Ch 44

Question 1

What are the components of a circulatory system?

Answer 1

circulating fluid (ex:blood), a pump (heart), and vessels or spaces to hold the fluid

Question 2

What are the two types of circulatory systems?

Answer 2

an open circulatory system: the circulating fluid leaves vessels to directly come in contact with tissue cells, closed system: the circulating fluid is always contained in vessels

Question 3

characteristics of an open circulatory system

Answer 3

found in some mollusks and most arthropods including insects, the interstitial fluid and circulating fluid are one and same (hemolymph), a peristaltic heart produces low pressure, the fluid slowly percolates through the body in large sinuses or a hemocoel (slow delivery limits oxygen transport, active insects have separate tracheal system for O2 and colorless blood (no respiratory pigment, some mollusks and arthropods contain hemocyanin)

Question 4

characteristics of a closed circulatory system

Answer 4

found in some invertebrates and all vertebrates, there are two fluids: interstitial fluid (which becomes lymph) and blood, in the vertebrates a chambered heart produces high pressure, blood is always contained in a system of tubes or pipes

Question 5

functions of the vertebrate circulatory system

Answer 5

carry nutrients from digestive system to cells, carry oxygen from respiratory system to cells, carry metabolic wastes to excretory organs (carbon dioxide to respiratory surface and other wastes to liver and kidneys), afferent and efferent pathways for hormones, maintain fluid balance, defense, distribution of body heat

Question 6

what two things is blood made up of?

Answer 6

plasma and cells

Question 7

What is the ratio of plasma to cells?

Answer 7

55 plasma to 45 cells

Question 8

What is blood comprised of? (Including percentages)

Answer 8

plasma is 55% of blood, water is 92% of plasma and proteings are 7% of plasma, cells are 45% of blood

Question 9

What are the different types of blood cells?

Answer 9

leukocytes, erythrocytes, thrombocytes

Question 10

What is plasma made up of? (including percentages)

Answer 10

92% water, 7% proteins (these proteins include albumins, globulins, and figrinogen), and various salts, gases, hormones, nutrients, and wastes

Question 11

What are the blood’s cells made up of?

Answer 11

95% red blood cells, 4% platelets, and <1% white blood cells

Question 12

What are the two types of leukocytes and what are some examples of each?

Answer 12

granular: neutrophils (phagocytic), eosinophils (allergic responses and some infections), basophils (release histamine and some infections), and agranular: lymphocytes (antibodies), and monocytes (macrophages)

Question 13

What are thrombocytes?

Answer 13

platelets

Question 14

What are erythrocytes?

Answer 14

red blood cells

Question 15

How does blood clot? (the process)

Answer 15

Injury to the blood vessel, the injured vessel then constricts to reduce blood loss, platelets physically patch the break by sticking to the rough, cut edges of the vessel, as the platelets begin to gather the release substances that attract other platelets, the platelets become sticky and adhere to collagen fibers in the blood vessel wall, within about 5 minutes after injury they form a platelet plug, or a temporary clot, at the same time that the temporary clot forms, a stronger, more permanent clot begins to develop, more than 30 chemical substances interact in this complex process, the series of reactions that leads to clotting is triggered when one of the clotting factors in the blood is activated by contact with the injured tissue, prothrombin, a plasma protein manufactured in the liver, requires vitamin K for its production, in the presence of clotting factors, calcium ions, and compounds released from platelets, prothrombin is converted to thrombin, then thrombin catalyzes the conversion of the soluble plasma protein fibrinogen to an insoluble protein, fibren, once formed, fibrin polymerizes, producing long threads that stick to the damaged surface of the blood vessel and form the webbing of the clot, these threads trap blood cells and platelets which help strengthen the clot

Question 16

What is the function of neutrophils? Eosinophils? Basophils? Lymphocytes? Monocytes?

Answer 16

phagocytosis; allergic responses and immune responses; prevention of inappropriate clotting; produce antibodies and destroy foreign cells; can differentiate to form macrophages and dendritic cells

Question 17

What is the function of red blood cells? Platelets?

Answer 17

oxygen transport and carbon dioxide transport; essential for clotting

Question 18

What do arteries do? What are the layers in the arteries?

Answer 18

Arteries provide elasticity, Tunica intima (INtima-inside of the artery): endothelium, tunica media (MEDia-middle layer): connective tissue and smooth muscle, tunica adventitia (outer layer): connective tissue with collagen

Question 19

arterioles

Answer 19

provide resistance, arterioles are smaller arteries

Question 20

capillaries

Answer 20

provide for exchange (single layer of endothelium and a basement membrane), the smallest, thin-walled exchange vessels through which blood and tissues exchange materials

Question 21

What do veins and venules do?

Answer 21

they provide capacitance, which is space for the rest of the fluid, venules are smaller versions of veins much like arterioles are smaller versions of arteries

Question 22

What do lymphatic capillaries and vessels do?

Answer 22

drain interstitial fluid

Question 23

Can veins be closed off?

Answer 23

Yes, if their blood tries to move the wrong way valves can close them off

Question 24

Arteries

Answer 24

carry blood AWAY from the heart

Question 25

Veins

Answer 25

return blood to the heart

Question 26

What is vasoconstriction? Vasodilation?

Answer 26

vasoconstriction is when arterioles constrict, vasodilation is when arterioles dilate, they do this to regulate blood pressure and the distribution of blood to the tissues

Question 27

When are metarterioles used?

