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69 Cards in this Set
- Front
- Back
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What do sensory organs monitor? |
Internal and external environment |
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What kind of stimuli does the sensory organs (receptors) detect? |
THey detect stimuli (changes in the environment) and transduction (the change of stimulus into electrical signal) (receptor potential) |
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Are sensory organs critical for homeostasis? And where do the signals they transmit go? |
It is critical for homeostasis, transmit signals (APs) from periphery to CNS |
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What is the function of Chemoreceptors? |
Detect changes in chemical concentration |
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What is the function of Thermoreceptors? |
Detect temperature changes |
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What is the function of Mechanoreceptors? |
Detect mechanical energy ( touch, pressure, vibration) |
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What is the function of photoreceptors? |
Detect light |
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What is the function of Nociceptors? |
Detect tissue damage (pain) |
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What is the Law of specific nerve energies? |
- Specific sensation felt for each receptor that is stimulated - Specific pathways to specific brain regions |
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(Sensory Adaptation) What are two functions of sensory adaptation? |
- Response of sensors to constant stimulation - Slowly adapting: tonic receptors, maintains constant firing as long as stimulus is applied - Rapidly adapting: phasic receptors, firing rate of receptor decreases with constant stimulus (smell your own breath, getting used to a swimming pool, rubber band on wrist) |
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(Receptor membrane potential) What happens during the first part of a transduction process? |
1. Sensors are most sensitive to one particular stimulus modality 2. Stimulus causes receptor potential 3. AP generated if threshold reached (trigger region)
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(Receptor membrane potential) What happens during the second part of a transduction process? |
4. Specific stimulus causes receptor potential 5. AP generated if threshold reached 6. Increase in stimulus strength above threshold causes increase in AP firing rate |
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(receptive field) What is a receptive field? |
Area/space/location of stimulus that leads to a response of a sensory neuron (touch, pain, temp, vision, etc) |
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(receptive field) What is a two-point discrimination? |
It is a measure of the density and size of touch receptive fields (not sensitivity) |
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(receptive field) Localization of a stimulus is a what? |
a measure of the size of receptive fields |
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(receptive field) Convergence of signals is directly related to what? |
Convergence of signals is directly related to size of receptive field |
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(receptive field) What order can receptive field apply to? |
first, second, or third order neuron |
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(AP to sensation) What does conduction do in regards to AP to sensation? |
relay info thru a specific sensory pathway to a CNS region |
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(AP to sensation) What does perception do in regards to AP to sensation? |
-Conscious awareness of stimulus -Evaluation of stimulus |
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(classification of sensory input) What does the somatosensory input do? |
-Sensors located over wide areas of the body -Info conducted to the spinal cord, then to the somatosensory cortex of brain |
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(classification of sensory input) What are the special senses in regards to sensory input? |
- Changes detected only by specialized sense organs in the head (cranial nerves) |
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(classification of sensory input) What is the (visceral sensory input)? |
-(Sensors in internal organs) -(Information to hypothalamus, limbic system, stec) |
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(somatosensory input) What are proprioceptors? |
-Sensory receptors in muscles, tendons and joints -Detect stretch in muscles, limb movements, positions of body parts, etc, -E.g, muscle spindles, golgi tendon organs |
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(somatosensory input) What are cutaneous receptors? |
-Sensory receptors in the skin -Touch and pressure -Heat and cold -Pain -Itch |
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What are the special senses? |
-Taste -Smell -Equilibrium -Hearing -Vision |
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(taste, gustatory sense) Point out three facts of taste cells. |
-Clustered into taste buds -Contain microvilli (tate hairs) that project to the external surface of the tongue -Cells depolarize when stimulated and release neurotransmitter from base of cell to associated sensory neurons |
