BIOL 1410 L13: Blood, Lymph and the Lymphatic System

What contains extracellular fluid?

Lumen

Primary types of extracellular fluids (3)

1. Interstitial fluid

2. Blood plasma

3. Lymph

Interstitial fluid

Extracellular fluid that surrounds all cells except blood cells

Blood plasma

Extracellular fluid that surrounds blood cells

Lymph

Extracellular fluid found within lymph vessels that form a component of the lymphatic system

Blood is composed of (2)

• Cells (red and white)

• Plasma

Which has a higher viscosity - blood or water?

Blood

How much blood does an adult human have?

4-6 liters

Blood pH range

7.35-7.45

Temperature of blood

38 degrees C

Why is blood temperature slightly higher than body temperature?

It is always moving and producing heat

Is hemoglobin extra- or intracellular?

Intracellular

Plasma composition breakdown (%)

• 90% water

• 8% protein

• 2% other solutes

Proteins found in plasma (3)

Albumin, fibrinogen, and globulins

Other solutes found in plasma (4)

Gases, ions, nutrients, and hormones

Formed elements

Red blood cells, white blood cells and platelets

Red blood cells also known as

Erythrocytes

Do red blood cells have a nucleus?

No, they lose it once they reach maturity - become anuclear

Losing the nucleus of the red blood cell decreases what?

Lifespan of the cell - 120 days until broken down by the spleen

Where are red blood cells produced?

Red bone marrow of adults (ribs and sternum)

How many red blood cells per mm3 of blood?

4.3-5.8 million

Where are large quantities of hemoglobin located?

Red blood cells

Hemoglobin composition

Heme and 4 protein chains (globin chains)

Heme component is responsible for what?

Pigmented; characteristic red color of blood

What does a heme contain?

Iron

How do oxygen molecules bind to the hemoglobin?

Iron inside of the heme bind to oxygen and transport the gas throughout the body

What happens to the iron and heme when red blood cells are broken down?

Iron - recycled for reuse

Heme - converted into bilirubin

Bilirubin

Component of bile (synthesized in liver, stored in gallbladder, aid digestion)

Iron is always attached to what? Why?

A carrier protein; free iron is toxic

How much of CO2 is transported throughout the blood?

20% - rest use alternative methods

Hematocrit

The percentage of blood volume that is red blood cells

Normal hematrocrit value

40%

Which is larger - red or white blood cells?

White blood cells

Function of white blood cells

Fight off infection

Lifespan of white blood cells

Live for many years

How many white blood cells per mm3 of blood?

5000-10,000 - dramatically increase during periods of infection

Two classes of white blood cells

1. Granulocytes

2. Agranulocytes

Types of granulocytes (3)

B.E.N.

1. Basophils

2. Eosinophils

3. Neutrophils

Neutrophils function

As phagocytes - key immune cells

How much do neutrophils account for all WBC

60%

Eosinophils function

Destroy parasites and control inflammation by turning off inflammatory mediators

Eosinophils complexes

Phagocytize antigen-antibody (phagocytosis)

How much do eosinophils account for all WBC

2.4%

What does basophils produce and their functions? (2)

• Histamine → give symptoms of allergy → stimulate inflammation

• Heparin → decrease blood clotting

How much do basophils account for all WBC?

0-1%

Types of agranulocytes (2)

1. Lymphocytes

2. Monocytes

How much do lymphocytes account for all WBC?

20-25%

Lymphocytes function

Responsible for adaptive immunity → very specific immune responses

Types of lymphocytes (2)

1. T lymphocytes

2. B lymphocytes

T lymphocytes function

Responsible for the activation of the immune response and the killing of infected host cells

B lymphocytes function

Develop into plasma cells that produce and secrete immunoglobulins (antibodies)

What are monocytes called when matured?

Macrophages

Where are macrophages present?

In tissue → NOT found in the blood

What cells are professional phagocytes?

Monocytes

How much do monocytes account for all WBC?

4-8%

Key players in the formation of blood clots

Platelets

How are platelets produced?

From the fragmentation of megakaryocytes

Lifespan of platelets

5-10 days - has nothing to keep it living like a nucleus

How many platelets per mm3 of blood?

250,000-500,000

Hematopoiesis

The generation of all formed elements present in the blood

Hemocytoblasts

Hematopoietic stem cells located in the red bone marrow

Where is red bone marrow located in adults?

In the axial skeleton, proximal ends of the humerus and femur, and the pectoral and pelvic girdle

Process from hemocytoblasts to RBCs

Hemocytoblasts → reticulocytes → red blood cells

Lymphatic system function

Bodily defense against infection

What is the lymphatic system composed of?

1. Lymph

2. Lymphatic organs and tissues

3. Lymphatic vessels and capillaries

Lymph is formed from what?

Interstitial fluid → similar to the consistency of plasma

How much of interstitial fluid reenters the blood?

90%

How much of interstitial fluid enters into the lymphatic system?

10%

What does it mean that lymphatic capillaries are blind ended?

The vessels end in a closed or one-way configuration

Process of how interstitial fluid enters the lymphatic system? (3)

1. Enters lymphatic capillaries

2. Drain into collecting tubules (thin walled and contain valves)

3. Lymph flows unidirectionally (away from the tissues)

Circulation of lymph is facilitated by (4)

• Skeletal muscle movement

• Valves in the vessels to prevent backflow

• Pressure changes during breathing

• Smooth muscle contractions in the walls of the lymphatic vessels

Where are lymph nodes located?

At various spots along the length of the collecting vessels

Lymph function

Filters the lymph that passes by, removing any microorganisms (bacteria, parasites, fungi), viruses or debris that might be present

Lymphatic vessels lead into either (2)

1. Right lymphatic duct

2. Thoracic lymphatic duct

Right lymphatic duct (2)

Dumps lymph into the right subclavian vein; Entry point for lymph that is coming anywhere EXCEPT the lower half of body

Thoracic duct (3)

Dumps lymph into the left subclavian vein; Duct begins as the cisterna chyli (abdomen); Entry point for lymph from the lower half of the body

Two classes of lymphatic organs

1. Primary

2. Secondary

Primary lymphatic organs and tissues (2)

1. Red bone marrow

2. Thymus

What takes place in red bone marrow in adults?

B lymphocyte proliferation and maturation

What originates in bone marrow of developing fetus?

T and B lymphocytes

What takes place in the thymus of adults?

T lymphocyte proliferation and maturation

Secondary lymphatic organs and tissues (3)

1. Spleen

2. Tonsils

3. Lymph nodes

Site of T and B lymphocyte proliferation

Spleen

Spleen function

Filters blood and destroys old RBCs, bacteria and toxins

Types of tonsils (3)

1. Palatine tonsils

2. Pharyngeal tonsils

3. Lingual tonsils

What type of tonsils are commonly removed?

Palatine tonsils

Where are palatine tonsils located?

2 located in the oropharynx

Term for when pharyngeal tonsils are enlarged

Adenoids

Where is the pharyngeal tonsil located?

1 located in the nasopharynx

Where are lingual tonsils located?

2 located at the base of the tongue

Types of lymph nodes and their locations (4)

1. Axillary - under arms

2. Cervical - neck

3. Inguinal - groin area

4. Pelvic - abdominal area

What happens when lymph nodes activate?

T and B lymphocytes proliferate mitotically within the lymph node