Unit 1 Study Guides (Chapters 18-20)

Question 1

The right side of the heart furnishes blood to what circuit? Where does it carry the blood to and from? Is the blood oxygenated, deoxygenated or both? It pumps the blood into what trunk? Is the blood in that vessel oxygenated or deoxygenated? What does this trunk divide into?

Answer 1

Right side receives deoxygenated blood through the superior and inferior vena cava, then leaves via pulmonary trunk, which branches into the left and right pulmonary arteries (pulmonary circuit)

Question 2

The left side supplies blood to what circuit, and where does this circuit carry blood to? Is the blood oxygenated, deoxygenated or both? It receives blood from what vessels? It pumps blood into what vessel? Is the blood in that vessel oxygenated or deoxygenated?

Answer 2

The left side receives oxygenated blood via the pulmonary veins and leaves through the aorta (systemic circuit) and goes to the rest of the body.

Question 3

What is the pericardium? The pericardial sac has how many layers?
Which is the tough fibrous layer? Is it superficial or deep? What is the name of the thin serous layer? Is it superficial or deep? The serous membrane covering the heart is also known by what two names?

Answer 3

1) Pericardium: double-walled sac around the heart
2) Pericardial sac has 2 layers:
-Superficial fibrous layer of connective tissue (fibrous layer)
-Deep, thin serous layer (parietal pericardium) (aka visceral pericardium aka epicardium)

Question 4

Where is the pericardial cavity and what does it contain? What is the function of this fluid?

Answer 4

Pericardial cavity: a space below the pericardial sac filled with 5 to 30 mL of pericardial fluid; serous membrane makes the fluid. It lubricates the layers of the heart

Question 5

1) What isolates the heart from other thoracic organs and allows it room to expand, without overfilling?
2) What is inflammation of the membranes?

Answer 5

1) The pericardium
2) Pericarditis is painful inflammation of the membranes

Question 6

The heart wall consists of three layers, what are those three layers?

Answer 6

Epicardium,myocardium, endocardium

Question 7

The ______________ (visceral pericardium) is a serous membrane on the heart surface.

Answer 7

epicardium

Question 8

What coronary blood vessels travel through the epicardium?

Answer 8

The largest branches of coronary blood vessels travel through the epicardium.

Question 9

What lines the interior of the heart chambers?

Answer 9

The endocardium

Question 10

What is the middle layer of the heart called and what is composed of? What is this layer responsible for?

Answer 10

1) Myocardium has cardiac muscle as well as a fibrous skeleton framework of collagenous and elastic fibers
2) Responsible for the muscle that spirals around the heart (produces wringing motion)

Question 11

1) Which side of the heart’s myocardium has more muscle and why?
2) The fibrous skeleton of the myocardium has multiple functions, what are some of these functions?

Answer 11

1) The left side has more muscle because the number of layers of cardiac muscle is proportional to workload
2) Functions of the fibrous skeleton of the myocardium:
-Provides structural support and attachment for muscle and valves
-Electrical insulation between atria and ventricles (limits spread of action potentials)

Question 12

The heart has how many chambers? How would you describe them and what is their function?

Answer 12

1) The heart has 4 chambers
2)
The atria are the top two smaller thin-walled chambers, their function is to pump blood into the ventricles
The ventricles are the larger bottom two chambers, and they have thicker walls, and their function is to pump blood into blood vessels

Question 13

Why are the atria called receiving chambers? Which veins empty into each atria?

Answer 13

1) The atria are called the receiving chambers because they are the first chamber the blood enters when it gets to the heart
2) The right atrium receives blood from the superior and inferior vena cavae, and the left atrium receives blood from the pulmonary veins.

Question 14

What is the pectinate muscle? What are the auricles, where are they found, and what is their purpose?

Answer 14

1) The pectinate muscle is the internal ridges of atria and auricles
2) Auricles can be seen on the surface of the heart on the atria, and they are used to enlarge the atria.

Question 15

1) The inferior chambers, are named what?
2) What do they do? Why are they described as discharging chambers?

Answer 15

1) The left and right ventricles
2) They’re the discharging chambers of the heart, meaning that when they contract, they push blood from their chambers to the outside of the heart

Question 16

1) What are the trabeculae carneae and what is their purpose?
2) Which arteries do the ventricles empty into?

Answer 16

1) The trabeculae carneae are internal ridges in both ventricles; they prevent the heart from suctioning itself together.
2) The left ventricle empties into the aorta, and the right ventricle empties into the pulmonary artery.

Question 17

1) What chambers do the atrioventricular sulcus separate?
2) What chambers do the interventricular sulcus separate?

Answer 17

1) The atrioventricular sulcus separates the atria and ventricles
2) The interventricular sulcus overlies the interventricular septum that separates the left and right ventricles

Question 18

What blood vessels are contained within the sulci of the heart?

Answer 18

Both sulci contain coronary arteries

Question 19

1) What is the interatrial septum and what does it divide?
2) What is the name of the hole in the fetal interatrial septum?

Answer 19

1) The interatrial septum is a wall that separates the left and right atria
2) Foramen ovale is the hole in the fetal interatrial septum

Question 20

What is the interventricular septum, and what does it divide?

Answer 20

The interventricular septum is the muscle that separates the left and right ventricles

Question 21

1) What do the valves of the heart ensure?
2) Valves lie between which chambers?
3) The atrioventricular (AV) valves regulate the openings between what?

Answer 21

1) The valves of the heart ensure the one-way flow of blood.
2) Valves lie between the atria and ventricles, and the heart and the exterior
3) The AV valves regulate the openings between the atria and ventricles

Question 22

1) What is the right AV valve also known as, and how many cusps does it have?
2) What is the left AV valve also known as, and how many cusps does it have?

Answer 22

1) The right AV valve is also known as the tricuspid valve; 3 cusps
2) The left AV valve is also known as the bicuspid or mitral valve; 2 cusps.

Question 23

What are the chordae tendineae and what is their function? What muscle do they connect the AV valves to? What do they prevent from happening?

Answer 23

The chordae tendineae connect the AV valves to the papillary muscles; they prevent the AV valves from flipping (eversion) or bulging into atria when ventricles contract

Question 24

1) The semilunar (SL) valves regulate the openings between what?
2) The pulmonary SL valve controls the opening from what heart chamber to what blood vessel?
3) The aortic SL valve controls the opening from what heart chamber to what blood vessel?

Answer 24

1) The semilunar valves regulate the exits of the ventricles.
2) The pulmonary SL valve controls the opening between the right ventricle and the pulmonary trunk
3) The aortic SL valve controls the opening between the left ventricle and the aorta.

Question 25

1) The semilunar valves make no muscular effort but are simply pushed open and closed by what?
2) How many cusps do SL valves have? Do they have tendinous cords?

Answer 25

1) The valves make no muscular effort but are pushed open and closed by ventricular pressure
2) The SL valves have 3 cusps and do not have chordae tendineae

Question 26

Regarding blood flow, what is happening when the ventricles contract? Include where the blood is going, what valves are open or closed and ventricular pressure?

Answer 26

When the ventricles contract, blood is being pushed out of the heart/ ventricles. When the left ventricle contracts, the bicuspid valve is closed, and due to high ventricular pressure blood goes out the aortic semilunar valve and into the aorta, then to the rest of the body. When the right ventricle contracts, the tricuspid valve is closed, and due to high ventricular pressure blood goes out the pulmonary semilunar valve, into the pulmonary trunk, and into the lungs.

Question 27

Regarding blood flow, what is happening when the ventricles relax? Include where the blood is going, what valves are open or closed and ventricular pressure

Answer 27

When the ventricles relax, the SL valves are closed, the bicuspid and tricuspid valves are open, and the ventricles are filling up with blood from the atriums due to gravity.

Question 28

Be able to trace blood flow from the right atrium all the way to the systemic circulation, i.e., through the aorta. Be sure to include heart chambers, heart valves, lungs as part of the tracing.

Answer 28

1) Superior and inferior venae cavae
2) Coronary sinus
3) Right atrium
4) Tricuspid valve (right AV valve)
5) Right ventricle
6) Pulmonary semilunar valve
7) Pulmonary trunk
8) Left and right pulmonary arteries
9) Alveolar capillaries of the left and right lungs; here the blood picks up O2 and releases CO2
10) Four pulmonary veins (2 left & 2 right)
11) Left atrium
12) Bicuspid valve
13) Left ventricle
14) Aortic semilunar valve
15) Ascending aorta
16) Body’s tissues

Question 29

How much of the blood supply is pumped to the heart muscle? When does this occur, when the heart is contracting or when the heart is relaxed?

