Physiology 4
Which regions of the brain are involved in the control of the autonomic system?
-Hypothalamus -Pons -Medulla
What are TRP channels, how do they signal, and what do they produce?
Transduction in thermoreceptors involves a class of proteins known as transient receptor potential (TRP) channels that are permeable to certain cations. TRP channels also play a role in the transduction mechanisms of other types of sensory stimuli, including pain and gustation. Different types of TRP channels are responsible for the transduction mechanisms of different sensory stimuli.
How are the two divisions of the autonomic nervous system arranged? Where do they originate from? What are the lengths of the different neurons?
[Preganglionic neurons]: Originate in the CNS and project to and autonomic ganglion [Postganglionic neurons]: Have cell bodies in the ganglion and project to the target tissues [Divergence]: Specific to Sympathetic. One preganglionic neuron synapses 8 or 9 postganglionic neurons [Sympathetic pathway]: Originate in the thoracic and lumbar regions. -Short preganglionic neurons and long postganglionic neurons [Parasympathetic pathway]: Originate in the brain stem (cranial nerves) and the sacral region -Long parasympathetic preganglionic neurons and short postganglionic neurons
What are presbyopia, myopia, and hyperopia? How can these distortions be fixed?
[Presbyopia] -Loses flexibility with age [Myopia(Nearsighted)] -Can see near, but cannot see far -Concave lens(凹面) moves focal point further back [Hyperopia(Farsighted)] -Can see far, but cannot see near -Convex lens(凸状) moves focal point forward
How do cones and rods differ?
[Rods]: VERY sensitive to light -Not sensitive to color -Used in dim light(lower amounts of light) -Less acuity [Cones]: LESS sensitive to light -sensitive to color -Red, blue, and green cones -Used in bright light -Higher acuity [Rods and Cones] Inner segment -Contains most organelles and nucleus Outer segment -Flattened membranous discs ・Contain photopigments that absorb light ・Continuously added and removed (Recycled) ・Disc shape help in trapping light
What are the divisions of the efferent division of the nervous system and what are their effector tissue?
[Somatic motor neuron] -Skeletal muscle [Autonomic neurons]: Sympathetic and Parasympathetic -Cardiac muscle -Smooth muscle -Exocrine glands/cells -Some endocrine glands/cells -Some adipose tissue
What stimuli do pain receptors respond to?
-Pain receptors that depolarize when tissue are damaged -Stimuli can include heat, cold, pressure, or chemicals -Glutamate and substance P are the main neurotransmitters -Perception of pain can be enhanced by emotions, concepts, and expectations -Pain reduction depends mainly on endogenous opioids
What is mass activation of the sympathetic? What property allows this to occur?
-Preganglionic neuron can diverge at chain ganglia and innervate multiple postganglionic neurons(Mass activation) -can activate many tissues quite quickly
Where do the pre and post ganglionic neurons synapse? What neurotransmitters are used pre and postganglionic synapse and at synapse between postganglionic neuron and target tissue? What receptors would be found on the dendrites of the postganglionic neurons and what receptors would be found on the target tissue?
-Preganglionic neuron enters sympathetic chain ganglion through white ramus -Synapses with postganglionic neuron in ganglion -Postganglionic neuron leaves sympathetic chain ganglion through gray ramus -Both sympathetic and parasympathetic preganglionic neurons release ACh onto nicotinic cholinergic receptors on the postganglionic cell -Most postganglionic sympathetic neurons secrete Norepinephrine onto adrenergic -Most postganglionic parasympathetic neurons secrete ACh onto muscarinic cholinergic receptors on the target cell -Sympathetic cholinergic neurons: A few sympathetic postganglionic neurons secrete ACh
What is lateral inhibition and what is the mechanism of this?
-Receptors where touch is the strongest are stimulated more than areas where touch is lighter -Receptors that are most strongly stimulated inhibit those around them -This allows us to perceive well-defined sensations at a single location instead of a "fuzzy(曖昧な)" border -This process occurs in the CNS
Where does information of the different field of vision signal to? What are the different pathways of for visual neural information and what kind of information do they code for?
-Right field falls on left side of retina -Left field falls on right side of retina Left visual field right side of brain Right visual field left side of brain [Ceniculostriate system] -Give us what are we looking at -Lateral geniculate nucleus of thalamus to striate cortex [Tectal] -Where? -Neurons of superior colliculus activate motor pathways to eyes and body
Somatoesthetic information from the right side of the body goes to which half of the somatosensory cortex? What is this termed?
