A 25-year-old preschool teacher, Sandy Thompson, has not been
feeling like herself lately. She has been feeling quite tired and
her co-workers have commented on her droopy eyelids. Additionally,
she is experiencing weakness in her arms and legs, has difficulty
talking clearly and even her students’ parents have been concerned
that Sandy hasn’t been looking very happy at work. One day at
lunch, Sandy started to choke on her food, causing one of her
coworkers to perform the Heimlich maneuver on her. While the scare
didn’t cause any permanent damage, Sandy is convinced that it is
time to go see a doctor.
When she finally arrives at her appointment with Dr. Wayne,
she explains to Dr. Wayne what has been going on, and the doctor
decides to run a few blood tests. Sandy’s blood work results are
presented below.
S. Thompson – Test Results
NATIONAL CENTER FOR CASE STUDY TEACHING IN SCIENCE
Test
Result
Normal Range
Blood Pressure
115/73
90-120/60-80
Hematocrit (%)
36.5
36-38
Glucose (mg/dl)
94
70-110
Sodium (mmol/L)
144
135-145
Potassium (mmol/L)
4.3
3.5-5.0
AChE Activity Test (%)
100
100
Tetraiodothyronine or thyroxine ( T4) (ng/dL)
11.3
4.6–12
Serum Triiodothyronine (T3) (ng/dl)
154
80–180
Antibodies for ACh Receptors
Present
Not Present
Questions
1. What symptoms is she experiencing?
2. What levels from her blood work are abnormal?
3. How would antibodies against ACh receptors affect the
neuromuscular junction?
4. How would antibodies against the ACh receptors affect the
influx of Na+ into the cell?
“All or Nothing” by Neumann, Quinn, Whitaker, Woyton, &
Harris
Page 5
NATIONAL CENTER FOR CASE STUDY TEACHING IN SCIENCE 5. How
would antibodies against the ACh receptors affect the levels of
Ca2+ inside the sarcoplasmic reticulum?
What effect does this have on the actin and myosin
filaments?
6. What disorder does Sandy have? How do we treat/manage this
diagnosis?
Look over the data on and identify which areas are out of the
normal range and answer the following questions for that
item.
1. What type of molecule is it?
2. What is its normal function/role?
3. How might it be connected to Sandy’s symptoms? Explain in
detail. (Why would it be causing these symptoms physiologically?
What is the impact on the NMJ?) Consider the following items in
your answer.
1. Antibodies
2. ACh receptors
3. Calcium ions
4. Sarcoplasmic reticulum
5. Sodium ion channels
6. Membrane potential
7. Myosin
8. Actin
9. Troponin
10. Acetylcholine
11. T-tubules
12. ATP
13. Pre-synaptic neuron(s)
14. Post-synaptic muscle fiber