Human Body Systems

1
Human Body Systems
2
Human Body Organization

• The Human Body
• is composed of
• Organ Systems
• are composed of
• Organs
• are composed of
• Tissues
• are composed of
• Cells

3
Circulatory System

• Major Structures
• heart, blood vessels, blood, lymph nodes and
  vessels, lymph
• Functions
• transports nutrients, wastes, hormones, and
  gases

4
Interesting Facts

• The heart is a muscle about the size of a fist.
• Each blood cell takes around 20 seconds to make
  its deliveries and travel back to the heart.
• The heart works by contracting and relaxing.
• The heart has flapping valves that allow blood to
  flow in one direction. The flaps create a
  lub-dup sound.
• A heart attack is caused by a blood vessel
  blocked by a clot.
• The average person has about 5 liters of blood.
• The body can replace blood within a few weeks
  after loss.
• Platelets in the blood help it to clot, or stick
  together, to make scabs.
• The four blood types are A, B, AB, and O.

5
Digestive System

• Major Structures
• mouth, throat, esophagus, stomach, liver,
  pancreas, small and large intestines
• Functions
• extracts and absorbs nutrients from food
  removes wastes maintains water and chemical
  balances

6
Interesting Facts

• Food takes 3 days to complete its journey through
  the digestive system.
• An adult digestive system is about 30 feet long.
• An average person takes in about 4.4 pounds of
  food and drink every day, consuming over 110,000
  pounds in a lifetime.
• Gravity and bands of muscles help food travel
  down the esophagus to the stomach, making it
  possible to eat lying down or even upside down.
• The stomach is lined with a slimy mucus and
  releases an acid called gastric juice to help
  dissolve food.
• Stomach noises are caused by food and air
  sloshing around.
• Water makes up about 70 of the body.

7
Endocrine System

• Major Structures
• hypothalamus, pituitary, pancreas, pineal,
  adrenal, thyroid, parathyroid, testes, and
  ovaries
• Functions
• regulates body temperature, metabolism,
  development, and reproduction maintains
  homeostasis regulates other organ systems

8
Interesting Facts

• Endocrine glands release hormones, chemicals that
  act as signals telling different parts of the
  body what to do.
• The body makes over 20 hormones, each with a
  different job to do.
• The blood carries hormones around the body until
  reaching the target organ, the body part needing
  it.
• Hormones can affect the way a person feels.
• As a person ages, the body makes less of some
  hormones.

9
Excretory System

• Major Structures
• kidneys, urinary bladder, ureters, urethra, skin,
  lungs
• Functions
• removes wastes from blood regulates
  concentration of body fluids

10
Interesting Facts

• Leftover waste in the large intestine is called
  fiber. Fiber sweeps the digestive system clean
  as it moves along.
• The large intestine contains millions of bacteria
  that feed on the leftovers in the bowel.
• Kidneys are located in the middle of the back.
• Each kidney contains up to a million tiny units
  called nephrons that filter all of the blood in
  the body.
• People with failing kidneys have their blood
  cleaned by a dialysis machine or have a new
  kidney transplanted.

11
Immune System

• Major Structures
• white blood cells, lymph nodes and vessels, skin
• Functions
• defends against pathogens and diseases

12
Interesting Facts

• The immune system is constantly on guard to keep
  germs, bugs, and poisons out the body.
• The skin is the immune systems first line of
  defense.
• There are germ-killing chemicals in saliva,
  tears, ear wax, and mucus.
• White blood cells destroy germs that enter
  through cuts.
• Sticky yellow pus is made of bodies of white
  blood cells that die in the battle against germs.
• An allergy is the immune system making a mistake.
• Some white blood cells make antibodies which can
  protect against bacteria, viruses, and poisons.

