A&P Chapter 18 Blood

Question 1

What are the functions of the circulatory system?

Answer 1

Transport: Carries O2 and CO2 as well as nutrients and wastes. Carries hormones from endocrine cells to their target organs. Transports a variety of stem cells to the tissues where they lodge and mature.

Protection: WBC’s destroy microorganisms and cancer cells. Antibodies and other blood proteins neutralize toxins and help destroy pathogens. Platelets secrete clotting factors to minimize blood loss.

Regulation: Stabilize fluid distribution in the body. Buffer acids/bases, blood proteins help stabilize the pH of the extra cellular fluids. Blood helps regulate body temp by moving warm blood to the surface to cool and constricting surface vessels for warmth retention.

Question 2

How many formed elements in blood are there?

Answer 2

7. Erythrocytes, Platelets and Five Leukocytes.

Question 3

What are the different types of Leukocytes in the blood stream?

Answer 3

There are 3 Granulocytes, the Neutrophils, Eosinophils, and the Basophils.

There are 2 Agranulocytes, the Lymphocytes and the Monocytes.

Question 4

What is the average volume of blood?

Answer 4

4-5L in Females 5-6L in Males

Question 5

What are the components of blood?

Answer 5

Plasma (55%), Erythrocytes (45%) and Leukocytes and Platelets (<1%)

Question 6

What is the range for normal blood pH?

Answer 6

7.35-7.45

Question 7

How many RBC’s are in an ml of blood?

Answer 7

4.5-5.5 million

Question 8

How many platelets are in an ml of blood?

Answer 8

?

Question 9

Where are blood cells produced?

Answer 9

In Hemopoietic tissues. The Liver stops producing blood cells by birth, the spleen stops producing RBC’s shortly after but continues to produce lymphocytes for life .

The Red Bone Marrow produces all seven kinds of formed elements of blood. In adults in the heads of long bones and in the pelvis.

Question 10

Describe Hemoglobin

Answer 10

It consists of 33% of the cytoplasm of a RBC.

It gives RBC’s their color and is vital in the role of transporting O2 and CO2.

Hemoglobin consists of 4 protein chains called GLOBINS.

Question 11

What are the different protein chains in hemoglobin?

Answer 11

A normal adult hemoglobin has 2 alpha chains with 141 aminoacids and 2 beta chains with 146 aminoacids.

Question 12

Describe the Heme group

Answer 12

Each globin protein chain in hemoglobin is conjugated with a heme group. The heme group centers around an Fe2+ ion which binds a molecule of O2.

Question 13

How many molecules of O2 can a single molecule of Hemoglobin carry?

Answer 13

Four molecules of O2. There are four heme groups each with a Fe2+ ion.

Question 14

What happens when hypoxemia occurs?

Answer 14

The body will produce more RBC’s (erythropoiesis) to attempt to bring the oxygen levels in the blood back up to normal.

Low blood oxygen is detected by cells in the Kidneys which then secrete erythropoietin which speeds up and stimulates the production of erythrocytes.

Question 15

How long does an average Erythrocyte live for? Where are they disposed of at?

Answer 15

They live for approx. 120 days and are broken down by the liver and spleen when they expire.

Question 16

Uncontrolled diabetes can lead to what blood ph issue?

Answer 16

Acidosis where the blood pH drops below 7.35 to 7.3 or so. The opposite is Alkalosis where the pH climbs to 7.5 or 7.55.

Question 17

Describe Erythrocytes:

Answer 17

They function to transport Oxygen and Carbon Dioxide.

They are 7.5 micrometers wide and 2 micrometers thick.

They have NO Nucleus.

There are approx. 4.5-5.5 million in a cubic millimeter and 4.5-5.5. Billion in a cubic centimeter.

Males tend to have more erythrocytes but females tend to have more efficient erythrocytes.

Question 18

Describe Hemoglobin:

Answer 18

Fills cytoplasm of Erythrocytes.

Contains 4 Globin protein molecules all with a Heme group in the center.

The Heme group has a Fe2+ ion in the center which allows Oxygen and CO2 to bind REVERSEBLY.

Each molecule of Hemoglobin can bind 4 molecules of O2 or CO2.

Carbon Monoxide will bind to the Fe2+ in the Heme group but it will not bind reversibly, it will not come undone.

Question 19

Erythropoiesis is? Where does it occur? What are developing Erythrocytes called?

Answer 19

The formation of Erythrocytes, it occurs in the RED bone marrow of the flat bones in the Illum and the Sternum. Developing Erythrocytes are called Erythroblasts.

In Infants the LIVER is a site of Erythropoiesis, if an adult has chemotherapy and the red bone marrow is killed off the Liver can begin producing RBC’s again.

Question 20

What is Hypoxemia? Explain how Hypoxemia stimulates the production of RBC’s? Why?

Answer 20

Hypoxemia is Low Oxygen in the Blood. Cells in the liver and kidneys sense how much O2 is circulating and if it becomes low they will produce ERYTHROPOIETIN which is a hormone that circulates to the Red Bone marrow and increases the production and development of new Erythrocytes.

This results in more circulating RBC’s which can carry O2 which ultimately results in a higher amount of circulating oxygen.

Lance Armstrong was blood doping resulting in a higher number of circulating RBC’s and a competitive advantage.

Question 21

What are antigens on the surface of the RBC’s? Why are they there? What happens if you get blood with the wrong antigens?

Answer 21

The antigens are glycoproteins that allow the body to recognize foreign cells from it’s own. The antigens are responsible for your blood type.

If you get a blood transfusion from someone with an incompatable blood type the RBC’s with the wrong antigens will be affected by antibodies resulting in AGGLUTINATION and stick together forming clumps/clots.