Answer 29

5% of blood pumped by the heart is pumped into the cardiac muscle
This occurs when the heart is relaxed

Question 30

Name the two major arteries that supply the heart. What blood vessel did the arteries branch off of?

Answer 30

The right & left coronary arteries supply the heart, and they branch from the ascending aorta

Question 31

1) What is angina pectoris?
2) What is a cause?
3) Why does a person feel pain?

Answer 31

1) Defined as chest pain from partial obstruction of coronary blood flow (ischemia)
2) The cause is that an obstruction partially blocks blood flow
3) The myocardium shifts to anaerobic respiration/fermentation, producing lactate and thus stimulating pain

Question 32

1) What is a myocardial infraction (MI)?
2) What is a cause?
3) Why does arterial anastomoses offer some protection?

Answer 32

1) Defined as a heart attack
2) The cause is the sudden death of a patch of myocardium resulting from long-term obstruction of coronary circulation; the obstruction is often a blood clot or fatty deposit (atheroma)
3) Some protection from MI is provided by arterial anastomoses because they provide alternative routes of blood flow (collateral circulation) within the myocardium

Question 33

What are cardiocytes (cardiomyocytes); are they striated? If cardiac muscle is damaged, repair is mostly fibrosis which means what?

Answer 33

Cardiomyocytes are cardiac muscle cells; they’re striated, short, thick, branched cells
Repair of damage of cardiac muscle is almost entirely by fibrosis, which means scarring

Question 34

What are the functions of the interdigitating folds and gap junctions?

Answer 34

1) Interdigitating folds: The plasma membrane at the end of the cardiomyocyte is folded somewhat like the bottom of an egg carton. The folds of adjoining cells interlock with each other and increase the surface area of intercellular contact
2) Gap junctions: They form channels that allow ions to flow from the cytoplasm of one cardiomyocyte directly into the next. They enable each cardiomyocyte to electrically stimulate its neighbors. Thus, the entire myocardium of the two atria behaves almost like a single cell, as does the entire myocardium of the two ventricles. This unified action is essential for the effective pumping of a heart chamber.

Question 35

What are the functions of the desmosomes and fascia adherens?

Answer 35

Desmosomes: Helps tightly join cardiomyocytes; a type of mechanical junction
Fascia adherens: Helps tightly join cardiomyocytes; a type of mechanical junction

Question 36

1) In terms of metabolism, cardiac muscle depends almost exclusively on what type of respiration to make ATP?
2) Because of that, what organelle do you expect to see in abundance?

Answer 36

Cardiac muscle depends almost exclusively on aerobic respiration to make ATP
This means they have a lot of mitochondria

Question 37

1) Cardiac muscle is adaptable to fuel source, but what is it vulnerable to?
2) Why is it important to be fatigue resistant?

Answer 37

1) Cardiac muscle may be adaptable to fuel source, but it’s vulnerable to oxygen deficiency
2) It’s important for the heart to be fatigue resistant since it literally cannot ever stop pumping until you die.

Question 38

Describe autorhythmic cells; do they contract

Answer 38

Autorhythmic cells: They’re composed of an internal pacemaker and nerve-like conduction pathways through myocardium that initiate and distribute action potentials through the heart. These action potentials lead to depolarization and contraction of the rest of myocardium. These cells do not contract.

Question 39

Which parts of the conduction system spontaneously generate an action potential?

Answer 39

The SA node typically generates the action potential, but all components of the conduction system are capable of generation an AP (ectopic focus)

Question 40

The cardiac conduction system generates rhythmic electrical signals in a particular order. What is that order?

Answer 40

SA node, AV node, AV bundle/ bundle of HIS, AV bundle branches, Purkinje fibers.

Question 41

1) Regarding the nerve supply to the heart, which increases heart rate and contraction strength; sympathetic or parasympathetic?
2) Which slows heart rate?

Answer 41

1) Sympathetic nerves increase heart rate and contraction strength
2) Parasympathetic nerves slow heart rate

Question 42

Define systole.
Define diastole.
When you use systole or diastole, are you referring to the action of the ventricles or the atria?

Answer 42

Systole: contraction
Diastole: relaxation
Usually refer to the action of the ventricles

Question 43

What is sinus rhythm? What part of the cardiac conduction triggered the sinus rhythm?

Answer 43

Sinus rhythm: normal heartbeat triggered by the SA node

Question 44

What is the normal range in resting adults in beats per minute (bpm)? How fast does the SA node actually fire? What nerve slows it down to the normal range? Is that sympathetic or parasympathetic?

Answer 44

SA node’s normal firing rate is actually about 100 bpm, but the vagus nerve slows it to ~75 bpm (vagal tone); parasympathetic

Question 45

1) Any region of spontaneous firing other than the SA node is called what?
2) What is nodal rhythm?

Answer 45

1) Any region of spontaneous firing other than the SA node is called ectopic focus.
2) Nodal rhythm: If the SA node is damaged, the AV node will set heart rate to 40 to 50 bpm.

Question 46

If the heart rate is 40 to 50 bpm, what part of the conduction system is triggering the nodal rhythm?

Answer 46

AV node

Question 47

If you produce an even slower heart rate of 20 to 40 bpm, does a heart rate that slow provide enough flow to the brain for it to survive? When do you need to use an artificial pacemaker?

Answer 47

If it’s any other type of ectopic focus other than nodal rhythm (i.e lower than 40 bpm), then the heart rate is too slow to sustain life; you need to use a pacemaker if the ectopic focus is anything other than the AV node.

Question 48

1) Do the cells of the SA node have a stable resting potential meaning the line is flat or does it drift upwards?
2) What electrolyte causes the gradual depolarization? 3) Why is this called the pacemaker potential?

Answer 48

1) The SA node does NOT have a stable resting membrane potential; the line drifts upwards
2) The influx of Sodium (Na) ions causes gradual depolarization of the SA node
3) This is called pacemaker potential because it shows a chance for depolarization

Question 49

1) When the SA node reaches threshold, what electrolyte channel opens to cause faster depolarization?
2) What channel opens to cause repolarization?

Answer 49

1) When it reaches threshold, the voltage-gated calcium ion and sodium ion channels open, which causes faster depolarization
2) The K+ channels opening and potassium leaving the cell cause repolarization

Question 50

Each depolarization of the SA node sets off one heartbeat. At rest, the SA node typically fires every ___ second or so, creating a heart rate of ____ bpm

Answer 50

0.8; 75 bpm

Question 51

1) The SA node stimulates the two atria to contract, even though the SA node is in the right atria, what cell junction allows the near simultaneous depolarization? 2) Why is there a delay as the signal goes through the AV node?

Answer 51

1) The gap junctions allow for near simultaneous depolarization
2) There’s a delay in signal through the AV node to give the atria time to finish contracting, and the ventricles time to finish filling

Question 52

1) The signal speeds up through the last three structures of the heart’s conduction system, which are what?
2) Where does ventricular systole start, from the apex or from the base?

Answer 52

1) Bundle of HIS/ AV bundle, Bundle branches, and Purkinje fibers
2) Ventricular systole starts at the apex of the heart and twists it

Question 53

1) The cells of the heart that actually contract are called what? What is their resting membrane potential?
2) What gates open to cause the cells to depolarize?

Answer 53

1) The cells that actually contract are called cardiomyocytes and they have a stable resting potential of -90mV
2) The Na+ voltage-regulated gates open, causing the cell to depolarize

Question 54

1) What is the purpose of the plateau phase? What electrolyte is responsible for the plateau phase in these contracting cells?
2) What channel closes and what channel opens for repolarization to occur?

Answer 54

1) The plateau phase is to sustain contraction for the expulsion of blood from the heart, this is because the Ca2+ channels open, allowing Ca2+ to flow in from the ECF
2) For repolarization to occur, Ca2+ channels close, and K+ channels open, causing K+ to rapidly diffuse out of the cell.

Question 55

In what kind of cells does the “plateau phase” occur?

Answer 55

In cardiomyocytes

Question 56

The absolute refractory period in cardiomyocytes is 250 ms, compared to ~2 ms in skeletal muscle, why the difference in absolute refractory period?

Answer 56

To prevent wave summation and tetanus which would stop the pumping action of the heart

Question 57

Can you identify key differences between skeletal muscle and the heart conduction system regarding the following: resting membrane potential, whether a neurotransmitter is required, slow depolarization to threshold, and where does the action potential lead to?

