HPE Exam

1.1 Introduction

Every part of the human body is made up of minute parts, which are called cells and intercellular substance which is produced by the cell. Thus, the smallest functional unit of a living being is called a cell. Each cell is so small that it can be seen only through a microscope. Each cell has three main parts. They are: the cell wall which surrounds and protects the cell; the protoplasm, a grayish jelly-like material, which is really the body of the cell; and the nucleus which is the life centre inside the body of the cell.

Cell membrane

Cytoplasm

Mitochondrion

Nuclear Membrane

Nucleus -Nucleolus

Each cell lives its own life. It grows and multiplies by dividing itself into two halves. The cells after the division form the group of cells and the group of cells having similar characteristics and functions is called a tissue. The body is made up of five types of tissues. Each serves a different purpose. Each reacts to different stimuli, e.g., the group of nerve cells form the Nervous tissue which works as the Nervous system. The tissues in their turn construct internal and external organs related -Vacoule with special functions. For convenience, the organs may be grouped to form the system. Thus, a group of organs having a specific function is called a system. Each system contributes to one or more of the vital functions of the body. For example, the digestive system consists of food pipe (oesophagus), stomach, intestine, etc. Thus, the system of organs related to chewing, swallowing, digesting and absorbing the food and finally discarding the unwanted food is called the digestive system. In the same way, the nose, trachea (wind pipe) and lungs form a group called the respiratory system which provides the route by which the supply of oxygen present in the atmospheric air gains entry into the body and provides the route of excretion of carbon dioxide. Besides this, there are some other systems for different functionIn fact, the body works with the help of individual cells, tissues, organs an various systems. Altogether, there are nine systems in the

(1) The Skeletal System

(11) human body. They are, The Muscular System

(ii) The Digestive System

(iv) The Respiratory System

(v) The Circulatory System

(vi) The Urinary System

(vii) The Glandular System

(viii) The Nervous System, and

(ix) The Reproductive System.

Among these systems, we will study the following systems in grade VIII

The Nervous System

The Glandular System

The Reproductive System

1.2 The Nervous System

Nervous system is the mechanism by which sensations of all kinds are received from the environment and from the tissues, and organs of the body. It is on account of this system that various organs of the body work in co-operation and co-ordination Nervous system is, in fact, a co-ordinated network of different systems. The functions of sensory organs (touch, taste, hearing) and the internal organs depend on the nervous system. The nervous system is formed of nervous tissue which is specially designed t receive stimuli from either inside or outside the body, and when stimulated, to carr impulses rapidly to other tissues. The nerve tissue is composed of nerve cells and nerve fibres, commonly known as neurones. On the basis of their functions, the neurones car be classified into:s of the body.Brain

Reflex a #

Spinal cord

Dendrites

Nerve cell

"Nucleus of nerve cell

-Peripheral nerves

Peripheral nerves

Axon

Fig. 13. General view of the brain and spinal cords

Fig. 14 A neurone

(i) Sensory or Afferent Nerves: These are the nerves which receive stimuli and transmit impulses from the periphery of the body to the spinal cord and brain.

(ii) Motor or Efferent Nerves: These are the nerve cells which transmit nerve

impulses from the brain or from the spinal cord to muscular or glandular tissues.

(iii) Mixed or Association Nerves: A connecting neurone usually serving as a link between two other neurones, is called a mixed or association nerve.

Parts of the Nervous system are

A. The Central Nervous System,

B. The Peripheral Nervous System, and

C. The Autonomic Nervous System.

A. The Central Nervous System

The central nervous system consists of the brain and spinal cord.Brain: The brain is the principal centre. It controls and directs the body. The mind is located in it. It is located within the skull and is protected from injury by the strong bones of the skull.

Mid brain

Pons varol Medulla oblongata-

-Cerebellum

It has the following main parts:

(1) Cerebrum,

spinal cord

(ii) Midbrain,

(iii) Pons varolii,

(iv) Medulla oblongata, and

(v) Cerebellum.

Fig. 15. The parts of the central nervous system

(i) Cerebrum: It is the largest part of the brain which is located within the skull and is protected from injury by the strong bones of the skull. The cerebrum is covered by the protective membranes called meninges. These meninges lie between the skull and the brain. Mental activities involved in memory, intelligence, thinking, reasoning, sensory perception, feeling of pain, temperature, touch, sight, hearing, smell, taste, control of voluntary muscle contraction, and other major activities are associated with cerebrum.

