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The Synapse and Reflexes
10

The Synapse and Reflexes

Feb 23, 2016

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The Synapse and Reflexes. Structure of a Synapses. Synapse: Is a junction where a axon interacts with another neuron Presynaptic Terminal : End of the axon Postsynaptic Membrane: Membrane of the dendrite Synaptic Cleft: Space between the presynaptic membrane and postsynaptic membrane - PowerPoint PPT Presentation
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Page 1: The  Synapse and Reflexes

The Synapse and Reflexes

Page 2: The  Synapse and Reflexes

Synapse: Is a junction where a axon interacts with another neuron

Presynaptic Terminal: End of the axon

Postsynaptic Membrane: Membrane of the dendrite

Synaptic Cleft: Space between the presynaptic membrane and postsynaptic membrane

Synaptic vesicles: Stores chemical neurotransmitters

Structure of a Synapses

Page 3: The  Synapse and Reflexes

Excitatory - increase membrane permeability, increases chance for threshold to be achieved to trigger an action potential

Inhibitory - decrease membrane permeability, decrease chance for threshold to be achieved to trigger an action potential

Neurotransmitters

Page 4: The  Synapse and Reflexes

Acetylcholine ACh - stimulates muscle contraction

Norepinephrine & Dopamine (sense of feeling good, low levels = probable cause to depression)

Serotonin (sleepiness)Endorphins (reduce pain, inhibit receptors)

Types of Neurotransmitters

Page 5: The  Synapse and Reflexes

Reflex: An involuntary reaction in response to a stimulus

Reflex Arch: Pathway in which a reflex occurs.

Reflexes

Page 6: The  Synapse and Reflexes

Sensory Nerves - conduct impulses into the brain or spinal cord

Motor Nerves - carry impulses to muscles of glands from the brain and spinal cord

Mixed Nerves - contain both sensory and motor nerves

Types of Nerves

Page 7: The  Synapse and Reflexes

5 steps of Reflex Arch1. Sensory Receptor 2. Afferent neuron 3. interneuron 4. Motor neuron 5. Effector organ

Reflex Arch Pathway

Page 8: The  Synapse and Reflexes
Page 9: The  Synapse and Reflexes

Reflex arc - only includes a few neuronsReflex Behavior – automatic and

subconscious responsesStretch or Knee-jerk reflex – Muscles

contract when applied force it put on them (patellar reflex)

Withdrawal reflex - avoidance of painful stimuli

Nerve Pathways

Page 10: The  Synapse and Reflexes

Converging Pathways: More than one neuron synapses converge on the same neuron. (more than one neuronal pathway)

Diverging Pathways: The axon from one neuron divides or diverges with one or more neurons. (one neuronal pathways can diverge into multiple pathways)

Neuronal Pathways