Presentation on theme: "Feedback A response resulting from some form of input as in a reflex reaction that results from a stimulus The source of our interaction with the physical."— Presentation transcript:
1FeedbackA response resulting from some form of input as in a reflex reaction that results from a stimulusThe source of our interaction with the physical worldInvolves input which is interpreted at some neural level
2Sources of InputSensory Transduction - The ability to detect and translate a stimulus.Sensory Receptors - The systems or organs which receive specific stimuli.
3Examples of Sensory Receptor Systems Visual ApparatusVestibular apparatus – Detects the orientation of the head with respect to the direction of gravitational pull or acceleration. Found in the structure of the inner ear.Auditory ApparatusSensory Nerves
4Classification of Sensory Receptors Based on the Source of the Stimulus Interoreceptors – Detect input from within the bodyProprioceptors – Detect input regarding the position of body parts relative to each other.Exteroreceptors – Detect input from outside of the body.Teloreceptors – Deal with stimuli not touching the bodySomatoreceptors – Deal with stimuli that contact the body’s surface.
5Classification of Sensory Receptors Based on the Type of Stimulus Chemoreceptors – Sensitive to chemicalsTasteSmellDetection of lower pH in blood caused by increased CO2 levels. (Results in increased breathing rate.)Mechanoreceptors – Stimulated by mechanical forces, usually pressureSense of touchBaroreceptors which detect degree of lung inflation
6Classification of Sensory Receptors Based on the Type of Stimulus (continued) Proprioceptors – Sense changes in the conditions of muscle and connective tissueMuscle spindlesGolgi tendon organsThermoreceptors – Detect temperature changesPain ReceptorsAlso called nociceptorsVital to detecting dangerous compromise of tissuesPhotoreceptors – Detect light
7Exteroceptive Feedback Extensor-thrust reflex – Pressure on mechanoreceptors in the feet promotes contraction of extensors of the legs.Provides the foundation for standing balance without conscious controlWithdrawal reflex – A protective reflex causing sudden withdrawal from a source of pain. Also called the flexor reflex.
8Exteroceptive Feedback (continued) Crossed-extensor reflex - .2 to .5 seconds after the flexor reflex is activated in one limb, the crossed extensor reflex produces extension in the opposite limb.The extending limb extends to push away from the painful stimulus which caused the activation of the flexor or withdrawal reflex.
9Cutaneous (Skin) Receptors Detect changes in surface condition of the skin (deformation)Near the skin’s surface (These receptors provide information about light touch and low frequency vibration):Meissner’s corpusclesMerkel’s discsRuffini corpuscles
10Cutaneous (Skin) Receptors (continued) Deeper receptors in the skinPacinian corpusclesRespond more to deep compression and high frequency vibration
15Joint ReceptorsModified Ruffini corpuscles and Modified Pacinian corpusclesFound in deeper tissues, joint capsules, and ligamentsDetect pressure, high frequency vibration and stretch in joint capsules and ligamentsDetect possible compromise of joint structure as well as angular position of joints
16Applications of Proprioceptive and Exteroceptive Feedback Relieving muscle crampsMuscle cramps often occur in a muscle which is in an extremely shortened stateTension in tendons actually decreases in this stateGolgi tendon activity is reduced (Golgi tendon organs reduce muscle tension in response to tension in the tendons)EXAMPLE: Swimmers are prone to calf cramps, possibly due to prolonged plantar flexion during exercise.Passive stretching (which would activate the Golgi tendon organs) often relieves muscle cramps
17Applications of Proprioceptive and Exteroceptive Feedback Stretching exercises (PNF) – Use feedback to reduce tension in musclesWind-up (preparative phase) – Uses the sense of stretching and acceleration in muscle tissue to increase force output in agonists and reduce antagonist resistance
18Applications of Proprioceptive and Exteroceptive Feedback Kinesthesis – Senses of body and limb position and velocity, joint angle, and degree of pressure and tension being applied are critical for the successful performance of many skills.Useful for movements involving rapid changes of whole body orientation (diving, gymnastics, etc.)Important for fine motor control (playing a musical instrument)
19Conflicts in Input Sources Input from vision will override information from other sensory systems.Test subjects were placed on a surface that remained stationary while visual reference points were subtly moved.Although the body’s sensory apparatus should have indicated that the subjects were still balanced, the subjects responded as though balance was being lost, strictly due to visual input.
20Exerciseincreases oxidative and therefore signal transmitting capacity of neurons