What is our body made up of?
Just as thousands of bricks are used to build a house.Our body is made of millions of tiny cells.Our whole body is supported by a bony structure called the Skeleton.
All living things are made up of cells-plants as well as animals.while most creatures are made up of many cells.there are few single celled creatures like the tiny microscopic amoeba.there are many types of cells.
- Tissues:similar types of cell join together to form a tissue.just like the bricks are joined together to form a wall,cell of similar type join to form a tissue.Tissues are also of many types.The tissues that make up the muscles are different from the tissues that make up the bones.
- Organs:Different types of tissues join to form an organ.If you are asked,”which sense organ helps you to smell?you”ll immediately say”Nose” but if you will be asked “which organ helps in digesting your food? i think you’ll get a bit puzzled.No single organ can carry out the process of Digestion. The task is so big that one single organ can not carry it out alone.its a Group of organs carry out this function all together.the organs cooperate with each other in a perfect manner to carry out this important process.This is a perfect example of “Team Work” When a group of organs cooperate to carry out a function of the body,we call it an organ system. chart chart lets now look at a few organ system in our body and how these function.
- Blood:As well as organs,a human body contains upto five litres of blood.your heart pumps blood around your bodyalong thousands of tubes calles “blood vessels”.As it flows along,blood delivers oxygen and food to every part of your body.
- Skin:Your skin gives your whole body a waterproof covering and protects your insides from dirt and germs.skin is made up of two main layers.The top layer of skin is called the epidermis and underneath the epidermis is a thicker layer called the dermis which is hair shaft.
- Bones and Muscles:Bones and muscles are your bodys support system.
Your skeleton-All the bones in your body together make up
your skeleton,which acts as a framework for your whole body.Bendy joints where bones meet let you move into different positions.
Muscles-The bones of your skeleton are moved by muscles.These help you move in all kinds of ways.Muscles work by contracting.As a muscle contracts,it pulls on the bones its joined to,and they move.
The Digestive System:
you know that all living things need food and water.what happens to the food we eat and the water we drink? Our body can not use the food we eat as it is. it has to be broken down into simple substance which are soluble in water.This process of changing the food into simpler substances is called digestion
- Mouth : the process of digestion starts in the mouth.We chew the food with our teeth.As we chew the food a juice is secreted in the mouth.This juice is called saliva.saliva mixes with the food and makes it soft.The more you chewyour food,the better is the mixing with saliva.the starch in the food is then changed to sugar.After the food is chewed properly,you swallow it.It goes down a tube called the food pipe.The food pipe carries the food to the stomach.
- Stomach:the stomach is like a muscular bag.The walls of the stomach secrete another juice .This juice helps to change the chewed food into simpler substances.From the stomach the food goes into the small intenstine.
- Small intenstine-It is a long coiled tube.Some more juices mix with the food here.Then walls of the small intenstine absord the digested food and pass it on to the blood vessels.The blood vessels carry the digested food all over the body,supplying it with nutrition.some parts of the food are not digested.This undigested food reaches the large intenstine.
- Large intenstine: The wall of the large intenstine absorbs the water and the rest of the undigested food is thrown out of the body through the anus.
Points to remember:
The wet food should leave the body,otherwise it will harm your health.That is why you should develop regular toilet habits.
Fill in the blanks with correct alternatives:
1. The process of digestion begins in the ______________.(stomach/mouth) 2. Similar types of cells join together to form______________.(an organ/ a tissue)
3. The walls of the small intestine absorb the _________________.(water/digested food)
4. waste food is stored in the _______________(large intenstine/small intestine)
5. Saliva is secreted in the ____________(stomach/mouth)
The Circulatory System:
The circulatory system consists of the Heart and Blood Vessels.
put your hand on the left side of your chest.what do you feel ?This beating is from your heart.Your heart is the size of your fist.the heart is like a pump.It pumps the blood to all parts of your body.It works 24 hours.
There are three types of blood vessels that carry blood around your body.