13
Integumentary System

• Major Structures
• skin, nails, hair
• Functions
• protects against injury, infection, and fluid
  loss helps regulate body temperature

14
Interesting Facts

• Skin cells are made of a tough protein called
  keratin.
• About 40 million dead skin cells are lost each
  day.
• The average adult skin spread out would take up
  about 2.2 square yards and would weigh around 15
  pounds.
• The skin is waterproof. It keeps water out so
  the body is not a sponge and holds in moisture so
  it does not dry out.
• Skin expands to fit the body.
• Skin forms bumps when cold and releases sweat
  when hot.
• The skin repairs itself forming scabs and scars.
• Skin absorbs sunlight to make vitamin D. Too
  much sun can lead to sunburn and can even cause
  skin cancer.

15
Muscular System

• Major Structures
• skeletal, smooth, and cardiac muscle tissues
• Functions
• moves limbs and trunk moves substances through
  body provides structure and support

16
Interesting Facts

• There are nearly 600 skeletal muscles that make
  up nearly half of the total body weight in the
  human.
• Muscles can only pull they cannot push.
• Energy is stored in the muscles in a chemical
  called ATP.
• Lactic acid is released when the muscles are
  overworked and lack O2, making the muscles hurt
  or ache.
• Muscles are attached to bones by tendons.
• The biggest muscles in the body are the gluteus
  maximus muscles (buttocks), but the muscle that
  can exert the most force is the masseter (jaw
  muscle).

17
Nervous System

• Major Structures
• brain, spinal cord, nerves, sense organs
• Functions
• regulates behavior maintains homeostasis
  regulates other organ systems controls sensory
  and motor functions

18
Interesting Facts

• The left half of the brain controls the right
  half of the body and vice-versa.
• The human brain is more powerful and complicated
  than the worlds biggest computer. It can store
  millions of memories and do billions of
  calculations every day.
• The human body has over 100 billion neurons in
  all.
• The brain can receive over 100,000 signals per
  second.
• Messages whiz through the nerves at up to 270
  mph.
• Neurons reaching from the spinal cord to the toes
  are the longest cells in the human body,
  measuring up to 4 feet in length.

19
Reproductive System

• Major Structures
• ovaries, uterus, and breasts (in females) testes
  and penis (in males)
• Functions
• produces gametes and offspring

20
Interesting Facts

• A person grows over 5 million times bigger
  changing from a single cell to a newborn human
  being.
• Humans grow for about 20 years, changing from a
  child to an adult.
• Male reproductive cells are called sperm, and
  female reproductive cells are called eggs.
• Sperm and eggs have only 23 chromosomes each.
• When joined together, sperm and egg make a whole
  cell called a fertilized egg which can grow into
  a baby.

21
Respiratory System

• Major Structures
• lungs, nose, mouth, trachea
• Functions
• moves air into and out of lungs controls gas
  exchange between blood and lungs

22
Interesting Facts

• The lungs fill up most of the chest cavity.
• The left lung is slightly smaller than the right
  lung, because it must allow enough space for the
  heart.
• Inside each lung is a network of thousands of
  tunnels called the bronchial tree which branch
  into bronchioles containing six million tiny bags
  (air sacs) called alveoli.
• The lungs take millions of O2 molecules out of
  the air and put them into the blood to be
  delivered to the cells.
• Simultaneously, the lungs also take waste gases
  out of the blood.
• A smokers lungs are dark gray and full of dirt
  and tar.

23
Skeletal System

• Major Structures
• bones and joints
• Functions
• protects and supports the body and organs
  interacts with skeletal muscles produces red
  blood cells, white blood cells, and platelets

24
Interesting Facts

• A baby is born with 270 bones while an adult body
  has 206 bones.
• The hands and feet contain half of the bones in
  the human body.
• Bones are made of the hard mineral calcium,
  living cells, blood vessels and nerves.
• Bones are made of several layers periosteum,
  compact bone, and spongy bone.
• A joint is where two bones meet.
• Joints can be cartilagenous (spine),
  ball-and-socket (shoulders and hips), pivot
  (neck), gliding (wrists), and hinged (fingers,
  elbows, and knees).