Answer 57

1) Skeletal muscle: Stable resting membrane potential of -90mv; requires motor neuron to release Ach, depolarization of motor end plate, action potential leads to sarcolemma across muscle cell
2) Heart conduction system: SA node membrane potential very unstable, starts at -60mv; have slow depolarization before threshold and fast after, action potential leads to rest of conduction system and and muscle cell connected by gap junctions.

Question 58

1) Can you identify commonalities between skeletal muscle and myocardium regarding depolarization, repolarization?
2) Can you identify differences between skeletal muscle and myocardium regarding plateau, length of action potential, and length of contraction?

Answer 58

1) Similarities: Na+ rushes in during both their depolarization phases, K+ rushes out during both repolarization phases, both need Na+ and K+
2) Differences: In myocardium there’s a plateau caused by Ca2+ flowing in; myocardium has much longer action potential (200-250ms vs 1-2ms); myocardium has a longer contraction (200ms vs 15-100ms).

Question 59

1) An ECG is a composite recording of all action potentials produced by what cells?
2) A typical ECG shows what?

Answer 59

1) A composite of all action potentials produced by nodal and myocardial cells
2) Typically shows a P wave, QRS complex, ST segment, and T wave

Question 60

Can you describe what is going on during each of the following: P wave, PQ segment, QRS complex, ST segment and T wave?

Answer 60

P wave: atrial depolarization
PQ segment: atrial systole
QRS complex: atrial repolarization (hidden) and ventricular depolarization
ST segment: ventricular systole
T wave: ventricular repolarization and diastole

Question 61

1) What could ECG/ECK deviations indicate?
2) What is ventricular fibrillation? Why is this serious?

Answer 61

1) ECG deviations could indicate: Myocardial infarction (MI), abnormalities in conduction pathways, heart enlargement, or electrolyte and hormone imbalances
2) Ventricular fibrillation: Serious arrhythmia caused by electrical signals traveling randomly. This means that the heart cannot pump blood; no coronary perfusion. It’s a hallmark of heart attack (MI) and kills quickly if not stopped

Question 62

What is a defibrillation and what is it designed to do to the heart?

Answer 62

Defibrillation is a strong electrical shock designed to depolarize the entire heart at once

Question 63

1) A cardiac cycle consists what?
2) What does a sphygmomanometer measure?

Answer 63

1) Cardiac cycle: one complete contraction and relaxation of all four chambers of the heart
2) A sphygmomanometer measures blood pressure

Question 64

1) What are the two main variables that govern fluid movement?
2) Do you have to have a pressure gradient? In what direction does fluid flow, from low to high or from high to low?

Answer 64

1) The two main variables the govern fluid movement are that pressure causes flow and resistance opposes it.
2) Fluid will only flow if there is a pressure gradient (pressure difference; flows high to low)

Question 65

If you increase the volume, what happens to pressure? If you decrease the volume, what happens to pressure?

Answer 65

Increasing volume decreases pressure; decreasing volume increases pressure.

Question 66

What happens to the pressure in the ventricles if the ventricles relax and expand? Which of the heart valves are open? Which of the heart valves are closed? What chambers are blood flowing into?

Answer 66

When the ventricles are relaxed, the AV valves are open and the semilunar valves are closed, and blood is flowing into the ventricles.

Question 67

What happens to the pressure in the ventricles if the ventricles contract and internal pressure rises? Which of the heart valves are open? Which of the heart valves are closed? What vessels are the blood flowing into?

Answer 67

Pressure rises in the ventricles if the ventricles contract and get smaller. When the ventricles are contracted, the AV valves are closed and the semilunar valves are opened, and blood is flowing out if the ventricles into the blood vessels (aorta from left side and pulmonary trunk from right side)

Question 68

1) When the ventricles are in (mid) diastole, are the AV valves open or closed?
2) When the ventricles are in systole, are the AV valves open or closed?
3) When the ventricles are in (mid) systole, are the semilunar valves open or closed?
4) When the ventricles are in diastole, are the semilunar valves open or closed?

Answer 68

1) When the ventricles are in mid diastole, the ventricles are filling and the AV valves are opened
2) When the ventricles are in early systole, the AV valves are closed
3) When the ventricles are in mid systole, the semilunar valves are open.
4) When the ventricles are in early diastole, the semilunar valves are closed.

Question 69

What is a valvular stenosis disorder? What is a likely cause?

Answer 69

Valvular stenosis: When the valvular cusps are stiffened and opening is constricted by scar tissue (such as from rheumatic fever); unable to prevent the backflow of blood (valvular insufficiency disorder)

Question 70

1) What is a mitral valve prolapse?
2) Define heart murmur.

Answer 70

1) Mitral valve prolapse: an insufficiency in which one or both mitral valve cusps bulge into the atrium during ventricular contraction; unable to prevent the backflow of blood (valvular insufficiency disorder)
2) Heart murmur: abnormal heart sound

Question 71

1) What is auscultation?
2) What are these two main sounds and what valves are closing to produce the sound?

Answer 71

1) Auscultation: Listening to sounds made by the body
2)
-First heart sound (𝐒𝟏), louder and longer “lubb,” occurs with closure of AV valves
-Second heart sound (𝑺𝟐), softer and sharper “dupp,” occurs with closure of semilunar valves

Question 72

The first heart sound occurs with the closure of the __________ valves, whereas the second heart sound occurs with the closure of the _________ valves

Answer 72

AV; semilunar

Question 73

The cardiac cycle can be described as having four phases, all of which are completed in less than 1 second. As the ventricles relax and expand during diastole, what valves are open and what valves are closed?

Answer 73

During early diastole, as the valves relax and expand, there are no valves open; this is called isovolumetric filling. Then, the AV valves open.

Question 74

During Isovolumetric contraction, what valves are open and what valves are closed? What is blood doing in this phase?

Answer 74

No valves are open, and blood is in the ventricles.

Question 75

During Isovolumetric relaxation, what valves are open and what valves are closed? What is blood doing in this phase? What phase occurs next?

Answer 75

No valves are open and blood is in the atria. The next phase is ventricular relaxation.

Question 76

1) What is the end-systolic volume? Are the chambers completely empty?
2) What is stroke volume?
3) Do both ventricles eject the same amount of blood?

Answer 76

1) End-systolic volume: The blood left behind in the ventricles after ventricular ejection; typically 60ml. The chambers are not completely empty
2) Stroke volume: The amount of blood ejected from the ventricles per contraction, typically 70ml
3) Both ventricles need to eject the same amount of blood.

Question 77

What is congestive heart failure?
What are possible causes?

Answer 77

1) Congestive heart failure (CHF) results from the failure of either ventricle to eject blood effectively
2) Usually due to a heart weakened by myocardial infarction, chronic hypertension, valvular insufficiency, or congenital defects in heart structure

Question 78

1) If the right ventricle pumped more blood, the blood would accumulate in the lungs causing what? Which ventricle failed?
2) If the left ventricle pumped out more blood, blood would accumulate in the systemic circuit and cause what? Which ventricle failed? If uncorrected this leads to what?

Answer 78

1) If the right ventricle pumped more blood, the blood would accumulate in the lungs causing a pulmonary edema; this would mean the left ventricle failed.
2) If the left ventricle pumped out more blood, blood would accumulate in the systemic circuit and cause a systemic edema; this would mean the right ventricle failed. Eventually leads to total heart failure if left uncorrected.

Question 79

Define stroke volume and cardiac output.
What is cardiac reserve?

Answer 79

1) Stroke volume: The amount of blood ejected from a ventricle per contraction, typically 70ml
Cardiac output (CO): The amount of blood ejected by each ventricle in 1 minute (heart rate x stoke volume)
2) Cardiac reserve: the difference between a person’s maximum and resting CO; increases with fitness, decreases with disease

Question 80

1) How does the resting heart rate change over the course of a person’s life?
2) What is Tachycardia and what causes it?
3) What is Bradycardia? When or who is it common in?

Answer 80

1) Babies have high resting heart rates, then it decreases throughout childhood into young adulthood, then it steadily rises until the end of life.
2) Tachycardia: Fast heart rate (>100bpm); anxiety, caffeine, nicotine
3) Bradycardia: Slow heart rate (<60 bpm); extreme athleticism, ectopic focus

Question 81

1) Factors that raise the heart rate are called?
2) Factors that lower it are called?
3) Increasing heart rate will increase cardiac output up to a point, then cardiac out declines, why?

