Inside Yourself

Looking Inside Your Body

Just What is Inside You?

Have you ever wondered just what is in your body? Have you ever wondered what your made up of? Have you ever wondered how you are what you are? This will answer all of those questions you've ever asked.

Homeostasis and Cells

Let's begin with homeostasis - the ability of the body to maintain a stable internal environment in response to change. Whenever you jump into cold water, or have been out in the cold without much warmth, you'll notice how some parts of your body, like your fingers or toes, will become numb. This is because the warmth in your body is retreating slowly towards your core, trying to keep your innermost body warm. This is homeostasis. To maintain homeostasis, all the cells in your body must work together. Not every cell has to do every single job for your body though, each has a special job to help maintain homeostasis, and keep you warm. For example, nerve cells move electrical messages around the body, and white blood cells patrol the body and attack invading bacteria.

Tissues, Organs, and Organ Systems

When cells are grouped together to do a specific job, they become tissue. You and animals have four main types of tissue. They are epithelial tissue, connective tissue, muscle tissue and nervous tissue. A single tissue alone though, it cannot do as much work as two or three tissues working together. A group of 2 or more tissues becomes an organ. Have you ever wondered how your heart gets all of the blood around your body? This is a good example of an organ system. Your heart is connected to blood vessels such as veins and arteries. These are organs working together. When organs work together, they form an organ system. Together, your heart, blood, and blood vessels form your cardiovascular system. Your body has twelve organ systems, and they all must work together in order for them to maintain homeostasis. One of the most important functions of organ systems is to provide cells with oxygen and nutrients and to remove toxic waste products such as carbon dioxide. A number of organ systems, including the cardiovascular and respiratory systems, all work together to do this.

Feedback Regulation and Positive and Negative Feedback Loops

This all begins with hormones. Hormones are the messengers of the endocrine system, regulate the activity of body cells. The release of hormones into the blood is controlled by a stimulus, or signal. Feedback Regulation occurs when the response to a stimulus has an effect of some kind on the original stimulus. The type of response determines what the feedback is called. There can be both a positive or a negative feedback loop. A negative feedback loop is much more common than a positive feedback loop. A negative feedback loop is one in which the response to a stimulus decreases the effect of the original stimulus. A positive feedback loop is one in which the response to a stimulus increases the original stimulus.

Your Skin

Your skin is what covers the outside of our bodies. Your skin provides a barrier. It keeps organisms that could harm the body out. It stops water from leaving the body, and

stops water from getting into the body. Your skin controls body temperature, it does this by making sweat, a watery substance that cools the body when it evaporates. Your skin gathers information about your environment. Special nerve endings in your skin sense heat, pressure, cold and pain. It helps the body get rid of some types of waste, which are removed in sweat. It acts as a sun block. A chemical called melanin is made by certain skin cells when they are exposed to sunlight. Melanin blocks sun light from getting to deeper layers of skin cells, which are easily damaged by sunlight. Your skin has two main types of skin on it, Thin and hairy, which is the most common type on the body, and thick and hairless, which is found on parts of the body that experience a lot of contact with the environment, such as the palms of the hands or the soles of the feet. Your skin is precious because it protects us in so many ways, but it too can be easily harmed. Sunlight is good for your skin, but if exposed the sun for too long without sunblock, it can become burned. If children and teenagers get too much exposure to the sun, it can lead to skin cancer, later on in adulthood. Too much exposure to the sun is the leading cause of skin cancer.

Injuries and Hygiene

Your skin is precious, and needs to be taken care of. There are ways to make sure that your skin is clean and taken care of. Sweat, oil, dirt, dust, and dead skin cells can build up

on the skin surface. If not washed away, the mix of sweat, oil, dirt, and dead skin cells can encourage the excess growth of bacteria. These bacteria feed on these substances and cause a smell that is commonly known as body odor. Dirty skin is also more prone to infection. Bathing every day helps to remove dirt, sweat and extra skin cells, and helps to keep your skin clean and healthy.

You've probably noticed that your skin is easily able to heal itself. Even large cuts are able to be healed, because your skin puts new scales up in the place of the cut away or damaged cells, that were hurt. But if a cut becomes too large, the cells are unable to reproduce themselves. Stitching the edges of the injured skin together can help the skin to repair itself. When the damaged cells and tissues have been replaced, the stitches can be removed.

