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30 Cards in this Set
- Front
- Back
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Nervous System |
→Rapid coordination & integration of body activities via electrochemical transmission |
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Neuron |
→electrical conducting cells of the nervous system |
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Synapse |
-Connection between a neuron & a second cell |
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Second cell can be: |
-another neuron -effector cell (muscle or gland) |
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Central Nervous System (CNS) |
Brain and Spinal Cord → Integration and interpretation of information |
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Peripheral Nervous System (PNS) |
Sensory and motor neurons → Transmit information to and from the CNS |
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PNS |
refer to PNS slide |
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Reflex |
involuntary motor response to stimulus without involvement of higher brain tissue → You don’t consciously think about it |
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Why do we have reflexes? |
To prevent potential tissue damage |
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Reflex arc- |
: nerve impulse pathway of a reflex →very simple; few neurons/few synapses |
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sensory neuron→(interneuron) → motor neuron |
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sensory neuron→ |
“Afferent”: sends message to CNS |
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→ motor neuron |
“Efferent”: sends message away from CNS to muscle (effector) |
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Monosynaptic reflex arc: - |
only 2 neurons; and one neuron-neuron synapse sensory neuron →motor neuron e.g. stretch reflexes, such as knee-jerk response |
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Muscle Spindle & Stretch |
-clusters of sensory cells in skeletal muscle -activated by stretch -spindles activate sensory neurons (afferent) |
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Exercise 5.1: Knee-Jerk Reflex |
Monosynaptic 1. Hit patellar ligament/tendon → attached quadricep muscle is stretched 2. Spindle stretched →sensory (afferent) neuron activated 3. Synapse between sensory and motor neurons in spinal cord (CNS) 4. Activated motor neuron (efferent) signals muscle (effector) to contract |
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Sensory Receptor: - |
receives information from the internal or external environment →transduces info.→ (activates neuron)→ information is transmitted to CNS |
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Chemoreceptors |
Taste and Smell |
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Mechanoreceptors |
Touch, pressure, stretch sound, balance |
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Photoreceptors |
Sight |
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Thermoreceptors |
Temperature |
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Cutaneous Receptors |
Touch Pressure Pain Hot Cold |
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Receptor Fields |
-area of the skin that can activate a single neuron |
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Receptor Fields Area of receptor field → |
inversely proportional to density of receptors - |
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Receptor Fields -few receptors → |
each receptor has large area (e.g. back of leg) |
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Receptor Fields -many receptors → |
each receptor has small area (e.g. finger tips) |
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2-Point Threshold |
-smallest distance between two points that are still perceived as two points 2 pts perceived → 2 receptors activated 1 pt perceived → 1 receptor activated |
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2-Point Threshold |
High density of sensory neurons (sm 2 pt threshold) → large associated portion of brain (sensory cortex) |
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Sensory Adaptation |
In response to constant stimulus → many receptors decrease their firing rate (phasic receptors) → We cease paying attention to certain constant stimuli e.g. odor, touch temp, light Without adaptation, you wouldn’t filter out unnecessary continuous info. Exception…pain receptors → maintain firing rate (tonic) →very slow or no adaptation |
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An Example of Sensory Adaptation Someone sprays perfume → you perceive odor Why? Eventually you stop noticing the odor (sensory adaptation) Why? |
Odor molecules detected by sensory receptors in nose → Receptor fires → Sensory receptor stops firing → no input into brain → no perception of odor |
