Lecture 8 - Cardiovascular System and Blood

Cardiovascular system consists of what three components?

The heart (muscular pump), blood vessels (conduits), and blood (fluid)

Which systems most impact cardiovascular function?

Endocrine, nervous, and renal systems

What does blood transport?

Oxygen, carbon dioxide, nutrients, hormones, immune components, and waste products

Why do larger organisms need a circulatory system?

Diffusion alone is too slow over large distances

What is extracellular fluid (ECF)?

Fluid outside cells including plasma and interstitial fluid

What is interstitial fluid?

Fluid surrounding body cells

What is plasma?

The fluid portion of blood

What organisms use choanocytes to move water?

Sponges

What is a gastrovascular cavity?

A cavity used for digestion and distribution of materials

What organisms have open circulatory systems?

Arthropods and most mollusks

What is hemolymph?

Circulatory fluid in open systems that bathes organs directly

What are advantages of a closed circulatory system?

Faster transport and better control of blood flow

What are disadvantages of a closed circulatory system?

Higher energy and maintenance costs

What organisms have closed circulatory systems?

Earthworms, squids, octopi, and vertebrates

What are the two circulatory circuits in birds and mammals?

Pulmonary and systemic circuits

What is the pulmonary circuit?

Blood flow from heart to lungs and back

What is the systemic circuit?

Blood flow from heart to body tissues and back

What do arteries do?

Carry blood away from the heart

What do arterioles do?

Branch from arteries and feed capillaries

What are capillaries?

Sites of exchange between blood and tissues

What do venules do?

Drain capillary beds

What do veins do?

Return blood to the heart

How many chambers does a fish heart have?

Two chambers

What are the chambers of a fish heart?

One atrium and one ventricle

How many chambers does an amphibian heart have?

Three chambers

What are the chambers of an amphibian heart?

Two atria and one ventricle

How many chambers do birds and mammal hearts have?

Four chambers

What are advantages of a four-chambered heart?

Complete separation of oxygenated and deoxygenated blood, efficient oxygen delivery, and different circuit pressures

What are the main purposes of circulation?

Maintain blood pressure, deliver oxygen/nutrients, remove wastes, regulate temperature, distribute hormones, and immune surveillance

Normal blood glucose level?

About 100 mg/dL

Normal mean arterial pressure?

80-100 mmHg

Normal arterial pH?

About 7.38

Normal arterial PO2?

About 100 Torr

Normal plasma osmolality?

About 282 mOsm

Normal core body temperature?

37°C

What are formed elements of blood?

RBCs, WBCs, and platelets

What are erythrocytes?

Red blood cells

What are leukocytes?

White blood cells

What are platelets?

Cell fragments involved in clotting

What percentage of blood volume is plasma?

About 50-60%

What percentage of plasma is water?

More than 90%

What does plasma contain?

Gases, ions, nutrients, proteins, hormones, vitamins, and wastes

What is hematocrit?

The percentage of blood volume made of cells

What are the main functions of RBCs?

Transport oxygen and carbon dioxide

What protein carries oxygen in RBCs?

Hemoglobin

What shape are red blood cells?

Biconcave discs

Why is the biconcave shape important?

Increases surface area for gas exchange

What are rouleaux?

Stacks of RBCs that improve blood flow

What organelles do mature RBCs lack?

Nucleus, DNA, RNA, mitochondria, and ribosomes

How long do RBCs live?

About 120 days

Where are old RBCs removed?

Spleen, liver, and bone marrow

What is erythropoiesis?

Production of red blood cells

Where does erythropoiesis occur in adults?

Red bone marrow

What hormone stimulates RBC production?

Erythropoietin (EPO)

Where is EPO produced?

Kidneys

What stimulates EPO release?

Low oxygen levels (hypoxia)

What materials are needed for RBC production?

Amino acids, iron, vitamin B12, vitamin B6, and folic acid

What is pernicious anemia?

Low RBC production due to vitamin B12 deficiency

What is hemoglobin made of?

Four globin subunits with four heme groups containing iron

How many oxygen molecules can one hemoglobin bind?

Four

What is oxyhemoglobin?

Hemoglobin bound to oxygen

What is deoxyhemoglobin?

Hemoglobin not bound to oxygen

What is carbaminohemoglobin?

Hemoglobin bound to carbon dioxide

What happens to hemoglobin in high PO2 environments?

It binds oxygen

What happens to hemoglobin in low PO2 environments?

It releases oxygen

What is positive cooperativity in hemoglobin?

Binding of one oxygen increases affinity for more oxygen

What shape is the oxygen dissociation curve?

Sigmoidal (S-shaped)

What is the Bohr effect?

Low pH decreases hemoglobin's affinity for oxygen

What does 2,3-BPG do?

Lowers hemoglobin affinity for oxygen

What is myoglobin?

An oxygen-binding protein in muscle

How does myoglobin differ from hemoglobin?

Myoglobin has higher oxygen affinity and binds one oxygen molecule

How is most CO2 transported in blood?

As bicarbonate ions (HCO3-)

What enzyme converts CO2 into bicarbonate?

Carbonic anhydrase

What is the bicarbonate reaction?

CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3-

What conditions can decrease oxygen delivery?

Hypoxia, anemia, hemorrhage, poor diet, sickle cell disease, and kidney disease

What determines blood type?

Presence or absence of A, B, and Rh antigens on RBCs

What antigens are present in type A blood?

A antigens

What antibodies are present in type A blood?

Anti-B antibodies

What antigens are present in type B blood?

B antigens

What antibodies are present in type B blood?

Anti-A antibodies

What antigens are present in type AB blood?

Both A and B antigens

What antibodies are present in type AB blood?

Neither anti-A nor anti-B antibodies

What antigens are present in type O blood?

Neither A nor B antigens

What antibodies are present in type O blood?

Both anti-A and anti-B antibodies

What does agglutination mean?

Clumping of RBCs due to antigen-antibody reactions

What is a transfusion reaction?

A dangerous antigen-antibody reaction between incompatible blood types

What is the Rh factor?

The D antigen on RBCs

What does Rh positive mean?

The D antigen is present

What does Rh negative mean?

The D antigen is absent

What is anemia?

A decrease in the oxygen-carrying capacity of blood

What is iron-deficiency anemia?

Anemia caused by insufficient iron

What is hemorrhagic anemia?

Anemia caused by blood loss

What is hemolytic anemia?

Anemia caused by destruction of RBCs

What is aplastic anemia?

Anemia caused by bone marrow failure

What is renal anemia?

Anemia caused by kidney disease and low EPO

Why can EPO abuse be dangerous?

It increases blood viscosity and risk of clotting, stroke, and heart failure

What does the spleen do with old RBCs?

Removes and breaks them down

What happens to iron from destroyed RBCs?

It is recycled

What is bilirubin?

A breakdown product of heme

Where is bilirubin processed?

The liver