notes+period+7+unrinary

The excretory system contains several different organs. These organs are: the kidney, the skin, and the bladder. The nephrons, in the kidneys, are the ones that actually do the filtering of the blood

In anatomy, the **urinary bladder** is a hollow, muscular, and distensible (or elastic) organ that sits on the pelvic floor in mammals. It is the organ that collects urine excreted by the kidneys prior to disposal by urination. Urine enters the bladder via the ureters and exits via the urethra.In males, the bladder is superior to the prostate, and separated from the rectum by the rectovesical excavation.In females, the bladder is separated from the uterus by the vesicouterine excavation.

he human kidneys:
 * are two bean-shaped organs, one on each side of the backbone.
 * Represent about 0.5% of the total weight of the body,
 * but receive 20–25% of the total arterial blood pumped by the heart.
 * Each contains from one to two million **nephrons**.

Many invertebrates such as flatworms use a n ephridium as their excretory organ. At the end of each blind tubule of the nephridium is a ciliated flame cell. As fluid passes down the tubule, solutes are reabsorbed and returned to the body fluids. On this page you will learn about the Excretory System, which removes the unwanted materials from our body. The word excretion means the removal of waste substances from the body. Several organs are involved with the excretory system, including the kidneys, sweat glands, lungs. and rectum, The primary organs of excretions, however, are the kidney. Excretion is vital to the health of the body because the wastes are poisonous. If the wastes build up and are not eliminated, they can cause serious problems. As you know, carbon dioxide and water vapor are removed by the lungs. Other wastes, namely urea, uric acid, various salts, and assorted nitrogenous wastes , are removed by the kidneys and sweat glands.

__KIDNEYS__
Most of you seem unsatisfied with the information here so I thought I'd add a little on the Kidneys. Feel free to e-mail me if you need anything specific, I just may be able to help you and I check my e-mail around 4 or 5 times a day THE KIDNEYS The kidneys provide an important filtering system for the blood. They remove the waste products of chemical reactions in the body, as well as substances that are in excess amounts, for example water. If chemical wastes are not removed, they would slowly poison you by killing all the cells in your body. Urea, made in the liver from unwanted amino acids, is one chemical excreted by the kidneys. There are two kidneys, one on either side of the body. Each kidney has a rich blood supply. Approximately one litre of blood flows through the kidneys per minute. The kidneys remove waste products from the blood using small filters called nephrons. The waste products, now called urine, drain into a tube called the ureter that connects to the bladder. The bladder stores the urine and when it is full a muscular ring opens up, allowing the urine to go through the outlet tube called the urethra.

**Anatomy (What does it look like?)**
 * __Bladder__ **

The urinary bladder is a muscular bag which has a more or less spherical "balloon" shape and is located at the end of both ureters, low down in the abdomen, behind the pubic bone. The bladder normally contains about 400 cc.(12oz) of urine. Both ureters diagonally pass through the bladder wall being squeezed when the bladder fills prohibiting reflux of urine from the bladder to the kidneys. The openings of the ureters are located near the bladder outlet. A triangle is thus formed between the two ureteral openings and the bladder outlet, which is the beginning of the urethra. In the male, the rectum (lower bowel) is right behind the bladder and the prostate is located right under the bladder, around the urethra. In the female the uterus and vagina lie in between the bladder and the rectum. The female urethra is relatively short - only an inch or so, opening between the labial lips. Bladder awareness and emptying are regulated by nerves which are connected to the brain through the lower spine. **Function (What does it do?)**

The urinary bladder is a rather simple organ. The urine, produced by the kidneys, is transported by the ureters towards the bladder to be stored there. A second important feature of the bladder is the voiding of stored urine once a suitable place and time has been found. In order to get this done as quickly as possible, the bladder wall is equipped with muscle fibers which contract to pull open the bladder neck and expel urine into the urethra. At the same moment the sphincter muscle around the urethra, that normally closes the outlet to prevent leaking, relaxes and urine flows out of the urethral opening. Fortunately, we do not have to think about those things while passing urine; everything is controlled by nerve cells in the brain, the spine and around the&nbspbladder. Stretching of the bladder wall gives the brain a signal that the bladder is going to need emptying. Normally, the brain is able to suppress the bladder contraction until it is convenient to void

**lungs**
> go into the lungs.  Liver is the largest gland in the human body one of the most complex organ in the human body it is one of the major storehouse for food it is reddish-brown and mass weighing is 1.5 kilograms it lays in the upper right abdomen under the daiphragm and above the stomach
 * It is also a part of the   respiratory system
 * the bronchi, air passes into each lung.
 * The air then follows narrower and narrower bronchioles until it reaches the alveoli.
 * then it goes down the trachea through your vocal cords in the larynx until it reaches the bronchi.
 * the lungs takes in the air and transfer it into the cell through the blood streams and this shows cellular respiration
 * then carbon dioxide comes back up throw the blood stream and into the lungs and into the air.
 * lungs are made of spongy, elastic tissue that stretches when you breath
 * The airways that bring air into the lungs are made of smooth muscle and cartilage
 * the diaphragm and intercostal muscles ( inside your rib cage) expand the chest cavity
 * you exhale the diaphragm and intercostal muscles relax and the chest cavity gets smaller
 * As you breathe air in through your nose or mouth, it goes past the epiglottis and into the trachea.
 * breathing is a form of diffuses
 * your lungs are 90% air and 10% tissue
 * The right lung has three lobes and the left lung has two
 * Your nose and mouth filters the air and gives it heat and moisture before it gets to the lungs.
 * The air moves through a tube called the windpipe or trachea. The trachea divides into the right and left bronchus that are large airways that
 * It is dome shaped and lies below the lungs separating them from the abdomen. Two thin layers of tissue called the pleura cover each lung and the inside of the rib cage. These layers or membranes, slide back and forth over each other as we breathe.
 * The inside of your lungs looks like a giant sponge. It is a mass of fine tubes, the smallest of which end in tiny air sacs called alveoli. These air sacs have very thin walls which are criss-crossed with hundreds of tiny blood vessels called capillaries. There are 200 million or so of these air sacs, and if they were to spread out they would cover a piece of ground roughly the size of a tennis court.
 * Each lung is between 10 and 12 inches long
 * liver**
 * liver**