Question | Answer |
What are the 3 processes of hematopoiesis? | 1. Proliferation 2. Differentiation 3. Maturation |
Blood cells are replaced through the process of ______? | Proliferation |
Define differentiation. | Dividing cell gives rise to progeny that differ from it. |
Differentiated cells become fully functional through the process of what? | Maturation |
Megakaryopoiesis is the process of forming what type of cells? | Platelets |
The youngest form of a cell is known as a ______ cell. | Blast |
Progenitor cells come from stem cells under the influence of what? | Growth factors |
What cell marker is used to identify stem cells? | CD34 |
Erythrocytes, Leukocytes, and Platelets are committed (myeloid or lymphoid) progenitor cells. | Myeloid |
Lymphoid progenitor cells include what 3 types of cells? | B-cells, T-cells, and NK cells |
Progenitor cells make up what percent of precursor cells? | 3% |
What are 4 effects of growth factors? | 1. To promote cell survival
2. To control and regulate differentiation
3. To promote proliferation
4. To enhance functional activity of terminally differentiated progeny |
Growth factors are also known as _______. | Cytokines |
What are growth factors produced by? | Stromal cells in the bone marrow |
Growth factors work through the interaction with what? | Cell receptors |
What does it mean for a growth factor to be pleiotrophic? | That they are able to act on more than one cell type. |
Growth factors show redundancy, which means what? | More than one growth factor can have the same effect. |
Growth factors are (antagonistic or synergistic)? | Synergistic |
The JAK-STAT cytokine receptor is activated through what? | Phosphorylation |
Once JAK-STAT is activated,it sends signals to the cell to start what process? | Transcription |
Embryonic Hematopoiesis begins on what day of gestation? And occurs where? | Day 18; in the yolk sac |
Primitive erythroblasts come from ________ in the yolk sak? | Blood islands |
Fetal hematopoiesis begins in what month of developement? | The second month |
Fetal developement occurs where in the body? | Liver |
The liver is the primary site of hematopoiesis until what month in development? | The sixth month |
Adult hematopoiesis begins at what month of development? | The sixth month |
At the 6th month of fetal development, the liver decreases blood cell production and what takes over? | The bone marrow |
(Medullary or Extramedullary) hematopoiesis is considered normal in the adult. | Medullary - production occurs totally in the bone marrow unless a disease state causes fetal sites to begin production again. |
Red marrow is hematopoietically (active or inactive). | Active |
Inactive marrow occurs here where hematopoeitc tissue is replaced by adipocytes for structural support. | Yellow Marrow |
True or False: Children have less red marrow. | False, children have more red marrow. The more we age, the more adipocytes replace hematopoietic tissue. |
Define hematopoietic tissues. | The tissues and organs involved in proliferation, maturation, and destruction of blood cells. |
MALT stands for? | Mucosa-associated lymphoid tissue |
What are the 5 hematopoietic tissues? | 1. MALT
2. Spleen
3. Lymph Nodes
4. Thymus
5. Bone Marrow |
MALT is a collection of what three types of cells? | Lymphocytes, Monocytes, and Macrophages |
What are the primary roles of MALT? | Phagocytic and immunologic function. |
The largest collection of lymphocytes and mononuclear phagocytes are found in what hematopoietic tissue? | The spleen |
The spleen has what 4 functions? | 1. Culling
2. Pitting
3. Immunologic
4. Storage |
The removal of old cells is called what? | Culling |
What is the process of removing unwanted parts of a cell. | Pitting |
33% of the body's platelets are absorbed and stored by the _______? | Spleen |
The liver is (better or worse)than the spleen at pitting. | Worse due to the fact that blood flow is slower in the liver. |
Germinal centers become enlarged during ________? | Infection |
What is a Howell-Jolly Body? | A piece of DNA that is not removed during hematopoiesis. |
How does the spleen show an immunologic function? | It serves as a place of phagocytes and lymphocytes to mount a response. |
T-cells migrate to the _______ to acquire cellular markers. | Thymus |
What percent of T-cells actually leave the thymus with markers? | 5% |
The lymph node is the site of (T-cell or B-cell) maturation? | B-cells |
The lymph nodes have large amounts of what 2 cell populations? | Phagocytes and lymphocytes |
What is the primary site of hematopoeisis? | The bone marrow |
What is an erythroid island? | A central macrophage surrounded by developing red blood cells. |
What is the purpose of an erythroid island? | To transfer info between a macrophage to the surrounding red blood cells so that it may mature. |