CLASSIFICATION OF BONES

BONES
The bones are the hard structure ,Which form the rigid framework the body.
Bone is a highly vascular mineralized connective tissue consisting of cell and dense intercellular organic matrix impregnated with organic salts. The organic material mainly consist of collagen fibers and form one third of the bone.
The inorganic material mainly consist of calcium phosphate and traces of other salts. It provides hardness and rigidity to the bone and makes it radiopaque in x-ray film.
FUNCTION

 Bone give shape and support to the body ,and resist any forms of stress.
 These provide surface for the attachment of muscle ,tendons,ligaments.
 These serve as levers for muscular actions.
 Bone marrow manufactures blood cells.
 Bone store 97%of the body calcium and phosphorus.
 Bone marrow contains reticuloendothelial cells which are phagocytic in nature and take part in immune responses of the body.
 The skull ,vertebral column and thoracic cage protect brain , spinal cord and thoracic and some abdominal viscera ,respectively.
 some bones around the nose contain large cavities filled with air (paranasal air sinuses which affect the timber of the voice).

CLASSIFICATION OF THE BONE

According to shape
According to the structure
According to the development

CLASSIFICATION ACCORDING TO THE SHAPE

Depending on the size and shape. the bone are classified into 7 type.
• Long Bones
• Short Bones
• Flat Bones
• Irregular Bones
• Pneumatic Bones
• Sesamoid Bones
• Accessory Bones

Long bones

Long bone are those in which length exceeds the breadth and thickness.
The long bone are two types.
 Typical long bones
 Miniature/short long bone

Short bones

Short bones are small in size and usually cuboidal in shape , presenting six surfaces. These bones are found in wrist (carpal bone ) and foot (tarsal bone).

Flat bones

Flat bone are flat and shallow plate-like bone.
They form boundaries of certain body cavities. the example of the flat bone frontal, parietal ,occipital ,scapula, ribs, sternum.

Irregular bones

Irregular bone are highly irregular shape ,hip bone vertebrae bone forming base of skull.

Pneumatic bones

Pneumatic bone are a variety of irregular bone which contain air filled cavity. These bones are mainly located around the nasal cavity.
Example maxilla ,frontal ,sphenoid and ethmoid bones.

Sesamoid bones

These are bony nodules found embedded in the tendons or joint capsules.they have no periosteum and ossify after birth. Ex. Patella.

Accessory bones

These bones are not always present. These may occur as ununited epiphysis developed from extra centres of ossification. Ex. Sutural or wormain bones.

CLASSIFICATION ACCORDING TO THE STRUCTURE

Microscopically the architecture of bone may be compact or cancellous.
Compact bone Compact bone is dense in texture like ivory ,but is extremely porous. It is best developed in the cortex of the long bone.
Cancellous bone The cancellous bone is a mesh work of bony spicules.it consist of interconnecting road and plates of bone called trabeculae.

CLASSIFICATION ACCORDING TO THE DEVELOPMENT

According to the process of the bone development. The bones are three type.
Membranous bones are developed by membranous ossification.
Cartilaginous bone are developed by endochondral ossification.
Membrano-cartilaginous bone developed by both membranous and endochondral ossification.

Parts of growing young long bone
 Epiphysis
 Diaphysis
 Metaphysis
 Epiphysis plate

Epiphysis these are ends of long bones which ossify from secondary centers.
Diaphysis It is the elongated part of bone between the metaphysis. It develops from primary ossification center.
Metaphysis the end of diaphysis toward the epiphyseal cartilage is called metaphysis.
Epiphysis plate Epiphysial plate separates epiphysis from metaphysis. Proliferation of the cells in this cartilaginous plate is responsible for lengthwise growth of a long bone.

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BONES IN HUMAN BODY

human skeleton is made up of 206 bones, here is a list of all bones which is present in human body.


Divided into two divisions.

Axial skeleton = 80 bones
Appendicular skeleton = 126 bones

1. AXIAL SKELETON

Skull = 28 bones

Cranium 8
Face 14
Auditory Ossicles 6

Hyoid = 1 bone

Vertebral column 33

Cervical -7

Thoracic 12

Lumbar 5

Sacrum 5

Coccyx 4

Sternum 1
Ribs 24

APPENDICULAR SKELETON

Pectoral girdles
Clavicle 2
Scapula 2

Upper extremities 30

Humerus 2
Ulna 2
Radius 2
Carpals 16
Metacarpals 10
Phalanges 28
Pelvic girdles
Pelvic or hip bone 2

Lower extremities 30

Femur 2
Fibula 2
Tibia 2
Patella 2
Tarsals 14
Metatarsals 10
Phalanges 28

ENDOCRINOLOGY

ENDOCRINOLOGY in short and if we get more information then we’ll update this post.

