Question

1. linjection massive de testostérone dans lorganisme provoquerait :

a. une augmentation des concentrations plasmatiques de fsh et de lh
b. une diminution des concentrations plasmatiques de fsh et de lh
c. une augmentation de la sécrétion de gnrh
d. une diminution de la sécrétion de gnrh

1. la régulation du taux de testostérone chez ladulte :

a. est le résultat dun équilibre dynamique entre les activités des testicules et celles du complexe hypothalamo-hypophysaire
b. fait intervenir un rétrocontrôle négatif de lhormone testiculaire qui stimule lhypothalamus
c. a pour but dimposer une variation cyclique de la sécrétion de testostérone dans le sang
d. a pour but de maintenir à une certaine valeur de référence le taux de testostérone

1. linhibine :

a. est un stéroïde hormonal
b. est sécrétée par les cellules de sertoli
c. intervient dans la régulation du taux de lh
d. stimule la sécrétion de labp

1. la sécrétion de gnrh chez ladulte:

a. est contrôlée
b. est pulsatile
c. est continue
d. se fait dans la circulation générale

1. la gnrh :

a. provoque la sécrétion de la testostérone et de linhibine par les testicules
b. provoque la sécrétion des gonadostimulines hypophysaires
c. est une protéine
d. a un rythme de sécrétion stable chez ladulte

1. lablation de lhypothalamus à un animal pubère, provoquerait :

a. une augmentation de la sécrétion de lh et de fsh
b. un arrêt de la sécrétion de fsh et de lh
c. un arrêt de lactivité testiculaire
d. la régression des caractères sexuels secondaires

1. lh et fsh sont :

a. des gonadolibérines
b. des gonadostimulines
c. de nature protéique
d. libérées dans la tige pituitaire

1. la sécrétion de fsh et de lh chez ladulte est :

a. régulée
b. continue et croissante
c. permise par la sécrétion pulsatile de gnrh
d. permise par la sécrétion de la testostérone

1. la régulation hormonale de la fonction reproductrice chez lhomme :

a. est un mécanisme autorégulé
b. fait intervenir des hormones qui sont : la gnrh ; la lh ; la fsh ; la testostérone et linhibine
c. débute à la naissance
d. fait intervenir des rétrocontrôles positifs et négatifs

1. une hypophysectomie chez lhomme provoquerait :

a. une chute des sécrétions des hormones testiculaires
b. une augmentation de la concentration plasmique de testostérone
c. une chute de la sécrétion de gnrh
d. une augmentation de la sécrétion de gnrh

1. lablation des testicules chez lhomme provoquerait :

a. une chute des sécrétions hormonales hypophysaires

Answer:

To solve these multiple - choice questions related to the male reproductive endocrine system, we analyze each question one by one:

Question 10

• Analysis of options:
• When there is a massive injection of testosterone, according to the negative feedback mechanism, the high level of testosterone will inhibit the secretion of GnRH (Gonadotropin - Releasing Hormone) from the hypothalamus and FSH (Follicle - Stimulating Hormone) and LH (Luteinizing Hormone) from the pituitary gland.
• Option a: High testosterone levels will inhibit FSH and LH secretion, not increase them. So option a is wrong.
• Option b: High testosterone levels will inhibit FSH and LH secretion, not increase them. So option b is wrong.
• Option c: High testosterone levels will inhibit GnRH secretion, not increase it. So option c is wrong.
• Option d: High testosterone levels will inhibit GnRH secretion. So option d is correct.
• Answer: d

Question 11

• Analysis of options:
• The regulation of testosterone levels in adults is a dynamic balance between the testes and the hypothalamic - pituitary complex. It also involves negative feedback (not positive) and the goal is to maintain testosterone levels at a certain reference value.
• Option a: The regulation of testosterone is a dynamic balance between the testes and the hypothalamic - pituitary complex. This option is correct.
• Option b: It is negative feedback, not positive feedback, that regulates the hormone that stimulates the hypothalamus. So option b is wrong.
• Option c: The purpose is to maintain testosterone levels, not to restore a cyclic variation of testosterone levels. So option c is wrong.
• Option d: The purpose is to maintain testosterone levels at a certain value, not just a “certain value of reference” in a vague sense. The main idea is the dynamic balance. So option d is wrong.
• Answer: a

Question 12

• Analysis of options:
• Inhibin is a hormone (a glycoprotein) secreted by Sertoli cells. It has a negative feedback effect on FSH secretion.
• Option a: Inhibin is a hormonal substance (a glycoprotein hormone). So option a is correct.
• Option b: Inhibin is secreted by Sertoli cells, not Leydig cells. So option b is wrong.
• Option c: Inhibin regulates FSH, not LH. So option c is wrong.
• Option d: Inhibin does not stimulate ABP (Androgen - Binding Protein) secretion. So option d is wrong.
• Answer: a

Question 13

• Analysis of options:
• GnRH secretion in adults is pulsatile. This pulsatile secretion is important for the normal secretion of FSH and LH.
• Option a: GnRH secretion is not “controlled” in a simple sense here. The key is its pulsatile nature. So option a is wrong.
• Option b: GnRH secretion is pulsatile. So option b is correct.
• Option c: GnRH secretion is not continuous. So option c is wrong.
• Option d: GnRH is secreted by the hypothalamus, not in the general circulation. So option d is wrong.
• Answer: b

