Muscle and Neural Tissues

Muscle

Specialized for contractionSpecialized for contraction Actin & myosinActin & myosin

Skeletal Muscle

StriatedStriated VoluntaryVoluntary Large cellsLarge cells FasciaeFasciae MultinucleateMultinucleate Nerve stimulatedNerve stimulated Attached to bonesAttached to bones

Cardiac muscle

StriatedStriated InvoluntaryInvoluntary Single nucleusSingle nucleus Intercalated disksIntercalated disks BranchingBranching Pacemaker cellsPacemaker cells Heart Heart

Smooth muscle

NonstriatedNonstriated InvoluntaryInvoluntary Spindle shaped cells Spindle shaped cells Single nucleusSingle nucleus Hormone or nerve stimulationHormone or nerve stimulation peristalsis\peristalsis\ Hollow organsHollow organs

Neural Tissue

Conduct impulsesConduct impulses BrainBrain Spinal cordSpinal cord Peripheral nervesPeripheral nerves

Neural TissueNeuronsNeurons

1 meter1 meter DendritesDendrites SomaSoma AxonAxon Synaptic (axon) terminalsSynaptic (axon) terminals

NeurogliaNeuroglia Support cells – phagocytic, isolation, Support cells – phagocytic, isolation,

framework, connect to blood vesselsframework, connect to blood vessels

Neuron diagram

Action Potential (impulse)

Stimulus produces electrical impulseStimulus produces electrical impulse affects cell membrane of the dendriteaffects cell membrane of the dendrite alters membrane properties of soma alters membrane properties of soma produces massive change in produces massive change in transmembrane transmembrane

potentialpotential sweeps along the length of the axonsweeps along the length of the axon Skips along Nodes of Ranvier in between myelin Skips along Nodes of Ranvier in between myelin to synaptic terminalsto synaptic terminals

Synapse - junction between nerve cells, a very small gap impulse reaches synaptic terminalsimpulse reaches synaptic terminals release of a chemical neurotransmitterrelease of a chemical neurotransmitter AcetylcholineAcetylcholine is the neurotransmitter for muscle is the neurotransmitter for muscle

stimulation, dopamine and serotonin are othersstimulation, dopamine and serotonin are others crosses synapse by diffusion and contacts the crosses synapse by diffusion and contacts the

adjacent cell membraneadjacent cell membrane Next cell may be another neuron or some other Next cell may be another neuron or some other

cell (muscle, gland)cell (muscle, gland)

Curare

a poison used by Native Americansa poison used by Native Americans Curare binds to acetylcholine receptors and Curare binds to acetylcholine receptors and

blocks themblocks them Muscles are paralyzed by being stuck in the Muscles are paralyzed by being stuck in the

relaxed staterelaxed state CholinesteraseCholinesterase is an enzyme which breaks is an enzyme which breaks

down acetylcholine and stops a contractiondown acetylcholine and stops a contraction

Tetanus

A toxin that travels backwards through A toxin that travels backwards through neurons to the spinal cordneurons to the spinal cord

Blocks inhibiting neuronsBlocks inhibiting neurons Causes muscles spasms and tetanii Causes muscles spasms and tetanii

(extended contractions) that can tear (extended contractions) that can tear musclesmuscles