The Arteries and the veins are large blood vessels and capillaries are thin hair like blood vessels. Arteries generally carry pure blood from the heart and the veins usually carry impure blood back to the heart.You must have seen doctors use an instruments called “stethoscope”.They use this instrument to listen to your heart beat.
- What is pulse?
Pulse is the “heart beat”.Place three fingers on your wrist just below the thumb.You’ll feel your pulse.
- What is the function of the blood?
Blood carries digested food and oxygen to all parts of your body,to each and every cell.It also brings back the waste(impure blood)produced in the cells,back to the heart. The heart sends this impure blood to the lungs to be purified.this goes on without any break.even when you are sleeping,The heart and the lungs keep on working to keep your body fit.
The Respiratory System:
All living things breathe.We breathe in through our nose.
Nose:It has fine hair,which trap dust particles and very tiny insects.So always breathe through your nose and not through your mouth.
The respiratory system consists of the nose,winepipe and a pair of lungs.As you breathe in through your nose,air(containing oxgyen)goes in.Through the windpipe it reaches the lungs.
The lungs are made up of thousands of air-sacs,which look like bunches of grapes.Each air-sac is surrounded by capillaries.These capillaries contain impure blood brought from the heart.As the air containing oxygen reaches the air -sacs,the capillaries release carbon dioxide and absorb the oxygen.There is an exchange of gases in the lungs.The air-sacs now contain carbon dioxide.This carbon dioxide leaves your body,as you breathe out.This process goes on continuously.
The Excretory System:
The excretory system plays a crucial role in maintaining the body’s internal balance by removing waste products generated from metabolic processes. This system is essential for overall health, as it helps to regulate fluid balance, electrolytes, and the body’s pH levels. Here’s a closer look at how the excretory system functions and its key components.
Key Functions of the Excretory System
Waste Removal: The primary function of the excretory system is to eliminate waste products from the body. These wastes can include:
- Urine: Produced by the kidneys, urine contains urea, creatinine, and various ions that are filtered from the blood.
- Excreta: Solid waste expelled from the digestive system, primarily consisting of undigested food and bacteria.
- Sweat: Released through sweat glands, sweat helps regulate body temperature and also contains small amounts of waste products.
Regulation of Body Fluids: The excretory system helps maintain the balance of fluids in the body. By adjusting the volume and concentration of urine, the kidneys can conserve or excrete water as needed.
Electrolyte Balance: The kidneys play a vital role in regulating electrolytes such as sodium, potassium, and calcium, which are essential for various bodily functions, including nerve transmission and muscle contraction.
pH Regulation: The excretory system helps maintain the acid-base balance in the body by excreting hydrogen ions and reabsorbing bicarbonate from urine.
Major Components of the Excretory System
Kidneys: The primary organs of the excretory system, the kidneys filter blood to produce urine. They contain nephrons, the functional units that perform the filtration process.
Ureters: These are tubes that transport urine from the kidneys to the bladder.
Bladder: A muscular sac that stores urine until it is ready to be excreted from the body.
Urethra: The tube through which urine is expelled from the bladder to the outside of the body.
Conclusion
The excretory system is vital for maintaining homeostasis in the body by efficiently removing waste products and regulating essential bodily functions. Understanding how this system works can help us appreciate the importance of hydration, nutrition, and overall health in supporting our excretory functions. Regular check-ups and a healthy lifestyle can contribute to the optimal functioning of this essential system.
The Nervous System: The Body’s Control Center
The nervous system is a complex network that plays a pivotal role in controlling and coordinating all other systems within the body. It is responsible for processing sensory information, regulating bodily functions, and enabling communication between different parts of the body. Here’s an overview of the nervous system, its components, and its functions.
Key Functions of the Nervous System
Control and Coordination: The nervous system integrates and coordinates the activities of various body systems, ensuring they work together harmoniously. It allows for quick responses to internal and external stimuli, maintaining homeostasis.
