Download Skeletal and Muscular Systems

Skeletal and Muscular
Systems
Mr. Fox’s 7th Grade Science Class.
The Skeletal System
• A human adult has 206 bones. When
you are born, you have between 275
and 305 bones in your body.
• Each bone shares the function of the
system.
Functions
• 1. provide shape and support
• 2. enables you to move
• 3. protection of internal organs
• 4. produce blood cells
• 5. stores materials for body functions
Remember!!
• Bone is living
material
• It contains blood
vessels and nerves,
just like other parts
of your body.
Parts of the bone
• Bone Marrow – soft tissue in the center
cavity of the skeletal system.
• Cartilage – flexible, elastic, connective
tissue found in the joints
• Cushions the joints, and keeps bones from
rubbing together.
Developing Bone
• Ossification – the process of forming
bones.
• Osteoblasts form the bones
• Osteocystes maintain the cellular activity
of the bone.
• Osteoclasts break down bones.
Types of Joints
• 1. Immovable Joint (Fixed Joint) – allow
little if any movement. Joints in your
skull, ribs.
Types of Joints
• Ball and Socket - allows the greatest
range of motion. Nearly 360 degrees.
• Shoulder and Hip Joints.
Types of Joints
• Hinge Joint – Like a door hinge,
forward and backward movement.
• Knee and Elbow
Types of Joints
• Pivot (radial) Joint – allows one bone to
rotate around the other.
• Lower arm, Lower leg
Types of Joints
• Sliding Joint – allows one or more bones
to slide over another.
• Wrist, Ankle
Bone Problems
• Dislocation – when a bone moves out of
place. Usually very painful, but easily
fixed.
Bone Problems
• Break/Fracture – when bones break in
places they shouldn’t.
• Always heal back larger so they are
stronger.
Bone Problems
• Osteoporosis – When bones start losing
their density, from a lack of calcium.
• Happens more in woman
• Arthritis – A generic term describing
the inflammation of the joints. Pain,
stiffness, swelling of the joints.
Muscles
• It takes 42 muscles to frown, only 16 to
smile. Smile more and save energy.
• Your body has over 600 muscles, nearly
3 times as many as its bones.
Muscle Action
• Two types of muscle action:
• Involuntary – muscles you cannot control,
heartbeat, breathing, digestion
• Voluntary - muscles you control, smiling
moving
Types of Muscles
• Skeletal Muscles - muscles that are
attached to your bones, provide the
force needed to move.
• Striated fibers that tire quickly.
• Work in pairs to move bones, can only pull
or contract.
Skeletal Muscle
Types of Skeletal Muscle
• Ligament – skeletal muscles that hold
bones together at joints.
• Tendons – skeletal muscles that connect
muscle to bone.
• Regular Muscle – Muscles that do most
of the work in moving the bones.
Types of Muscle
• Smooth Muscle – often line the interior
of body organs, stomach, intestines, not
striated, are involuntary, do not tire
easily.
Types of Muscle
• Cardiac Muscle – Heart muscle, striated
but involuntary, does not tire!
Muscle at work
• Muscles can only contract, not extend.
• Must work in pairs.
• One muscle contracts the other muscle
in the pair returns to its original state.
How on the muscle level
• A muscle contracts when ATP causes
thin filaments (actin) in muscles fibers
to slide over thick filaments (myosin).
myosin
actin
actin
myosin
Skin!!!
The Skin
• Everyone… your epidermis is showing!
• The skin is the largest organ in the
body! And the most visible.
Functions of the skin
• Major functions of the skin:
• Reduces water loss
• Protection from injury and infection
• Regulates body temp.
• Eliminates waste
• Sense the environment
• Produces vitamin D from sunlight
Structure of the Skin
• Epidermis – top layers of skin, no blood
vessels or nerves, surface cells are dead,
skin pigment (melanin) is found in the
lower epidermis
• Dermis – lower layers of skin, contains
blood vessels, nerves, sweat glands,
hair follicles, oil glands, and hair.
Skin Diseases
• Eczema – a disease of reoccurring skin
rashes and dryness. (very common not
deadly)
• Acne – (PIMPLES!!!!!) More or less the
changed of the hair follicles and
sebaceous glands cause it.
• Tinea pedis – Athlete’s Foot. Is
typically caused by mold! Up to 15% of
the U.S. population may have tinea
pedis.
Cancer
• Skin cancer – one of the many forms of
cancer, this one caused from over
exposure to UV light, and many other
things.
Homework
• Finish the chapter one review. Get
ready for a bone and muscle test next
week.
• Laury is awesome