Exam 2- Chapter 14 Flashcards
(150 cards)
1
Q
What does cardiac output mean?
A
Volume of blood pumped each minute by each ventricle
2
Q
What is the equation for cardiac output?
A
cardiac output = stroke volume X heart rate
(ml/minute) (ml/beat) (beats/min)
3
Q
What is the average heart rate?
A
70 bpm
4
Q
What is the average stroke volume?
A
70−80 ml/beat
5
Q
What is the average cardiac output?
A
5,500 ml/minute
6
Q
Regulation of Cardiac Rate: When does spontaneous depolarization occur at SA node?
A
when HCN channels open, allowing Na+ in
7
Q
Regulation of Cardiac Rate: What keeps HCN channels open? What does this do?
A
- Sympathetic norepinephrine (vagus nerve) and adrenal epinephrine
- Increase heart rate
8
Q
Regulation of Cardiac Rate: what opens K+ channels? What does this do?
A
- Ach
2. Slows heart rate
9
Q
Regulation of Cardiac Rate: What is the regulation of cardiac rate controlled by?
A
Cardiac center od the medulla oblongata
10
Q
What are the 3 variables that are responsible for regulation of stroke volume?
A
- End diastolic volume (EDV)
- Total peripheral resistance
- Contractility
11
Q
What is the End diastolic volume (EDV)? What is it sometimes called? How are stroke volume and EDV related?
A
- Volume of blood in the ventricles at the end of diastole
- Preload
- Stroke volume increases with increased EDV
12
Q
What is the Total peripheral resistance? How are stoke volume and Total peripheral resistance related?
A
- Frictional resistance in the arteries
2. Inversely related to stroke volume
13
Q
What is Contractility? How are stoke volume and contractility related?
A
- strength of ventricular contraction
2. Stroke volume increases with contractility.
14
Q
State the Frank-Starling law.
A
Increased EDV results in increased contractility and thus increased stroke volume
15
Q
Intrinsic control of contraction strength:
- What is this due to? Explain.
- What is that (^^) due to?
A
- Myocardial stretch
- Increased EDV stretches the myocardium, which increases contraction strength.
- Due to increased myosin and actin overlap and increased sensitivity to Ca2+ in cardiac muscle cells
16
Q
Sympathetic norepinephrine and adrenal epinephrine can increase contractility by doing what?
A
by making more Ca2+ available to sarcomeres.
17
Q
What is EDV controlled by?
A
Factors that affect venous return
1. Total blood volume 2. Venous pressure
18
Q
What factors affect venous return?
A
- Total blood volume
2. Venous pressure
19
Q
Veins are compliant. What does that mean?
A
stretch at a given pressure
20
Q
Veins or Arteries:
- What holds more blood?
- What maintains a higher pressure?
- What maintains a lower pressure
A
- Veins
- Arteries
- Veins
21
Q
How much of our body water is found within the cells?
A
2/3
22
Q
Of the remaining 1/3 of our bodies water found outside the cells, how much exist in interstitial spaces? and how much is in blood plasma?
A
- 80%
2. 20%
23
Q
What controls the movement of water between the interstitial spaces and the capillaries, affecting blood volume?
A
Osmotic forces
24
Q
Besides osmotic forces, what also plays a role in blood volume?
A
- Urine formation
2. Water intake (drinking)
25
Tissue/Capillary Fluid Exchange: What is net filtration pressure?
Hydrostatic pressure of the blood in the capillaries - Hydrostatic pressure of the fluid outside the capillaries
26
Tissue/Capillary Fluid Exchange: What is the net filtration pressure at the arteriole end? venule end?
1. 36 mmHg @ arteriole end
| 2. 16 mmHg @ venule end
27
Tissue/Capillary Fluid Exchange: what is colloid osmotic pressure due to?
due to proteins dissolved in fluid
28
Which has a higher colloid osmotic pressure: blood plasma or interstitial fluid? What is difference called? Give the number value. Where does the favor movement into?