Sensory Processing: The nervous system receives and interprets sensory information from the environment through sensory organs. This includes sight, sound, touch, taste, and smell, allowing us to perceive and interact with the world around us.
Motor Function: It controls voluntary and involuntary movements by sending signals to muscles. This includes everything from walking and talking to reflex actions like pulling your hand away from a hot surface.
Cognitive Functions: The nervous system is responsible for higher cognitive functions such as thinking, memory, learning, and decision-making. The brain, as the central organ of the nervous system, plays a crucial role in these processes.
Emotional Regulation: The nervous system is involved in regulating emotions and behaviors. It influences our responses to stress, fear, and pleasure, contributing to our overall mental health.
Major Components of the Nervous System
Central Nervous System (CNS): Comprising the brain and spinal cord, the CNS is the control center of the body. It processes information and coordinates responses.
Brain: The brain is the command center, responsible for processing sensory information, controlling motor functions, and facilitating cognitive abilities.
Spinal Cord: The spinal cord acts as a communication highway between the brain and the rest of the body, transmitting signals to and from the brain.
Peripheral Nervous System (PNS): The PNS connects the CNS to the limbs and organs. It is divided into two main parts:
Somatic Nervous System: This system controls voluntary movements and transmits sensory information to the CNS.
Autonomic Nervous System: This system regulates involuntary functions such as heart rate, digestion, and respiratory rate. It is further divided into the sympathetic (fight or flight response) and parasympathetic (rest and digest) systems.
Conclusion
The nervous system is essential for the proper functioning of the body, acting as the control center that coordinates all activities. Its ability to process information and respond to stimuli is vital for survival and interaction with the environment. Understanding the nervous system’s structure and functions can help us appreciate its complexity and the importance of maintaining neurological health through lifestyle choices, such as proper nutrition, exercise, and mental well-being.
The Reproductive System: The Key to Life
The reproductive system is a vital biological system responsible for the creation of new life. It enables the reproduction of offspring, ensuring the continuation of species. This system encompasses a series of organs and processes that work together to facilitate reproduction. Here’s an overview of the reproductive system, its functions, and its components.
Key Functions of the Reproductive System
Reproduction: The primary function of the reproductive system is to produce offspring. This involves the formation of gametes (sperm in males and eggs in females) and the process of fertilization.
Hormone Production: The reproductive system is responsible for producing sex hormones, such as testosterone in males and estrogen and progesterone in females. These hormones regulate sexual development, reproductive cycles, and secondary sexual characteristics.
Nurturing Offspring: In females, the reproductive system provides the necessary environment for the development of a fetus during pregnancy. The uterus, in particular, plays a crucial role in nurturing the developing baby until birth.
Sexual Function: The reproductive system is involved in sexual intercourse, which is essential for the transfer of sperm to the female reproductive tract, facilitating fertilization.
Major Components of the Reproductive System
Male Reproductive System:
- Testes: The organs that produce sperm and testosterone.
- Epididymis: A coiled tube where sperm mature and are stored.
- Vas Deferens: The duct that transports sperm from the epididymis to the urethra.
- Seminal Vesicles and Prostate Gland: These glands produce seminal fluid, which nourishes and helps transport sperm.
- Penis: The external organ that delivers sperm to the female reproductive system.
Female Reproductive System:
- Ovaries: The organs that produce eggs (ova) and hormones such as estrogen and progesterone.
- Fallopian Tubes: The tubes through which eggs travel from the ovaries to the uterus; fertilization typically occurs here.
- Uterus: The hollow organ where a fertilized egg implants and develops into a fetus during pregnancy.
- Vagina: The canal that connects the external genitals to the uterus and serves as the birth canal during delivery.
Conclusion
The reproductive system is essential for the continuation of life, enabling the creation of new individuals and the nurturing of future generations. Understanding its structure and functions highlights the importance of reproductive health and education. Maintaining a healthy reproductive system through regular check-ups, safe practices, and informed choices is crucial for overall well-being and the ability to reproduce successfully.