Human Body systems

The Heart

The Heart is an amazing organ. The heart beats about 3 BILLION times during an average lifetime. It is a muscle about the size of your fist. The heart is located in the center of your chest slightly to the left. It's job is to pump your blood and keep the blood moving throughout your body.
It is your job to keep your heart healthy and there are three main things you need to remember in order to keep your heart healthy.
Exercise on a regular basis. Get outside and play. Keep that body moving (walk, jog, run, bike, skate, jump, swim).
Eat Healthy. Remember the Food Pyramid and make sure your eating your food from the bottom to top.

The Blood

Blood Cells

Red Blood Cells
Red Blood Cells are responsible for carrying oxygen and carbon dioxide. Red Blood Cells pick up oxygen in the lungs and transport it to all the body cells. After delivering the oxygen to the cells it gathers up the carbon dioxide(a waste gas produced as our cells are working) and transports carbon dioxide back to the lungs where it is removed from the body when we exhale(breath out). There are about 5,000,000 Red Blood Cells in ONE drop of blood.
White Blood Cells (Germinators)
White Blood Cells help the body fight off germs. White Blood Cells attack and destroy germs when they enter the body. When you have an infection your body will produce more White Blood Cells to help fight an infection. Sometimes our White Blood Cells need a little help and the Doctor will prescribe an antibiotic to help our White Blood Cells fight a large scale infection.
Platelets
Platelets are blood cells that help stop bleeding. When we cut ourselves we have broken a blood vessel and the blood leaks out. In order to plug up the holes where the blood is leaking from the platelets start to stick to the opening of the damaged blood vessels. As the platelets stick to the opening of the damaged vessel they attract more platelets, fibers and other blood cells to help form a plug to seal the broken blood vessel. When the platelet plug is completely formed the wound stops bleeding. We call our platelet plugs scabs.

What is the Muscular System?

The Muscular System is a tissue or organ of the human body. It characterized by the ability to contract. Muscles are attached to internal organs, bones or blood vessels. They are also responsible for movement. The muscle system is composed of specialized cells called fibers. The muscle is made of long, thin muscles held together by the connective tissue. Each fiber has a number of nuclei. This system responses to a stimulus from the nervous system. (Muscles make up about 35% of the human body weight and 85% of the heat produced is caused by muscle contractions.) Almost all the movements are due to contractions. The contraction of a muscle cell is set on motion by the release of calcium inside the cell. The response to electrical changes occurs at the cell’s surface. There are exceptions where movements aren’t caused by contractions. For example in the cilium or in the flagellum on sperm cells.

What is the Myofibril?

The myofibril is the main unit for all muscles. Fiber or muscle cells contain several myofibrils that arrange myofilament of two types, thick and thin. The thick myofilament contains many molecules of the protein myosin. While the thick filament contains two strands of the protein actin. Myofibrils are made thick and thin myofibrils that alternative rows. These alternative rows of filaments slide along each other during contractions. Mitochondria surround the myofibril. Mitochondrion generates energy when the muscle is contracting.

What is the Smooth Muscles?

Until now, there are only three types of muscles known. One of them is the smooth muscle. The smooth muscle is also known as the visceral or involuntary muscle. The smooth muscle is spindle shaped cells. It is found in organs that are made of tissues. Some of the places are the heart and intestines that contain layers of connective tissue. Each spindle shaped cell contains a nucleus. The cells have a faint longitudinal striation. The nervous system prevents stimuli for contractions of the smooth muscle. Smooth muscles cells help create the structure of the skin, internal organs and blood vessels.

What is the skeletal muscle tissue?

The skeletal tissue is also known as the striated tissue. It is composed of long fibers. These long fibers are surrounded by sarcolemma. The skeletal tissue shape is like a sausage. The skeletal tissue contains many nuclei and has cross striations. It is supplied with nerves from the central nerve system. Since it is under a conscious control, it is known as the voluntary muscle. The skeletal muscle is attached to some parts of the skeleton by the tendons. Contractions of the skeletal muscle serve to move various bones as well as cartilages of the skeleton. The skeletal muscle forms the underlying flesh of the vertebrates. Most of the muscular problem is caused by strain.

