Changes

Bone marrow is referred to as [[#Red marrow|red]] or [[#Yellow marrow|yellow]]. Red bone marrow is involved with haemostasis while yellow bone marrow is adipose tissue. Bone marrow occupies the cavities in [[Bones and Cartilage - Anatomy & Physiology#Types of Bone|long bones]] and spaces in [[Bones and Cartilage - Anatomy & Physiology#Types of Bone|spongy bones]].

Bone marrow is referred to as [[#Red marrow|red]] or [[#Yellow marrow|yellow]]. Red bone marrow is involved with haemostasis while yellow bone marrow is adipose tissue. Bone marrow occupies the cavities in [[Bones and Cartilage - Anatomy & Physiology#Types of Bone|long bones]] and spaces in [[Bones and Cartilage - Anatomy & Physiology#Types of Bone|spongy bones]].

==Development==

==Development==

<p>Haematopoietic stem cells migrate into bones during embryo development, a process called homing. The cells then associated closely with the connective tissues within the bone. </p>

<p>Pluripotential haematopoietic stem cells (PPSC) migrate into bones from the embryonic yolk sac and the foetal liver during development, a process called homing. The cells then associated closely with the connective tissues within the bone. The PPSCs continue to constantly divide in the bone marrow with one daughter cell remaining a pluripotential stem cell and the other daughter cells develops into a multipotential haematopoietic stem cells. The multipotential stem cells also constantly divide with some daughter cells remaining stem cells and the other daughter cells developing into blood cells ([[Haematopoiesis - Anatomy & Physiology|Haematopoiesis]]).</p>

 

==Red marrow==

==Red marrow==

<p>Red bone marrow consists of blood vessels, sinusoids and a note work of haematopoietic cells. Sinusoids and vascular components with an endothelial layer, basal lamina and an outer adventitial cell layer. The adventitia cells are also called reticular cells and these extend into the haematopoietic cells in sheets to provide structural support. They also produce reticular fibres and cytokines to help stimulate blood cell production. Histological sections show that the haematopoietic cells lie in cords. The cells in these cords form many different blood cell types but cells producing one cell type tend to be located in groups along the cords.</p>

<p>Red bone marrow consists of blood vessels, sinusoids and a note work of haematopoietic cells. Sinusoids and vascular components with an endothelial layer, basal lamina and an outer adventitial cell layer. The adventitia cells are also called reticular cells and these extend into the haematopoietic cells in sheets to provide structural support. They also produce reticular fibres and cytokines to help stimulate blood cell production. Histological sections show that the haematopoietic cells lie in cords. The cells in these cords form many different blood cell types but cells producing one cell type tend to be located in groups along the cords.</p>