How do white blood cells leave the blood stream?

Answer 1

Bone - surprising to many people - is vascular, which means it has a plentiful access to blood. So, since it has blood vessels running though it, especially the spongy bone at the ends of long bones, it is quite easy for the blood cells that form in red bone marrow to find their way into the blood stream.

Answer 2

Red blood cells are formed in the red bone marrow of bones. Stem cells in the red bone marrow called hemocytoblasts give rise to all of the formed elements in blood. If a hemocytoblast commits to becoming a cell called a proerythroblast, it will develop into a new red blood cell.

The formation of a red blood cell from hemocytoblast takes about 2 days. The body makes about two million red blood cells every second.

Blood is made up of both cellular and liquid components. If a sample of blood is spun in a centrifuge, the formed elements and fluid matrix of blood can be separated from each other. Blood consists of 45% red blood cells, less than 1% white blood cells and platelets, and 55% plasma.

I have MDS w/CML, Hematologists and Oncologists have explained this thoroughly and have read medical journals to learn as much as possible.

Addition: To answer your question more specifically; Bone marrow has a vascular compartment (The medial compartment located beneath the inguinal ligament for the passage to the femoral vessels and separated from the muscular lacuna-a cavity between muscle by the iliopectineal arch or artery) and an extravascular compartment (situated or occurring outside a vessel or the vessels) , hematopoiesis (the forming of new blood cells) takes place in the extravascular compartment (where cells are developing) blood cells, plasma cell, macrophages and fat cells. The vascular compartment is supplied by a nutrient artery which branches into central longitudinal arteries which send out radial branches that eventually open into sinuses (non nasal). These sinuses converge into a central vein that carries the blood out of the bone marrow into the general circulation.

Answer 3

They join the blood stream through the large gaps in discontinuous cappilarries.

Answer 4

the blood vessels dilate and become leaky, allowing proteins and wbcs to leave the bloodstream and migrate to the site of the injury

Answer 5

Through vessels in the bone.