Cardiovascular Flashcards
1
Q
Circulation
A
Pressure-driven bulk flow of body fluids through a system of tubular vessels to all pats of the body
2
Q
Circulatory system
A
The system of vessels or other blood passages along with the blood
3
Q
How does the convective transport goes by?
A
By bulk flow
4
Q
What are some things that are carried around the body by blood or hemolymph?
A
O2, CO2, nutrients, organic wastes, hormones, immune system components, heat, platelets, RBCs
5
Q
What are the three components in the cardiovascular system?
A
- Pumps (heart)
- Tubing (blood vessels)
- Fluid
6
Q
How would you expect the blood to flow from one point to other?
A
By pressure gradient, more pressure in the point that it starts to flow
7
Q
How is rate measured?
A
As a unit of time
8
Q
Volumetric flow or volumetric flow rate?
A
Volume passing through as cross-sectional area over time. Expressed as m2/s or L/min
9
Q
What is Q?
A
Volumetric flow or volumetric flow rate
10
Q
Which one is the formula of volumetric flow?
A
Q = A x V
11
Q
What is A in the formula of volumetric flow?
A
A = cross- sectional area through which the fluid flows (m2)
12
Q
What is V in the formula of volumetric flow?
A
V = velocity (m/s)
13
Q
When is Q conserved?
A
When the system is closed
14
Q
What happens when the pipe narrows?
A
The velocity increases to maintain the same flow rate
15
Q
Which factors affects the rate of flow?
A
- Pressure difference
- Vessels radius: directly proportional to the fourth power of the radius
- Vessel length: longer the vessel more friction and esistance
- Viscosity of the fluid: higher viscosity, more resistance
- Elasticity and compliance: elasticity of the artery allows smooth flow
16
Q
What happens in the vessels with diseases and aging?
A
The vessels increase resistance and reduce flow
17
Q
How many chambers does the heart has?
A
4 chambers
18
Q
Cardiac output
A
Amount of blood pushed out of the heart
19
Q
Stroke volume
A
Volume of blood pumped per heart cycle
20
Q
How do we calculate cardiac output (mL/min)
A
Heart rate (BPM) x stroke volume (mL/beat)
21
Q
If i have a fish in a tank, how can I make the water anoxic (without oxygen)?
A
To decrease the oxygen in the water
22
Q
Where does the blood from the left ventricle travel?
A
Travels via the aorta to the organs of the body, whereas blood from the right ventricle travels via the pulmonary artery to the lungs
23
Q
Which characteristics does the left side of the heart has?
A
- It supplies the systemic circuit
- Develops greater pressures than the right side of the heart
24
Q
What does the right side supplies?
A
It supplies to the pulmonary circuit
25
Characteristics of the pulmonary circuit?
Low resistance because of the large number of capillaries arranged in parallel and the relatively short distance traveled
26
Types of myocardium
1. Compact myocardium with coronary arteries and veins
2. Spongy myocardium with little or no development of coronary vessels
3. Myocardium composed of outer compact tissue and inner spongy tissue
27
Compact myocardium
Cardiomyocytes are densely arranged. Mammals have compact myocardium generating high pressure and maintaining rapid strong contractions
28
Spongy myocardium
Trabecular network allowing luminal blood flow. It's a rich capillary network, animals with lower metabolic demand has it and there is a low pressure for the circulatory systems
29
Which is greater the distance between heart and lung or heart and leg?
Between your heart and leg, we need more pressure
30
Why is the left ventricle thicker than the right ventricle?
Because it need to have more strength due to the blood that needs to be sent to the whole body
31
How does the blood goes through the fish?
Heart> ventral aorta > gills > dorsal aorta > systemic circulation > great veins > heart
32
What are the two potential problems in fish circulation?
- Heart is not located between breathing organ and systemic circulation, so enough pressue need to be generated to perfuse the branchial and systemic vasculature
- Oxygenation of myocardium is provided by luminal blood (spongy myocardium), relatively deoxygenated
33
How many chambers does the fish heart has?
