Cardiac Output - Blood Pressure Flashcards
Review for Test II of Physiology Class - Second Semester
1
Q
Include all the activities associated with blood flow through the heart during one complete beat of the heart.
A
Cardiac Cycle
2
Q
4 Periods of Cardiac Cycle
A
atrial systole→ atrial diastole → ventricular systole → ventricular diastole
3
Q
Total duration of the Cardiac cycle
A
0.8 seconds
4
Q
also called diastole.
- The ventricles expand
- Pressure drops below atrial pressure
- AV valve open
- Blood flowing down to the ventricle
- Right atrium contracts slightly before left atrium (since it received the AP first)
- As the ventricles fill the valve cusp float upwards
- At the end of filling the ventricles have the end-diastolic volume (EDV) about 130 mL.
A
Ventricular Filling
5
Q
End-Diastolic Volume (EDV) = ___ mL
A
130 mL
6
Q
a. Atria repolarise and remain in diastole for the rest of the cycle
b. Ventricular depolarization occur, QRS complex occur, and ventricle begin contraction.
c. AV valves close - First Heart Sound occurs
d. Blood rushes to the SLvalve cusps
e. Ventricle contract but the blood has not left it yet, hence ________. Pressure in aorta is about 80 mm Hg and pulmonary trunk about 10 mm Hg.
A
Isovolumetric contraction
7
Q
Pressure in Aorta(a) and Pulmonary Trunk(b) in Isovolumetric Contraction.
A
a. 80 mm Hg
b. 10 mm Hg
8
Q
a. Ventricular pressure exceeds aortic pressure and pulmonary arterial pressure and forces SL valves upward and open.
b. Peak pressure in aorta about 120 mmHg and peak pressure in the pulmonary trunk about 25 mm Hg
c. T wave appears at the peak of ventricular pressure
d. Ventricle forced out just 54% of its volume (i.e., 70mL of the 130 mL) it contained at the EDV. The amount force out of the ventricles is called the stroke volume
Stroke Volume (SV) = 70 ml
e. The ventricle still has 130-70 = 60 mL left in it after contraction (systole)
The amount left in it is called the end-systolic volume (ESV)
End-systolic volume (ESV) = 60 mL
This is of clinical importance in heart failure.
A
Ventricular Ejection
9
Q
Peak pressure in Aorta(a) about _____ mmHg and peak pressure in the Pulmonary Trunk(b) about _____ mm Hg
A
a. 120 mm Hg
b. 25 mm Hg
10
Q
The amount force out of the ventricles is called the _________.
A
Stroke volume
11
Q
Ventricle forced out just ___% of its volume.
i.e., 70mL of the 130 mL
A
54%
12
Q
Stroke Volume (SV) = ___ ml
A
70 mL
13
Q
The ventricle still has __ mL left in it after contraction (systole).
A
60 mL
14
Q
The amount left in the ventricle after contraction is called the ___________. This is of clinical importance in heart failure.
A
end-systolic volume (ESV)
15
Q
End-systolic volume (ESV) = ___ mL
A
60 mL
16
Q
a. Early diastole and T wave ends and ventricles expand
b. Pressure falls in the ventricle and blood falls backward onto the SL valves
c. Back flow of blood fills the cusps and causes the valves to close
d. Close of the SL valves produces the second heart sound!
e. AV valves not yet open and the SL valves are closed, hence isovolumetric relaxation.
A
Isovolumetric Relaxation
17
Q
AV valves not yet open and the SL valves are closed, hence ____________.
A
Isovolumetric Relaxation
18
Q
What causes the SL valves to close?
A
Back flow of blood fills the cusps
19
Q
a. AV valve opens, filling begins again.
b. A third sound may be heard due to expansion of the empty ventricle and the beginning of filling.
c. Blood run directly from the atria into the ventricles
d. Notice that by the time the atria contracts, 75% of the blood that entered in them have already passed into the ventricles. So atria contraction contributes just 25% more blood to the ventricles.
A
After Isovolumetric Relaxation
20
Q
Why would a third sound may be heard?
A
Due to expansion of the empty ventricle and the beginning of filling.
