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, we analyze each one based on knowledge of endocrinology, specifically the hypothalamic - pituitary - testicular axis:

Question 10

• Explanation: 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), which in turn will lead to a decrease in the secretion of FSH (Follicle - Stimulating Hormone) and LH (Luteinizing Hormone).
• Option a: Incorrect, because testosterone inhibits FSH and LH secretion.
• Option b: Incorrect, the secretion of FSH and LH will decrease.
• Option c: Incorrect, the secretion of GnRH will decrease.
• Option d: Correct, as explained above.
• Answer: d. une diminution de la sécrétion de GnRH

Question 11

• Explanation: The regulation of testosterone levels in adults is a dynamic balance between the testes and the hypothalamic - hypophyseal complex. It also involves negative feedback (testosterone inhibits the hypothalamus and pituitary) and the goal is to maintain testosterone at a certain reference level.
• Option a: Correct, it is a dynamic balance between testicular and hypothalamic - hypophyseal activities.
• Option b: It is negative feedback, not positive, so incorrect.
• Option c: The regulation is not to reproduce a cyclic variation of secretion, so incorrect.
• Option d: Correct, the goal is to maintain the testosterone level at a certain reference value. But option a is more comprehensive in describing the regulation mechanism. However, if we consider the main regulatory relationship, the dynamic balance between the testes and the hypothalamic - hypophyseal complex (option a) is the basis for maintaining the testosterone level (option d). But in the context of the question, option d is more about the purpose of regulation. However, if we re - examine the options, the regulation of testosterone levels is a dynamic balance between the testes and the hypothalamic - hypophyseal complex (option a) and also aims to maintain the level (option d). But usually, the dynamic balance (option a) is the core mechanism. But there may be a mis - option setting. Wait, let's re - think. The regulation of testosterone in adults: the testes secrete testosterone, which feeds back to the hypothalamus and pituitary (negative feedback) to adjust the secretion of GnRH, LH, and FSH, so as to maintain the testosterone level. So the regulation is a dynamic balance between the testes and the hypothalamic - hypophyseal complex (option a), and the purpose is to maintain the testosterone level (option d). But if we have to choose one, option d is about the purpose, which is also correct. But maybe the intended answer is d.
• Answer: d. a pour but de maintenir à une certaine valeur le taux de testostérone dans le sang

Question 12

• Explanation: Inhibin is a hormone (glycoprotein) secreted by Sertoli cells. It has a negative feedback effect on the secretion of FSH, not LH.
• Option a: Inhibin is a hormonal substance (a glycoprotein hormone), so this is correct in terms of being a hormonal substance, but let's check other options.
• Option b: Inhibin is secreted by Sertoli cells, correct.
• Option c: Inhibin regulates FSH, not LH, so incorrect.
• Option d: Inhibin does not stimulate ABP (Androgen - Binding Protein) secretion, ABP is also secreted by Sertoli cells but is regulated by FSH. So the most accurate option is b.
• Answer: b. est sécrétée par les cellules de Sertoli

Question 13

• Explanation: The secretion of GnRH in adults is pulsatile. This pulsatile secretion is important for the normal secretion of LH and FSH.
• Option a: GnRH secretion is not controlled in the way described, incorrect.
• Option b: Correct, GnRH secretion is pulsatile.
• Option c: GnRH secretion is not continuous, incorrect.
• Option d: GnRH is secreted in the hypothalamus, not in the general circulation, incorrect.
• Answer: b. est pulsatile

Question 14

• Explanation: GnRH (Gonadotropin - Releasing Hormone) promotes the secretion of gonadotropic hormones (LH and FSH) from the pituitary gland.
• Option a: GnRH acts on the pituitary, not directly on the testes to promote testosterone secretion, incorrect.
• Option b: Correct, GnRH promotes the secretion of pituitary gonadotropins (LH and FSH).
• Option c: GnRH is a peptide, not a protein, incorrect.
• Option d: GnRH secretion is pulsatile, not stable, incorrect.
• Answer: b. provoque la sécrétion des gonadostimulines hypophysaires

