Bone Marrow Structure and Function

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Questions and Answers

What are the two types of bone marrow found in the body?

Active marrow and inactive marrow

Red marrow and white marrow

Red marrow and yellow marrow (correct)

Red marrow and blue marrow

What are hemopoietic cords primarily composed of?

Adipose cells and fat deposits

Developing blood cells and macrophages (correct)

Fibroblasts and endothelial cells

Platelets and reticular fibers

What is the main function of megakaryocytes?

Produce red blood cells

Form fat storage cells

Produce white blood cells

Produce platelets (correct)

Which component of the bone marrow forms an extensive, communicating network?

Sinusoids Signup and view all the answers

How are the nests of erythrocytes organized within the bone marrow?

Erythrocyte nests contain a macrophage and are found near the sinusoidal wall Signup and view all the answers

What characteristic is associated with the nucleus of megakaryocytes?

It is polyploid with irregularly lobulated structure Signup and view all the answers

Which statement about yellow marrow is accurate?

It is filled with adipocytes and excludes hemopoietic cells Signup and view all the answers

What type of cells are primarily found in the stroma of the bone marrow?

Adventitial reticular cells and macrophages Signup and view all the answers

What primarily gives red bone marrow its color?

High content of hemoglobin in red blood cells Signup and view all the answers

Which statement accurately describes the location of yellow bone marrow in adults?

Most of the marrow in adults Signup and view all the answers

What is the primary function of red bone marrow?

Production of blood cells Signup and view all the answers

Which of the following can yellow bone marrow do in times of need?

Change into active red bone marrow type Signup and view all the answers

Which blood cells are generally produced by red bone marrow?

Granulocytes, monocytes, and platelets Signup and view all the answers

What role do sinusoidal macrophages play in red bone marrow?

Destruction of old RBCs Signup and view all the answers

The primary difference in function between yellow and red bone marrow is that yellow bone marrow is mainly for:

Storage of fats Signup and view all the answers

In the context of blood cell production, erythropoiesis specifically refers to which process?

Development of red blood cells Signup and view all the answers

What is the primary function of red bone marrow in adults?

Production of erythrocytes, leukocytes, and thrombocytes Signup and view all the answers

At what stage of development does bone marrow become the main site of hemopoiesis?

From the 2nd trimester of fetal life Signup and view all the answers

Which type of bone marrow is mainly responsible for fat storage?

Yellow bone marrow Signup and view all the answers

Where does hematopoiesis occur in normal adult life?

Mainly in flat bones and proximal ends of long bones Signup and view all the answers

What characterizes the yolk sac phase of hemopoiesis?

Presence of blood islands Signup and view all the answers

Which hematopoietic phase is primarily responsible for the formation of erythroid cells?

Hepatic phase Signup and view all the answers

As adults age, what happens to hemopoiesis in the bone marrow?

It gradually recedes Signup and view all the answers

What type of cell is primarily produced in the yellow bone marrow?

Fat cells Signup and view all the answers

Study Notes

Bone Marrow

Bone marrow is where hematopoiesis occurs in adults.
Bone marrow is located in the medullary cavity of long bones and spaces of spongy bone.
There are 2 types of bone marrow in the body: red and yellow.
Red bone marrow is highly vascular and hemopoietically active.
Yellow bone marrow is rich in fat and filled with adipocytes.

Stroma

Stroma consists of loose reticular connective tissue that supports hematopoietic cells.
The stroma of the bone marrow is composed of modified fibroblasts and reticular fibers.
Modified fibroblasts (adventitial reticular cells) produce reticular fibers.
Reticular fibers support hematopoietic cells and macrophages
Reticular cells have cell adhesion molecules on their surface.

Parenchyma

The parenchyma of bone marrow is composed of sinusoids and hemopoietic cords.
Sinusoids are thin-walled vessels.
Sinusoids form an extensive network.
The sinusoidal wall is composed of fenestrated endothelial cells, a discontinuous basal lamina and an outer adventitial cell layer.
Hemopoietic cords are islands of cells that are well organized.
Hemopoietic cords contain megakaryocytes, developing blood cells, macrophages, mast cells and some adipose cells.
Erythrocyte nests contain a macrophage and are located near the sinusoidal wall.
Megakaryocytes are located adjacent to the sinusoidal wall.
Granulocyte nests are located farther from the sinusoidal wall.

Megakaryocyte

Megakaryocytes are giant cells that produce platelets.
Megakaryocytes are up to 150 um in diameter.
Megakaryocytes contain a large, ovoid or kidney shaped nucleus that is irregularly lobulated with coarse chromatin.
Megakaryocyte cytoplasm is basophilic and contains numerous mitochondria, a well-developed rough ER, and an extensive Golgi apparatus.
From the Golgi apparatus arise the conspicuous specific granules of platelets.
Megakaryocytes are typically found near sinusoidal capillaries.

Types of Bone Marrow

Red bone marrow is red because of its high hemoglobin content.
Yellow bone marrow is yellow because of its high fat content.
In a fetus, most of the marrow is red.
In adults, most of the marrow is yellow.
Red bone marrow is found in the epiphyses of long bones, vertebrae, sternum and ribs.
Yellow bone marrow is mostly found in long bones in adults.
The function of red bone marrow is to produce blood cells and destroy old RBCs.
Yellow bone marrow stores fats and can change to active red bone marrow in times of need.

Function of Bone Marrow

Bone marrow produces RBCs, granulocytes, monocytes and platelets which are released into the circulation
Lymphocytes require further maturation to become functional.
Bone marrow destroys old RBCs by macrophages.
Bone marrow differentiates B lymphocytes.
Bone marrow stores iron in sinusoidal macrophages.

Hemopoiesis

Hemopoiesis is the production of all the blood cells.
Erythropoiesis is the production of RBCs.
Leukopoiesis is the production of WBCs.
Thrombopoiesis is the production of platelets.
Hematopoietic tissues produce new blood cells.
Hematopoietic tissues include the yolk sac, liver, and bone marrow.

Yolk Sac Phase

The yolk sac is the main site of hematopoiesis in the 2nd week of gestation.
The yolk sac is characterized by the formation of blood islands in the wall of the yolk sac.

Hepatic Phase

The liver is the main site of hematopoiesis from 8 weeks until 6-7 months of fetal life.
The liver contains hemopoietic centers that mainly produce erythrocytes, although some leukopoiesis occurs as well.
The liver is the major blood forming organ in the fetus during the second trimester.

Bone Marrow Phase

The bone marrow is the main site of hematopoiesis from the 2nd trimester of fetal life.
After birth, the bone marrow (the myeloid phase) and lymphatic tissues produce new blood cells.
In adults, hematopoiesis occurs mainly in the flat bones: sternum, pelvis, vertebrae, ribs, and the proximal ends of femur

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Description

This quiz explores the structure and function of bone marrow, including its role in hematopoiesis and the characteristics of red and yellow marrow. Additionally, discover the components of stroma and parenchyma that support hematopoietic cells. Test your understanding of these crucial aspects of the human skeletal system.