2 main chambers
34
Does the fish heart has cardiac muscles?
Yes, and they contract in sequence with the ventricle
35
Shunting?
Redirecting blood to certain vessels or systems
36
How is the O2 delivery vs shunting in adult birds and mammals?
High metabolic rate and high O2 delivery, but not able to bypass
37
38
How is the O2 delivery vs shunting in lungfish, amphibians, non avian reptiles?
Flexibility, but low flow & low metabolic rate
39
Which ones are the cardiac pacemaker cells?
P-cells
40
Where are the P-cells located?
In the sinoatrial node (SAN) of the heart
41
Which intrinsic ability does the myogenic pacemaker has?
Spontaneously depolarize
42
Which type of impulse does myogenic pacemaker has?
Electrical impulse
43
How are connected the P-cells?
By Gap junctions
44
What does the myogenic pacemarker potential drives?
Rhythmic contractions maintaining a steady heartbeat
45
Systole
Contraction phase of a heart chamber
46
Diastole
Relaxation phase of a heart chamber
47
What is the first step of the heart contraction cycle?
Ventricular diastole, pressure in the atria exceeds ventricular pressure. The AV valves open and the ventricles fill passively
48
What is the second step of the heart contraction cycle?
Atrial systole, atrial contraction forces additional blood into ventricles
49
What is the third step of the heart contraction cycle?
Ventricular systole, (isovolumetric contraction), ventricular contraction plushes the AV valves closed and increases pressure inside the ventricle
50
What is the fourth step of the heart contraction cycle?
Ventricular systole (ventricular ejection), increased ventricular pressure forces the semilunar valves open and blood is ejected
51
What is the fifth step of the heart contraction cycle?
Ventricular diastole (isovolumetric relaxation), as the ventricles relax, pressure in the arteries exceeds ventricular pressure, closing the semilunar valves.
52
There are conditions where the flaps of an AV valve don’t close properly. What do you think would happen to blood flow & volume ejected from the ventricle?
Some blood flows back into the atrium, reducing the amount ejected from the ventricle
53
During atrial fibrillation, the contraction of the atria becomes disorganized. Why do you think this isn't necessarily fatal (though it is serious)?
The ventricles can still fill passively and pump blood, so circulation continues — but less efficiently. It’s serious, but not usually fatal on its own
54
Which two nodes do the heart has?
SA and AV node.
55
P wave?
Atrial contraction, depolarization
56
QRS complex
Ventricular contraction, depolarization
57
T-wave
Recovery of the venricles, repolarization
58
Why does ECG don't look like an action potential?
Because it's a recording from body surface
59
What does the ECG amplitude depends on?
- Tissue mass
- Signal's rate of change
60
What does ECG sign (+/-) depends on?
- Direction signal is traveling
- If you're measuring depolarization or repolarization
61
In what is cardiovascular egulation based on?
Mean arterial pressure (MAP)
62
MAP
Average pressure in arteries over a heartbeat cycle
63
How is the MAP sensed?
With aortic & carotid baroreceptors
64
What does baroreflexes regulate?
Pressue
65
What are the elements of MAP?
- Cardiac output (CO)
- Total peripheral resistance (TPR)
66
What is included in cardiac output?
- Heart rate (HR)
- Stroke volume (SV)
67
What is included in total peripheral resistance?
- Arteriole radius
- Blood viscosity
68
Which one is the neurotransmitter (s) in the parasympathetic way?
Ach
69
Which one is the neurotransmitter (s) in the sympathetic way?
Epinephrine & norepinephrine
70
Which one is the receptors on heart in the parasympathetic way?
Muscarinic
71
Which one is the receptors on heart in the sympathetic way?
Beta-adrenergic
72
Which one is the receptors on arterioles in the parasympathetic way?
none
73
Which one is the receptors on arterioles in the sympathetic way?
