Blood Physiology

Question 1

Functions of blood

Answer 1

• Transport of:
• gases, nutrients, waste products
• processed molecules
• regulatory molecules
• regulation or pH and osmosis
• maintenance of body temperature
• proctor took against foreign substances
• clot formation

Question 2

What is the composition of blood?

Answer 2

Plasma - 55%
** made up of 7% proteins, 91% water, 2% other solutes**

Buffy coat - platelets and WBCs

RBCs - 45%

Question 3

List the plasma proteins and state what they do

Answer 3

ALBUMINS: viscosity, osmotic pressure, buffer, transports fatty acids, free bilirubin, thyroid hormones

GLOBULINS: transports lipids, carbohydrates, hormones, ions, antibodies, and complement

FIBRINOGEN: Blood clotting

Question 4

Components of plasma

Answer 4

Ions: osmosis, membrane potentials and acid base balance

Nutrients: glucose, amino acids, triacyglycerol, cholesterol, vitamins

Waste products:

• urea, Urica acid, creatinine, ammonia salts, breakdown products of protein metabolism
• lactic acid. End product of anaerobic respiration
• bilirubin. Breakdown product of RBCs

Gases: oxygen, carbon dioxide, and inert nitrogen

Regulatory substances: hormones, enzymes

Question 5

What are the formed elements?

Answer 5

1. RBCs - biconxave discs, anucleate, contain hempglobin; transports oxygen and carbon dioxide
2. WBCs
   - granulocytes
   - agranulocytes
3. Platelets (thrombocytes) - cell fragments. Form platelet plugs, release chemicals necessary for blood clotting.

Question 6

What is haematopoiesis

Answer 6

The process of blood cell production

Question 7

what are the cells formed from haematopoiesis?

Answer 7

Proerythroblasts: Develop into red blood cells
Myeloblasts: Develop into basophils, neutrophils, eosinophils
Lymphoblasts: Develop into lymphocytes
Monoblasts: Develop into monocytes
Megakaryoblasts: Develop into platelets

Question 8

what is the anatomy of RBCs

Answer 8

biconcave discs
lack a nucleus and other organelles
cannot reproduce
essentially consist of a plasma membrane, cytosol, and haemoglobin
each contains about 280 million haemoglobin molecules
lack mitochondria

Question 9

what is the function of RBCs (erythrocytes)?

Answer 9

TRANSPORT
carries oxygen from lungs to tissue: 98.5%
transports Carbon dioxide from tissue to lungs

Question 10

describe the composition of hemoglobin

Answer 10

• four globin molecules (polypeptide chains): transport carbon dioxide and nitric oxide.
• Four haem molecules, eahc containing one iron atom; transport oxygen
• Iron required for oxygen transport.

Question 11

what is erythropoietin?

Answer 11

is a hormone produced by the kidney that promotes the formation of red blood cells by the bone marrow, in response to low blood O2 levels.

Question 12

decribe the production of red blood cells

Answer 12

Stem cells → proerythroblasts → early erythroblasts → intermediate erythroblasts → late erythroblasts → reticulocytes

Question 13

function of leukocytes

Answer 13

Protect body against microorganisms and remove dead cells and debris

Question 14

describe the movements of Leukocytes

Answer 14

Ameboid: pseudopods
Diapedesis: cells become thin, elongate and move either between or through endothelial cells of capillaries
Chemotaxis: attraction to and movement toward foreign materials or damaged cells. Accumulation of dead white cells and bacteria is pus

Question 15

describe erythrocytosis

Answer 15

an increase in RBCs relative to the volume of blood. Polycythemiais an increase in both RBC concentration and hemoglobin, the protein in red blood cells that carries oxygen to the body’s tissues.

Question 16

describe the movement of neutrophils

Answer 16

after leaving bone marrow, stay in circulation 10-12 hours then move into other tissues. Become motile, phagocytoze bacteria, antigen-antibody complexes and other foreign matter. Secrete lysozyme. Last 1-2 days.

Question 17

describe the movement of Eosinophils

Answer 17

. Leave circulation and enter tissues during inflammatory response. Prevalent in allergic reactions. Destroy inflammatory chemicals like histamine. Release chemicals that help destroy tapeworms, flukes, pinworms, and hookworms.

Question 18

what is the movement of basophils

Answer 18

least common. Leave circulation and migrate through tissues, play a role in both inflammatory response and allergic reactions. Produce histamine and heparin.

Question 19

movement of lymphocytes

Answer 19

produced in red bone marrow but then migrate to lymphatic tissues and proliferate. Responsible for antibody production. Studied extensively with the immune system.