1. Blood plasma
2. Oncotic pressure
3. 25 mmHg
4. Capillaries
29
Tissue/Capillary Fluid Exchange: what are starling forces?
combination of hydrostatic pressure and oncotic pressure that predicts movement of fluid across capillary membranes
30
Tissue/Capillary Fluid Exchange- Starling Forces: what is the equation of fluid movement?
(pc + πi) - (pi + πp)
| fluid out fluid in
31
(pc + πi) - (pi + πp)
fluid out fluid in
1. What does pc mean?
2. What does πi mean?
3. What does pi mean?
4. What does πp mean?
1. Hydrostatic pressure in capillary
2. Colloid osmotic pressure of interstitial fluid
3. Hydrostatic pressure of interstitial fluid
4. Colloid osmotic pressure of blood plasma
32
What specific part of the capillary membranes do starling forces predict?
predict the movement of fluid into the capillaries at the arteriole end and out of the capillaries at the venule end
33
What is an edema?
Excessive accumulations of interstitial fluids
34
What can an edema be a result of? (7 possibilities)
1. High arterial blood pressure
2. Venous obstruction
3. Leakage of plasma proteins into interstitial space
4. Myxedema (excessive production of mucin in extracellular spaces caused by hypothyroidism)
5. Decreased plasma protein concentration
6. Obstruction of lymphatic drainage – by parasites
7. Removal of lymphatic tissue
35
The formation of urine begins with what?
filtration of fluid through capillaries in the kidneys called glomeruli
36
How much filtrate in L, is moved across the glomeruli per day? How much is actually removed through urine? Where does the rest go?
1. 180 L of filtrate is moved across the glomeruli per day
2. 1.5 L is actually removed as urine
3. The rest is reabsorbed into the blood
37
What is the amount of filtrate reabsorbed into the blood controlled by and in response to what?
several hormones in response to the body’s needs
38
Antidiuretic hormone (ADH):
1. What is it produced by?
2. When is it released?
3. What does it stimulate?
1. Hypothalamus
2. When osmoreceptors in the hypothalamus detect increased plasma osmolarity
3. ADH stimulates water reabsorption
39
Plasma osmolarity can increase due to what?
excessive salt intake or dehydration
40
Increased plasma osmolarity also increases what?
Thirst
41
Aldosterone:
1. What is it secreted by?
2. When is it secreted?
3. What does stimulate?
4. What system is it regulated by?
1. Adrenal cortex indirectly
2. When blood volume and pressure are reduced
3. Stimulates reabsorption of salt in kidneys
4. Regulated by renin-angiotensin-aldosterone system
42
Renin-angiotensin-aldosterone system:
| What happens when blood pressure is low?
When blood pressure is low, cells in the kidneys (juxtaglomerular apparatus) secrete the enzyme renin
43
Renin-angiotensin-aldosterone system:
| After the secretion of the enzyme renin what two things happen?
1. Angiotensinogen is converted to angiotensin I
| 2. Angiotensin I is converted to angiotensin II by ACE enzyme.
44
Angiotensin II has many effects that result in what?
a raise in blood pressure
45
What are the 3 effects angiotensin II has that result in a raise in blood pressure?
1. Vasoconstriction of small arteries and arterioles
2. Stimulates thirst center in hypothalamus
3. Stimulates production of aldosterone in adrenal cortex
46
What is atrial natriuretic peptide produced by? when is it produced?
1. Atria of the heart
| 2. When stretch is detected
47
What does atrial natriuretic peptide promote? What does it inhibit?
1. Promotes salt and water excretion in urine in response to increased blood volume
2. Inhibits ADH secretion
48
Is cardiac output distributed equally or unequally to organs? Why?
