Chapter 19 - Blood

Question 1

Blood

Answer 1

A fluid filled connective tissue which is about 8% of our body weight.

Question 2

What is the average pH of blood?

Answer 2

7.35 - 7.45 (neutral - similar to water)

Question 3

In litres, what is the volume of blood needed for adult males and females?

Answer 3

Males: 5-6 litres

Females: 4-5 litres

Question 4

What does the darkness of blood signify?

Answer 4

Bright red blood = oxygen rich

Dark red blood = oxygen poor

Question 5

What are the 3 functions of blood?

Answer 5

1. Transport oxygen and nutrients to cells, and wastes away from cells.
2. Regulate body temp, pH of tissues, water content in tissues.
3. Protect against blood loss by clotting, and against infection by WBC’s.

Question 6

What is blood composed of?

Answer 6

1. Plasma - (55%) a watery fluid that contains dissolved substances.
2. Formed elements - (45%) red blood cells, white blood cells, platelets

Question 7

What is the transport pathway of blood?

Answer 7

1. Lungs and gut give 02 and nutrients
2. Those go into the blood
3. Interstitial fluid
4. Body cells
5. CO2 and waste
6. Interstitial fluid
7. Blood
8. Kidneys, skin, lungs

Question 8

Blood plasma

Answer 8

The fluid portion of blood composed of 90% water and 10% solutes.

Solutes include: electrolytes, nutrients, enzymes, hormones, gases, metabolic wastes, and plasma proteins produced by the liver

Question 9

What are the names of the 3 main plasma proteins and how much do they account for in the plasma?

Answer 9

1. Albumin - 54% of plasma proteins
2. Globulins - 38% of plasma proteins
3. Fibrinogens - 7% of plasma proteins

These account for 8% of the 10% of solutes in plasma

Question 10

Albumin

Answer 10

A plasma protein which:

• helps with the maintenance of osmotic pressure (keeping water in blood plasma)
• acts as a buffer to maintain pH
• it is a carrier molecule of fatty acids and steroid hormones

Question 11

Globulins

Answer 11

A plasma protein with 2 subdivisions:

1. Alpha and beta globulins - transport iron, metals, lipids, fat-soluble vitamins.
2. Immunoglobulins - antibodies which are released by plasma cells during immune response.

Question 12

Fibrinogen

Answer 12

A plasma protein which is a precursor of fibrin and helps with blood clotting

Question 13

Red blood cells (RBC’s)

Answer 13

Function to transport respiratory gases (O2, CO2)

Each RBC contains about 250mil molecules of hemoglobin.
Each hemoglobin molecule is made of 4 polypeptide chains, and an iron containing “heme” pigment bound to each of the 4 chains.

Question 14

Why do red blood cells contain no nucleus or organelles? How do they generate ATP?

Answer 14

Mature RBC’s pinch off their nucleus and other organelles to increase the surface area of oxygen transport.

Lack of a mitochondria means they must generate ATP anaerobically so they don’t use the oxygen they are transporting to the rest of the body.

Question 15

What is the average life span of a red blood cells

Answer 15

About 120 days

Question 16

Erythropoiesis

Answer 16

The production of red blood cells which occurs in the bone marrow (about 2mil/second)

Erythropoiesis is stimulated by a decrease in oxygen carrying capacity (loss of RBC’s)

Question 17

How are blood cells formed?
(Hematopoiesis)

Answer 17

All blood cells arise from a pluripotent stem cell in red bone marrow which will form 2 stem cell lines:
1. Myeloid stem cells - form RBC’s, platelets, neutrophils, eosinophils, basophils, monocytes
2. Lymphoid stem cells - form lymphocytes

Question 18

What happens to old RBC’s?

Answer 18

• destroyed by macrophages
• hemoglobin is salvaged and turn into heme and globin
• glob in is broken down to amino acids
• heme releases iron which gets stored in the liver
• heme pigment is made into bilirubin

Question 19

Jaundice

Answer 19

Occurs when the liver is not working properly, and bilirubin builds up in the blood and gives a the skin a yellow appearance

Question 20

Anemia

Answer 20

A condition caused by reduced oxygen carrying capacity in blood.
Causes:
1. Decreased number of RBC’s
2. Decreased hemoglobin content (iron deficient)
3. Abnormal hemoglobin

Question 21

Polycythemia

Answer 21

An abnormal increase in the number of RBC’s.
Causes:
1. Bone marrow cancer
2. Occurs naturally when living in high altitudes because of low oxygen context of the air.

Question 22

Sickle cell anemia

Answer 22

Change in amino acid #6 out of a chain of 146 amino acids

Causes hemoglobin to become spiky and sharp, RBC’s become crescent shaped.

Question 23

White blood cells

Answer 23

Function to combat pathogens by using immune responses or phagocytosis (eating invader cells).

They leave the blood stream and collect at sites of inflammation because they are attracted to the chemical stimuli (chemotaxis)

Question 24

Diapedis

Answer 24

The squeezing of the neutrophil through the blood vessel wall in between endothelial cells

Question 25

Platelets

Answer 25

Fragments of cells

Functions in the blood clotting process by forming a platelet plug and release.

(Has no nucleus since its just fragments)

Question 26

Hemostasis

Answer 26

A sequence of events, which stop bleeding when a blood vessel is damaged.

3 steps:
1. Vascular spasm - when injured the damaged vessel constricts and blood flow is reduced.
2. Platelet plug formation - platelets stick to the exposed, collagen fibres. Then the platelets sticky and release chemicals to attract more platelets.
3. Coagulation - a cascade of chemical reactions involving “factors” transform blood into a gel consisting to clot the injury.
≈ 3-6 minutes

Question 27

Clotting factors

Answer 27

13 plasma proteins which circulate in the blood until needed for coagulation

Question 28

Intrinsic pathway to blood clotting

Answer 28

Occurs inside a vessel and is much more complex.

Steps:
1. Collogen fibres get exposed and activates clotting factor XII (12)
2. A series of reactions begin involving CA and PF3 molecules. These will activate clotting factor X (10)
3. Factor 10 will activate prothrombin enzyme which then activates thrombin enzyme.
4. This turns fibrinogen into fibrin which activates factor XIII (13) to clot the injury.

Question 29

Extrinsic pathway to blood clotting

Answer 29

Occurs outside blood vessels, and is much less complex.

Steps:
1. Damage to tissue activates clotting factor III (3) which then can directly activate factor X (10)
2. Factor 10 activates prothrombin which activates thrombin.
3. Fibrinogen turns to fibrin which activates factor XIII (13) to clot.

Question 30

What is the fibrin stabilizing factor?

Answer 30

Clotting factor XIII (13)

It binds all fibre strands together to form a sturdy clot.
The clot plugs the ruptured areas of blood vessels and stops blood loss

Question 31

What happens once a clot has formed?

Answer 31

The clot retracts and the edges of the vessel are pulled closer together to repair. Eventually the clot dissolved once everything is healed.

Question 32

Hemophilia

Answer 32

A bleeding disorder caused by a deficiency of clotting factors.

Can be treated by boosting levels through transfusions.

Question 33

How common are each blood type and RH factor in North America?

Answer 33

Types:
A = 40%
O = 40%
B = 15%
AB = 5%

Rh factors:
Rh+ = 85%
Rh- = 15%

Question 34

How can the Rh factor affect pregnancy?

Answer 34

If a Rh- mother with an Rh+ Fetus, some foetal antigens will enter the mother’s blood during delivery. The mother will produce anti-D antibodies which causes an issue of the next baby is an Rh+. The auntie D antibodies, cross the placenta and can attack baby #2’s RBC’s