Download Chapter 22: Body Organization and Structure

Chapter 22: Body Organization and Structure
Section 1: Body Organization
Recall: The maintenance of a stable internal environment is called
homeostasis. If homeostasis is not maintained, cells are often damaged and
can die from the damage. These cells make up tissues, so in effect the tissues
can die and as the organization levels occur, the organism can ultimately die.
Tissue Types
There are four types of tissue: 1) Epithelial Tissue – this tissue covers and
protects underlying tissue 2) Nervous Tissue – this tissue sends electrical
signals from the point of a stimulus to the brain in order to react to the
stimulus if necessary 3) Skeletal Muscle Tissue – this tissue is made of cells
capable of contracting and relaxing that can produce movement within or of
our body 4) Connective Tissue – this tissue joins, supports, protects,
insulates, nourishes, and cushions organs and keeps organs from falling
apart.
Recall that two or more tissues working together will form an organ. Our
stomach has all four types of tissues that make it up (the stomach therefore is
an organ). The stomach has blood vessels which is connective tissue, it
contains epithelial tissue to cover the lining, it has nervous tissue (tell us
when we are hungry or full), and it contains muscle tissue that expands and
contracts to break up the food we ingest (eat).
Recall organs make up organ systems. When any organ fails, the body’s
organ systems can fail. We have 11 organ systems.
The 11 Organ Systems (We will look at these in great detail)
1: Integumentary System – made up of our skin, hair and nails. This system
helps protect underlying tissue(s).
2: Muscular System – Your skeletal muscles move your bones and this
allows us to move from one place to another if our body is functioning
properly.
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3: Skeletal System – this is made up of your bones. Our bones provide
support. If we didn’t have bones we would be one ugly blob with no shape.
4: Cardiovascular System – composed of our heart, and blood vessels
(arteries and veins). Transports blood with nutrients and wastes.
5: Nervous System – this system sends electrical impulses throughout our
body (nerves, spinal cord, and brain).
6: Lymphatic System – this system includes lymph nodes and lymph vessels
and helps us with immunity and getting rid of germs.
7: Digestive System – Breaks down food we eat into nutrients that our body
can use.
8: Endocrine System – Composed of glands that secrete hormones (chemical
messages) for specific actions in our body (pituitary gland, thyroid gland and
testies for males, and ovaries for females to name a few of the glands in our
body).
9: Respiratory System – our lungs absorb oxygen and release carbon
dioxide.
10: Urinary System – removes wastes from our blood and regulates fluids in
our body.
11: Reproductive System: In males it produces and releases sperm. In
females it produces eggs and provides a development site for an unborn
baby.
Review
1. Explain the organization level and relationship between cells, tissues,
organs, and organ systems.
2. Compare the four types of tissues and their function.
3. Without looking at your notes, make yourself a chart listing all of the
major organ systems and their function.
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Answers to Review
1. Cells make up tissues, tissues make up organs, organs make up organ
systems and organ systems is what make up an organism. Cells work
together to make tissues. Tissues work together to make organs.
Organs work together to make organ systems. Organ systems make up
organisms.
2. Nervous Tissue – sends electrical signals (impulses) for stimuli,
Epithelial – covers and lines in order to protect underlying tissue,
Muscle – cells contract and expand to produce movement, Connective
Tissue – joins, supports, protects, insulates, nourishes, cushions, and
keeps organs from falling apart.
3. Compare your chart to the notes you have learned.
Applying what you learned
Think of a time when homeostasis in your body was disrupted. Which
body system(s) were affected? Explain your reasoning.
IMPORTANT: As we learn details about each system always make yourself
learn the NAME, LOCATION, and FUNCTION. Example: Name: nervous
system, Location: spinal cord, nerves, brain, Function: to send electrical
impulses for reactions to stimuli or other needed reactions (walking, talking,
etc.).
Section 2
The Skeletal System
Our bones and cartilage and the special structures that connect them make
up our skeletal system. If we did not have our skeleton for support we would
be a mass or blob so to speak. Our skeleton or bones are living cells. They
must be nourished because they are made up of cells. These special cells are
called osteocytes and they mage up our bone tissue.
Functions of Our Bones
1) Protection - the vital organs in our chest (heart and lungs) are
protected with our ribs, our spinal cord is protected by our vertebrae,
and our brain is protected by our skull.
