Lecture Exam 3 -- Cardiovascular System Study Guide

Question 1

THE HEART –

What is the name for the study of the normal heart and diseases associated with it?

Answer 1

Cardiology

Question 2

THE HEART –

Where is the location of the heart?

Answer 2

just behind and slightly left of the breastbone

Question 3

THE HEART –

What is the name of the membrane that surrounds the heart?

Answer 3

pericardium

Question 4

THE HEART –

What are the layers of the heart wall?

Answer 4

Pericardium - membrane that surrounds the heart

Epicardium - The epicardium is the outer layer of the wall of the heart. It is composed of connective tissue covered by epithelium. The epicardium is also known as the visceral pericardium.

Myocardium - Myocardium is the muscular middle layer of the wall of the heart.

Endocardium - The endocardium is the inner layer of the heart. It consists of epithelial tissue and connective tissue.

Question 5

THE HEART –

Explain the major causes and symptoms of pericarditis.

Answer 5

Inflammation of pericardium (membrane that
surrounds heart).

Acute pericarditis - may be virally-induced.
chest pain that extends into left shoulder and left
arm. Can hear scratchy sound with stethoscope.

Lasts about a week and treated with acute antiinflammatory medication.

Question 6

THE HEART –

Why is the wall of the left ventricle thicker than the wall of the right ventricle?

Answer 6

The left ventricle needs to be thicker than the right because it needs to pump blood through the entire body.

The right ventricle only pumps to the lungs to oxygenate the blood

Question 7

HEART VALVES –

What is the purpose of heart valves?

Answer 7

In order for your heart to effectively pump blood it must open and close valves at different times during contraction so as to generate enough pressure to push blood through the vessels of your body.

Valves present in heart to ensure one way
flow of blood.

Question 8

HEART VALVES –

What stimulates heart valves to open and close?

Answer 8

pressure changes.

Question 9

HEART VALVES –
Where are the atrioventricular valves located? What are other names for the atrioventricular valves? Explain the mechanism of opening and closing of these valves.

Answer 9

• named because they occur between atrium
  and ventricles.
• The first one, on the right side of the heart, is called the Tricuspid Valve (it has three ‘flaps’). On the left side, the Atrioventricular Valve is called the Bicuspid or Mitral Valve (it has two ‘flaps’)
• when ventricles relaxed, papillary muscles
  relaxed, chordae tendinae slack - valve open.
• when ventricles contract - pressure of blood
  drives cusps upward, papillary muscles
  contract, chordae tendinae tighten - no
  backflow into atrium.

Question 10

HEART VALVES –

What is mitral stenosis?

Answer 10

narrowing of mitral (bicuspid

valve). (valve disorder)

Question 11

HEART VALVES –
Where are the pulmonary valves and aortic valves located? what do their structures
have in common?

Answer 11

• pulmonary valve - allows movement of
  blood from heart to pulmonary vessels but
  prevents backflow into right ventricle.
• aortic valve - allows movement from left
  ventricle to aorta and prevents backflow.

Both semilunar valves.

Question 12

CIRCULATORY SYSTEMS –

What is the systemic circulation? Which side of the heart is the pump for the systemic circulation?

Answer 12

Systemic circulation is the part of the cardiovascular system which carries oxygenated blood away from the heart to the body, and returns deoxygenated blood back to the heart

The pump for the sytemic circulation is on the left side.

Question 13

CIRCULATORY SYSTEMS –

What is the pulmonary circulation? Which side of the heart is the pump for the pulmonary circulation?

Answer 13

Pulmonary circulation is the portion of the cardiovascular system which carries deoxygenated blood away from the heart, to the lungs, and returns oxygenated (oxygen-rich) blood back to the heart

The pump for the pulmonary circulation is on the right side.

Question 14

CIRCULATORY SYSTEMS –

What is the coronary circulation? Where are the coronary vessels located?

Answer 14

Coronary circulation – blood supply to the myocardium.

When heart contracts very little blood flows to
coronary arteries.

When heart relaxed, high pressure blood in aorta
supplies coronary arteries.

Question 15

CIRCULATORY SYSTEMS –

Know the flow of blood through the systemic and pulmonary circulations as illustrated in Fig. 20.7.