1) ADRENAL GLAND

HORMONE

  1. Adrenaline hormone
  2. Cortisol hormone
  3. Steroid hormone

Adrenaline –

             Action of the adrenalin include increasing the heart rate ,increasing blood pressure , expending the air passage of the lunge entering of the pupil in the eye.

CORTISOL

         Increases the gluconeogenesis in the liver.

Inhibitory effect on insulin which stop transport of glucose into the cells

Cortisol has diurnal variation.

No diurnal change In cushings syndrome.

STEROID HORMONES-

                   Steroid hormones play an important role in    –

Carbohydrate regulation (glucocorticoids)

Mineral balance (mineralocorticoide)

Reproductive function (gonadal steroids)

Steroid play a important role in inflammatory responses stress responses bone metabolism, cardiovascular fitness, behavior

2) THYMUS GLAND

A pink gland with two lobes located in the thoracic cavity posterior to the sternum.

It is large during the child hood and puberty but shrinks during adulthood.

FUNCTION

         Its primary function is to stimulate the production of T Cells which are an important part of the immune system.

Thymosin also assists in the development of B Cells to plasma cell to produce antibodies.

 Over production of thymosin- Lymphocytosis

3) PANCREAS

HORMONE     Insulin 

FUNCTION-

           Insulin is the only hormone that reduce blood glucose levels and it does this by activating the glucose transport mechanism and glucose utilizing metabolic pathway in different tissues of the body.

    GONADS

4) Testes

Hormone -androgen (testosterone)

Function

  1. Growth development and maintenance of male reproductive organs.
  2. Sexual differentiation and secondary sexual characteristics.
  3. Spermatogenesis
  4. Male pattern of aggressive behavior.
  5. pubertal transformation.
  6. Enlargement of testes ,penis and scrotum.
  7. Pubic and axillary hair.
  8. Bone growth
  9. RBC mass increase
  10. Skeletal muscle mass increase
  11. Larynx enlarges -deeping increase
  12. Development of beard.

5) Ovaries-

Hormone – Estrogens  and progesterone

Function

  1. Maturation growth and development of the reproductive organs
  2. Stimulation of normal physiological process of the tubular reproductive tract.
  3. Growth of the uterine tube
  4. Development of the endometrial lining of the uterus
  5. Increase the vascularity of the uterus
  6. Induction of the behavioral estrus
  7. Dilation of the cervix liquefaction of mucous plug.
  8. Under the influence of the estrogens the uterus is less susceptible to infection.

6) THYROID GLAND

Function of thyroid gland-

  1. Role in growth
  2. It has role in development
  3. It stimulate heart rate and contraction.
  4. Stimulate synthesis of proteins and carbohydrates
  5. It encreases vit. Requirements.

Function of thyroid hormone

  1. Maturation of bone
  2. Maturation of skeletal system
  3. Maturation of nerves in CNS
  4. Regulation of growth hormone
  5. Regulation of body temperature
  6. Generation of heat
  7. Metabolic function
  8. It  influence mood and behaviour

Disorders of thyroid gland – Hypothyroidism             

PARATHYROID HORMONE

Hormone  Calcitonin

Function of PTH

             Bone  Parathyroid hormone stimulates the release of calcium from large calcium stores in the bone into the bloodstream.

This increases bone destruction and decreases the formation of new bone.

Kidney Pth reduces loss of calcium in urine.

Pth stimulate the production of active vitamin D in the kidney.

Intestine  pth indirectly increases calcium absorption from food in the intestine via its effects on vitamin D metabolism.

7) PITUITARY GLAND

Posterior pituitary

Hormone     ADH

Function        Stimulate water reabsorption by kidney.

Hormone   Oxytocine

Function   Stimulate uterine muscle contraction release of milk by mammary gland.

Anterior pituitary

Hormone   TSH

Function     Stimulate thyroid gland.

Hormone    ACTH

Function      Stimulate adrenal cortex.

Hormone    PRL

Function      Milk production

Hormone   GH

Function      Cell division , protein synthesis ,and bone growth.

Hormone   MSH

Function Unknown function in humans regulates skin color in lower vertebrates.

TO BE CONTINUE-

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