-Right sensation goes to left cortex -Contralateral
What type of information goes to somatosensory cortex? What is somatotopy? Which part of the bodies have larger regions of the cortex devoted to them?
-Somatesthetics -Proprioception (From skin and muscles and tendons) -[Somatotopy]The point-for-point correspondence of an area of the body to a specific point on the central nervous system. Density of receptor -Hand
Which tissue are under tonic control? Which division of the autonomic exhibits tonic control?
-Sweat gland -Smooth muscle in the blood vessels
How do cold receptors signal?
-There are many more receptors that respond to cold than to hot -Located close to the epidermis -Stimulated by cold and inhibited by warm -Some cold receptors also respond to menthol -The temperature range of response is 8~28℃ -Also serves as an ion channel for sodium and calcium; a transient receptor potential(TRP) channel
***Can you describe release and removal of norepinephrine at the neuroeffector junction?
1) AP arrives at the varicosity 2) Depolarization opens voltage-gated Ca2+ channels 3) Ca2+ entry triggers exocytosis of synaptic vesicles 4) NE binds to adrenergic receptor on target 5) Receptor activation ceases when NE diffuses away from the synapse 6) NE is removed from the synapse 7) NE can be taken back into synapse vesicles for re-release 8) NE is metabolized by monoamine oxidase(MAO)
***How does signaling take place in the cochlea (all the detail)? What is function of inner and outer hair cells?
1) Movement of tectorial and basilar membrane from pressure waves of perilymph results in force that bends stereocilia 2) Bending of stereocilia results in opening of K+ channels in the stereocilia 3) Endolymph is high in K+ so will move into cell down its concentration gradient 4) Depolarization of cell 5) Release of glutamate to associated sensory neuron
How does signaling occur in olfaction what is the pathway of neural information and how does this differ from the other special senses?
1) Odor molecule binds to receptor (G-protein couple receptor) 2) Activates G-protein which activates adenylate cyclase which forms cAMP 3) cAMP open channel allow Na+ and Ca2+ which depolarizes bipolar neuron -Bipolar neuron projects up through cribiform plate to olfactory bulb -Synapse with second order neuron in spherical arrangement - Glomeruli ・Glomerulus receives input from one type of sensory cell ・Periglomerular cell improves identification of odor by inhibiting neighboring glomerulus ・Interneurons within glomerulus help sharpen smell -lateral inhibition -Second order projects to cerebral cortex - olfactory cortex No projection to Thalamus
What are the functions of the pigmented layer?
1) Phagocytosis of distal discs of photoreceptors 2) {Melanin]:Absorb the scattered light 3) Supply nutrient to photoreceptors-Blood supply is in choroid plexus 4) Suppression of immune attack 5) Recycles visual pigments back to photoreceptors 6) Stabilize ion composition for proper response to light
Process: Bending opens ion channels
1) Pressure wave bends stereocilia 2) K+ channels open, K+ rushes in 3) Membrane depolarizes 4) Ca2+ flows in 5) Synaptic vesicles fuse 6) Neurotransmitter is released
What are the 2 major structures that form the inner ear? What fluid are contained in both and how do these fluids and how do they differ from one another?
Cochlea Vestibular apparatus [Membranous labyrinth] -Tubular structure filled with endolymph fluid -Endolymph high in K+ [Bony labyrinth] -Houses membranous labyrinth -Perilymph lies between bone and membranous labyrinth
What are the different categories of deafness? How could these be treated?
Conduction deafness -Conduction of sound waves through external auditory meatus is blocked -Middle ear infection causes resistance to movement of ossicles -Hearing aid: Amplify sound Sensorineural deafness -Loud noises destroy hair cells -Damage to parts of brain involved in sound -Cochlear implant: Stimulate dendrites that are still viable
How is the iris regulated? What divisions of the nervous system innervate it.