21
Q
Notice that by the time the atria contracts, ___% of the blood that entered in them have already passed into the ventricles. So atria contraction contributes just ____% more blood to the ventricles.
A
a. 75%
b. 25%
22
Q
Formula for EDV
A
EDV = SV + ESV
23
Q
The volume of blood ejected by each ventricle in one minute.
A
Cardiac Output (CO)
24
Q
Formula for Cardiac Output (CO)
A
CO = Heart Rate x Stroke Volume
25
Normal CO (L/min)
Normal CO = 75 bpm x 70 ml/ beat =5.25L/min
26
During exercise cardiac output may be as high as ____L/min in normal exercise.
21 L/min
27
The amount of blood pumped out in one cardiac cycle (about 70 mL)
Stroke volume
28
Stroke Volume depends on: (3)
1. Preload
2. Contractility
3. After load
29
The amount of tension in the ventricular myocardium before it contracts. The more blood the ventricle receive the more force they contract (within limit). It can be considered as the degree of stretch at the ventricle
Preload
30
Refers to how the ventricles contract for a given preload.
Contractility
31
Contractility depends on ___++ and ___++
Na++ and Ca++
32
________ produces strong and prolonged contraction.
Hypercalcaemia
33
________ leads to weak irregular heartbeat. Hence affecting Stroke volume
Hypocalcaemia
34
Refers to the pressure in the arteries just outside the semilunar valves.
After load
35
Increase Afterload lead to decrease ______.
stroke volume
36
As____ work harder to overcome afterload, they enlarge and the affected arteries become weaker.
Ventricles
37
Factors Affecting Cardiac Output
1. Crisis stressors
2. Low blood pressure
3. High blood pressure
4. Exercise
5. Decreased blood volume
38
Heart sounds occur when _______.
heart valves close
39
Basis rhythm is _______, and so on.
lup-dup pause lup-dup
40
First sound occurs when _____. it signifies the beginning of ventricular systole
AV vales close
41
• _____ sound is louder and longer and with more resonance that the ____ sound
First; second
42
Second sound occur when the _____.
semi-lunar valves close
43
Abnormal heart sounds.
Heart murmurs
44
The ______closes slightly before the _____ valve.
The bicuspid valve (left) closes slightly before the tricuspid (right) valve.
45
The ____ SL valve closes slightly before the ____ SL valve.
The aortic SL valve closes slightly before the pulmonary SL valve.
46
The force the blood exerts along the wall of blood vessel.
Blood pressure (BP)
47
Formula for BP
Pressure = Force/area (mm Hg)
48
BP can be measured in the heart or blood vessels by inserting a catheter or needle connected to a manometer.
Cardiac catheterisation
49
Routine clinical investigation involve measuring BP in systemic artery with the aid of a ______.
sphygmomanometer
50
The BP in the _____ Artery represents the maximum arterial BP found anywhere in the body. (Note it proximity to the heart)
Brachial
51
Two kinds of pressure that are usually used clinically
1. Systolic BP
| 2. Diastolic BP
52
peak arterial BP during ventricular contraction.
Systolic BP
53
Normal systolic BP
120 mm Hg
54
minimum arterial BP occurring during ventricular relaxation (between heart beats)
Diastolic BP
55
Normal Diastolic BP
typically 80 mm Hg (Normal = 75 mm Hg)
56
Blood flow throughout circulatory system is dependent on (2).
1. the pumping action of the heart and
| 2. the pressure gradient (i.e., the blood flow from areas of high pressure to areas of low pressure).
57
Systemic blood pressure is highest in the ___ and low in the _____, reaching 0 mm Hg. in the right atrium.
Systemic blood pressure is highest in the aorta and low in the vena cavae, reaching 0 mm Hg. in the right atrium.
58
As the heart pumps blood into the aorta, the volume and force of the blood cause the aorta to stretch and the blood pressure climbs to the _________ seen in the circulatory system.
maximum (peak) pressure
59
The normal peak pressures (~120 mm Hg), is usually called the __________.
systolic blood pressure, SBP
60
Because the pressure in the _____ portion of the aorta is lower than the peak pressure, the blood moves forward in the vessel (i.e., down the pressure gradient).
distal
61
When the left ventricle relaxes, the _____ valve prevents the return of the blood to the ventricle from the aorta, and the walls of the aorta recoils, thus maintaining high blood pressure to keep the blood flowing forward.
aortic semi-lunar valve
62
The aorta blood pressure eventually falls to about ______ mm Hg in healthy individual while the ventricle is resting.
