1

General A&P Nervous Tissues, Nerves, Spinal Cord and Reflexes #1

Pre-Lab Exercises Have someone in your group read the following out loud, while the others read along:

In this "Pre-lab Guide", we will be looking at Nervous Tissues, Nerves, Spinal Cord and Reflexes. This should be done before lab, so we don't waste time in lab! This guide should only be attempted after reading the correct sections in either the lab or lecture book, or watching any videos that have been assigned. We will have several weeks of labs covering the Nervous System. During that time, we will be covering these topics:

1. Nervous System Cells 2. Basics of Nervous Tissues 3. Structure & Function of the Spinal Cord and Spinal Nerves 4. Basic Reflex Anatomy & Physiology 5. Structure & Function of the Brain & Cranial Nerves 6. Eye Anatomy & Vision Tests 7. Ear Anatomy

During this first week of labs, we will be covering topics 1-4 on the list. These are found in more than one lab in your lab book:

1. Nervous System Cells 2. Basics of Nervous Tissues 3. Structure & Function of the Spinal Cord and Spinal Nerves 4. Basic Reflex Anatomy & Physiology

You should only do these exercises after doing your assigned reading or watching the online videos.

2

#1

Step 1. Introduction to the Nervous System Chapter: Review Key Concepts from the book and videos Have someone in your group read this, while the others follow along:

Introductory Paragraph (we will be referring to this later):

Lab books and text books often begin the discussion by going over some basic concepts of nervous cells & tissues. You may use either lab or lecture book to define the following terms, or answer the question. Keep each definition short. USE A SEPARATE PIECE OF PAPER if you need more space:

Q1. Define Neuron: Q2. Define Neuroglial (glial) cell : Q3. Define Synapse:

Read Me

3

Q4. Define Myelin: Q5. What is the difference between the CNS & PNS? Q6. What is the difference between saying "neuron" and "nerve"?

4 #2 ID the parts of a neuron.

Instructors differ in which parts of a neuron you need to know. However, most have you begin with some basic parts.

Q7. The image below is showing a motor neuron that has its body dissected, so you can see the contents. Label the following on the image:

Body/Soma Mitochondria Dendrites Nucleus Axon Myelin sheath Axon hillock Nodes of Ranvier

Teleodendrites or teleodendritic region

Read Me

5

#2 Functional versus Structural Classification of Neurons. There are 2 ways to classify any neuron: what they do (Functional classification) and how they look (Structural classification). This is similar to saying that there are 2 ways to classify any building: what they do, or functional classification ("house" versus "barn" versus "office building") and their architectural design or structural classification ("contemporary" versus "traditional" versus "Spanish-style"). So...a building can be classified using both systems! You can have: "contemporary house" versus "contemporary office building", and your can have a "contemporary house" versus "Spanish-style house"

Q8. What are the functional classifications of neurons you need to know for lab? Label them on this drawing, placing the correct number inside each box: Q9. What are the synonyms for:

Afferent neuron: Efferent neuron:

Read Me

Aloud!

6 Q10. What are the structural classifications of neurons you need to know for lab? Label them on this crude drawing, looking up the correct terms in your book

Although structural and functional classifications are different ways to look at the same neuron, there is a relationship between the two classification systems:

Q11. Fill in the blanks using "structural category" terms:

"All sensory (afferent) neurons are ______________________ neurons, while all motor (efferent) neurons are _______________________ neurons."

Q12. Label which of these neurons might be a "sensory" or "afferent" neuron. Which might be a "motor" or "efferent" neuron?

Read Me

7 #3 ID the parts of a neuron on a slide.

Instructors differ in which parts of a neuron you need to know off a slide. However, most have you begin with some basic parts. Note that it is difficult to distinguish an axon from a dendrite, so here we will not worry about the axon. Your instructor will show you how to tell them apart in lab if you need to be able to distinguish them on an exam.

Q13. The image below is showing a motor neuron slide. In the room, there is a microscope witha neuron slide. Find the following terms on the slide, and label the following on the image:

Body/Soma Dendrites Glial cells Nucleus of neuron Satellite Cells

Read Me

8 #4 ID the parts of a nerve.

Q14. Look at the image below. Use the numbers on the image to identify the following, putting the correct number in the blank. If you do not know one, skip it and come back after you've done the others:

An individual neuron ______ The axon of a neuron ______ The myelin sheath around the axon _______ The Nodes of Ranvier between the myelin sheaths _______ The endoneurium, or protective covering around a neuron _______ A bundle of neurons, or fasciculus _______ The perineurium, or protective sheath around the fasciculus _______ The entire nerve _______ The endoneurium, or protective covering around a nerve_______

9 #5 ID and label the parts of the "Spinal nerves and spinal cord" model

Q15. Identify the parts of the spinal cord and spinal nerve image below:

1. ______________________ 6. ______________________ 2. ______________________ 7. ______________________ 3. ______________________ 8. ______________________ 4. ______________________ 9. ______________________ 5. ______________________ 10. ______________________ Q16. What is I filled with? ________________

10 Q16. Find an image of a transverse vertebra, like the one pictured below. Find all the structures you need to know, including (but not limited to): Everything you found in the previous question! Plus: All the meninges All the spaces between the meninges Any structures of the white and gray matter that you need to know All the structures of the spinal nerves and roots that you need to know. Label the image below as a key for later study.

11 #6 Look at the "Spinal Cord - Transverse Section" slide.

Notice that you are seeing a cross section that looks a lot like the image from Question 15:

Q17. Label the photo of a slide below, indicating everything you labeled in Question 15:

Try This!!

Read Me

slide image

12

#7 Answer some questions about the spinal cord and spinal nerves.

Answers these based on your readings, or any video you've watched. Q 18. How many regions or curves of the spinal cord are there? Label them on the image labeled "A" below. Include the number of vertebrae in each region. Q 19. How many types of spinal nerves are there? Label them on the image labeled "B" below. Q 20. How many of each type of spinal nerves are there? Write your answers on image "B" below.

Read Me

Image A

Image B

13

Q 22. Circle & Label the plexi on the diagram below. Q 23. Which type of spinal nerve does not enter a plexus? HINT: should be one of your answers to Question 20.

Q 24. Label the nerves indicated in your lab book.

14

#8 The second is a model of the vertebral column, Study the Reflexes.

Reflexes can be categorized in several ways. We will first divide them based on the effectors .... that is, somatic (skeletal muscle) versus autonomic (all others...gland, smooth muscle, etc.). Here is a categorization system commonly used:

1. Somatic Reflexes (all control skeletal muscle)

a. Spinal reflexes i. Stretch (example: Patellar) ii. Superficial (examples: Plantar) iii. Special cases: (example: Babinski’s sign)

b. Cranial i. Corneal ii. Gag

2. Autonomic Reflexes: control smooth muscle or glands

* Examples in lab book: papillary reflex

Another categorization system looks at where the response is:

Q 25. In the space below, define the terms contralateral and ipsilateral

In lab, you will be responsible for describing the reflex examinations described in your lab book, and knowing how to categorize them!

Read Me

Know this!

Important point!

15

Q. 26. Write down all the reflexes mentioned in your lab book, or on the videos. For each, write down whether it is somatic or autonomic. If it is somatic, write down if it is spinal or cranial, and then give the specific category.