10th Class

         Sexually Transmitted Disease (STD)   A sexually transmitted disease (STD), also known as a sexually transmitted infection (STI), or venereal disease (VD), is an illness that has a significant probability of transmission between humans by means of human sexual behavior, including vaginal intercourse, oral sex, and anal sex. While in the past, these illnesses have mostly been referred to as STDs or VD, in recent years the term sexually transmitted infections (STIs) has been preferred, as it has a broader range of meaning; a person may be infected, and may potentially infect others, without showing signs of disease. Some STIs can also be transmitted via the use of IV drug needles after its use by an infected person, as well as through childbirth or breast-feeding. Sexually transmitted infections are as follows:           more...

       Reproductive Health   Birth control is a term for several techniques and methods used to prevent fertilization or to interrupt pregnancy at various stages. Birth control techniques and methods include contraception , contragestion and abortion. Contraception includes barrier methods, such as condoms or diaphragm, hormonal contraception, also known as oral contraception, and injectable contraceptives. Contragestives, also known as post-coital birth control, include intrauterine devices and what is known as the morning after pill.   The most common methods of hormonal contraception include the combined oral contraceptive pill and the minipill. Hormonal emergency contraception can be both contraceptive and contragestive.              Sterilization Surgical sterilization is available in the form of tubal ligation for women and vasectomy for men. Although sterilization is considered a permanent procedure due to the uncertainty of reversal possibility, it more...

           Sexual Reproduction   In this mode of reproduction both male and female are involved. The female egg cell fuse with the male egg cell to form zygote, which then develops into the new individual. These egg cells are also called gametes. When the male and female gametes fuses with each other, it forms zygote, which starts growing into new individual.               Flowering Plants Flowering plants are the dominant plant form on land and they reproduce by sexual and asexual means. Often their most distinguishing feature is their reproductive organs/ commonly called flowers. The anther produces male gametophytes, the sperm is produced in pollen grains, which is attached to the stigma on top of a carpel, in which the female gametophytes are located. After the pollen tube grows through the carpel's more...

       Introduction   We know that every living organism have a certain life span and it dies after sometime. So new organisms have to be produced in place of the dead organisms. Thus, the production of new organisms from preexisting organisms of the same species is known as reproduction. The reproduction ensures the continuity of life on earth. It gives rise to more organisms with same basic characteristics as their parents. Organisms look similar, because their body designs are similar. If the designs are to be similar, the blue prints for these designs should be similar. Thus, the reproduction at its most basic level will involve making copies of the blueprints of body designs. The DNA in the cell nucleus is the information source for making proteins. If the information is changed, different proteins will be made which eventually lead to altered body more...

       Coordination in Animals   The coordination in animals is brought by hormones and nervous system. The hormones are the chemical substance which controls the various growth activities in the animals and plants. The hormones are secreted by the endocrine system in the animals. The endocrine system consists of ductless glands which generates the hormones. The various endocrine glands in human being are as follows:               Pituitary Gland This gland is attached to the central part of the brain and secrets the pituitary hormones also called growth hormones. It controls the functioning of other endocrine glands. It also regulates the growth and development of body. If excess of hormones is stored then it cause gigantism and if insufficient of hormones is secreted, it cause dwarfism.   more...

         Coordination in Plants   Unlike animals, plants do not have nervous system for coordination and control of body activities. They does not have muscles for these activities. But despite all this, the plants responds to the stimulus and coordinates their function. There are infact specialized tissue in the plants for these activities. These specialized tissue is called xylem and phloem. Apart from these, the other substances, which helps in coordination are hormones. The different hormones found in plants are Auxin, gibberellins, cytokinins and abscisic acid. Auxins are founded in the apical meristem of the root tips and shoot tips. When the light falls on the shoot tips the auxin hormones get excited and speeds up the cell division at the shoot tips and leads to the elongation of shoots of the plants. The second hormone, gibberellins helps in elongation of stem more...

         Human Brain   One of the most important part of the human body is the human brain. All the thinking and memory work is done by the brain. It is divided into three parts fore brain, mid brain and hind brain. The fore brain is the main thinking part of the brain. It receives sensory impulses from various receptors. Different areas of fore brain are specialized for hearing, smell, sight and so on. Many of the involuntary actions such as watering of mouth when we see some delicious food, heart beat etc are controlled by the mid brain and hind brain. The other involuntary actions such as blood pressure, salivation, vomiting etc are controlled by the medulla of the hind brain. The activities such as walking in straight line, riding a bicycle, picking up pens etc are controlled by cerebellum of more...

         Tropic Movement   The movement of organism towards or away from the stimulus is called tropic movement. If the movement is towards the stimulus then it is called positive stimulus and if it is away from the stimulus then it is called negative stimulus. The various types of tropic movements are:                 Phototropism The response of organism towards the light is called phototropism. For example, a money plant kept in a pot in a room grows more towards the direction from which the light is coming, as compared to the other direction.                    Geotropism Response of organism towards the gravity is called geotropism. The root of the plant grows deep into more...

       Reflex Action   A reflex action, also known as a reflex, is an involuntary and nearly instantaneous movement in response to a stimulus. A true reflex is a behavior, which is mediated via the reflex arc. In animals, reaction time to visual stimuli is typically 150 to 300 milliseconds A reflex arc is a neural pathway that controls an action reflex. In higher animals, most sensory neurons do not pass directly into the brain, but synapse in the spinal cord. This characteristic allows reflex actions to occur relatively quickly by activating spinal motor neurons, without the delay of routing signals through the brain. Although the brain receives sensory input while the reflex action occurs.   There are two types of reflex arc - autonomic reflex arc affecting inner organs and somatic reflex arc affecting more...

         Introduction   In the previous chapter we have studied about the various activities involved in the maintenance of life process. In this chapter, we will discuss "how our body controls these various activities"?. How do we coordinate and response to the external stimulus? There must be a system which provides the control and coordination activities in the multicellular organisms. The ability of the organism to detect changes and make appropriate response is called sensitivity. Anything to which an organism responds and reacts is called a stimulus. Animals response to the stimulus either by moving towards it, or by moving away from it. Response and coordination in animals involve the sense organs, nervous system and hormones.            Nervous System The nervous system is an organ system containing a network of specialized cells, called more...