What are some of the muscles that the human body contains?

One of the muscles that the human body contains is the frontalis. If you wish to see the frontalis, it located at the first picture. The frontalis has no joints and intersects at the galeal aponeurosis. The function of the frontalis is that it wrinkles the forehead and fixes galeal aponeurosis.
Deltoid is also a muscle. The nerve for deltoid is the axillary nerve. It intersects at the middle of the lateral surface of the humerus. Deltoid abducts arm, lateral rotate, anterior fibers flex, etc. The nerve for triceps is radial nerve. Triceps extends the elbow and stabilizes the shoulder joint. Gluteus maximus contains the inferior gluteal nerve. The gluteus maximus intersects at the gluteal tuberosity of femur. It is in charge of maintaining the knee extended via iliotibial tract. The trapezius intersects at the upper fiber to the clavicle. The spinal accessory nerve is part of the trapezius. The trapezius elevates and retracts scapula. These are only a few of the muscles that our bodies contain. There are many others and they all involve on movements.

What is the cardiac muscle?

The cardiac muscle forms most of the vertebrae heart. It is a very different tissue. It is only found in the heart. It requires to be supplied with oxygen. Unlike the smooth muscle, the cardiac muscle isn’t under the voluntary control. It is filled with the nerves from the autonomic nervous system. The autonomic impulses don’t speed up or slow down. The autonomic impulse isn’t in charge of the rhythmic contraction characteristic of a living cardiac muscle. The mechanism of the cardiac muscle isn’t understood. Heart attacks occur when there is insufficient blood supplied to the cardiac muscle.

Digestive System

The digestive system is made up of the digestive tract—a series of hollow organs joined in a long, twisting tube from the mouth to the anus—and other organs that help the body break down and absorb food (see figure).
Organs that make up the digestive tract are the mouth, esophagus, stomach, small intestine, large intestine—also called the colon—rectum, and anus. Inside these hollow organs is a lining called the mucosa. In the mouth, stomach, and small intestine, the mucosa contains tiny glands that produce juices to help digest food. The digestive tract also contains a layer of smooth muscle that helps break down food and move it along the tract.
Two “solid” digestive organs, the liver and the pancreas, produce digestive juices that reach the intestine through small tubes called ducts. The gallbladder stores the liver’s digestive juices until they are needed in the intestine. Parts of the nervous and circulatory systems also play major roles in the digestive system.

Movement of food through the system

The large, hollow organs of the digestive tract contain a layer of muscle that enables their walls to move. The movement of organ walls can propel food and liquid through the system and also can mix the contents within each organ. Food moves from one organ to the next through muscle action called peristalsis. Peristalsis looks like an ocean wave traveling through the muscle. The muscle of the organ contracts to create a narrowing and then propels the narrowed portion slowly down the length of the organ. These waves of narrowing push the food and fluid in front of them through each hollow organ.
The first major muscle movement occurs when food or liquid is swallowed. Although you are able to start swallowing by choice, once the swallow begins, it becomes involuntary and proceeds under the control of the nerves.
Swallowed food is pushed into the esophagus, which connects the throat above with the stomach below. At the junction of the esophagus and stomach, there is a ringlike valve, called the pyloric valve, closing the passage between the two organs. As food approaches the closed valve, the surrounding muscles relax and allow the food to pass through to the stomach.
The stomach has three mechanical tasks. First, it stores the swallowed food and liquid. To do this, the muscle of the upper part of the stomach relaxes to accept large volumes of swallowed material. The second job is to mix up the food, liquid, and digestive juice produced by the stomach. The lower part of the stomach mixes these materials by its muscle action. The third task of the stomach is to empty its contents slowly into the small intestine.
Several factors affect emptying of the stomach, including the kind of food and the degree of muscle action of the emptying stomach and the small intestine. Carbohydrates, for example, spend the least amount of time in the stomach, while protein stays in the stomach longer, and fats the longest. As the food dissolves into the juices from the pancreas, liver, and intestine, the contents of the intestine are mixed and pushed forward to allow further digestion.
Finally, the digested nutrients are absorbed through the intestinal walls and transported throughout the body. The waste products of this process include undigested parts of the food, known as fiber, and older cells that have been shed from the mucosa. These materials are pushed into the colon, where they remain until the feces are expelled by a bowel movement.

