Module 1: Heart Flashcards
(174 cards)
1
Q
A
2
Q
What are the functions of the lymphatic system?
A
The lymphatic system has several functions including:
* Fluid recovery
* Immune response
* Lipid absorption
3
Q
What organs or tissues are part of the lymphatic system?
A
The organs and tissues of the lymphatic system include:
* Lymph nodes
* Spleen
* Thymus
* Bone marrow
* Lymphatic vessels
4
Q
Where is the lymphatic system located within the body?
A
The lymphatic system is distributed throughout the body, with lymphatic vessels running parallel to blood vessels and lymph nodes located at various points.
5
Q
What are the characteristics and roles of lymphatic vessels?
A
Lymphatic vessels are:
* Thin-walled
* Valved
* Transport lymph fluid back to the bloodstream
* Help maintain fluid balance
6
Q
What is the role of lymph nodes?
A
Lymph nodes filter lymph fluid, trapping pathogens and foreign substances, and are sites for immune cell activation.
7
Q
Describe the role of the lymphatic system in microcirculation and fluid recovery.
A
The lymphatic system collects excess interstitial fluid, returns it to the bloodstream, and helps maintain tissue fluid balance.
8
Q
Define edema.
A
Edema is the abnormal accumulation of fluid in the interstitial spaces of tissues.
9
Q
What are the four main causes of edema?
A
The four main causes of edema are:
* Increased hydrostatic pressure
* Decreased oncotic pressure
* Increased capillary permeability
* Lymphatic obstruction
10
Q
What is the structure and role of the pericardium?
A
The pericardium is a double-walled sac surrounding the heart, consisting of:
* Visceral pericardium
* Parietal pericardium
It protects the heart and allows it to contract with minimal friction.
11
Q
Identify the layers of the heart.
A
The layers of the heart are:
* Epicardium
* Myocardium
* Endocardium
12
Q
What chambers are found in the heart?
A
The heart contains:
* Left atrium
* Right atrium
* Left ventricle
* Right ventricle
13
Q
What are the types of valves in the heart?
A
The heart has:
* Right atrioventricular (AV) valve (Tricuspid valve)
* Left atrioventricular (AV) valve (Bicuspid/Mitral valve)
* Semilunar valves (Pulmonary and Aortic valves)
14
Q
Define cardiomyocytes.
A
Cardiomyocytes are specialized muscle cells of the heart that contract to pump blood.
15
Q
What are the histological components of cardiac muscle?
A
Cardiac muscle is characterized by:
* Striated appearance
* Intercalated discs
* Single nucleus per cell
* Myofibrils
16
Q
What is the function of intercalated discs?
A
Intercalated discs connect cardiomyocytes, enabling synchronized contraction and electrical signal transmission.
17
Q
Describe the role of desmosomes and gap junctions in cardiac muscle.
A
Desmosomes provide mechanical strength, while gap junctions allow for electrical coupling and ion movement between cells.
18
Q
What is the cardiac conduction system?
A
The cardiac conduction system is a network of specialized cells that initiate and propagate action potentials throughout the heart.
19
Q
What is the significance of a positive inotropic stimulus?
A
A positive inotropic stimulus increases the end-diastolic volume (EDV), decreases the end-systolic volume (ESV), leading to increased stroke volume (SV) and cardiac output (CO).
20
Q
What are the phases of the myocyte action potential?
A
The phases of the myocyte action potential include:
* Phase 0: Depolarization
* Phase 1: Initial repolarization
* Phase 2: Plateau
* Phase 3: Repolarization
* Phase 4: Resting potential
21
Q
What ions are involved in the cardiac myocyte action potential?
A
The main ions involved are:
* Sodium (Na+)
* Calcium (Ca2+)
* Potassium (K+)
22
Q
What distinguishes nodal (non-contractile) cells from contractile cells?
A
Nodal cells spontaneously generate action potentials and do not have a stable resting membrane potential, unlike contractile myocytes.
23
Q
What is the role of the SA Node?
A
The SA Node is the primary pacemaker of the heart, initiating action potentials that regulate heart rate.
24
Q
What happens during the plateau phase of the myocyte action potential?
A
During the plateau phase, calcium channels remain open, allowing calcium ions to enter the cell, prolonging depolarization.
25
What is the absolute refractory period?
The absolute refractory period is the time during which a second action potential cannot be initiated, regardless of stimulus strength.
26
What is the relative refractory period?
The relative refractory period is the time during which a second action potential can be initiated, but requires a stronger-than-normal stimulus.
