Answer:
The answer to the question: Electrical impulses or action potentials (AP) cannot propagate across a synaptic cleft. Instead, neurotransmitters are used to communicate at the synapse, and re-restablish the AP in the post-synaptic cell, would be, true.
Explanation:
Essentially, although the CNS, PNS and ANS (Central Nervous System, Peripheral Nervous System and Autonomic Nervous System) are electrical systems, that use the electricity generated through action potentials, that in turn, are created by the exchange of electrically charged ions from within and without the neuronal cells, these electrical impulses do not pass the pre-synaptic, and post-synaptic cleft. Instead, once an AP has reached the terminal end of the pre-synaptic neuron, neurotransmitters are released by this one, into the cleft, which are then taken up by the receptors present in the post-synaptic neuron. Depending on the type of transmitter released, there will be an inhibitory or excitatory effect. Then, with the transmitter attached, the post-synaptic neuron will depolarize and a new AP will be generated in the post-synaptic neuron, which will carry on. Messages, thus are transmitted that way between neurons, and also, between the nervous system and the organs they influence.
Answer: The cornea is avascular.
Explanation:
The cornea can be defined as the clear front membrane on the surface of eyeball. It lies in the front of the iris and pupil. It allows the light to enter the eye. A cornea transplant is recommended in patients who suffer from vision problems due to thinning of cornea, keratoconus, loss of vision and cloudiness of cornea.
It takes about 2 to 3 months to recover after surgery. The healing is slow because the cornea is avascular. The tissue of cornea does not provide blood vessels to deliver nutrients and oxygen which could aid in speedy recovery.
Answer: Option D. "Heme"
Explanation:
Deoxyhemoglobin can be defined as a form of which has no oxygen binded to the hemoglobin.
When deoxyhemoglobin is replaced with oxyhemoglobin then the oxygen binds to the heme component of the hemoglobin protein in red blood cells.
Each heme group has iron atom that has the ability to bind to oxygen (02) molecule.
Four oxygen molecules bind to a single hemoglobin protein.
Hence, the correct answer is option D "Heme".
99201 requires 3 components, a problem focused history, a problems focus examination and a straight forward medical decision.
