[SET 1] 40 The Circulatory System

40.1 Overview of the Circulatory System 40.2 Components of the Blood

What is the primary function of the circulatory system in animals?

To transport nutrients and gases throughout the body and remove waste products.

What is the core component of the human circulatory system?

The heart.

How does the heart contribute to the circulatory system?

It pumps blood throughout the body and is regulated by intrinsic electrical impulses and hormones.

What are the two main types of circulatory systems in animals?

Open and closed circulatory systems.

What distinguishes a closed circulatory system from an open one?

In a closed system, blood is contained within blood vessels, while in an open system, blood (hemolymph) is pumped into a body cavity.

What is hemolymph?

The fluid in an open circulatory system that mixes with interstitial fluid.

What is the role of ostia in an open circulatory system?

Ostia are openings through which hemolymph reenters the heart.

Why do larger and more complex organisms require a circulatory system?

Because diffusion is not efficient for transporting gases, nutrients, and waste across larger body sizes.

What circulatory system do most vertebrates have?

A closed circulatory system.

How do the circulatory systems of fish differ from those of mammals?

Fish have a two-chambered heart and a single circuit for blood flow, while mammals have a four-chambered heart that separates oxygenated and deoxygenated blood.

What is the structure of the heart in amphibians?

Amphibians have a three-chambered heart with two atria and one ventricle.

What circulatory routes do reptiles have?

Reptiles have two circulatory routes but only oxygenate blood through the lungs.

How does the circulatory system of birds differ from that of reptiles?

Birds have a four-chambered heart that completely separates oxygenated and deoxygenated blood.

What is the significance of gas exchange in the circulatory system?

It allows for the transport of oxygen from respiratory organs to tissues and the removal of carbon dioxide.

What is the evolutionary advantage of a closed circulatory system?

It allows for more efficient transport of blood to metabolically active organs and tissues.

What are the components of the blood?

Red blood cells, white blood cells, platelets, and plasma.

What is the role of arteries in the circulatory system?

Arteries carry oxygenated blood away from the heart to the body.

What is the function of veins in the circulatory system?

Veins carry deoxygenated blood back to the heart.

What are capillaries and their function?

Capillaries are small blood vessels where gas and nutrient exchange occurs between blood and tissues.

How does the structure of the heart support its function?

The heart's chambers and valves ensure unidirectional blood flow and efficient pumping.

What is the significance of the rib cage in relation to the heart?

The rib cage protects the heart, which is about the size of a clenched fist.

Why are simple animals like sponges and jellies able to survive without a circulatory system?

They rely on diffusion for gas and nutrient exchange due to their simple body structures.

What evolutionary adaptations have occurred in the circulatory systems of active mollusks like squids?

They have developed a closed circulatory system to support rapid movement and efficient oxygen transport.

What is the impact of body size on the evolution of circulatory systems?

Larger body sizes necessitate more complex circulatory systems to efficiently transport materials.

What are the two circuits of blood flow in amphibians, reptiles, birds, and mammals?

Pulmonary circulation (through the lungs) and systemic circulation (through the rest of the body).

What is pulmocutaneous circulation?

A type of circulation in amphibians where gas exchange occurs through the skin during pulmonary circulation.

How many chambers does an amphibian heart have?

Three chambers: two atria and one ventricle.

What is the disadvantage of the three-chambered heart in amphibians?

It allows for some mixing of oxygenated and deoxygenated blood, reducing oxygenation efficiency.

What adaptation helps reduce blood mixing in the reptilian heart?

A partial septum in the ventricle.

What unique circulatory mechanism do crocodilians have?

They can shunt blood from the lungs to the stomach and other organs during submergence.

What is the foramen of Panizza?

A hole in the heart between the two ventricles of crocodilians that allows blood to move from one side of the heart to the other.

What is the structure of the heart in mammals and birds?

A four-chambered heart with two atria and two ventricles.

What is the advantage of a four-chambered heart?

It separates oxygenated and deoxygenated blood, improving the efficiency of double circulation.

What is convergent evolution in the context of the circulatory system?

The independent evolution of a similar biological trait, such as the four-chambered heart in birds and mammals.

What are the basic components of blood?

Plasma, red blood cells, white blood cells, and platelets.

What is the primary function of hemoglobin?

To carry oxygen and, to a lesser extent, carbon dioxide throughout the circulatory system.

What percentage of blood is made up of cellular components in humans?

Approximately 45 percent.

What role does blood play in maintaining homeostasis?

It stabilizes pH, temperature, osmotic pressure, and eliminates excess heat.

What are the main functions of red blood cells?

To deliver oxygen to cells and remove carbon dioxide.

How are red blood cells formed?

From stem cells in the bone marrow.

What is the size of a typical mammalian red blood cell?

7-8 µm in diameter.

What is unique about the red blood cells of mammals compared to birds and non-avian reptiles?

Mammalian red blood cells are anucleated (lack a nucleus) at maturity.

What is hemocyanin?

A copper-containing protein found in some invertebrates that carries oxygen.

What is the role of platelets in the blood?

To form clots that prevent blood loss after injury.

What is the primary role of white blood cells?

To participate in the immune response.

What is the composition of blood plasma?

Water, proteins, electrolytes, lipids, and glucose.

What is the primary pigment used for oxygen transport in vertebrates?

Hemoglobin.

What is the significance of the large surface area of red blood cells?

It allows for rapid diffusion of oxygen and carbon dioxide across the plasma membrane.

What gas is released in the lungs and taken in by the blood?

Oxygen

What gas is transported back to the lungs from the tissues?

Carbon dioxide

What is the function of nitrous oxide (NO) in the blood?

It is a vasodilator that relaxes blood vessels and aids gas exchange.

How does nitroglycerin help patients with heart conditions?

It is converted to NO to relax blood vessels and increase oxygen flow.

What is the average lifespan of red blood cells?

120 days

What are the two main types of white blood cells?

Granulocytes and agranulocytes

What are the three types of granulocytes?

Neutrophils, eosinophils, and basophils

What is the primary function of white blood cells?

To identify and target pathogens in the immune response.

What do B cells do in the immune system?

They destroy bacteria, inactivate toxins, and produce antibodies.

What is the role of T cells in the immune response?

They attack viruses, fungi, some bacteria, transplanted cells, and cancer cells.

What are platelets and what is their function?

Small cell fragments that help in blood clotting.

What is the process called when blood clots to prevent excess blood loss?

Coagulation

What protein is converted to fibrin during blood clotting?

Fibrinogen

What vitamin is essential for many clotting factors to function?

Vitamin K

What is plasma?

The liquid component of blood that consists of 90% water and various substances.

What is the difference between plasma and serum?

Serum is plasma without the coagulation factors.

What is the most abundant protein in human blood plasma?

Human serum albumin

What are the two most well-known blood groups?

ABO and Rh systems

What antigens are present in blood type A?

Antigen A

What is the universal donor blood type?

Type O negative

What is the universal acceptor blood type?

Type AB positive

What happens when type A and type B blood are mixed?

Agglutination occurs due to antibodies in the plasma.

What can happen if an Rh- person is exposed to Rh+ blood?

They can develop anti-Rh antibodies, leading to a reaction in future exposures.

What is the role of macrophages in the immune system?

They respond to infection or injury by gathering at sites of inflammation.

What is the significance of the HIV virus in relation to T cells?

HIV targets T cells, using their genetic machinery to replicate.

What are the two types of agranulocytes?

Lymphocytes and monocytes

What do natural killer cells do?

They attack a variety of infectious microbes and certain tumor cells.