27
What stimulates the opening of calcium ion voltage-gated channels?
Depolarization phase of the action potential
## Footnote
Depolarization phase typically occurs at -40 mV
28
What are the two types of calcium channels involved in nodal cell action potential?
* T-type Calcium (Ca2+) channels
* L-type Calcium (Ca2+) channels
29
What phase of the nodal cell action potential involves the opening of potassium (K+) voltage-gated channels?
Phase 3
30
At what voltage is the cell fully repolarized during the nodal cell action potential?
-60 mV
31
What is the significance of Phase 4 of the nodal cell action potential?
It allows sodium, calcium, and potassium ions to move into the nodal cells
32
What determines the heart rate?
The rate of spontaneous depolarization
33
What are the structural components within the sarcoplasm of a myocyte?
* Myosin
* Actin
* Tropomyosin
* Troponin
34
What is the importance of Phase 2 of the myocyte action potential?
It is crucial for cardiac muscle contraction
35
What is the role of calcium ions in muscle contraction?
Calcium ions enter the myocyte and bind to troponin to initiate contraction
36
How does the intracellular calcium ion concentration affect myocyte contraction force?
It is directly proportional to the force of contraction
37
What mechanisms are necessary for cardiac muscle relaxation?
* Nodal cells must stop action potential generation
* Calcium ions must be pumped back into the sarcoplasmic reticulum and/or extracellular fluid
38
What are the terms that describe the effects on heart function?
* Chronotropic
* Dromotropic
* Inotropic
39
What is the effect of the sympathetic nervous system on heart rate?
Positive chronotropic effects increase heart rate
40
What is the effect of the parasympathetic nervous system on heart rate?
Negative chronotropic effects decrease heart rate
41
What does an electrocardiogram (ECG) measure?
Tiny potential differences that reflect the electrical activity of the heart
42
What is the function of the sinoatrial (SA) node?
It determines the heart rate as the pacemaker
43
What is the role of the atrioventricular (AV) node?
It serves as an electrical relay system and slows the electrical impulse before allowing it to pass to the ventricles
44
What is the significance of the conduction velocity in the cardiac conduction system?
It determines how long it takes the action potential to spread throughout the myocardium
45
What happens during Phase 2 of the myocyte action potential?
Calcium ions enter the cell through L-Type Voltage Gated Calcium channels
46
True or False: Cardiac muscle has the same myofilaments as skeletal muscle.
True
47
What happens if the inward calcium ions during the plateau phase are insufficient?
Muscle contraction will not be stimulated
48
What is the measurement of tiny potential differences on the surface of the body that reflects the electrical activity of the heart?
Electrocardiogram (EKG)
## Footnote
An electrocardiogram is a graphical representation of the electrical activity of the heart over time.
49
What can an EKG tell us about heart activity?
Heart rate, rhythm, myocyte damage, nodal dysfunction
## Footnote
These parameters help assess the health and function of the heart.
50
What is the sequence of contraction in the heart?
Atria contract first, then ventricles contract
## Footnote
Atria depolarize before ventricles, and ventricles depolarize in a specific sequence.
51
What are the main components of an EKG graph?
P Wave, QRS Complex, T Wave, PR Interval, QT Interval, QRS Interval, PR (or PQ) Segment, ST Segment
## Footnote
Each component corresponds to specific electrical activities and contractions in the heart.
52
What does the P Wave represent in an EKG?
Atrial Depolarization
## Footnote
It indicates the electrical impulse traveling through the atria.
53
What does the QRS Complex represent in an EKG?
Ventricular Depolarization
## Footnote
This complex shows the electrical impulse traveling through the ventricles.
54
What does the T Wave represent in an EKG?
Ventricular Repolarization
## Footnote
It reflects the recovery phase of the ventricles after contraction.
55
What is sinus rhythm?
Normal heartbeat originating from the SA node
## Footnote
It must meet three criteria regarding rate and timing of impulses.
56
What are the criteria for sinus rhythm?
1. AP must originate in the SA node
2. SA nodal impulses must occur regularly at a rate of 60–100 impulses per minute
3. Activation of the myocardium must occur correctly
## Footnote
These criteria ensure proper heart function.
57
What is heart arrhythmia?
Cardiac conduction system dysfunction causing abnormal contractions
## Footnote
It can lead to rapid, slow, or irregular heartbeats.
58
What is the basic equation for blood flow in hemodynamics?
Blood Flow = Pressure / Resistance
## Footnote
This equation illustrates the relationship between pressure difference, resistance, and blood flow.
