Adolescence is that period of the human development that occurs during the time span between childhood and adulthood. More specifically, it spans from 10 to 19 years. Apart from physical and sexual changes, adolescence also marks the beginning of more independent attitude in maturing girls and boys as they move towards creating their unique identity.The human body undergoes both physiological and mental changes during adolescence. Thus changes occur in parts of body including brain, sexual organs during this period. The growth spurt is observed in puberty, characterized by rapid growth in extremities such as hands, head and feet fallowed by legs,arms, torso and shoulders.This gives an adolescent body an out of proportion look.In adolescents the rate of growth nearly becomes equal to growth of a child.
The male and female sexual development is governed by two different hormones viz. testosterone and estrogen respectively. Prior to explaining the two, it is important to study a frequently used term in adolescence development called androgens.
Androgens are produced by the adrenal glands and ovaries in females. In males, androgen is produced by testis. Androgens provide for the activity of accessory sex organ .Androgens also help in the development of secondary sexual characteristic. Secondary sexual characteristics show that a child has grown into an adult. Some of the visible secondary sexual characteristics are appearance of Adam’s apple and facial hair in males and enlargement of breasts in females. The natural male androgen is testosterone and natural female androgens are estrogen/oestrogen and progesterone.
Testosterone is a natural androgen found in human males (androgens can also be synthetically made). Chemically, testosterone is C 10 sterol compound. This hormone is synthesized by the interstitial cells of the testis .Testis are two flat and oval bodies, found one on each side of the scrotum sac beneath the penis. Interstitial cells from the endocrine part of the testis.
Physical changes in boys during adolescence
Testosterone acts to cause growth of accessory male sex organs like testis and penis, the seminal vesicles, vas deferens, prostate, epididymis etc. testosterone also facilitates sperm production. The hormone exerts myotrophic effect and helps in muscular development of certain muscles. Testosterone also provides for normal development of secondary sexual characteristics. Secondary sexual characteristics exhibited by human males by action of testosterone are listed below.Growth of facial, body, underarm, abdominal, chest and pubic hair.
Androgenic alopecia can cause loss of scalp hair.Boys usually complete puberty changes between 16 to 17 years.
1.Ejaculation of semen through penis starts. Ejaculation due to spontaneous orgasm during sleep (Wet dreams) nocturnal emissions becomes common.
2.Deepening of voice as a result of enlargement of larynx or Adam’s apple.
3.Development of facial hair like mustache and beard, body hair like hair on chest, hands, legs and Pubic hair in the groin.
4.Heavier bone structure and skull, increase of mass of thigh muscles located in front of the femur
5.Thinning of waist.Increased muscle mass and strength , enlarged body and stature along with squaring of face.
6.Growth of penis and enlargement of testis.
7.Rapid growth and increase in height (growth spurt) with lower body fat percentage.
8.Widening of shoulders and chest.
9.Increase in sweat and oil secretion from the body causing body odor and acne formation.
Physical changes in girls during adolescence
Progesterone and oestrogen/estrogen constitute female sex hormones.
Oestrogens or estrogen are sterol derivatives. They are secreted by the Graafian follicles, corpus luteum, placenta and interstitial cells found in ovaries. Oestradiol and oestriol constitute oestrogens. Oestrogen is responsible for all the puberty changes that occur in females. The puberty changes include growth of vagina, uterus and stratification, of vaginal epithelial cells. Oestrogen proliferates the ducts of the breast and causes Breasts enlargement. The hormone also causes increases in secretions of fallopian tubes. Oestrogen is responsible for proliferative changes in menstruation. Oestrogen also develops secondary sexual characteristics in female. Girls usually complete puberty changes between 15 to 17 years.Progesterone in females is secreted by the corpus luteum, placenta and adrenal cortex. The hormone is a sterol derivative having a side chain at the 17 C position. Progesterone causes an in vaginal cellular proliferation and acts synergistically with oestrogens to cause development of secondary sexual characteristics in females. Progesterone is responsible for premenstrual changes that occur in uterine mucosa. The hormone causes an increase in ovulation and causes enlargement of breasts.
1.Secondary sexual characteristics appear in females because of the female androgen estrogen.
2.Erection of nipples and enlargement of breasts occurs between 8-13 years.
3.Growth of the pubic hair occurs between 8- 14 years and underarm hair fallows after two years . Pubic hair starts growing first along the lips of vagina in the shape of inverted triangle and gradually grow in to thighs.
4.Increase in thigh muscle behind the femur (opposite to males).
5.Increase in width of hips resulting in a lower waist to hip ratio than males.
6.Growth of uterus, the inner lips of vulva, clitoris and labia minora show color change.
7.Increase in length of upper arms.Rounding of face.
8.Menstrual cycle starts between 10 -16 years.
