Function and Formation of Blood Study Guide

Question 1

items transported in the blood

Answer 1

Nutrients
Gasses
Hormones
waste

Question 2

describe the composition and physical characteristics of whole blood. Why is it classified as connective tissue?

Answer 2

red blood cells, white blood cells, and platelets suspended in a protective yellow liquid known as plasma.
- Sticky, opaque liquid
- Color varies from scarlet red to maroon
- Metallic taste
- Slightly alkaline (pH 7.35 to 7.45)
- Slightly warmer than body temperature
- 5x more viscous than water – viscosity determined by hematocrit

Question 3

general pathway of blood circulating in the human body

Answer 3

• Circulation of blood is initiated by the pumping action of the heart
• Oxygen-rich blood is pumped out of the heart via arteries
• Arteries repeatedly branch until they become capillaries
• At capillaries, Oxygen and nutrients exit the blood to enter the body’s tissues; Carbon Dioxide and waste enter the blood
• Oxygen-poor blood flows into veins which repeatedly converge
• Oxygen-poor blood enters the heart, moves to the lungs, returns to the heart
• Oxygen-rich blood exits the heart via arteries

Question 4

type of blood vessel that is the site of gas and nutrient exchange

Answer 4

Capillaries

Question 5

transport functions of whole blood

Answer 5

• Transport O2 from the lungs and nutrients from the digestive tract to body cells
• Transport waste to elimination sites
  
  • The lungs eliminate CO2
  • The kidneys eliminate nitrogenous wastes via urine
• Transport hormones from endocrine organs to target organs
  
  • Example: growth hormone is secreted from the anterior pituitary gland to the bones

Question 6

Maintenance/Regulatory Functions

Answer 6

• Maintain appropriate body temperature by absorbing and distributing heat
• Maintain normal pH in body tissues (~7.35 to 7.45)
• Maintain necessary fluid volume to adequately perfuse body tissues

Question 6

buffy coat

Answer 6

% of blood made up by leukocytes and platelets

Question 6

Hematocrit

Answer 6

% of blood made up by erythrocytes

Question 6

protective functions

Answer 6

• Prevent blood loss through clotting
• Prevent infection by defending against foreign invaders

Question 7

3 formed elements of blood + their relative percentages

Answer 7

Erythrocytes: Red Blood Cells (45% BV)
Leukocytes: White Blood Cells (< 1% BV)
Platelets: Cell Fragments (< 1% BV)

Question 8

average blood volume in adult males and females

Answer 8

adult males 5-6L (1.5 gallons), adult females about 4.5-5.5 liters (1.2 gallons)

Question 9

formed element that is a true cell

Answer 9

leukocytes

Question 10

typical lifespan of erythrocyte

Answer 10

100-120 days

Question 11

where does hematopoiesis take place?

Answer 11

within red bone marrow of the bones and girdles of the axial skeleton

Question 11

how do erythrocytes get replaced?

Answer 11

stem cells dividing in red bone marrow (not cellular mitosis)

Question 12

hematopoiesis

Answer 12

creation of all blood cells

Question 13

stem cell that gives rise to blood cells

Answer 13

hemocytoblast

Question 14

reasons why erythrocytes are able and efficient at carrying Oxygen

Answer 14

small + flexible so they fit through narrow vessels, have bi-concave shape which maximizes surface area to absorb oxygen, have thin membrane so gasses easily diffuse through, + contain hemoglobin which binds to oxygen.

Question 15

How does Oxygen bind to erythrocytes?

Answer 15

Hemoglobin – iron containing protein that binds oxygen to the RBC

Question 16

dangers of too few erythrocytes

Answer 16

leads to tissue hypoxia - O2 deprivation

Question 16

How many Oxygen molecules can 1 erythrocyte carry?

Answer 16

Around 1 billion oxygen molecules

Question 17

normative values for hemoglobin in adult males and females

Answer 17

Male: 13-18g/100mL
Female: 12-16g/100mL

Question 18

hormone that triggers creation of erythrocytes

Answer 18

Erythropoietin (EPO)

Question 19

dangers of too many erythrocytes

Answer 19

leads to excessive blood viscosity (thickening)

Question 20

events that triggers secretion of EPO

Answer 20

• Reduced numbers of erythrocytes as might occur after hemorrhage (bleeding)
• Insufficient hemoglobin as might occur in iron deficiency
• Reduced availability of O2 as might occur at high altitude or during respiratory illness
• Testosterone also enhances the kidneys’ production of EPO

Question 21

3 erythrocyte disorders

Answer 21

anemia
sickle cell anemia
polycythemia

Question 22

sickle cell anemia

Answer 22

excessive RBC destruction caused by abnormal, misshapen Hgb molecules
- RBCs are crescent shaped; tend to clog small blood vessels and/or rupture
- Symptoms: shortness of breath and extreme pain
- Most prominent in the malaria belt of Africa – the gene that causes mishappen Hgb can offer some protection against malaria

Question 22

anemia

Answer 22

a decrease in the O2 carrying capacity of blood
- Symptoms: fatigue, pallor, shortness of breath, and feeling chilled
- Causes: acute or chronic blood loss, low RBC production, excess RBC destruction
- Causes of Low RBC Production: deficiency of iron, B12, EPO, or red bone marrow

Question 23

Polycythemia

Answer 23

an excessive or abnormal increase in the number of RBCs
- Causes: bone marrow cancer, living at high altitude, “blood doping”
- Excessive amounts of RBCs increase blood viscosity – blood flows sluggishly; clots become more likely

Question 24

What is blood doping? How would it benefit competitors in aerobic sports?

Answer 24

Increased amount of RBCs → increased amount of hemoglobin → boosts the amount of oxygen able to be supplied to the muscles, which enhanced endurance