The blood, lecture content

What is the heart made up of?

Blood vessels and a double pump conducting system (pulmonary and systemic flow)

What is blood?

The fluid medium of the cardiovascular system

What is the extracellular matrix of blood?

Plasma and formed elements

What are the functions of blood?

• Gas exchange (O2 from lungs to tissues via RBC, CO2 away from tissues to the lungs)

• Distributing solutes like nutrients, hormones, and wasted

• Immunity with leukocytes

• Maintenance of body temperature, the blood carries heat produced by catabolic reactions away from tissues

• Seals damaged blood vessels with clots

• Ph homeostasis

• Stabilized blood pressure with blood volume

Where are plasma proteins found?

In the blood, they are too big to dissolve exit the bloodstream

What determines the viscosity of blood?

Water in plasma

Where is albumin made? What does it do?

It's made by the liver, it draws water into the blood via osmosis (osmotic pressure), it also transports hormones

What are y-globulins? Where are they made?

They are antibodies made by leukocytes

What are alpha, beta, and lipoproteins? What do they do?

They are globular transport proteins that transport lipid based compounds

What solutes are found in the blood? How are they transported

Glucose, amino acids, nitrogenous wasted, ions, gases like oxygen and carbon dioxide are transported in the capillaries

What is blood volumne? Literally the percentage and number of liters

7%, 5 liters

What are the general characteristics of blood?

A high viscosity due to the formed elements and plasma, a slightly basic pH

What is the structure of erythrocytes?

They have a bi-concave disc and a large surface to volume ratio that is critical for gas exchange, they also lack mitochondria and a nucleus

What is the structure of hemoglobin?

It is a large protein with 4 polypeptide subunits, 2 alpha chains, 2 beta chains, and a heme group

What does the heme group do where oxygen is high?

In the lungs it binds to oxygen, forming oxyhemoglobin (HbO2)

What is the difference between where the hemegroup binds to o2 and co2

oxygen binds to the subunit, co2 binds outside it

What does the heme group do when oxygen is low?

In the tissues surrounding the systemic capillaries, it releases oxygen to become deoxyhemoglobin

What does hemoglobin bound to Co2 form?

Carbaminohemoglobin

What is oxygen bound to carbon monoxide called?

carboxyhemoglobin

Does blood bind more easily to carbon dioxide or carbon monoxide?

Carbon monoxide

What is the difference between plasma and interstial fluid?

Plasma has proteins

What is the lifespan of erythrocytes and why?

They have a short life span of 100-120 days, they are constantly under pressure but cannot make repairs

Where does hematopoiesis occur?

In red bone marrow

What does red bone marrow house?

Hematopoietic stem cells that creates all formed elements

Describe the steps of erythropoiesis

Hematopoietic stem cells → erythrocyte colony forming units that are committed → proerythroblast → early erythroblast that makes hemoglobin, a later forming one shrinks and ejects organelles and nucleus → reticulocytes/band cells enter the blood → erythrocytes

How do reticulocytes exit the blood stream?

They use exocytosis to squeeze through the pores in the sinusoidal capillaries of bone marrow

How long does erythropoiesis take?

5-7 days

What happens when hematocrit is low?

Not enough erythrocytes will be available to transport oxygen

What happens if the hematocrit climbs too high?

Blood thickness/viscosity increases

What increases the rate of erythrocyte production?

Growth factors and erythropoietin secretion

What does erythrocyte death entail?

Macrophages of the liver, spleen, or bone marrow break them down and recycle them to make new hemoglobin in red bone marrow. They monitor RBC and eat them before they rupture (hemolyosis) to prevent hemoglobin and iron from entering the blood

What is hemoglobin broken down into?

biliverdin (green, like vermillion first), then bilirubin (yellow, excreted in liver), also broken down into amino acids and ions

What are erythrocytes made of?

Amino acids, iron, vitamins B12, B6, and follic acid

What can anemia be caused by?

decreased or abnormal hemoglobin , decreased hematocrit

What are the symptoms of anemia?

Fatigue, weakness, insomnia, parllor, and shortness of breath

What is chemotaxis?

When leukocytes are attracted to chemical stimuli