Alpha-adrenergic
74
Intercalated disks
Gap junctions and localized mechanical adhesions
75
Accessory/auxiliary hearts
Secondary/local hearts that assist with the pumping of blood through localized parts of the body
76
Myocardium
Muscle tissue of a heart
77
Isovolumetric contraction/isometric contraction
Period where ventricular pressure is greater than atrium (atrio-ventricular valves close) but lower than aorta (aortic valve not pushed open) = volume in ventricle is constant
78
Ventricular ejection
Marked by opening of aortic valve and ends when it closes
79
Isovolumetric relaxation
Ventricular pressure falls with both inflow/outflow valves closed
80
Ventricular filling
Ventricular pressure below atrial pressure, inflow valve opens
81
Cardiac output
Volume of blood pumped per unit time, cardiac output = heart rate * stroke volume
82
In mammals/birds, ventricular myocardium is compact :
Muscle cells are close together and blood cannot flow from ventricular lumen among myocardial cells
83
Coronary artery
Branch from systemic aorta that carries oxygenated blood to capillary beds throughout the myocardium
84
Coronary veins
Carries blood from myocardium into the right atrium
85
Pacemarker
Cell or set of cells that spontaneously initiates the rhythm of depolarization of the heart
86
Myogenic
Electrical impulse to contract originates in muscle cells
87
Neurogenic
Each impulse to contract originates in neurons
88
Conduction
The process by which depolarization spreads through vertebrate/myogenic hearts
89
P wave
Depolarization of myocardium of the 2 atria
90
QRS complex
Depolarization of myocardium of the 2 ventricles (ventricular contraction)
91
T wave
Repolarization of the ventricles
92
Regulatory neurons
CNS neurons that modulate heart action
93
Intrinsic controls
Occur without the mediation of hormones or extrinsic neurons
94
Frank-Starling mechanism
Intrinsic control, stretching of cardiac muscle leads to increased force of contraction
95
Perfusion
The forced flow of blood through blood vessels
96
Blood pressure
Produced by the heart and is the principal factor that causes blood to flow through the vascular system, amount of pressure by which the blood exceeds the ambient pressure
97
Systolic pressure
The highest pressure attained at the time of cardiac contraction
98
Diastolic pressure
The lowest pressure reached during cardiac relaxation
99
Fluid-column effects
In an unobstructed vertical column, fluid exerts increasing pressure as height is increased
100
Open circulatory system
Blood leaves discrete vessels and bathes at least some nonvascular tissues directly
- Hemocoel: open space where fluid is "dumped"
- Hemolymph: fluid that comes into direct contact with cells, cannot differentiate as blood in vs. out of vessel because it occupies both of these spaces
101
Closed circulatory system
Always a barrier separating blood from other tissues
102
Vascular endothelium
Single-layered epithelium lining all blood vessels
103
Arteries
Thick walls lined with muscle and elastic tissue
104
Pressure-damping effects
Effect of arterial elasticity - reduces variations in arterial pressure over the cardiac cycle
105
Pressure-reservoir effects
Effect of arterial elasticity - maintains pressure in arteries even when heart is at rest between beats
106
Microcirculatory beds
Consist of arterioles, capillaries, capillary beds, venules
107
Arterioles
Walls have smooth muscle and connective tissue, smooth muscle is involved in vasomotor control of blood distribution (changes luminal radius of blood vessel to direct blood flow)
108
Capillaries
Walls consist of vascular endothelium, usually fenestrated (physical gaps in the wall), the primary site of oxygen, water, and exchange of other materials between blood and tissues
109
Capillary bed
Consist of many capillaries that branch and anastomose among the cells of a tissue, walls contain aquaporins which facilitates osmosis between blood and tissue fluid outside capillaries
110
Angiogenesis
The process of forming new capillaries and other microcirculatory elements
111
Venules
Small vessels with thin walls containing muscle and connective tissue
112
Veins
Blood is low pressure, contains passive one-way valves, capacitive properties allows holding of blood that cannot be housed elsewhere in the circulatory system
113
Ultrafiltration
Pressure-driven bulk flow of fluid out of the blood plasma across the capillary walls
114
Colloid osmotic pressure
Difference in osmotic pressure of blood plasma to extracellular tissue fluid (plasma has more dissolved proteins)
115
