Hi, I have several questions that I am not sure or do not know their answers. Lecturer gave the key words but I think there are some questions that do not have any answer among those key words.
Please tell me whether the answer are correct or not. And tell If you have better answers
I am not sure the answers of these:
1) List at least 5 most striking morphological and functiolnal characteristics of nerve tissue make it different from other tissues.
***Answer: a) having dendrites and axon ; b) polarization; c) generate& transmit sigmanls btw environment and body; d) excitable ; e) not reproduce
2) Three gating mechanisms of the membrane ionophores (ion channels) are ______, ______ and ______.
***Answer: chemically gated channels, voltage gated channels and mechanically gated channels. (But there is "osmotic gradient" as one of answer. That's why I'm confused.)
3) The main differencce btw ionotropic and metabotropic receptor is _________.
*** Answer: chemical ligand
4) Integration of postsynaptic potentials depends on two passive properties of the neuron's membrane which are _________ and ___________.
*** Answer: length constant and time constant of the membrane.
5)The most sensitive sensory receptors are so called ________.
***Answer: hair cells
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AND I do not know answer of this question:
6) In the sensory systems, stimulus intensity is encoded by ______ while stimulus modality (quality) is encoded by ______.
1) Your answers for the most striking morphological and functional characteristics of nerve tissue are mostly correct, but there is room for improvement. Here are some suggestions:
a) Having dendrites and axons: This is correct as nerves have these specialized structures for both receiving and sending signals.
b) Polarization: Instead of just mentioning polarization, you can mention that nerve tissue has the ability to generate and maintain electrical potential differences across its membrane.
c) Generation and transmission of signals between environment and body: This is a good point, but you can further emphasize that nerve tissue is responsible for communication within the body and with the external environment.
d) Excitability: This is a good characteristic to mention, as nerve tissue is capable of being stimulated and generating electrical impulses.
e) Not reproducing: This is correct, as nerve tissue usually cannot regenerate or reproduce to replace damaged cells.
2) Your answer for the gating mechanisms of membrane ion channels is correct, but there are indeed more than three types. Here are some additional types of ion channel gating:
a) Ligand-gated channels: These channels open or close in response to the binding of chemical messengers (ligands) such as neurotransmitters.
b) Thermally-gated channels: These channels open or close based on changes in temperature.
c) Light-gated channels: These channels open or close in response to specific wavelengths of light.
Osmotic gradient, though related to ion movement, does not directly refer to the gating mechanisms of ion channels, so it's not a correct answer in this context.
3) The main difference between ionotropic and metabotropic receptors is not specifically related to a "chemical ligand," but rather the mechanism of activation and signal transduction. Here's a more accurate answer for this question:
The main difference between ionotropic and metabotropic receptors is the way they initiate signal transduction. Ionotropic receptors directly open or close ion channels in response to the binding of neurotransmitters, while metabotropic receptors indirectly affect ion channels, either through intracellular signaling pathways or by modulating the release of second messengers.
4) Your answer for the integration of postsynaptic potentials is correct. The two passive properties of the neuron's membrane that affect the integration of these potentials are the length constant and the time constant. The length constant determines how far a postsynaptic signal can propagate along the neuron's membrane, while the time constant influences the speed of signal integration and decay.
5) Hair cells are indeed one of the most sensitive sensory receptors, especially in the auditory system. They are responsible for detecting sound vibrations and converting them into electrical signals that can be interpreted by the brain.
6) In sensory systems, stimulus intensity is encoded by the frequency or rate of action potentials generated by sensory neurons. On the other hand, stimulus modality or quality is encoded by the specific sensory receptors activated and the corresponding neural pathways they stimulate in the brain.