Answer 81

1) Positive chronotropic agents: factors that raise the heart rate
2) Negative chronotropic agents: factors that lower the heart rate
3) At a certain point in increasing heart rate, cardiac output will decline because if heart is going too fast, there is no time between contractions to fill the ventricles, so the ventricles are less efficient and cardiac output goes down.

Question 82

The sympathetic nervous system is a ______ chronotropic agent, whereas the parasympathetic nervous system is a _______ chronotropic agent

Answer 82

positive; negative

Question 83

1) In what organ is the cardiovascular center?
2) What 2 areas can influence signal with their input?

Answer 83

1) The cardiovascular center is in the Medulla of the brain
2) The cerebral cortex and limbic system can influence the cardiovascular center’s signals with their output

Question 84

1) If proprioceptors are activated, what happens to HR? Does it increase or decrease?
2) If baroreceptors are activated, what happens to HR? Does it increase or decrease?
3) If chemoreceptors are activated, what happens to HR? Does it increase or decrease?

Answer 84

1) If proprioceptors are activated, heart rate will increase
2) If baroreceptors are activated, they can either increase or decrease heart rate depending on blood pressure
3) If chemoreceptors are activated, heart rate increases to dispose of CO2 and wastes

Question 85

Which are some positive chronotropic agents?
Which are some negative chronotropic agents?

Answer 85

1) Positive chronotropic agents: Nicotine, caffeine, thyroxine, epinephrine
2) Negative chronotropic agents: Potassium, beta blockers

Question 86

1) What three variables impact stroke volume?
2) Which of the variables, if increased, increases stroke volume?
3) Which of the variables, if increased, decreases stroke volume?

Answer 86

1) Three variables affect stroke volume: Preload, contractility, and afterload
2) Stroke volume increases with increased preload or contractility
3) Stroke volume decreases with increased afterload

Question 87

What is preload? What activity can cause this to increase?

Answer 87

1) Preload: the amount of tension in ventricular myocardium immediately before it begins to contract
-Increased preload causes increased force of contraction
2) Exercise increases venous return and stretches myocardium

Question 88

Frank-Starling law of the heart states what?

Answer 88

That stroke volume is proportional to the end diastolic volume
-Ventricles eject almost as much blood as they receive
-The more they are stretched, the harder they contract

Question 89

1) Contractility refers to what?
2) Factors that increase contractility are called what? Examples?
3) Factors that decrease contractility are called what? Examples?

Answer 89

1) Contractility refers to how hard the myocardium contracts for a given preload
2) Positive inotropic agents increase contractility: Hypercalcemia, catecholamines, glucagon, and digitalis
3) Negative inotropic agents decrease contractility: Hypocalcemia, hyperkalemia, acidosis, and drugs such as calcium channel blockers

Question 90

1) What is afterload?
2) What increases afterload?
3) Why is an increased afterload damaging to the heart?

Answer 90

1) Afterload: The sum of all forces opposing ejection of blood from ventricle; mostly is the blood pressure in aorta and pulmonary trunk
-Opposes the opening of semilunar valves
-Limits stroke volume
2) Hypertension and anything that impedes arterial circulation increases afterload.
3) Increased afterload is damaging due to the fact that it can cause many complications such as ventricular failure.

Question 91

Define flow. Define perfusion. Can a large organ have a greater flow but less perfusion than a small organ? Explain.

Answer 91

1) Flow is amount of blood flowing through an organ, tissue, or blood vessel in a given time (mL/min/g)
2) Perfusion is the flow per given volume or mass of tissue in a given time (mL,min,g)
3) Yes, because while the flow may be normal, parts of a tissue’s perfusion could be affected by abnormalities such as clots.

Question 92

The blood vessel walls of arteries and veins are composed of how many layers or tunics? The tunica interna (tunica intima) is found where? What is it exposed to What type of tissue does it consist of? The endothelium acts as a what? It secretes chemicals that stimulate what?

Answer 92

1) 3 layers of tunics
2) Tunic interna (intima) is the inner layer, and it is endothelium. It is a selectively permeable barrier and secretes chemicals that stimulate dilation or constriction. It normally repels blood cells and platelets.

Question 93

What layer is the tunica media? What tissue does it consist of? What nervous system regulates it, sympathetic or parasympathetic? Why is this layer important in terms of blood pressure? What does it do? What happens to the lumen diameter during vasoconstriction or vasodilation?

Answer 93

1) Tunica Media: smooth muscle, collagen, and elastic tissue. Regulated in part by sympathetic nervous system; controls vasoconstriction and vasodilation
2) During vasoconstriction the lumen diameter decreases, during dilation the diameter increases. The larger the diameter, the lower the blood pressure

Question 94

What is the outmost layer called besides tunica externa? Why does it have collagen fibers? What does it anchor and who does it provide a passage for? Small vessels called the vasa vasorum supply blood to?

Answer 94

1) Tunica externa or adventitia: Made of collagen fibers, which protect and reinforce blood vessels.
2) It anchors the blood vessel and provides passage for small nerves and lymphatic vessels
3) The small vessels called Vasa vasorum supply blood to outer part of larger vessels

Question 95

1) Arteries are built to withstand the surges of?
2) Conducting (elastic or large) arteries are what in terms of size? Can you describe them (for example their tunica media) and how they help with pressure?
3) Can you name some examples?

Answer 95

1) They’re built to withstand surges of blood
2) Conducting arteries: They’re the biggest arteries Have layers of elastic tissue. They expand during systole, taking pressure, and recoil during diastole to help maintain pressure inside of arteries to keep blood flowing.
3) Examples: aorta, common carotid, subclavian, pulmonary trunk, and common iliac arteries.

Question 96

Distributing (muscular or medium) arteries are smaller branches that distribute blood to specific organs. What are some examples?

Answer 96

Distributing or medium arteries: Distribute blood to specific organs; smooth muscle layers make up 3/4 of their wall’s thickness.
1) Examples: Brachial, Femoral, renal, and splenic arteries.

Question 97

The smallest of the resistance (small) arteries are called what?
What are metarterioles?
Why do metarterioles have a precapillary sphincter?

Answer 97

1) Arterioles are the smallest arteries. They have a thicker tunica media in proportion to their lumen, and very little tunica externa.
2) Metarterioles are located in some places, and are short vessels that link arterioles to capillaries.
3) They have a precapillary sphincter that controls blood going into the bed

Question 98

What is an aneurysm? Where are common sites?

Answer 98

1) A weak point in artery or heart wall. Forms a thin-walled bulging sac that pulsates with each heartbeat and may rupture at any time.
2) Most common sites: abdominal aorta, renal arteries, and arterial circle at base of brain.

Question 99

1) Sensory structures transmit signals to the brainstem to regulate what 3 things?
2) What do the carotid sinuses measure and what is the name of their receptors?
3) What do the carotid bodies measure and what is the name of their receptors?
4) What do the aortic bodies measure and what is the name of the receptors?

Answer 99

1) Sensory structures help to regulate heart rate, blood vessel diameter, and respiration.
2) The carotid sinuses have baroreceptors that measure blood pressure
3) The carotid bodies have chemoreceptors that measure chemical changes in blood composition
4) Aortic bodies have chemoreceptors and they measure chemical changes in blood composition

Question 100

Why are capillaries sometimes called exchange vessels? What layers or tunica are found in blood capillaries?

Answer 100

1) Capillaries are sometimes called exchange vessels because of the exchange process that happens here between the capillaries and tissues; nutrients and oxygen enter the tissues and wastes and carbon dioxide enter the capillaries.
2) They’re composed of endothelium and basal lamina

Question 101

Describe the 3 types of capillaries and where they’re found

Answer 101

1) Continuous occurs in most tissues, and have tight junctions to hold endothelial cells together; the least permeable.
2) Fenestrated has lots of tiny holes and occurs in places where filtration occurs, such as the kidneys. 3) Sinusoids have the largest holes and are the most permeable; their holes are big enough to allow RBCs and proteins to escape, so they’re found in the bone marrow and liver.

Question 102

Capillaries are organized into networks called what? What vessel supplies the capillary network?

Answer 102

Capillaries are organized into capillary beds, which are networks of 10-100 capillaries supplied by a single arteriole or metarteriole.

Question 103

What structure controls the flow into the capillary network? About three-quarters of the body’s capillaries are shut down at any given time, why is this?