Cardiac output is distributed unequally to different organs due to unequal resistance to blood flow through the organs
49
Physical laws regulating blood flow:
1. How does blood flow?
2. What is the rate of blood flow proportional to?
3. What is the rate of blood flow inversely proportional to?
1. Blood flows from a region of higher pressure to a region of lower pressure.
2. The rate of blood flow is proportional to the differences in pressure
3. The rate of blood flow is also inversely proportional to the frictional resistance to blood flow within the vessels
50
The rate of blood flow is inversely proportional to the frictional resistance to blood flow within the vessels. What is an equation for this?
blood flow = ΔP/resistance
51
In the equation: blood flow = ΔP/resistance,
| How is resistance measured?
resistance = Lη/ r4
52
In the equation: blood flow = ΔP/resistance, what is ΔP?
ΔP= pressure difference between the two ends of the tube
53
In the resistant equation: resistance = Lη/ r4:
1. What is L?
2. What is η?
3. What is r?
1. Length of the vessel
2. Viscosity of the blood
3. Radius of the blood vessel
54
Regarding the physical laws regulating blood flow: what does poiseuille's law add?
Poiseuille’s Law adds in physical constraints
55
What is Poiseuille’s Law?
blood flow = ΔPr4(π)/ ηL(8)
56
How does Vessel length (L) and blood viscosity (η) vary?
Not normally
57
What are the most important factors in blood flow? Why?
1. Mean arterial pressure and vessel radius (r)
| 2. Because Vessel length (L) and blood viscosity (η) do not vary normally
58
What provides the greatest resistance to blood flow and can redirect flow to/from particular organs?
Vasoconstriction of arterioles
59
What is Total Peripheral Resistance?
The sum of all vascular resistance in systemic circulation
60
Total Peripheral Resistance:
1. Blood flow to organs runs parallel to each other, so a change in resistance within one organ _________.
2. Vasodilation in a large organ may _____ total peripheral resistance and mean arterial pressure.
3. ________ and _______ elsewhere make up for this.
1. Blood flow to organs runs parallel to each other, so a change in resistance within one organ does not affect another.
2. Vasodilation in a large organ may decrease total peripheral resistance and mean arterial pressure.
3. Increased cardiac output and vasoconstriction elsewhere make up for this.
61
Extrinsic Regulation of Blood Flow:
| What two factors are considered extrinsic regulators of blood flow?
Autonomic and endocrine control of blood flow
62
Extrinsic Regulation of Blood Flow:
| What are 5 specific structures/hormones that extrinsically regulate blood flow?
1. Sympathetic nerves
2. Parasympathetic nerves
3. Paracrine control
4. Bradykinin/Nitric Oxide/Prostaglandin I2 (to produce vasodilation in smooth muscle)
5. Endothelin-1
63
What are two ways sympathetic nerves extrinsically regulate blood flow?
1. Increases total peripheral resistance through release of norepinephrine onto smooth muscles of arterioles in the viscera and skin to stimulate vasoconstriction
2. Acetylcholine is released onto skeletal muscles, resulting in increased vasodilation to these tissues (due in part to adrenal epinephrine)
64
How do parasympathetic nerves extrinsically regulate blood flow? What is this limited to? Why is this less important in controlling total peripheral resistance?
1. Acetylcholine stimulates vasodilation
2. Limited to digestive tract, external genitalia, and salivary glands
3. Less important in controlling total peripheral resistance due to limited influence
65
What is paracrine control? (extrinsic regulation of blood flow)
Molecules produced by one tissue control another tissue within the same organ.
66
What is an example of paracrine control in the extrinsic regulation of blood flow?
The tunica intima produces signals to influence smooth muscle activity in the tunica media.
67
Extrinsic Regulation of Blood Flow:
| What is smooth muscle relaxation influenced by? How?
