Blood

Question 1

Blood

Answer 1

Specialized connective tissue consisting of living cells suspended in blood plasma

Question 2

Functions of blood

Answer 2

• Transport: Delivers oxygen and nutrients to parts of the body, transports hormones and metabolic wastes for elimination
• Regulatory: maintains body temperature, pH and fluid balance (homeostasis)
• Protective: Prevents blood loss and fights infections (WBCs)

Question 3

Composition of blood

Answer 3

• Blood plasma: contains dissolved elements, 55% of the blood
• Buffy coat: white blood cells and platelets, 1% of the blood
• Erythrocytes: densest element found in blood, red blood cells, 45% of the blood

Question 4

Hematocrit

Answer 4

This represents the percentage of erythrocytes in the whole blood

Question 5

Anemia

Answer 5

This is a low hematocrit which is indicating a lack of red blood cells
- Blood loss; hemorrhagic anemia
- Not enough blood production: iron-deficiency anemia, renal anemia (low EPO) or aplastic anemia (destruction of the red bone marrow)

Question 6

Polycythemia

Answer 6

This is a high hematocrit which indicates an elevated number of red blood cells due to oxygen deficiency
- May increase blood viscosity

Question 7

Normal hematocrit ranges

Answer 7

Adult females: 37-47% with an average of 41%
Adult males: 42-52% with an average of 47%

Testosterone increases the production red blood cells which is why men have a higher hematocrit range them women

Question 8

Characteristics of blood

Answer 8

• Slightly basic fluid with high density and viscosity
• Plasma consists of mostly water and solutes including nutrients, gases, hormones, ions etc

Question 9

Formed elements of blood

Answer 9

Erythrocytes: no nucleus
Leukocytes: complete cells
Platelets: cell fragments

Question 10

Erythrocytes

Answer 10

• Also known as red blood cells
• Biconcave in shape; for gas exchange
• Lack nuclei and most organelles
• Contains mostly hemoglobin
• Only use anaerobic ATP so they don’t consume the O2 being carries

Question 11

Hemoglobin

Answer 11

• Protein consisting of four polypeptide chains of globin proteins each with a heme group
• Heme: Contains an iron atom as a binding site for O2

Question 12

Oxyhemoglobin

Answer 12

Formed when oxygen diffuses into the blood in the lungs and binds to hemoglobin

Question 13

Deoxyhemoglobin

Answer 13

Dark red blood is formed in body tissues when oxygen detaches from the iron in hemoglobin

Question 14

Carbaminohemoglobin

Answer 14

This is formed when about 20% of the CO2 in the body binds to the amino acids on the globins

Question 15

Arterial Blood Gas (ABG) analysis

Answer 15

The most accurate way to measure someone’s blood oxygen level
- Done by taking a sample of blood from the forearm or groin

Question 16

Functions of ABG analysis

Answer 16

Tells us about;
- Arterial blood oxygen
- Arterial blood CO2
- Blood pH
- how well gas exchange is functioning in the lungs

Question 17

Pulse oximetry

Answer 17

Estimates the percentage of hemoglobin that’s oxygen-saturated based on the absorption of light at two different wavelengths
- Cannot determine metabolism or CO2 levels

Question 18

Hematopoiesis

Answer 18

• Blood cell formation
• Occurs in the red bone marrow
• All blood cells form from the hemocytoblast (a stem cell)

Question 19

Hemocytoblast

Answer 19

After mitosis, some cells remain stem cells and others become
- Myeloid stem cells: form platelets, erythrocytes and some kinds of leukocytes
- Lymphoid system cells: form lymphocytes

Question 20

Erythropoiesis

Answer 20

The formation of erythrocytes
- begins when a hematopoietic stem cell is transferred to a proerythroblast
- Hemoglobin synthesizes, iron accumulates
- Hemocytoblast -> Proerythroblast -> Basophillic erythroblast -> polychromatic erythrocblast -> orthrochromatic erythroblast -> reticulocyte -> RBC
- Reticulocyte (immature RBC) ejects most organelles, the nucleus degenerates, cell assumes the biconcave shape
- This process required iron, vitaminB12, folic acid, proteins, lipids and carbohydrates

Question 21

Erythropoietin (EPO)

Answer 21

• This hormone controls erythrocyte production
• Produced mostly by kidneys when they are lacking oxygen (hypoxic)
• Triggered but the loss of RBCs, insufficient hemoglobin or reduced availability of oxygen
• Enhanced by testosterone

Question 22

Breakdown of erythrocytes

Answer 22

• Destruction of dead/dying RBCs happen by macrophages in the spleen
• Globin is broken down to amino acids and the iron from heme is salvaged
• Remaining heme is degraded to bilirubin, secreted in bile to the intestine

Question 23

Blood doping

Answer 23

Artificially inducing polycythemia to try to get an advantage in athletic competitions
- Typically done by injecting synthetic erythropoietin