Answer 103

1) Precapillary sphincters control flow as well as the constriction of arterioles upstream.
2) About 3/4 of capillaries are shut down at any given time because we don’t have enough blood to fill them all up at the same time.

Question 104

At their distal end, capillaries transition into what vessel?

Answer 104

At their distal end, capillaries transition into veins.

Question 105

Veins are considered the capacitance vessels of the cardiovascular system. Why is this?

Answer 105

Veins are considered the capacitance vessels because they have greater capacity for blood than arteries because their lumen are bigger.

Question 106

1) Are the walls of veins thin or thick?
2) What structure is found in veins that is not in arteries? In what layer or tunic is this structure in, and what purpose does it serve?

Answer 106

1) They have thinner walls so they can collapse when empty and expand easily.
2) They have valves in their tunica intima, which arteries do not, to ensure a lack of backflow (due to their low pressure).

Question 107

Postcapillary venules are the smallest of the veins and they received blood from what vessels?

Answer 107

Post capillary venules: receive blood from capillaries.

Question 108

1) What are venous sinuses? Are they able to vasoconstrict?
2) What venous sinus did you learn with the heart?

Answer 108

1) Venous sinuses: veins with especially thin walls, large lumens, and no smooth muscle (so they cannot vasoconstrict).
2) Examples include the dural venous sinus (brain) and coronary sinus of the heart (wall of heart.)

Question 109

Large veins are denoted by diameter, what are some of the large veins?

Answer 109

Larger than 10mm in diameter. Ex: venae cavae, pulmonary veins, internal jugular veins, and renal veins.

Question 110

In a resting adult most of blood is in ________

Answer 110

veins

Question 111

What are varicose veins? What are causes?

Answer 111

1) Varicose veins are when blood pools in the veins of lower legs due to backflow.
2) Typically occurs in people who stand for long periods of time; this stretches veins and pulls them down, so one way valves fail and blood back flows, further distends the vessels, and their walls grow weak.
Also occurs due to hereditary weakness, obesity, and pregnancy

Question 112

Hemorrhoids are varicose veins located where?

Answer 112

In the anal canal

Question 113

The simplest and most common route for blood is what?

Answer 113

Heart> arteries > arterioles > capillaries.> venules> veins > Heart

Question 114

In a portal system, blood is flowing through how many capillary networks? Where do portal systems occur?

Answer 114

1) In a portal system, blood flows through two consecutive capillary networks before returning to heart
2) Examples include: Between hypothalamus and anterior pituitary; in kidneys; between intestines to liver

Question 115

1) What is an anastomosis?
2) In an arteriovenous anastomosis (shunt), blood flows from an ______________ directly into a _________________, bypassing capillaries.

Answer 115

1) An anastomosis is a convergence point between two blood vessels other than capillaries.
2) In an arteriovenous anastomosis (shunt), blood flows from an artery directly into a vein, bypassing capillaries.

Question 116

The most common anastomoses are what? What advantage does this have when a blockage occurs?

Answer 116

Venous anastomosis are most common; vein blockage is less serious than arterial anastomosis.

Question 117

What is an arterial anastomoses? Why is this important in the coronary circulation?

Answer 117

An arterial anastomosis provides collateral or alternative routes of blood supply to a tissue; this is important in coronary circulation because it provides alternate routes in case of a blockage.

Question 118

1) Define flow.
2) Define perfusion.
3) Can a large organ have a greater flow but less perfusion than a small organ?

Answer 118

1) Flow is amount of blood flowing through an organ, tissue, or blood vessel in a given time (mL/min/g)
2) Perfusion is the flow per given volume or mass of tissue in a given time (mL,min,g)
3) Yes, because while the flow may be normal, parts of a tissue’s perfusion could be affected by abnormalities such as clots.

Question 119

What is the typical value for cardiac output in L/min?

Answer 119

5.25 L/min at rest

Question 120

What two properties is blood flow based on?

Answer 120

Pressure and resistance.

Question 121

1) The greater the pressure difference between two points, what does that do to flow?
2) The greater the resistance, what does that do to flow?

Answer 121

1) The greater the pressure difference b/t two points then the greater the flow.
2) The greater the resistance the less the flow.

Question 122

1) Define blood pressure (BP).
2) What are the names of the two pressures that are recorded?
3) What is the normal value for a young adult?

Answer 122

1) Blood pressure is the force blood exerts against a vessel wall.
2) The 2 pressures are systolic and diastolic; systolic is when heart contracts (highest pressure) and diastolic is when heart relaxes (lowest pressure)
3) The normal values for a young adult is 120/75

Question 123

How is bleeding different between an injured vein and an injured artery?

Answer 123

The further from the heart, the less pressure, so bleeding from an artery blood is pulsatile (i.e. it is going to shoot out quickly and sporadically), but bleeding from a vein flows at slower, steady speed .

Question 124

What are reasons BP rises with age in regards to arteriosclerosis and atherosclerosis?

Answer 124

Bp rises with age because of arteriosclerosis (the stiffening of arteries bc of deterioration of elastic tissues of artery walls) and atherosclerosis (build up of lipid deposits that becomes plaques).

Question 125

Define hypertension. What is the clinical description of hypertension?

Answer 125

Hypertension: High blood pressure most common cardiovascular disease. chronic resting bp over 140/90 it can weaken arteries, cause aneurysms, promote atherosclerosis.

Question 126

Define hypotension. What are reasons an individual has hypotension?

Answer 126

Hypotension is low blood pressure; it’s typically caused by blood loss, dehydration, or anemia. Known as a “silent killer”

Question 127

What three factors determine BP? What two factors make up cardiac output?

Answer 127

-Blood pressure is determined by cardiac output, blood volume, and resistance to flow
-Cardiac output: Cardiac output = stroke volume x hr.
-If cardiac output increases bp increases.

Question 128

What regulates blood volume? If blood volume goes up, what happens to BP?

Answer 128

Blood volume: regulated mainly by kidneys; if blood volume goes up, bp goes up.

Question 129

1) Define resistance.
2) If resistance goes up, what happens to BP?
3) What three variables control resistance?

Answer 129

1) Resistance to flow: The amount of friction blood encounters as it passes through vessels.
2) If resistance goes up bp goes up.
3) Three variables control resistance: Blood viscosity, vessel length, and vessel radius.

Question 130

Blood viscosity is determined by several factors, such as? Increased viscosity will do what to resistance?

Answer 130

1) Blood viscosity is primarily determined by RBC count and albumin concentration, both of which will elevate viscosity the most.
2) Increased viscosity will increase resistance

Question 131

1) The farther a liquid travels through a tube, such as a vessel, the more cumulative friction it encounters, so what will this do to resistance?
2) Which is the most powerful influence over flow?

Answer 131

1) Vessel length: The farther liquid travels through a tube, the more cumulative friction it encounters, which leads to increased resistance.
2) The most powerful influence over blood flow and pressure is vessel radius.

Question 132

1) What are vasoreflexes?
2) Vasoconstriction occurs when smooth muscle does what?
3) Vasodilation is the result of the muscle doing what?

Answer 132

1) Vasoreflexes: vasoconstriction and vasodilation
2) Vasoconstriction: Smooth muscle constricts, leads to smaller diameter
3) Vasodilation: The smooth muscle relaxing, leads to larger diameter

Question 133

What layer is the smooth muscle in?
Is resistance greater when the diameter is larger or smaller and why?

Answer 133

1) The smooth muscle is in the tunica media
2) The smaller the diameter, the more resistance, because there is less room for blood to flow freely

Question 134

If resistance increases what happens to blood pressure? If resistance increases, what happens to blood flow?

Answer 134

If resistance increases, bp increases. If resistance increases, blood flow decreases.

Question 135

From the aorta to capillaries, give three reasons why the blood velocity (speed) decreases?

Answer 135

1) There’s a greater distance to get to the capillaries, which leads to more friction, which reduces speed.
2) The smaller radii of arterioles and capillaries offers more resistance, which reduces speed
3) Further from heart, the number of blood vessels and their total cross sectional area becomes greater and greater, offering more resistance, which reduces speed.

Question 136

From the capillaries to vena cava, give reasons why the blood velocity (speed) increases?

Answer 136

Since veins are larger than capillaries, they create less resistance.
However, blood in veins never regains velocity it had in large arteries.
This is due to low pressure and the fact that veins are more compliant (stretch more) than arteries

Question 137

What is vasomotion?

Answer 137

Vasomotion is vasoconstriction and vasodilation.