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2) Storage - bones store minerals that help the nerves and muscles
function properly. Your arm and leg bones store fat that can be used
for energy.
3) Movement – Muscles pull on the skeleton in specific locations to
produce movement. Without the bones we also could not sit, stand,
walk, or run.
4) Blood Cell Formation – Some of our bones are filled with marrow that
produces blood cells.
Bone is composed of connective tissue and minerals that are deposited by
living cells called osteoblasts. If we looked at a section of our longest bone
(the femur) in our thigh, we would find spongy bone and compact bone.
These are found in all of our long bones. Compact bone is dense and has no
visible openings. Spongy bone appears to look like a real fine sponge with
air spaces. Spongy bone is where we get most of the strength for our bones.
The “spongy” configuration acts as a truss structure analogous to what we
would see in a building made of steel.
Marrow
The soft tissue in the bone is called marrow and red marrow produces
red blood cells.Yellow marrow found in the center of the bone (central
canal) of long bones stores fat. The canals in the compact bone contain small
blood vessels.
Bone Information
Most bones start out as soft, flexible tissue called cartilage. As a new born
baby, we had very little bone. We were mostly cartilage. As we became
older, the cartilage was replaced by bone.
The location where two or more bones connect is called a joint. These joints
have unique designs that will allow movement from some joints and little or
no movement from others. Joints that are freely moving are more susceptible
to injury than those that are less flexible.
Joints are held together by ligaments that are connecting bone to bone. A
strained ligament will heal if given time, but a torn ligament must be
repaired surgically. Most bones also have cartilage on the ends to help
cushion the area where two bones meet. When this cartilage is worn away,
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the joint becomes arthritic. This can create discomfort for the individual with
arthritis.
Types of Joints
1. Sliding Joint – this type of joint allows some movement of flexibility.
The bones in this type of joint glide over each other. Example: the
bones in your wrist.
2. Ball and Socket – this operates like a joystick on a computer game,
the joint is free to move in all directions. Example: your shoulder
joint.
3. Hinge Joint – this operates like a hinge on a door. Example: Knee
joint, knuckles, toes, jaw and elbow joint.
How Bones Function to Help Movement
Bones function like a simple machine called a lever. The lever has three
parts: fulcrum, effort, and the load. The effort is the force applied to the
lever, the fulcrum is the pivot point and the load is the resistance. There are
three classes of levers:
First Class Levers: have the effort on one end, the load on the other with the
load on the other and the fulcrum located in the middle.
Effort
Fulcrum
Load
/\
Example: Your neck serves as the fulcrum and the muscles on the back of
your neck serve as the effort to tilt your head back (upward), the load would
be the front of your head (face region).
Second Class Levers – have the fulcrum on one end and the effort on the
other with the load close to the effort.
Fulcrum
Load
Effort
/\
Example: If you raise your heel off of the floor, your toes are the fulcrum
and the effort is the muscles on the back of your leg, the load is the “weight”
exerted from your body to the middle or arch portion of your foot.
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Third Class Lever – the effort lies between the load and fulcrum.
___________________________Effort
Load
/\ (Fulcrum)
Example: Holding your forearm parallel to the floor and having your upper
arm 90 degrees to the floor. While doing this imagine having something in
your open hand like a cup. Your elbow serves as the fulcrum and the
muscles on your forearm serve as the effort while lifting the cup with your
hand and holding the rest of your arm stationary.
Review
1. What are the important functions of bones?
2. Draw a long bone like a femur that has a section removed and label
the parts (spongy bone, compact bone, areas for blood vessels,
marrow cavity, and cartilage).
3. List three hinge joints in your body.
4. Are bones living? What do bones begin as? What do we call the cells
that deposit bones? Where are red blood cells produced? Some bones
store fat, what is it used for?
5. What is a function of cartilage on the ends of bones?
Answers
1. Bones provide support, store and release minerals, enables us to move
our bodies, and make blood cells.
2. Compare your drawing to the bone on page 527 in our classroom text.
3. Hinge joints can include the elbow, knee, jaw, knuckles and toes.
4. Bones are living, they require nourishment like other tissues in our
body. Bones start out as cartilage. The cells that deposit bones are
called osteoblasts. Red blood cells are produced in the red marrow.