Starling-Landis hypothesis
Overall effect is a net loss of fluid to interstitial fluid, which is picked up to the lymphatic system
116
Pulmonary circuit
Blood leaving heart to go to lung
117
Branchial circuit
In water breathers, heart to gills
118
Systemic circuit/circulation
Blood to body tissues
119
Lobster heart (open cardiovascular system)
Heart contraction squeezes hemolymph which eventually spills into hemocoel
Ostium = pore/opening on heart where hemolymph re-enters, has valves that prevent hemolymph from leaving during contraction
Spring-like ligaments/suspensory ligaments connects heart to structures around it, stretched during contraction
120
Fish heart
- 2 Chamber heart: 1 atrium and 1 ventricle
- Sinus venosus: collects blood, pacemaker of heart beat
- Atrium: muscular, contracts, job is to fill the ventricles, primer pump
- Ventricle: muscular, contracts, power pump
- Bulbus arteriosis (teleosts) or conus arteriosus (elasmobranchs, lungfish, bowfin)
- Aorta
121
Bulbus arteriosis (in teleosts)
Valves keep blood moving toward the aorta
122
Conus arteriosis (in elasmobranchs, lungfish, bowfin)
Muscular, contractile ability, also helps depulsate and decrease pressure of ventricle's blood surge
123
Circulatory plan of water breathers
- Heart, O2 source, and tissues in series with each other, low pressure blood going into system circuit limits metabolism (limits rate of blood being pushed through circulation)
- Heart is also perfused with low O2 blood, limits heart's ability to pump blood
124
Circulatory plan of air and water breathing fish (fish with ABO - air breathing organs)
- Heart, O2 source, and tissues in parallel with each other
- Heart receives low O2 venous blood mixing with high O2 blood from O2 source (heart gets more O2 than water breathers)
125
Shunting
The ability of blood to follow pulmonary/branchial circuit or systemic circuit
126
Pulmonary vasomotor segment in lungfish heart
Band of muscle that surrounds ductus (leading to aorta/system circuit) and pulmonary artery. contraction controls shunting, when breathing air, pulmonary artery opens and ductus closes
127
When amphibians hold breath:
Blood is shunted to systemic circuit via pulmonary-to-systemic shunt (constriction of pulmonary blood vessels, higher resistance=less blood flow in pulmonary circuit)
128
Right ventricle of crocodilian heart leads to:
Pulmonary artery and left aorta (systemic arch)
129
Left ventricle of crocodilian heart leads to:
Right aorta (systemic arch)
130
Foramen of Panizza
Hole between L & R aorta, outside of heart, allows mixing between blood
131
Cogwheel valves (in crocodilian heart)
2 Swellings near pulmonary artery in right ventricles, active valves, contracts when breath holding and closes pulmonary artery, this generates high pressure in right ventricle which pushes blood out at high pressure to left aorta (shunts low O2 blood into systemic circuit)
132
Pulmonary valve + Aortic valve
- Semilunar valves
- Tricuspid
133
Atrioventricular (AV) valves
Prevents backflow from ventricles to atria
- Right AV = tricuspid
- Left AV = bicuspid/mitral valve
134
Cordae tendinae
Connected to mitral/bicuspid valve on left side of heart, prevents prolapsed valve, attached to papillary muscle on ventricular valves
135
Fetal pulmonary to aortic shunt
Right atrium to right ventricle to ductus arteriosus to aorta
136
Foramen ovale
- Valve in fetal heart
- Provides a passage between right and left atrium, so that blood can pass to left ventricle and then aorta (another shunt passage to systemic circuit)
137
Fetal circulatory system changes after taking first breath:
- Pulmonary pressure falls (stops all shunting passages)
- Left pressure > right pressure (can't be pushed through foramen ovale, closes and becomes nonfunctional)
- Pulmonary artery blood flows to the lungs instead of the aorta (lower pressure in lungs)
- Smooth muscle in ductus arteriosus squeezes closed and forms ligamentum arteriosis
138
Dihydropyridine receptors
Voltage gated calcium channels on T-tubules of cardiac muscle, not linked to ryanodine receptors on sarcoplasmic reticulum (entry of calcium binds to ryanodine receptors and causes release of intracellular calcium stores = calcium-induced calcium release)
139
Cardiac glycosides
- Modifies internal calcium levels. Ex. digitalis (foxglove), oubain, digoxin blocks Na-K pump
- Increased intracellular Na causes Na/Ca pump to increase such that intracellular Ca rises and can bind to ryanodine receptors (causes increased heart rate and force of contraction)
140
What are 2 kinds of cardiac muscle?
