Human Anatomy and Physiology: Case Study Please help with all or most, really lo

Question

Human Anatomy and Physiology: Case Study

Please help with all or most, really lost and do not understand.

Before drilling on a patient’s tooth, a dentist typically gives the patient a shot of local anesthetic, such as procaine hydrochloride ( Novacain) or lidocaine (Xylocaine). The injection is given in the mouth near the location of nerves that innervate the particular tooth. When the anesthetic reaches the neurons, certain regions of the face, mouth and tongue lack sensation or become numb.

The drug works by blocking neurons communicating with the CNS. The brain is unaware of the presence of painful stimuli in the mouth.

Answer the following question concerning the mechanism of action for the numbing procedure.

The mechanism of action is due to the drug blocking the voltage-gated sodium channels in neurons.

4. Novacaine and other local anethetics work by blocking the voltage-gated sodium channels in sensory neurons. Explain what occurs if these channels are blocked. Does this drug cause a Graded potential (define) a EPSP an IPSP (define and answer) Does this drug affect the motor pathway as well? Explain ( 5 points)

5. Will a post synapse neuron be involved? Why? (3points)

2. Trace a sharp pain received in the right foot up the spinal cord to the cortex of the brain. ( 3 points) What white mater in the spinal cord will carry a signal from the right leg to cortex? (2 points) Where are the 1st, 2nd and 3rd order neurons located? (2 points) What hemisphere will receive the message? (2 points) Trace the descending pathway, name and locate the higher and lower motor neurons. (4 points)

Explanation / Answer

4. If the Novacaine or local anesthetis are administered then the sodium channels in the patient's brain gets blocked . This stops the propagation of the action potential.

The graded potential is produced when an ion opens up the ion gated channel. But this potential is not sufficient to produce a signal and it gets weakened as it moves farther from where it is produced.

Binding of local anesthetics causes blocking of action potential and hypolarises the membrane (IPSP).

Binding of anesthetics doesnot affect the motor pathway as it temporarily blocks the nerve impulse propagation. It doesnt cause unconsciousness.

5. Post synapse neuron cannot be involved because the action potential is not generated . So the message from one neuron to other cannot be passed down .

6.Myelinated axons carry signals to the brain.

Left hemisphere gets the message.

1.The first order sensory neurons are in the dorsal root ganglia of cranial nerves.
2. The second order sensory neurons are in the dorsal gray column of the brainstem.
3. The third order sensory neurons are in the thalamic nuclei.

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