Answer:
A dorsal root (sensory or afferent) and a ventral root (motor or efferent) originate from the medulla. They unite near the intervertebral foramen, forming the spinal nerve. The nerves emerge from the intervertebral foramen, dividing into ventral and dorsal ramus.
Explanation:
The nerve is a set of nerve fibers perceptible to the naked eye and wrapped in connective tissue. They are made up of roots, trunks and nerve branches (some of them come together and form plexuses).The spinal nerve originate from the spinal cord in the form of 31 pairs: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 1 coccygeal. They emerge from the spinal cord through two roots: dorsal roots, made up of sensory fibers that come from the sensory neurons of the spinal ganglion and that penetrate the spinal cord through the posterolateral and ventral root, made up of motor fibers, coming from the motor neurons of the anterior horn and visceral of the lateral horn of the gray matter of the spinal cord. This root exits the spinal cord through the anterolateral groove, then joins the posterior root to form the spinal nerve, which exits the vertebral canal through the corresponding intervertebral foramen.Each spinal nerve, after leaving the vertebral canal, emits two primary ramus: the dorsal ramus, contains somatic and visceral fibers that go to the skin and muscles of the back and the ventral ramus, which supplies the ventrolateral surface of the skin, body wall and extremities.
According to Selye's theory of stress, during the condition of the stress, the body undergoes the general adaptation syndrome, which occurs in three stages. These three stages are fight or flight, resistance reaction, and exhaustion.
The flight or fight reaction is stimulated by the hypothalamus. It results in the excitement of the sympathetic division of the autonomic nervous system. The resistance reaction is caused by the hormones released by the hypothalamus; this is long lasting and provides ATP (adenosine triphosphate) molecules for the counter reaction to the stress.
As the result of use of ATP and other energy resource from body during the resistance reaction, the body becomes deprived of energy. This causes the exhaustion in the body.
So, the resistance phase of the stress expands a considerable amount of energy, which causes exhaustion.
Answer:
D.autonomic nervous system
Answer:
the surroundings or conditions in which a person, animal, or plant lives or operates
