Question

Sensory Systems

General Sensory

1. Stimuli in the environment are detected by ___________. _________ detect stimuli in the outside environment while ________ detect internal stimuli. ________ detect chemicals; ________ detect pressure; ________ detect photons; _________detect changes in shape; ________ detect changes in muscle length
2. Receptors can only detect stimuli that is presented in the ___________. Smaller/larger receptive field allow for better precision. Receptors generate ___________ which triggers __________ in sensory neurons. Sensory neurons relay information to the _________ then to the __________ where stimuli is perceived.

Taste

1. Taste receptors are ___________; they are located in _________. ________ trigger salty taste; ________ trigger sweet taste; ________ trigger bitter taste; _______ trigger umami taste; ______ trigger sour taste.
2. _________ and _______ chemicals directly enter taste cells to depolarize them. __________ chemicals bind to receptors which activate second messenger system.
3. Taste cells activate neuron is CN _________ which relay the information to the __________ and then to __________ then finally to the _________ where taste is perceived.

Smell

1. Olfactory receptors are located _____________. Binding of odorants to olfactory receptors activates _________ which activates ___________ enzyme which converts __________ to ________. cAMP opens ________ to _______ the olfactory neuron. The olfactory neurons synapse in the _________ and then to the _________ where odor is perceived.

Vision

1. __________ photoreceptors are used for bright light conditions and for seeing _______. ________ photoreceptors are used form dim light conditions. There are ______types of cones. Blue cones respond best to light of _____; Red cones respond best to light of ________; and green cones respond best to light of _________. Rods respond best to light of _______.
2. The part of the photoreceptor that responds to light is the __________ which is made of ________ and ________.
3. In the dark, cGMP opens _________ on the photoreceptors which allows ______ to enter. This is called the __________ which depolarizes the ________ which releases ________ to inhibit bipolar cells. As a result, bipolar cells can’t activate __________. As a result, no _________ is generated in the optic nerve.
4. In the light, photons of light strike to photopigments to convert ________ to _______. This change activates _________ which activates __________ which converts cGMP to ________. A decrease in cGMP decreases the _________ current. As a result, bipolar cells are no longer inhibited by _______. Bipolar cells then stimulate _________ which generate action potentials in the ________.
5. The scotopic system uses many _________ to activate fewer ________ which activate fewer _________. This is an example of __________. This system uses _________ to respond to low intensity light
6. The photopic system uses __________ to activate __________ to activate __________. Due to the lack of __________, this system is not suitable for __________ but it is ideal for _________.
7. Visual pathway
   1. Bipolar cells synapse with _______ in the retina which, in turn, synapse in the ________; third order neurons then terminate in the _________ where vision is perceived.
8. Vision abnormalities
   1. _________ is also called nearsightedness; in this condition image comes into focus _________
   2. _________ is also called farsightedness; in this condition, image comes into focus ________
   3. _________ is condition that prevents the image from coming into focus
   4. _________ is normal vision

Hearing

1. The pitch of a sound is based on its ________. The loudness of sound is based on its ________. Loudness is measure using a _________ scale. 20 db is ________ times louder than the hearing threshold.
2. The receptor for hearing is the _________ which is located in the _________. The receptor has ______ and _______ hair cells. The __________ are responsible for hearing and the _______ are responsible for cochlear tuning.
3. The ________ are activated when their stereocilia __________ and are inhibited when the stereocilia __________. Bending of the stereocilia towards the _______open ________ to allow _______ to enter the cells. This causes depolarization of the _______ which activates ________.
4. Pathway
   1. Auditory nerve synapse in the _________ and activate secondary neurons which project to the ________ to activate tertiary neurons which project to the ________ to activate quarternary neurons which project to the _________ to activate 5^th order neurons that terminate in the _______ where hearing is perceived.  
5. Hearing loss
   1. Damage to the ________ leads to sensorineural hearing loss whereas obstruction or damage to the ________ may lead to conduction hearing loss.

Equilbrium

1. _____________ detect angular movements of the head; the _________ detects vertical movements of the head; the ________ detects horizontal movements of the head.
2. The equilibrium structures (apparatus) contain ________ which are depolarized when _________. These cells then activate __________ which terminate in the _________. Neurons then project to the _________ and then to the ________.

Answer 1

General Sensory

1. Stimuli in the environment are detected by sensory receptor .Peripheral nervous system detect stimuli in the outside environment while Central nervous system detect internal stimuli.Chemoreceptors detect chemicals; Mechanoreceptors detect pressure; Photoreceptors detect photons; Meissner's corpuscle detect changes in shape; Muscle spindles detect changes in muscle length
2. Receptors can only detect stimuli that is presented in the receptive field Smaller/larger receptive field allow for better precision. Receptors generate stimulus which triggers action potential in sensory neurons. Sensory neurons relay information to the interneuron then to the central nervous system cerebral cortex where stimuli is perceived.

