Ch. 18 Blood-- Study Guide 1. Critically read pp. 683-704 before

“Leukocyte life cycle” section2. Comprehend Terminology (the text in bold) 3. Study-- Figure questions, Think About It

questions, and Before You Go On (section-ending) questions

4. Do end-of-chapter questions:– Testing Your Recall— 1, 3-6, 8, 9, 11, 12, 17-20– True or False– 1, 2, 3, 5, 8, 9– Testing Your Comprehension--1, 2, 3

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Chapter 18– Blood

The study of blood is called ___________

A-- Herpetology

B-- Hematology

C-- Homeostasis

D-- Hercules

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§ 18.1--Introduction

• Blood is a unique tissue; why?

• What kind of tissue?

Fig. 18.0

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CO 18

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An RBC, WBCs, and four platelets (SEM)

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§ Functions of Circulatory System

• Transport– O2, CO2, nutrients, wastes, hormones, and

heat

• Protection– WBCs, antibodies, and platelets

• Regulation – fluid regulation, buffering, body temp.

§ Two Components of BloodAdults have 4-6 L of blood

1.Plasma– 55% of total volume

Including—

2.Cellular (formed) elements— 45%

Including—

How to separate these two components? (see next slide Fig. 18.2)

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Figure 18.2

Hematocrit-- The percentage of the total blood volume that is occupied by __________ (see next slide)

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Cellular elements (= @ 46%)

Plasma = 55% of whole blood

“Buffy coat”<1%

A. Platelets

B. WBCs

C. Red blood cells =@45% of whole blood

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Assuming this tube contains a patient’s blood after centrifugation, what’s his/her blood hematocrit?

§ Seven Kinds of Formed Elements in Blood—

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1

4

3

2

5

7

6

Formed Elements of Blood

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1. Erythrocytes (RBCs)2. Platelets3. Leukocytes (WBCs)

A. Granulocytes—•Neutrophils (no. 3) •Eosinophils (no. 4)•Basophils (no. 5)

B. Agranulocytes—•Lymphocytes (no. 6)•Monocytes (no. 7)

§ Blood Plasma (top layer)Including– Table 18.2 (page 687)

1.Water (90% by weight)--• Most abundant molecule in the plasma• Function:

2.Electrolytes (Ions)– • What: sodium ions, …• Function:

3.Plasma proteins (8%)– (details next slide)

4.Others (2%)– Nutrients, . . .

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§ Plasma proteins (top layer)A.Albumins (60% of plasma proteins)–

Functions— transport molecules, the major contributor of osmotic pressure and blood viscosity etc.

B.Globulins (36%)– (alpha, beta and gamma)Functions– transport molecules, blood clotting factors, gamma-- antibodies

C.Fibrinogen (4%)– becomes fibrin, the major blood-clotting factor

• Where are plasma proteins formed?

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§ Blood Viscosity and Osmolarity• Blood Viscosity - resistance to flow

– Causes: Blood is thicker than water; Why?– Too much vs. too little

• Blood Osmolarity – Def. total molarity (concentration) of

dissolved particles in 1L of solution. . .– high osmolarity (compared with __________)

• causes fluid absorption into blood, raises BP

– low osmolarity • causes fluid to remain in tissues, may result in

edema (Example– see Fig. 18.3)

Fig. 18.3--Starvation and Plasma Protein Deficiency—Ascites and Kwashiorkor

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• Disc-shaped cell with thick rim– 7.5 M diameter and 2.0 m thick at rim– Blood types determined by surface

glycoprotein and glycolipids– cytoskeletal proteins (spectrin and actin)

give membrane durability; importance:

– Fig. 18.4 a and c

§ 18.2--Red Blood Cells (RBCs) or Erythrocytes

Figure 18.4a

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Fig. 18.4a

Figure 18.4c

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A Transmission Electron Microscope picture.

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§ Erythrocytes (RBCs) Function

• Gas transport - major function– increased surface area/volume ratio due to

________ shape– 98% of cytoplasm is hemoglobin (Hb)

• O2 delivery to tissue and CO2 transport to lungs

• Carbonic anhydrase (CAH) in RBC– produces carbonic acid from CO2 and water

– important role in gas transport and pH balance

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§ Hemoglobin (Hb) Structure• Globins - 4 protein

chains– 2 alpha and 2 beta

chains (HbA)– HbA vs. HbF--

• Heme groups– Conjugate with

each protein chain

– Bind O2; where?– How many in 1

Hb?

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§ Erythrocytes and Hemoglobin

• RBC count and hemoglobin concentration indicate amount of ______ blood can carry:– hematocrit (packed cell volume) - % of whole blood

composed of RBCs; 45% vs. 40% (M vs. F)– hemoglobin concentration of whole blood (g/dL); 16

vs. 14 (M vs. F)– RBC count; (millions RBCs/microliter ); 5.4 vs. 4.8

• Values are lower in women; Why?– Hormone (Testosterone)– Others

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§ Hemopoiesis1. Adult produces 400 billion platelets, 200 billion

RBCs and 10 billion WBCs every day

2. Hemopoietic tissues produce blood cells:A. Fetal life-- yolk sac produces stem cells, migrating to

Bone marrow, liver, spleen, thymus

B. (at birth) liver stops producing blood cells at birth

C. spleen remains involved with Lymphocytes production; Lymphoid hemopoiesis– where? Thymus etc.

D. red bone marrow • pluripotent stem cells, why?• myeloid hemopoiesis produces RBCs, WBCs and

platelets

18-22Our focus

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§ Erythrocyte Production (1)

