Presentation is loading. Please wait.

Presentation is loading. Please wait.

Pages 349-353.  The process of blood cell formation ◦ Includes all blood cells- red and white  Occurs in red bone marrow from stem cells known as hemocytoblasts.

Similar presentations


Presentation on theme: "Pages 349-353.  The process of blood cell formation ◦ Includes all blood cells- red and white  Occurs in red bone marrow from stem cells known as hemocytoblasts."— Presentation transcript:

1 Pages 349-353

2  The process of blood cell formation ◦ Includes all blood cells- red and white  Occurs in red bone marrow from stem cells known as hemocytoblasts ◦ Hemocytoblast differentiation  Lymphoid stem cell produces lymphocytes  Myeloid stem cell produces all other formed elements © 2015 Pearson Education, Inc.

3 Lymphoid stem cells Myeloid stem cells Hemocytoblast stem cells Secondary stem cells Erythrocytes Platelets Basophils Eosinophils NeutrophilsMonocytesLymphocytes

4  Because RBCs are anucleate they cannot divide, grow, or synthesize proteins  Life span of 100 to 120 days  phagocytes in the spleen/liver eliminate remains  New RBCs produced by hemocytoblasts in the red bone marrow (a 3-5 day process) © 2015 Pearson Education, Inc.

5  erythropoietin : hormone that controls RBC production rate  Produced by kidneys in response to O 2 levels  Targets bone marrow to mfr RBCs  negative feedback maintains blood oxygen levels (see figure 10.5 on page 346)  works by increasing/decreasing erythropoietin release © 2015 Pearson Education, Inc.

6 Stimulus Homeostasis: Normal blood oxygen levels 1 IMBALANCE Low blood O 2 –carrying ability due to Decreased RBC count Decreased amount of hemoglobin Decreased availability of O 2 Kidney (and liver, to a smaller extent) releases erythropoietin. 2 Erythropoietin stimulates red bone marrow. 3 Enhanced erythropoiesis increases RBC count. 4 O 2 –carrying ability of blood increases. 5 Slide 1

7  A group of Colony stimulating factors (CSFs) and interleukins prompt bone marrow to generate leukocytes  CSFs are specific to the types of WBCs they act on  used to stimulate cell production in cancer patients undergoing chemo or radiation therapy  Hormone thrombopoietin stimulates production of platelets from megakaryocytes © 2015 Pearson Education, Inc.

8  involves three phases: 1.Vascular spasms 2.Platelet plug formation 3.Coagulation (blood clotting) © 2015 Pearson Education, Inc.

9  Vasoconstriction causes blood vessel to spasm  Narrowing of the blood vessel  Slows blood loss © 2015 Pearson Education, Inc.

10 Vascular spasms occur. 1 Step Smooth muscle contracts, causing vasoconstriction. Slide 2

11  Collagen fibers are exposed by a break in a blood vessel  Platelets become “sticky” and cling to fibers  Anchored platelets release chemicals to attract more platelets  A positive feedback mechanism  Platelets pile up to form a platelet plug (white thrombus) © 2015 Pearson Education, Inc.

12 Collagen fibers Platelet plug forms. Step Injury to lining of vessel exposes collagen fibers; platelets adhere. Platelets release chemicals that make nearby platelets sticky; platelet plug forms. Platelets Slide 3 2

13  Clotting factors in blood plasma and injured tissue cells interact with Ca²⁺ to produce the enzyme thrombin ◦ Thrombin catalyzes the joining of fibrin molecules to make a meshwork that traps RBCs and platelets ◦ This forms the clot, which is broken down after repair of damaged tissue  This mechanism is controlled so that the presence of the clot inactivates the factors that initiated the response ◦ To avoid clotting of all blood in the body ◦ http://tube.medchrome.com/2010/10/hemostasis-and-coagulation- cascade.html http://tube.medchrome.com/2010/10/hemostasis-and-coagulation- cascade.html © 2015 Pearson Education, Inc.

14 Coagulation events occur.Step Clotting factors present in plasma and released by injured tissue cells interact with Ca 2+ to form thrombin, the enzyme that catalyzes joining of fibrinogen molecules in plasma to fibrin. Fibrin forms a mesh that traps red blood cells and platelets, forming the clot. Fibrin Slide 4 3

15

16  Thrombus  A clot in an unbroken blood vessel  Can be deadly in areas such as the heart  Embolus  A thrombus that breaks away and floats freely within the bloodstream  Potential to clog vessels in critical areas  Potential causes:  Burns  Physical blows  Fatty material (plaque)  Slow blood flow © 2015 Pearson Education, Inc.

17  Thrombocytopenia  Platelet deficiency  Results from bone marrow suppression  Cancer, radiation, drugs, autoimmune condition, bacteria  Evidenced by petechiae (purplish skin blotches)  Liver problems  due to cirrhosis, hepatitis, or low Vitamin K stores  Liver synthesizes the clotting proteins  Hemophilia  Hereditary bleeding disorder  Normal clotting factors are missing © 2015 Pearson Education, Inc.


Download ppt "Pages 349-353.  The process of blood cell formation ◦ Includes all blood cells- red and white  Occurs in red bone marrow from stem cells known as hemocytoblasts."

Similar presentations


Ads by Google