Question 138

What are the 3 types of control over vasomotor activity?

Answer 138

Local control, neural control, and hormonal control

Question 139

1) Define autoregulation in regards to local control.
2) What would conditions would stimulate vasodilation?
3) What would have to happen in order to get those same vessels to constrict?

Answer 139

1) Local control/ Autoregulation (Metabolic theory):
The ability of tissues to regulate their own blood supply
2) The accumulation of wastes stimulates vasodilation (increases perfusion)
–Chemicals secreted by platelets, endothelial cells, etc. Histamine, Bradykinin, and Nitric oxide stimulate vasodilation
3) When wastes are removed, vessels constrict

Question 140

Explain how neural control impacts vasomotor activity

Answer 140

Neural control: Vasomotor center of medulla exerts sympathetic control over blood vessels throughout the body
Vasomotor center is the integrating center for 3 reflexes: Baroreflexes, chemoreflexes, and medullary ischemic reflex

Question 141

Explain how hormonal control impacts vasomotor activity

Answer 141

Increases and decreases BP

Question 142

Explain reactive hyperemia in regards to local control. Can you give an example?

Answer 142

Reactive hyperemia: If blood supply cut off then restored, flow increases above normal
Ex: taking blood pressure

Question 143

Explain angiogenesis in regards to local control. Can you give an example?

Answer 143

Angiogenesis: growth of new blood vessels
Occurs in regrowth of uterine lining, around coronary artery obstructions, in exercised muscle, and malignant tumors

Question 144

1) In regards to neural control, what organ is exerting control over blood vessels throughout the body?
2) Why would it dilate vessels in the cardiac system?

Answer 144

1) Vasomotor center of medulla exerts sympathetic control over blood vessels throughout the body.
2) It stimulates most vessels to constrict, but dilates the vessels in cardiac muscle; this is because you do not want to cut off blood supply to heart muscle.

Question 145

1) Describe baroreflexes. Are they short-term or long-term regulators of blood pressure?
2) Can you briefly describe how they regulate blood pressure?

Answer 145

1) Baroreflex: Short term regulation; an automatic negative feedback response to changes in blood pressure detected by carotid sinuses.
2) The regulation takes place as follows:
-Increase in bp is detected and the glossopharyngeal nerve sends signals to brainstem this results in: 1) The inhibition of sympathetic cardiac and vasomotor neurons, and 2) The excitation of vagal fibers that slow HR, and thus reduced bp.
-A decrease of bp has the opposite effect. This doesn’t work with chronic hypertension because the baroceptors get used to a constant high level and they ignore it.

Question 146

1) A chemoreflex is an _________ response to changes in blood chemistry.
2) Their primary role is to what?

Answer 146

1) autonomic
2) Adjust respiration according to changes in pH, O2, and CO2.

Question 147

1) The medullary ischemic reflex is an autonomic response to do what? What condition triggers this automatic response?
2) Input to these centers from other brain centers will do what to heart rate and BP?

Answer 147

1) The medullary ischemic reflex is an autonomic response to a drop in perfusion (ischemia) of the brain.
2) Cardiac and vasomotor centers send sympathetic signals to heart and blood vessels; this increases HR and contraction force, causes widespread vasoconstriction, raises bp, and restores normal perfusion to the brain.

Question 148

Can you name hormones that increase BP?
Can you name hormones that decrease BP?

Answer 148

1) BP increasing hormones: Angiotensin II, ADA, Epinephrine and norepinephrine
2) BP decreasing hormones: Atrial natriuretic peptide

Question 149

What are the two purposes of vasodilation and vasoconstriction?

Answer 149

1) The general method of raising or lowering BP requires vasodilation and vasoconstriction
2) The rerouting blood from one body region to another; this can be either centrally or locally controlled.

Question 150

Rerouting of blood flow and changes in the perfusion of individual organs can be achieved by central or local control. Can you give an example of when would this be important?

Answer 150

1)
1) This is important during exercise since the sympathetic system reduces blood flow to kidneys and digestive tract and increases blood flow to skeletal muscles.
2) This is important because it allows local metabolite accumulation in a tissue to affect local circulation without affecting circulation anywhere else in the body. If a specific artery constricts, the pressure downstream can drop, and pressure upstream can go up.

Question 151

If you are resting after a big meal, vasoconstriction shuts down blood flow to 90% of the capillaries where? Where is that blood directed?

Answer 151

Vasoconstriction shuts down blood flow to 90% of the capillaries in the legs
Blood is directed to digestive tract.

Question 152

During vigorous exercise, arteries dilate in the lungs, coronary circulation, and muscles; vasoconstriction occurs elsewhere, such as where?

Answer 152

During exercise vasoconstriction occurs in the digestive tract and urinary system

Question 153

Can you explain blood flow comparison looking at CO at rest versus CO at moderate exercise?

Answer 153

CO at rest is 5 L per minute evenly focusing on the digestive, muscular, renal and cerebral areas.
During exercise CO is 17.5 L per minute with the focus on the muscular region.

Question 154

What is capillary exchange? What substances get exchanged?

Answer 154

1) Capillary exchange is the bidirectional movement of fluid across capillary walls.
2) Substances that get exchanged include: water, oxygen, glucose, amino acids, lipids, minerals, antibodies, hormones, wastes, carbon dioxide, and ammonia.

Question 155

Can you list the three routes substances use to pass in capillary exchange?

Answer 155

1) Through the endothelial cells
2) Intercellular clefts b/t endothelial cells
3) Filtration pores (fenestration) of the fenestrated capillaries

Question 156

Can you describe diffusion, transcytosis, filtration and reabsorption? Include which is the most important.

Answer 156

1) Diffusion: The most important method; lipid soluble substances and gasses (O2 and CO2) diffuse through plasma membrane. Water soluble substances (glucose and electrolytes) diffuse through filtration pores and intercellular clefts; large particles (albumin) such as proteins are held back.
2) Transcytosis: Endothelial cells pick up material on one side of their membrane via endocytosis and discharge material on other side of membrane by exocytosis. Important for fatty acids, proteins, and some hormones like insulin.
3) Filtration and Reabsorption: Fluid filters out the arterial end of the capillary and osmotically reenters at the venous end. This determines relative fluid volumes of blood and interstitial fluid. Delivers materials to cells and removes metabolic wastes.

Question 157

In filtration and reabsorption, which end of the capillary filters out? Which end of the capillary has fluid osmotically reenter?

Answer 157

Fluid filters out the arterial end of the capillary and osmotically reenters at the venous end.

Question 158

1) What produces blood hydrostatic pressure?
2) What produces colloid osmotic pressure?

Answer 158

1) Blood hydrostatic pressure is produced by: cardiac output, blood volume and peripheral resistance.
2) Colloid osmotic pressure produced by the plasma proteins (albumin) and RBCs

Question 159

How much are capillaries able to reabsorb? What organ system is responsible for the remaining?

Answer 159

Capillaries are able to reabsorb 85%, the lymphatic system is responsible for the rest.

Question 160

Where are some locations that do filtration? What situations would increase filtration?

Answer 160

Filtration at the Glomeruli in the kidney: an area completely devoted to filtration. The alveolar capillary is devoted to reabsorption (keeps fluid out of air spaces).
Activity or trauma increases filtration

Question 161

Edema usually shows as swelling where? What are the three fundamental causes? Can you give some examples of each?

Answer 161

Edema usually occurs in face, fingers, abdomen, or ankles.
3 fundamental causes are:
1) Increased capillary filtration. Ex: kidney failure, histamine release, old age, poor venous return.
2) Reduced capillary absorption/reabsorption. Ex: hypoproteinemia, liver disease, dietary protein deficiency
3) Obstructed lymphatic drainage: Ex: surgical removal of lymph nodes

Question 162

Edema has multiple pathological effects such as?

Answer 162

Tissue necrosis, pulmonary edema: cerebral edema, severe edema, or circulatory shock

Question 163

What is venous return, and what are the five mechanisms that can achieve it?

Answer 163

-Venous return is the flow of blood back to the heart.
5 mechanisms:
1) Pressure gradient: Most important; pressure at venules (12-18mm Hg) drops to 5 mm Hg where the venae cavae enters the heart
2) Gravity: drains blood from the head and neck
3) Skeletal muscle pump: In the limbs; contracting muscle squeezes blood out of the compressed part of the vein; valves prevent backflow.
4) The thoracic (respiratory) pump: pressure changes during breathing, squeezes veins
5) Cardiac suction: Of expanding atrial space.

