Question

The endocrine system incorporates feedback mechanisms that maintain homeostasis. Which of the following demonstrates negative feedback by the endocrine system?a. During labor, the fetus exerts pressure on the uterine wall, including the production of oxytocin, which stimulates uterine contraction. The contractions cause the fetus to push on the uterine wall , increasing production of oxytocin.b. After a meal, blood glucose levels become elevated, stimulating beta cells of the pancreas to release insulin into the blood. Excess glucose is then converted into glycogen in the liver, reducing blood glucose levels.c. At high elevations, atmospheric oxygen is more scarce. In response to signals that oxygen is low, the brain decreases an individual’s rate of respiration.d. A transcription factor binds to the regulatory region of a gene, blocking the binding of another transcription factor required for expression.

Answer 1

Answer is option B.

After a meal, blood glucose levels become elevated, stimulating beta cells of the pancreas to release insulin into the blood. Excess glucose is then converted into glycogen in the liver, reducing blood glucose levels.

Step-by-step explanation:

Homeostasis is the inclination of the various systems in the human body to stay in a normal, stable range for health by self-regulation through negative and positive feedback controls. It maintains equilibrium and provides stability to the human body.

A negative feedback loop (inhibitory loop) is a type of self-regulating system in which increased output from the system inhibits future production by the system. Examples of negative feedback to achieve homeostasis are blood pressure, body temperature, blood sugar, etc. During blood sugar homeostasis, when blood glucose levels rise, pancreatic beta cells release insulin. Insulin also converts glucose into glycogen (glycogenesis) for storage in the liver. When blood glucose levels decrease, pancreatic alpha cells release the hormone glucagon. In the liver, glucagon breaks down the stored glycogen into glucose (glycogenolysis). The glucose then enters the bloodstream and restores the blood glucose levels to normal.

In a positive feedback system, the original stimulus is amplified by the output. Examples of a positive feedback system are childbirth, lactation, blood clotting, etc. During childbirth, the hormone oxytocin released increases and speeds up the contractions.