Skeletal System
• What makes up the skeletal system?
– Bones (& connective tissue) made up of living
and nonliving material
– Cartilage-no blood vessels
– Tendons (attach muscle to bone)
– Ligaments (attach bone to bone)
Functions
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Support and shape
Protect organs
Provide a system of levers (mov’t)
Mineral reserve (Ca & P) store fat
Site of blood cell formation (marrow)
Bone Marrow
• Yellow Marrow
– Blood vessels
– Nerve cells
– Fat cells
• Red Marrow
– Produces red blood
cells
• (erythrocytes)
– Produces white blood
cells
• (leukocyteslymphocytes)
– Other elements
• (platlets-thrombocytes)
Development of Bone
• Chondrocytes- cartilage cells
• Cartilage- connective tissue. Found where
needed. (nose, ears, voice box, windpipe, ends
of bones, ribs)
• 3 Types of cartilage:
– Elastic-flexible
• (ears)
– Hyaline-loose collagen, not too strong
• (end of nose, ribs, bones, joints)
– Fibrocartilage- densely packed, tough
• (Intervertebral disks, pubis symphasis)
Development continued
• Replacement bone- cartilage model of
what bones will look like
– Newborns are mostly cartilage
– Cartilage is replaced by bones about two
months in utero.
– Ossification is the process where cartilage is
replaced by bone.
• Mineral deposits lay down near center
• Bone tissues form OSTEOCYTES (bone cells) that
replace cartilage.
Growth of bones
Structure of Bones
• Bones are made up of
living and nonliving
material.
• Periosteum– tough membrane
surrounds the bone.
(blood vessels carry
oxygen & nutrients to
bone)
• Compact Bone– thick layer beneath
periosteum.
– Dense (ivory texture)
– Not solid; filled with marrow
• Spongy Bone– Inside layer of spongy bone
– Not soft or spongy
– Strong (adds strength
w/out adding mass)
Structure continued…
• Haversian canals– Network of tubes that
carry blood vessels &
nerves.
– Supply bones with
blood.
Types of Bones
• Short
– carpals
• Long
– femur
• Irregular
– sphenoid
• Flat
– skull
Factors Affecting Bone Growth
• Mechanical Stress-weight lifting
• Nutrition
• Hormones
Body Positions
• Anatomical Position- arms by side, thumbs
up, feet slightly apart.
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Superior/Inferior
Anterior/Posterior
Ventral/Dorsal
Proximal/Distal
Medial/Lateral
Cephalic/Caudal
Anatomical Planes
• Sagittal- separates
Right and Left
• Frontal- separates
Front and Back
• Transverseseparates Top and
Bottom
How do bones move?
• Bones move by using a system of levers
called JOINTS.
• Joints– Where two bones meet
– Permit movement
– Hold bones in place
Joints
• Immoveable Joints– Fixed, allow no movement
– skull
• Slightly Moveable Joints– Small amount of mov’t
– Tibia, fibula, and vertebral column
• Freely Moveable Joints– Most joints, ends of bones covered with cartilage
– Synovial fluid-thin lubricant over joint
– Small pockets of synovial fluid (BURSAE)
Freely Moveable Joints
• Ball and socket- permits circular mov’t:
widest range of motion.
– (shoulder and hip)
• Hinge-back and forth mov’t
– (Elbow and knee)
• Pivot- allow rotation around a fixed point
– (atlas and axis) and (radius and ulna)
More Freely Moveable Joints
• Gliding-Sliding of one bone over another
– (Wrist, ankles, clavicles)
• Saddle-permit movement at 2 planes
– (Thumb)
• Ellipsoid- hinge type mov’t in 2 directions
– Fingers to palms and toes with soles.
Muscles
• Muscles make up ½ of the body’s weight.
Mrs. Hinzman in College
Three types of Muscles
• Skeletal- voluntary
– Attaches to bone
• Smooth- involuntary
– Alimentary canal, keeps eyes focused,
arteries
• Cardiac-involuntary
– Found only in the heart
Muscles
• Skeletal
– Striated, multinucleated
• Smooth
– Spindle shaped, single nucleus
• Cardiac
– Striated, single nucleus
Muscle Tone
• Muscles are kept in partial contracted
state by a steady flow of nerve impulses
from the spinal cord.
• If muscles lose nerve supply, what
happens?
– Shrinks, muscles lose about 2/3 bulk w/in
months
– Muscles can repair themselves
• Origin
– Muscle attachment on stable bone
• Insertion
– Muscle attaches to one or more moveable
bones.
Muscle STRENGTH
• Depends on muscle shape:
– Most powerful muscle is where?
• Spine-maintain posture and lifting
– Hand muscles-dexterity
– Eye (sphinctor) muscles- dialate, open and
close like a valve.
How Do Muscles Contract?
• Myosin- thick filaments
• Actin- thin filaments
• Cross Bridges- knoblike projections that
form in each myosin filament when actin
and myosin come together.
Sliding Filament Theory
• 1. When muscles contract, CROSS BRIDGES
move pulling the ACTIN and MYOSIN passed
each other.
• 2. After CROSS BRIDGES move as far as it
can, they release ACTIN to its natural position.
• Muscle work against each other (antagonist)
• Flexing-makes angle small (biceps)
• Extending-makes the angle bigger (triceps)
The Return of ATP
• ATP
– Gives us energy (how do we get ATP in our
bodies?)
– Aerobic process (required oxygen)-cellular
respiration
– Anaerobic process (no oxygen needed)fermentation (glycolysis)
– ATP makes and breaks contractions of actin
and myosin. (enzyme, acetylcholinesterase,
terminates a muscle contraction)
Questions???
• Do muscles push, pull, or do both?
• What would take longer to heal?
– Muscle, tendon, or ligament. Why?
Anterior
Temporalis
Deltoid
Pectoralis major/minor
Biceps
Sternocleidomastoid
Frontalis
Obicularis occuli/ oris
Quadriceps
Sartoris
Masseter
Gracilis
Obliques
Anterior Posterior
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Occipitalis
Trapezius
Hamstring
Latissimus Dorsi
Gastrocnemius
Triceps
Gluteus maximus
Gluteus medius
Integument (SKIN) System
• Skin is the largest organ in the body
• Self repairing
• How does skin repair itself? What
process occurs?
• What pigment determines the color of
skin?
Functions
• Protect body from injury or infection
• Helps regulate body temperature
– How?
• Removes waste
– How?
• Protects from UV rays
– How?
EPIDERMIS
– Outer most layer of skin, NO BLOOD
VESSELS, but has NERVES
– Cells undergo rapid division (MITOSIS)
– As new cells are produced, old cell are
pushed to surface become Keratin
– Keratin is tough fibrous protein that forms
hair, nails, and calluses
– Keratin waterproofs our skin
– New outer layer of skin is renewed every
14-28 days
DERMIS
• Inner most layer under the epidermis
• Contains blood vessels and nerves,
sense organs, smooth muscle, and hair
follicles
Hot or Cold?
• What does our body do to conserve
heat?
– Blood vessels constrict to limit the heat
lost…keeps us warmer
• What does our body do to cool down?
– Blood vessels open up, increases heat
loss
Glands in Dermis
• 1. Sweat gland– Produces sweat (salt and water)
– Nerve impulses stimulate when body temp.
rises
• 2. Sebaceous gland– Produces oily secretion called SEBUM
– Keeps skin flexible and waterproof
Hypodermis
• Layer beneath the dermis
• Composed mostly of fat
– Insulates the body
– Protects
– Energy storage