70-80 mm Hg
63
The aortic pressure (70-80 mm Hg) is known as the ___________.
diastolic blood pressure, DBP
64
The difference in pressure between the systolic pressure (SDP) and the diastolic pressure (DBP) is called the ________ .
pulse pressure
65
This can be felt as a throbbing pulsation in time (i.e. pulse rate) in the artery during systole as the arteries expand under the force of the blood being pumped from the ventricle.
Pulse pressure
66
Formula for pulse pressure
Pulse Pressure = Systolic BP – Diastolic BP
67
Pulse pressure can vary with (2).
hormones and chronic disease conditions.
68
Since arterial blood pressure is not constant throughout the circulatory system, the average or ___________ is considered a more clinically useful measure of blood pressure in the arteries than arterial pressure at a single point in an artery.
mean arterial pressure (MAP)
69
Formula for mean arterial pressure (MAP)
Mean Arterial Pressure (MAP) = diastolic pressure + 1/3(pulse pressure)
70
This equation is useful in determining the volume of blood put out by the heart per minute (i.e., the cardiac output) if the peripheral resistance in the vessels is known.
CO = MAP/R
| - The cardiac output (CO) equals the mean arterial pressure divided by the peripheral resistance (R)
71
In the large diameter blood vessels (aorta and arteries) the blood pressure is _____ and the peripheral resistance is ___.
High; low
72
The major function of the arterioles.
To lower the BP presented to capillary beds.
73
But as the blood travels through the smaller diameter vessels –arterioles and capillaries - the peripheral resistance _____ and the blood pressure _____ progressively.
increases; decreases
74
_____ pressure is usual steady and changes only minimally.
Venous pressure.
75
When a vein is cut, one can notice that the blood flows _____ rather than spurts as would be the case when an ______ is cut.
steadily; artery
76
Venous pressure falls eventually to ____mm Hg. This is the result of the high peripheral resistance encountered by the blood as it flows through muscular arterial vessels.
0 mm Hg
77
Three mechanisms move blood back to the heart:
1. Respiratory pump
2. Skeletal Muscle Pump
3. Smooth Muscle around veins.
78
Pressure changes in the ventral cavity during breathing created a ______ that helps to pull blood to the heart.
Respiratory pump
79
Skeletal muscle active acts as a ______ pump.
Muscular pump
80
___________ constrict under sympathetic command and force blood to the heart.
Layers of smooth muscle around veins
81
The presence of _____ in the extremities prevents blood from flowing backwards.
valves
82
I a tissue is not receiving adequate blood supply it becomes hypoxic and substances such as CO2, K+, H+, lactic acid, and adenosine accumulate. These substances stimulate vasodilation which increases perfusion of the tissue. The vessels will then constrict when the O2 reach normal.
Auto regulation
83
When a tissue doesnt get enough blood, it becomes _____.
Hypoxic
84
Chemical secreted by platelets, endothelial cells and certain vascular tissue stimulate ______
Vasodilation
85
Bradykinin, histamine and prostaglandin stimulate ________
Vasodilation
86
Vasomotor area of the ______ through the SNS regulates BP.
Medulla Oblongata
87
Chemical receptors (chemoreceptors) in the ______________ monitor O2, which, in turn influence BP.
Aortic arch and large arteries
88
Hormones such as ___(5)____ help to regulate BP.
renin, atrial natriuretic peptide, ADH, Catecholamine, and angiotensin ll
89
BP is monitored by ____ (in carotid and aortic arch) and _____. (Receptors)
baroreceptors; stretch receptor
90
Normal BP in Aorta
75 - 120 mm Hg
91
Normal BP in Arteries
75 - 120 mm Hg
92
Normal BP in arterioles
75 - 30 mm Hg
93
Normal BP in Capillaries
30 - 15 mm Hg
94
Normal BP in Venules
5 – 18 mm Hg
95
Normal BP in Veins
0 - 5 mm Hg
96
Normal BP in Vena Cava
0 mm Hg.
