Chapter 9 Endocrine System and Adolescence
Introduction
The word ‘adolescence’ comes from the Latin word ‘adolescence’ which means ‘to grow’. Adolescence describes the teenage years between 13 and 19 and can be considered the transitional stage from childhood to adulthood.
However, the physical and psychological changes that occur in adolescence can start earlier, during the preteen years (ages 9 through 12).
Adolescence can be a time of both disorientation and discovery. The transitional period can bring up issues of independence and self-identity.
Physiological changes in adolescence:
- Enhanced growth and development
- Changes in attitude, appearance, and personality
Hormonal changes inside the body Behavioural changes in adolescence:
- Enhancement of thinking ability encompassing future thinking.
- Sharing of social responsibilities
- Actions are mostly driven by ideas but not reasons.
- Transitioning from one period to another always is associated with some problems. Adolescence is not an exception and it is also associated with some problems.
Read And Learn More WBBSE Notes For Class 8 School Science
Puberty and Adolescence
Puberty is the time in which a child’s sexual and physical characteristics mature. It occurs due to hormone changes. Adolescence is the period between puberty and adulthood.
Puberty is a period of physical transition; adolescence is about a psychological and social transition. Puberty is the process of physical changes by which adolescents reach sexual maturity, i.e., become capable of reproduction.
WBBSE Class 8 Endocrine System notes
The various changes which occur in boys during puberty:
- Growth of hair on face and chest.
- Deepening of voice
- Spermatogenesis starts
- The body becomes muscular with the rapid increase in height.
- Feelings and sexual drives associated with adulthood begin to develop.
The various changes which occur in girls during puberty:
- Breasts develop and enlarge
- Ovulation and menstruation start
- Hips become wider.
- An increase in height occurs
- Feelings and sexual drives associated with adulthood begin to develop.
Hormones and Endocrine Glands
What exactly are hormones and how are they different from “non-hormones”? Hormones are chemical messengers secreted into the blood or extracellular fluid by one cell that affect the functioning of other cells.
Most hormones circulate in the blood, coming into contact with essentially all cells. However, a given hormone usually affects only a limited number of cells, which are called target cells. A target cell responds to a hormone because it bears receptors for the hormone.
What is a gland? A gland is an organ in the human or animal body that secretes hormones or chemical discharge internally or externally for different body activities.
There are two types of glands in our body:
- Endocrine gland
- Exocrine gland.
Glands that do not have any ducts or tubes are called endocrine glands. Endocrine glands secrete hormones, which are chemical “messengers” that travel through the blood to regulate the activity of a target organ.
Examples: Pituitary gland, Thyroid gland, Adrenal gland, etc.
Glands that have ducts are called exocrine glands. The secretions of exocrine glands reach their target by traveling through a duct (tube).
Exocrine glands are not part of the endocrine system. Some examples of exocrine glands are sweat glands and salivary glands. There are some glands that are both endocrine and exocrine in nature. These are called mixed glands.
Pancreas is a mixed gland. The endocrine part secretes major hormones of the body and the exocrine part creates pancreatic enzymes which are needed for digestion.
Endocrine System
The foundations of the endocrine system are the hormones and glands. As the body’s chemical messengers, hormones transfer information and instructions from one set of cells to another.
Although many different hormones circulate throughout the bloodstream, each one affects only the cells that are genetically programmed to receive and respond to its message.
Endocrine glands and their functions for Class 8
Understanding adolescence and hormones for Class 8
Hormone levels can be influenced by factors such as stress, infection, and changes in the balance of fluid and minerals in the blood.
The major glands that make up the human endocrine system are the hypothalamus, pituitary, thyroid, parathyroids, adrenals, pineal body, and reproductive glands.
The pancreas is also part of this hormone-secreting system, even though it is also associated with the digestive system because it also produces and secretes digestive enzymes.
Although the endocrine glands are the body’s main hormone producers, some non-endocrine organs — such as the brain, heart, lungs, kidneys, growth and the development of the brain and liver, thymus, skin, and placenta — also produce and release hormones.
Hypothalamus
The hypothalamus, a collection of specialized cells that are located in the lower central part of the brain, is the primary link between the endocrine and nervous systems.
Nerve cells in the hypothalamus control the pituitary gland by producing chemicals that either stimulate or suppress hormone secretions from the pituitary.
Pituitary Gland
Although it is no bigger than a pea, the pituitary gland, located at the base of the brain just beneath the hypothalamus, is considered the most important part of the endocrine system.
It’s often called the “master gland” because it makes hormones that control several other endocrine glands.
The production and secretion of pituitary hormones can be influenced by factors such as emotions and seasonal changes.