Controls the amount of light enter the eye by actions by 1) Radially arranged smooth muscle 2) Circularly arranged smooth muscle In dim light -Sympathetic nervous system contracts radially arrange smooth muscle(Dilation) -Contract radial muscle and Relax circular muscle In bright light -Parasympathetic contracts circular muscle(Constriction) -Relax radial muscle and Contract circular muscle What would you use to dilate eye? -Muscarinic antagonist
Taste Pathways
Facial, vagus, and glossopharyngeal nerves ⇩ Medulla oblongata (Crosses over) ⇩ Thalamus ⇩ Primary gustatory cortex of insula, somatosensory cortex of parietal lobe, and prefrontal cortex
What are the regions of highest acuity? What factors allow acuity to be highest there?
Fovea centralis NO convergence In fovea, 1 photoreceptor to 1 ganglion cell
What kind of the tissue are the vestibular sensory cells? How does signaling take place in organs of the vestibular apparatus?
Hair cells [Stereocilia] Modified epithelium with modified microvilli -Stereocilia arranged in rows of increasing height [Kinocilium} Touches highest row of stereocilia -Bending in direction of kinocilium results in opening of K channels resulting release of neurotransmitter -Bending in opposite direction causes hyperpolarization of cell
***Where in the cochlea would high (and low pitch) pitch sounds signaling? How would loudness effect signaling ? What is meant by tonotopic?
Higher frequency: Displacement of basilar membrane would occur in first turn of spiral Lower frequency: Displacement of basilar membrane would occur in later turns of spiral -As vibrations travel through cochlea, they are dampened(減退)⇒Outer hair cells amplify vibrations(Cochlear amplifiers) -The louder the sound (amplitude) the greater the displacement of basilar membrane -Greater bending of stereocilia -Greater release of neurotransmitter -More frequency of APs -Higher frequency of AP perceived by brain as louder noise [Tonotopic Organization]: Neurons associated with different hair cells from different regions project to different regions of auditory cortex
***How does the signaling of the rods and cones take place? The photoreceptor cells and the pathway in which the information follows.
In the dark, 11-cis retinal bound to Rhodopsin -cGMP is available keeps Na Channels open causing depolarization (dark current) 1) cGMP levels are high because phosphodiesterase does not converting it to GMP. 2) High cGMP keeps Na channel open 3) Sensory cells depolarize 4) Neurotransmitters(inhibitory) are released 5) They are stopping the bipolar cell from signaling In light, conversion to all-trans-retinal -Alpha subunit activates phosphodiesterase -Activate phosphodiesterase which catalyze cGMP to GMP -Closing Na channels and hyperpolarizing -Cause
How do intero and exteroreceptors differ and can you recognize and example of each?
Interoceptors: Detect chemical changes within the body Exteroceptors: Detect changes from outside the body; include taste and smell 1. Taste responds to chemicals dissolved in food and drink 2. Smell responds to chemical molecules from the air 3. Olfaction greatly influences gustation
What are the different types of sensory receptors? Can you recognize and example of each?
Interoreceptors: Receive stimuli from inside the body e.g. Baroreceptors(blood vessel) & Proprioreceptors(joints Exteroreceptors: Receive stimuli from outside the body e.g. Cutaneous receptors & photoreceptors(light) Chemoreceptors: Gustation(taste), Odor(smell) Mechanoreceptors: Ear, Pressure Photoreceptors: Eye Thermoreceptors: Warm, cold Nociceptors: Pain, High heat/ cold, Chemicals, Glutamate
How does receptive field and the amount of convergence of the photoreceptors effect acuity?
Many rods will converge onto one ganglion cell -Receptive field associated with ganglion cell is larger In fovea, on rod is associated with one ganglion cell -Receptive field associated with this ganglion cells is much smaller
What are the effects of acetylcholine released from the parasympathetic postganglionic neuron on the target tissue? Why can there be differ effects from the same neurotransmitter?
Muscarinic ACh receptors(5 types) -Produce parasympathetic nerve effects in the heart, smooth muscle, and glands -G-protein-coupled receptors (receptors influence ion channels by means of G-proteins) Hyperpolarization(K+ channels open) ⇒ Inhibition ⇒ Produce slower heart rate Depolarization(K+ channels closed) ⇒ Excitation ⇒ Cause smooth muscle of the digestive tract to contract
What type of tissue is the olfactory sensor cells? What are the different cells of the epithelium?