Question 20

movement of monocytes

Answer 20

remain in circulation for 3 days, leave circulation and become macrophages. Phagocytic cells. Can break down antigens and present them to lymphocytes for recognition

Question 21

list some blood disorders

Answer 21

Erythrocytosis: Increased circulating RBC number
Polycythemia: Increased RBC concentration
Anemia: Low oxygen-carrying capacity due to a deficiency of functional hemoglobin
Iron-deficiency
Pernicious
Hemorrhagic
Hemolytic
Sickle-cell

Question 22

define haemostasis

Answer 22

‘Arrest of bleeding’

the stop of blood flow

Question 23

define the three stages of haemostasis

Answer 23

3 events occur in rapid sequence to prevent excessive blood loss

• Vascular spasm: Vasoconstriction of damaged blood vessels. Can occlude small vessels. Caused by thromboxanes from platelets and endothelin from damaged endothelial cells.
• Platelet plug formation
• Coagulation or blood clotting

Question 24

describe platelet plug formation of hameostasis

Answer 24

1. platelet adhesion
2. platelet release reaction.
3. platelet aggregation
4. expression of coagulation factor V and Phospholipids.

Question 25

stages of coagulation

Answer 25

1. Activation of prothrombinase 2. Conversion of prothrombin to thrombin 3. Conversion of fibrinogen to fibrin

Question 26

types of clot formation

Answer 26

extrinsic and instrinsic

Question 27

describe extrinsic clotting

Answer 27

Stage 1: Damaged tissues release tissue factor (TF; factor III) When Ca2+ is present, forms complex with factor VII, activating factor X Prothrombinase is formed Stage 2: prothrombinase converts prothrombin into thrombin Stage 3: Thrombin converts fibrinogen to fibrin Thrombin activates factor XIII, which stabilizes clot

Question 28

describe instrinsic clotting pathways

Answer 28

Stage 1 In damaged blood vessels, factor XII comes in contact with exposed collagen, activating factor XII Stimulates factor XI, activates factor IX Activated factor IX joins with factor VIII, platelet phospholipids and Ca2+ to activate factor X Prothrombinase is formed Stages 2 and 3 progress to clot formation

Question 29

control of clot formation

Answer 29

anticoagulants: prevent coagulation factors from initiating clot formation. coagulation : occurs when coagulation factor concentration exceeds a given threshold. At site of injury, threshold is exceeded. Anticoagulants Antithrombin: produced by liver, slowly inactivates thrombin Heparin: produced by basophils and endothelial cells. Increases effectiveness of antithrombin Prostacyclin: prostaglandin derivate from endothelial cells. Causes vasodilation and inhibits release of coagulating factors from platelets

Question 30

define fibrinolysis in clot retraction

Answer 30

Clot retraction. Fibrin threads of clot attached to blood vessel walls. Platelets produce processes that attach to fibrin threads. Actin and myosin molecules within platelets contract, pulling edges of wound together and squeezing out serum. Clot dissolved by activity of plasmin, an enzyme which hydrolyzes fibrin

Question 31

define transfusion and infusion

Answer 31

Transfusion: transfer of blood or blood components from one individual to another Infusion: introduction of fluid other than blood

Question 32

how is blood grouped?

Answer 32

Determined by antigens (agglutinogens) on surface of RBCs Antibodies (agglutinins) can bind to RBC antigens, resulting in agglutination (clumping) or haemolysis (rupture) of RBCs Groups: ABO and Rh

Question 33

describe the ABO blood groups

Answer 33

A and B antigens Type A blood has A antigen only Type B blood has B antigen only Type AB blood has both A and B antigens Type O blood has neither A nor B antigens Four different blood types, caused by the presence or absence of two RBC antigens

Question 34

describe a transfusion reaction

Answer 34

If transfused blood is not matched to the recipients blood it will cause a transfusion reaction this measn that antibodies attack antigens, causing the RBC to clump together (agglutinate) and break the cells open killing them (lysis)

Question 35

what is an agglutination test?

Answer 35

Before blood is transfused, agglutination tests are used to determine blood type Take a blood sample and add anti-A and anti-B antibodies to it, to see if either antibody causes agglutination E.g. Type A blood will form clumps if exposed to anti-A but not to anti-B antibody

Question 36

What anions and cations make up electrolytes?

Answer 36

Positively charged cations: Calcium Sodium Potassium Negatively charged anions: Phosphate Sulfate Bicarbonate

Question 37

describe the regulation of clot formation and how clots are removed

Answer 37

when a person cuts themselves, eg their finger, some blood is spilt, and due to the walls of the blood vessels being open, the platelets are exposed to the collagenous fibres, binding, which then turns the platelets sticky, allowing them to clump together to form a barrier, blocking the open section. fibrin then attached on top of the covering platelets and then binds the vessel back together. the clot then dissolves after a few days

Question 38

describe Rh

Answer 38

rhesus antigens, you may be Rh positive or Rh negative. eg, O-, AB+ Rh positive can receive both antigens ( + and -) Rh negative should just receive their negative antigens.

Question 39

describe the Hemolytic disease of the Newborn (HDN)

Answer 39

when a mother is negative Rh but the child in womb is Rh positive. it is okay for the first time, but after first birthing in this situation, the mother will develop Rh + antibodies which will fight in a secondary Rh positive pregnancy.