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Other Important Senses. Skin Senses, Taste, Smell, Balance. Touch. Sense of touch is a mix of four distinct skin senses pressure warmth cold pain. Skin Senses: Touch. Physical stimuli = mechanical, thermal, and chemical energy impinging on the skin
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Other Important Senses Skin Senses, Taste, Smell, Balance
Touch • Sense of touch is a mix of four distinct skin senses • pressure • warmth • cold • pain
Skin Senses: Touch • Physical stimuli = mechanical, thermal, and chemical energy impinging on the skin • Pathway: Sensory receptors -> the spinal column -> brainstem -> cross to opposite side of brain -> thalamus -> somatosensory (parietal lobe)
Skin Senses • Only pressure has identifiable receptors • All other skin sensations are variations of pressures, warmth, cold and pain • Temperature: free nerve endings in the skin • Pain receptors: also free nerve endings • Ex. Warm water + cold water = BURNING HOT!
PAIN • Pain tells the body that something has gone wrong. • Usually pain results from damage to the skin and other tissues. • Anhidrosis: rare disease in which the person feels no pain.
GATE-CONTROL Theory • Melzakand Wall (1965, 1983) • proposed that our spinal cord contains neurological “gates” that either block pain or allow it to be sensed. • One way to treat chronic pain is to stimulate it through massage, by electrical stimulation (ESTIM) or acupuncture • Massage causes competitive stimulation to pain thus reduces its effect. • ESTIM can distract muscles that are cramping and increases bloodflow
PAIN CONTROL • Pain can be controlled by a number of therapies including • drugs, surgery, acupuncture, exercise, hypnosis and even thought distraction • Burn victims can be distracted by allowing them to engage in illusory virtual reality • Brain scans show evidence of change in pain perception
The Chemical Senses: Taste • Taste (gustation) • Physical stimulus: soluble chemical substances • Receptor cells found in taste buds • Pathway: taste buds -> neural impulse -> thalamus -> cortex • Four primary tastes: sweet, sour, bitter, and salty • Taste: learned and social processes
The Chemical Senses: Smell • Smell (Olfaction) • Physical stimuli: substances carried in the air • dissolved in fluid, the mucus in the nose • Olfactory receptors = olfactory cilia • Pathway: Olfactory cilia -> neural impulse -> olfactory nerve -> olfactory bulb (brain) • Does not go through thalamus
Other Senses: Kinesthetic and Vestibular • Kinesthesis - knowing the position of the various parts of the body • Receptors in joints/muscles (detects bending, tautness, extensions) • Vestibular- equilibrium/balance • Semicircular canals & vestibular sacs (fluid shifts when head tilts) • Problems can occur with age, disease, or damage • Benign Paroxysmal Positional Vertigo (BPPV) • Calcium carbonate crystals in inner ear – sends false messages to brain