97
To maintain adequate blood pressure from head to toe, the body must regulate three variables: (3)
1. Cardiac output
2. Peripheral resistance
3. Blood flow rate
98
These maintenance variables are tightly controlled in the body through _____(2), and on a short term and long term basis.
neural and hormonal controls
99
The cardiovascular centre in the medulla oblongata helps to regulate ________(2) thus determining cardiac output.
heart rate and stroke volume
100
________ controls peripheral resistance.
| Hence output from the cardiovascular centre controls blood pressure in the body.
Cardiovascular centre via vasomotor (sympathetic) nerves
101
To provide appropriate output to the body the cardiovascular must receive adequate input. The input information comes to the ______(3) from baroreceptors, chemoreceptors and other receptors in the body
cortex, limbic system and hypothalamus
102
Neural control operates through a _____ which involves baroreceptors and afferent fibres from the vasomotor centre of the medulla oblongata.
reflex arc
103
The vasomotor centre regulates changes in the _____ of the vessels which affect peripheral resistance and cardiac output.
diameter
104
Baroreceptors (blood pressure (stretch) receptors) are located in _________.
major blood vessels such as the carotid sinuses and aorta
105
Detect the blood pressure in the vessels when the walls of the vessels are stretched.
Baroreceptors
106
Stretching information from baroreceptors goes rapidly to the ______ and this centre regulates the diameter of blood vessels.
vasomotor centre
107
Based on the information received, the centre can constrict both arteries and veins, thus increased __________.
peripheral resistance
108
Since cardiac output is a function peripheral resistance, the end result is decreased _____.
cardiac output
109
Information from baroreceptors also stimulates the _____ which can inhibit the cardioacceleratory centre which will then slow the heart rate.
PaSNS
110
Centre in PaSNS that slows the heart rate.
cardioacceleratory centre
111
Peripheral resistance and _______ are regulated and they influence the blood pressure.
cardiac output
112
Chemoreceptors in the ____(2)____ also regulate blood pressure.
aortic arch and some large blood vessels
113
_____ monitor the chemical composition of the blood - acidity (H+), CO2 and O2.
Chemoreceptors
114
________ stimulate the chemoreceptors which then send impulses to the cardiovascular centre in the medulla.
Hypoxia, acidosis and hypercapnia (excess CO2)
115
The cardiovascular centre responds to the chemoreceptors by increasing ______ which, in turn, increases blood pressure
peripheral resistance
116
The chemoreceptors also send impulses to the _______ whose responses to the stimuli are to adjust respiratory rates.
respiratory centre (in the brain stem)
117
Condition in which the blood has high CO2
Hypercapnia
118
The ANS has an indirect effect on ____ blood flow.
coronary
119
____ stimulation increases heart rate and contractility →increased O2 demand
Sympathetic
120
Primary action of sympathetic nerve fibres on coronary arteries is to cause a _________
marked increase in coronary blood flow.
121
_______ stimulation slows the heart rate and depresses contractility → decreased cardiac oxygen consumption and therefore coronary blood flow decreases.
Parasympathetic
122
Hormones help to regulate ____ both the in the short term and long term;
BP
123
______ can alter cardiac output, vascular resistance or adjust total blood volume.
Hormones
124
Hormones that Influence BP by increasing heart rate and heart contractility → increased BP
Epinephrine (E) and norepinephrine (NE)
125
Hormones that increases systemic vascular resistance → increased BP
ADH and Angiotensin ll
126
Hormones that decreases systemic vascular resistance → decrease BP
Atrial natriuretic peptide(ANP), nitric oxide
127
Hormone that decreases blood volume
ANP (alone)
128
Hormones that increases fluid retention → blood volume
Aldosterone, Antidiuretic Hormone (ADH)
129
The short-term control of blood pressure, via _____(2) regulates momentary variation fluctuation in BP.
neural and hormonal control
130
The nervous system via the ANS regulates the (3) (related to short term control of BP)
i) mean arterial BP (MAP)
ii) peripheral resistance and
iii) the blood distribution to organ
131
Role of hormones in the short term control of BP
The hormones regulate blood volume, cardiac output and vascular resistance
132
Long term regulation of BP is obtained by altering (2).
