a fatty insulating sheath called myelin, which is interrupted at regular intervals at the Nodes of Ranvier, where the action potential

More information

The vocabulary of nerve cells and the senses. Resting and action potentials: the transduction and coding of stimuli

The vocabulary of nerve cells and the senses. Resting and action potentials: the transduction and coding of stimuli The vocabulary of nerve cells and the senses Resting and action potentials: the transduction and coding of stimuli The Bottom Line For any external or internal signal to be recognized by the brain it must

More information

Nervous Tissue Dr. Archana Rani Associate Professor Department of Anatomy KGMU UP, Lucknow

Nervous Tissue Dr. Archana Rani Associate Professor Department of Anatomy KGMU UP, Lucknow 13.01.2015 Nervous Tissue Dr. Archana Rani Associate Professor Department of Anatomy KGMU UP, Lucknow Introduction Property of irritability and conductivity Respond to various types of stimuli Distributed

More information

NERVOUS SYSTEM IN HUMAN BEINGS

NERVOUS SYSTEM IN HUMAN BEINGS Class X Episode 4 A P State NERVOUS SYSTEM IN HUMAN BEINGS You all must have seen a Computer and most of you also use the computer. What are the parts in a computer? The C P U Monitor, Keyboard, and the

More information

Structural Classification of the Nervous System

Structural Classification of the Nervous System Structural Classification of the Nervous System Central nervous system (CNS) Brain and spinal cord Activates nerve responses Interprets sensations Peripheral nervous system (PNS) Composed of all the nerves

More information

Nerve tissue. Development and function of the nervous system Neuron Membrane potentials Synaptic communication

Nerve tissue. Development and function of the nervous system Neuron Membrane potentials Synaptic communication Nerve tissue Development and function of the nervous system Neuron Membrane potentials Synaptic communication Development neuroectoderm neural plate neural tube: brain vesicles spinal cord neural crest

More information

EXCITABILITY & ACTION POTENTIALS page 1

EXCITABILITY & ACTION POTENTIALS page 1 page 1 INTRODUCTION A. Excitable Tissue: able to generate Action Potentials (APs) (e.g. neurons, muscle cells) B. Neurons (nerve cells) a. components 1) soma (cell body): metabolic center (vital, always

More information

Nervous System Histology

Nervous System Histology Nervous System Histology Week 9 Expanded Studies OBJECTIVES Identify the portions of a multipolar neuron using models & slides Differentiate between pseudounipolar, bipolar & multipolar neurons from slides

More information

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Chapter 2 The Neural Impulse Name Period Date MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) The cell body is enclosed by the. A) cell membrane

More information

Chapter 11 Nervous Tissue and Membrane Potentials

Chapter 11 Nervous Tissue and Membrane Potentials Chapter 11 Nervous Tissue and Membrane Potentials There are two types of nervous tissue cells o Neuroglia (glia or glial cells) support the functioning of neurons. o Neurons (nerve cells) transmit electrical

More information

Chapter 15. The Autonomic Nervous. The Autonomic Nervous System. Autonomic Motor Pathways. ANS vs. SNS

Chapter 15. The Autonomic Nervous. The Autonomic Nervous System. Autonomic Motor Pathways. ANS vs. SNS The Autonomic Nervous System Chapter 15 The subconscious involuntary nervous system Regulates activity of smooth muscle, cardiac muscle & certain glands The Autonomic Nervous System 1 2 ANS vs. SNS Somatic

More information

U N IT 10 NE RVOUS SYS TE M REVIEW 1. Which of the following is controlled by the somatic nervous system? A. rate of heartbeat B.

U N IT 10 NE RVOUS SYS TE M REVIEW 1. Which of the following is controlled by the somatic nervous system? A. rate of heartbeat B. U N IT 10 NE RVOUS SYS TE M REVIEW 1. Which of the following is controlled by the somatic nervous system? A. rate of heartbeat B. contraction of skeletal muscles C. increased blood flow to muscle tissue

More information

Functions of the Nervous System

Functions of the Nervous System NAME PERIOD MY TEST DATE: STUDY GUIDE UNIT 9 The Human Body NERVOUS SYSTEM TEST FORMAT: 10 Fill-Ins (using word bank) 20 Multiple choice DIAGRAMS: Neuron Brain DIAGRAMS + OPEN RESPONSE: Label the diagram

More information

NERVOUS SYSTEM. Academic Resource Center

NERVOUS SYSTEM. Academic Resource Center NERVOUS SYSTEM Academic Resource Center Overview of the Nervous System Peripheral nervous system-pns cranial nerves spinal nerves ganglia peripheral nerves enteric plexuses sensory receptors Overview of

More information

Topic 1: Introduction to the Nervous System

Topic 1: Introduction to the Nervous System Topic 1: Introduction to the Nervous System v Name the parts of a generalised neuron & indicate the input, output and integration areas of the neuron. Ø Neurons are the functional cell of the nervous system

More information

Vocab Term Definition of Term Example An individual nerve cell. Carries and processes information.

