Biology 8 Lesson 45: Spinal nerves
1. Summary of theory
1.1. Structure of spinal nerves
– From the spinal cord arise 31 pairs of spinal nerves.
– The spinal nerves communicate with the spinal cord through the anterior and posterior roots, which include afferent bundles (connecting to the spinal cord via the posterior root) and efferent bundles (connecting to the spinal cord via the anterior margin).
– The anterior root conducts motor impulses from the center to the responding organ (muscle extremities).
– Posterior roots transmit sensory nerve impulses from the receptors to the center.
1.2. Functions of spinal nerves
– Anterior roots conduct motor nerve impulses from the central nervous system to the response organs
– Posterior roots transmit sensory nerve impulses from the receptors to the central
– The spinal nerve is the pharyngeal nerve
2. Illustrated exercise
Please state the proposed steps in the experiment to detect the spinal roots related to the spinal nerves going to the hind limbs of the frog to see which roots are still present, which roots have been inserted when Quan opens the vertebral arches to Find the spinal roots to prepare for the teacher, she conducts the experiment “to learn about the function of the spinal nerves”?
What you know from the lesson:
The function of the white matter in the spinal cord is to connect the bases that control the lower extremities with the upper and vice versa.
Posterior roots are sensory roots, conduction of afferent impulses, and anterior margins are motor roots: conduction of centrifugal impulses.
Based on that understanding, we can propose experimental plans to find out which roots are still alive and which ones are lost for Quan before bringing them to class to see illustrations for the lesson.
Option 1: Stimulation of the following extremities, the following cases may occur:
a) Stimulating the right hind limb
None of the limbs are contracted —> conclusion: the posterior right hind limb is severed.
The right and left hind limbs are both contracted: the right posterior roots, both the anterior roots going to those two limbs are still there.
Only the right or left hind limb is contracted: the right posterior root is still there and which limb is there, indicating that the limb has an anterior root, but it is not known if the posterior root of the left limb is still there?
b) Stimulation of the left hind limb must be continued: If one of the limbs is still visible, it means that the left posterior root has not been severed.
c) If both hind limbs are stimulated, no limb contraction can only be concluded that the posterior roots have all been severed; so are the previous roots still broken? To know for sure, continue to step d.
d) Strongly stimulated forelimbs, pulses will be transmitted along the white matter down to the control bases of the hind limbs, if any side motor roots remain, that side’s limbs will contract.
Plan 2: Much simpler, just:
a) Stimulating the forelimbs very strongly, the hind limb on one side shows that the motor roots corresponding to that limb are still there and have not been severed.
b) Then, in turn, strongly stimulate the hind limbs to see which side of the posterior roots remain, which side is severed? If left, the frog will react, if broken, will not cause a reaction in the frog.
3.1. Essay exercises
Question 1: Why is the spinal nerve a phase cord?
Verse 2: On a frog that had been operated on to study the medullary roots, Quang unintentionally pushed the scissors to break some roots. How can I find out which roots are still alive and which ones are missing?
Question 3: Which sentence is correct put T and the wrong sentence put S in the blank:
3.2. Multiple choice exercises
Question 1: Why does herniated disc cause pain?
A. The bones collide with each other
B. Pinched nerve
C. Detected joint capsule
D. Nerves are twisted
Verse 2: Nerves are made of what?
A. Sensation Roots
B. Motor roots
C. Sensory nerve fiber bundle
D. Radial and centrifugal bundles
Question 3: Where do afferent nerve fibers conduct nerve impulses?
A. Information processing center
B. Sensory organs
C. Stimulus response organ
D. Centrifugal nerve
Verse 4: The sensory nerve fibers float with the spinal cord by which part?
A. Anterior Root
B. Posterior roots
C. Nerve ganglion
D. Featured Parts
Question 5: What function does the spinal nerve perform?
A. Conduction of nerve impulses
D. Information processing
– After completing the course, students will be able to:
- Nerve structure, spinal nerve function.
- Develop skills in observing and analyzing pictures.
- Train students in group work skills.