Taste

1. Taste receptors are chemoreceptors; they are located in taste buds on the tongue. ion channels trigger salty taste; G-protein coupled taste receptors trigger sweet taste; G-protein coupled taste receptors trigger bitter taste; G-protein coupled taste receptors trigger umami taste; ion channels trigger sour taste.
2. DAG (Diacyl Glycerol) and IP3 chemicals directly enter taste cells to depolarize them. G-proteins chemicals bind to receptors which activate second messenger system.
3. Taste cells activate neuron is CN VII,IX, which relay the information to the Ganglion(Geniculate,petrosal,nodose) and then to Nucleus of tractus solitarius then finally to the Primary gustatory cortex_where taste is perceived.

Smell

1. Olfactory receptors are located in olfactory epithelium of nasal cavity Binding of odorants to olfactory receptors activates G-olfactory protein which activates adenyl cyclase enzyme which converts ATP to cAMP. cAMP opens channel to activate the olfactory neuron. The olfactory neurons synapse in the glomerulus and then to the olfactory cerebral cortex where odor is perceived.

Vision

1. Cones photoreceptors are used for bright light conditions and for seeing colors. Rods photoreceptors are used form dim light conditions. There are three types of cones. Blue cones respond best to light of _blue Red cones respond best to light of red; and green cones respond best to light of green. Rods respond best to light of black_.
2. The part of the photoreceptor that responds to light is the disk which is made of opsin and retinal
3. In the dark, cGMP opens __ion channels_______ on the photoreceptors which allows __Na+ & Ca2+____ to enter. This is called the __EPSP________ which depolarizes the _photoreceptor______ which releases __glutamate______ to inhibit bipolar cells. As a result, bipolar cells can’t activate __ganglion cells________. As a result, no _action potential________ is generated in the optic nerve.
4. In the light, photons of light strike to photopigments to convert __11-cis-retinal______ to __all-trans retinal_____. This change activates _opsin________ which activates __phosphodiesterase enzyme________ which converts cGMP to __broken down______. A decrease in cGMP decreases the _action potential(hyperpolarization)________ current. As a result, bipolar cells are no longer inhibited by ___glutamate____. Bipolar cells then stimulate __ganglionic cells_______ which generate action potentials in the _optic nerve_______.
5. The scotopic system uses many ____rhodopsin____ to activate fewer __G-protein______ which activate fewer __second messenger cascade______. This is an example of _achromatic vision_________. This system uses ___rod cells______ to respond to low intensity light
6. The photopic system uses ____photopsin______ to activate _G-protein_________ to activate ___second messenger cascade___. Due to the lack of ___rhodopsin_______, this system is not suitable for ______night vision____ but it is ideal for __day-time vision_______.
7. Visual pathway
   1. Bipolar cells synapse with _ganglion cells______ in the retina which, in turn, synapse in the __optic nerve______; third order neurons then terminate in the __visual cerebral cortex_______ where vision is perceived.
8. Vision abnormalities
   1. __myopia_______ is also called nearsightedness; in this condition image comes into focus ___in front of the retina_____
   2. _____hypermetropia____ is also called farsightedness; in this condition, image comes into focus _behind the retina_______
   3. _____presbyopia____ is condition that prevents the image from coming into focus
   4. _____20/20____ is normal vision

Hearing

1. The pitch of a sound is based on its ___frequency_____. The loudness of sound is based on its _intensity/energy_______. Loudness is measure using a ____decibel_____ scale. 20 db is __100______ times louder than the hearing threshold.
2. The receptor for hearing is the _hair cells______ which is located in the _basilar membrane_______. The receptor has __organ of corti____ and _______ hair cells. The ___hair cells_______ are responsible for hearing and the __organ of corti_____ are responsible for cochlear tuning.
3. The __kinocilia______ are activated when their stereocilia ____shear____ and are inhibited when the stereocilia _____rest_____. Bending of the stereocilia towards the __kinocilia_____open _ channels_______ to allow ___Ca2+_K+___ to enter the cells. This causes depolarization of the _hair cell______ which activates ___auditory nerve____.
4. Pathway
   1. Auditory nerve synapse in the ____spiral ganglion_____ and activate secondary neurons which project to the _cochlear nuclei______ to activate tertiary neurons which project to the inferior colliculi________ to activate quarternary neurons which project to the __medial geniculate body_______ to activate 5th order neurons that terminate in the __Area no.41 on cerebral cortex_____ where hearing is perceived.  
5. Hearing loss
   1. Damage to the __Cochlear nerve______ leads to sensorineural hearing loss whereas obstruction or damage to the ___outer/middle ear_____ may lead to conduction hearing loss.

Equilbrium

1. ____Semicircular canals_________ detect angular movements of the head; the __saccule_______ detects vertical movements of the head; the _utricle_______ detects horizontal movements of the head.
2. The equilibrium structures (apparatus) contain _stereocilia_______ which are depolarized when ___moves______. These cells then activate __central processes________ which terminate in the __vestibular ganglia_______. Neurons then project to the _________ and then to the __thalamus______.