Vocab Term Definition of Term Example An individual nerve cell. Carries and processes information. Chapter and Topic of this Review Guide: Chapter 2 the Brain pages 52-62 and the Psychology in Action Vocab Term Definition of Term Example Neuron An individual nerve cell. Carries and processes information.

More information

Nerves and Conduction of Nerve Impulses

Nerves and Conduction of Nerve Impulses A. Introduction 1. Innovation in Cnidaria - Nerve net a. We need to talk more about nerves b. Cnidaria have simple nerve net - 2 way conduction c. Basis for more complex system in Vertebrates B. Vertebrate

More information

UNIT 7 NOTES. STIMULI ê RECEPTOR CELL SENSORY NEURON INTERNEURON (CNS)

UNIT 7 NOTES. STIMULI ê RECEPTOR CELL SENSORY NEURON INTERNEURON (CNS) UNIT 7 NOTES NERVOUS SYSTEM Nervous System (NS) has 3 functions: 1. Sensory Input Conduction of electrical signals from sensory receptors 2. Integration Information is interpreted and response generated

More information

Chapter 9. The Nervous System. Mosby items and derived items 2010, 2006, 2002, 1997, 1992 by Mosby, Inc., an affiliate of Elsevier Inc.

Chapter 9. The Nervous System. Mosby items and derived items 2010, 2006, 2002, 1997, 1992 by Mosby, Inc., an affiliate of Elsevier Inc. Chapter 9 The Nervous System Objectives List the organs and divisions of the nervous system and describe the generalized functions of the system as a whole Identify the major types of cells in the nervous

More information

Passive electrotonic conduction decays with distance 1. Cytoplasm resistance 2. Plasma membrane resistance 3. Charges leaks out

Passive electrotonic conduction decays with distance 1. Cytoplasm resistance 2. Plasma membrane resistance 3. Charges leaks out Graded Potentials Passive electrotonic conduction decays with distance 1. Cytoplasm resistance 2. Plasma membrane resistance 3. Charges leaks out Length constant ( ) is defined as the distance over which

More information

Name Date Hour. Nerve Histology Microscope Lab

Name Date Hour. Nerve Histology Microscope Lab Name Date Hour Nerve Histology Microscope Lab PRE-LAB: Answer the following questions using your reading and class notes before starting the microscope lab. 1. What is the difference between the functions

More information

Nervous System. Brain Teaser. IntroducGon. Which number comes next in the sequence? 4,7,10 or 12? Dr. Dinithi Peiris Dept.

Nervous System. Brain Teaser. IntroducGon. Which number comes next in the sequence? 4,7,10 or 12? Dr. Dinithi Peiris Dept. Nervous System Dr. Dinithi Peiris Dept. of Zoology 8 15 14 9 1 6 3 Brain Teaser Which number comes next in the sequence? 4,7,10 or 12? 3 IntroducGon For survival, animal must respond to the outside environment

More information

The connection between adjacent neurons.

The connection between adjacent neurons. 1. The diagram below is of a nerve cell or neuron. i. Add the following labels to the diagram. Axon; Myelin sheath; Cell body; Dendrites; Muscle fibres; ii. Now indicate the direction that the nerve impulse

More information

Nerves mp3

Nerves mp3 Nerves mp3 http://www.cptproton.com/ Test Muscles of the Forearm: Anterior Compartment These muscles are primarily flexors of the wrist and fingers Palmar aponeurosis Flexor retinaculum Flexor digitorum

More information

Origin of Electrical Membrane Potential

Origin of Electrical Membrane Potential Origin of Electrical Membrane Potential parti This book is about the physiological characteristics of nerve and muscle cells. As we shall see, the ability of these cells to generate and conduct electricity

More information

Chapter 15 Anatomy and Physiology Lecture

Chapter 15 Anatomy and Physiology Lecture 1 THE AUTONOMIC NERVOUS SYSTEM Chapter 15 Anatomy and Physiology Lecture 2 THE AUTONOMIC NERVOUS SYSTEM Autonomic Nervous System (ANS) regulates the activity of smooth muscles, cardiac muscles, and certain

More information

Neuron Function. How does a signal travel across and between neurons?