Stages of Adolescence
Adolescence occur in three stages namely Early adolescence (12-14 years), Middle adolescence (15-17 years) and Late adolescene (18-21 years).
During early adolescence the youngsters tend to remain moody, more aware about their body changes and compare their body physique with idealized personalities. They develop shyness and crave for privacy. They express their inner emotions non verbally in spite of poor communication skills. Fantasies, day dreaming are common.
Middle adolescents invest lot of time in self grooming, body shaping and experimenting with new hair styles. Imitating the mannerisms and gestures of their favorite role models (Hero worship) is frequently observed. They imagine themselves as well grown adults with self concepts and esteem and often dislike parent's interference with their freedom and privacy.Risky behavior like trying alcohol, Cigarettes, drugs and intercourse develop during this stage. Speaking skills develop consistently and begins better use of verbal communication. There are more chances to contract HIV and STDs because of emotional ignorance at this stage.
Late adolescents eventually turn into responsible young adults. They recognize and respect the suggestions of their elderly parents. They stay focused in achieving career goals and start a family. Maximum mental maturity is observed in this stage. They avoid risky behavior and pay little interest in grooming. Becomes acclimatized to ways of life, pleasure and pain and develops compromising nature. Becomes more concerned about serious relationships.
Main health issues during adolescence
Adolescence has its own set of health issues. The major heath issues are early pregnancy has complications and can cause death of both mother and fetus. Birth control pills, procedures and techniques provide solution to this menace.Lack of knowledge about sexual diseases like HIV leads to their spread. Caution during sexual activities like use of condoms provides some relief. Other HIV control measures such as not using used syringes, infected blood etc must be practices. Spread of education in masses regarding STDs can eradicate these diseases.
Depression is one of the leading causes of suicidal death in adolescent individuals. Hunger, violence, poverty and other causes are related to depression. Counseling is one of the measures for treating depression. Drugs are also available.
Androgen related disorders
Low androgen levels cause decrease in interest for sex, bone diseases, fatigue and decrease in sense of well being. Low androgens levels in females mostly occur during menopause. Low androgen levels are treated with estrogen containing medications.High levels of female androgens cause hirsutism, acne and thinning of hairs. High levels of female androgens can also cause PCOS or poly systic ovary syndrome. PCOS results in infertility, irregular or totally absent menstrual periods and blood sugar disorders.Hyperandrogenism can also cause a genetic disorder called. Congenital adrenal hyperplasia. Other adrenal abnormalities can also occur. Ovarian tumors are also formed in some cases.
Acne a big problem in adolescence
Adolescents mostly experience acne on their face, neck, back, chest and shoulders. Acne spoils self esteem and appearance and that is what most teenagers are bothered about. The reason for these pimples is elevated levels of androgen hormones in body stimulates Oil glands (Sebacious glands) in skin. These glands become hyper active and secrete oily substance called Sebum which usually comes out from hair follicle, but excess amounts of sebum clog the follicle passage and soon attracts bacteria around to thrive on it. This causes infection, pus accumulation causing a swelling. Some times these pimples burst and leave permanent ugly scars on skin.
General treatment of acne include Ointments, creams and lotions with formulations of salicylic acid, benzoyl peroxide. Mild form of acne can be treated with benzoyl peroxide,tazarotene, adapalene, dapsone, azelaic acid and antibiotics. Doctors may prescribe oral antibiotics to inhibit the bacterial growth on skin. It is advised to take two gentle face washes per day with mild soap. Too much cleansing of face should be avoided as it may irritate skin and trigger the activity of oil glands, making the situation much more worse. Squeezing the pimples may push bacteria into deeper layers of skin so, it is better to stop it.
Changes in the Brain during adolescence
The human brain reaches 90% of its size during the first 6 years of life. During the years 10 to 25, the brain undergoes those changes that are important for behavior. The creases of the brain start taking a complex shape during the late teen age. Changes in folds of brain cortex during adolescence result in the cognitive and emotional improvements. During adolescence, the white matter content of the brain increases. Synaptic pruning also occurs which is the elimination of unnecessary neuronal connections. Increase in myelination makes the brain more efficient. Both synaptic pruning and myelination that occur in the prefrontal cortex improves the efficiency of the brain in processing information. The brain also evaluates “risks and rewards "in a better way as the neural connections in brain (specially the prefrontal cortex) get strengthened. “Planning ahead” functions are created by developments that occur in the dorsolateral prefrontal cortex. Decision making gets improved as the ventromedial prefrontal cortex develops further.Various neurotransmitters are involved in adolescent brain functioning. Glutamate is secreted during synaptic pruning. Dopamine effects decision making, risk taking and boredom. Serotin effects “rewards and punishment”, mood and behavior.
