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Bio 40B > Lecture Exam 3 -- Cardiovascular System Study Guide > Flashcards

Lecture Exam 3 -- Cardiovascular System Study Guide Flashcards

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1
Q

THE HEART –

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

A

Cardiology

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2
Q

THE HEART –

Where is the location of the heart?

A

just behind and slightly left of the breastbone

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3
Q

THE HEART –

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

A

pericardium

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4
Q

THE HEART –

What are the layers of the heart wall?

A

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.

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5
Q

THE HEART –

Explain the major causes and symptoms of pericarditis.

A

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.

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6
Q

THE HEART –

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

A

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

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7
Q

HEART VALVES –

What is the purpose of heart valves?

A

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.

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8
Q

HEART VALVES –

What stimulates heart valves to open and close?

A

pressure changes.

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9
Q

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.

A
  • 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.
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10
Q

HEART VALVES –

What is mitral stenosis?

A

narrowing of mitral (bicuspid

valve). (valve disorder)

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11
Q

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

A
  • 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.

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12
Q

CIRCULATORY SYSTEMS –

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

A

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.

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13
Q

CIRCULATORY SYSTEMS –

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

A

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.

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14
Q

CIRCULATORY SYSTEMS –

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

A

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.

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15
Q

CIRCULATORY SYSTEMS –

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

A
  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
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16
Q

CIRCULATORY SYSTEMS –

Explain the term: myocardial ischemia.

A
  • partial obstruction of blood flow to coronary arteries.
  • causes hypoxia (reduced oxygen supply).
  • weakens heart muscle cells without killing
    them.
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17
Q

CARDIAC MUSCLE TISSUE –

Describe the structural characteristics of cardiac muscle.

A

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.
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18
Q

CARDIAC MUSCLE TISSUE –

What are intercalated discs?

A

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.

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19
Q

CARDIAC MUSCLE TISSUE –

What is the function of desmosomes in the intercalated discs?

A

anchor cells together

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20
Q

CARDIAC MUSCLE TISSUE –

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

A

allow action potentials to conduct from one

cell to the next.

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21
Q

CARDIAC MUSCLE TISSUE –

Why are there many mitochondria in cardiac muscle tissue?

A

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

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22
Q

THE CONDUCTION SYSTEM –

What are autorhythmic fibers?

A

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.

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23
Q

THE CONDUCTION SYSTEM –

Know the pathway through the conduction system.

A
  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.
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24
Q

THE CONDUCTION SYSTEM –

What proportion of cardiac muscle cells are autorhythmic?

A

About 1% of the cardiac muscle fibers are

autorhythmic fibers.

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25
Q

THE CONDUCTION SYSTEM –

What does an artificial pacemaker achieve?

A

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.

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26
Q

CARDIAC ACTION POTENTIALS –

Where are cardiac action potentials initiated?

A

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

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27
Q

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

A

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

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28
Q

CARDIAC ACTION POTENTIALS –

What is a pacemaker potential?

A

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.

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29
Q

CARDIAC ACTION POTENTIALS

What is the resting potential of contractile cardiac muscle fibers?

A

Approx -90mV

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30
Q

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

A

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

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31
Q

CARDIAC ACTION POTENTIALS –

What is the cause of the long plateau phase in a contractile fiber action potential?

A

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.

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32
Q

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?

A

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

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33
Q

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

A

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.

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34
Q

CARDIAC ACTION POTENTIALS –

Is the energy required for cardiac muscle contraction mostly provided by aerobic or anaerobic respiration?

A

Aerobic

35
Q

THE CARDIAC CYCLE –

Define: Cardiac cycle

A

all the events associated with 1 heart beat

36
Q

THE CARDIAC CYCLE –

Define: systole

A

phase of contraction

37
Q

THE CARDIAC CYCLE –

Define: diastole

A

phase of relaxation

38
Q

THE CARDIAC CYCLE –

Define: end diastolic volume

A

End diastolic volume (EDV)- the volume of blood

remaining in the ventricles at the end of diastole (about 130ml).

39
Q

THE CARDIAC CYCLE –

Define: end systolic volume

A

End systolic volume (ESV) - the volume of blood

remaining in each ventricle at the end of systole (about 60ml in average healthy person).

40
Q

THE CARDIAC CYCLE –

Define: stroke volume

A

The volume ejected per beat from the ventricle.

41
Q

THE CARDIAC CYCLE –

Define: heart rate

A

the number of heart beats/min

42
Q

THE CARDIAC CYCLE –

Define: cardiac output.