Production of Digestive juices

The digestive glands that act first are in the mouth—the salivary glands. Saliva produced by these glands contains an enzyme that begins to digest the starch from food into smaller molecules. An enzyme is a substance that speeds up chemical reactions in the body.
The next set of digestive glands is in the stomach lining. They produce stomach acid and an enzyme that digests protein. A thick mucus layer coats the mucosa and helps keep the acidic digestive juice from dissolving the tissue of the stomach itself. In most people, the stomach mucosa is able to resist the juice, although food and other tissues of the body cannot.
After the stomach empties the food and juice mixture into the small intestine, the juices of two other digestive organs mix with the food. One of these organs, the pancreas, produces a juice that contains a wide array of enzymes to break down the carbohydrate, fat, and protein in food. Other enzymes that are active in the process come from glands in the wall of the intestine.
The second organ, the liver, produces yet another digestive juice—bile. Bile is stored between meals in the gallbladder. At mealtime, it is squeezed out of the gallbladder, through the bile ducts, and into the intestine to mix with the fat in food. The bile acids dissolve fat into the watery contents of the intestine, much like detergents that dissolve grease from a frying pan. After fat is dissolved, it is digested by enzymes from the pancreas and the lining of the intestine.

Absorpstion and Transport of Nutrients

Most digested molecules of food, as well as water and minerals, are absorbed through the small intestine. The mucosa of the small intestine contains many folds that are covered with tiny fingerlike projections called villi. In turn, the villi are covered with microscopic projections called microvilli. These structures create a vast surface area through which nutrients can be absorbed. Specialized cells allow absorbed materials to cross the mucosa into the blood, where they are carried off in the bloodstream to other parts of the body for storage or further chemical change. This part of the process varies with different types of nutrients.
Carbohydrates. The Dietary Guidelines for Americans 2005 recommend that 45 to 65 percent of total daily calories be from carbohydrates. Foods rich in carbohydrates include bread, potatoes, dried peas and beans, rice, pasta, fruits, and vegetables. Many of these foods contain both starch and fiber.
The digestible carbohydrates—starch and sugar—are broken into simpler molecules by enzymes in the saliva, in juice produced by the pancreas, and in the lining of the small intestine. Starch is digested in two steps. First, an enzyme in the saliva and pancreatic juice breaks the starch into molecules called maltose. Then an enzyme in the lining of the small intestine splits the maltose into glucose molecules that can be absorbed into the blood. Glucose is carried through the bloodstream to the liver, where it is stored or used to provide energy for the work of the body.
Sugars are digested in one step. An enzyme in the lining of the small intestine digests sucrose, also known as table sugar, into glucose and fructose, which are absorbed through the intestine into the blood. Milk contains another type of sugar, lactose, which is changed into absorbable molecules by another enzyme in the intestinal lining.
Fiber is undigestible and moves through the digestive tract without being broken down by enzymes. Many foods contain both soluble and insoluble fiber. Soluble fiber dissolves easily in water and takes on a soft, gel-like texture in the intestines. Insoluble fiber, on the other hand, passes essentially unchanged through the intestines.
Protein. Foods such as meat, eggs, and beans consist of giant molecules of protein that must be digested by enzymes before they can be used to build and repair body tissues. An enzyme in the juice of the stomach starts the digestion of swallowed protein. Then in the small intestine, several enzymes from the pancreatic juice and the lining of the intestine complete the breakdown of huge protein molecules into small molecules called amino acids. These small molecules can be absorbed through the small intestine into the blood and then be carried to all parts of the body to build the walls and other parts of cells.
Fats. Fat molecules are a rich source of energy for the body. The first step in digestion of a fat such as butter is to dissolve it into the watery content of the intestine. The bile acids produced by the liver dissolve fat into tiny droplets and allow pancreatic and intestinal enzymes to break the large fat molecules into smaller ones. Some of these small molecules are fatty acids and cholesterol. The bile acids combine with the fatty acids and cholesterol and help these molecules move into the cells of the mucosa. In these cells the small molecules are formed back into large ones, most of which pass into vessels called lymphatics near the intestine. These small vessels carry the reformed fat to the veins of the chest, and the blood carries the fat to storage depots in different parts of the body.
Vitamins. Another vital part of food that is absorbed through the small intestine are vitamins. The two types of vitamins are classified by the fluid in which they can be dissolved: water-soluble vitamins (all the B vitamins and vitamin C) and fat-soluble vitamins (vitamins A, D, E, and K). Fat-soluble vitamins are stored in the liver and fatty tissue of the body, whereas water-soluble vitamins are not easily stored and excess amounts are flushed out in the urine.
Water and salt. Most of the material absorbed through the small intestine is water in which salt is dissolved. The salt and water come from the food and liquid you swallow and the juices secreted by the many digestive glands.

