anatomy physiology

Lab7_SpineReflexN1.docx

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Hands On Lab: Spinal Cord and Reflexes (7 Activities) Part 2

Submission instructions

Type your answers and copy all pictures directly into this Word document. Submit it via the blackboard submission link in Word format (docx).

Introduction:

You will complete a series of activities to help you better understand how messages are transmitted via our brain and spinal cord to our peripheral nervous system. You will be identifying structures of the nervous system and parts of the reflex arc. After you feel comfortable with identifying the foundations of the spinal cord and reflexes, you will perform some experiments applying this knowledge!

Watch These:

Patellar Reflex Animation(link opens in new window): This short ~30 second video, has a nice animation of the patellar reflex which will aid you in Activity 5

Crash Course Peripheral Nervous System (link opens in new window: 10 min). Crash course has several videos on the nervous system so if you find Crash Course helpful, check them out! This video applies directly to the content in this lab.

Activity 1: Divisions of the Nervous System

Identify the divisions of the nervous system (A-G). Each letter will only be used once.

1. Central nervous system (CNS) _____

2. Peripheral nervous system (PNS) ___

3. Somatic

4. Autonomic

5. Enteric

6. Sympathetic

7. Parasympathetic

A. Rest and digest

B. Voluntary

C. Brain and spinal cord

D. Brain of the gut

E. Involuntary

F. Fight or flight

G. Nerves and ganglia

Activity 2: Nervous Tissue

Nervous tissue consists of 2 main groups of cells, neurons and neuroglia. Neurons conduct electrical impulses while neuroglia provide support. This support can include, but is not limited to: neuronal insulation, immunity, protection, nutrient access, and waste disposal. Neurons, on the other hand, are largely classified by the number of processes per cell. Therefore, both neurons and neuroglia can be classified by their structure and function.

Use the terms provided to differentiate neurons and neuroglia in the table below. Each term will only be used once.

Word Bank: Satellite Cell, Microglia, Pseudounipolar, Schwann Cells, Ependymal Cells, Astrocytes, Multipolar, Bipolar, Oligodrendrocytes

Description	Term	Description	Term
Phagocytizes microorganisms and nervous tissue debris	8.	Lines brain ventricles. Aids in circulation of cerebrospinal fluid	13.
Supports neurons, numerous. Located in the CNS	9.	Supports and surrounds the cell body. Located in the PNS	14.
Produces myelin in the CNS	10.	Has one axon and one dendrite	15.
Single cell process. Appears to have axon and no dendrites	11.	Myelinates the axons of the PNS.	16.
Has one axon and multiple dendrites	12.

Activity 3: Organization of Spinal Nerves

Identify the spinal nerves and plexuses (A-K). Each letter will only be used once.

17. Lumbo-sacral plexus

18. Cervical nerves

19. Cauda equina

20. Lumbar nerves

21. Coccygeal nerves

22. Sacral plexus

23. Brachial plexus

24. Thoracic nerves

25. Lumbar plexus

26. Sacral nerves

27. Cervical plexus_______

Activity 4: Meninges

Several connective tissue membranes called meninges surround the spinal cord and brain. Between these are spaces that contain fluid, fat, or other substances.

Put the structures in order from superficial (1) to deep (8): Review the directional terms ‘superficial’ and ‘deep’ if you are unsure of what they mean.

1 has been given as a starting point. Remember, the vertebral column surrounds the spinal cord. Your spinal cord is running through the vertebral foramen (opening). If you are dissecting into the spinal cord, what layer is first after you go past the vertebrae? That is #2.

28. Subdural space

29. Subarachnoid space __

30. Dura mater _

31. Pia mater

32. Vertebrae __1___

33. Arachnoid mater

34. Spinal cord

35. Epidural space_____

Activity 5: Spinal Cord Cross Section Labeling

The spinal cord is the major relay center to and from the body and brain. It has sections of both white matter (myelinated axons for sending) and gray matter (cell bodies, dendrites, etc.—basically “thinking matter”). It is connected to the spinal nerves for transmission. Take note of the labels on the diagram, posterior and anterior.

Label the spinal cord (A-J). Each letter will only be used once.