Answer 27

when muscles don’t need more blood because they’re not in use so the blood doesn’t need to be pumped through the capillaries, metarterioles directly link arterioles with venules

Question 28

Do atria recieve blood or pump it? Ventricles?

Answer 28

Atria recieve blood, ventricles pump blood into the arteries

Question 29

What animal is the only vertebrate with a single circuit system?

Answer 29

Fish, they have a 2 chambered heart with 1 atrium and 1 ventricle

Question 30

What do reptiles have for a cardiovascular system that differs from mammals?

Answer 30

the reptilian heart has two atria and two ventricles, in most reptiles the wall separating the ventricles in incomplete so blood from the right and left chambers mixes to some extent, in crocodiles and alligators the septum is complete and the heart consists of four separate chambers

Question 31

What do amphibians have for a cardiovascular system?

Answer 31

in amphibians, the heart consists of two atria and one ventricle, blood flows through a double circuit

Question 32

What do birds and mammals have for a cardiovascular system?

Answer 32

in birds and mammals, the two atria and two ventricles separate oxygen-rich blood from oxygen-poor blood

Question 33

What is the pattern of blood circulation in birds and mammals?

Answer 33

veins (conduct blood from organs)->right atrium->right ventricle->pulmonary arteries->capillaries in the lungs->pulmonary veins->left atrium->left ventricle->aorta->arteries (conduct blood to organs)->arterioles->capillaries->veins

Question 34

Which side has oxygenated blood, left or right?

Answer 34

Left has oxygenated blood, right has deoxygenated

Question 35

In the human heart there are 4 valves that prevent the backflow of blood. What are they and where are they?

Answer 35

The right atrioventricular valve (tricuspid valve): between the right atrium and ventricle, left atrioventricular valve (bicuspid valve): between the left atrium and ventricle, semilunar valves (two of them): aortic valve is between the left ventricle and the aorta, and the pulmonary valve is between the right ventricle and the pulmonary artery

Question 36

Explain how each heartbeat is initiated by a ‘pacemaker’

Answer 36

the cardiac muscle fibers are joined by intercalated discs which are dense bands at the ends of cardiac muscle cells, these complex junctions contain gap junctions which make it easy for action potentials to occur, this allows ions to move easily through the gap junctions, allowing the entire atrial muscle mass to contract as one giant cell, the sinoatrial (SA) node, or the ‘pacemaker’ ensures that the heart beats in a regular and effective rhythm

Question 37

Cardiac cycle

Answer 37

the cardiac cycle is what occurs during one complete heartbeat, during this heartbeat there is a period of contraction (systole) and a period of relaxation (diastole), during systole the “lub” sound is made which comes from the closing of the AV valves (both bicuspid and tricuspid), during diastole, you hear the “dub” sound which is the closing of the semilunar valves (both aortic and pulmonary)

Question 38

blood pressure

Answer 38

blood pressure is the force that blood exerts against the inner walls of the blood vessel, it is greatest in the arteries and decreases as blood flows through the capillaries, blood pressure depends on how much blood you have (blood volume), how fast you’re trying to move it (cardiac output), and how much your blood sticks against vessels and how much the blood is slowed (peripheral resistance)

Question 39

What does blood pressure depend upon?

Answer 39

blood pressure depends on how much blood you have (blood volume), how fast you’re trying to move it (cardiac output), and how much your blood sticks against vessels and how much the blood is slowed (peripheral resistance)

Question 40

What is blood viscosity?

Answer 40

how thick/watery the blood is

Question 41

What is peripheral resistance? What does it depend upon?

Answer 41

peripheral resistance is the resistance to blood flow in the body, it depends upon blood viscosity and the friction between blood and the blood vessel wall

Question 42

How is heart rate regulated?

Answer 42

it is regulated mainly by the nervous system, it’s influenced by hormones and body temperature

Question 43

How is cardiac output calculated?

Answer 43

stroke volume times heart rate (stroke volume depends on venous return and on neural messages and hormones, especially epinephrine and norepinephrine)

Question 44

How is blood pressure calculated?

Answer 44

blood flow times peripheral resistance

Question 45

What are baroreceptors?

Answer 45

specialized receptors in the walls of certain arteries and in the heart wall, they are sensitive to changes in blood pressure, when an increase in blood pressure stretches the baroreceptors messages are sent to the cardiac and vasomotor centers in the medulla of the brain

Question 46

What happens when blood pressure increases?

Answer 46

the cardiac center stimulates parasympathetic nerves that slow heart rate, vasomotor center inhibits sympathetic nerves that constrict blood vessels, blood pressure is thus reduced

Question 47

What is angiotensin?

Answer 47

it is a vasoconstrictor, a hormone that raises blood (angioTENSin-tensed blood vessels increase blood pressure)

Question 48

What is aldosterone?

Answer 48

it helps regulate salt excretion which affects blood volume and blood pressure, we expel a lot of salt (pee) and lose a lot of water doing this which is what blood is mainly made of so it reduces blood volume and therefore the blood pressure

Question 49

What does the lymphatic system do?

Answer 49

collects interstitial fluid and returns it to the blood, plays an important role in homeostasis of fluids, defends the body against disease by transporting white blood cells, absorbs lipids from digestive tract

Question 50

lymphatic vessels

Answer 50

conduct lymph to the thoracic duct and right lymphatic duct in the shoulder region, ducts return lymph to the blood circulatory system