Copyright 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Properties of...

Functional Properties of Neurons Irritability

Ability to respond to stimuli & convert to nerve impulse

Conductivity Ability to transmit an impulse to other

neurons, muscles, or glands

Nerve Impulses: Electrical Conditions Resting neuron

The plasma membrane at rest is polarized Fewer positive ions are inside the cell than

outside the cell so cell interior is more negative Major ion inside cell is K+ Major ion outside cell is Na+

As long as inside remains more negative than outside, neuron stays inactive

Nerve Impulse: Action Potential & Generation Many types of stimuli excite neurons: light, sound,

pressure, smell, temperature, neurotransmitters Most neurons are excited by neurotransmitters

released by other neurons Result is always the same:

Na+ channels open & Na+ diffuses into the cell This causes Depolarization (inside becomes

more positive) This causes the neuron to transmit a signal

called an Action Potential (AKA Nerve Impulse)

Nerve Impulses

Figure 7.9a–b

Nerve Impulse: Action Potential & Generation Action potential

If the action potential (nerve impulse) starts, it is propagated over the entire axon

Impulses travel faster when fibers have a myelin sheath

Nerve Impulses

Figure 7.9c–d

Nerve Impulse: Action Potential & Generation Repolarization

K+ ions rush out of the neuron after Na+ ions rush in, which repolarizes the membrane

The sodium-potassium pump, using ATP, restores the original ion concentrations

This must happen before the neuron can conduct another impulse

Nerve Impulses

Figure 7.9e–f

Transmission of a Signal at Synapses Impulses are able to cross synapse to another nerve

Neurotransmitter is released from a nerve’s axon terminal

The dendrite of the next neuron has receptors that are stimulated by the neurotransmitter

An action potential is started in the dendrite Nerve impulse neurotransmitter nerve impulse

neurotransmitter effector “Electrochemical Event” because impulse is

electrical but next neuron is stimulated by a neurotransmitter, which is chemical

Transmission of a Signal at Synapses

Figure 7.10

Axonterminal

Vesicles

Synapticcleft

Actionpotentialarrives

Synapse

Axon oftransmittingneuron

Receivingneuron

Neurotrans-mitter is re-leased intosynaptic cleft

Neurotrans-mitter bindsto receptoron receivingneuron’smembrane

Vesiclefuses withplasmamembrane

Synaptic cleftNeurotransmittermolecules

Ion channels Receiving neuron

Transmitting neuron

Receptor

Neurotransmitter

Na+Na+

Neurotransmitterbroken downand released

Ion channel opens Ion channel closes

Figure 7.10, step 1

Axonterminal

Vesicles

Synapticcleft

Synapse

Receivingneuron

Figure 7.10, step 2

Axonterminal

Vesicles

Synapticcleft

Synapse

Receivingneuron

Synaptic cleft

Transmitting neuron

Figure 7.10, step 3

Axonterminal

Vesicles

Synapticcleft

Synapse

Receivingneuron

Synaptic cleft Neurotransmittermolecules

Transmitting neuron

Figure 7.10, step 4

Axonterminal

Vesicles

Synapticcleft

Synapse

Receivingneuron

Transmitting neuron

Figure 7.10, step 5

Axonterminal

Vesicles

Synapticcleft

Synapse

Receivingneuron

Transmitting neuron

ReceptorNeurotransmitter

Ion channel opens

Figure 7.10, step 6

Axonterminal

Vesicles

Synapticcleft

Synapse

Receivingneuron

Transmitting neuron

Na+Na+

Figure 7.10, step 7

Axonterminal

Vesicles

Synapticcleft

Synapse

Receivingneuron

Synaptic cleftNeurotransmittermolecules

Transmitting neuron

Na+Na+

The Reflex Arc Reflex—rapid, predictable, and involuntary

response to a stimulus Occurs over pathways called reflex arcs

Reflex arc—direct route from a sensory neuron, to an interneuron, to an effector

Types of Reflexes and Regulation Somatic reflexes

Stimulation of skeletal muscles Example: When you move your hand away

from a hot stove

Types of Reflexes and Regulation Autonomic reflexes

Regulate activity of: Smooth muscle Heart and blood pressure Glands

Example: saliva secretions, change in eye pupil size, digestion, excretion, blood pressure, sweating

