Download Saint Pedro Poveda College Grade School Department Science and

Saint Pedro Poveda College
Grade School Department
Science and Health 4
Session 4 Handout
The Skeletal and Muscular System
Functions of the Skeletal System
The skeletal system protects the body's most important organs
and tissues. That is the job of your skull, ribs, and backbone. These
bones protect the softer tissue underneath them from being damaged.
The skull surrounds the brain and keeps it safe when your head hits
the ground. Your ribs surround your heart and lungs and keep them
from being hurt when a ball hits you in the chest. Your backbone
surrounds your spinal cord, a bundle of nerves that connects your
brain to the rest of your body. Bones manufacture blood cells and
store important minerals.
The skeletal system also gives your body structure. It determines
your height and the shape of your face. It is a frame for muscles and
tendons to attach to. Without bones, all of the soft tissues in your body
would fall on top of each other in a big, jiggling mass!
Composition of the Bone
Bones are made of a mix of hard materials that gives them
strength and tons of living cells which help them grow and repair
themselves. Like other cells in your body, the bone cells rely on blood
to keep them alive. Blood brings them food and oxygen and takes
away waste. Many bones are hollow. Their hollowness makes bones
strong and light. The bone marrow at the center of most bones makes
new red and white blood cells. Red blood cells ensure that oxygen is
distributed to all parts of your body and white blood cells fight germs
and diseases.
The human skeleton consists of 206 bones. We are actually born
with more bones (about 300), but many fuse together as we grow up.
These bones support our body and allow us to move. Bones contain
a lot of calcium (an element found in milk, broccoli, and other foods).
The longest bone in our bodies is the femur (thigh bone). The
smallest bone is the stirrup bone inside the ear. Each hand has 26
bones in it. Your nose and ears are not made of bone; they are made
of cartilage, a flexible substance that is not as hard as bone. Cartilage
is a connective tissue present at the ends of bones at joints. Cartilage
enables the ends of bones to move smoothly against each other.
Strong cord-like elastic tissues called “ligaments” connect bones at
joints, holding the bones in place.
Types of Joints
1. The fixed joint of the skull does not move.
Example: skull
2. A ball and socket joint allows movement in all directions (360˚)
Example: shoulders and hips
3. The hinge joint moves in one direction only. It is like the hinge on a
door that allows the door to open just so far and then close again.
Example: fingers and toes
What will happen if there are no joints in our body?
______ Joints are found in places where two bones meet. They make
the skeleton flexible — without them, movement would be impossible
Taking Care of Bones
Taking care of your bones isn't hard to do. Here are some tips:
• First, be sure to protect those skull bones (and your brain inside!) by
wearing a helmet every time you ride your bike.
• When you go skateboarding, in-line skating, or using your scooter,
be sure to add wrist supports and elbow and knee pads - the bones in
these places will thank you if you have a fall!
• If you play a sport like football, soccer, or ice hockey, always wear all
the equipment required for the sport.
• Take care of your skeleton by drinking milk and eating other dairy
products (like low-fat cheese, frozen yogurt, and ice cream, for
example). All of these foods contain calcium, which helps bones
harden and become strong.
The Muscular System
The human muscular system is made up of more than 600
muscles. Muscles are very important tissues in the body that perform
a wide range of functions. Without muscles, we would not be able to
walk, run, or move. The contraction and relaxation of muscle cells
produces movement.
Two Groups of Muscles
Muscles that we can control with conscious thought are called
voluntary muscles.
The other group of muscles are the automatic or involuntary
muscles . We don’t have to think about their action. Muscles that
move food through our digestive system or keep our hearts beating
are involuntary muscles.
Muscle Type
Skeletal muscle
Smooth muscle
Three Kinds of Muscle
Location
Control
attached to the bones voluntary
for movements
found inside organs involuntary
such as the stomach,
intestines, and blood
vessels.
Muscle of the heart
involuntary
Cardiac muscle
(hardest
working
muscle)
Voluntary muscles receive the signal to contract or relax from the
brain.
Care for the Muscles
Eating a well balanced diet is very important. Muscle growth and
maintenance require adequate protein, carbohydrates, and a number
of vitamins and minerals
It is also important to rest tired or overly exerted muscles. To keep
muscles fit, regular exercise is essential!
Stay away from substances that have negative effects on the body
such as drugs, alcohol, and unhealthy foods.
Skeletal and Muscular Disorders
Directions: Using textbooks, and the internet, research the disorder
in the left column. Then match it to its description. Finally match the
common treatment to the injury. Write the correct letters and numbers
only.
fracture
contusion
rickets
strain
cramp
Description
___c______
___a______
___d______
___b______
___e______
Treatment
____5_____
____4_____
____2_____
____3_____
____1_____
Description of the Problem
A. An injury to soft tissue such as muscle. Often caused by a blow.
Sometimes referred to as a bruise.
B. Slight pain or muscle stiffness resulting from muscles being
overworked or overstretched.
C. A break in a bone.
D. Defective formation and softening of bones.
E. A painful involuntary muscle contraction.
Possible Treatments
1. Relieve pain by massaging the affected part until muscles become
soft and relaxed.
2. Exposure to sunlight.
3. Rest is essential and cold compress may be placed on the injured
part.
4. Cold packs help reduce swelling. If serious see a doctor.
5. See a doctor immediately. Immobilization through a cast or splint is
necessary. Serious fractures may require surgery.
Reference: http://pa.slu.edu/pdf/mrbonesforcsd.pdf