How is Digestive Process controlled?

Hormone Regulators
The major hormones that control the functions of the digestive system are produced and released by cells in the mucosa of the stomach and small intestine. These hormones are released into the blood of the digestive tract, travel back to the heart and through the arteries, and return to the digestive system where they stimulate digestive juices and cause organ movement.
The main hormones that control digestion are gastrin, secretin, and cholecystokinin (CCK):
Gastrin causes the stomach to produce an acid for dissolving and digesting some foods. Gastrin is also necessary for normal cell growth in the lining of the stomach, small intestine, and colon.
Secretin causes the pancreas to send out a digestive juice that is rich in bicarbonate. The bicarbonate helps neutralize the acidic stomach contents as they enter the small intestine. Secretin also stimulates the stomach to produce pepsin, an enzyme that digests protein, and stimulates the liver to produce bile.
CCK causes the pancreas to produce the enzymes of pancreatic juice, and causes the gallbladder to empty. It also promotes normal cell growth of the pancreas.
Additional hormones in the digestive system regulate appetite:
Ghrelin is produced in the stomach and upper intestine in the absence of food in the digestive system and stimulates appetite.
Peptide YY is produced in the digestive tract in response to a meal in the system and inhibits appetite.
Both of these hormones work on the brain to help regulate the intake of food for energy. Researchers are studying other hormones that may play a part in inhibiting appetite, including glucagon-like peptide-1 (GPL-1), oxyntomodulin (OXM), and pancreatic polypeptide.
Nerve Regulators
Two types of nerves help control the action of the digestive system.
Extrinsic, or outside, nerves come to the digestive organs from the brain or the spinal cord. They release two chemicals, acetylcholine and adrenaline. Acetylcholine causes the muscle layer of the digestive organs to squeeze with more force and increase the “push” of food and juice through the digestive tract. It also causes the stomach and pancreas to produce more digestive juice. Adrenaline has the opposite effect. It relaxes the muscle of the stomach and intestine and decreases the flow of blood to these organs, slowing or stopping digestion.
The intrinsic, or inside, nerves make up a very dense network embedded in the walls of the esophagus, stomach, small intestine, and colon. The intrinsic nerves are triggered to act when the walls of the hollow organs are stretched by food. They release many different substances that speed up or delay the movement of food and the production of juices by the digestive organs.
Together, nerves, hormones, the blood, and the organs of the digestive system conduct the complex tasks of digesting and absorbing nutrients from the foods and liquids you consume each day.

