answer:Epidemiology is the study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems (1). Key terms in this definition reflect some of the important principles of epidemiology.
Answer: The correct answer is-
C. Insulin secretion in response to high blood sugar.
D. Increased heart rate in response to exercise.
F. Proton pumping to maintain a proper pH level.
Homeostasis can be described as a tendency of living organisms to maintain a state of stable internal environment. In other words, it is the tendency to resist any change in the optimal conditions for survival.
It is brought by several regulatory mechanisms in the body such as regulation of body temperature, regulation of pH, regulation of osmolarity etc.
- Whenever there is high blood sugar level, insulin hormone is secreted from pancreas that reduces the blood sugar level.
- Heart rate is increased in response to exercise so that more oxygen is transported through blood circulation and more amount of energy is harvested through cellular respiration in the form of ATP ( required in exercise).
- Pumping of proton maintains a proper pH level ( such as in lysosomes, where pH is highly acidic, high proton concentration is regulated through proton pumping).
Thus, option C), D), and F) are the examples of feedback mechanisms that help in maintaining homeostasis.
Somatic motor neuron stimulation doesnot cause the release of a hormone from an endocrine organ.
Somatic motor neurons innervate skeletal muscles not endocrine organs. They originate in the central nervous system (CNS) and project their axons to the muscles involved in locomotion (limbs, abdominal). These neurons are called efferent because they transport information from the CNS to the periphery.
Hormone release from an endocrine organ can be caused by:
• Levels of circulating ions-e.g. Ca ions control the release of parathyroid hormones from parathyroid glands
• Another hormone- e.g Thyrotropin-releasing hormone (TRH) from hypothalamus affect the release of Thyroid-stimulating hormone (TSH) from the pituitary gland which then affect the release of thyroid hormones T4, T3 from thyroid gland
• Neural reflex arc-e.g. Parasympathetic neurons increase insulin secretion.