5 Elements of a 3 Neuron Reflex 1. Sensory Receptor (reacts to a stimulus) 2. Sensory Neuron (afferent) 3. Integration Center (CNS) 4. Motor Neuron (efferent) 5. Effector Organ (stimulated to react)

The Reflex Arc

Figure 7.11a

Stimulus at distalend of neuron

Skin Spinal cord(in cross section)

Interneuron

Receptor

Effector

Sensory neuron

Motor neuron

Integrationcenter

The Reflex Arc

Figure 7.11a, step 1

Receptor

The Reflex Arc

ReceptorSensory neuron

The Reflex Arc

Interneuron

Integrationcenter

The Reflex Arc

Interneuron

Motor neuron

Integrationcenter

The Reflex Arc

Interneuron

Receptor

Effector

Sensory neuron

Motor neuron

Integrationcenter

Simple Reflex Arc

Figure 7.11b–c

Spinal cord

Sensory (afferent)neuron

Inter-neuron

Motor(efferent)neuron

Sensory receptors(stretch receptorsin the quadricepsmuscle)

Sensory receptors(pain receptors inthe skin)

Effector(quadricepsmuscle ofthigh)

Effector(bicepsbrachiimuscle)

Synapse inventral horngray matter

Simple Reflex Arc

Figure 7.11b, step 1

Spinal cord

Simple Reflex Arc

Spinal cord

Simple Reflex Arc

Spinal cord

Simple Reflex Arc

Spinal cord

Simple Reflex Arc

Spinal cord

Simple Reflex Arc

Figure 7.11c, step 1

Spinal cord

Simple Reflex Arc

Spinal cord

Simple Reflex Arc

Spinal cord

Inter-neuron

Simple Reflex Arc

Figure 7.11c, step 4a

Spinal cord

Inter-neuron

Simple Reflex Arc

Figure 7.11c, step 4b

Spinal cord

Inter-neuron

Simple Reflex Arc

Figure 7.11b–c

Spinal cord

Inter-neuron

Types of Reflexes and Regulation Patellar, or knee-jerk, reflex is an example of a

two-neuron reflex arc

Figure 7.11d

Copyright 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Properties of...

Documents

Muscular System. Excitability Irritability

Functional Properties of Neurons Irritability – ability to respond to stimuli Conductivity – ability to transmit an impulse The plasma membrane at rest

Manual Cummings

Richard Cummings 14517 Sedona Dr. RICHARD CUMMINGS … · 2020. 6. 2. · Richard Cummings 14517 Sedona Dr. Oklahoma City, OK 73142 RICHARD CUMMINGS Monday, June 22, 2020 Cornerstone

Elisabeth Cummings

Cummings Economics

Anger, irritability and mood swings - Headway Ireland · irritability or mood swings? Several things can work together to cause difficulties with managing mood swings, irritability

Pharmacologic Treatment of Severe Irritability and Problem ... · Pharmacologic Treatment of Severe Irritability and Problem Behaviors in Autism: A Systematic Review and Meta-analysis

Algorithm for Management of Irritability in Children …dentistry-ipce.sites.olt.ubc.ca/files/2016/11/PM1.pdfAlgorithm for Management of Irritability in Children and Adolescents with

Nervous Coordination Chapter 33. Irritability The ability to respond to environmental stimuli is a fundamental property of life. Single celled organisms

Ee Cummings

Aripiprazole in the real-world treatment for irritability

Coordination and control CO-ORDINATION / IRRITABILITY IN

Resting EEG Asymmetries and Levels of Irritability - Yolacaitlincoyiuto.yolasite.com/resources/PSYC350 FINAL 121815.pdf · Resting EEG Asymmetries and Levels of Irritability ... presentation

· 2015-05-07 · unicellular organisms irritability is a property of the protoplasm itself; there may also be various types of organelles that are sensitive to particular stimuli

Cummings Associates (Will Cummings)

Muscle Properties Irritability - A muscle irritability refers to the ability of the muscle to respond to a stimulus. Contractility - A muscle contractility

Anxiety, irritability, and agitation as indicators of

Irritability, Defiant and Obsessive-Compulsive Problems

Researches on Irritability of Plants Sir J C Bose