Question

Part I

You are a volunteer in a California medical office of Dr. Williams. Dr. Williams specializes in rare neuromuscular and musculoskeletal disorders. You’re also a grad student and working with Dr. Williams has allowed you to gain first-hand experience with some of the material that you’re learning in your human physiology course.

Today a group of high school students is coming for a tour and Dr. Williams has asked you to prepare some information about muscles to present to the students, such as the neuromuscular junction (NMJ), skeletal muscle contraction, and issues that can arise when signaling between neurons and muscles does not happen as it is supposed to.

Questions [Critical Thinking and Communication]

1. Write a summary paragraph to explain the action of muscles to high school students as Dr. Williams instructed.

Answer 1

The muscular system contains more than 600 muscles that work together to enable the full function of the body.The main functions of muscular system are mobility,stability,posture,circulation,respiration,digestion,urination ,child birth,vision,organ protection, and temperature regulation   NEUROMUSCULAR JUNCTION is a chemical synapse between a motor neuron and a muscle fiber.It allows the motor neuron to transmit a signal to the muscle fiber ,causing muscle contraction .At the neuromuscular junction ,the nerve fiber is able to transmit a signal to the muscle fiber by releasing ACh[and other substance] causing muscle contraction.To exchange signals at neuro muscular junction [1]action potential reaches the axon terminal [2] volatage -dependent calcium gates open,allowing calcium to enter the axon terminal   [3] neurotransmoitter vesicles fuse with the presynaptic membrane and ACh is released into synaptic cleft via exocytosis [4]ACh binds to postsynaptic receptors on the sarcolemma [5] this binding causes iro channels to open and allows sodium and other cations to flow across the membrane into the muscle cell[6] the flow of sodium ions across the membrane into and potassium ions out of the muscle cell generates an action potential which travels to the myofibril and results in muscle contraction. muscles allow a person to move ,speak and chew.They control heart beat,breathing and digestion .In mobility ,muscle perform coordinated motions to walk,run and swim ,write and speak .For Stability   muscle tendons streatch over joints and contribute to joint stability .For Posture, skeletal muscleshelp keep the body in the correct position when sitting or standing. In circluation smmoth muscles in the ateries and veins plays a role In respiration muscles of diaphram controlls breath in and out .In digestion gastro intestinal tract stretches from mouth to anal area  and smooth muscles controls peristalsis.The muscles and nerves wust work together to hold and release urine from the bladder.Smooth muscles in the uterus expand and contract during child birth .Muscles in the torso protect the internal organs  and controlls heat through the skin