Olfactory neurons (receptor) -One dendrite projects to apical side with terminal know containing cilia -Olfaction receptors in membrane of cilia -380 functional genes that code for 380 different olfactory receptors proteins -One receptor cell = one type of olfactory receptor -Signaling of the cells is specific to one molecule Olfactory Epithelium 3 cell: 1) Receptor cell (Bipolar neuron) 2) Sustentacular cells (Supporting cell) -Oxidizes hydrophobic molecules limiting there permeability to plasma membrane 3) Basal cells -Stem cells (one site of neural stem cells) -Receptor cells replaced every 1-2 months
What are the structures for hearing in the inner ear?
Organs of Corti (Spiral Organ) Hair cells -Basal side located at basilar membrane -Stereocilia project into endolymph of cochlear duct (NO Kinocilia) -Inner hair cells: Mechanosensors -Outer hair cells: Innervated by motor neurons -Tectorial membrane: Hair cells embedded
What is the flow of signal after a photoreceptor is stimulated?
Pathway of light: Neural layer(Ganglion cells, Bipolar cells, Photoreceptors) ⇒ Pigmented layer Pathway of signal output: Photoreceptors⇒ Bipolar cells ⇒Bipolar synapse with the ganglion cells ⇒ Ganglion cells axons ⇒ Optic tract
What is the arrangement of the taste buds and how does the neural information flow?
Receptors are called taste buds-consist of 50 to 100 specialized modified epithelial cells with long microvilli that extend out through the pore in the taste bud to the environment of the mouth
What kind of the tissue are the sensory receptors for gustation?
Specialized epithelial cells 1) Cells behave like neurons by depolarizing and producing action potentials 2) Cells release neurotransmitters onto sensory neurons 3) Microvilli come into contact with chemicals 4) Each taste bud has taste cells sensitive to each category of tastes 5) But neurons stimulated only carry one kind of taste 6) tastes can be appetitive or aversive(嫌悪の) Taste buds -Located in bumps on the tongue called papillae -[Fungiform & Filliform]: Anterior surface -[Circumvallate]: Posterior surface -[Foliate]: Side
What are the two divisions of autonomic nervous system? What do these divisions control?
Sympathetic: Fight-or-flight Parasympathetic: Rest-and-digest
How does the autonomic differ from the somatic nervous system?
Target tissue Table 9.1
What is the major relay station for sensory information going to the cerebral cortex?
Thalamus -Afferent signals from senses(EXCEPT olfaction) converge on the thalamus -Any part of the brain that communicates with the cerebral cortex relays through a nucleus in the thalamus -Edits information sent to cerebral cortex
What is the process of transforming real world energy into neural impulses?
Transduction
How do the utricle and saccule differ from the semicircular canals?
Utricle and Saccule [Macula] -Specialized epithelium with hair cells and supporting cells -Hair cells project into endolymph and are embedded in Otolithic membrane -Otolithic membrane contains crystals of calcium carbonate increasing mass of membrane (resistance to change in movement) Semicircular Canal -Semicircular canals contains 4 ducts lying different planes (90 Degrees from each) -[Ampulla]: Base of each duct has a swelling -In ampulla, crista ampullaris contains sensory hair cells Cupula: gelatinous membrane containing hair cells -Cupula can be pushed in direction of endolymph movement -Endolymph movement will bend cupula depolarizing hair cells in the correct plane -K+ channels
What are the structures for equilibrium? What kind of information are stimulus for them?
Vestibular Apparatus 1) Linear acceleration [Utricle]: Horizontal acceleration, Forward & Backward [Saccule]: Vertical acceleration, Up & Down 2) [Semicircular canals]: Rotational (angular) acceleration [Superior(Anterior)]: Somersault(でんぐり返し) [Lateral]: Spinning on long axis [Posterior]: Cartwheel(側方転回)
What are the two regions of the adrenal gland? Which is involved in sympathetic NS? What makes this arrangement different from typical pathway in sympathetic NS and what is released from here and by what cells (name)?
[Adrenal Cortex]: The outer portion; a true endocrine gland of origin (mesoderm); secrete steroid hormones [Adrenal Medulla]: The small core; same embryonic tissue as sympathetic neurons (ectoderm); neurosecretory structure; modified sympathetic ganglion -The adrenal medulla is a specialized neuroendocrine tissue associated with the sympathetic branches -A modified sympathetic ganglion -Preganglionic neurons project from the spinal cord to the adrenal medulla -Postganglionic cells (chromaffin cells): lack axons, secrete epinephrine directly into the blood -The adrenal medulla releases large amount of epinephrine for general distribution throughout the body
How do tonic and antagonistic control differ? How does tonic control operate to change response at target tissue?
