The Excretory System

1
The Excretory System

• Excretory system- a system that excretes waste
  from the body and regulate the chemical
  composition of body fluids by removing metabolic
  wastes and retaining the proper amounts of water,
  salts, and nutrients. Main organs of this system
  includes
• Skin
• Liver
• Lungs
• Kidneys

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Principal organs of the Urinary System

• Kidneys- pair of bean-shaped organs which are
  located in the middle of your back, just below
  your rib cage. They filter your blood and
  eliminate wastes produced by metabolism, and
  maintains the volume of water in your body.
• Bladder- is a hollow, muscular, balloon shaped
  organ that collects urine from your kidneys and
  stores the urine until its full enough to empty
  through the urethra.
• Continue..

3
Principal organs of the Urinary System

• Ureters- are muscular tubes that attach at their
  upper end to the kidneys and at their lower end
  to the bladder. Urine formed in the kidneys flows
  down into the bladder.
• Urethra- is a tube that drains urine from the
  bladder out of the body.
• Sphineter- a band of muscle that encircles an
  opening of the body or one of its hollow organs.
  (Bladder)
• Diagram answers
• 1.Kidneys
• 2.Ureter
• 3.Bladder
• 4.Urethra

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So how do your kidneys work?What do your
kidneys do?

• Your kidneys are vital organs that perform to
  keep your blood clean and chemically balanced.
  Your kidneys are located near the middle of your
  back, just below your rib cage. The kidneys are
  sophisticated machines. Every day, your kidneys
  process about 200 quarts of waste products and
  extra water. The yellowish colored waste and
  extra water excreted from your kidneys is called
  urine, which flows into your bladder and through
  tubes called ureters.
• The wastes in your blood comes from the food
  you eat, after the normal breakdown of active
  tissues. Your body used food for energy and
  self-repair. When your body has taken all the
  nutrients it needs it goes back into the blood
  stream. If your kidneys didnt remove the wastes
  then the wastes would build up in the blood and
  damage your body.

• The Renal Artery- is the artery that supplies
  the kidneys, some glands, and the ureters. So
  your blood couldnt get to your kidneys. Your
  kidneys dont filter your blood. Tiny nephrons
  are what filter your blood. In your kidney there
  is about a million nephrons. In each nephron
  holds a glomerulus which is a compact cluster of
  capillaries (blood vessels), and a small tube
  called a renal.
• The glomerulus intertwines with a tiny
  urine-collecting tube call a tubule. Then a
  complicated chemical exchange takes place, waste
  materials leave your blood and enter your urinary
  system. The tubules receive a combination of
  waste materials and chemicals that your body can
  still use. In addition your body creates three
  important hormones.

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Negative Feedback

• Your kidneys measure out sodium, phosphorus
  and potassium, and release them back into your
  blood and return to the body. This is your
  kidneys way of regulating the bodys level of
  those substances and having the right balance.
  But if the levels are too much it can be harmful.
  Plus if your body doesnt maintain healthy it
  could cause Homeostasis. Homeostasis is there to
  maintain internal stability, state of balance in
  the body. This is can cause negative feedback.
  Negative feedback is when the starting point is
  at normal then goes beyond range and returns back
  to normal once again. In addition your body
  creates three important hormones.
• Erythropoietin- stimulates bone marrow to make
  red blood cells
• Calcitriol- uptake of calcium
• Renin- regulates blood pressure

• .

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What does your Urinary System have to do with the
Excretory system?

• Urinary System
• The urinary system is part of the excretory
  system because its another way that your body
  gets rid of toxins that your body doesnt need.
  The urinary system works with the skin,
  intestines, and lungs which all excrete waste and
  help with keeping your body well balanced. Lungs
  take in oxygen to provide your blood with oxygen
  and breathe out toxins, like carbon dioxide. The
  urinary system removes a type of waste called
  urea. Urea is a compound found in urine, its
  produced when your food is broken down. Urea is
  carried in the bloodstream to the kidneys. Then
  urea goes through the excretory system and out of
  your body.

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SWEAT?

• Sweat is to excrete toxins or unneeded
  substances through the pores of the skin to
  perspire. Perspiration, or sweat, is your bodys
  way of cooling itself as well and excreting extra
  toxin or heat. Sweat glands are distributed all
  over your entire body. Sweat glands are a long,
  coiled, hollow tube of cells. Sweat glands are
  found in the layer of skin called the dermis
  along with other equipment such as never endings,
  hair follicles. The coiled part in the dermis is
  where sweat is produced, and the long portion is
  a duct that connects the gland pore. Pores area
  minute opening in the skins outer surface for
  perspiration.

• Two Types of sweat glands
• Eccrine- Active from birth Found
• in soles of feet and forehead, also in
• palms of hands.
• Apocrine- Active only at puberty
• Found in armpits and in hair follicles
• rather than pores.

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How Sweat is Made

• Sweat is made by several million sweat glands
  that are scattered around your skin. Each gland
  looks like a coiled-up tube with an opening on
  the surface of the skin. The job of a sweat gland
  is to make sweat, which evaporates from the skin
  to cool your body.
• Ingredients of
• Sweat
• Na-Sodium
• CI-Chloride
• K-Potassium
• H2O-Water

• Making sweat is partly controlled from
• your nervous system by an automatic
• reflex to cool your body. When the sweat
• glands are stimulated, the cells secrete a
• fluid that is similar to plasma. But unlike
• plasma sweat doesnt have proteins and
• fatty acids, just sodium, chloride, and
• potassium. The source where the fluid
• comes from is the spaced between the
• cells, which get the fluid from the
• capillaries in the dermis. Then the fluid travels
• from the coiled portion up through the straight
• duct. Then what happens next depends on how
• low or how high your sweat production is.
• Low- rest, cool temp.
• High- exercise, hot temp.
• FACT
• An adult male sweats enough in one day to fill a
  six-pack of soda cans!

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Why do we sweat?

• When your body gets hotter than 98.6 degrees,
  your brain doesn't like it, it wants your body to
  stay cool and comfortable. So the part of your
  brain that controls temperature, called the
  hypothalamus sends a message to your body,
  telling it to sweat. Then special glands in your
  skin called sweat glands start making sweat.
• Sweat is also known as perspiration, and it is
  made almost completely of water, with tiny
  amounts of other chemicals like ammonia, urea,
  salts, and sugar. Ammonia and urea are left over
  when your body breaks down protein. The sweat
  leaves your skin through tiny holes called
  pores. When the sweat hits the air, the air makes
  it evaporate. As the sweat evaporates off your
  skin, you cool down.
• Sweating plays an important role in the body
  because it helps maintain body temperature by
  cooling us down. When we're hot and we sweat,
  that moisture evaporates and cools us off a bit.
  We don't just sweat when we are hot. It's also
  normal for people to sweat when they're nervous
  because emotions can affect the sweat glands.