Tag: endocrine system in humans

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Multiple choice biology chemical coordination and integration mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Choose the correct answer from the alternatives givens.
In a negative feedback mechanism:

  1. the output cancels the input

  2. there is a fluctuation above and below the average

  3. there is self-regulation

  4. a regulatory center communicates with other body parts
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

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.

So, the correct answer is 'there is self-regulation'

Multiple choice biology chemical coordination and integration mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

How does chemical coordination take place in animals?

  1. Endocrine glands----> hormones-----> blood----> organs / tissues----> biochemical / physiological activity.

  2. Endocrine glands----> hormones----> biochemical / physiological activity-----> blood----> organs / tissues.

  3. Hormones----> biochemical / physiological activity-----> blood----> organs / tissues----> endocrine glands.

  4. Hormones----> biochemical / physiological activity-----> endocrine glands----> blood----> organs / tissues
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Endocrine glands----> hormones-----> blood----> organs / tissues----> biochemical / physiological activity.

Chemical coordination in multicellular organisms take place through the special chemical substances called hormones, which are produced in endocrine glands. These chemicals unlike nerve cells, reach all the cells of the body and bring about desirable changes as instructed by the brain and spinal cord. This is done by using a hormone named adrenaline. It is directly secreted into the blood and carried to different parts of the body. The heart, beats faster to supply more oxygen to our muscles. The breathing rate also increases. All these responses enable the animal body to be ready to face the situation. Such hormones constitute a second way of control and coordination.

Multiple choice biology chemical coordination and integration mechanism of hormone action coordination in human beings- chemical control endocrine system in humans
Feed back inhibition of an enzyme is influenced by

  1. Enzyme itself

  2. External factors

  3. End product

  4. Substrate
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

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'.

Multiple choice biology chemical coordination and integration mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

In feedback inhibition, a metabolic pathway is switched off by the accumulation of end products.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

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.

Hence, the correct answer is 'true'.

Multiple choice biology chemical coordination and integration mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Feed back mechanism controls

  1. Nervous system

  2. Enzyme production

  3. Time and amount of hormones released by endocrine glands

  4. Salivation
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

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.

So, the correct option is 'Time and amount of hormones released by endocrine glands'.

Multiple choice biology chemical coordination and integration mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Group of hormones which is released with cytoplasmic bounded receptors?

  1. Hypothalamic hormones and epinephrine

  2. Thyroid hormone and estradiol

  3. Insulin and glucagon

  4. GH and MSH
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

There are two sets of nerve cells in the hypothalamus that produce hormones.

One set sends the hormones they produce down through the pituitary stalk to the posterior lobe of the pituitary gland where these hormones are released directly into the bloodstream. These hormones are anti-diuretic hormone and oxytocin.
So, the correct option is 'Hypothalamic hormones and epinephrine.

Multiple choice biology chemical coordination and integration mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

A feedback mechanism regulates the action of the 

  1. Hormones

  2. Lipids

  3. Cell division

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

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. 

So, the correct answer is option A.

Multiple choice biology chemical coordination and integration mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Which of the following is an example of a negative feedback?

  1. Sucking reflex

  2. Uterine contractions during labour

  3. Secretion of CRH in response to ACTH

  4. Hair erection due to low body temperature
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

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.

So the correct option is ' secretion of CRH in response to ACTH'

Multiple choice biology chemical coordination and integration mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

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?

  1. The ovaries signal the rest of the body tissues by varying the level of estrogen.

  2. Conscious awareness of the arrival of a baby triggers the mother's hypothalamus to secrete prolactin.

  3. The hypothalamus and pituitary that triggered the female reproductive cycle also schedule milk production on a nine-month clock basis.

  4. 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.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

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.

Multiple choice biology chemical coordination and integration mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Which one is a positive feedback mechanism?

  1. Sexual stimulation

  2. Allosteric inhibition

  3. Blood pressure

  4. Perspiration
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

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 $(B)$