39. In experimental preparations, activation of the corticospinal tract can result in excitation of both a- and y-motoneurons. The co-activation of a- and y-motoneurons confers which of the following advantages compared with activation of only a-motoneurons? A) Decreased tension in the intrafusal muscle fibers increases the force of muscle contraction. B) Inhibition of y-motoneurons is overcome by activity in recurrent collaterals of a-motor axons C) y-Motoneuron axon collaterals excite a-motoneurons, increasing their total activity D) Muscle spindles shorten, preventing an unloading effect on muscle spindle sensory endings

Define what the NMJ is and why it's important for muscle contraction. Explain in short the process of the NMJ signaling the muscle to contract.  Note the difference between a motor unit and the NMJ.

Please help Why does TTX reduce the response caused by nerve stimulation and also the response to direct muscle stimulation?

Most immediate physiological adjustments to exercise occur prior to any change in tissue metabolic demand for oxygen or nutrients.  This occurs because exercise increases sympathetic nervous system activity.  With your knowledge of exercise and the control of alpha motor neurons by the primary motor cortex of the brain, how does increased exercise influence the sympathetic nervous system?

61.

Calcium entry through NNDA receptor can potentiate synaptic transmission through the following mechanisms EXCEPT:  a.) Insertion of AMPA receptors to postsynaptic membrane b.) Synthesis of NO to increase presynaptic transmitter release c.) Phosphorylation of AMPA  receptors d.) Slowing down glutamate reupdate, so it remains longer in the synapse

33) which of the following is released into the synaptic cleft and is responsible for depolarizing the sarcolemma? a) tropomyosin b) acetylcholine  c) troponin  d) cal

35. Which of the following sentences is CORRECT? A. Intercalated disc is absent in smooth muscle and skeletal muscle B. The contraction of smooth muscle cells is slow, but they can remain contracted for long periods C. Cerebellar cortex is composed of outer molecular layer, central layer of Purkinje cells, and granule layer D. Ganglia are ovoid structures containing neuronal cell bodies and glial cells supported by connective tissue

Provide a explantion and diagram of the  Intracellular mechanism of smooth muscle relaxation via antagonists such as atropine binding and blocking muscarinic receptors M3.   explain how  Atropine blocks the acetylcholine receptors

In an experiment, it was determined that the motor (effector) neuron for muscle fibre 1 had a threshold level of -5 mV. The motor (effector) neuron for muscle fibre 2 had a threshold level of -16 mV. An electrical probe was used to stimulate these two effector neurons of the muscle fibres. Which of the following rows correctly identifies the reaction of each muscle fibre based on the applied stimulus voltage? Select one: а. Stimulus Voltage Muscle Fibre 1 Muscle Fibre 2 -10 mV Contracted Relaxed b. Stimulus Voltage Muscle Fibre 1 Muscle Fibre 2 -20 mV Relaxed Contracted С. Stimulus Voltage Muscle Fibre 1 Muscle Fibre 2 - 10 mV Relaxed Contracted d. Stimulus Voltage Muscle Fibre 1 Muscle Fibre 2 - 20 mV Contracted Relaxed