Question 15

• Explanation: If the hypothalamus is ablated, the secretion of GnRH will stop. Since GnRH stimulates the pituitary to secrete LH and FSH, the ablation of the hypothalamus will lead to the stop of LH and FSH secretion.
• Option a: Incorrect, without GnRH, LH and FSH secretion will decrease, not increase.
• Option b: Correct, the ablation of the hypothalamus will stop the secretion of LH and FSH.
• Option c: The testicular activity will be affected (decrease) due to the lack of LH and FSH, not stop immediately, incorrect.
• Option d: The secondary sexual characteristics will regress, but the most direct effect is the stop of LH and FSH secretion, incorrect.
• Answer: b. un arrêt de la sécrétion de FSH et de LH

Question 16

• Explanation: LH (Luteinizing Hormone) and FSH (Follicle - Stimulating Hormone) are gonadotropic hormones (gonadostimulines) and they are proteins (glycoproteins) in nature. They are released from the anterior pituitary (not the pituitary stalk).
• Option a: Gonadolibérines are GnRH, not LH and FSH, incorrect.
• Option b: Correct, LH and FSH are gonadostimulines (gonadotropic hormones).
• Option c: Correct, LH and FSH are protein - like (glycoprotein) in nature.
• Option d: LH and FSH are released from the anterior pituitary, not the pituitary stalk, incorrect. So options b and c are correct. But if we have to choose one, option b is more about their function category.
• Answer: b. des gonadostimulines

Question 17

• Explanation: The secretion of FSH and LH in adults is regulated. It is permitted by the pulsatile secretion of GnRH. Testosterone has a negative feedback effect on LH and FSH secretion.
• Option a: Correct, the secretion of FSH and LH is regulated.
• Option b: Their secretion is not continuous and increasing, incorrect.
• Option c: Correct, the pulsatile secretion of GnRH is necessary for the normal secretion of FSH and LH.
• Option d: Testosterone inhibits their secretion, not permits, incorrect. So options a and c are correct. But if we consider the main regulatory factor, option c is more specific.
• Answer: c. permise par la sécrétion pulsatile de GnRH

Question 18

• Explanation: The hormonal regulation of male reproductive function involves a series of hormones: GnRH, LH, FSH, testosterone, and inhibin. It also involves positive and negative feedback controls. It is not an automatic mechanism, and it starts before birth.
• Option a: Incorrect, it is not an automatic mechanism, it is regulated by hormones.
• Option b: Correct, the hormones involved are GnRH, LH, FSH, testosterone, and inhibin.
• Option c: Incorrect, it starts before birth.
• Option d: Correct, it involves positive and negative feedback controls. So options b and d are correct. But if we have to choose one, option b is more about the hormones involved.
• Answer: b. fait intervenir des hormones qui sont : la GnRH ; la LH ; la FSH ; la testostérone et l’inhibine

Question 19

• Explanation: Hypophysectomy (removal of the pituitary) will lead to the lack of LH and FSH secretion. Since LH and FSH stimulate testicular hormone secretion (testosterone), hypophysectomy will cause a drop in testicular hormone secretion.
• Option a: Correct, hypophysectomy will cause a drop in testicular hormone secretion.
• Option b: Incorrect, without LH and FSH, testosterone secretion will decrease, not increase.
• Option c: Incorrect, GnRH secretion is regulated by testosterone feedback, without pituitary, testosterone will decrease, so GnRH secretion may increase, not decrease.
• Option d: Incorrect, as explained above, GnRH secretion may increase, not decrease.
• Answer: a. une chute des sécrétions des hormones testiculaires

Question 20

• Explanation: Ablation of the testes will lead to a decrease in testosterone secretion. Due to the negative feedback mechanism, the lack of testosterone will lead to an increase in the secretion of hypothalamic GnRH and pituitary LH and FSH (gonadotropic hormones).
• Option a: Incorrect, the secretion of pituitary gonadotropic hormones (LH and FSH) will increase, not decrease.
• (There are no other options fully shown, but based on the principle, the correct effect should be an increase in LH and FSH secretion due to the lack of testosterone negative feedback.)