Question 164

How does level of physical activity affects venous return?

Answer 164

Exercise increases venous return in many ways: heart beats faster and harder increasing CO and BP; vessels of skeletal muscles, lung, and heart dilate and increase flow; increased respiratory, thoracic pump, and skeletal muscle pump movement.

Question 165

What is venous pooling? Why could venous pooling cause dizziness? What are non-surgical ways to compensate for venous pooling?

Answer 165

1) Venous pooling occurs with inactivity; venous pressure is not enough to force blood upward from prolonged standing, so CO may be low enough to cause dizziness.
2) This can be prevented by tensing leg muscles, which activates the skeletal muscle pump; jet pilots wear pressure suits to prevent this.

Question 166

What is cardiogenic shock and what is it caused by? What are the two basic types?

Answer 166

1) Cardiogenic shock: Any state in which cardiac output is insufficient to meet the body’s metabolic needs.
2) 2 basic types:
-Cardiogenic: inadequate pumping of the heart (MI)
-Low venous return (LVR): cardiac output is low because too little blood is returning to the heart.

Question 167

What are the causes/ types of low venous return shock?

Answer 167

1) Hypovolemic shock: most common; loss of blood volume due to trauma, burns, or dehydration
2) Obstructed venous return shock: tumor or aneurysm compresses a vein
3) Venous pooling (vascular) shock: long periods of standing, sitting, or widespread vasodilation.

Question 168

Can you describe the difference between neurogenic shock, septic shock and anaphylactic shock, including situations that trigger each type?

Answer 168

1) Neurogenic shock: Loss of vasomotor tone, vasodilation. Causes range from emotional shock to brain stem injury
2) Septic shock: Bacterial toxins trigger vasodilation and increased capillary permeability.
3) Anaphylactic shock: Severe immune response to an antigen causes histamine release, generalized vasodilation, and increased capillary permeability.

Question 169

What are the three main functions of the circulatory system? Be able to describe the functions in a single word and be able to further explain what that single word means relative to the circulatory system.

Answer 169

1) Transport: of O_2, CO_2, nutrients, wastes, hormones, and stem cells
2) Protection: Hemostasis and immune system
3) Regulation: Fluid balance, stabilizes pH of ECF, and temperature control

Question 170

What are the major components of the circulatory system?

Answer 170

Heart, blood vessels, and blood

Question 171

What components make up blood? What primary tissue did they originate from? Define the matrix and formed elements.

Answer 171

1) Plasma and the seven types of formed elements
2) Blood is a liquid connective tissue; all of the several blood cell types originate in the connective tissue of bone marrow
3) Plasma: extracellular matrix of blood
4) Formed elements: blood cells and cell fragments

Question 172

Which of the formed elements are not all cells? The ratio of formed elements to plasma is measured using what test?

Answer 172

1) Platelets are cell fragments
2) Hematocrit test measures the ratio of formed elements to plasma

Question 173

List physical properties of blood including viscosity, color, pH, location of blood components when centrifuged, and volume

Answer 173

Viscosity: Whole blood 4.5 to 5.5 times as viscous as water; plasma is 2.0 times as viscous as water
Color: Red
pH: 7.35-2.45
When centrifuged: RBCs on bottom, the a buffy coat of WBCs and platelets, then plasma on top (55% of volume)

Question 174

What is the composition of components in blood plasma including its average percent in a blood sample? Include some nutrients and some waste products.

Answer 174

Composition: 55% plasma, 45% RBCs, 1% WBCs and platelets
Nutrients: Glucose, vitamins, fats, cholesterol, phospholipids, and minerals
Wastes: Urea (nitrogenous waste)

Question 175

What are the three main proteins in plasma and what are their functions? Which protein is most abundant?

Answer 175

1) Albumins: smallest and most abundant
-Functions in maintaining osmotic pressure and transports hydrophobic substances
2) Globulins
-Alpha and beta: transports hydrophobic substances
-Gamma globulins = antibodies
3) Fibrinogen
-Fibrinogen can be converted to Fibrin (blood clot)

Question 176

Can you explain blood viscosity and what component of blood contributes most to the viscosity? What issue(s) arise if blood viscosity is too high or too low?

Answer 176

1) Defined as the resistance of a fluid to flow, resulting from the cohesion of its particles
2) RBCs affect blood viscosity; polycythemia and cause viscosity issues; anemia can cause viscosity issues.
3) An RBC or protein deficiency reduces viscosity and causes blood to flow too easily, whereas an excess causes blood to flow too sluggishly. Either of these conditions puts a strain on the heart that may lead to serious cardiovascular problems if not corrected.

Question 177

Can you define blood osmolarity? What issue(s) arise if blood osmolarity is too high or too low?

Answer 177

1) Osmolarity of blood: the total molarity of those dissolved particles that cannot pass through the blood vessel wall
2) If the blood osmolarity is too high, the bloodstream absorbs too much water. This raises the blood volume, resulting in high blood pressure and a potentially dangerous strain on the heart and arteries.
3) If its osmolarity drops too low, too much water remains in the tissues. They become edematous (swollen) and the blood pressure may drop to dangerously low levels because of the water lost from the bloodstream.

Question 178

Where does the production of blood originate?

Answer 178

Stem cells in red bone marrow

Question 179

1) Differentiate hematopoiesis from erythropoiesis.
2) Differentiate between myeloid hemopoiesis and lymphoid hemopoiesis.

Answer 179

1) Hemopoiesis is the creation of blood cells, and erythropoiesis is specifically the creation of red blood cells.
2) Blood formation in the bone marrow and lymphatic organs is called, respectively, myeloid and lymphoid hematopoiesis.

Question 180

Are you able to describe the structure and function of erythrocytes (red blood cells)? What gives the RBC it’s color?

Answer 180

1) Functions: To carry oxygen from the lungs to the tissues and to pick up and transport carbon dioxide from the tissues to the lungs.
2) Structure: They’re biconcave Discs with thick rim. Flexible; can change shape. No nucleus or organelles
3) Color: Nonprotein moiety (red-colored pigment) that binds O2 to ferrous ion (Fe) at the center of the heme groups

Question 181

Can you describe the structure of hemoglobin?

Answer 181

1) Four protein chains: globins
-Adult HB has two alpha and two beta chains
-Fetal Hb contains two alpha and two gamma chains
-Globins bind CO2 (5% of CO2 in blood)
2) Four heme groups
-Nonprotein moiety (red-colored pigment) that binds
-O2 to ferrous ion (Fe) at its center

Question 182

What is the function of hemoglobin?

Answer 182

1) O2 loading in lungs
Produces oxyhemoglobin (ruby red)
2) O2 unloading in tissues
Produces deoxyhemoglobin or reduced hemoglobin (dark red)
3) CO2 loading in tissues
20% of CO2 in blood binds to Hb; leads to carbaminohemoglobin

Question 183

What is the hematocrit range for men? For women? Why are the ranges for men and women different?

Answer 183

1) Values are lower in women:
-Normal levels of hematocrit for men range from 41% to 50%. Normal level for women is 36% to 48%
2) This is because:
-Androgens stimulate RBC production
-Women have periodic menstrual losses
-Hematocrit is inversely proportional to percentage of body fat

Question 184

Are you able to define clinical measurements as it relates to RBC and hemoglobin quantities? If a range is given regarding RBC and hemoglobin, whose values tend to be lower? Men or Women and why?

Answer 184

1) Ranges:
-Men’s normal ranges: RBCs: 4.6–6.2 x 1012/L Hemoglobin: 120–160 g/L
-Women normal ranges RBCs: 4.2–5.1 x 1012/L Hemoglobin: 120–160 g/L
2) Women’s RBC levels tend to be lower because:
-Androgens stimulate RBC production
-Women have periodic menstrual losses

Question 185

What hormone stimulates erythropoiesis and what organ produces the hormone? What was the stimulus for the hormone to be released?

Answer 185

1) Kidney production of erythropoietin stimulates bone marrow to perform erythropoiesis
2) Stimulus: A drop in RBC count causes hypoxemia detected by kidney; this could be due to:
-Low levels O2 (hypoxemia)
-High altitude
-Increase in exercise
-Loss of lung tissue in emphysema

Question 186

What is the life cycle of an erythrocyte, i.e what cell did it start from, and the stages until it is an erythrocyte? How long does it take?

