Skeletal and muscular Skeletal and muscular systemsystem

Concept Concept mappingmapping

What is skeleton?What is skeleton?

Skeleton: collection of bones that holds our body up.

Baby has 305 bones and an adult has 206 bones

Why ? because as we grown some of our

bones join together to form one bone

Types of skeletonsTypes of skeletonsExo-skeleton: animals that

have shells

Endo-skeleton: hard structure inside the animal.

Hydrostatic skeleton: Fluid held inside the

body

No skeleton

Five functions of our Five functions of our skeletonsskeletons

1. Protect the vital organs

2. Give us shape

3. Allow us to move because our muscles are attached to our bones

4. Storage of nutrients such as calcium and silicon

5. Formation of blood cells

Human Human skeletonsskeletons

Clavicle

Cranium

MandibleScapula

Rib

VertebraInnominateSacrum

Sternum

Humerus

Radius

Ulna

Patella

Tibia

Fibula

Tarsals

CarpalsMeta carpalsFalangsFemur

Metatarsals

X-raysX-raysThe tool used to examine bonesThe tool used to examine bones

6-9

Components of Skeletal SystemBoneCartilage: three types

◦Hyaline◦Fibro cartilage◦Elastic

Bone ShapesBone ShapesLong / Pipe

◦ Ex. Upper and lower limbs

Short◦ Ex. Carpals and

tarsals, bones in wrist and ankles

Flat◦ Ex. Ribs, sternum,

skull, scapulae Irregular

◦ Ex. Vertebrae, facial

6-10

Long Bone Long Bone Structure Structure

Long bone surrounds by tissues called periosteum

Under periosteum is tissues called compact bone/ hard bone which contains bone cells, blood vessels, Ca, Phosphorus, and elastic fibers

Ends of long bone covered by tissues called cartilage

What is bone marrow?What is bone marrow?

Fatty tissue, located in the cavities in the center of long bones or spaces of spongy bones

Red marrow produce erythrocytes, most of leucocytes and platelets

Yellow marrow produce some leucocytes. It colors is due to the much higher number of fat cells

No diaphyses and not elongated

Compact BoneCompact Bone

6-14

Central or Haversian canals: parallel to long axis

Perforating or Volkmann’s canal: perpendicular to long axis. Both perforating and central canals contain blood vessels. Direct flow of nutrients from vessels through cell processes of osteoblasts and from one cell to the next.

Lamellae: concentric, circumferential, interstitial

Osteon or Haversian system: central canal, contents, associated concentric lamellae and osteocytes

Osteocytes. Mature bone cells. Surrounded by matrix

Lacunae: spaces occupied by osteocyte cell body

Canaliculi: canals occupied by osteocyte cell processes

OsteocytesOsteocytes

6-16

Bone HistologyBone HistologyBone matrix. Like reinforced concrete. Rebar is

collagen fibers, cement is hydroxyapetite◦ Organic: collagen and proteoglycans◦ Inorganic: hydroxyapetite. CaPO4 crystals

Bone cells (see following slides for particulars)◦ Osteoblasts Formation of bone through

ossification or osteogenesis.

◦ Osteocytes ◦ Osteoclasts Resorption of bone

◦ Stem cells or osteochondral progenitor cellsWoven bone: collagen fibers randomly orientedLamellar bone: mature bone in sheetsCancellous bone: trabeculaeCompact bone: dense

6-17

Bone Bone MatrixMatrix

If mineral removed, bone is too bendable If collagen removed, bone is too brittleExtracellular matrix contains mineralization by

crystal which contains Ca, Phosphate, and Carbonate (Hydroxyapetite)

6-18

Cancellous (Spongy) BoneCancellous (Spongy) Bone

Trabeculae: interconnecting rods or plates of bone. Like scaffolding. ◦ Spaces filled with marrow. ◦ Covered with endosteum.◦ Oriented along stress lines

6-19

Bone Development Bone Development

cartilages (before born)

Osteoblast (bone forming cells contains Ca and P)

Osteocytes (bone cells)

Osteoclast (destroy bone tissues and release Ca and P in blood circulation)

Chicken Bone ExperimentChicken Bone Experiment

Aim To see what happens to bones when we leave them in acid (vinegar) and water.

This experiment can be set up and left in your classroom for the next four days after which the students will see the results. Students mission is to write up what they think will happen to the chicken bones in each bottle and why?

Materials and Equipment Clean chicken bones ( thigh bones)Two glass jars with lids per groupWaterWhite vinegarPaper towels

PROCEDUREPlace some chicken bones in each jar.Label one jar with your groups name, date and ‘water’

– add the bones and waterLabel the second jar with your groups name, date and

‘vinegar’ – add bones and vinegarLeave the jars for about 3 weeks after which you can

remove and dry the bones on some paper towelsObserve the difference in the two sets of bones

DISCUSSIONWhat has happened to each set of bones and why?