59
What is mean arterial pressure (MAP)?
Average arterial pressure throughout one cardiac cycle
## Footnote
It ensures blood flow to tissues and is calculated as MAP = Diastolic Pressure + (Pulse Pressure/3).
60
What is pulse pressure?
Difference between systolic and diastolic blood pressure
## Footnote
It indicates the force exerted on arterial walls during heartbeats.
61
What are the three layers of blood vessels?
Tunica Externa, Tunica Media, Tunica Interna
## Footnote
These layers serve different structural and functional roles in blood vessels.
62
What type of blood vessels carry blood away from the heart?
Arteries
## Footnote
They typically transport oxygenated blood and have thicker walls to withstand higher pressure.
63
What are capillaries primarily responsible for?
Nutrient and waste exchange
## Footnote
They consist only of endothelium and allow for the exchange of gases, nutrients, and solutes.
64
What are the three types of capillaries?
1. Continuous Capillaries
2. Fenestrated Capillaries
3. Sinusoids
## Footnote
Each type has distinct structures and functions in terms of permeability.
65
What is the primary function of erythrocytes (RBCs)?
Carry oxygen
## Footnote
They contain hemoglobin, which binds oxygen for transport.
66
What are the components of blood?
Formed Elements (Blood Cells) and Plasma
## Footnote
Formed elements include erythrocytes, leukocytes, and thrombocytes.
67
What role do leukocytes (WBCs) play in the body?
Immunity function
## Footnote
They are crucial for the immune response against pathogens.
68
What is the role of albumin in plasma?
Transport molecules and maintain osmotic pressure
## Footnote
It helps keep fluid in the bloodstream and regulates blood volume.
69
What are the three main components of blood?
Electrolytes, glucose, hormones
## Footnote
Plasma proteins make up 7% of blood components.
70
What is the most abundant plasma protein?
Albumin
## Footnote
Albumin is made by the liver.
71
What is the primary function of albumin in the blood?
Helps to transport molecules and maintains osmotic pressure
## Footnote
It holds water inside blood vessels.
72
What percentage of plasma proteins do globulins account for?
38%
## Footnote
Includes alpha, beta, and gamma globulins.
73
What is the role of gamma globulins?
Involved in immunity, commonly known as antibodies.
74
What percentage of plasma proteins does fibrinogen constitute?
8%
## Footnote
Necessary for blood clotting.
75
What is the flow sequence of blood in the heart?
Atria contract then ventricles contract.
76
What is the purpose of the pulmonary circuit?
Transports deoxygenated blood to the lungs for gas exchange.
77
What is the role of the left atrium?
Receives oxygenated blood from the pulmonary circuit.
78
What valve does blood pass through from the left atrium to the left ventricle?
Left Atrioventricular Valve (Bicuspid, Mitral valve).
79
What is the function of the aorta?
Transports oxygenated blood to the systemic circuit.
80
What type of blood does the right atrium receive?
Deoxygenated blood from the systemic circuit.
81
What valve does blood pass through from the right atrium to the right ventricle?
Right Atrioventricular Valve (Tricuspid).
82
What is the main function of arterioles?
Regulate blood flow and pressure.
83
What are the three main variables affecting peripheral resistance?
Blood viscosity, vessel length, vessel radius.
84
What is blood viscosity?
Thickness of fluids affecting their ability to flow.
85
How does vessel length affect resistance?
Longer vessels increase resistance and decrease blood flow.
86
What is the most significant factor affecting resistance in blood flow?
Blood vessel radius.
87
What is the role of the vasomotor center?
Regulates blood pressure through sympathetic control.
88
What do baroreceptors do?
Provide input regarding changes in blood pressure.
89
What is the role of chemoreceptors?
Adjust respiration rate and provide vasomotor influences.
90
What hormone promotes sodium reabsorption in the kidneys?
Aldosterone.
91
What is the function of antidiuretic hormone (ADH)?
Regulates plasma osmolarity by promoting water reabsorption.
92
What does increased blood viscosity do to blood flow?
Increases resistance and decreases blood flow.
93
What is the formula for mean arterial pressure (MAP)?
MAP = Diastolic + (Pulse Pressure/3).
94
What is the normal range for blood pressure?
120 mm Hg / 80 mm Hg.
95
Fill in the blank: Blood pressure is measured in _______.
mm Hg.
96
True or False: Blood pressure decreases during diastole.
True.
97
What is the primary function of vasopressin?
Assists in the regulation of plasma osmolarity and stimulates the collecting duct in the kidneys to reabsorb water
98
Where is vasopressin produced and stored?