The fat can be used as a source for energy.
5. Cartilage can serve as a cushioning source when it is located at the
end of long bones.
Section 3
The Muscular System
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Muscles attach to bones and the connective tissue that attaches them make
up the muscular system. Remember: Muscles ALWAYS contract to do
work. In other words, for muscles to do work, the muscle fiber must contract
(get shorter).
Types of Muscle Tissues
1) Smooth Muscle – this is found in the digestive tract and your blood
vessels. 2) Cardiac Muscle – this is heart muscle (found only in the muscle
tissues of your heart). 3) Skeletal Muscles – these are the muscles attached
to your bones for movement and protecting inner organs.
Voluntary or Involuntary Muscle
Muscles that are under your control are voluntary muscles. The
muscles used to pick up a pencil when you want to write are voluntary
muscles (you are controlling their actions). Muscles that digest food, move
food through your digestive system (smooth) and cardiac muscles are
examples of involuntary muscles (you do not have to think about making
these muscles take action).
Some may fall into voluntary and involuntary (example: eyelids –
sometimes you control your blinking, other times you blink and do not
realize you have blinked).
Working Muscles
When you want your muscles to contract and make you walk you
must have electrical signals traveling from your brain to your muscle cells.
The muscle cells respond by contracting (shortening). Remember, muscles
only do work when their fibers are contracting.
Muscles to Bones
Your skeletal muscles are attached to your bones by a connective
tissue called tendons. When the muscles contract, they get shorter and bring
the bones closer to each other, hence producing movement.
Muscles always work in Pairs
Muscles work in pairs, resulting in smooth controlled movements.
Example: Your Biceps (upper arm muscle in the front) can contract and
cause our arm to bend at our elbow. The triceps (back of upper arm) can
contract to straighten our arm back out. The muscle that is causing the
bending movement is called the flexor, and the muscle that straightens out a
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part of the body is called the extensor. So in the above example, the biceps is
the flexor and the triceps is the extensor.
Use It or Lose It
If you do not use your muscles, the muscle tissue will deteriorate. We
must use our muscles in order to keep them “tone” and in order to build
them up and become stronger. If you know someone with a broken bone and
they wear a cast, the muscles not being used will become weaker and will
have to be strengthened when the cast is removed.
Muscles also aid in the circulation of blood and lymphatic fluid. When
muscles contract, the action constricts the vessels and “pushes” blood and
lymph in their respected vessels. This helps blood flow without extra effort
from the heart.
Exercise
In order to maintain muscle or build muscle, we have to be active and
exercise. The most effective exercise is resistance exercise. This is where the
muscle contracts to move an object and the object offers resistance. The
process of lifting our bodies vertically offers one method of resistance. An
example of this type of exercise would include climbing steps, push-ups, situps, pull-ups and other motions that use our own weight as the resistance
weight. Resistance exercises are often hard to maintain long periods of time,
but they offer one of the best methods of building muscle.
Aerobic Exercise
Aerobic – with oxygen. Aerobic exercise is great for our
cardiovascular system. This strengthens the heart muscle and will increase
the lung capacity and the effectiveness of our lungs. Aerobic exercises do
not necessarily strengthen skeletal muscles, but increases our endurance.
Damaging Muscle Tissue
Before taking part in any physical exercise program, our muscles need
to be warmed and stretched. Stretching can do this. Taking in deep breaths
while stretching also increases the oxygen content in our bodies. After
stretching and giving our muscles a warm-up reduces the chance for a
muscle injury. When we “pull a muscle” we may be straining it or the
muscle fibers can actually tear. We can also damage tendons. The tendons
can become inflamed (irritated) and the area may feel warmer than the
surrounding tissue. This type of tendon injury is called tendonitis.
Anabolic Steroid Use
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This has become all too common in the area of sports. Taking the
anabolic steroids can make our muscles larger and stronger and gives many
athletes an unfair advantage. We are now seeing the effects of using anabolic
steroids. Many athletes have died from having an enlarged heart as well as
other complications from using anabolic steroids. If a person has not fully
developed it may also cause bones to stop growing, high blood pressure,
kidney failure and liver and heart problems. Anyone taking these steroids are
at risk for an early death or a very unhealthy life due to the negative affects.
Review
1: What are the three types of muscle tissue and give a few locations you can
find each type. Give the main functions of each type of muscle tissue.
