Download Respiratory System As you learned, the circulatory system was

Respiratory System
As you learned, the circulatory system was responsible for
the transport of materials throughout the body, the most
important being oxygen. In order for your body to get the oxygen
needed for cellular respiration, you need to breathe. Breathing
exchanges the gases needed for respiration. You inhale the O2 you
need and exhale the CO2 you don’t need. The O2 is then used to
obtain energy from chemical respiration. Without oxygen, your
body is not able to make ATP. Breathing is not respiration.
Breathing just gives you the
gases needed for respiration.
Air enters the respiratory system when you inhale through
your nose or mouth. Inhalation occurs when the diaphragm
underneath and other muscles around the chest area contract and
expand the rib cage. Inhaled air passes through a series of tubes to
reach the lungs. Within each lung, the tubes carry the air into
smaller and smaller tubes called bronchioles (see diagram). The
smallest bronchioles end in groups of tiny air sacs called alveoli,
which are surrounded by blood vessels. The exchange of gases
takes place across thin moist membranes of the alveoli. O2 leaves the alveoli and enters the blood; CO2
leaves the blood and enters the alveoli.
Excretory System
The human body uses the process of excretion to
remove liquid and gaseous wastes that are produced by its
chemical reactions. By removing wastes and toxic chemicals,
excretion enables the body to maintain homeostasis. When you
sweat, your skin excretes excess water, salts, and some nitrogen
wastes. CO2 and water are excreted as you exhale. The liver is
responsible for filtering toxins and dead red blood cells from the
blood. The blood also carries other cellular wastes to the
kidneys, the primary organs of excretion.
Your kidneys are responsible for filtering your blood and
reabsorbing nutrients. They are able to complete this through a
series of structures called nephrons (see diagram). After the
blood is filtered by the nephrons in the kidneys, the resulting
solution is called urine. It is
made up of urea – a nitrogen
containing waste product released into the blood by the liver. Urine also
includes excess water, salts, amino acids, and glucose. The urine produced
by the kidneys flows through a tube called the ureter, which leads to the
urinary bladder. This is a muscular organ responsible for storing urine
until it exits the body from the urethra (see diagram).
Copy and complete the following in your notebook:
1. Explain the importance of the respiratory system.
2. Explain the importance of the excretory system.