Answer 15

1. Right Atrium: deoxygenated blood flows into the right atrium from the superior vena cava, inferior vena cava, and coronary sinus
2. Right Atrium => Right Ventricle through Tricuspid valve
3. Right ventricle => pulmonary trunk and pulmonary arteries through pulmonary valve
4. In pulmonary capillaries, blood loses CO2 and gains O2
5. Blood flows into the left atrium through the pulmonary veins
6. Left Atrium => Left ventricle through Bicuspid valve
7. Left ventricle => aorta and systemic arteries through the Aortic valve
8. Aorta and systemic arteries => systemic capillaries, where blood loses O2 and gains C02
9. Deoxygentated blood flows back to the right atrium through the superior vena cava, inferior vena cava, and coronary sinus

Question 16

CIRCULATORY SYSTEMS –

Explain the term: myocardial ischemia.

Answer 16

• partial obstruction of blood flow to coronary arteries.
• causes hypoxia (reduced oxygen supply).
• weakens heart muscle cells without killing
  them.

Question 17

CARDIAC MUSCLE TISSUE –

Describe the structural characteristics of cardiac muscle.

Answer 17

Similar to skeletal muscle but fibers:

• Shorter in length.
• Branch.
• Have central nucleus.
• Do not fuse but connect via intercalated discs.
• Numerous mitochondria.
• Same arrangement of actin and myosin as skeletal muscle.

Question 18

CARDIAC MUSCLE TISSUE –

What are intercalated discs?

Answer 18

Connect individual cardiac muscle fibers to one another.
Two types of junctions present:
Desmosomes - anchor cells together.
Gap junctions (communicating junctions) - allow action potentials to conduct from one cell to the next.

Question 19

CARDIAC MUSCLE TISSUE –

What is the function of desmosomes in the intercalated discs?

Answer 19

anchor cells together

Question 20

CARDIAC MUSCLE TISSUE –

What is the function of gap junctions in the intercalated discs?

Answer 20

allow action potentials to conduct from one

cell to the next.

Question 21

CARDIAC MUSCLE TISSUE –

Why are there many mitochondria in cardiac muscle tissue?

Answer 21

cardiac muscle produces most ATP by aerobic respiration - lots of mitochondria present.

Question 22

THE CONDUCTION SYSTEM –

What are autorhythmic fibers?

Answer 22

Cardiac muscle has ability to keep beating - even in isolation.

Some of the cells are “self-excitable” or autorhythmic.

Autorhythmic fibers generate action potentials
that trigger heart contractions.

Question 23

THE CONDUCTION SYSTEM –

Know the pathway through the conduction system.

Answer 23

1. Sinoatrial node: SA node cells are autorhythmic, meaning they spontaneously deporalize to threshold (spontaneous depolarization = pacemaker potential). When the pacemaker potential reaches threshold, it triggers and action potential, which propagates throughout both atria via gap junctions in the intercalated dists of atrial muscle fibers. Following the action potential, the atria contract.
2. The action potential reaches the atrioventricular node.
3. The action potential enters the AV node from the AV bundle (the bundle of His).
4. From the AV bundle, the action potential enters both the right and left bundle branches, which extend through the interventricular septum toward the apex of the heart.
5. Once the action potential reaches the apex, the purkinje fibers conduct the action potential upward to the remainder of the ventricular myocardium, causing the ventricles to contract.

Question 24

THE CONDUCTION SYSTEM –

What proportion of cardiac muscle cells are autorhythmic?

Answer 24

About 1% of the cardiac muscle fibers are

autorhythmic fibers.

Question 25

THE CONDUCTION SYSTEM -- | What does an artificial pacemaker achieve?

Answer 25

If synoatrial node (SA node)becomes damaged, activity of SA node and atrioventicular node (AV node) become slow. Can slow heart rate to 20-35 beats/min - inadequate to maintain blood supply to brain. Normal heart rhythm can be restored by surgical implantation of an artificial pacemaker - sends out small electrical signals to stimulate heart to contract.

Question 26

CARDIAC ACTION POTENTIALS -- | Where are cardiac action potentials initiated?

Answer 26

Action potential generated by sinoatrial node (SA node) and conducted by conduction system, spreads to "working" cardiac muscle fibers (contractile fibers).

