QUESTI 15 points Save Answer Describe the sequence of events in the patellar ten

Question

QUESTI 15 points Save Answer Describe the sequence of events in the patellar tendon stretch reflex that cause the lower leg to reflexively extend when the tendon is sharply struck with a mallet. Include in your answer the role of muscle spindles, afferent neurons, interneurons, efferent neurons, and reciprocal inevation. T T Arial 3 (12pt) Path: p Words:0 QUESTI 10 points Save Answer Describe the accomodation reflex. Include in you answer the stimulus, response, afferent and efferent nerves, and the integration center in your answer.

Explanation / Answer

When we strike the pattelar tendon with a mallet just below the pattela it stretches the muscle spindles in the quadriceps muscles. A impulse is produced which travels via the afferent nerves to the spinal cord and synapses without interneuron at L3 in spinal cord. From there alpha motor neurons conduct impulse via efferent nerves back to quadriceps muscles to cause contraction. This contraction with the help of relaxation of the antagonistic flexion hamstring muscle causes the leg to kick. There is an inhibitory interneuron to relax the antagonistic hamstring muscle. This contraction (agonist) and relaxation (antagonist) control is reciprocal innervation.

Accommodation reflex is the reflex action of the eye in response to a stimulus to focus on a near object and then to look at the distant object and then doing the vice versa. This involves changes in vergence, changes in lens size and changes in pupil size i.e. accommodation. Impulses from afferent nerve pass along the normal visual pathway to the integration center such as visual areas in occipital lobe and third cranial nerve. From the visual area the nerve fibres enters the occulomotor( i.e third cranial nerve) nucleus of both sides in the mid brain. Impulses from Efferent fibres pass along the third cranial nerve to the eye to supply pupil muscle, ciliary muscle, Medial rectus muscle.

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