Tag: endocrine system in humans
Questions Related to endocrine system in humans
Choose the correct answer from the alternatives givens.
In a negative feedback mechanism:
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the output cancels the input
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there is a fluctuation above and below the average
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there is self-regulation
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a regulatory center communicates with other body parts
Negative feedback, a self-regulated process occurs when some function of the output of a system process, or mechanism is fed back in a manner that tends to reduce the fluctuation in the output whether caused by the changes in the input or by other disturbance.
How does chemical coordination take place in animals?
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Endocrine glands----> hormones-----> blood----> organs / tissues----> biochemical / physiological activity.
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Endocrine glands----> hormones----> biochemical / physiological activity-----> blood----> organs / tissues.
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Hormones----> biochemical / physiological activity-----> blood----> organs / tissues----> endocrine glands.
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Hormones----> biochemical / physiological activity-----> endocrine glands----> blood----> organs / tissues
Endocrine glands----> hormones-----> blood----> organs / tissues----> biochemical / physiological activity.
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Enzyme itself
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External factors
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End product
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Substrate
In feed back inhibition product of a reaction inhibits the enzyme catalysing that reaction. It is a type of control mechanism at the enzyme level. If the product is produced in sufficient amount, it inhibits the enzyme to stop the further production. So, the correct answer is 'End product'.
In feedback inhibition, a metabolic pathway is switched off by the accumulation of end products.
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True
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False
Accumulation of end products triggers an inhibiting action as a feedback inhibition of the metabolic pathway causing its inhibition. as a result, the metabolic pathway is switched off or halted. For example, the absence of the suckling stimulus leads to inhibition of the milk secretion.
Feed back mechanism controls
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Nervous system
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Enzyme production
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Time and amount of hormones released by endocrine glands
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Salivation
Most hormones are regulated by feedback mechanisms. A feedback mechanism is a loop in which a product feeds back to control its own productions. Most negative feedback loops get involved from hormone feedback mechanisms. Here the time delay occurs and hormones are released.
Group of hormones which is released with cytoplasmic bounded receptors?
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Hypothalamic hormones and epinephrine
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Thyroid hormone and estradiol
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Insulin and glucagon
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GH and MSH
There are two sets of nerve cells in the hypothalamus that produce hormones.
A feedback mechanism regulates the action of the
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Hormones
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Lipids
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Cell division
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None of the above
The feedback mechanism is the process wherein the upregulation and downregulation of genes, hormones, homoeostasis and other factors are controlled. For example, if the level of sugar concentration in blood has increased feedback mechanism upregulates the hormone insulin which helps to stabilise the sugar in the blood.
Which of the following is an example of a negative feedback?
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Sucking reflex
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Uterine contractions during labour
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Secretion of CRH in response to ACTH
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Hair erection due to low body temperature
One distinctive feature of hormones whose secretion is regulated through the hypothalamus and pituitary is that they regulate their own secretion through negative feedback inhibition. CRH (corticotropin releasing hormone) and ACTH (adrenocorticotropic hormone). Less tropic hormone secretion leads to less stimulation of cortisol secretion by cells of the zona fasciculata of the adrenal cortex. The usefulness of negative feedback inhibition is that it works to keep hormone levels within a particular appropriate physiological range. The reduced negative feedback inhibition means that more CRH and ACTH will be secreted. More ACTH will stimulate the remaining adrenal tissue to grow and to secrete more cortisol. This will have the effect of bringing cortisol back up towards its normal daily level of secretion.
Consider the synchronization of birth and milk production. Babies can be born several months prematurely, and milk production is needed immediately after birth. How has the human body evolved to coordinate this delicate timing of events?
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The ovaries signal the rest of the body tissues by varying the level of estrogen.
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Conscious awareness of the arrival of a baby triggers the mother's hypothalamus to secrete prolactin.
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The hypothalamus and pituitary that triggered the female reproductive cycle also schedule milk production on a nine-month clock basis.
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Oxytocin both causes the uterus to contract in labor and stimulates the release of milk from mammary glands, which is reinforced by prolactin from the pituitary.
The hypothalamus and pituitary that triggered the female reproductive cycle do not schedule milk production on a nine-month clock basis. But oxytocin is released due to the stimulation by fetal ejection reflex. By this stimulation, oxytocin is released which causes contraction in uterus wall and also stimulates prolactin secretion for milk production in mammary gland. Thus, the correct answer is option D.
Which one is a positive feedback mechanism?
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Sexual stimulation
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Allosteric inhibition
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Blood pressure
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Perspiration
Allosteric inhibition is the regulation of an enzyme by an effector molecule that binds to a site other than the active site, which is called allosteric site. Since it is not blocking the active site it is called 'positive feedback' option $(B)$