6-23

Factors Affecting Bone GrowthSize and shape of a bone determined genetically

but can be modified and influenced by nutrition and hormones

Nutrition◦ Lack of calcium, protein and other nutrients during growth

and development can cause bones to be small◦ Vitamin D

Necessary for absorption of calcium from intestines Can be eaten or manufactured in the body Rickets: lack of vitamin D during childhood Osteomalacia: lack of vitamin D during adulthood leading

to softening of bones◦ Vitamin C

Necessary for collagen synthesis by osteoblasts Scurvy: deficiency of vitamin C Lack of vitamin C also causes wounds not to heal, teeth to

fall out

6-24

Factors Affecting Bone Growth, cont.Hormones

◦ Growth hormone from anterior pituitary. Stimulates interstitial cartilage growth and appositional bone growth

◦ Thyroid hormone required for growth of all tissues

◦ Sex hormones such as estrogen and testosterone Cause growth at puberty, but also cause closure

of the epiphyseal plates and the cessation of growth

6-25

Bone Fractures

Open (compound)- bone break with open wound. Bone may be sticking out of wound.

Closed (simple)- Skin not perforated.

Incomplete- doesn’t extend across the bone. Complete- does

Comminuted fractures: complete with break into more than two pieces

Joints are the point were bones meet. There are two groups, movable and immovable joints

Ball-and-socket joints- formed when a rounded head of one bone fits into the rounded cavity of an jointed bone.

Hinge joints-would include elbow, knee, ankle, and fingers. Allows extension and retraction of apendage

Sadle joints- A saddle joint allows movement back and forth and up and down, bot does not allow for rotation like a ball and socket joint.

JointsJoints

Gliding joints- In a gliding or plane joint bones slide past each other. Midcarpal and midtarsal joints are gliding joints.

Pivot joints- allow limited rotation or turning of the head

Ellipsoidal joints- bone in wrist, and a oval shaped part that fits in a curved space, the joints slide over each other

Functions of the Muscular System Involuntary

Some involuntary functions of the muscular system are muscles to help you breathe, make your heart beat,

and help move food through the digestive system. Voluntary

Some voluntary functions of the muscular system are like playing piano, running, playing video games, and

throwing a ball.

MusclesMusclesAn organ that can contract to become shorter

MusclesMusclesAn organ that can contract to become shorter

CardiaCardiac c MuscleMuscle

•One, centrally located nucleus•Presence of striations•Short, branched cells•“involuntary”•Myogenic (contraction originates within the muscle cell)

•Does not fatigue

Skeletal Skeletal MuscleMuscle

Many, peripherally located nuclei (develops from many myoblasts)

Presence of striations Long (up to 30 cm), thin cells “voluntary” Neurogenic (contraction is initiated my motor

neuron input) Can fatigue

Smooth MuscleSmooth Muscle

• One, centrally located nucleus• No striations• Short, tapered cells• “involuntary”• Myogenic with some neurogenic modulation• Does not fatigue

Synergists = muscles that work together to produce certain movements (ex. Multiple arm muscles are needed for flexion of the antibrachium)

Antagonists = muscle(s) that work(s) to oppose certain actions = moves the structure in the opposite direction (ex. Triceps brachii is an antagonist to the biceps brachii and causes extension of the antibrachium)

Muscles consist of a –◦Belly = the region with the muscle fibers

◦Tendon = connective tissue at the ends of the muscle that is continuous with the muscle and the connective tissue layer of the bone to which the muscle attaches

◦Fascia = connective tissue layer that surrounds the muscle

FracturesJoints

Dislocation- is when the ligaments attached to the bone are torn or out of place

Torn cartilage- is a sharp blow or twisting of the joint

Arthritis- inflammation of the joint and is a result of natural wear and tear

Fasiculus = a bundle of muscle fibers, many per muscle

Muscle Fiber = a single muscle cell

Epimysium (fascia) = connective tissue layer that holds many fasiculi together, with the associated nerves, arteries and veins, to form a muscle (an organ)

Perimysium = connective tissue layer that surrounds and produces a fasiculus

Endomysium = connective layer surrounding a single muscle fiber

Microscopic anatomy of muscle cells

Sarcomere = smallest contractile unit in a muscle fiber; extends from Z-line to Z-line

A (anisotrophic band) band = “without change band” = at low magnification it looks the same regardless of the contractile state of the muscle; contains thick myofilaments overlapped with thin myofilaments

I (isotrophic band) band = “with change band” = density changes at low magnification depending upon the contractile state of the muscle; at rest, contains only thin myofilaments

Z-lines = dense regions at the ends of sarcomeres, serve as sites of thin filament attachment

H-zone = region in the middle of the A-zone that at rest contains only thick filaments

Muscular ContractionImpulse from nervous system

Sliding Filament Theory of Muscular Contraction

Muscle contraction occurs when thick (myosin) and thin (actin) myofilaments are allowed to interact; thin filaments “slide” along thick filaments to the center of the sarcomere, thus shortening the contractile unit

2. Sartorius3. Deltoid4. Sternocleidomastoid5. Tibialis 6. Hamstring group7. Rectus Abdominus8. Triceps 9. Biceps 10. Extensor Group

1. Gastrocnemius