Download Cells

Cells
 basic building block that
makes up all living things
 the smallest part of a living
thing that can carry out all the
process of life
 can carry out all the processes
of life:
o breathe
o take in food and turn it
into energy
o grow and develop
o get rid of waste
o respond to their
environment
o reproduce
o move
unicellular
organism
 an organism made up of only
one cell
 simplest forms of life
 carry out the basic process of
life – can move, find food, and
grow
 can reproduce
 remove waste by moving
them to the outside of their
cells
bacteria
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unicellular
found everywhere
3 basic shapes – rod, round, spiral
billions in your body
some bacteria are helpful while
others are harmful
amoeba
 unicellular
 eats by surrounding a food
particle and then bringing the
food into the cell
 moves by changing its shape
paramecium
 unicellular
 has many hair-like structures
called cilia that help it move
and take in food
 found mainly in lakes, ponds
and puddles
euglena
 unicellular
 has a whip-like part that
moves it forward
 uses sunlight to take in food
multicellular
organism
 an organism made up of 2 or more cells
 each cell does a different job
 each cell has a shape and structure that helps it
do its job
 example – nerve cells are long and thin; their
shape helps to send signals to other cells
 groups of cells of the same type work together
to perform certain functions
 take in food and water, reproduce, grow, move,
get rid of waste, die
 Most have cells that are not able to exchange
gases with the outside environment
tissue
similar cells that work together to perform a task
organ
a group of tissues that work together to do a certain
job
organ
system
a group of organs that work together to perform one
or more functions
cells
tissue
organ
organ system
organism
Circulatory System
Includes the heart and blood vessels
Body’s transportation system
Moves oxygen and nutrients to each cell
Takes away cell’s waste
Three types of blood vessels - arteries, veins and capillaries
o Arteries carry blood away from the heart
o Veins carry blood from cells to heart
o Capillaries connect arteries and veins; smallest blood vessel with
thin walls so gases (oxygen and carbon dioxide) can pass
through
 Heart has 4 chambers – right atrium, left atrium, right ventricle and left
ventricle
 Oxygen-rich blood enters the heart from the lungs and goes out into
the body
 Oxygen-poor blood enters the heart from the body and goes out to
the lungs
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Respiratory System
 respiratory system takes in oxygen from the air that you breathe.
 you breathe air in through your nose or mouth
 air travels down throat and passes through your trachea (or windpipe).
 Trachea leads to two branches called bronchi that go into the lungs.
 bronchi (bronchus) let air in and out of your lungs so you can breathe
 bronchi branch into smaller tubes called bronchioles
 bronchioles end in clusters of tiny thin-walled alveoli, or air sacs, in the
lungs - oxygen enters the blood and carbon dioxide leaves the blood.
 when you breathe out, carbon dioxide leaves your body
 Your diaphragm is dome-shaped muscle below the lungs. It tightens
and relaxes to make you breathe in and breathe out
Digestive System
 Digestion is the process by which food and drink are broken down into
their smallest parts so the body can use them to build and nourish cells
and to provide energy
Direction food goes: mouth – esophagus – stomach – small intestine – large
intestine
 MOUTH - Digestion begins in your mouth when you chew. Saliva begins
the breakdown of food.
 ESOPHAGUS - Muscles contract in waves to move the food down the
esophagus.
 STOMACH - food is mixed with chemicals that help break it down. (An
adult’s stomach can hold about 1.5 liters of material)
 SMALL INTESTINE - Next, food goes to the small intestine where more
chemicals continue to break down food. Nutrients are then absorbed
by the body.
o three organs help the small intestine gather the nutrients:
pancreas, liver, gall bladder
 LARGE INTESTINE - Water is removed from food and taken into the
body. Any remaining food that has not been digested becomes
waste. Food the body can’t use is stored in the large intestine.
Nervous System
 made up of the brain, spinal cord and nerves
 controls all other body systems
 two main parts of the nervous system
o Central Nervous System
 brain and spinal cord
 brain has three parts
 cerebrum
 cerebellum
 brain stem and medulla
o Peripheral Nervous System
 delivers messages from the central nervous system to the
rest of the body
 neurons transmit messages throughout the body
 Two types of nerves
o central nerves – carry information to the central nervous system
o motor nerves – carry information from the central nervous system
to other parts of the body
Muscular System
 voluntary muscles – muscles that can be controlled with the mind
 involuntary muscles – These don’t need the brain to send them
messages. You can’t control them.
Three types of muscles:
 Smooth Muscles – involuntary muscle that are in sheets or layers with
one layer of muscle behind the other.
o Examples - Your stomach muscles work to digest your food. The
muscles in your eyes keep the eyes focused. The muscles at the
bottom of the hairs on your arms will make your hairs stand up
when you are cold.
 Cardiac Muscle – heart – works to pump blood throughout your body.
Your heart is an involuntary muscle.
 Skeletal Muscles – voluntary muscles that help you kick a ball, lift a
pencil, etc.
Skeletal System
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Skeletal system is made up of bones, ligaments and tendons
Adult has 206 bones. Babies are born with about 300 bones. Their bones fuse (grow
together) as you get older.
Jobs of the skeletal system
o supports the body
o helps you move
o stores calcium and other minerals until the body needs them
o protects internal organs
 skull protects brain
 ribs protect heart and lungs
o produces blood cells – made by bone marrow which is found at the center
of the bone
Joints hold your bones together and allow them to move
o ball and socket – allow for lots of movement in every direction (example –
shoulder and hips)
o hinge – allows forward or backward motion (example – elbows, knees)
o gliding – one bone slides over enough (example is wrist or ankle)
Tendon –tissue that connects muscles to bones so the bones can move. The
tendons and muscles work together to control joint movement
Ligament – connects bone to bone and helps to stabilize the joints they surround.