Development of the Human Reproductive Organs

All human beings have numerous skeletal and muscular dimension changes that are common during their adolescence. The time duration for attaining puberty in male and female are different. But changes undergone during puberty are common. Approximately, male puberty occurs at the age of 10-15 years with the initial sign of accelerating penis growth. The spurts height and penis development cannot be noticed among certain boys till the entire early maturity is completed. Girls will usually come under adolescence at the age of 11 - 13 years. 

Boy’s tempo development mainly depends on the psychological and social infrastructure. The person with advanced development of secondary sex characteristics and the human reproductive system will have contemporaries in athletic and sexual interest together. The development of secondary sex characteristics and the human reproductive system requires different time periods for both males and females. 

Changes During Male Puberty 

The development of the reproductive organs and secondary sex characteristics creates notable changes among boys. The first sign of male puberty is the acceleration of the growth of the testes and scrotum with reddening and wrinkles on scrotal skin. It begins to grow slight public hair and begins to develop later. The changes in spurts height and penis growth start growing after a year of initial puberty sign. After certain changes, the seminal fluid starts secretion from the enlarged and developed penis. 

Axillary hair starts growing after two years of public hair growth. The axillary hairs start appearing on the face as moustaches and beards. All these depend on the hormone secretion and variation of organs. Voice-breaking is common at the late stages of adolescence. This is mainly due to the enlargement of the larynx and increasing the length of vocal cords, it is because of testosterone hormone on laryngeal cartilages. This is most common for both male and female adolescence.  This also causes the enlargement of resonating spaces, which results in the rapid growth of the mouth, nose, and maxilla.

The sebaceous and apocrine sweat glands will grow faster in the skin of armpits and genital and anal regions and raises their odour characteristics while attaining puberty. These changes are common among both males and females. Enlargement of root pores on the nose appears as comedones and acne. The androgenic activity is responsible for skin colour changes. The adolescent male breast also undergoes some permanent and temporary changes. 

Changes During Female Puberty

The diameter of the areola is equal for both sexes before puberty, it starts to enlarge after the midway of adolescence.  Breast enlargement and breast bud can be noted as the first sign of puberty in girls, along with the appearance of pubic hair. Along with the breast, other parts like the labia, clitoris, uterus, and vagina also start developing in its size. The first menstrual period is known as menarche. It represents the mature stage of uterine development. But it does not attain the entire structure for reproductive function. Some girls can find irregularities during the early cycles. It may be due to an anovulatory process. This may take 18 months after the menarche. On average, girls grow 6cm it is about 2.4 inches after menarche, which may double depending on the individual. After the first sign of puberty, it takes 18 - 6 years to complete the maturity of the uterus. For completing the entire development of secondary sex characteristics and the human reproductive system in females, it takes a minimum of 6 months to 66 months. 

Sex Dimorphism 

The differentiation among sex partially occurs in the fetal stage. The development of the reproductive organs and secondary sex characteristics also makes wide differential effects on the growth of bone and muscles. During puberty, the fat in the body plays a major role to differentiate its size.  While attaining puberty, boys’ breadth of the shoulder increases as girls width of the hips.  Girls pelvic outlet gets wider during birth, but pelvic shape alters during puberty. 

Physical and Behavioral Interaction

The changes in baby growth are common at all stages but can note the drastic changes during adolescence. This shows the difference between developmental age and chronological age. Every individual has a different path and span of maturity. The span of maturity is less among girls, while compared to boys. Skeletal maturity majorly occurs during adolescence, it determines sex characteristics among individuals. The range of chronological age stays between 10 - 16.5 years, the corresponding bone age varies from 12 - 14.5 years. 

Hormone Changes and Growth  

The development of secondary sex characteristics and the human reproductive system mainly occurs due to the hormonal changes and secretion of hormones. The major hormones are Pituitary growth hormone, thyroid hormone, pituitary gonadotropic (sex-gland-stimulating) hormones, sex hormones like testosterone and estrogen. 

Pituitary gland secretes pituitary growth hormone throughout human life, which contains amino-acid composition and protein with a molecular weight of 21,600. The pituitary growth hormone plays a predominant role in child growth, lack of it may result in dwarfism. The secretion of growth hormone from the pituitary is controlled by the brain and secrets according to current needs.  This hormone decreases fat and lays protein on the muscles to promote growth.

Thyroid gland in the neck secrets thyroid hormone, which is necessary for the normal growth of human beings. It assists to stimulate pituitary hormone. It helps cell development and functions.  Babies with a lack of thyroid hormone have insufficient brain development. It may slow down the growth of baby development. 

Testis cell secretes testosterone. It is not only responsible for puberty, it takes responsibility for the development of male genital apparatus during the earlier stage. If the testosterone fails to secrete at a particular time, the genitalia develops into a female form. Only a small quantity of testosterone will circulate the body and makes it responsible for numerous growth during puberty. 

Estrogen is a female sex hormone, which starts secret from ovary cells at the initial stage of puberty. This helps for the growth of the uterus, vagina, and breast. It is responsible for the widening of hip bones in females. 

The follicle-stimulating hormone from the pituitary gland takes responsibility for the ovary in female and sperm-producing cells in the male.  Luteinizing hormone secreted by the pituitary gland causes the growth of testosterone-secreting cells in males and controlling the menstrual activities in females.