Functions

Its 206 bones form a rigid framework to which the softer tissues and organs of the body are attached.
Vital organs are protected by the skeletal system. The brain is protected by the surrounding skull as the heart and lungs are encased by the sternum and rib cage.
Bodily movement is carried out by the interaction of the muscular and skeletal systems. For this reason, they are often grouped together as the musculo-skeletal system. Muscles are connected to bones by tendons. Bones are connected to each other by ligaments. Where bones meet one another is typically called a joint. Muscles which cause movement of a joint are connected to two different bones and contract to pull them together. An example would be the contraction of the biceps and a relaxation of the triceps. This produces a bend at the elbow. The contraction of the triceps and relaxation of the biceps produces the effect of straightening the arm.
Blood cells are produced by the marrow located in some bones. An average of 2.6 million red blood cells are produced each second by the bone marrow to replace those worn out and destroyed by the liver.
Bones serve as a storage area for minerals such as calcium and phosphorus. When an excess is present in the blood, buildup will occur within the bones. When the supply of these minerals within the blood is low, it will be withdrawn from the bones to replenish the supply.

Types of Bones

The bones of the body fall into four general categories: long bones, short bones, flat bones, and irregular bones. Long bones are longer than they are wide and work as levers. The bones of the upper and lower extremities (ex. humerus, tibia, femur, ulna, metacarpals, etc.) are of this type. Short bones are short, cube-shaped, and found in the wrists and ankles. Flat bones have broad surfaces for protection of organs and attachment of muscles (ex. ribs, cranial bones, bones of shoulder girdle). Irregular bones are all others that do not fall into the previous categories. They have varied shapes, sizes, and surfaces features and include the bones of the vertebrae and a few in the skull.

Divisions of the Skeleton

Bone Composition

Bones are composed of tissue that may take one of two forms. Compact, or dense bone, and spongy, or cancellous, bone. Most bones contain both types. Compact bone is dense, hard, and forms the protective exterior portion of all bones. Spongy bone is inside the compact bone and is very porous (full of tiny holes). Spongy bone occurs in most bones. The bone tissue is composed of several types of bone cells embedded in a web of inorganic salts (mostly calcium and phosphorus) to give the bone strength, and collagenous fibers and ground substance to give the bone flexibility.

Parts of the respiratory system

Lungs
The lungs are the main organs of the respiratory system. In the lungs oxygen is taken into the body and carbon dioxide is breathed out. The red blood cells are responsible for picking up the oxygen in the lungs and carrying the oxygen to all the body cells that need it. The red blood cells drop off the oxygen to the body cells, then pick up the carbon dioxide which is a waste gas product produced by our cells. The red blood cells transport the carbon dioxide back to the lungs and we breathe it out when we exhale.

Trachea
The trachea (TRAY-kee-uh} is sometimes called the windpipe. The trachea filters the air we breathe and branches into the bronchi.

Bronchi
The bronchi (BRAHN-ky) are two air tubes that branch off of the trachea and carry air directly into the lungs.

Diaphragm
Breathing starts with a dome-shaped muscle at the bottom of the lungs called the diaphragm (DY-uh-fram). When you breathe in, the diaphragm contracts. When it contracts it flattens out and pulls downward. This movement enlarges the space that the lungs are in. This larger space pulls air into the lungs. When you breathe out, the diaphragm expands reducing the amount of space for the lungs and forcing air out. The diaphragm is the main muscle used in breathing.

Human Body systems

Sunday, October 19, 2008

2008 FORMULA 1 SINOPEC CHINESE GRAND PRIX (QUALIFYING RESULT

What is the job of Circulatory System?

The Heart

The Blood

Blood Cells

Plasma

Where Are Blood Cells Made?

The Blood Vessels

Arteries

Veins

Capillaries

Amazing Facts

What is the Muscular System?

What is the Myofibril?

What is the Smooth Muscles?

What is the skeletal muscle tissue?

What are some of the muscles that the human body contains?

What is the cardiac muscle?

Blog Archive

About Me

Digestive System

Why is digestion important?

How is Food digested?

Movement of food through the system

Production of Digestive juices

Absorpstion and Transport of Nutrients

How is Digestive Process controlled?

The Skeletal System

Functions

Types of Bones

Divisions of the Skeleton

Bone Composition

What is the Respiratory System?

Parts of the respiratory system

Why Do I Yawn?

Why Do I Sneeze?

What causes Hiccups?