MAP and peripheral resistance
133
Two major renal systems work to regulate MAP and peripheral resistance:
1. Renal output regulation of fluid volume
| 2. The Renin- Angiotensin Mechanism
134
System that changes both fluid volume and peripheral resistance.
The Renin- Angiotensin Mechanism
135
Renal system that directly affects blood pressure
Renal output regulation of fluid volume
136
The force per unit area exerted on a vessel wall by the blood contained in the vessel; it is expressed in mm Hg.
Blood pressure
137
The opposition to blood flow encountered in the peripheral (system) circulation. The resistance (R) to flow in vessels outside the heart is greater than in the heart. Most resistance is contributed by the smaller vessels – arterioles, capillary and venules.
Peripheral resistance –
138
Internal resistance in the blood that opposes blood flow; it is related to the thickness of the blood. Blood viscosity increases as the number of red blood cells (RBC) present in the blood increases, since RBCs are the largest portion of formed elements in the blood. Hence, the condition called polycythemia causes an increase in blood viscosity, Viscosity decreases in the presence of anaemia.
Blood viscosity
139
The longer the blood vessel the greater the resistance it offers to blood flow. Hence, an increase in body size leads to an increase in peripheral resistance.
Vessel Length and Resistance
140
The smaller a vessel the greater the resistance to blood flow in the vessel. As vessels diameter change the resistance to flow changes dramatically. Whereas large arteries close to the heart contribute very little to peripheral resistance; the small (diameter) arterioles (which can enlarge or constrict) are the major vessels that determine the peripheral resistance.
Blood vessel diameter
141
The volume of blood flowing through a vessel or organ measured in mL/minute.
- is directly proportional to the difference between two points in the vessel (P1 – P2) and inversely related to the peripheral resistance R, in the vessel.
Blood flow (F)
142
Note that the R plays the most important role in the equation. When a vessel constricts, (i.e., when R increases), the flow rate (F) falls. When the vessel dilates, i.e., when R decreased thus causes the flow rate (F) to increase. In other words:
Vasoconstriction leads to _____ BP in the vessel
Vasodilation leads to _____ BP in the vessel
increased; decreased
143
The volume of blood that flows from the heart per minute.
Cardiac Output (CO)
144
Formula for blood flow
F = (P1 – P2)/R
145
Hormone that is a weak vasoconstrictor, it causes the smooth muscles to constrict
Angiotensin I
146
Hormone that is a potent vasocontrictor
Angiotensin II
147
Resistance that blood encounters as it flows
Peripheral Resistance
148
Respiration that produces lactic acid
Anaerobic Respiration
149
When the CO2 levels in the blood increase, the ph of the blood..
decreases. it becomes more acidic.
150
Chemoreceptores mainly regulates 3.
CO2, PH, Hydrogen Ions
151
Sensors that picks up stretch info (pressure) up to the medulla oblangata.
Barorecceptors
152
System that dilates the coronary vessels to decrease heart rate.
SNS
153
Low volume of the blood results to ____ BP
Low BP
154
Stretched atria releases ______ that causes the kidneys not to reabsorb sodium.
Atrianaturatic Peptide
155
The pressure that the ventricles has to overcome (SL valve)
Afterload
156
SNS stimulates the kidney to release..
Renin
157
Active protein made by the liver associated with RAAS
Angiotensinogen
158
In order to create Angiotensin I, we need ____ form the liver and ____ from the kidneys
Angiotensinogen; renin
159
The Angiotensin I goes to the lung and the endothelial cells in the lung has ________ which converts Angiotensin I to Angiotensin II.
Angiotensin-Converting Enzyme (ACE)
160
Powerful vasoconstrictor. Also works in the adrenal gland. Peripheral Vessels constrict.
Angiotensin II.
161
Angiotensin II causes the adrenal gland to release _____ which causes Na+ and H2O Retention, which causes increased and restored blood volume.
Aldosterone
162
Peripheral vasoconstriction caused by Angiotensin II means the vessel diameter _____. Thus increasing and restoring BP.
Decreases
