A & P 1
A: Long-term, untreated leprosy may cause people lose the use of their hands or feet due to repeated injury because they lack feeling in those areas of the body. Ultimately, all forms will cause nerve damage in the arms/hands and legs/feet, causing sensory loss in the skin and muscle weakness. This may cause the person with leprosy to lose an extremity affected by the disease. B: Schwann cells are involved in many important aspects of peripheral nerve biology. The conduction of nervous impulses along axons, nerve development and regeneration, trophic support for neurons, production of the nerve extracellular matrix, modulation of neuromuscular synaptic activity, and presentation of antigens. The nerve impulses along the axons are most likely not functioning properly. C: The Achilles reflex is tested by asking the patient to relax his/her leg while the doctor supports the foot so that the ankle is held at a 90 degree angle. The doctor then strikes the Achilles tendon with a reflex hammer and determines and feels the dorsiflexion of the foot with his other hand. The Babinski sign is elicited by stroking the bottom of the foot in a "J" shape (starting near the outside of the heel and progressing toward the great toe). If the Babinski sign is present, then the great toe will extend while the other toes will flex. Dianna evaluated somatic, visceral, and special sensing when she preformed these tests on Sannu. D: The brain receives two types of sensations: (1) superficial sensations, including pain, temperature and crude touch, and (2) deep sensations, including sense of position, sense of movement, vibration sense, muscle sense and fine touch. Pathway of pain, temperature and crude touch sensations: (1) the first order neuron is present in the posterior root ganglion. Its dendrite passes to the periphery to act as a pain receptor, while its axon passes towards the spinal cord. (2) The second order neuron is...