What is bone marrow?Its structure with various types

Bone marrow.

In long bones such as limb bones a cavity called bone marrow cavity is present inner to the endosteum.the bone marrow cavity is filled with soft and semisolid fatty neurovascular tissue termed as bone marrow.in fact bone marrow is a special kind of tissue which is called myelogenous or myeloid tissue.

Types of bone marrow.

It is of two types (a) red bone marrow.it is red due to abundant blood vessels.it is present in the spongy parts of the bones .it produces red blood corpuscles,white blood corpuscles and platelets.(b)yellow bone marrow.it is present in the shafts of long bones .it is yellow in colour and has much fatty tissue.it produces blood corpuscles in emergency,at the time of excessive loss of blood;when it changes into red bone marrow.
                                                           
What is bone marrow?its structure with various types
Picture of bone marrow
During foetal life and at birth there is red bone marrow throughout the skeleton.after about the fifth year the red bone marrow is gradually replaced in the long bones by yellow bone marrow.By 20 to 25 years the red bone marrow persists only in the vertebrae,sternum,ribs,clavicles,scapulae,pelvis,cranial bones and in the proximal ends of femora and humeri.In old age the bone marrow of the cranial bones undergo degeneration and is then called gelatinous marrow.
if you want to know about bone marrow so it is obvious that you will also want to know about Endosteum.So we are going to discuss about the endosteum in the below..
Endosteum.It is present in the outer to the bone narrow cavity like the periosteum,it comprises white fibrous tissue and osteoblasts.The long bone thus grow in thickness from both sides thats amazing yeah! this type of growth is called the bidirectional growth.
So that is for today we are going to discuss about a new topic in the next session.

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