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Both the nervous and the endocrine systems are involved when a person is in a dangerous situation - NSC Life Sciences - Question 4 - 2019 - Paper 1
Question 4
Both the nervous and the endocrine systems are involved when a person is in a dangerous situation. Describe the path of an impulse in a reflex arc during a reflex a... show full transcript
Worked Solution & Example Answer:Both the nervous and the endocrine systems are involved when a person is in a dangerous situation - NSC Life Sciences - Question 4 - 2019 - Paper 1
Step 1
Describe the path of an impulse in a reflex arc during a reflex action.
Answer
The reflex arc begins when the receptor receives a stimulus and converts it into an impulse. This impulse is then transmitted by a sensory neuron through the dorsal root of the spinal nerve.
Next, the impulse travels to the spinal cord where it is transferred via an interneuron to the motor neuron. The motor neuron carries the impulse via the ventral root to the effector, which can be a muscle or gland.
Finally, the impulse is transferred from one neuron to the next via a synapse, leading to the reflex action.
Step 2
Describe the role of different glands of the endocrine system in providing the body with extra energy during the dangerous situation.
Answer
During a dangerous situation, the adrenal glands secrete more adrenaline, which increases blood glucose levels, heart rate, breathing rate, and dilates blood vessels to essential organs.
Additionally, the pancreas (in particular the islets of Langerhans) releases more glucagon, which also increases blood glucose levels.
The pituitary gland increases the secretion of Thyroid Stimulating Hormone (TSH), which in turn stimulates the thyroid gland to produce more thyroxine.
Thyroxine works to increase the body’s metabolic rate and rate of respiration, providing the body with the necessary energy to respond effectively.