Produced by the hypothalamus and stored in the posterior pituitary
99
What triggers the secretion of vasopressin?
Secreted in response to hypertonic or hypotonic blood plasma
100
What effect does ANP (Atrial Natriuretic Peptide) have on blood pressure?
Reduces arterial pressure by decreasing blood volume and systemic peripheral resistance
101
What does increased atrial stretch in myocytes indicate?
It indicates increased blood volume or pressure in the atria
102
What are catecholamines?
Hormones that bind to adrenergic receptors on smooth muscle of most blood vessels
103
What effect do catecholamines have on blood pressure?
Causes vasoconstriction, leading to increased blood pressure
104
What is the role of Angiotensin II in blood pressure regulation?
Stimulates the release of aldosterone, increases thirst, and activates the sympathetic nervous system
105
Name the important molecules in the Renin-Angiotensin-Aldosterone System (RAAS)
* Renin
* Angiotensinogen
* Angiotensin I
* Angiotensin II
* Angiotensin converting enzyme (ACE)
* Aldosterone
106
What triggers renin secretion?
Renal artery hypotension and decreased sodium within the distal tubules of the kidney
107
What is the function of renin?
Converts Angiotensinogen to Angiotensin I
108
What does angiotensin converting enzyme (ACE) do?
Converts Angiotensin I to Angiotensin II
109
What happens to blood pressure as compliance of a blood vessel decreases?
Blood pressure increases
110
What is the cardiac cycle?
All the events, mechanical and electrical, that occur in one complete contraction and relaxation of the heart chambers
111
What does systole refer to?
The part of the cardiac cycle when contraction is occurring
112
What does diastole refer to?
The part of the cardiac cycle when contraction is not occurring
113
What is stroke volume (SV)?
Amount of blood ejected from each ventricle during ventricular contraction
114
What is end diastolic volume (EDV)?
The volume of blood in the ventricles right before contraction
115
What is end systolic volume (ESV)?
The volume of blood in the ventricles right after contraction
116
What occurs during isovolumetric contraction?
Ventricles contract with no change to the volume of blood in the ventricles
117
What occurs during isovolumetric relaxation?
Ventricles relax with no change to the volume of blood in the ventricles
118
What is the significance of the S1 heart sound?
It is produced by the closing of the AV valves during isovolumetric contraction
119
What is the significance of the S2 heart sound?
It is produced by the closing of the semilunar valves during isovolumetric relaxation
120
During which phase does rapid ventricular ejection occur?
During ventricular systole when blood is rapidly pushed out of the ventricles
121
What happens when ventricular pressure falls below atrial pressure?
Blood rushes from the atria into the ventricles
122
What is the relationship between pressure and volume in the cardiac cycle?
As volume decreases, pressure decreases; as volume increases, pressure increases
123
Which part of the ECG correlates with atrial systole?
P wave
124
What is the effect of hypoxia on blood vessels?
Hypoxia leads to vasodilation
125
How do baroreceptors maintain appropriate MAP?
They detect mean arterial pressure and adjust blood pressure accordingly
126
Aldosterone causes the excretion of sodium ions and the reabsorption of potassium ions in the kidneys. True or False?
B. False
127
How does ADH cause increased blood pressure?
Increases water retention within the kidneys and leads to increased blood volume
128
What is the role of the molecules in the RAAS?
Regulate blood pressure through various mechanisms including vasoconstriction and fluid retention
129
Define the term cardiac cycle
The sequence of events in the heart from the beginning of one heartbeat to the beginning of the next heartbeat
## Footnote
The cardiac cycle includes phases of contraction and relaxation of the heart chambers.
130
Identify the steps to the cardiac cycle
1. Atrial Systole
2. Isovolumetric Contraction
3. Ventricular Systole
4. Isovolumetric Relaxation
5. Ventricular Diastole
131
Describe the actions and processes occurring in isovolumetric contraction
All valves are closed, ventricular pressure rises, and the myocytes contract without changing the volume of blood in the ventricles.
132
What is the relationship between the cardiac cycle and the electrocardiogram?
Each step of the cardiac cycle corresponds to distinct waves and intervals on the electrocardiogram.
133
Describe unique characteristics of isovolumetric relaxation
All valves are closed, ventricular pressure decreases, and the volume remains constant as the heart prepares for filling.
134
Identify when end diastolic volume occurs
End diastolic volume occurs at the end of ventricular filling, just before ventricular contraction.
