BSCI 207 Lecture Notes - Lecture 30: Olfactory Receptor, Electrochemical Gradient, Membrane Potential

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amaranthllama268

14 Nov 2016

School

University of Maryland

Department

Biological Sciences Program

Course

BSCI 207

Professor

Dr.Karen/ Dr.Hagg

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Document Summary

Hair cells in ear and skin, photoreceptors, olfactory receptor, taste buds and more. Sensory cells receive signals and convert it into a neural output: neural output is proportional to the magnitude of the input. Not all sensory neurons send action potentials: hearing and vision neurons do not send action potentials, these neurons lack voltage gated ion channels, still have calcium ion channels to release neurotransmitters. Instead, stimulus results in a proportional change in membrane potential: resting state of a sensory neuron may still result in the release of neurotransmitter, this proportional change increases sensitivity and resolution of the associated sense. If the receptor cell does not make action potentials, the post-synaptic neuron will make one. Receptors and ion channels are coupled in different ways. Ionotropic: the ion channel is the receptor itself. It is opened by mechanical pressure or by binding a ligand. Metabotropic: the stimulus binds to the receptor molecule and actuates a g protein.

Related Questions

Sensory systems

1.All sensory input arrives at the central nervous system in the same form, as ____________ propagated by afferent neurons. Perception of the type and intensity of a stimulus depends on which part of the brain the impulse projects to and the firing frequency the sensory neuron.

A.action potentials B.receptor potentials C.reflexes D.frequency localizations E.thresholds

2.The simplest sensory receptors are __________ that respond to mechanical distortion,changes in temperature, or specific chemicals.

A.nociceptors B.free nerve endings C.gated channels D.photoreceptors. E.ganglia

3.When membrane proteins on an olfactory neuron are stimulated by the binding of a specific chemical, what is the immediate result?

A.membrane depolarization B.membrane repolarization C.active ion transport D.membrane hyperpolarization E.neurotransmitter release

5.The lateral line system provides ________ with a sense of "distant touch," enabling these animals to sense objects that reflect pressure waves and low-frequency vibrations.

A.adult amphibians B.reptiles C.birds D.mammals E.fish

6.Which correctly represents the sequence of steps involved to convey sensory information to the CNS?

A.stimulation and ion flow through the synaptic cleft B.neurotransmitter release and interpretation
C.neurotransmitter release and ion flow through the synaptic cleft D.stimulation, transduction, transmission, and interpretation E.stimulation, transmission, and neurotransmitter release

7.Which of the following stimuli do vertebrates NOT have a specialized receptor for?

A.hearing B.taste C.smell D.humidity E.vision

8.Which of the following is NOT an example of a mechanoreceptor?

A.Meissner's corpuscles B.Ruffini endings C.Merkel cells D.red corpuscles E.Pacinian corpuscles

9.What are the receptors called that transmit impulses that are perceived by the brain as pain?
A. baroreceptors B. chemoreceptors C. nociceptors
D. thermoreceptors E. propioceptors

10. Which of the following do humans NOT have taste buds specialized to sense?

A. salty B. sour. C. sweet. D. vitamins E. bitter

11.Which sequence of events is required for the brain to interpret sound?
I. Vibration of the basilar membrane relative to the tectorial membrane causes cilia on hair cells to bend and triggers depolarization.

II. Hair cells stimulate the production of action potentials in sensory neurons that project to the brain.

III. Ganglion cell axons transmit action potentials to the occipital lobe.

A. II then I B.III then I then II. C.III then I D.I then II E.I then II then III

12. Which animal became numerous and widespread by using sonar to enable a high level activity in the dark?

A.bats B.whales C.owls D.dolphins E.shrews

13.In the vertebrate eye, what structure is light focused onto?

A.pupil B.lens C.retina D.sclera E.iris

14.Which is NOT a part of the vertebrate eye?

A. cornea B. retina C. iris D. cochlea E. pupil

15. In the vertebrate eye, what structure controls the amount of light that reaches the retina?
A. fovea. B. cornea. C. iris D. lens E. sclera

16.What are the short retinal photoreceptors responsible for color vision called?

