Answer:
every muscle cell of the motor unit is stimulated to contract.
Explanation:
Stimulus in biology can be defined as an obvious change in either the chemical or physical structure of an organism' environment (either external or internal). Thus, all living organisms (both animals and plants) respond to changes in their environment and consequently, an appropriate response or reaction is made. Also, stimulus arising from within the organism is known as internal stimulus while those from its environment are known as the external stimulus.
In organisms, the specialized cells that detect stimulus are generally known as sensory receptors while a group of these receptors is referred to as sense organ. Therefore, the senses are necessary for behavior because stimuli must be sensed in order to respond.
Stimulus control can be defined as a phenomenon that arises when a living organism responds or behaves in the presence of a stimulus and in another way in the absence of a stimulus.
For example, opening the door of a microwave oven as soon as its timer beeps.
Example II; When your body touches a hot object, you quickly move away and feel some pain subsequently.
Action potentials generates the nerve impulse in a motor neuron.
When an action potential is generated within a motor neuron, every muscle cell of the motor unit is stimulated to contract.
The answer to question one is a dissecting microscope.
The answer to question two is the third option about three-dimensional images
Answer:
For involuntary actions (reflexes) the information is first detected in the sensor and travels along sensory neurons to the spinal cord. Once the action potential reaches the spinal cord, the information is transmitted across the synapse to the motor neuron. for voluntary actions,
movements are commanded by the motor cortex, the zone of the cerebrum located behind the frontal lobe. The motor cortex sends a neural message that moves through the brain stem along the spinal cord and into the neural network to the muscle being commanded.
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