Neuron Function. How does a signal travel across and between neurons? Why? Neuron Function How does a signal travel across and between neurons? Just as the coaxial cables that run down your street or through your house carry television and Internet signals, the job of a

More information

Electrical Properties of Biological Systems

Electrical Properties of Biological Systems Laboratory 3 Electrical Properties of Biological Systems All cells are capable of maintaining a charge separation, or POTENTIAL DIFFERENCE, across their membranes. This is due to the diffusion of sodium

More information

Physiologic Anatomy of Neuron

Physiologic Anatomy of Neuron Physiologic Anatomy of Neuron Basic parts of neuron (nerve cell) Cell body Dendrites Axon Axon hillock Axon terminals Action potentials are initiated at the axon hillock, and conducted throughout a nerve

More information

The Autonomic Nervous System (ANS)

The Autonomic Nervous System (ANS) *Definition: The Autonomic Nervous System (ANS) The autonomic system is the part of the peripheral nervous system that is responsible for regulating involuntary body functions. *Organization of the Nervous

More information

Lecture 13: Insect nerve system (NS)

Lecture 13: Insect nerve system (NS) Lecture 13: Insect nerve system (NS) Brain Thoracic ganglia Abdominal ganglia Subesophageal ganglion Ventral nerve cord Signal transducer, transmitter, processor (integrator) Overview Structures (Anatomy)

More information

How is the Nervous System Organized? Class Objectives: What is the Nervous System? The Biology of the Mind Module 3: Neural and Hormonal Systems

How is the Nervous System Organized? Class Objectives: What is the Nervous System? The Biology of the Mind Module 3: Neural and Hormonal Systems How is the Nervous System Organized? The Biology of the Mind Module 3: Neural and Hormonal Systems 1 Class Objectives: Understand the function and purpose of the nervous system Identify and define the

More information

NERVOUS SYSTEM B 1. Which of the following is controlled by the somatic nervous system? A. rate of heartbeat B. contraction of skeletal muscles C.

NERVOUS SYSTEM B 1. Which of the following is controlled by the somatic nervous system? A. rate of heartbeat B. contraction of skeletal muscles C. NERVOUS SYSTEM B 1. Which of the following is controlled by the somatic nervous system? A. rate of heartbeat B. contraction of skeletal muscles C. increased blood flow to muscle tissue D. movement of food

More information

Nervous Tissue (NT) NEURON

Nervous Tissue (NT) NEURON Nervous Tissue (NT) - highly specialized tissue - forms, receives and sorts signals (irritability) - transmits electrical impulses (conductivity) Functions of Nerve Tissue Nervous tissue allows an organism

More information

Lab #6: Neurophysiology Simulation

Lab #6: Neurophysiology Simulation Lab #6: Neurophysiology Simulation Background Neurons (Fig 6.1) are cells in the nervous system that are used conduct signals at high speed from one part of the body to another. This enables rapid, precise

More information

1. Identify the functions of the nervous system and relate nervous system function to homeostasis and to other organ system previously studied.

1. Identify the functions of the nervous system and relate nervous system function to homeostasis and to other organ system previously studied. Nervous System - Chapter 41 1. Identify the functions of the nervous system and relate nervous system function to homeostasis and to other organ system previously studied. 2. Distinguish between the central

More information

NEURAL CONTROL AND COORDINATION

NEURAL CONTROL AND COORDINATION NEURAL CONTROL AND COORDINATION THE HUMAN NERVOUS SYSTEM VIKASANA - VIGNANA PATHADEDEGE NIMMA NADIGE Bridge Course Program for SSLC Students who want to take up Science in I PUC in 2012 CONTENTS Introduction

More information

Tibor G. Szántó Medical and Health Science Center, University of Debrecen Department of Biophysics and Cell Biology

Tibor G. Szántó Medical and Health Science Center, University of Debrecen Department of Biophysics and Cell Biology Resting potential, action potential and electrical excitibility. Measurement of membrane potential. Tibor G. Szántó Medical and Health Science Center, University of Debrecen Department of Biophysics and

More information

Localization of Certain Neurons Neurotransmitters Nerve Conduction. by: Mary V. Andrianopoulos, Ph.D

Localization of Certain Neurons Neurotransmitters Nerve Conduction. by: Mary V. Andrianopoulos, Ph.D Localization of Certain Neurons Neurotransmitters Nerve Conduction by: Mary V. Andrianopoulos, Ph.D Clarification: Types of Neuron There may be none, one, or many dendrites composing part of a neuron.