(ii) Midbrain: The midbrain is the area of the brain situated between the cerebrum above and the pons varolii below. The mid brain conveys the impulses passing to and from the brain and spinal cord.

(iii) Pons Varolii: The pons varolii is situated in front of the cerebellum, below the midbrain and above the medulla oblongata. The group of cells of the pons acts as a relay station and some of these are associated with the cranial nerves.

(iv) Medulla Oblongata: The medulla oblongata extends from the pons varolii above and is continuous with the spinal cord below. Medulla oblongata works as a relay station for sensory nerves passing from the spinal cord to the cerebrum. Vital centres of the medulla are associated with the control of autonomic reflex action, whereas cardiac centre controls the rate and force of cardiac contraction.

(v) Cerebellum: The cerebellum is situated behind the pons varolii and immediately below the posterior portion of the cerebrum. It is responsible for the co-ordination of muscular movement, maintenance of the bodily balance, control of muscle tone and maintenance of posture.

1Spinal Cord: The spinal cord is the elongated,

almost cylindrical part of the central nervous system, which is suspended in the vertebral canal surrounded by the imeninges and cerebro-spinal fluid. The spinal cord consists of 31 segments. Each segment of spinal cord corresponds to one pair of spinal nerves. There are altogether thirty-one pairs of spinal nerves. Spinal cord relays impulses coming in and going out at the same level. It communicates between the brain and all parts of the body. and works as a centre of reflex action.

Cervical nerves

Thoracic nerves

Lumbar nerves

Sacral and coccygeal nerves

-Spinal cord

End of spinal cord

-Cauda equina

Fitumterminale

B. Peripheral Nervous System

Fig. 16. The spinal cord and spinal nerves

This system consists of 12 pairs of cranial nerves, 31 pairs of spinal nerves and their various branches in body organs. Some nerves of the peripheral nervous system are composed of sensory nerve fibres (transmitting information to the central nervous system). Others are motor nerve fibres (carrying impulses from the brain), and mixed nerve fibres.

C. The Autonomic Nervous System

The autonomic nervous system controls the functions of the body carried out automatically. It supplies nerves to all the internal organs of the body and the blood vessels. These organs are self-controlled and not under the control of the will. The autonomic nervous system is divided into two parts.

(1) Sympathetic, and

(11) Para-sympathetic.

The majority of the organs of the body are supplied by both sympathetic and parasympathetic nerves which have opposite effects. One stimulates and the other checks the activity of the organs. For example, the sympathetic nerve stimulates the effects on the heart and respiration but checks the digestion, whereas parasympathetic nerves stimulate the digestive system, but slow down the heart and have a checking effect on respiration.Nervous System and Health

Health of the nervous system depends on the condition of the environm human nature, ways of living and social circumstances. Unhygienic habits like use tobbaco, alcohol and narcotic drugs also affect negatively on the thinking and worn efficiency of the brain and the parts of the nervous system. Under stress, too m worry, lack of proper sleep and rest, over mental work. absence of exercise, irreg habits may damage the cells of the nervous system. So, we need to be careful towa our daily routine, eating habit, physical exercise and social circumstances.

1.3 The Glandular System

There are many kinds of glands in the human body. These glands are made of special kinds of cells. All these glands and their functions comprise the glande system.

The glands found in the body are of two types. They are as follows:

1. Exocrine glands, and

2. Endocrine glands.

1.3.1 Exocrine Glands

Exocrine glands pour their secretions out through a duct, for example, salivary gland and liver. The secretions of exocrine glands are called enzymes. The enzymes secreted by exocrine glands produce chemical changes when they come in contact with other substances.

Pineal Gand

Thyroid Gle

Thymus

Parathyroid gla

1.3.2 Endocrine Glands

Endocrine glands are usually a group of cells and glands without ducts. They produce special substances called hormones, which are poured directly into the blood stream from the glandular cell. So, they are also known as ductless glands. The endocrine system consists of a number of distinct glands. The main endocrine glands are:

Pancrea

Adrenal gland

Ovanes

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(a) Pituitary glands,

(b) Pineal glands,

(d) Parathyroid glands,

(e) Thymus glands,

(f) Adrenal glands,

(g) Pancreas, and

(h) Gonads.

(a) Pituitary Glands: The pituitary gland is a small, oval-shaped body like a big pea. It is located in the base of the brain. It controls all the glands as the master. It has great influence on skeletal growth. It also affects the functions of ovaries and testes

(b) Pineal Gland: The pineal gland is a small body resembling a pine cone, which is situated under the brain.

