Download Unit:1 The skeleton, muscles and movement

Unit:1 The skeleton, muscles
and movement
Mrs: Jackie Maldonado
Skeleton
• Consist of
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backbone
spine
12 pairs of ribs
Limbs are attached to girdles
• Hip girdle (pelvic girdle) is
joined rigidly to the lower end of
the vertebral column
• Shoulder girdle (pectoral girdle)
consist of pair of collarbones and
shoulder blades
Skeleton
• Humerus and femur are fit into sockets
• Bones- defined as living tissue of living
cells plus fibers.
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Why bones needs living cells?
Resist compression-hard
Resist bending- very strong
Fibers- made of collagen
Calcium phosphate crystals
Penetrated by blood vessels. Why?
Types of bones
• Outside layer- compact bone (dense
and hard)
• Spongy bone- inside the layer.
– Consist of fine struts of bone with
spaces in between where red and white
cells are produced.
– Forms the red bone marrow found in
limbs bones, ribs and vertebrae
Compact and Spongy Bones
Vertebral Column
• Central supporting structure of the
skeleton
• 33 bones called vertebrae separated
by discs of fibrous cartilage
• Discs- allow vertebrae to move
slightly and so enable the vertebral
column to bend backwards and
forwards from side to side
Vertebral Column
Skull
• Made of many
bony plates
• Protects brain and
sense organs
• Include lower and
upper jaw
• Lower jaw
separated for
chewing
Limbs
• Legs
– Femur- attached at the hip to the pelvic girdle
by a ball joint and at the knee it makes a hinge
joint with the tibia.
– Fibula- runs parallel with the femur but does
no form part of the knee joint.
• Arms
– Humerus- upper arm attached with a joint to
the radius and ulna
– Radius and ulna- make a joint with wrist bones
which in turn joint with the five hand and
finger bones.
Functions of the skeleton
• Support- holds the body off the
ground and keeps its shape
• Protection- of brain, heart, lungs etc.
• Movement- chewing action of lower
jaw, movement of ribs cage.
• Production of blood cells
Homework
• Study the figure of the skeleton and
then write the biological names of
the following bones:
– Upper arm bone
– Upper leg bone
– Hip bone
– Breast bone
– Backbone
– Lower arm bones
Joints
• Where two bones meet
• Types of joints
– Fixed joint- like the junction of the hip
girdle and the vertebral column
– Movable joint- knee
• Ball and socket joints- allow movement
forward, backwards and sideways (hip and
shoulder)
• Hinge joints- allow movement in only one
direction. (elbow)
Joints
• Friction between bones is prevented by a
smooth cartilage and the synovial fluid
• Smooth cartilage- firm but softer than
bone. Contain fibers but no mineral salts.
• Movable joints are also called synovial
joints
• Bones forming the joint are held in place
by tough bands of fibrous tissues called
ligaments
Muscles
• Three main types
– Skeletal muscle (striated or
voluntary)
• Made of long fibers form with
many cells fused together.
Nuclei can be observed.
• Muscle fibers are arrange in
bundles which form distinct
muscles
• Most are attached to bones
producing movement
• Each has a nerve supply. When
a nerve impulse is send to the
muscle the muscle contract
• We can control it.
Muscles
– Smooth muscle
(unstratiated or
involuntary)
• Make layers of muscles
tissue instead of distinct
muscles.
• Found in the walls of the
alimentary canal, uterus
and arterioles.
– Cardiac muscle- only in
the heart
Muscles and movement
• The ends of the limbs muscles are drawn
out into tendons which attach each end of
the muscle to the skeleton.
• The tendon at one end is attached to a
non moving part of the skeleton while the
tendon at the other end is attached to the
movable bone close to the joint
• When the muscle contracts it pulls on the
bones and makes one of them move.
Tendons
Muscles and movement
• Limbs muscles are usually arrange in
pairs having an opposite effect
• Antagonistic muscles- example
biceps and triceps
• Brain send impulses to control
contraction or relaxation
Muscles and movement
Muscular activities other
than locomotion
• Chewing
• Breathing
• Throwing
• Swallowing
• Blinking
Homework part II
•
Answer the following questions
1. Apart from the elbow and knee, what other
joints in the body are hinge joints.
2. Apart from its structural and mechanical
functions, what other important function
does the skeleton have?
3. Which parts of the skeleton are concerned
with both protection and movement?
Energy for muscle
contraction
• Comes from respiration
• Resting muscles has a store of
glycogen
• During exercise glycogen is replenish
from the glucose in blood.
• During exercise there is an increase
in the volume of blood= stroke
volume
• Vigorous exercise results in
anaerobic respiration-lactic acid
Energy for muscle
contraction
• The heat generated in the reaction
may trigger a change in temperature
and thus sweating.
Long term benefits of
exercise
• Resting heart rate goes down
• Muscles used in exercise grow larger
• More enzymes are made in the muscle
tissue
• Ligaments and tendons become stronger
• Joints become more flexible
• Protection from heart attack
• Well-being-you will feel good
Injuries to joints and
muscles
• Sprains- ligaments partially torn
• Strains-fibers tear apart
• Dislocation- bones at a joint become
displace
• Fractures- a limb bone is broken
Homework