To accomplish this, the hypothalamus relays information sensed by the brain (such as environmental temperature, light exposure patterns, and feelings) to the pituitary.
The tiny pituitary gland is divided into two lobes: the anterior lobe and the posterior lobe.
The anterior lobe regulates the activity of the thyroid, adrenals, and reproductive glands. Among the hormones it produces are:
- Growth hormone,
- Prolactin
- Adrenocorticotropic hormone (ACTH),
- Thyroid-stimulating hormone (TSH),
- Luteinizing hormone (LH),
- Follicle-stimulating hormone (FSH).
The other lobe of the pituitary gland is called the posterior pituitary which controls different physiological functions of the body, it produces the following two hormones:
- Oxytocin,
- Antidiuretic hormone (ADH) or vasopressin.
The pituitary also secretes endorphins, chemicals that act on the nervous system to reduce sensitivity to pain. In addition, the pituitary secretes hormones that signal the ovaries and testes to make sex hormones. The pituitary gland also controls ovulation and the menstrual cycle in women.
The posterior lobe of the pituitary releases antidiuretic hormone, which helps control body water balance through its effect on the kidneys and urine output; and oxytocin, which triggers the contractions of the uterus that occur during labor.
Pineal Gland
The pineal body, also called the pineal gland, is located in the middle of the brain. It secretes melatonin, a hormone that may help regulate the wake-sleep cycle.
Thyroid and Parathyroids
The thyroid, located in the front part of the lower neck, is shaped like a bow tie or butterfly and produces the thyroid hormones thyroxine and triiodothyronine.
These hormones control the rate at which cells burn fuels from food to produce energy. As the level of thyroid hormones increases in the bloodstream, so does the speed at which chemical reactions occur in the body.
Thyroid hormones also play a key role in the bone nervous system in children. The production and release of thyroid hormones is controlled by thyrotropin, which is secreted by the pituitary gland.
Attached to the thyroid are four tiny glands that function together called the parathyroids. They release parathyroid hormone, which regulates the level of calcium in the blood with the help of calcitonin, which is produced in the thyroid.
Adrenal Glands
The body has two triangular adrenal glands, one on top of each kidney. The adrenal glands have two parts, each of which produces a set of hormones and have a different function.
The outer part, the adrenal cortex, produces hormones called corticosteroids that influence or regulate salt and water balance in the body, the body’s response to stress, metabolism, the immune system, and sexual development and function.
The inner part, the adrenal medulla, produces catecholamines, such as epinephrine, also called adrenaline.
Adrenaline is a hormone secreted by the adrenal medulla during stress.
WBBSE Chapter 9 summary on endocrine system
This is called emergency growth of facial and pubic hair, and hormones because it initiates a quick reaction that makes the individual think and respond quickly to stress.
The hormone increases metabolic rate. There occurs dilatation of blood vessels going to the heart and the brain. The blood vessels reaching the skin and kidneys constrict in order to provide more blood to the heart and the brain.
They also increase fat metabolism thereby synthesizing more energy. The word adrenaline is used in common parlance to denote increased activation of the sympathetic system associated with the energy and excitement of the fight-or-flight response.
Pancreas
The pancreas produces (in addition to others) two important hormones, insulin, and glucagon. They work together to maintain a steady level of glucose, or sugar, in the blood and to keep the body supplied with fuel to produce and maintain stores of energy.
Gonads or Reproductive Glands
The gonads are the main source of sex hormones. In males, they are located in the scrotum. Male gonads, or testes, secrete hormones called androgens, the most important of which is testosterone.
These hormones regulate body changes associated with sexual development and the appearance of other male secondary sex characteristics such as the deepening of the voice and the increase in muscle growth and strength.
The female gonads, the ovaries, are located in the pelvis. They produce eggs and secrete the female hormones estrogen and progesterone. Estrogen is involved in the development of female sexual features.
Both estrogen and progesterone are also involved in pregnancy and the regulation of the menstrual cycle.
Table -1 Table of Endocrine glands, their hormones, and the action of the hormone
Functions of hormones in adolescence Class 8
Problems with The Endocrine System
Too much (hyperfunction) or too little (hypofunction) of any hormone can be harmful to the body. For example, if the pituitary gland produces too much growth hormone, a child may grow excessively tall. If it produces too little, a child may be abnormally short.
Endocrine disorders are typically grouped into two categories:
An endocrine disease that results when a gland produces too much or too little of an endocrine hormone, is called a hormone imbalance.
Endocrine disease is due to the development of lesions (such as nodules or tumors) in the endocrine system, which may or may not affect hormone levels.
The following are just a few of the many disorders that can result from an improperly functioning endocrine system.
1. Gigantism (acromegaly) and other growth hormone problem: Acromegaly is a disorder in which the anterior pituitary produces too much growth hormone (GH).
