The fluid medium (blood) is a highly specialized connective tissue that consists of various blood cells (formed elements) suspended in a fluid matrix

Transcription

1 Blood In Detail

2 The fluid medium (blood) is a highly specialized connective tissue that consists of various blood cells (formed elements) suspended in a fluid matrix (blood plasma).

3 The formed elements comprise 45% of the total blood volume, it includes: Red blood cells (erythrocytes) White blood cells (leukocytes) Platelets (thrombocytes)

4 Plasma makes up the other 55% of the total blood volume. Plasma is 90% water, but includes dissolved substances such as gases, nutrients, hormones, waste products, ions, and plasma proteins.

5 Function of Blood: Transports substances: O 2, nutrients, wastes, & hormones Regulates: body temp, ph, and dissolved ions/proteins Protects: against infections/diseases and against excessive blood loss.

6 Three General Characteristics of Blood 37 C (98.6 F) is normal temperature but may actually be 1 F more above or below 98.6 F. High viscosity Slightly alkaline ph ( )

7 Formed Elements

8 White Blood Cell (WBC)

9 White blood cells (WBC), also known as Leukocytes is Greek, leukos means white and kytos meaning cell. WBC number in ,000 microliters of blood.

10 White blood cells (WBC) play a role in defending the body against infection. There are 5 WBC (leukocytes) types and they are categorized into 2 major groups: Granulocytes Agranulocytes

11 Granulocytes: have distinct granules in their cytoplasm and include: Neutrophils, eosinophils, and basophils

12 Agranulocytes: lack cytoplasmic granules, & include: Monocytes and lymphocytes

13 Platelets

14 Platelets are not true cells, but cytoplasmic fragments derived from cells called megakaryocytes.

15 Platelets have a critical role in the blood clotting mechanism & the repair of damaged blood vessels.

16 Red Blood Cell (RBC)

17 Erythrocytes is derived from the two Greek words: erythros, meaning red and kytos meaning cell. RBCs make up 99.9% of blood s formed elements. Thus when you examine a slide of a normal human blood smear, you should expect the vast majority of the cells that you observe to be RBC.

18 Abundance of RBCs Red blood cell count: the number of RBCs in 1 microliter of whole blood Male: million AND Female: million Hematocrit (packed cell volume, PCV): percentage of RBCs in centrifuged whole blood Male: AND Female: 37 47

19 RBC Production (called Erythropoiesis) occurs only in myeloid tissue (red bone marrow) in adults The Lifespan of RBCs is about 120 days Mature RBCs lack nuclei, mitochondria, & ribosomes & thus are unable to repair

20 Red blood cells (erythrocytes) are flattened & biconcave discs since they lack nuclei and most organelles. Most of the cytoplasm of the cell is filled with the red pigment protein, hemoglobin (Hb), that gives whole blood its color Hb transports respiratory gases & binds and transports oxygen and carbon dioxide

21 Hemoglobin Structure is a complex quaternary structure It has 4 globular protein subunits: Each with one molecule of heme Each heme contains one iron ion (Fe 2+ ) Iron ions Associate easily with oxygen (oxyhemoglobin) OR dissociate easily from oxygen (deoxyhemoglobin)

22 Oxygen Transport

23 Blood Typing

24 All cells have cell surface proteins that identify cells to the immune system Normal cells are ignored and foreign cells attacked Blood types are genetically determined by the presence or absence of RBC surface antigens: A, B, Rh (or D) There are four basic blood surface antigen types: A (surface antigen A) B (surface antigen B) AB (antigens A and B) O (neither A nor B)

25 Blood plasma antibodies are proteins that are produced by the body in response to a foreign antigen in the blood. Type A blood produces: Type B antibodies Type B blood produces: Type A antibodies Type AB blood produces: Neither A nor B antibodies Type O blood produces: Both A and B antibodies

26 Agglutinogens is a reaction in which RBCs suspended in a liquid collect into clumps due to a serological response to a specific antibody.

27 This is how blood typing works: plasma antibodies attack and agglutinate (clump) foreign blood surface antigens.

28 Blood Typing Figure 19 8 Blood Type Testing Copyright 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

29 The Rh (Rhesus) Factor also called the D antigen is found on the surface of RBC, and is also genetic. People are either Rh positive (Rh + ) or Rh negative (Rh - ) Only 15% of the US is Rh- Only sensitized Rh - blood has anti- Rh antibodies & this is important for pregnant women.