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(taste, gustatory sense) Where is information relayed during a gustatory sense pathway? |
-Information relayed via cranial nerves VII and IX through thalamus to the inferior postcentral gyrus for perception |
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(taste, gustatory sense) What are five different taste sensations(stimuli)? |
1. Salty (high Na) 2. Sour (high H+ blocks K+ outflow channels) 3. Sweet (various organic molecules) 4. Bitter (toxins) 5. Umami (glutamate) |
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(taste, gustatory sense) If different tastes are derived from activation of different signaling pathways within the cells name the pathway of Saltiness and sourness. |
-Depolarization of taste cell driven by direct flow of Na+ into the cell through ion channels or H+ blocking K+ outflow |
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(taste, gustatory sense) If different tastes are derived from activation of different signaling pathways within the cells name the pathway of Sweet, bitter, and umami. |
- Binding of molecules to receptor proteins activates second messenger pathways leading to depolarization |
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(Smell, Olfaction) What type of neurons are olfactory receptors and where does the dendrite of a olfactory receptor extend to? |
-Bipolar neurons -Dendrite extends into nasal epithelium and ends in a ciliated knob |
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(Smell, Olfaction) Where do odorants bind to? |
-Odorants bind to receptor proteins on cilia - They also depolarize olfactory receptor |
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(Smell, Olfaction) Where do APs in olfactory receptors axons travel to? |
Olfactory bulb (CN I) through cribriform plate of ethmoid bone |
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(Smell, Olfaction) What do APs synapse to and where is the info relayed? |
-Synapse w/ association neurons in olfactory bulb -Info relayed to olfactory cortex (temporal lobe) and limbic system via olfactory tract |
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(inner ear) What does the Inner ear house? |
Houses structures for the senses of equilibrium and hearing |
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(inner ear) Describe the bony labyrinth and describe three distinct regions |
-Curved passageways w/in temporal bone 1. Vestibule/Semicircular canals - Equilibrium 2. Cochlea - hearing 3. Perilymph - fluid in bony labyrinth and around membranous labyrinth |
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(inner ear) Where is the membranous labyrinth located and describe one type of fluid inside of it. |
- Located w/in the bony labyrinth -Endolymph - fluid w/in the membranous labyrinth (high K+) |
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(equilibrium) When does equilibrium change and what does it do? |
-Changes in position and motion of head - Balance and coordination of body movement (sobriety tests) |
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(equilibrium) Describe the location of Hair Cells? |
-(location)Sensory cells w/in the inner ear -Stereocilia on surface -Similar in all inner ear receptors |
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(equilibrium) Describe three functions of Hair cells? |
1. Bending stereocilia opens K+ ion channels, depolarizing membrane 2. Depolarization causes neurotransmitter release to sensory nerve endings at base of hair cell 3. Excitation of axons sends APs along CN VIII |
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(Vestibular apparatus) Name four locations w/in the vestibular apparatus |
1. Bony labyrinth 2. Membranous labyrinth 3. Semi-circular ducts 4. Otolith
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(Vestibular apparatus) What are the main functions of the Semi-circular ducts and Otolith organs? |
Semi-circular: Hair cells detect rotation of the head in three different planes Otolith organs: Hair cells detect linear movement of head and direction of gravity
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(Vestibular apparatus) Where is info relayed during a synapse? |
Info is relayed via the vestibulocochlear nerve (VIII) to the cerebellum and medulla, then to the thalamus and cortex |
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(Otolith organs, maculae) Where are the otolith organs found? |
Found in vestibule, each with sensory hair cells |
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(Otolith organs, maculae) What is the otolithic membrane? |
-Stereocilia in jelly like membrane -Otoliths (CaCO3 crystals) |
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(Otolith organs, maculae) What causes the otolithic membrane to sag and what happens when it sags? |
-Linear movement or tilting of head causes otolithic membrane to sag 1. Bends sterocilia 2. Hair cells depolarize and release neurotransmitter 3. Stimulates vestibular neurons |
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(Ampulla) Where is the ampulla located and what does it contain? |
-Located in semicircular cancals -Contains hair cells covered by the cupula |
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(Ampulla) What happens during a rotation of the head? |
-It bends the cupula and stereocilia -Cells depolarize, releases neurotransmitter -Stimulates vestibular axons -APs along CN VIII to brain (when head rotates, ampulla moves and endolymph stays still, causing bending of capula) |
