Chapter 47 Circulatory System Part 2

Question 1

Hematocrit

Answer 1

The volume of blood that is composed of red blood cells, usually between 40 and 65% in vertebrates.

Question 2

Hemoglobin

Answer 2

An iron-containing protein that binds oxygen and is found within the cytosol of red blood cells.

Question 3

Anemia

Answer 3

A condition characterized by lower than normal levels of hemoglobin, which reduces the amount of oxygen that can be stored in the blood.

Question 4

Platelets

Answer 4

Cell fragments in the blood of mammals that play a crucial role in the formation of blood clots.

Question 5

Thrombocytes

Answer 5

Intact cell in the blood of vertebrates other than mammals that plays a crucial role in the formation of blood clots; in mammals, cell fragments called platelets serve this function.

Question 6

Fibrin

Answer 6

A protein that forms a meshwork of threadlike fibers that wrap around and between platelets and blood cells, enlarging and thickening a blood clot.

Question 7

Stroke Volume

Answer 7

The amount of blood ejected with each beat, or stroke, of the heart.

Question 8

Vasodilation

Answer 8

An increase in blood vessel radius; an important mechanism for directing blood flow to specific regions of the body.

Question 9

Vasoconstriction

Answer 9

A decrease in blood vessel radius; an important mechanism for directing blood flow away from specific regions of the body.

Question 10

Resistance

Answer 10

The tendency of blood vessels to slow down the flow of blood through their lumens.

Question 11

Thrombocytes

Answer 11

Intact cell in the blood of vertebrates other than mammals that plays a crucial role in the formation of blood clost; in mammals, cell fragments called platelets serve this function.

Question 12

Diastole

Answer 12

The phase of the cardiac cycle in which the ventricles fill with blood coming from the atria through the open AV valves.

Question 13

Systole

Answer 13

The second phase of the cardiac cycle, in which the ventricles contract and eject the blood through the open semilunar valves.

Question 14

Open Circulatory System–describe and purpose

Answer 14

The heart or hearts pump hemolymph through vessels into a body cavity called a hemocoel. The nutrients in the hemolymph are absorbed by the tissues. It is especially good at adjusting to need differences in metabolism in an inexpensive manner. If a bug flaps its wings, hemolymph will be pumped to the wing area due to the mechanical motion of the wings.

Question 15

Closed Circulatory System–describe and purpose

Answer 15

Shared key features include: Blood, blood vessels, Immune cells within blood, and the clirculatory system can adjust to metabolic demands, clotting of blood for healing, the body can control where blood goes—the stomach or skin, and it allows the animal to grow larger because of the efficiency of the network to get blood where it is needed?

Question 16

Single Circulation

Answer 16

Fish—There is a single filling chamber or atrium, and an exit chamber or ventricle. Blood is directed to the gills where is absorbs oxygen, and the blood then moves to the rest of the body. This system is ideal in a low pressure situation. Not much pressure is needed to oxygenate the blood nor get it to the rest of the body.

Question 17

Intermediate Circulation

Answer 17

Amphibians and Reptiles—The heart has two atria for collecting blood. One for blood from the heart and one for the lungs. Then there is one ventricle to send the blood to the lungs and body. This is setup so that the frog can depend on the lungs for oxygen exchange when on land and skin for when it is in the water.

Question 18

Double Circulation

Answer 18

Crocodiles, Birds, and Mammals—There are two distinct pathways for blood to travel. One atrium and ventricle send blood to be oxygenated in the lungs. The other atrium and ventricle collect blood from the lungs and sends it to the rest of the body. This allows the two ventricles to function as if they were two hearts. The low pressure is for the lungs, and the high pressure is for the body.

Question 19

List and describe the 4 components of blood

Answer 19

Plasma—35—60% of blood is composed of plasma. It has water and dissolved organic and inorganic nutrients were ingested. It contains dissolved oxygen; waste products of metabolism, and others. Plasma also has buffers to maintain the body’s pH.
Leukocytes—White blood cells develop in bone marrow to fight infection and disease.
Erythrocytes—Red blood cells transport oxygen through the body. Developed in the bone marrow, the red blood cells are 10 times more numerous than leukocytes. There is no nucleus and a biconcave disc shape.
Platelets—cell fragments that lack a nucleus. These fragments bind to form blood clots at the site of injury. Formed in the bone marrow.

Question 20

Describe the vertebrate heart

Answer 20

There are two distinct pathways for blood to travel. One atrium and ventricle send blood to be oxygenated in the lungs. The other atrium and ventricle collect blood from the lungs and sends it to the rest of the body. This allows the two ventricles to function as if they were two hearts. The low pressure is for the lungs, and the high pressure is for the body. Vertebrates also have myogenic hearts that contain pacemakers within the organ to make the heart beat. There are two distinct pathways for blood to travel. One atrium and ventricle send blood to be oxygenated in the lungs. The other atrium and ventricle collect blood from the lungs and sends it to the rest of the body. This allows the two ventricles to function as if they were two hearts. The low pressure is for the lungs, and the high pressure is for the body. Vertebrates also have myogenic hearts that contain pacemakers within the organ to make the heart beat.

Question 21

Describe blood vessels and their purpose.

Answer 21

Blood vessels are tubes that send blood from the heart to the organs. There are arteries, arterioles, and cappilaries, each of diminishing size. There are also veins that take the blood back to the heart to be reoxygenated.

Question 22

What is the relationship between blood pressure, blood flow, and resistance?

Answer 22

Resistance is the tendency of blood vessels to slow down the flow of blood through their lumens. Flow is the change of pressure divided by the resistance. As the vessels get smaller, the resistance increases. As the blood has a higher hematocrit level, the blood slows down. The dilation of a vessel can be controlled by the smooth muscle in the vessel walls.

Question 23

Compare and contract a myogenic heart with a neurogenic heart. which do humans have?

Answer 23

Both hearts beat and send fluid to be oxygenated so that fluid will oxygenate tissue.
The Neurogenic heart has to receive a constant signal from the CNS in order to maintain a pulse.
The Myogenic heart has its own pacemaker within the arteriole walls and will beat on its own without the CNS. The CNS still has some control over how often the heart beats. Humans are Myogenic

Question 24

What is the difference between single circulation and double circulation?

Answer 24

In single circulation, the heart pushes blood to the lungs which directly goes to the tissues. One single pressure throughout the whole body.
In a double circulation, the heart pushes blood to the lungs. The lungs send the blood back to the heart. The heart then sends the blood throughout the rest of the body. Double circulation acts as a double pressure system.