Presentation on theme: "YOUR OTHER SENSES. ANIMALS AND SENSES Dogs and sharks – great sense of smell Bats and dolphins – sonar Butterflies – taste receptors on feet Cats – can."— Presentation transcript:
ANIMALS AND SENSES Dogs and sharks – great sense of smell Bats and dolphins – sonar Butterflies – taste receptors on feet Cats – can hear up to 60,000 hz (humans only 20,000) Chameleons and seahorses – can look in two different directions at the same time Crickets – can hear using their legs Elephants – can hear in the infrasound range (1 hz) Giant Squid – eye has 1 billion receptors Frog – eardrum is on the outside of the body (behind eye) Mice – 100,000 hz Penguin – flat cornea, which allows underwater sight Rabbits – 17,000 taste buds (vs our 10,000)
VESTIBULAR SENSE Receptors provide information to your brain about the position of the head relative to the ground, linear acceleration, and rotational movements of the head Located in your inner ear (semicircular canals) Why do we sometimes feel dizzy when we are sick? Congestion in the middle ear affects this sense! Vestibular system (like the ear) also contains hair cells that are bent back and forth by surrounding fluid When extensive movement stops suddenly, the fluids may reverse course Head feels like it is moving in the opposite direction! Closely related to visual processing Need to maintain a stable view of our surroundings as we move When you rotate your head, your eyes will reflexively move in the opposite direction
KINESTHESIS (KINESTHETIC SENSE) Sense of position and movement of your body parts Sensors are in joints, tendons, bones, and ears When a limb falls asleep! Proprioception is the loss of this sense Can only move if they can see themselves
Infants who are touched regularly sleep better, remain more alert, reach cognitive milestones at earlier ages Premature babies gain weight faster and go home sooner if they are touched Skin is your largest and heaviest organ Different receptors respond to pressure, vibration, stretch, temperature, and pain Receptors can be found in your blood vessels, joints, and organs Headache, full stomach, etc Some receptors wrap around hair follicles and respond whenever a hair is pulled or bent Skin Spinal Cord Thalamus Sensory Cortex TOUCH
BRAIN AND TOUCH Your brain has neither touch nor pain receptors Evolutionary History? Intrusion into the brain = death, no need to feel your brain! Neurosurgeons can work on the brain while someone is awake! Increased input to an area can reorganize your sensory cortex Blind people and braille Thumbs and texting??
PAIN Some pain receptors respond to: Tissue damage, Temperature, Chemicals Fast, myelinated axons = sharp “ouches” Slower, unmyelinated axons = dull, aching sensations Skin receptors Spinal Cord Thalamus (short amount of time) Gate-Control Theory: Neurological gate that can be opened and closed Pain messages can be modified by other sensory signals Ever rub your elbow when you’ve hit it? Activation of touch fibers dilute pain information reaching your brain Helps explain why we can ignore pain Also, high levels of arousal = lessening in awareness of pain Endorphins also decrease the perception of pain Pain can be remembered differently depending on our moods Distracting people can increase pain tolerance Severe burn victims and a computer generated 3D world
PLACEBO EFFECT? ENDORPHINS? GATE CONTROL THEORY?
SMELL – OLFACTION Chemical sense Not as acute as our sense of smell and sight Evolutionary standpoint? Warning against danger (smoke, spoiled food) Hasn’t changed much! Smell is often times associated with memories Loss of smell and depression Anosmia: loss of smell Odor molecules bind to different receptors producing 10,000 odors Olfactory receptors regularly die and are replaced (4-6 week cycle) Information is not carried to the thalamus first! Goes to the olfactory cortex in the frontal lobe and to the amygdala Smell and emotions?
TASTE – GUSTATION (ALSO CHEMCIAL) Evolutionary advantage? Stopped us from eating poisonous or spoiled food and attracted us to foods that boosted our chance of survival We like fatty and sugary foods because our ancestors needed to store them for times of famine! Today, it may drive us to eat more than we need We taste: sweet, sour, salty, bitter, and umami (“savory” – MSG) Most papillae have 1-100 taste buds, which contain 50-150 receptor cells each Food molecules dissolve to interact with receptor cells Taste buds have a limited life! Reproduce themselves every week or two Mouth/tongue Medulla Thalamus Sensory Cortex Orbitofrontal Cortex (emotional pleasantess/unpleasantness) Experience and taste Taste preferences begin in the womb Cultural influences
Experience and smell Smelling an onion stimulus labeled “pizza” is rated higher than the same stimulus labeled “body odor” Chemical senses combine to make flavor Colds and food taste? Newborns are oblivious to salty tastes Older we get, the less taste buds we have reduces intensity of foods Broccoli and age? Appetite and age? Females v males and smell? Super tasters have more papillae than others More sensitive to taste and pain on the tongue! Tongue map is inaccurate