Physiology And Anatomy Essay Sample

Physiology And Anatomy Essay Sample

Part one:

  1. If you step up one step using your right leg, the impulse will arise from the motor cortex in the left cerebral hemisphere of your brain.
  2. The impulse then travels through the corticobulbar tract through the midbrain, then the pons and medulla until it exits the skull through the occipital foramen and enters your spinal cord.
  3. In the spinal cord, the impulse travels down until the tract decussates to the right side of the cord and synapse with the right lateral corticospinal tract.
  4. From the spinal cord the impulse travels through specific nerves that branch outside the spinal column to specific muscle groups depending on the movement.
  5. The action of stepping up one step involves two motions: first, the flexion of your hip joint and knee joint as you place your feet one step up; second, the extension of both joints as you pull your self up.
  6. For the first motion, the impulse will travel through the femoral nerve which innervates your sartorius, ileus, and psoas muscles which pulls the femur and flex the hip joint.  At the same time, the impulse will also travel through the obturator nerve that supply the gracilis, and through the sciatic nerve that supplies the biceps femoris , semitendinosus, and semimembranosus muscles causing them to contract and flexing the tibia and fibula of the lower leg  at the knee joint.
  7. For the second motion, your hips are extended by the action of the gracilis, adductor longus, brevis and magnus muscles through the impulse that travels through obturator nerve that innervates them.  At the same time, your leg is extended at your knee joint by way of the impulse from the femoral nerve that innervates the quadratus femoris muscle.

Part two:

  1. When you reach your right arm to reach something above your head, the impulse will also arise from the motor cortex in the left cerebral hemisphere of your brain.
  2. The impulse then travels through the corticobulbar tract through the midbrain, then the pons and medulla until it exits the skull through the occipital foramen and enters your spinal cord.
  3. In the spinal cord, the impulse travels down until the tract decussates to the right side of the cord and synapse with the right lateral corticospinal tract.
  4. From the spinal cord the impulse travels through specific nerves that branch outside the spinal column to specific muscle groups depending on the movement.
  5. Since your shoulder joint is capable of several movements, lets just say you want to raise you hand forward.  Three simultaneous motions also occur. Flexion, adduction, and medial rotation on your shoulder joint.
  6. For the first motion, the impulse will contract the axillary your deltoid (through the axillary nerve), pectoralis major(pectoral nerves), biceps(musculocutaneous nerve), and coracobrachialis(musculocutaneous nerve)which flexes the humerus at the shoulder joint. knee joint.
  7. At the same time, the pectoralis major(pectoral nerves), latissimus dorsi and teres major(subscapular nerve) and teres minor(axillary nerve)  muscles will adduct the humerus.
  8. Finally, the subscapularis(subscapular nerve), latissimus dorsi(thoracodorsal nerve), teres major(subscapular nerve) and anterior fibers of the deltoid(axillary nerve) will medially rotate the humerus at the shoulder joint