Physiology Study Guide 13: Somatic Motor Reflexes 3

Steven A. Fink; Instructor

PHYSIOLOGY STUDY GUIDE 13:

SOMATIC MOTOR REFLEXES

True/False

____ 1. Somatic motorneurons possess receptor sites for only 1 type of neurotransmitter.

____ 2. Passive stretching of a skeletal muscle causes a reflex contraction of that muscle back to its orginal length.

____ 3. Stepping on a pin causes the flexor muscle of the affected leg to contract.

____ 4. Subconscious adjustments to posture & balance are controlled by the Cerebral cortex.

____ 5. Reflexes are only innate and can not be learned.

____ 6. After stepping on a pin with one leg, there is a reflex extension of the contralateral leg.

____ 7. Tapping a tendon with a reflex hammer stretches a muscle, causing a reflex contraction of that same muscle.

____ 8. Muscles are maintained at fixed lengths by withdrawal reflexes.

____ 9. The muscle tone present in resting muscles is consciously maintained by the cerebral cortex.

____10. Muscle spindles contain hair cell sensory neurons.

____11. After stepping on a pin with one leg, there is a reflex extension of the ipsilateral leg.

____12. Stepping on a pin causes the extensor muscle of the affected leg to relax.

Multiple Choice

____13. Skeletal muscle tension (tonus) at rest is maintained subconsciously by the:
(a) Hypothalamus
(b) Midbrain
(c) Limbic System
(d) Cerebellum
(e) Basal (Ganglia) Nuclei

____14. Stretch reflexes like the "knee jerk" primarily act to:
(a) withdraw limbs from harm
(b) counteract gravity
(c) initiate voluntary movement
(d) maintain internal homeostasis
(e) prevent sensory overload

____15. The contraction of one muscle, and the simultaneous relaxation of its antagonist is called:

(a) dual innervation

(b) reciprocal innervation

(d) spatial summation

(e) automaticity

___16. Muscle spindles are innervated by both:

(a) somatic sensory neurons & alpha-somatic motorneurons

(b) somatic sensory neurons & gamma-somatic motorneurons

(d) visceral sensory neurons & alpha-somatic motorneurons

(e) visceral sensory neurons & gamma-somatic motorneurons

____17. The conscious control of skeletal muscles originates in the:
(a) Frontal Lobe of the Cerebral Cortex
(b) Parietal Lobe of the Cerebral Cortex
(c) Temporal Lobe of the Cerebral Cortex
(d) Occipital Lobe of the Cerebral Cortex
(e) Cerebellum

____18. Which one of the following muscles causes extension of the leg?
(a) Biceps femoris
(b) Quadriceps femoris
(c) Triceps brachii
(d) Biceps brachii
(e) Gastrocnemius

____19. Which one of the following is often referred to as an "upper motorneuron”?
(a) sympathetic preganglionic motorneuron
(b) somatic motorneuron
(c) somatic sensory neuron
(d) parasympathetic postganglionic motorneuron
(e) pyramidal tract interneuron

____20. The Primary Motor Area of the Cerebral cortex is located in the:
(a) precentral gyrus of the Frontal Lobe
(b) postcentral gyrus of the Parietal Lobe
(c) Temproal Lobe
(d) Occipital Lobe
(e) Limbic System

____21. Injury to a “Lower Motorneuron” results in:
(a) kinesthesia
(b) spastic paralysis
(c) flaccid paralysis
(d) coma
(e) tingling sensation

____22. Voluntary control of the muscles that move your hand originate in the:
(a) top portion of the precentral gyrus
(b) bottom portion of the precentral gyrus
(c) top portion of the postcentral gyrus
(d) bottom portion of the postcentral gyrus
(e) Hypothalamus
(ab) Cerebellum