A.rods B.cones C.bipolar cells. D.glial cells. E.ganglion cells

17. What sensory equipment is required for an animal to have binocular vision?

A.eyes located to the sides of the head B.forward-facing eyes C.a camera-type eye with multiple lenses

D. infrared vision E.ultraviolet vision

18. Choose the receptor that is NOT correctly matched with its function.

A.proprioceptor - monitors stretch of muscle fibers

B.baroreceptor - monitors hydrostatic pressure in blood vessels

C.nociceptor - transmits signals that the brain interprets as pain

D.chemoreceptor - perceives taste and smell stimuli

E.peripheral chemoreceptor - monitors the pH of the cerebrospinal fluid

19. Where is the visual image in focus for a nearsighted individual?

A.behind the retina B.in front of the retina C.on the retina, but it appears blurred

D.at the lens, forming a shadow on the retina E.on the retina, but it is upside down

20. Since the optic nerve must pass through the retinal layer, we all have a blind spot devoid of light receptors. This normally goes unnoticed, since the brain attempts to compensate for missing sensory information by filling it in based on surrounding patterns. Which step of the sensory pathway is represented by perceptual filling-in of the physiological blind spot?

A. interpretation B. stimulus. C. transduction into receptor potential D.action potential transmission

Santiago Ramon y Cajalâs theory of dynamic polarization refers to the:

(a)membrane potential of a neuron at rest.

(b)membrane potential of a neuron firing action potentials.

(c)opening and closing of gated channels in the membrane.

(d)one way flow of information in neurons from dendrites to axon terminals.

(e)one way flow of information in neurons from axon terminals to dendrites.

Over the course of scientific history, there are many examples of scientists reaching the right conclusion for the wrong reasons. When Schwann first proposed that the nervous system was made of individual cells, he based it on observations of:

(a)synapses.

(b)dendrites

(c)axon terminals.

(d)astrocytes.

(e)Nodes of Ranvier.

The synaptic cleft was finally seen in the 1950s. What prevented scientists from seeing it earlier?

(a)The resolution of the light microscope.

(b)They were looking in the wrong place.

(c)Their tissue was not appropriately stained.

(d)Myelination of the axons.

(e)all of the above

The resting membrane potential of a neuron is approximately:

(a) +65 V

(b) +65 mV

(d) -65 mV

What is largely responsible for the resting membrane potential in a neuron?

(a)Axonal insulation by myelin

(b)Voltage-Gated Sodium Channels

(c)The Action Potential

(d)Potassium Leak Channels

Which of the following would DECREASE the propagation velocity of an action potential down an axon?

(a)Increase in axon diameter

(b)Increase myelination between nodes of Ranvier

(c)Remove myelination between nodes of Ranvier

(d)Decrease density of voltage-gated Na+ channels except at the Nodes of Ranvier

The resting membrane potential of a neuron can be estimated using the:

(a)Nernst equation

(b)Goldman equation

(c)Hodgkin and Huxley equation

(d)Ohmâs law

18. What would happen to the resting membrane potential of a neuron if you added K+ to the extracellular fluid?

(a)Resting membrane potential would increase (become more positive)

(b)Resting membrane potential would decrease (become more negative)

(c)Resting membrane potential would not change

(d)Resting membrane potential would be abolished

. Which of the following statements is FALSE for Graded Potentials

(a)Magnitude changes with magnitude of triggering stimulus

(b)Magnitude decreases with distance from initial site

(c)Cannot be summed

(d)No refractory period

In the nervous system, the strength of the stimulus is coded into:

(a)The frequency of action potentials generated

(b)The amplitude of action potentials generated

(c)Both the frequency and amplitude of action potentials generated

(d)The duration of individual action potentials generated

Ion movement during both the depolarization and repolarization phases of an action potential are the result of:

(a)active transport pumps along the neuron membrane.

(b)diffusion of ions down their electrochemical concentration gradients.

(c)negative feedback loops.

(d)All of the above

At the peak of the action potential, the membrane potential is:

(a)Exactly at the Na+ equilibrium potential

(b)Greater (more positive) than the Na+ equilibrium potential

(c)Above 0 mV but less positive than the Na+ equilibrium potential

(d)0 mV

BSCI 207 Lecture Notes - Lecture 30: Olfactory Receptor, Electrochemical Gradient, Membrane Potential

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