This causes an increased growth in bone and soft tissue, especially in the extremities—nose, jaw, fingers, and toes. If the disorder occurs in children who have not yet fully developed, the increased levels of GH also result in the exceptional growth of the long bones. This condition, a variation of acromegaly, is known as gigantism.
2. Pituitary dwarfism: Pituitary dwarfism or growth hormone deficiency is a condition in which the pituitary gland does not make enough growth hormone. This results in a child’s slow growth pattern and unusually small stature (below average height).
3. Hyperthyroidism: Hyperthyroidism is a condition in which the levels of thyroid hormones in the blood are excessively high.
Symptoms may include weight loss, nervousness, tremors, excessive sweating, increased heart rate and blood pressure, protruding eyes, and swelling in the neck from an enlarged thyroid gland (goiter).
4. Hypothyroidism: Hypothyroidism is when the levels of thyroid hormones in the blood are abnormally low. Thyroid hormone deficiency slows body processes and may lead to fatigue, a slow heart rate, dry skin, weight gain, constipation, and, in kids, slowing growth and delayed puberty.
5. Diabetes mellitus: Disorder in which the body’s cells cannot absorb glucose, either because the pancreas does not produce enough insulin or the cells do not respond to the effects of insulin that are produced. It has two types.
Type-1 Diabetes:
When the pancreas fails to produce enough insulin, type 1 diabetes (previously known as juvenile diabetes) occurs. Type 1 diabetes can cause long-term complications, including kidney problems, nerve damage, blindness, early coronary heart disease, and stroke.
To control their blood sugar levels and reduce the risk of developing diabetes complications, kids need regular injections of insulin.
Type-2 Diabetes :
Unlike type 1 diabetes, in which the body can’t produce normal amounts of insulin, in type 2 diabetes the body is unable to respond to insulin normally.
Children and teens with this condition tend to be overweight, and it is believed that excess body fat plays a role in the insulin resistance that characterizes the disease.
Hormonal changes during adolescence for Class 8
6. Adrenal insufficiency: This condition is characterized by decreased function of the adrenal cortex and the consequent underproduction of adrenal corticosteroid hormones.
The symptoms of adrenal insufficiency may include weakness, fatigue, abdominal pain, nausea, dehydration, and skin changes.
7. Addison’s disease: Disorder in which the adrenal cortex underproduces cortisol and aldosterone, resulting in the disruption of numerous bodily functions.
8. Cushing syndrome: If the condition is due to a tumor in the pituitary gland that produces excessive amounts of corticotropin and stimulates the adrenals to overproduce corticosteroids, it’s known as Cushing’s disease.
Symptoms may take years to develop and include obesity, growth failure, muscle weakness, easy bruising of the skin, acne, high blood pressure, and psychological changes. Moon face- a rounded shape of the face that develops from a specific pattern of fat distribution.
9. Precocious puberty: Body changes associated with puberty may occur at an abnormally young age in some kids if the pituitary hormones that stimulate the gonads to produce sex hormones rise prematurely.
10. Polycystic ovary syndrome: Overproduction of androgens interfere with the development of eggs and their release from the female ovaries. PCOS is a leading cause of infertility.
Adolescent Development
A critical and rapid transition
WHO identifies adolescence as the period in human growth and development that occurs after childhood and before adulthood, from ages 10 to 9.
It represents one of the critical transitions in the life span and is characterized by a tremendous pace of growth and change that is second only to that of infancy.
Biological challenges as young people transition from childhood to adulthood. It can seem like teens have processes that drive many aspects of this growth and development,
The onset of puberty marks the passage from childhood to adolescence. The biological determinants of adolescence are fairly universal;
however, the duration and defining characteristics of this period may vary across time, cultures, and socioeconomic situations.
Key developmental experiences
The process of adolescence is a period of preparation for adulthood during which time several key developmental experiences occur.
Besides physical and sexual maturation, these experiences include movement toward social and economic independence, and development of identity, the acquisition of skills needed to carry out adult relationships and roles, and the capacity for abstract reasoning.
While adolescence is a time of tremendous growth and potential, it is also a time of considerable risk during which social contexts exert powerful influences. one foot in childhood and one in adulthood as they navigate the changes in their bodies and minds.
Some of the normal changes going on for teens
- With the onset of puberty, preteens and teenagers experience rapid growth and changes in their bodies, develop sexually, and become increasingly aware of their body image.
- Teens develop their own morals, values, and self-direction; they test limits and try on different points of view; they develop a conscience.
- Social skills continue to develop and include romantic relationships.