135
Identify when end systolic volume occurs
End systolic volume occurs at the end of ventricular contraction, just before the ventricles begin to refill.
136
When do heart sounds occur within the cardiac cycle?
Heart sounds occur during the closing of valves: 'lub' (S1) during isovolumetric contraction and 'dub' (S2) during isovolumetric relaxation.
137
Define the term cardiac output
The amount of blood pumped from each ventricle in one minute.
138
How is cardiac output calculated?
Cardiac Output = Stroke Volume x Heart Rate.
139
What are the three major variables that influence stroke volume?
1. Preload
2. Contractility
3. Afterload
140
Describe how preload influences stroke volume
Preload is the stretch on the ventricles prior to contraction; greater preload increases stroke volume.
141
What is the Frank-Starling Mechanism?
The principle that states the more the ventricle is filled with blood (increased EDV), the more forcefully it contracts.
142
What are positive inotropic effects?
Factors that increase the contractility of myocytes, leading to increased stroke volume.
143
What are negative inotropic effects?
Factors that decrease the contractility of myocytes, leading to decreased stroke volume.
144
Define the term ejection fraction
The percentage of blood pumped out of the left ventricle with each contraction.
145
How is ejection fraction calculated?
Ejection Fraction = Stroke Volume / End Diastolic Volume.
146
What is microcirculation?
The flow of blood within the smallest blood vessels, including capillaries and associated lymphatic vessels.
147
What is the primary goal of microcirculation?
To facilitate the exchange of nutrients and waste between blood and surrounding tissues.
148
Identify the four mechanisms of movement through capillaries
1. Diffusion
2. Transcytosis
3. Filtration
4. Reabsorption
149
How do lipid soluble molecules pass through capillaries?
By diffusing through the endothelial cells down their concentration gradient.
150
How do water soluble molecules pass through capillaries?
By passing through intercellular clefts or fenestrations down their concentration gradient.
151
Define hydrostatic pressure in microcirculation
The physical force exerted by blood upon the capillary wall.
152
What is osmotic pressure in microcirculation?
The pressure exerted by solutes in solution that draws water into the capillary.
153
What is net filtration pressure?
The difference between hydrostatic pressure and osmotic pressure that determines the movement of water.
154
Define edema
The accumulation of excess fluid in the interstitial spaces.
155
What are the four main causes of edema?
1. Increased hydrostatic pressure
2. Decreased osmotic pressure
3. Increased vascular permeability
4. Lymphatic obstruction
156
What is the lymphatic system?
A network of vessels, tissues, and organs that support immune cells and function
157
What are the main organs/tissues of the lymphatic system?
* Lymph Nodes
* Spleen
* Tonsils
* Thymus
* Red bone marrow
158
What are the three main functions of the lymphatic system?
* Fluid Recovery
* Immunity Support
* Lipid Absorption
159
How does fluid recovery occur in the lymphatic system?
Fluid absorbed into the lymphatic system (lymph) is filtered within lymph nodes and then returned to the circulatory system
160
Where is the lymphatic system located within the body?
Concentrated in the neck, axilla, chest, abdomen, and groin
161
What are lymphatic vessels?
Vessels that penetrate nearly every tissue of the body, except for cartilage, bone tissue, bone marrow, and the eye
162
What is lymph?
Fluid inside a lymphatic vessel
163
What is the role of lymph nodes in the lymphatic system?
They filter lymphatic fluid and serve as a space for immune cells to assess antigens and foreign products
164
What is lymphadenopathy?
A condition related to the enlargement of lymph nodes
165
What happens to filtered lymphatic fluid?
It is eventually dumped back into the venous system, specifically the subclavian vein
166
What are the two main ducts of the lymphatic system?
* Thoracic Duct (left side)
* Right Lymphatic Duct (right side)
167
What is edema?
The accumulation of excess fluid within tissues
168
What causes edema?
More fluid is filtered out of the capillaries than is reabsorbed back into the capillaries or lymphatics
169
What are the four main causes of edema?
* Increased hydrostatic pressure
* Reduced osmotic pressure
* Lymphatic obstruction
* Increased vascular permeability (inflammation)
170
Fill in the blank: The lymphatic vessels are like sponges, soaking up _______.
fluid
171
True or False: Lymphatic vessels have valves that allow fluids to enter easily.
True
172
What percentage of fluid lost due to hydrostatic pressure is reabsorbed?
85%
173
What percentage of fluid is not reabsorbed and may contribute to edema?
15%
174
What is the daily amount of fluid that may remain in the interstitial space?
2-4 liters