1) Working myocardium (lots of myofibrils, lots of SR, prolonged action potential)
2) Pacemakers (depolarize spontaneously, conducting action potentials, don't contract)
141
What are the 4 types of pacemaker cells?
1) Sinoatrial node (SA) node (right atrium)
2) Atrioventricular node (AV)
3) Bundles of HIS
4) Purkinje fibres
142
AV nodal delay
AV nodal link between atria and ventricles is very high resistance, requires more time for membrane depolarization to reach threshold.
This causes atrial contraction to occur before AV node initiates ventricular contraction
143
Amplitude of electrocardiogram signal that reaches body surface is influenced by:
- Mass of muscle
- Rate of depolarization
144
Einthoven's Triangle
Leads placed on left arm, right arm (reference=0), left leg (sense)
145
PR segment
2 electrodes are seeing the same signal, caused by AV nodal delay
146
ST segment
Plateau of ventricular action potential
147
TP segment
Diastole (ventricular relaxation)
148
Chronotropic
Effect on heart rate
149
Inotropic
Effect on strength of contraction
150
Lusitropic
Effect on relaxation
151
Dromotropic
Effect on rate of spread of cardiac action potential
152
Parasympathetic control of heart rate
- Cholinergic (ACh) neurons
- Main = vagus nerve, mostly affects pacemakers
- Increases K+ conductance (slower rate of rise of pacemaker potential)
- Slows heart rate, rate of depolarization, increases AV nodal delay
153
Sympathetic control of heart rate
- Adrenergic (NE) neurons
- Activated by catecholamines
- Acts on pacemakers and working muscle
- Decreases K+ conductance
- Easer for pacemaker potential to rise, increased heart rate, increased spread of depolarization, decreased - AV nodal delay
- Catecholamines binding to B1 receptors on working muscle activates protein kinases that phosphorylate Ca channels and troponin, causes increased Ca entry and increased binding of Ca to troponin, increased force of contraction (inotropic effect)
154
Stroke volume
Blood ejected per beat (mL/beat)
155
Heart rate
Contractions/min
156
Cardiac output
Heart rate * Stroke volume = mL/min
157
Frank/Starling Relationship or Law of the heart
Higher end-diastolic volume is proportional to stroke volume, until end-diastolic volume reaches a very high volume and causes congestive heart failure
158
Sympathetic stimulation increases heart contraction force, what effects does this have on a SV vs. EDV figure?
Causes an upward shift, potential treatment for congestive heart failure
159
What affects end-diastolic volume?
- EDV is a function of how much blood is returned to the heart (venous return) and is affected by:
- Squeezing veins (sympathetic stimulation of smooth muscle around the veins)
- Skeletal muscle contraction helps with venous return
- Respiratory pumping (inspiration decreases intra-thoracic pressure and right atrium pressure and increases venous return)
- Cardiac suction (elastic recoil of the heart)
- Valves in veins (passive structures that help return blood to the heart)