(c) Thyroid Gland: The thyroid gland is located in the neck where the larynx joins the trachea. This gland helps to regulate the rate of metabolism. The thyroid gland secretes thyroid hormones called 'Thyroxin' and 'Tridothyroxin' An overactive thyroid gland will cause a bulging of the eyes and other symptoms. The thyroid gland requires a certain amount of iodine. When there is too little iodine in the water supply or in the food, a swelling called goiter may appear in the neck.

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(d) Parathyroid Glands: The parathyroid glands are small oval bodies, and are about the size of a pea. There are four parathyroid glands. The secretion of the parathyroid glands is called parathormone, which influences calcium and phosphorus metabolism, and controls the excretion of phosphate.

Over secretion of parathormone causes loss of calcium, which goes from the bones into the blood, and from there it is excreted in the urine. The bones become porous and brittle and the increased level of blood calcium may cause the formation of kidney stone.

Under-secretion of this hormone leads to a sharp decrease of calcium in the blood plasma. This condition is characterized by intense spasm of many of the muscles.

(e) Thymus: The thymus gland is located in the thoracic cavity behind the sternum. It is believed that it is related to the production of antibodies

(1) Adrenal Glands: The adrenal glands are paired

organs each of which is located at the top of each kidney. The hormones secreted from the adrenal glands regulate the level of glucose in the blood, and influence fat, carbohydrate and protein metabolism. Under-secretion of these hormones causes the disturbance in metabolism, loss of weight, muscular weakness, low-blood pressure, etc. whereas, over-secretion causes change in the genital system. In women, it may result in secondary male sex characters.

Adrenal glands

Right kidney

Leit kidney

Aorta

Right ureter

Inferior vena cava

Left ureter

Fig. 18. The positions of the adrenal glands and some of their associated

(g) Gonads: The sex glands, the testes in male and ovaries in female, are known un the common name of gonads. These glands internally secrete sex hormones which delivered into the circulatory system and influence the various functions.

The ovaries secrete estrogen and progesterone, which influence the sex maturation of the female organs, regulate the monthly period, prepare the uterus ovulation, and influence the normal course of pregnancy.

The testes secrete testosterone and androsterone hormones, which influence sexual development and excite the activity of the sex.

(h) The Pancreas: The pancreas lies across the posterior abdominal wall behind stomach. It is a mixed gland composed of lobules. Pancreas produces pancreatic jui which is delivered to the duodenum. It also secretes a hormone known as insulin. In ca of insulin deficiency, only a portion of carbohydrate is used by the body. The remain carbohydrate is secreted in the form of sugar in urine. Thus, the deficiency of insul results in diabetes.

Glands and Health

1.4.1

Glands of our body secrete various enzymes and hormones, which are essent for the proper growth, development and regulation of our body. Over secretion or und secreation of these glands may create physiological disturbances in the body which the sign of ill health. In fact, these glands only work efficiently in a healthy situation, an the healthy condition can be maintained only through the balanced diet, maintenance personal hygiene, healthy habits and proper exercise.

1.4 The Reproductive System

New life begins with the union of a male sex cell and a female sex cell. These sex cells are developed in the reproductive organs. In man, as in all higher animals, the function of reproduction IS connected with special apparatus of the reproductive system. The reproductive system is divided into two main parts. They are as follows:

Sperm duct-(vas deferens)

Front of pelvis-

Penis

Erectile tissue.

Urethra

Foreskin Testis

Fig 19 Section of the male reproductive organs

1. The Male Reproductive System, and

2. The Female Reproductive System.

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Our Health and Physical Education1.4.1 The Male Reproductive System

The male reproductive system is designed to produce numerous minute spermatozoa, to store them and into transfer them to the reproductive passage of the female. The male reproductive system consists of the following organs: (i)

Scrotum

(ii) Testes

(iii) Epididymis

(iv) Vas deferens

(v) Seminal Vesicles

(vi) Ejaculatory ducts

(vii) Prostate gland

(viii) Urethra, and

(ix) Penis.

(i) Scrotum: The scrotum is a pouch of smooth muscles and lies in front of the upper part of the thighs and behind the penis. The testes are placed in the scrotum.

(ii) Testes: The testes are smooth and oval paired organs. In each testis, there are about 200 to 300 lobules which are ultimately united in the epididymis. The testes produce the spermatozoa and secrete the hormone called testosterone. It is responsible for the maintenance of male characteristics during youth and middle age.

