SKELETAL SYSTEMSKELETAL SYSTEM

Functions:

1. Physical support and protection of the internal organs

2. Responsible for body movement together with muscles

3. Serves as firm base for muscle attachment

4. Storage of calcium

5. Forms blood cells (by red bone marrow)

Invertebrate Skeleton:

1.Sponges – spicules or sponging fibers

2. Mollusks – skeleton consists mainly of calcium carbonate

3. Arthropods – exoskeletons made up of organic materials containing chitin

Made up of:

CartilageCartilage

BoneBone

LigamentsLigaments

TendonsTendons

The skeletal system is made up of:

a. Cartilage – provides skeletal system with connection, support, flexibility and protection.

- covered by perichondrium

Cells – chondrocytes imbedded in matrix called chondrin

BONE

Composed of:

1. matrix of collagenous fibers

2. Calcium

3. cementing substance (composed of water and mucopolysaccharides; binds crystals to matrix)

4. Lacunae - one of the minute cavities in bone or cartilage occupied by the osteocytes

5. Canaliculi - a small channel found in ossified bone

Osteocytes – bone cells

Osteoblasts – bone-forming cells

Periosteum – outer covering of the bone (connective tissue)

Endosteum – covers the inner lining of the bone

MARROW: occupies cavities between trabeculae

) consists of a reticulum of connective tissue fibers that support blood vessels, nerve fibers, and adipose tissue (yellow marrow)

red marrow in some bones produces red blood cells (hemopoietic tissue) and some types of white blood cells

COMPACT BONE consists of lamellae of mineralized

collagenous bundles arranged concentrically around a haversian canal

osteon or haversian system consists of: haversian canal (w/ arteriole, venule, lymph vessel, nerve fibers) and surrounding lamellae

vessels in the canals continuous with those in bone marrow

Ex. Long bones

SPONGY BONE chancellors bone

consists of bony trabeculae and bone marrow

Trabeculae: assemblage of beams, bars and rods that form a rigid framework whichprovides maximum strength at areas of stress

composed of irregularly arranged lamellae without haversian systems

Kinds of Cartilage:

1. Hyaline cartilage – larynx, trachea, bronchi

2. Elastic cartilage – external ears, epiglottis

3. Fibrous cartilage – intervertebral discs, point of attachment of tendons and ligaments

Ligaments – connect bones to bones allowing movement between two or more bones.

Tendons – connect muscle to bone.

JOINTS

Refers to the articulation between cartilages or bones

Types:1. synarthroses – immovable joints2. diarthroses – freely movable joints

3. Amphiarthroses – slightly movable joints

Synarthroses – immovable joints; no joint cavity* Sutures – skull bones

* teeth in jaw bones

Diarthroses- has the joint cavity between the articulating surfaces of the 2 bones that forms the joint

1. ball-and-socket joints - free rotary movement; in hip and shoulder (hip, shoulder)

2.hinge joints- movement is limited to

1 plane; in elbow and knee

3. Pivotal or rotatory (atlas, axis)- are joints where bones can rotate around each other and are found in the articulation of the skull with the spinal cord 4. gliding joints - where bones can glide ; in wrist, ankles

3. Amphiarthroses – slightly movable joints

Two Divisions of Skeleton Axial Skeleton – skull, vertebral

column, pectoral bones (80 bones)

Appendicular Skeleton – appendages (126 bones)

Bones of the vertebral column: (26 bones)1. Cervical (neck) – 7 bones

2. Thoracic (chest) - 12 bones

3. Lumbar (lower back) – 5 bones

4. Sacral - 1 bone (made up of 5 fused vertebrae)

5. Coccyx (tail bone) – 1 bone (made up of 3 to 5 fused vertebrae)

Thoracic cage: (25 bones)

1. Sternum – 1 bone

2. Ribs – 24 bones

a. true ribs (14) – attach to the sternum

b. false ribs (6) – not directly attach to sternum but through costal cartilage fused

together and merged with rib # 7

c. floating ribs (4) – not attach to sternum; no costal cartilage

Thoracic vertebrae – bear long ribs, reaching the ventral side

12 - man

Lumbar vertebrae

Appendicular bones: arms and legs (126)

a. Forelimbs (arm) 30 x 2 = 60 bones* humerus – upper arm (1)* radio-ulna – lower arm (2)* carpal – wrist (8)* metacarpals – palm (5)* phalanges – fingers (14)

b. Hindlimbs (legs) 30 x 2 = 60 bones

* femur – thigh (1)* tibia-fibula - lower leg

(2)* patella - 1* tarsals – ankle (7)* metatarsals – sole (5)* phalanges – toes (14)

c. Girdles:

1. Pectoral girdle (4 bones)* clavicle or collar

bone* scapula or

shoulder blade

2. Pelvic girdle (2)

Kinds of Bones According to Shape:

1. long bones – in extremities

2. short bones – wrist bones

3. flat bones – shoulder blades

4. irregular bones – vertebral column

Factors that affect bone growth an maintenance:

1. Heredity2. Nutrition - Calcium, phosphorous and protein –

part of the bone matrix- Vit. D – needed for calcium and phosphorous ab sorption by the cell lining the s.i.- Vit. A and C – needed for ossification of bone matrix

3. Hormones – endocrine glands produce hormones that stimulate specific effects in certain cells.

growth hormone Thyroxine Parathyroid hormone Insulin

Help regulate cell division, protein sysnthesis, calcium metabolism, and energy production

The sex hormones estrogen or testosterone help bring about the cessation of bone growth.