Your Skeleton

Your skeleton is made up of bones and joints. It is what makes us so solid, so that we aren't just a lump of skin and cells on the ground. Bones are the main organs of the skeletal system. They are made up of living tissue. Humans are vertebrates, which are animals that have a backbone. The sturdy set of bones and cartilage that is found inside vertebrates is called a skeleton. An adult has 206 bones. I bet you didn't know that children and babies have more bones and cartilage than an adult does! This is because the extra bones grow together into single bones because they aren't needed. Although your skeleton gives shape and form to your body, it is also an important factor in maintaining homeostasis. Support. The skeleton supports the body against the pull of gravity, meaning you don’t fall over when you stand up. The large bones of the lower limbs support the rest of the body when standing. Protection. The skeleton supports and protects the soft organs of the body. For example, the skull surrounds the brain to protect it from injury. The bones of the rib cage help protect the heart and lungs. Movement. Bones work together with muscles to move the body. Making blood cells. Blood cells are mostly made inside certain types of bones. Storage. Bones store calcium. They contain more calcium than any other organ. Calcium is released by the bones when blood levels of calcium drop too low. The mineral phosphorus is also stored in bones.

The Bones in Your Body

The skeleton is made up on mostly bones. Did you know that bones are organs? You'll remember that organs are made up of 2 or more tissues. Bones come in many different shapes and sizes, but they are all made up of the same thing. The two main types of bone tissue are compact bone and spongy bone. Compact bone makes up the dense outer layer of bones. Spongy bone is found at the center of the bone, and is lighter and less dense than compact bone. Bones look tough, shiny, and white because they are covered by a layer called the periosteum. Many bones also contain a soft connective tissue called bone marrow. There are two types of bone marrow - red marrow and yellow

marrow. Red marrow makes red blood cells, platelets, and most of the white blood cells for the body. Yellow marrow makes white blood cells. Bones come in four main shapes. They can be long, short, flat, or irregular. Bones are identified by their shape - never their size.

Your Joints and How to Keep Your Bones and Joints Healthy

A joint is where more than two bones meet together. There are three types of joints in the body. There are fixed joints do not allow any bone movement. Many of the joints in your skull are fixed. There are partly movable joints allow only a little movement. Your backbone has partly movable joints between the vertebrae. Then there are movable joints, which allow movement. There are four different movable joints. They are the ball and socket joint, the hinge joint, the gliding joints and the pivot joint. This brings me to my next point, how to keep your bones and joints healthy. You have to keep your bones strong - you don't want weak and brittle bones, which can easily break. Some ways to keep your bones strong, is by lifting weights, basketball, tennis, gymnastics, karate, running, and walking. Eating well is another important factor. How you eat when you are younger will affect your skeletal system for up to 50 years. You need to get a lot of calcium and vitamin D in your younger years, because if you don't, you will have bones that break more easily in your later life than it would have if you had eaten more calcium and vitamin D.

Injuries and How to Prevent Them

It is so easy to break a bone, you can do it while on the monkey bars, or falling from a ladder. This is called a fracture. They are usually caused by excess bending stress on the bone. Soon after the fracture, your bones begin to try and bend themselves. The area becomes swollen and sore. Within a few days bone cells travel to the break site and begin to rebuild the bone. It takes a few months before the compact and spongy bones form where the break was. Occasionally, bones need help to mend back together, and this is when the doctors have to help the bone mend by putting metal pieces in your bones in order to help them heal. Osteoarthritis occurs when the cartilage at the ends of the bones breaks down. The break down of the cartilage leads to pain and stiffness in the joint. Osteoarthritis is the most common form of arthritis. It has many causes, including aging, sport injuries, fractures, and obesity. A ligament is a short band of tough connective tissue that connects bones together to form a joint. There are also injuries here. Ligaments can get injured when a joint gets twisted or bends too far. Injuries to the ligaments are known as sprains. Ligament injuries can take a long time to heal. Treatment of the injury includes rest and special exercises that are developed by a physical therapist. Preventing these injuries is really quite simple. All you have to do is wear the right equipment for certain sports. For example, if you wear a helmet win you go biking, you can prevent a skull injury. If you warm up and cool down properly, you can prevent a muscle injury or a ligament injury. Stretching before and after activity also helps prevent injuries. Stretching can improve your posture, and helps prevent some aches and pains associated with tight muscles.