Question 27

CARDIAC ACTION POTENTIALS -- What is different about the membrane potential of cells in the SA node compared to normal contractile cardiac muscle fibers?

Answer 27

Unlike autorhythmic fibers which have an unstable resting potential, contractile fibers have a stable resting potential of approx. -90mV

Question 28

CARDIAC ACTION POTENTIALS -- | What is a pacemaker potential?

Answer 28

SA node cells do not have stable resting potential and repeatedly depolarize spontaneously. Repeated depolarization generates pacemaker potentials. When pacemaker potentials reach a threshold depolarization an action potential is generated.

Question 29

CARDIAC ACTION POTENTIALS | What is the resting potential of contractile cardiac muscle fibers?

Answer 29

Approx -90mV

Question 30

CARDIAC ACTION POTENTIALS -- Once a threshold membrane potential is reached, what type of channels open to cause depolarization of the contractile fiber?

Answer 30

When a threshold depolarization is reached, voltage-gated sodium channels open in the sarcolemma of the contractile fiber.

Question 31

CARDIAC ACTION POTENTIALS -- | What is the cause of the long plateau phase in a contractile fiber action potential?

Answer 31

In cardiac muscle, the action potential is caused by opening of two types of channels: (1) the same fast sodium channels as those in skeletal muscle and (2) another entirely different population of slow calcium channels, which are also called calcium-sodium channels. This second population of channels differs from the fast sodium channels in that they are slower to open and, even more important, remain open for several tenths of a second. During this time, a large quantity of both calcium and sodium ions flows through these channels to the interior of the cardiac muscle fiber, and this maintains a prolonged period of depolarization, causing the plateau in the action potential.

Question 32

CARDIAC ACTION POTENTIALS -- What type of channels open and close in order to cause repolarization of a contractile fiber after an action potential has been generated?

Answer 32

Sodium ion channels close, then calcium ion channels close and potassium ion channels open. Outflow of potassium ions results in repolarization of membrane.

Question 33

CARDIAC ACTION POTENTIALS -- What is the advantage of a long refractory period before a second contraction can be initiated?

Answer 33

cardiac muscle cannot go into tetanus (stay contracted). This is necessary because the successful mechanism of heart is dependent on alternating contractions/relaxations of ventricles.

Question 34

CARDIAC ACTION POTENTIALS -- | Is the energy required for cardiac muscle contraction mostly provided by aerobic or anaerobic respiration?

Answer 34

Aerobic

Question 35

THE CARDIAC CYCLE -- | Define: Cardiac cycle

Answer 35

all the events associated with 1 heart beat

Question 36

THE CARDIAC CYCLE -- | Define: systole

Answer 36

phase of contraction

Question 37

THE CARDIAC CYCLE -- | Define: diastole

Answer 37

phase of relaxation

Question 38

THE CARDIAC CYCLE -- | Define: end diastolic volume

Answer 38

End diastolic volume (EDV)- the volume of blood | remaining in the ventricles at the end of diastole (about 130ml).

Question 39

THE CARDIAC CYCLE -- | Define: end systolic volume

Answer 39

End systolic volume (ESV) - the volume of blood | remaining in each ventricle at the end of systole (about 60ml in average healthy person).

Question 40

THE CARDIAC CYCLE -- | Define: stroke volume

Answer 40

The volume ejected per beat from the ventricle.

Question 41

THE CARDIAC CYCLE -- | Define: heart rate

Answer 41

the number of heart beats/min

Question 42

THE CARDIAC CYCLE -- | Define: cardiac output.

Answer 42

the volume of blood ejected by the left ventricle into the aorta (or the right ventricle into the pulmonary trunk).

Question 43

THE CARDIAC CYCLE -- | What is the relationship between cardiac output, stroke volume and heart rate?

Answer 43

Cardiac Output (ml/min) = Stroke Volume (ml/beat) X Heart Rate (beats/min)

Question 44

THE CARDIAC CYCLE -- What units would you use to report cardiac output, stroke volume and heart rate i.e. which is reported as ml/min or litres/min, which is reported as ml/beat and which is reported as beats/min? If you are provided with values for stroke volume and heart rate you should be able to calculate cardiac output.