Cognitive development during adolescence
Cognitive development includes reduction in egocentric thoughts and start of occurring of more abstract forms of thought. Thus during adolescence an individual starts to think in wider terms. These functions are associated with prefrontal cortex. The cognitive developments play a major role in forming character and personality.Other cognitive developments are improvement in attention, memory (both working and long term), faster processing of knowledge and information, organization and metacognition or thinking about self.Considerable improvement in selective attention-ability to focus on one stimulus and divided attention - ability to focus on more than one stimuli simultaneously are observed.
Psychological development during adolescence
During adolescence the individuals start to form their own beliefs and values. They set aim for the rest of their life. During this period the individual gets highly self conscious. The children start to lose parental control and began experimenting with new ideas. It is important that the newly turned adolescents use their newly acquired skills to gain self confidence. The adolescent takes more control of the vocational and educational aspects of his/her life. The adolescent strive for self interdependence and self esteem. During late stages of adolescence an individual feels psychologically integrated and develops a consistent view of the outside world. The individual concludes the adolescent stage by setting goal and aspirations and starts to work for them in his/her later periods of life.
They tend to develop self-esteem and self-concepts to gain recognition in society and among peers. They spend much time in personal grooming, making them selves look presentable.They tend to stay updated in fashion clothing, hair styling, stylish mannerisms and accent to mark their identity.Girls make efforts to look charming and presentable, spend much of their time before dressing table in applying cosmetics, hair styling etc. It is during this age most of the girls choose modeling as their career.
Love, romance and sexual behavior
Because of heightened attractions towards opposite sex, the adolescents fall in love with each other. They become overwhelmed in infatuations and day dreams. They spend most of time, texting and love making. Adolescents often date with their class mates and same age group and tend to hang around in pairs in social gatherings. Holding hands and staring in each other's eyes, lip kissing, hugging are some romantic events in adolescents. Sexual intercourse is less pronounced and often some adolescents make a try to explore it.
There is difference between youth and adolescence. Youth fail to understand the implications of their behavior. Adolescents do not fully understand the implications of their behavior though they have some understanding of it. The adults can fully comprehend the implications of their behavior. In adolescence the judging power of the brain is not fully developed. Thus adolescent’s behavior may include inappropriate sexual, health and other decisions. Also, the fast maturing body may fail to fully control itself that may cause rash or inappropriate behavior.
Family, school and community provide the required support that may help the individual to successfully undergo the transition from childhood to adulthood. It is the duty of parents, guardians, teachers to provide key support to the young adults to learn right skill and acquire right knowledge during this period.
Hormones involved in adolescent growth
The growth in humans is associated with many hormones. These include the pituitary growth hormone, the thyroid hormone, sex hormones viz. estrogen and testosterone and the sex gland stimulating hormones or the pituitary Gonadotrophic hormones.
Pituitary growth hormone or human growth hormone (HGH)
The pituitary gland is an endocrine gland located in the brain. The gland secretes many hormones and the hormone that is concerned with growth is the growth hormone or Somatotrophic hormone.
The growth hormone or HGH has a molecular weight of approximately 21000 daltons. This hormone is a crystalline protein. The human GH consists of a straight chain polypeptide structure having 2 disulphide bridges. The human HGH contains around 188 amino acids. The human growth hormone has growth stimulating as well as lactogenic effects.
Actions of human growth hormone or HDH
The hormone increases the length of the cartilage bones by stimulating the multiplication of epiphyseal cartilage. The hormone exerts a direct influence of growth of tissues. It stimulates muscular growth and visceral growth. It also stimulates the growth of the thymus gland and stimulates secretion of milk during lactation period. It has no effect on growth of nervous system. If there is inadequate or no secretion of pituitary growth hormone then dwarfism occurs. Children who do not have HGH are fat. When HGH is secreted in them, they lose fat and gain height
The hypothalamic hormone GHRF or growth hormone releasing factor secreted by hypothalamus controls the secretion of HGH by the acidophil cells of the pituitary. It has been found that a sharp lowering in blood sugar level results in secretion of GHRF due to which HGH is released. The secretion of HGH results in increased mitotic activity of the thymus which is mediated by cyclic AMP.
Thyroxine or T3
The thyroid hormones are secreted by thyroid gland that is situated in the root of the throat. The thyroid gland secretes thyroxine hormone that is involved in both physical and mental growth. Thyroxine is also called T4 and chemically is an amino acid having chemical formula 3,5,3’,5’-tetraiodothyronine.Both HGH and thyroxine exert influence on the growth of tissues of body. The differentiation of growing is solely influenced by thyroxine. Thyroxine helps in the maturation and differentiation of epiphysis or skeletal muscles. Lack of thyroxine causes decreased muscular, gonad and brain growth which is called cretins.