A

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

43
Q

THE CARDIAC CYCLE –

What is the relationship between cardiac output, stroke volume and heart rate?

A

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

44
Q

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.

A

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

45
Q

THE CARDIAC CYCLE –

How do stress and exercise influence cardiac output?

A 
Factors such as exercise and stress increase
Stroke Volume (SV) and Heart Rate (HR) and therefore increase Cardiac Output (CO).
46
Q

THE CARDIAC CYCLE –

What is cardiac reserve?

A

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.

47
Q

THE CARDIAC CYCLE –

Name 3 factors that regulate stroke volume.

A

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.

48
Q

THE CARDIAC CYCLE –

What is the Frank-Starling law of the heart?

A

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.

49
Q

THE CARDIAC CYCLE –

Name 2 factors that regulate end diastolic volume.

A

1) Duration of ventricular diastole.

2) The volume of blood returning to the right ventricle.

50
Q

REGULATION OF FORCE AND RATE OF HEART CONTRACTION –

Define the terms ionotropic and chronotropic.

A

Something that increases the force of contraction is called ionotropic.

Something that increases the rate of contraction is called chronotropic.

51
Q

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)?

A

Increase heart rate and force of contraction

52
Q

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

A

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

53
Q

REGULATION OF FORCE AND RATE OF HEART CONTRACTION –

Via which cranial nerve do parasympathetic nerves reach the heart?

A

Cranial nerve X, the Vagus nerve

54
Q

REGULATION OF FORCE AND RATE OF HEART CONTRACTION –

What do the terms tachycardia and bradycardia mean?

A
  • tachycardia = increased resting heart rate

- bradycardia = decreased resting heart rate

55
Q

REGULATION OF FORCE AND RATE OF HEART CONTRACTION –

What hormones regulate heart rate?

A

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)

56
Q

THE CARDIOVASCULAR CENTER –

Where in the brain is the cardiovascular centre located?

A

medulla oblongata

57
Q

THE CARDIOVASCULAR CENTER –

What higher brain centers provide input to the cardiovascular center?

A

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)

58
Q

THE CARDIOVASCULAR CENTER –

What sensory receptors provide input to the cardiovascular center?

A

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.

59
Q

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?

A

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

60
Q

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

A

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)

61
Q

CAPILLARIES –

Define: Capillaries

A

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

62
Q

CAPILLARIES –

What is the microcirculation?

A

Flow of blood through arterioles to capillaries to

venules called microcirculation.

63
Q

CAPILLARIES –

Where are capillary sphincters located and what is there function?

A

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.

64
Q

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?

A

• 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

65
Q

CAPILLARIES –

Name 3 different methods of flow across capillary walls.

A

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

66
Q

CAPILLARIES –

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

A

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.

67
Q

HEMODYNAMICS –

Define the term hemodynamics.

A

factors affecting blood flow

68
Q

HEMODYNAMICS –

What are the factors affecting blood flow?

A

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.

69
Q

BLOOD PRESSURE –

Define: Blood pressure

A

BP - generated by contraction of ventricles

Defined as the hydrostatic pressure exerted by blood on the walls of blood vessels.

70
Q

BLOOD PRESSURE –

Define: systolic blood pressure

A

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

71
Q

BLOOD PRESSURE –

Define: diastolic blood pressure

A

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

72
Q

BLOOD PRESSURE –

Define: mean arterial pressure

A

average blood pressure over course of a cardiac cycle

73
Q

BLOOD PRESSURE –

Define: systemic vascular resistance.

A

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

74
Q

BLOOD PRESSURE –

Name 3 factors that influence systemic vascular resistance.

A

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

75
Q

BLOOD PRESSURE –

Where are baroreceptors located? How do they regulate blood pressure?

A

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.

76
Q

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

A

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.

77
Q

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

A

Increase blood pressure

78
Q

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

A

released from posterior pituitary. Acts on kidney to

increase water reabsorption and constricts blood vessels.

79
Q

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

A

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

80
Q

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

A

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.

81
Q

THE HEART –

Explain the major causes and symptoms of myocarditis.

A

Inflammation of myocardium (middle muscular layer of heart wall).

  • often due to complication of viral infection -usually mild.
82
Q

THE HEART –

Explain the major causes and symptoms of endocarditis.

A

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.
83
Q

CIRCULATORY SYSTEMS –

Explain the term: angina pectoris.

A

Literally means “strangled chest”

  • severe pain that accompanies myocardial
    ischemia.
84
Q

CIRCULATORY SYSTEMS –

Explain the term: myocardial infarction.

A

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.

Bio 40B (12 decks)

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