Transcript Chapter A1.2 Human Body Systems

Chapter A1.2 Human Body
Systems
The Circulatory System
• The circulatory system transports oxygen,
nutrients, and wastes through the body in the
blood.
• The liquid part of the blood, called plasma, is
mostly water.
• Plasma also contains dissolved nutrients and
waste products.
• The waste product in blood is what we call
carbon dioxide.
continued
• The solid part of blood contains red blood
cells and white blood cells.
• Red blood cells absorb oxygen and deliver it to
the organs.
• White blood cells help the body fight
infection. They attack and destroy the germs
and viruses and bacteria that enter the body.
continued
• Blood also contains platelets– tiny pieces of blood
cells inside membranes.
• Platelets cause blood cells to clot when a cut or
open wound occurs.
• They also repair damage to your blood vessels.
• The heart pumps blood through blood vessels.
The oxygen rich blood flows through the body
through arteries, and returns to the heart and
lungs through veins.
continued
• Capillaries- are blood vessels so small that the
red blood cells have to travel through single
file.
• There are capillaries throughout the body so
that oxygen can reach every part of your body.
The Respiratory System
• When you breathe, you draw air into your
lungs.
• The air is filtered by tiny hairs inside your nose
and warmed by capillaries.
• The warmed air then travels down your
trachea, or windpipe.
• The trachea branches into smaller tubes called
bronchi.
continued
• Each bronchi tube leads to one of the lungs.
• In the lungs, the tubes divide smaller and
smaller.
• At the end of the smallest tubes, there are tiny
air sacs called alveoli.
• The walls of the alveoli are only one cell thick.
• The blood coming from the heart contains
much carbon dioxide.
continued
• Carbon dioxide diffuses through the walls of
the alveoli and then into the air you will
breathe out.
• When you breathe in, the air diffuses through
the alveoli and into the red blood cells. The
oxygen rich blood then flows back to the
heart. The heart then pumps the
“oxygenated” blood throughout your body.
The Digestive System
• Digestion starts as soon as you chew your
food. Your chewing breaks the food into
smaller pieces and mixes with your saliva.
• Saliva moistens the food and begins to break
down the starchy foods into sugars.
• When you swallow, food goes through your
esophagus, a long tube from your mouth to
your stomach.
continued
• Juices in your stomach containing acid and
other chemicals break down the proteins.
• After several hours in your stomach, the
digested food moves into your small intestine.
• In the small intestine, more chemicals break
down the food. Nutrients from the food are
now able to diffuse through the villi, tiny
finger like structures, into the blood.
continued
• Undigested food then travels to the large
intestine, where water and minerals pass into
the blood, and non-needed material are
removed from the body.
• Two other organs aid in digestion. The liver
produces bile, which is stored in the
gallbladder until you need it. The pancreas
produces a fluid that calms stomach acid and
other chemicals that help complete digestion.
The Excretory System
• The waste left over from the circulatory
system must be removed from the blood. The
food material not used by the body must be
removed from the intestine. This is the job of
the excretory system.
• Cell wastes include carbon dioxide and
ammonia.
• Ammonia travels to the liver where it is
converted into urea.
continued
• The urea then travels by way of the blood to
the kidneys.
• The urea, water and other wastes then form
urine and it flows from the kidney to the
bladder through tubes called ureters.
• You empty the bladder when it is full through
a tube called the urethra.
continued
• The body gets rid of wastes in other ways too.
When you exercise you get warm and sweat.
Sweat is a salty liquid that cools your body
when it evaporates.