Answer 44

Cardiac Output (ml/min) = Stroke Volume (ml/beat) X Heart Rate (beats/min)

Question 45

THE CARDIAC CYCLE -- | How do stress and exercise influence cardiac output?

Answer 45

``` Factors such as exercise and stress increase Stroke Volume (SV) and Heart Rate (HR) and therefore increase Cardiac Output (CO). ```

Question 46

THE CARDIAC CYCLE -- | What is cardiac reserve?

Answer 46

The cardiac reserve is the difference between a person's maximum Cardiac Output (CO) and their CO at rest. Cardiac reserve is 4-5 X resting value in average person. 7-8 X resting value in top athletes. People with heart disease may have little or no cardiac reserve.

Question 47

THE CARDIAC CYCLE -- | Name 3 factors that regulate stroke volume.

Answer 47

1) Preload - the degree of stretch in the heart before it contracts. 2) Contractility - the force of contraction of the muscle fibers. 3) Afterload - the pressure that must be exceeded in order to eject the blood from the ventricles.

Question 48

THE CARDIAC CYCLE -- | What is the Frank-Starling law of the heart?

Answer 48

Preload (the degree of stretch in the heart before it contracts.) is proportional to End Diastolic Volume (EDV - volume of blood that fills the heart at end of each diastole/relaxation). -- The greater the EDV the greater the next force of contraction.

Question 49

THE CARDIAC CYCLE -- | Name 2 factors that regulate end diastolic volume.

Answer 49

1) Duration of ventricular diastole. | 2) The volume of blood returning to the right ventricle.

Question 50

REGULATION OF FORCE AND RATE OF HEART CONTRACTION -- | Define the terms ionotropic and chronotropic.

Answer 50

Something that increases the force of contraction is called ionotropic. Something that increases the rate of contraction is called chronotropic.

Question 51

REGULATION OF FORCE AND RATE OF HEART CONTRACTION -- What effects do norepinephrine and epinephrine have on the force and rate of heart contraction (via sympathetic nerve activity)?

Answer 51

Increase heart rate and force of contraction

Question 52

REGULATION OF FORCE AND RATE OF HEART CONTRACTION -- What effect does the parasympathetic nervous system have on the force and rate of heart contraction?

Answer 52

Parasympathetic nervous system decreases heart rate and force of contraction via vagus nerve (cranial nerve X).

Question 53

REGULATION OF FORCE AND RATE OF HEART CONTRACTION -- | Via which cranial nerve do parasympathetic nerves reach the heart?

Answer 53

Cranial nerve X, the Vagus nerve

Question 54

REGULATION OF FORCE AND RATE OF HEART CONTRACTION -- | What do the terms tachycardia and bradycardia mean?

Answer 54

- tachycardia = increased resting heart rate | - bradycardia = decreased resting heart rate

Question 55

REGULATION OF FORCE AND RATE OF HEART CONTRACTION -- | What hormones regulate heart rate?

Answer 55

HR increased by norepinephrine and epinephrine from adrenal medulla. Also by thyroid hormones. People with hyperthyroidism (increased thyroid gland activity) show tachycardia (increased heart rate)

Question 56

THE CARDIOVASCULAR CENTER -- | Where in the brain is the cardiovascular centre located?

Answer 56

medulla oblongata

Question 57

THE CARDIOVASCULAR CENTER -- | What higher brain centers provide input to the cardiovascular center?

Answer 57

Nerve impulses descend from the cerebral cortex, limbic system, and hypothalamus to affect the cardiovascular center. Sympathetic Nervous System increases HR. Parasympathetic Nervous System decreases HR via vagus nerve (cranial nerve X)

Question 58

THE CARDIOVASCULAR CENTER -- | What sensory receptors provide input to the cardiovascular center?

Answer 58

Baroreceptors, Proprioceptors, Chemoreceptors. The three main types of sensory receptors that provide input to the cardiovascular center are proprioceptors, baroreceptors, and chemoreceptors. Proprioceptors monitor movements of joints and muscles and provide input to the cardiovascular center during physical activity. Their activity accounts for thee rapid increase in heart rate at the beginning of exercise. Baroreceptors monitor changes in pressure and stretch in the walls of blood vessels, and chemoreceptors monitor the concentration of various chemicals in the blood.

Question 59

HEART DISEASES -- What are the symptoms of congestive heart failure? What are possible causes of congestive heart failure? What symptoms would be expected if the left ventricle fails? What symptoms would be expected if the right ventricle fails?