- Teens have an increased awareness of self, which can include feeling self-conscious and fluctuating high or low self-esteem,
- Teens continue to develop cognitively, with an increased capacity for problem-solving, decision-making, and abstract thinking;
- however, their thinking is still more impulsive than adults; for example, the mere presence of peers can encourage them to engage in risky behavior.
Changes during Adolescence
Physical
- Physical changes (e.g., growth spurt and skeletal and structural changes) are rapid and visually apparent.
- Considerable diversity in physical developmental rates occurs due to genetics, environmental factors, and health issues.
- Distinct gender differences are evident in size, strength, and age of growth spurt (e.g., girls around age 12 and boys around age 14).
- Self-esteem changes due to adolescents’ home and school lives.
- Preoccupations with the self lead to critical self-examination and subsequently to the formation of self-perceptions.
- Argumentative and aggressive behaviors become evident and often disturb parents and teachers.
Psychosocial
- Friendships form and social interactions increase, which have the potential for boosting self-esteem and reducing anxiety.
- Distinct gender differences occur in socialization patterns (e.g., females tend to have smaller numbers of close friends and males tend to have larger “social networks”).
- Allegiance and affiliation shift from parents and teachers to friends and peers.
- Social tasks and situations are handled without adult supervision and advice.
Cognitive
- Higher levels of cognitive functioning (e.g., reasoning and higher-level thought processes) develop.
- Moral and ethical choices are now possible and often guide behavior.
- Development diversity leads to varying abilities to think and reason.
- Cognitive ability is often affected by overall socialization.
- Perspectives about past, present and future developments that allow enhanced perspectives of time.
- Language and overall verbalization skills increase, allowing improved communication in both school and home situations.
Significance of Adolescence Stage
Adolescence is a significant period because it is a period of:
1. Rapid physical development
It is a period of vital physical as well as physiological changes and developments. At this stage, all the external and internal body parts and organs achieve their full form and maturity.
2. Rapid mental development
During the early adolescence period, rapid mental development occurs. These give rise to the need for later mental adjustments and the necessity for establishing new attitudes, values, and interests.
The adolescent is mentally alert at this stage. He not only develops his intellectual power but also his capacity to critical thinking.
3. Rapid social development
It is a period of social development and adjustment. In this stage, the child enters a new field of social responsibility. The adolescents become socially conscious, self-assertive, and loyal towards their group; they develop cooperation and friendship and become responsible.
4. Stage of emotional development
Traditionally adolescence has been thought of as a period of heightened emotionality resulting from glandular and other changes. The heightening is characterized by a high degree of instability.
Importance of the endocrine system in growth Class 8
The adolescents also develop dependency and sometime independency. They also develop some special feelings like – pride, humility, curiosity, guilt, hero-worshipping, etc.
All these emotions must be properly guided and they should be provided knowledge to control their emotions at this stage.
5. Rapid sexual development
A number of internal and external changes take place in the sexual characteristics of boys and girls during the adolescence stage. In the later part of this stage, they achieve sexual maturity.
6. Rapid moral development
It is also a period of moral development and changes in morality. Their moral outlook becomes progressively more abstract. Moral convictions become more concerned with ‘what is right’ and justice emerges as a dominant moral force.
Their moral judgment becomes less egocentric at this stage. They develop an attitude towards service to mankind.
Problems of Adolescence Stage
The problems of adolescence may be summarized in the following manner:
1. Sex Problems
We have read that all the aspects of adolescent development are basically conditioned by physical changes. The onset of puberty gives the physical excitement never experienced before.
The adolescent reacting to these experiences is excited, often without realizing what is happening to him. Some react with pleasure or excitement and some others experience shame, disgust, confusion, anxiety, and guilt. They may lead to sexual maladjustment.
2. Emotional Problem
Heightened emotionality is a major problem of adolescence. Adolescents experience excessive emotion and they do not have sufficient control over violence.
Excitability and anger may find expression in their destructive form and may lead to law and order problems. The emotion of love, suspicion, jealousy, frustration, and revengefulness is very common among adolescents. Thus emotional immaturity is a major problem in adolescence.
3. Social Problem
Every society has its own customs and traditions, which it wants to maintain. Every individual has to follow these social values but often adolescents think all these are outdated and they are not willing to obey
This leads to conflicts. Physical development has many social implications. Sexual development necessarily includes heterosexual orientation and they want to take part in social activities with the opposite sex.
The denial of this desire often makes them discontented and restless. Drug addiction is a major social problem during adolescence.
Drugs are powerful chemicals that when taken into the body change the functions of the body, influence the mind, and therefore, sometimes even change the behavior of the person.
Adolescent boys and girls should avoid drugs to maintain physical, mental and social well-being which are necessary to live a purposeful, fruitful, and satisfying life in this world. Thus, a number of social problems disturb adolescents.