Exercises 26 and 27

1
Exercises 26 and 27

• Spinal Cord and Meninges
• And Reflex Arc and Reflexes

2
Exercise 26- Meninges and Spinal Cord

• Objectives
• Name the layers of meninges and describe the
  structure
• Identify the major features of the spinal cord

3
Procedure A

• Using the spinal cord section available in class
  or pictures in your textbook, locate the
  following structures
• posterior median sulcus (just remember its PMS)
• anterior median fissure
• central canal
• gray matter (gray commissure, posterior horn,
  lateral horn, anterior horn)
• white matter (posterior funiculus, lateral
  funiculus, anterior funiculus)
• roots of spinal nerve (dorsal root, dorsal root
  ganglion, ventral root)

4
Procedure B

• http//www.wheelessonline.com/ortho/dural_membrane
  _of_the_spine
• http//training.seer.cancer.gov/module_anatomy/uni
  t5_3_nerve_org1_cns.html
• Identify the dura mater, arachnoid mater, and pia
  mater on figure 26.1
• Identify epidural space, subdural space, and
  subarachnoid space
• Which has CSF?

5
Links to help

• Go here for a web site on the spinal cord
• http//faculty.washington.edu/chudler/spinal.html
• Go here for a completed diagram of the spinal
  cord section
• http//www.becomehealthynow.com/popups/sp_section.
  htm
• or here http//www.1biology.50megs.com/transspin
  al.htm
• or here http//www.bio.psu.edu/faculty/strauss/ana
  tomy/nerv/spinal.htm
• Here is a word search game http//faculty.washin
  gton.edu/chudler/java/searchsc.html

6
Reflex Arc and Reflexes

• Exercise 27

7
Procedure-Reflex arc

• Demonstrate the reflexes listed in ex. 27 (follow
  directions in the lab manual).
• Patellar (Knee-Jerk) reflex-strike patellar
  ligament gently with percussion hammer just below
  patella. The leg should extend slightly
  (quadriceps reacts by contracting)
• Calcaneal (ankle-jerk) reflex- strike calcaneal
  tendon carefully with percussion hammer. Foot
  should plantar flex slightly.

8
More reflexes

• Biceps jerk reflex-press thumb on inside of elbow
  (bend arm) and use rubber hammer to gently strike
  the thumb. Biceps brachii should respond.
• Triceps jerk reflex- gently strike triceps
  brachii tendon just above the olecranon process
  and watch for response.
• Plantar reflexremove shoe, gently draw metal
  handle of percussion hammer along lateral surface
  of foot. Toes should curl. Babinski reflex is
  seen in babies (toes spread out)
• Fill out lab reports!