Question 14

• Analysis of options:
• GnRH (Gonadotropin - Releasing Hormone) promotes the secretion of gonadotropins (FSH and LH) from the pituitary gland.
• Option a: GnRH acts on the pituitary gland, not directly on the testes to promote or inhibit testosterone secretion. So option a is wrong.
• Option b: GnRH promotes the secretion of pituitary gonadotropins (FSH and LH). So option b is correct.
• Option c: GnRH is a peptide, not a protein. So option c is wrong.
• Option d: GnRH secretion is pulsatile, not with a stable rhythm. So option d is wrong.
• Answer: b

Question 15

• Analysis of options:
• If the hypothalamus is ablated, the secretion of GnRH will stop. Since GnRH stimulates the pituitary to secrete FSH and LH, the secretion of FSH and LH will also stop.
• Option a: Without hypothalamic stimulation, FSH and LH secretion will decrease, not increase. So option a is wrong.
• Option b: The secretion of FSH and LH will stop, not just decrease. So option b is wrong.
• Option c: The secretion of FSH and LH will stop, which will lead to the arrest of testicular activity (since FSH and LH are necessary for testicular function). So option c is correct.
• Option d: Without the stimulation of sex hormones (which depend on FSH and LH), the secondary sexual characteristics will regress, but this is a consequence of the arrest of testicular activity. The most direct effect of hypothalamic ablation is the arrest of FSH and LH secretion, leading to testicular activity arrest. So option d is not the most direct answer.
• Answer: c

Question 16

• Analysis of options:
• LH (Luteinizing Hormone) and FSH (Follicle - Stimulating Hormone) are gonadotropins (gonadostimulins) and they are proteins (glycoproteins) and they are released from the anterior pituitary (tige pituitaire).
• Option a: Gonadolibérines are GnRH, not LH and FSH. So option a is wrong.
• Option b: LH and FSH are gonadostimulins (they stimulate the gonads). So option b is correct.
• Option c: LH and FSH are of protein nature (glycoproteins). So option c is correct.
• Option d: LH and FSH are released from the anterior pituitary (tige pituitaire). So option d is correct.
• Answer: b, c, d

Question 17

• Analysis of options:
• The secretion of FSH and LH in adults is regulated. It is permitted by the pulsatile secretion of GnRH. And it is also regulated by the negative feedback of testosterone.
• Option a: The secretion of FSH and LH is regulated. So option a is correct.
• Option b: The secretion is not continuous and increasing. It is pulsatile and regulated. So option b is wrong.
• Option c: The pulsatile secretion of GnRH is necessary for the normal secretion of FSH and LH. So option c is correct.
• Option d: The secretion is permitted by the pulsatile secretion of GnRH, and also regulated by testosterone feedback. So option d is correct.
• Answer: a, c, d

Question 18

• Analysis of options:
• The hormonal regulation of male reproductive function involves multiple hormones (GnRH, LH, FSH, testosterone, inhibin) and both positive and negative feedbacks (negative feedback is more prominent, but there are also some positive feedback elements in the system). It starts at puberty. And it is not an automatic mechanism, but a neuro - endocrine mechanism.
• Option a: It is not an automatic mechanism, but a neuro - endocrine regulation. So option a is wrong.
• Option b: The hormones involved in the regulation of male reproductive function are GnRH, LH, FSH, testosterone, and inhibin. So option b is correct.
• Option c: The hormonal regulation of male reproductive function starts at puberty. So option c is correct.
• Option d: The regulation involves both positive and negative feedbacks (negative feedback is mainly for testosterone on the hypothalamus and pituitary, and there are some positive feedback loops in the system). So option d is correct.
• Answer: b, c, d

Question 19

• Analysis of options:
• Hypophysectomy (removal of the pituitary) will lead to the loss of FSH and LH secretion. Since FSH and LH stimulate the testes to secrete hormones (testosterone, etc.), the secretion of testicular hormones will drop.
• Option a: Hypophysectomy will lead to a drop in testicular hormone secretion (because FSH and LH are no longer secreted to stimulate the testes). So option a is correct.
• Option b: Without pituitary stimulation, testosterone concentration will drop, not increase. So option b is wrong.
• Option c: Hypophysectomy will not directly affect GnRH secretion in the short term (GnRH is from the hypothalamus). So option c is wrong.
• Option d: Hypophysectomy will not lead to an increase in GnRH secretion. So option d is wrong.
• Answer: a

Question 20

• Analysis of options:
• If the testes are ablated, the negative feedback of testosterone (and inhibin) on the hypothalamus and pituitary will be removed. So the secretion of hypothalamic (GnRH) and pituitary (FSH, LH) hormones will increase.
• Option a: The secretion of hypophyseal (pituitary) hormones (FSH, LH) will increase, not drop. So option a is wrong.
• (Note: The original option description may be incomplete, but based on the knowledge of the negative feedback loop, after testicular ablation, the secretion of FSH and LH (hypophyseal hormones) will increase because the negative feedback from testosterone and inhibin is gone.)