MISS CARMEN MONANA APARRI

SKELETAL SYSTEMGROUP 1 NASC 1:30 PM TO 2:30 PM

Felecio, Irene Joyce Godinez, Diane Rañin, Manilac Melissa Regencia, Mercy Dale

Ybarita, Julius

<February 1, 2010>

[This document entails the important highlights of the Skeletal System (our report). This is the summary of the said topic.]

SKELETAL SYSTEM

Skeletal System: FUNCTIONS

1. Gives support and shape to the body.2. Acts as a firm base for the attachment of muscles.3. Protects the delicate underlying organs such as the brain, lungs and heart from

injury.4. Produces red blood cells.5. Serves as storage of calcium.6. Facilitates movement.

TYPES OF SKELETON:

1. Exoskeleton - Located outside the body of the animal.

2. Endoskeleton - Located inside the body of the animal.

INVERTEBRATE SKELETON:1. Sponges - spicules or sponging fibers2. Mollusks - skeleton consists mainly of calcium carbonate3. Arthropods - exoskeletons made up of organic material containing chitin.

VERTEBRATE SKELETAL SYSTEM- Consists of bones and cartilages

GRISTLE is a cartilage which has a firm elastic matrix called CONDRIN secreted by small groups of rounded cells called CHONDRIOCYTES . It is covered by a thin fibrous tissue called PERICHONDRIUM.

BONE OR OSSEOUS TISSUE is found only in the skeleton of bony fishes and land vertebrates. It is covered by a connective tissue called PEREOSTEUM.

OSTEOCYTES is embedded in a matrix made up of calcium salts and collagen. The function of this is to regulate the amount of calcium that is deposited in, or removed from the bone matrix.

CALCIUM SALTS are calcium carbonate and calcium phosphate, which give bone the strength required to perform its supportive and protective functions.

TWO TYPES OF BONE TISSUE:

1. COMPACT BONE – It looks solid but it is precisely structured.2. SPONGY BONE – It looks like a sponge with its visible holes and cavities.

CLASSIFICATION OF BONES:

1. LONG BONES – bones of the arms, legs, hands and feet. The shaft of a long bone is the DIAPHYSIS , and the ends are called EPIPHYSIS.

a. DIAPHYSIS is made of compact bone and is hollow, forming a canal within the shaft. This marrow canal is lined with a connective tissue called ENDOSTEUM and contains YELLOW BONE MARROW, which is moistly adipose tissue.

b. EPIPHYSIS are made up of spongy bone covered by a thin layer of compact bone.

2. SHORT BONES – bones of the wrists and ankles.

3. FLAT BONES – the ribs, shoulder blades, hip bones and cranial bones.

4. IRREGULAR BONE – the vertebrae and facial bones.

DIVISION OF BONES:

1. AXIAL DIVISION - the bones and cartilages in the middle or axis of the body. a. Skull is made up of cranium, and jaw bones.b. Vertebral Column is made up of a series of vertebrae: cervical, thoracic,

lumbar, sacral and caudal.

c. Rib cage is composed of a series of flat bones which support the chest wall and keep it from collapsing as the diaphragm contracts.

TYPES OF RIBS:o True Ribs – ends are attached to the sternum by means of

costal cartilage (seven pairs in man).o False Ribs – attached indirectly by cartilage to the seventh rib

( 3 pairs in man).o Floating Ribs – have no attachment to the breastbone and

therefore have free ends ( 2 pairs in a man).d. Sternum or breastbone articulates with bones of the pectoral girdle and

serves for attachment of the ribs.

2. APPENDICULAR DIVISION – made of limbs and girdlesa. Forelimbs – bones of the arm

HUMERUS – upper arm RADIO-ULNA – lower arm CARPAL – wristbones (8) METACARPALS – palm (5 bones) PHALANGES – fingers (14 bones)

b. Hindlimb FIMUR – thigh bone TIBIO-FIBULA – shank TARSALS – ankle (7) METATARSALS – sole (5) PHALANGES – toes (14)

c. Girdles PECTORAL GIRDLE – clavicle, scapula or shoulder blade, and

coracoids. PELVIC GIRDLE – ilium, ischium and pubis

d. Joints are points of junction between two bones; they make movement possible.

TYPES OF JOINTS:o SYNARTHROSIS – immovable joints; bones are closely

packed together so that no movement is possible.o AMPHIARTHROSIS – slightly movable joint; permits movement

in one direction only.o DIARTHROSIS – freely movable joint; permits free

movement in several directions.

FACTORS THAT AFFECT BONE GROWTH AND MAINTENANCE:

1. Heredity - each person has a genetic potential for height, that is, maximum height, with genes inherited from both parents.

2. Nutrition - nutrients are the raw materials of which bones are made. - Calcium, Phosphorus and Protein- become part of the bone matrix itself.- Vitamin D is needed for the efficient absorption of calcium and phosphorus by the small intestine.- Vitamins A and C do not become part of the bone but are necessary for the process of bone matrix formation (ossification).

3. Hormones - Endocrine Glands produce hormones that stimulate specific effects in certain cells. These include: hormone, thyroxine, parathyroid hormone and insulin –which help regulate cell division, protein synthesis, calcium metabolism and energy production. - The sex hormones estrogen or testosterone help bring about the cessation of bone growth.

Growth Hormone ( anterior pituitary gland)- increases the rate of mitosis of chondriocytes and osteoblasts.

Thyroxine ( thyroid gland)- increases the rate of protein synthesis. Increases energy production from all food types.

Insulin ( pancreas)- increases energy production from glucose

Parathyroid hormone ( parathyroid gland)- increases the re absorption of calcium from bones to the blood (raises blood calcium level)- increases the absorption of calcium by the small intestine and kidneys (to the blood)

Calcitonin ( thyroid gland)- decreases the re absorption 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” - exercise means bearing weight, which is just what bones are specialized to do. This need not be strenuous; it can be as simple as walking everyday.

AGING AND SKELETAL SYSTEM: SIGNS

Bone tissue tends to lose more calcium. Bone matrix becomes thinner, the bones themselves more brittle and fractures

more likely to occur. Erosion of the articular cartilages of joints.

All of these can be prevented by preserving their bone matrix with exercise and diets which are high in calcium and Vitamin D.