Question 22

How long do RBC’s typically last in circulation? Where are they destroyed?

Answer 22

They are in circulation for approx. 120 days. They are trapped and destroyed in the spleen and liver.

The Iron (Fe2+) is recycled for use else where in the body.

Question 23

Describe Leukocytes: Where are they formed? How many are there? What do they do?

Answer 23

There are five different types, they make up your White Blood Cells. All play a part in body defenses, protection and immune response.

All are formed in the Bone Marrow and some can be produced in the lymph nodes or even in the dermis of the skin. They exist in the blood but are not particularly active in the blood, they use the blood as a method of transportation.

There are 4,000-10,000/cubic milliliter and 4-10million/cubic centimeter.

There are 5 leukocytes broken into two categories, granulocytes and agranulocytes based on how they accept or reject stains in lab preparation.

Question 24

What are the Granulocytes?

Answer 24

Neutrophils, Basophils and Eosinophils

Question 25

What are the Agranulocytes?

Answer 25

Lymphocytes and Monocytes

Question 26

Describe Neutrophils

Answer 26

They make up 40-60% of circulating WBC's in the blood. Neutrophils stick around in the blood, they play an immune/defense role in the blood stream. Granules are present but stain weakly with both acidic and basic stains. Has ONE nucleus with as many as 3-7 lobes connected by a thin strand. ALSO CALLED PMN Leukocytes or Polymorphoneuclear Leukocytes. Neutrophils can eat things, they contain enzymes that help break things down to be disposed of.

Question 27

Describe Eosinophils

Answer 27

Make up 1-4% of circulating Leukocytes in the blood. The granules in the cytoplasm attract ACIDIC stain EOSIN and stain a red or orange color. The nucleus is indented or bilobed. Eosinophils attack PARASITES. They also play a role in allergic reactions by eating the antibodies and antigens from a reaction.

Question 28

Describe Basophils

Answer 28

They make up 0.5-1% of circulating WBC's in the blood. The granules attract the BASIC stain HEMATOXYLIN and stain blue or purple. The nucleus is indented or bilobed but is USUALLY OBSCURED BY THE GRANULES. In the BODY they are the MAST CELLS found in connective tissues especially. They release vesicles filled with Heparin and Histamine.

Question 29

Describe Monocytes

Answer 29

They consist of 4-8% of the WBC's circulating in the blood. The Nucleus is indented, may be kidney or horseshoe shaped. The Cytoplasm is abundant and is typically a light blue color. Very large cells. In the rest of the body these become Macrophages which engulf and eat other items.

Question 30

Describe Lymphocytes

Answer 30

They make up 20-40% of the WBC's in the blood. The Nucleus is usually spherical, slightly indented and it stains a darker blue color. There is a varying amount of cytoplasm depending on how active the cell has been or is at the moment. The larger the lymphocyte the more active it is. The nucleus stays the same size but the cytoplasm changes amount.

Question 31

What are the two types of Lymphocytes?

Answer 31

T Cells and B Cells.

Question 32

What is DIAPEDISIS?

Answer 32

The process by which Leukocytes can SQUEEZE between the simple squamous epithelia of the blood vessel walls and get into and out of the blood vessels.

Question 33

Where do most leukocytes play the largest roles? How do they get there?

Answer 33

In the connective tissues of the body, they get there by travelling through the blood to a specific destination and then using the process of DIAPEDISIS they exit or re-enter the blood stream to reach a target destination.

Question 34

Describe Platelets:

Answer 34

1 Micron thick, typically 250-500,000/cubic milliter. They play a primary role in the clotting of blood vessels when they are broken. They are living fragments of MEGAKARYOCYTES that leave the bone marrow and circulate with the blood.

Question 35

What is HEMOSTASIS?

Answer 35

The stopping of blood so the body can repair an injury. It involves three processes in rapid sequence. Vasospasm, Formation of a Platelet Plug and the Formation of a Fibrin Clot.

Question 36

Describe the Three Phases of Hemostasis

Answer 36

Vasospasm: The affected blood vessel constricts and gets smaller. Platelet Plug: Chemicals released by the injured vessel cause platelets to attach to each other and to the injured part of the vessel, this is called PLATELET ACTIVATION. As new platelets attach they also release activation chemicals causing more and more platelets to clump together at the injury site. Fibrin Clot: Is formed when a series of sequential chemical reactions (clotting factors) are carried out which ultimately uses Thrombin to convert the protein molecule Fibrinogen which is freely circulating in blood plasma to Fibrin forming a clot. The clot traps everything, platelets, RBC's and WBC's. Once the clot has formed it is stabilized by COVALENT CROSSLINKS among the strands of Fibrin. Over the next 30-60min the clot RETRACTS becoming more dense and solid finally resulting in a dense network of fibrin with the RBC's, WBC's and Platelets trapped inside.

Question 37

Explain how the clotting factors allow for fast activation of a clot but also build in a safeguard against unwanted clotting?

Answer 37

The clotting factors build on the previous one, without the previous chemical factor the process stops and no clot is formed. This affords many safeguards against unwanted clotting.

Question 38

What is Fibrinolysis?

Answer 38

The process by which a clot is dissolved and removed.

Question 39

Explain how Fibrinolysis occurs.

Answer 39

Plasminogen circulating in your blood plasma is converted to an active enzyme (remember enzymes are the biological catalysts that speed up and slow down reactions) PLASMIN which dissolves Fibrin.

Question 40

Why are older people more likely to get an embolus?

Answer 40

Because they are 1. typically less active allowing the blood in their legs to slow down and pool which initiates clotting. 2. they have less Plasminogen in their blood plasma to properly dissolve clots. This results in a potential embolus.