Transcript Physiology - cloudfront.net

Physiology
Ms. Samuelian
Body Organization
The maintenance of a stable internal environment is called
homeostasis
If homeostasis is disrupted, cells suffer and sometimes die
Many different “jobs” have to be done to maintain homeostasis
A group of similar cells working together forms a tissue
Two or more tissues working together form an organ
Organs working together make up an organ system
The Skeletal System
Bones, cartilage, and the special structures that connect them make up
your skeletal system
Most bones start out as a soft, flexible tissue called cartilage
Cartilage contains mostly water, which gives it a rubbery texture
The place where two or more bones connect is called a joint
Skeletal Muscles
The muscles that move bones are called skeletal muscles
They help protect your inner organs
Skeletal muscles are attached to bones by tough tissues called tendons
Working in Pairs
Your skeletal muscles work in pairs to cause smooth, controlled
movements
Many basic movements are the result of muscle pairs that cause
bending and straightening
Did You Know?
It takes 13 muscles to smile
It takes 43 muscles to frown
The Cardiovascular System
The cardiovascular system transports materials to and from your cells
Blood supplies the cells of your body with oxygen
Blood is about 55% plasma and 45% red
blood cells, white blood cells, and platelets
Plasma is the fluid part of the blood
Red blood cells supply your cells with oxygen
White blood cells defend the body against pathogens (bacteria, viruses,
and other microscopic particles that can make you sick)
When you cut your skin, you bleed because your blood cells have been
opened
As soon as bleeding occurs, platelets begin to lump together in the
damaged area and form a plug that helps reduce blood loss
Circulatory System
The circulatory system consists of the heart, blood vessels, and blood
The heart pumps the blood through the blood vessels
Blood flows through the system in just one direction
Heart valves prevent blood from flowing backward
Heart
Your heart is a muscular organ about the size of your fist
The heart pumps oxygen-poor blood to the lungs and oxygen-rich
blood to the body
Your heart has a left side and a right side separated by a wall
Each upper chamber is called an atrium
Each lower chamber is called a ventricle
Blood Vessels
Blood travels throughout your body through blood vessels
A blood vessel is a hollow tube that transports blood
There are three types of blood vessels: arteries, capillaries, and veins
Arteries are blood vessels that direct blood away from the heart
Capillaries are the smallest blood vessels in your body
Veins are blood vessels that direct the blood back to the heart
Blood Flows Under Pressure
The force exerted by blood on the inside walls of a
blood vessel is called blood pressure
Did You Know?
Smoking is the leading cause of cardiovascular diseases and lung
diseases
The Respiratory System
“Out with the Bad Air; In with the Good!”
Your body needs a continuous supply of oxygen in order to obtain
energy from the foods you eat
Respiration is the process by which a body obtains and uses oxygen
and gets rid of carbon dioxide and water
Breathing is made possible by the respiratory system
The respiratory system consists of the lungs, throat, and passageways
that lead to the lungs
Digestive System
Your digestive system breaks down the food you eat into nutrients
that can be absorbed into your body
Excretory System
The excretory system
filters wastes from the
blood
Excretes the wastes
from the body in
urine
The Nervous System
What do the following events have in common: you hear a knock at
the door, you write a book report, you feel your heart pounding after
a run, you work a CAHSEE math problem, and you enjoy eating a
sweet mango with chili powder. These events are all activities of your
nervous system
The nervous system gathers and interprets information about the
body’s internal and external environments and responds to that
information
The nervous system keeps your organs working properly and allows
you to speak, smell, taste, hear, see, move, think, and experience
emotions
Time for Bill Nye
Bodies Need Antibodies
The immune system defends your body against pathogens, such
as viruses or bacteria
Your immune system’s reaction to infection is called the
immune response
Proteins on the surface of pathogens are called antigens
Antibodies stick to antigens to disable and help destroy the
pathogens
Be nice to your immune system!
White blood cell vs. Bacteria
Antibodies
So, pathogens (the bad guy) are covered with proteins called
antigens
Your B cells shift to “attack mode” when pathogens invade
your body by releasing antibodies (the good guy)
Antibodies have two antigen-binding sites
Antibodies bind with the pathogen and as a consequence
the pathogen can no longer harm the body
Immunity
Immunity
When you’ve been exposed to a pathogen and you’ve
produced antibodies to it, some of the B cells
“remember” how to produce antibodies for that
pathogen
So if the same pathogen enters the body a second time,
antibodies will be ready for the attack and destroy the
pathogens before it can multiply and cause disease

Vaccination
Vaccinations protect you from specific diseases that can
make you very sick, disable or even kill you
They boost your body's own defense system, which is
also called the immune system
Vaccines create immunity that protects you from an
infection without causing the suffering of the disease
itself
Sometimes vaccines are called immunizations, needles
or shots.
Body War I
Your Worst Enemy: Bacteria or Virus?
Type of
Pathogen
What It Is
How It
Causes
Disease
How The Body
Responds
How
Infections
Are
Treated
Virus
Too small to be seen by
the naked eye. They
can't multiply on their
own, so they have to
invade a 'host' cell and
take over its machinery
in order to be able to
make more virus
particles
Invade and
destroy cells
Your infected cells
produce special proteins
called “interferons” that
don’t have the power to
kill viruses but they do
prevent viruses from
replicating and damaging
more cells
Antiviral
drugs
Bacteria
Bacteria are organisms
made up of just one
cell. They are capable of
multiplying by
themselves
Breaks down
tissues for
food or
releases toxins
Your body’s reaction may
be an inflammatory
response due to tissue
damage caused by
infection. White blood
cells eat up invading
bacteria
Antibiotic
drugs
Do Cell Phones Have Dirty Cells?