Answer 59

Congestive heart failure is a chronic or acute state that results when the heart is not capable of supplying the oxygen demands of the body. • Causes of CHF – coronary artery disease, hypertension, MI, valve disorders, congenital defects • Left side heart failure – less effective pump so more blood remains in ventricle – heart is overstretched & even more blood remains – blood backs up into lungs as pulmonary edema – suffocation & lack of oxygen to the tissues • Right side failure – fluid builds up in tissues as peripheral edema

Question 60

HEART DISEASES -- What are the symptoms of coronary artery disease? What is an atherosclerotic plaque? What is a stent? What is cardiac bypass surgery?

Answer 60

Condition in which the heart muscle receives an inadequate amount of blood due to obstruction of its blood supply. It is the leading cause of death in the United States each year. The principal causes of obstruction include atherosclerosis, coronary artery spasm, or a clot in a coronary artery. Atherosclerotic plaque: Atherosclerosis is a process in which smooth muscle cells proliferate and fatty substances, especially cholesterol and triglycerides (neutral fats), accumulate in the walls of the medium-sized and large arteries in response to certain stimuli, such as endothelial damage Stent: A stent is a small mesh tube that's used to treat narrow or weak arteries Cardiac bypass surgery: Arteries or veins from elsewhere in the patient's body are grafted to the coronary arteries to bypass atherosclerotic narrowings and improve the blood supply to the coronary circulation supplying the myocardium (heart muscle)

Question 61

CAPILLARIES -- | Define: Capillaries

Answer 61

Capillaries are the site of exchange between the blood and the tissues.

Question 62

CAPILLARIES -- | What is the microcirculation?

Answer 62

Flow of blood through arterioles to capillaries to | venules called microcirculation.

Question 63

CAPILLARIES -- | Where are capillary sphincters located and what is there function?

Answer 63

The vessel between junction of arteriole and capillary called a metarteriole. Flow of blood at this point controlled by precapillary sphincters -a ring of smooth muscle that can contract or open.

Question 64

CAPILLARIES -- What are the names of the 3 types of capillaries? What are the differences in their structure? Which type of capillary is least permeable and which is most permeable?

Answer 64

• Continuous capillaries - least permeable – intercellular clefts are gaps between neighboring cells – skeletal & smooth, connective tissue and lungs • Fenestrated capillaries – plasma membranes have many holes – kidneys, small intestine, choroid plexuses, ciliary process & endocrine glands • Sinusoids - most permeable – very large fenestrations – incomplete basement membrane – liver, bone marrow, spleen, anterior pituitary, & parathyroid gland

Question 65

CAPILLARIES -- | Name 3 different methods of flow across capillary walls.

Answer 65

1) Diffusion 2) Transcytosis - through pinocytic vesicles 3) Bulk flow - large numbers of ions, molecules or particles moving together.

Question 66

CAPILLARIES -- | What governs the movement of material between tissues and blood and back? What is Starling’s law of capillaries?

Answer 66

Movement of material from blood to tissues and back governed by pressure differences. These pressure differences are kept close to equilibrium - called Starling’s Law of Capillaries.

Question 67

HEMODYNAMICS -- | Define the term hemodynamics.

Answer 67

factors affecting blood flow

Question 68

HEMODYNAMICS -- | What are the factors affecting blood flow?

Answer 68

Cardiac output depends on heart rate and stroke volume (the volume ejected per beat from the ventricle). However the flow to different tissues will vary dependent on: a) The pressure difference that drives blood through the tissues. b) the resistance to blood flow in different vessels The pressure differences that drives blood through tissues and the resistance to blood flow in different tissues will influence blood flow to different parts of the body.

Question 69

BLOOD PRESSURE -- | Define: Blood pressure

Answer 69

BP - generated by contraction of ventricles | Defined as the hydrostatic pressure exerted by blood on the walls of blood vessels.

Question 70

BLOOD PRESSURE -- | Define: systolic blood pressure