2: What are the differences and similarities between resistance and aerobic
exercising and give a few examples of each. Can they both be the same in
certain instances?
3: Describe or explain how the muscles in your arm allow you to pick up a
glass from a table to your mouth for a drink.
Answers:
1: Smooth muscle tissue helps move materials through the digestive tract
and blood vessels; cardiac muscles cause the heart to beat; and skeletal
muscles enables bones to move.
2: Resistance exercises increase our strength of skeletal muscles. Resistance
exercises involve overcoming weight of some type. Aerobic exercises
improve the condition of heart muscle and increase our endurance.
3: Our biceps contract in order for our arm to bend and bring the glass up to
our mouth to drink. Our triceps contract in order to straighten our arm
back out and set the drink back onto the table.
Section 4
The Integumentary System
The integumentary system is for protection and includes our hair, nails, and
skin. Our skin is the largest organ of all the organs our bodies have.
Integumentary means covering. The integumentary system also helps
your body to maintain homeostasis. Remember from chapter 1:
homeostasis is a stable internal environment.
Functions of the Skin
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1) Protects our bodies from evaporation and helps keep foreign
particles out of the body.
2) Keeps us in “touch” with our environment. The nerve endings
in our skin allow us to fell what is around us.
3) Our skin helps to maintain our body temperature. We have
sweat glands in our skin that will sweat and when the sweat
evaporates, it cools our body.
4) Our skin also helps rid our bodies of waste products from the
blood stream by way of the sweat.
Skin Color
A pigment in our skin called melanin determines the color of our skin.
If we have a lot of melanin, our skin is very dark. If a small amount of
melanin is produced, our skin will be very light. Melanin in the upper layer
of the skin protects us by absorbing much of the ultraviolet radiation from
the sun, which reduces the DNA damage that can lead to cancer. All of our
skin is susceptible to cancer so protection should be taken when we spend
time outside. Proper skin suntan lotion should be used and the lotion should
contain a SPF protection of at least 30.
Layers of Skin
The skin is the largest organ of our body and it has two layers. The
epidermis is the upper layer and is thinner than the second layer. “Epi”
means above or top. The deeper layer is called the dermis. It is thicker than
the epidermis.
Epidermis
Composed of epithelial tissue. It is about as thick as two pieces of
notebook paper over the most of our body. Our palms of our hands and soles
of our feet have thicker layers of epidermal cells. Most epidermal cells are
dead and filled with keratin which helps the skin be tough and water-proof.
Dermis
Found beneath the epidermis. It contains many connective tissue
fibers called collagen. This provides strength and allows the skin to bend
without tearing.
Hair and Nails
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Hair is grown from the hair follicle and the portion we see is actually
dead cells. As hair grows from the follicle, cells are pushed up and form the
portion we see.
Hair protects us from ultraviolet radiation and also helps keep dust and other
particles out of our eyes and nose. Hair also helps maintain internal body
temperature. Many mammals rely on their hair to keep them warm in very
cold climates. Humans form “goose bumps” on our skin when we get cold.
This occurs when a muscle connected close to the hair follicle contracts and
the hair stands up in an erect position. The erected hairs act like a sweater to
trap heat which warms the body.
Our nails protect the ends of our toes and fingers so they can remain
sensitive to touch. Our nails grow from nail roots. The nails we see are dead
cells. As cells grow from the root, the nail gets longer.
Skin Cancer and other Problems
Sometimes skin cells become damaged and the cells rapidly multiply out of
control. When cells go through the cell cycle at a rate faster than normal we
call that cancer. This can also invade other tissues and result in cancer
spreading.
A common problem many individuals face is having hormones cause too
much oil being produced by the skin cell oil glands and creating a situation
for infections. The oil may cause skin cells and bacteria to clog up the
follicle and when the bacteria multiply you have an infection. Washing our
skin well each day can usually prevent this type of infection.
REVIEW
1: Why does skin color vary from person to person?
2: List as many structures as you can that are found in the skin and give the
function of each one.
ANSWERS
1: The amount of melanin produced regulated the skin color.
2: Hair follicle, blood vessels, nerves, oil glands, sweat glands, keratin for
water proofing and flexibility, fat cells to help conserve temperature and
can be used as energy sources if needed.
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