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Chapter 10 Phys 2040 Principles Of
Physics 2 Workshop Questions Correctly
Answered 100% Right
Special senses
Sensors located in certain areas, vision, hearing, taste, smell, and equilibrium.
Somatic senses
Sensors distributed across body, touch, temperature, pain, itch, and proprioception.
Stimulus
Physical energy acting on a sensory receptor
Receptors acting as a transducer
something that converts stimulus to intracelular signal.
Conscious Stimulus Processing
Special senses and somatic senses
Stimulus processing in the subconscious
Somatic stimuli, and Visceral stimuli
Special Senses (Conscious Stimulus)
Vision
Hearing
Taste
Smell
Equilibrium
Somatic Senses (Conscious Stimulus)
Touch
Temperature
Pain
Itch
Proprioception
Somatic Stimuli (Subconscious Stimuli)
Muscle length and tension
Proprioception
Visceral Stimuli (Subconscious Stimulus
Thermoreceptors- heat differences
Photoreceptors- photons of light
Adequate stimulus
The particular form of energy a certain receptor responds to.
Receptive Field
Area where neurons can be stimulated
Area of the brain to process sensory information
Midbrain-visual information
Medulla oblongata- sound and taste
Cerebellum- balance/equilibrium
Thalamus- relay and processing station for all these above, and somatosensory information.
Olfactory information
travels from nose through first cranial nerve.
Perceptual threshold
level of stimulus intensity for you to be aware of a particular sensation.
The CNS must distinguish 4 properties for a stimulus.
- It's nature (modality)
- Its location
- Its intensity
Its duration
Sensory modality
nature of a stimulus is determined by the sensory neuron that detects it.
Labeled line coding
certain receptors will only send a certain signals to the brain
Location
Sensory regions in the cerebrum are organized with respect to incoming signals.
Phantom limb pain
When sensory neurons in the spinal cord become hyperactive, resulting in the sensation of pain in a limb that is no longer attached.
Summary of brain integration
- Each receptor is most sensitive to a certain type of stimulus.
- Stimuli above a threshold initiate action potentials in sensory neurons that project to CNS.
- Stimulus intensity/duration are coded by patteern of action potentials reaching the CNS.
- Stimulus location/modality are coded by which receptors are activated.
- Each sensory pathway projects to a specific region of the cerebral cortex.
4 Somatosensory Modalities
- Touch
- Proprioception
- Temperature
- Nociception.
Pathway
- Receptors are activated
- Receptor activation triggers action potentials.
- Primary sensory neurons synapse onto interneurons in spinal cord.
- All secondary neurons cross the midline of the body, so sensations from the left side of the body are processes in the right hemisphere of the brain.
- Secondary sensory neurons synapse onto tertiary sensory neurons in the thalamus.
- Ascending sensory tracts terminate in the somatosensory cortex.
Pacinian Corpuscles
Large, complex neurons that sense vibrations
Cold Receptors
Free nerve endings that terminate in subcutaneous layers of the skin
Nociceptors
Free nerve endings that detect a variety of strong noxious stimuli
Pain
brain's interpretation of information transmitted by nociceptors
Fast Pain
Sharp and localized. Rapidly transmitted by Alpha fibers (myelinated)
Slow pain
Duller and more diffuse. Carried by smaller c Fibers (unmyelinated)
Umami- Presence of organic compounds that might be nutritious.
The Ear
Allows us to hear and sense equilibrium
3 parts that make up the ear
- External Ear- pinna and ear canal
- Middle ear- Air-filled cavity that connects with the pharynx through the Eustachain tube.
- Inner ear- Consists of vestibular apparatus with semicircular canals.
Hearing
Our perception of energy carried by sound waves
Sound
brain's interpretation of the frequency, amplitude, and duration of the sound waves.
Loudness
Our perception of the sound's intensity
6 Steps of hearing
- Sound waves vibrate tympanic membrane
- Energy vibrates the malleus, incus and stapes
- Stapes is attached to the oval window, which vibrates to produce fluid waves in cochlea.
- Waves push on the membranes of the cochlear duct, and hair cells bend and open ion channels.
- Neurotransmitters release onto sensory neurons that create action potentials through the cochlear nerve.
- Energy from the waves transfers across the cochlear duct and is dissipated back to the middle ear of the round window.
3 forms of hearing loss
- Conductive hearing loss- sound cannot be transmitted either through the external ear or the middle ear.
- Central hearing loss- damage to the neural pathways between ear and the cerebral cortex
- Sensorineural hearing loss- damage to structures of the inner ear.
Equilibrium
mediated through hair cells in the vestibular apparatus and semicircular canals of the inner ear.
Vision
the translation of light reflected from objects into a mental image.
3 steps of vision
Presbyopia
Loss of accommodation. Often requires reading glasses.
Myopia
near sightedness
Hyperopia
Far sightedness,
Visible Light
wavelengths from 400-750 nm
Rods
function well in low light. Not as good at color vision, usually outnumber cones 20:1.
Cones
High acuity, color vision. Work best in daylight
Color-blindness
condition when a person has a defect in one of the three types of cones and has trouble distinguishing light.
