Question

Leah, a 20-year-old woman, awakens one morning to a tingling, numb sensation covering both of her feet. This has happened to her a number of times throughout the year. In the past, when experiencing this sensation, within a couple of days to a week the numbness would subside, and so she is not too concerned. About a week later, she notices that the numbness and tingling not only persists, but has also spread up to her knees. Again, she ignores the abnormal sensation. By the end of a month’s time, the numbness spreads to the midline of her body. At this point, she becomes alarmed. Leah sees the nurse at her college who tells her that she should see a doctor. Leah calls her doctor’s office to schedule an appointment, but the soonest slot is in two weeks. She makes the appointment and goes about her daily routine. The next morning, Leah wakes, but when she attempts to get out of bed, she comes crashing to the floor. Because she is still groggy from sleep, she doesn’t really understand what has just happened. As she tries to stand up, the muscles of her left leg engage, but as she also attempts pushing up with her right leg, she again falls to the floor. She sits in bewilderment as she tries to make sense of what has just happened and realizes that she has seriously scraped her knee in her fall. She does not feel the pain from her wound.

Leah thinks about how odd this year has been. She remembers another medical issue she had earlier in the year when she had lost hearing in her right ear and wonders if there is a connection to her current condition. At that time, Leah underwent extensive testing, but the ear, nose, and throat specialist remained baffled. He thought that a severe inner ear infection could have destroyed her ability to hear on that side, but there was no conclusive evidence to support this. In an attempt to recover any hearing, he could, the doctor prescribed very high dosages of steroids; he told Leah that she probably wouldn’t see a change, but there were rare occurrences where steroids helped. To both Leah and her doctor’s surprise, after about a week of steroids, she completely regained hearing in her right ear. It was a “miracle.” Leah wonders whether she can count on a new miracle to heal her current medical issues.

1. What movements are involved in the action of standing up? What major muscles need to contract to perform these actions?

Example: Movements and muscles involved in scratching your nose: Elbow flexion - Biceps Brachii, Shoulder flexion, - Deltoid

2. Are Leah’s medical problems related to her sensory neurons, motor neurons, or both? What in Leah’s medical history supports your answer?

Answer 1

Ans 1) The muscles which are involved the action of standing up, the movement which is important is the extension of the hip joint as well as straightening of thigh in the backward motion. Standing up also requires extension of the knees and flexing the ankle planter which helps in the feet moving away from the shins. There are many contraction movements which helps in the standing up action and there are many muscles which are involved in the same. The gluteus maximus muscles are the one which helps in movement of the hips whereas the quadriceps muscles are in front of the thighs which helps in controlling the movement of the knees. The soleus muscles are in the calves and it helps in controlling the movement of ankles. As one stands up, there is concentric movement of the soleus muscle and they shorten upon contraction. Upon sitting down, the muscles tend to contract eccentrically and hence they lengthen.

Ans 2) The loss of hearing is mostly due to the sensory neurons and this might be because of lack of the neurons to transmit the signals. Due to the problem in the spinal cord, it is not able to transmit the sensory signals from ear to the central nervous system. This is supported by medical history of feeling numbness and tingling sensation and this is caused majorly due to compression in the spinal cord which leads to lack of neurons being able to transmit the signals.