• 2.5 million RBCs/sec, called Erythropoiesis• How long does the process take?• 4 major developments– in Cell size, Cell no.,

Hb, Cellular organellesA. Pluripotent stem cells become committed

cells – B. erythrocyte colony forming unit (ECFU)

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§ Erythrocyte Production (2)

C. Erythroblasts-- multiply and synthesize hemoglobin– Discard nucleus to form a reticulocyte

D. Reticulocytes— Name?– Characteristics:

E. Mature RBCs--

§ Erythrocyte Production (3)

Intracellular features of RBCs—– A. No nucleus & organelles (ribosome etc)

Why?– B. RBCs are plasma mem. sacs full of Hb

– C. Where is ATP produced in RBCs? By what key biochemical processes?

– D. When are key enzymes being produced?18-25

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§ Iron and Erythropoiesis (Fig. 18.7)

• Iron - key nutritional requirement, why?– Lost through urine, feces, and bleeding– requires dietary consumption of iron, ferric

(Fe3+) and ferrous (Fe2+) ions; Steps:

1.converts Fe3+ to absorbable Fe2+, where?

2.G-I tract— Gastroferritin binds Fe2+

3.In blood-- absorbed into blood and binds to Transferrin for transport

4.Liver-- Apoferritin binds Fe2+ to create ferritin for storage

Fig. 18.7 (iron metabolism)

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Good/excellent sources of iron: ?

In-class activity

• Give one disease related to low plasma proteins. Explain your answer.

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Other Needs for Erythropoiesis

• Vitamin B12 and folic acid:

– rapid cell division etc. (in the red bone marrow)– Where can red marrow be found in adults?

• In axial skeleton: girdles . . .

• Vitamin C and copper: – cofactors for enzymes synthesizing Hb

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§ Erythrocyte Homeostasis (1)

• Negative feedback control– What is the controlled

variable?– Hypoxemia-- causes– 1. Drop in RBC count

-- 2. Others (next slide)

Results:– EPO production

stimulates bone marrow

– RBC count in 3 - 4 days

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§ Erythrocyte Homeostasis (2)• Stimuli for erythropoiesis

– low levels O2; in Tibet, Himalaya

– increase in oxygen consumption

– less lung tissue available (emphysema)

– All these factors contribute to secondary polycythemia (details later)

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§ Erythrocytes Recycle/DisposalMacrophages in spleen, liver, & red bone marrow

1. Digest mem. fragment & separate heme from globin; Globins into free _______ (into blood)

2. Dispose/reuse the heme:– Iron (into blood); Heme converted to biliverdin

(green) and then bilirubin (yellow, into blood)– liver pick up & secretes bilirubin (into bile; small

intestine); bacteria create urobilinogen (brown feces)

– Some bilirubin becomes urochrome (into yellow urine) Fig. 18.9 and x

Fig. 18.9 Life & Death of RBCs

•Fate of RBC—•Life span–

•Where are RBCs’ final demise?

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Summary of RBC Life Cycle

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§ Erythrocyte Disorders• 1. Polycythemia - an excess of RBCs

– primary polycythemia• cancer of erythropoietic cell line in red bone

marrow– RBC count as high as 11 million/L; hematocrit 80%

– secondary polycythemia --• from dehydration, emphysema, high altitude, or

physical conditioning (all due to hypoxemia . . .)– RBC count up to 8 million/L

• Dangers of polycythemia– increased blood volume, pressure, viscosity

lead to embolism (obstruction of the blood vessels) . . .

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§ 2. Anemia – Causes/Categories• A. Inadequate erythropoiesis or hemoglobin

synthesis--– kidney failure and insufficient erythropoietin– inadequate vitamin B12 from poor nutrition or lack of

intrinsic factor (pernicious anemia)– iron-deficiency anemia– Hypoplastic and aplastic anemia – decline or

complete cessation of erythropoiesis

• B. Hemorrhagic anemia--• C. Hemolytic anemia– RBC destruction

TABLE 18.4 is an excellent table for review

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Anemia - Effects

• Tissue hypoxia and necrosis (the individual is short of breath and lethargic)– esp. Brain, heart, and kidney tissue

• Low blood osmolarity (→ tissue edema)

• Low blood viscosity (→ heart races and blood pressure drops)– heart failure

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§ 3. Sickle-Cell Disease1. Hereditary Hb ‘defect’; caused by recessive

allele modifies hemoglobin structure (HbS)– sickle-cell trait - heterozygous for HbS;

(HbA/HbS)– sickle-cell disease - ______________ for HbS

2. Details Fig. 18.10– HbS polymerize and become sickle shape; cell

stickiness causes agglutination and blocked vessels– intense pain in oxygen-starved tissues; kidney and

heart failure, stroke, paralysis; hemolysis of the fragile RBCs: anemia and hypoxemia

– chronic hypoxemia stimulates hemopoietic tissue (enlarged spleen, misshapen bones such as cranium)

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Sickle-Cell Diseased Erythrocyte

Fig. 18.10

Muddiest points of this chapter?

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