Answer 186

1) Development of RBCs takes 3 to 5 days
1}) Reduction in cell size, increase in cell number, synthesis of hemoglobin, and loss of nucleus; first committed cell is called an erythrocyte colony-forming unit
2) Has receptors for erythropoietin (EPO) from kidneys
3) Erythroblasts (normoblast) multiply and synthesize hemoglobin
4) The nucleus is discarded to form a reticulocyte; named for fine network of endoplasmic reticulum
-0.5% to 1.5% of circulating RBCs are reticulocytes
5) Then matures to mature erythrocyte

Question 187

How long does a RBC circulate in the body on average? What is the significance of an increase in reticulocytes?

Answer 187

1) Up to 120 days
2) An increase in reticulocytes could indicate anemia due to red blood cells being destroyed earlier than normal (hemolytic anemia) Bleeding or a blood disorder in a fetus or newborn (erythroblastosis fetalis)

Question 188

Nutritionally, what is needed to perform erythropoiesis?

Answer 188

Iron, folic acid, vitamin B12, vitamin C

Question 189

Can you explain erythrocyte death and disposal? What organs are involved in the demise of the RBC? What happens to the heme of hemoglobin? What happens to the globin of hemoglobin? What happens to the iron that was involved?

Answer 189

1) RBCs rupture (hemolysis) in narrow channels of spleen and liver
2) Macrophages mainly in spleen but also in liver
3) Globins hydrolyzed into amino acids
4) Iron removed from heme and recycled
5) Heme pigment excreted
6) Heme pigment converted to biliverdin (green)
7) Biliverdin converted to(yellow)
8) Liver removes bilirubin (& biliverdin) and secretes into bile
9) Bile released into small intestine
10) Bacteria of large intestine convert pigments into urobilinogens

Question 190

Can you define gastroferritin, ferritin and transferrin? What element is bound to them and why does this element have to be bound?

Answer 190

In the stomach, Gastroferritin binds Fe^(2+) and transports it to small intestine
Absorbed into blood and binds to Transferrin for transport to bone marrow, liver, and other tissues
Stored in Liver as ferritin

Question 191

Define and describe polycythemia and its different types

Answer 191

1) Polycythemia: an excess of RBCs
2) Primary polycythemia: Cancer of erythropoietic cell line in red bone marrow
3) Secondary polycythemia: From dehydration, emphysema, high altitude, or physical conditioning
Increased blood volume, pressure, viscosity; can lead to embolism, stroke, or heart failure

Question 192

Define anemia and describe its 3 main causes and consequences

Answer 192

1) Anemia: a lack of RBCs
2) Causes: Inadequate erythropoiesis or hemoglobin synthesis due to things such as: Kidney failure, iron-deficiency anemia, pernicious anemia, hemorrhagic anemias from bleeding, hemolytic anemias from RBC destruction
3) Consequences:
-Tissue hypoxia and necrosis
-Patient is lethargic; shortness of breath; necrosis of brain, heart, or kidney
-Blood osmolarity is reduced, producing tissue edema
-Blood viscosity is low
-Pressure drops and heart race; cardiac failure may ensue

Question 193

Can you determine an incompatibility between a mother and fetus in Rh blood type?

Answer 193

Rh negative mother with anti-Rh antibodies, and baby with Rh positive blood

Question 194

Describe the different types of leukocytes

Answer 194

1) Neutrophils: acute infections, aggressively antibacterial
2) Eosinophils: parasitic infections and allergies, stain orange
3) Basophils: release histamines and heparin, stain purple
4) Lymphocytes: huge nucleus, b-cells and t-cells
5) Monocytes: chronic infections, viral infections and inflammation, leave blood stream and transform into macrophages

Question 195

1) What cell type did all the leukocytes begin with?
2) What is the significance of differentiating to a colony-forming unit?
3) Where does leukopoiesis start? Which leukocyte type migrates to the thymus?

Answer 195

1) Begin as Hemopoietic stem cells (HSCs) in the bone marrow
2) Each colony-forming unit develops into a particular type of WBC
3) T-lymphocytes migrate to the thymus

Question 196

What type of situations cause leukocyte disorders and include counts that are too high, too low, and/or cancerous? What are the scientific names of the leukocyte disorders as it relates to excess, deficiencies or cancer?

Answer 196

1) Leukopenia: low WBC count: below 5,000 WBCs/μL
-Causes: radiation, poisons, infectious disease
-Effects: elevated risk of infection
2) Leukocytosis: high WBC count: above 10,000 WBCs/μL
-Causes: infection, allergy, disease
3) Leukemia: cancer of hemopoietic tissue usually producing a very high number of abnormal, circulating leukocytes

Question 197

Can you describe the difference between a total WBC count and a differential WBC? Which is more useful and why?

Answer 197

Total WBC count is less useful than differential WBC count, because differential WBC count allows you to see which leukocyte type is abnormal

Question 198

Define hemostasis. How does the body control bleeding for small vessels?

Answer 198

Hemostasis—the cessation of bleeding
Vascular spasm: Vasoconstriction of a broken vessel

Question 199

Platelets are small fragments of cells called _________ and their function is to:

Answer 199

megakaryocytes; aid in clotting and stop bleeding

Question 200

Define thrombopoesis

Answer 200

The formation of platelets in bone marrow

Question 201

What are the three hemostatic mechanisms and which involve platelets? Of the three hemostatic mechanisms, which is the most immediate?

Answer 201

1) Vascular spasm, platelet plug formation, and blood clotting (coagulation); all 3 involve platelets
2) Vascular spasm is the most immediate protection against blood loss

Question 202

Describe vascular spasm

Answer 202

Most immediate protection against blood loss
Causes: Pain receptors, smooth muscle injury, platelets release serotonin (vasoconstrictor)
Vasoconstriction of a broken vessel

Question 203

Describe platelet plug formation

Answer 203

Intact vessels have a smooth endothelium coated with prostacyclin (platelet repellant)
Broken vessel exposes collagen
Platelet pseudopods stick to the collagen and to each other
Pseudopods contract - draw together a platelet plug
Platelets degranulate releasing chemicals that attracts more platelets
Positive feedback loop

Question 204

Describe blood clotting (coagulation)

Answer 204

last and most effective defense against bleeding
Conversion of fibrinogen into insoluble fibrin threads (framework of clot)
Procoagulants (clotting factors) in plasma
Activate one factor and it will activate the next to form a reaction cascade

Question 205

What is the last and most effective defense against bleeding?

Answer 205

Blood clotting/ coagulation

Question 206

Be able to differentiate between the extrinsic mechanism of coagulation and the intrinsic mechanism of coagulation.

Answer 206

1) Extrinsic pathway
-Factors released by damaged tissues
-Faster
2) Intrinsic pathway
-Initiated by platelets
-Slower

Question 207

Clotting factors are proteins produced by which organ? Is blood clotting a negative feedback mechanism or a positive feedback mechanism? What element is required?

Answer 207

1) Clotting factors are proteins produced by the liver
2) Blood clotting is a positive feedback mechanism
3) Calcium required for either pathway

Question 208

Whether extrinsic or intrinsic, they converge to the identical final three steps. Describe these steps

Answer 208

1) Factor x is converted to prothrombin activator
2) Prothrombin activator: Converts prothrombin to thrombin
3) Thrombin: Converts fibrinogen into fibrin monomers; monomers covalently bind to form fibrin polymer

Question 209

Define fibrinolysis. Why do you need fibrinolysis?

Answer 209

1) Fibrinolysis: dissolution of a clot, usually using plasmin (a fibrin-dissolving enzyme that breaks up the clot)
2) It’s needed because eventually the tissue is repaired and the clot is no longer needed

Question 210

What are the three mechanisms you have in the body that prevent inappropriate clotting?

Answer 210

1) Prostacyclin-coated endothelium repels platelets
2) Thrombin diluted and washed away by flowing blood
-Heart slowing in shock can result in clot formation
2) Natural anticoagulants
-Heparin (from basophils and mast cells)
-Antithrombin (from liver)

Question 211

Know the difference between the clotting disorders including hemophilia, thrombus and embolus. For a pulmonary embolism, where would the clot most likely originate from?

Answer 211

1) Hemophilia: family of hereditary diseases characterized by deficiencies of one factor or another
2) Thrombus: abnormal clotting in unbroken vessel
3) Embolus: anything that can travel in the blood and block blood vessels
-Infarction (tissue death) may occur; MI or stroke
4) Pulmonary embolism: 650,000 Americans die annually of thromboembolism; would originate from right heart (*)