Hormones Function

Growth hormone (anterior pituitary gland) Increases the rate of mitosis of chondriocytes and osteoblasts

Thyroxine (thyroid gland) Increases the rate of protein synthesisIncreases energy production from all food types

Insulin (pancreas) Increases energy production from glucose

Parathyroid hormone (parathyroid gland) Increases the reabsorption of calcium from bones to the blood (raises blood calcium level)Increase the absorption of calcium by the small intestine and kidneys (to the blood)

Calcitonin (thyroid gland) Decreases the reabsorption of calcium from bones (lowers blood calcium level)

Estrogen (ovaries) Promotes closure of the epiphyses of the long bones (growth stops)

Testosterone (testes) Helps retain calcium in bones to maintain a strong bone matrix

4. Exercise or stress

Without this stress, bones will lose calcium faster than it is replaced.

Skeleton of a frog: web-footed amphibian which lives near lakes and ponds. Moves by swimming and jumping.Maxillary: bony part of the jaw.Orbital cavity: skull cavity that contains the eye.Quadratojugal: cheek bone.Prootic: bones forming the auditory region.Phalange: each of the small bones forming the fingers.Occipital lateral: occipital lateral bone.Carpus: each of the bones forming the wrist.Metacarpus: each of the bones forming the part of the hand between the fingers and the wrist.Urostyle: adaptation of one or several vertebrae, stretching the hindquarters.Ilium: projecting hip bone.Ischium: one of three bones forming the ilium.Calcaneum: projecting heel bone.Talus: bone jointed with the leg bones.Phalanges: each of the bones forming the toes.Metatarsus: each of the bones forming the part of the foot between the toes and the heel.Tarsus: each of the bones forming the heel.Femur: thigh bone.Tibiofibula: leg bone.Sacral vertebra: vertebra of the sacrum.Vertebra: each of the bones forming the spinal column.Humerus: arm bone.Radio-ulna: forearm bone.Scapular: shoulder bone.Pterygoid: one of the bones of the palate, forming the root of the mouth.Skull: bony case of the brain.

Pectoral Girdle

Pelvic Girdle

acetabulumacetabulumPubic symphysis

ischium

The End!The End!

Composition of Bone Tissue1. Inorganic matter – about 77 %

* calcium phosphate* calcium carbonate

* water * calcium fluoride * sodium chloride

2. Organic matter – cells, blood vessels, gelatinous substance – about 33 %

B. According to composition:

1. Decalcified bone – contains more organic substances and less inorganic substances

2. Calcified bone – contains more inorganic substances and less organic

Disorders of the Skeletal System

1. Fractures – broken bonesTypes:a. Complete – broken

bone is separated into 2 partsb. Incomplete – broken bone is not separated into 2 partsc. Simple – part of the broken bone does not pierce the skind. Compound – part of the broken bone pierces and protrudes through the skine. Greenstick – an incomplete break on one side of the bone with the other side bowedf. Comminuted – bone is broken into several fragmentsg. impacted fracture - one in which one fragment is firmly driven into the other.

2. Osteoporosis – weakening of the bones due to the removal of calcium salts. This is a common problem in older persons due to inactivity and a decrease in hormone production. It is more common in postmenopausal women because

of the lack of estrogen.

3. Rickets – a disease of the children that is characterized by softening of bone due to deficiency of calcium salts in the bones and vitamin D.

4. Osteosarcoma – malignant tumor of the bones.

Disorders of Joints1. Arthritis – general term for the different diseases of

joints characterized by inflammation, swelling (edema), and pain.

Types:a. Rheumatoid arthritis – most painful and crippling

type. The synovial membrane thickens, synovial fluid accumulates causing swelling of the joints. The joint is invaded by fibrous connective tissue that ultimately ossifies making the joint immovable.

b. Osteoarthritis – most common type – a degenerative disease that results from aging and wear. The articular cartilages gradually disintegrate which cause pain and restricts movement.

c. Gouty arthritis – results from a metabolic disorder in which an abnormal amount of uric acid is retained in the blood and sodium urate crystals are deposited in the joints which causes swelling, tissue deterioration, and pain.

2. Bursitis – inflammation of the bursa due to excessive use and injury.

3. Dislocation – displacement of bones forming a joint. Pain, swelling, and reduced movement are associated with a dislocation.

4. Herniated disk – a condition in which an intervertebral disk protrudes beyond the edge of a vertebra. It is caused by excessive pressure on the vertebral column, which compresses a disk and causes it to bulge outward which put pressure on a spinal nerve and cause pain.

5. Spinal curvatures – usually congenital disordersTypes:a. Kyphosis – excessive thoracic curvature of the vertebral column which produces a humpback condition.

b. Lordosis – excessive lumbar curvature of the vertebral column which produces a swayback condition.

c. Scoliosis – abnormal lateral curvature of the vertebral column.

6. Sprains – result from tearing or excessive stretching of the ligaments and tendons at a joint without dislocation.

QUESTIONS:

1.Give the differences between compact and spongy bone, and state where each type is found in the body.

______________________________

2. Name the bones that make up the rib cage, and describe two functions of the rib cage __________________

3. Give 1 specific example (bones) for each of the following types of joints:

a. hinge _______________________________b. symphysis ___________________________c. pivot _______________________________d. suture ______________________________e. ball and socket _______________________