More information

Involuntary muscle, ie., not under voluntary control Not striated under microscope Not multinucleated. IE 665Applied Industrial Ergonomics

Involuntary muscle, ie., not under voluntary control Not striated under microscope Not multinucleated. IE 665Applied Industrial Ergonomics IE 665Applied Industrial Ergonomics Suggested external links: http://people.eku.edu/ritchisong/301notes3.htm http://www.youtube.com/watch?v=0_ihc26yxn4&nr=1 Three types of muscle tissues: Skeletal, Smooth

More information

Human Movement Systems: Nervous System

Human Movement Systems: Nervous System Human Movement Systems: Nervous System Objectives After this presentation, the participant will be able to explain: The Human Movement System Nervous System Organization Sensory, integrative and motor

More information

4-Nervous system I: Structure and organization

4-Nervous system I: Structure and organization 4-Nervous system I: Structure and organization GENERAL ORGANIZATION NEURON STRUCTURE BRAIN & CRANIAL NERVES SPINAL CORD & NERVES AUTONOMIC SYSTEM Announcements Andrew s Office Hours: Friday 9:00-10:00,

More information

Please read chapter 15, The Autonomic Nervous System, complete this study guide, and study this material BEFORE coming to the first class.

Please read chapter 15, The Autonomic Nervous System, complete this study guide, and study this material BEFORE coming to the first class. Please read chapter 15,, complete this study guide, and study this material BEFORE coming to the first class. I. Introduction to the autonomic nervous system: Briefly describe the autonomic nervous system.

More information

Chapter 7: The Nervous System

Chapter 7: The Nervous System Chapter 7: The Nervous System I. Organization of the Nervous System Objectives: List the general functions of the nervous system Explain the structural and functional classifications of the nervous system

More information

Parts of the Nerve Cell and Their Functions

Parts of the Nerve Cell and Their Functions Parts of the Nerve Cell and Their Functions Silvia Helena Cardoso, PhD [ 1. Cell body] [2. Neuronal membrane] [3. Dendrites] [4. Axon] [5. Nerve ending] 1. Cell body The cell body (soma) is the factory

More information

Neural Communication by Richard H. Hall, 1998

Neural Communication by Richard H. Hall, 1998 Neural Communication by Richard H. Hall, 1998 Forces and Membranes Now that we've considered the structure of the cells of the nervous system it is important to address their principal function, communication.

More information

AUTONOMIC NERVOUS SYSTEM. c. CNS (central nervous system) control: voluntary (but has involuntary components; e.g. reflexes)

AUTONOMIC NERVOUS SYSTEM. c. CNS (central nervous system) control: voluntary (but has involuntary components; e.g. reflexes) page 1 INTRODUCTION A. Divisions of the Peripheral Nervous System 1. Somatic nervous system (voluntary) a. tissues innervated: skeletal muscle b. action: always excitatory (cause muscle contraction) c.

More information

AUTONOMIC NERVOUS SYSTEM

AUTONOMIC NERVOUS SYSTEM AUTONOMIC NERVOUS SYSTEM Somatic efferent and ANS Somatic Efferent Control is over skeletal muscles. External environment This division of the PNS responds to some change in the external environment. single

More information

Active Transport Moves solute Against Their Electrochemical Gradient

Active Transport Moves solute Against Their Electrochemical Gradient Active Transport Moves solute Against Their Electrochemical Gradient Active transport of solutes against their electrochemical gradient is essential to maintain the intracellular ionic composition of cells

More information

The Anatomy and Physiology of Animals/Nervous System Worksheet/Worksheet Answers

The Anatomy and Physiology of Animals/Nervous System Worksheet/Worksheet Answers The Anatomy and Physiology of Animals/Nervous System Worksheet/Worksheet Answers From WikiEducator < The Anatomy and Physiology of Animals Nervous System Worksheet 1. The diagram below is of a nerve cell

More information

Nervous Tissue Chapter 12

Nervous Tissue Chapter 12 Nervous Tissue Chapter 12 Overview of the Nervous System Cells of the Nervous System Electrophysiology of Neurons Synapses Subdivisions of the Nervous System Two major anatomical subdivisions: Central

More information

Nervous System Function:

Nervous System Function: Nervous System Function: It regulates and coordinates many of the other systems. It controls memory and logical thought, and it gives the body the ability to react or respond to both internal and external

More information

Autonomic Nervous System Dr. Ali Ebneshahidi

Autonomic Nervous System Dr. Ali Ebneshahidi Autonomic Nervous System Dr. Ali Ebneshahidi Nervous System Divisions of the nervous system The human nervous system consists of the central nervous System (CNS) and the Peripheral Nervous System (PNS).

More information

Anatomy Review. Graphics are used with permission of: Pearson Education Inc., publishing as Benjamin Cummings (http://www.aw-bc.

Anatomy Review. Graphics are used with permission of: Pearson Education Inc., publishing as Benjamin Cummings (http://www.aw-bc. Anatomy Review Graphics are used with permission of: Pearson Education Inc., publishing as Benjamin Cummings (http://www.aw-bc.com) Page 1. Introduction The structure of neurons reflects their function.

More information