36. Posterior gray horn

37. Dorsal white column

38. Anterior gray horn

39. Lateral gray horn

40. Central canal

41. Ventral white column

42. Lateral white column

43. Posterior root

44. Posterior root ganglion

45. Anterior root

Activity 6: Parts of a Reflex Arc

Using the diagram above to guide you, complete the chart below by adding in the parts and functions of a typical reflex arc. Here, you are thinking about the order and pathway a message travels in the body to enable responses to our internal and external environment. Some have been filled in for you.

Number	Function
46. #1	50.
47. #2	Carries sensory impulse to the spinal cord
#3 Interneuron	51.
48. #4	52.
49. #5	Area of body that carries out a response to cancel the stimuli (usually a muscle or a gland)

Activity 7: Reaction Time

Introduction

You will be performing 3 experimental tests below and answering questions. Reaction time is a measure how quickly organism responds to a stimulus. Reflexes and reactions, while seeming similar, are quite different. Reflexes are involuntary, used to protect the body, and are faster than a reaction. Reflexes are usually a negative feedback loop and act to help return the body to its normal functioning stability, or homeostasis. Reactions are actually a symphony of hundreds of thousands of neurons working together to produce a conscious decision. We have to decide what we would like to do regarding this stimulus. Furthermore, the quickness of reaction times can differ depending on what type of stimulus you are reacting to and what kind of task you are doing.

Test 1- Visual Response

Procedures:

1. You will need one 12-inch ruler (that can read cm) to complete this test.

2. Have your subject sit at a table with their dominant hand over the edge.

3. Hold the ruler at the 30 cm mark so that the 0 cm end is just at your subject’s index finger.

4. Tell your subject that when you release the ruler, they are to grab it as fast as possible.

a. DO NOT MAKE ANY SOUNDS OR GESTURES THAT INDICATE WHEN YOU WILL DROP IT!

b. They will need to only react to the visual stimulus of seeing the ruler being released.

5. Record the cm mark above the index finger in the chart below.

**Record all results for tests 1-3 in the table located below test 3**

6. Repeat the experiment 3 more times.

7. Switch with your subject and you do the visual only catch 4 times as well.

Test 2- Auditory Response

Procedures:

1. Have your subject sit back at a table as they did during the first test. We will still be using the dominant hand

2. Blindfold your subject.

3. Tell the subject that you will say “RELEASE” as you release the ruler.

4. Once they grab it, record the centimeter mark and repeat 3 times.

5. Switch with your subject and complete 4 times

Test 3- Tactile Responses

1. Have your subject sit back at the table with their dominant hand once again over the edge.

2. Blind fold subject again.

3. Tell the subject that you will touch the shoulder of their non-dominant arm as you release the ruler.

a. Give NO AUDITORY CUES- SIMPLY TOUCH

4. Record the centimeter mark and repeat 3 times

5. Switch with your subject and complete 4 times.

53. Complete the table with UNITS (cm and sec as needed)

	Visual (cm)	Auditory (cm)	Tactile (cm)
	1.	1.	1.
Subject	2.	2.	2.
1	3.	3.	3.
	4.	4.	4.
Average (cm)
Reaction time (sec)
	1.	1.	1.
Subject	2.	2.	2.
2	3.	3.	3.
	4.	4.	4.
Average (cm)
Reaction time (sec)

Average distance (cm)	Reaction time (sec)
1	0.045
2	0.064
3	0.078
4	0.090
5	0.101
6	0.111
7	0.120
8	0.128
9	0.136
10	0.143
11	0.150
12	0.156

To determine your reaction time, use the table above.

Conclusion Questions

Insert 2 pictures of you and your subject completing the activity.

Answer the Questions Below:

54. The average reaction time for humans is 0.25 seconds for a visual stimulus, 0.17 for an audio stimulus, and 0.15 seconds for a touch stimulus. With this information in mind, which of your senses had the fastest reaction time?

55. Why do you believe this is?

56. A variety of factors may impact tactile reaction time. Some studies have indicated that higher levels of education correlate with faster responses. This may be attributed to an elevated information processing speed. Also, routine movements have been positively correlated with reaction time. For example, right-handed people respond faster with their right hand when using a right-handed computer mouse . With this information in mind, how do your results compare with the nationwide average (approximately 0.15 seconds)?