[Antagonistic control] -Most of the internal organs are under antagonistic control -One-autonomic branch is excitatory and the other branch is inhibitory [Tonic control] -Some tissue (the sweat gland and the smooth muscle in most blood vessels) are innervated only by the sympathetic branch
What type of receptor is each of the special senses?
[Chemoreceptors] detect the presence of chemicals. [Thermoreceptors] detect changes in temperature. [Mechanoreceptors] detect mechanical forces. [Photoreceptors] detect light during vision. More specific examples of sensory receptors are baroreceptors, propioceptors, hygroreceptors, and osmoreceptors
What parts of the eye refracts light? Which causes the greatest refraction and which can be changed to adjust the refraction of light?
[Cornea]: Majority of bending -Does not change shape [Lens]: Some of the bending -Can adjust bending -Autonomic innervation [Humors]: Very little bending
What does metabotropic and ionotropic receptors mean?
[Ionotropic receptors] such as nicotinic acetylcholine are a group of transmembrane ion channels that open or close in response to the binding of a chemical messenger. [Metabotropic receptor] are a type of G protein -coupled receptor When a metabotropic receptor is activated, a series of intracellular events are triggered that can also result in ion channels opening but must involve a range of second messenger chemicals.
What are the differences between nicotinic and muscarinic receptors?
[Nicotinic ACh receptors] ACh is excitory at nicotinic adrenergic receptor (chemical gated ion channel for sodium and potassium ions greater conductance of sodium ions so depolarizing [Muscarinic ACh receptors] Depending on receptor subtype ACh can be either excitatory or inhibitory at muscarinic cholinergic receptor (G-protein coupled receptor)
What are the different functions for the different structures of outer, middle, and inner ear?
[Outer Ear] -Auricle: Funnels the sound waves -External acoustic meatus: Channels the sound -Tympanic membrane: Produces movement from sound waves [Middle Ear] -Between tympanic membrane and oval window of cochlea -Ossicles ・Maleus: Hammer ・Incus: Anvil ・Stapes: Stirrup -Amplify sound waves from tympanic membrane: Large to small surface [Inner Ear] Cochlea -Scala vestibuli: Bony labyrinth(Perilymph) -Cochlear duct: Membranous labyrinth(Endolymph) -Scala tympani: Bony labyrinth(Perilymph) Coils to make three turns
What are the 5 different tastes and how do the cells signal for each taste (mechanism and what chemicals stimulate)?
[Salty] 1) Na+ passes into receptor channel in apical membrane 2) Depolarizes cell 3) Cause open the Ca2+ channels 4) Cause release of neurotransmitter to associated sensory neuron [Sour] 1) H+(Protons) in through receptor channel 2) Depolarization of the cell 3) Cause open the Ca2+ channels in the gustatory cell 4) Release of neurotransmitter to associated sensory neuron [Sweet/ Umami(meaty)] Activates G-protein receptor associated with taste - Gustducins -Sweet receptors have multiple ligand binding sites for multiple organic molecules (Monosaccharides) -Umami receptors bind to L-glutamate (Amino acids) or L-aspartate (present in protein) -Binding of different molecules can elicit(誘い出す) different second messenger pathways (Closed potassium channel) -Cause depolarization [Bitter] -Receptors have affinity(類似性) for multiple toxic compounds(Quinine) 1) Binding of receptor activates second messenger pathway 2) Cause opening Ca2+ channels inside of the endoplasmic reticulum 3) Cause releasing neurotransmitter
What are the different touch and pressure receptors and what do they respond to?
[Touch] -Free nerve ending(light touch), Around hair follicles: throughout skin -Merkel's discs(Sustained touch), Base of epidermis(stratum basale) [Pressure] -Pacinian corpuscles, Deep in dermis
What is the main parasympathetic tract? What does it innervate?
[Vagus Nerve] -The cranial nerve X -The major parasympathetic tract -Parasympathetic innervation goes primarily to the head, neck, and internal organs -Carry both sensory information from the internal organs to the brain and the parasympathetic output (motor) from the brain to organs
What are generator potentials? Would a bigger stimulus create a greater generator potential?
stationary depolarization of a receptor that occurs in response to a stimulus and is graded according to its intensity and that results in an action potential when the appropriate threshold is reached Yes. Higher frequency