(iii) Epididymis: The epididymis is a small, coiled organ lying behind the testes. Through this tube, the sperms pass from testes into the vas deferens.

iv) The Vas Deferens: The vas deferens is a tube which leads from the epididymis and s joined by the seminal vesicles and together they form the ejaculatory duct.

v) The Seminal Vesicles: The seminal vesicles are two pouches lying on the posterior spect of the bladder. The seminal vesicles are the reservoirs for the seminal fluid. They roduce sticky fluid which keeps the spermatozoa alive and in which sperms remain vimming.

i) Ejaculatory Duct: The ejaculatory ducts are two tubes, each formed by the union the duct from a seminal vesicle and a deferent duct, and open into the urethra. During ejaculation, semen and sperm pass through this tube.

i) Prostate Gland: It lies below the bladder, surrounding the urethra, and is composed glands, ducts and involuntary muscles.(viii) Urethra: The male urethra provides a common pathway for the flow of urine semen.

(ix) Penis: The urethra opens at the tip of the penis, and spermatozoa can be inje through it into the vagina of the female.

(iv) C

(V) V

(vi) 1

Production of Sperm

We have learned that, the male reproductive system includes the testes, ure (vii) C vas deferens, prostate gland, seminal vesicles and penis. In this process there is a sys of tiny tubes. These tubes, called the seminiferous tubules, house the germ cells. T) also produce testosterone which is the male sex hormone which helps in product of sperm. These seminiferous tubules, are the sites of sperm production. The spe production occurs in the testicle upon reaching puberty. A man produces millions sperm cells every day, each measuring about 0.002 inches (0.05 millimiter) long.

(viii) P

(b) In organs system consist

In male reproductive system, the epididymis lies on top of the seminifero tubules. The epididymis is a cordlike structure, where the immature sperm migrate fro the seminiferous tubules to the epididymis to mature and be stored. Thus, when a m is stimulated for sexual activity, the sperm are mixed with seminal fluid. As a result the stimulation, the semen, which contains up to 500 million sperm, is pushed out oft penis (ejaculation) through the unethra.

(i) Th

fro D flu in fro

1.4.2 The Female Reproductive System

The female reproductive system is designed to produce ova and to provide young with a suitable place to grow and with nourishment during the early part of life.

(a) External Organs: The external female reproductive organs are collectively known as the 'vulva' which consists of:

(i) Mons Pubis: It is a pad of fat covered with skin. It bears hair (pubic hair) after puberty.

(ii) Labia Majora: It is a two-fold skin which forms the boundary of the vulva.

(iii) Labia Minora: These are two smaller folds of skin situated

between the upper parts of the labia majora.

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(iv) Clitoris: It is a small sensitive organ. It lies in front of the vulva.

(v) Vestibule: The vestibule is the cleft between the labia minora.

(vi) Hymen: The hymen is a band of mucous membrane and is placed at the orifice of the vagina.

(vii) Greater Vestibular Glands: They are glands situated under each labia majora on either side of the vaginal opening.

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(viii) Perineum: The perineum is the expanse of skin from the vagina to the anal canal.

(b) Internal Organs: The internal organs of the female reproductive system lie in the pelvic cavity and consist of:

Uterus

Ligament of ovary

Uterine tube

Peritoneum

Fimbriated end of uterine tube

ات

(i) The Vagina: The vagina extends from the vestibule to the uterus. During copulation the seminal fluid is discharged from the penis into the vagina. The foetus passes from the uterus through the vagina.

Suspensory ligament of ovary

Cut edge of broad Igament

Round ligament

Fig. 1.11. The main ligaments supporting the uterus (only one side shown)

(ii) Uterus: The uterus is a hollow, muscular, pear-shaped organ. It lies in the pelvic cavity between the urinary bladder and the rectum. Cervix It provides the environment for the growing foetus, and if the ovum is not fertilised, the uterus helps in the menstruation cycle.

Vagina

(iii) Fallopian Tubes (Uterine tubes): The fallopian or uterine tubes extend one on each side, from the upper angle of the uterus outward. They receive ova after ovulation and transmit the ova from the ovaries to the cavity of the uterus. They also provide the sites for ova fertilization.