Answer 70

highest blood pressure obtained in arteries during systole (atrial and ventricular contraction)

Question 71

BLOOD PRESSURE -- | Define: diastolic blood pressure

Answer 71

lowest arterial blood pressure during diastole (atrial and ventricular relaxation).

Question 72

BLOOD PRESSURE -- | Define: mean arterial pressure

Answer 72

average blood pressure over course of a cardiac cycle

Question 73

BLOOD PRESSURE -- | Define: systemic vascular resistance.

Answer 73

Systemic vascular resistance (SVR) = sum of all resistances of systemic blood vessels. Controlled by vascular control center in brain.

Question 74

BLOOD PRESSURE -- | Name 3 factors that influence systemic vascular resistance.

Answer 74

1) Size of lumen of vessel 2) Blood viscosity 3) Blood vessel length

Question 75

BLOOD PRESSURE -- | Where are baroreceptors located? How do they regulate blood pressure?

Answer 75

Baroreceptors, pressure-sensitive sensory receptors, are located in the aorta, internal carotid arteries (arteries in the neck that supply blood to the brain), and other large arteries in the neck and chest. They send impulses to the cardiovascular center to help regulate blood pressure.

Question 76

HORMONAL REGULATION OF BLOOD PRESSURE -- How do the following hormones influence blood pressure? Renin-angiotensin-aldosterone system

Answer 76

Renin-angiotensin-aldosterone system - renin secreted by kidneys in response to decreased blood flow. Stimulates Angiotensin II which is a vasoconstrictor and stimulates secretion of aldosterone from adrenal cortex. Aldosterone in turn acts on kidneys to increase water reabsorption.

Question 77

HORMONAL REGULATION OF BLOOD PRESSURE -- How do the following hormones influence blood pressure? Epinephrine and norepinephrine

Answer 77

Increase blood pressure

Question 78

HORMONAL REGULATION OF BLOOD PRESSURE -- How do the following hormones influence blood pressure? Antidiuretic hormone

Answer 78

released from posterior pituitary. Acts on kidney to | increase water reabsorption and constricts blood vessels.

Question 79

HORMONAL REGULATION OF BLOOD PRESSURE How do the following hormones influence blood pressure? Atrial natriuretic peptide

Answer 79

produced by atria of heart. Lowers blood pressure by promoting loss of salt and water by kidneys (opposite effect to ADH and aldosterone).

Question 80

RESTORATION OF NORMAL BLOOD PRESSURE FOLLOWING BLOOD LOSS. -- Understand the physiological pathways that are set in motion to restore a fall in blood pressure.

Answer 80

When blood pressure falls, the baroreceptors are stretched less, and they send nerve impulses at a slower rate to the cardiovascular center. In response, the CV center decreases parasympathetic stimulation of the heart by way of motor axons of the vagus nerves and increases sympathetic stimulation of the heart via cardiac accelerator nerves. Another consequence of increased sympathetic stimulation is increased secretion of epinephrine and norepinephrine by the adrenal medulla. As the heart beats faster and more forcefully, and as systemic vascular resistance increases, cardiac output and systemic vascular resistance rise, and blood pressure increases to the normal level.

Question 81

THE HEART -- | Explain the major causes and symptoms of myocarditis.

Answer 81

Inflammation of myocardium (middle muscular layer of heart wall). - often due to complication of viral infection -usually mild.

Question 82

THE HEART -- | Explain the major causes and symptoms of endocarditis.

Answer 82

Inflammation of the endocardium (inner layer of heart wall). - usually involves heart valves. - most cases caused by bacteria. - signs include fever, heart murmur (noise between or after regular heart sounds), irregular, rapid heart beat. - Treated with antibiotics.

Question 83

CIRCULATORY SYSTEMS -- | Explain the term: angina pectoris.

Answer 83

Literally means "strangled chest" - severe pain that accompanies myocardial ischemia.

Question 84

CIRCULATORY SYSTEMS -- | Explain the term: myocardial infarction.

Answer 84

Heart Attack -- - complete obstruction of blood flow to coronary arteries. - Infarction means death because heart muscle that receives no oxygen dies. - May cause sudden death by causing ventricular fibrillation (asynchronous contractions of ventricles) - Heart muscle can remain alive if receives as little as 10-15% of normal blood supply.