Tag: chemical coordination and integration

Questions Related to chemical coordination and integration

How does chemical coordination take place in animals?

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

  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

Show answer
Correct Option: A
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.

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

  1. Enzyme itself

  2. External factors

  3. End product

  4. Substrate

Show answer
Correct Option: C
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'.

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

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

  1. True

  2. False

Show answer
Correct Option: A
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'.

Feed back mechanism controls

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

  1. Nervous system

  2. Enzyme production

  3. Time and amount of hormones released by endocrine glands

  4. Salivation

Show answer
Correct Option: C
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'.

Group of hormones which is released with cytoplasmic bounded receptors?

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

  1. Hypothalamic hormones and epinephrine

  2. Thyroid hormone and estradiol

  3. Insulin and glucagon

  4. GH and MSH

Show answer
Correct Option: A
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.

A feedback mechanism regulates the action of the 

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

  1. Hormones

  2. Lipids

  3. Cell division

  4. None of the above

Show answer
Correct Option: A
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.

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

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

  1. Sucking reflex

  2. Uterine contractions during labour

  3. Secretion of CRH in response to ACTH

  4. Hair erection due to low body temperature

Show answer
Correct Option: C
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'

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?

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

  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.

Show answer
Correct Option: D
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.

Which one is a positive feedback mechanism?

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

  1. Sexual stimulation

  2. Allosteric inhibition

  3. Blood pressure

  4. Perspiration

Show answer
Correct Option: B
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 $(B)$

Positive feedback loop between cytokines and immune cells can cause

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

  1. Hypocytokinemia

  2. Hypercytokinemia

  3. Immune deficiency

  4. None of the above

Show answer
Correct Option: B