(iv) Ovaries: The ovaries are small female glands placed one on each side of the uterus. They produce the ova and the hormones called oestrogen and progesterone

Menstruation

Menstruation is a function of the uterus that start at puberty as a result of ova activity and consists of the periodic discharges of blood from its cavity. This is a scried events, occurring regularly in a female every 26 to 30 days throughout the childbear period of about 36 years. Menstruation is observed from the age of 12-14 to 45-46. Repr purpose of menstruation is to prepare the mucous membrane of the uterus to receiv fertilised ovum. So long as the fertilised ovum does not arrive, it gives the endometri an opportunity to make a fresh preparation. Thus, menstruation is really a clearing un these changes in the endometrium.

The ovary discharges ovum in the fallopian tube once a month, which pass towards the uterus. If the sperm after copulation mixes with the ovum, there possibility of fertilisation. At this stage, the endometrium becomes thicker by rapid multiplication, accompanied by an increase in the numbers of mucus secreting glan and blood capillaries. Thus, the uterus receives, nourishes and protects a fertilised ov If there is no fertilisation or if the ovum is not able to fertilise with the male sperm, the it dies within a few days. If the ovum is not fertilised, menstruation occurs and a ne cycle begins.

The average length of the menstrual cycle is about 28 days. By convention, t days of the cycle are numbered from the beginning of menstruation which usually lar about 3 to 5 days followed by the various phases.

Ova Production

Ovary is one of a pair of female glands in which the eggs (ova) form and female hormones estrogen and progesterone are made. These hormones play an important role in female traits, such as breast development, body shape, and body hair. As the female matures, so do her ovaries. The ovaries lie on either side of the uterus.

The ovaries produce the egg cells, called the ova or oocytes. The oocytes are then transported to the fallopian tube where fertilization by a sperm may occur. Ovaries release anegg. or sometimes more, on each menstrual cycle. Inside each ovary, there are follicles and inside of each follicle is a dominant egg

of ove scne Idbee 5-46 recen met by the activity of the male and female

Reproduction

Reproduction is brought about essential sex-organs, the testes and ng ovaries, producing male and female sex pa cells, sperms and ova. The male sex cells resperms deposited in the vagina during Pid copulation- can survive about 24 hours. gl The sperms are very small and mobile How having a head and a very long tail, which enable them to make their way towards the female cell, the ovum.

Ovarian (20)

Meiosis

Egg

Fertilization

Spermatic (2n)

Melosis

Baby

Sperm

Mitosis

Oosperm (2n)

The ovum is a female sex cell which is produced by the ovary every an, month after menstruation. The ovum has a life of about 48 hours. It is received by the fallopian tube and passes towards the uterus. When a sperm meets an ovum and fuses with it, which normally takes place in the uterine tube, it is called the fertilization and a new cell is developed, that is the fertilised ovum. The fertilised ovum continues its journey down the tube towards the uterus which takes about a week. It then becomes embedded in the wall of the uterus, which gives rise to the formation of an entirely new complete human being.

Fertilization

Sperms

Ovum

is Fertilization the process of fusion of ovum and sperm, to form the diploid zygote. Fertilization is more a chain of events than a single isolated phenomenon. Fertilization happens when a sperm cell successfully meets an ovum. The result of this union, leads to the production of a zygote cell (fertilized egg), initiating prenatal development. Once fertilization takes place, newly fertilized cell (called zygote) will move down the fallopion tube and into the uterus.Conception is successful joining of egg and Day 1 sperm. This process can occur in hours to days after having sexual intercourse. During sex, a male ejaculates and releases semen Ovulated egg into the vagina. Within the semen lies the sperm which moves to a woman's cervical mucus. Some sperm makes it, but many will die before reaching the cervical mucus. Fom here, the strongest sperm will travel to th fallopian tubes and wait for an egg to fertilize. If the two meet up, conception can occu

In humans the conception process begins with ovulation, when an ovum (egg which has been stored in one of the mother's two ovaries, matures and is released in the fallopion tube. Ovulation occurs about halfway through the woman's menstru cycle and is aided by the release of a complex combiination of hormones.

Reproduction and Health

Reproduction is a natural process. In the same way sexual desire is a physical need. But it does not mean that, the individual may give birth to a baby at any time or they may involve in sexual activities before maturation. Generally, the organs of the body are developed fully at the age of later adolosence, meaning at the age of 18 to 21 years. So, the girls should be married only after the age of 18 years. and she should be a mother only after the age of 20 years. Moreover, bearing many children is also injurious to the health of the mother. So, the use of contraceptives to the control child birth and to maintain gap between the birth of two children should me encouraged. Besides this, the sexual relation should be safe, controlled and in isciplined and concensual way.

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