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(Ampulla) What happens at the beginning of a head rotation to the right? |
-The crista ampullaris rotates, but the inertia of the endolymph makes the fluid stay still
- This bends the cupula opposite to the direction of rotation |
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(Vestibular nystagmus) What stimulates the vestibular apparatus and what is the benefit of it? |
-Spinning (in a barany chair) stimulates the vestibular apparatus - It helps the eyes to keep focused while the head moves - if spinning stops abruptly, the eyes cont. to jerk in the direction of the spin |
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(hearing) In regards to hearing, describe a stimulus and hearing |
-Stimulus: sound waves are variations in air pressure -Hearing: neural perception of sound waves in the air |
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(hearing) In regards to hearing, describe pitch and loudness |
Pitch: Frequency of sound waves, humans can hear freq. between 20 and 20,000Hz
Loudness: Amplitude (size) of sound waves, measured in decibels |
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(Outer, external, ear) Name three structures of the outer ear |
1. Pinna (auricle): collects and channels sound waves 2. External auditory meatus: entrance into the temporal bone 3. Tympanic membrane: vibrates when struck by sound waves |
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(middle ear) Name the three auditory ossicles (convey vibrations to inner ear) in the middle ear |
1. Malleus: located against tympanic membrane 2. Incus 3. Stapes: linked to oval window |
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(middle ear) What does the Eustachian tube do? |
- It connects middle ear to pharynx to equilibrate pressure with atmosphere |
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(Cochlea) Where is the cochlea located and name the three snail-shaped tubes w/in it |
-Located in anterior portion of inner ear 1. Bony cochlea: filled w/ perilymph 2. Cochlear duct: part of membranous labyrinth, contains endolymph 3. Organ of corti: part of cochlear duct, hearing sensory receptor |
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(organ of corti) Describe the organ of corti |
-Forms the floor of the cochlear duct -Hair cells and supporting cells -Hair cells located on the basilar membrane -Contains the tectorial membrane as well |
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(organ of corti) What are the functions of the basilar membrane and tectorial membrane? |
-Basilar membrane: flexible, vibrates w/ sound stimulus -Tectorial membrane: lies on top of hair cells, stereocilia imbedded in membrane |
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(hearing transduction) What causes the basilar membrane to vibrate? |
Pressure waves |
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(hearing transduction) Hair cells move against what during a hearing transduction and what does it cause the stereocilia to do? |
-Hair cells move against tectorial membrane - Bends the stereocilia |
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(hearing transduction) During a hearing transduction neurotransmitters are released to nerve endings of what cranial nerve? |
Vestibulocochlear nerve (VIII) |
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(hearing transduction) Signals are relayed through where during a hearing transduction? |
Signals are relayed through the brainstem to thalamus and auditory cortex |
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(hearing transduction) During a hearing transduction what causes the basilar membrane to vibrate and what are the benefits of this? |
1. Fluid pressure waves in perilymph cause basilar membrane to vibrate - Louder sounds causes bigger vibratios - Low pitches and high pitches cause vibrations in different parts of the basilar membrane |
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What are the seven auditory athways? |
1. Organ of corti 2. Relays in medulla and pons 3. Bilateral path 4. Inferior colliculus 5. Medial geniculate nucleus 6. Temporal lobe 7. Tonotopic |
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(vision) What does vision perceive and what are the functions of photoreceptors? |
- Perception of light
- Photoreceptor: stimulated by photons of light, contain photopigments
- Photopigments: undergo chemical changes in response to light, induces changes in photoreceptors leading to receptor potential generation (transduction) |
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(vision) What area are signals sent during interpretation of vision? |
Signals sent to brain are interpreted in visual association areas |
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(vision) What is the pathway of vision? |
Retina-optic nerve -> optic chiasm -> optic tract-thalamus -> primary visual cortex -> visual association cortex |
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Name the pathway for Vision
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- Vision 1. Optic nerve 2. Optic chiasm 3. Optic tract 4. Thalamus 5. Primary visual cortex 6. Association visual cortices
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Name the pathway for Visual reflexes |
- Visual reflexes 1. Optic nerve 2. Optic chiasm - Hypothalamus 3. Optic tract 4. Superior colliculus |