1. bradykinin, nitric oxide, and prostaglandin I2
| 2. to produce vasodilation
68
Extrinsic Regulation of Blood Flow:
| What does Endothelin-1 do?
stimulates smooth muscle contraction to produce vasoconstriction and raise total peripheral resistance
69
What is another name for Intrinsic Regulation of Blood Flow?
autoregulation
70
What organs use Intrinsic Regulation of Blood Flow/auto-regulation? Why?
1. Used by some organs (brain and kidneys)
| 2. To promote constant blood flow when there is fluctuation of blood pressure
71
Intrinsic Regulation of Blood Flow:
| What are myogenic control mechanisms?
Vascular smooth muscle responds to changes in arterial blood pressure.
72
Intrinsic Regulation of Blood Flow:
| What are metabolic control mechanisms?
Vasodilation is controlled by changes in:
1. Decreased oxygen concentrations due to increased metabolism
2. Increased carbon dioxide concentrations
3. Decreased tissue pH (due to CO2, lactic oxide, etc.)
4. Release of K+ and paracrine signals
73
What do the coronary arteries supply blood to?
To a massive number of capillaries (2,500–4,000 per cubic mm tissue)
74
What is different about the heart vs other organs regarding blood flow during systole? What does cardiac tissue do to make up for this?
1. Unlike most organs, blood flow is restricted during systole
2. Cardiac tissue therefore has myoglobin to store oxygen during diastole to be released in systole
75
What standard cellular structures does cardiac tissue have a lot of? What does this mean?
1. Cardiac tissue also has lots of mitochondria and respiratory enzymes
2. It is metabolically very active
76
How much do the coronary arteries increase blood flow from during exercise?
During exercise, the coronary arteries increase blood flow from 80 ml to 400 ml/ minute/100 g tissue
77
Regulation of coronary blood flow:
| What 3 things regulate coronary blood flow?
1. Norepinephrine from sympathetic nerve fibers stimulates vasoconstriction, raising vascular resistance at rest.
2. Adrenal epinephrine stimulates vasodilation and thus vascular resistance during exercise.
3. Vasodilation is enhanced by intrinsic metabolic control mechanisms
78
Regulation of Blood Flow Through Skeletal Muscles:
| Arterioles have ___ vascular resistance at rest.
high
79
Regulation of Blood Flow Through Skeletal Muscles:
| Even at rest, skeletal muscles still receive __- __% of the body’s blood supply.
20-25%
80
Regulation of Blood Flow Through Skeletal Muscles:
| What is vasodilation stimulated by?
by both adrenal epinephrine and sympathetic acetylcholine
81
Regulation of Blood Flow Through Skeletal Muscles:
| Intrinsic metabolic controls _____ vasodilation during exercise
enhance
82
Circulatory Changes During Exercise:
| Vascular resistance to skeletal and cardiac muscles ______
decreases
83
Circulatory Changes During Exercise:
| Vascular resistance to skeletal and cardiac muscles decreases due to what 3 factors?
1. Increased cardiac output
2. Metabolic vasodilation
3. Diversion of blood away from viscera and skin
84
Blood flow to brain ____ a small amount with moderate exercise and ______ a small amount during intense exercise.
1. Increases
| 2. Decreases
85
Cardiac output can increase ___ due to increased cardiac rate.
5X
86
Stroke volume can increase some due to _______ ____ ___.
increased venous return
87
How does the brain handle variation in blood flow?
cannot tolerate much variation in blood flow
88
Unless mean arterial pressure becomes very high, there is ____ sympathetic control of blood flow to the brain.
little
89
At high pressure, vasoconstriction occurs to protect small vessels from ____ and ____.
1. damage
| 2. stroke
90
Myogenic Control of Cerebral Blood Flow:
1. When blood pressure falls, cerebral vessels automatically ____.
2. When blood pressure rises, cerebral vessels automatically ____.
3. Decreased pH of cerebrospinal fluid (buildup of CO2) also causes ____ ____.
1. When blood pressure falls, cerebral vessels automatically dilate.
2. When blood pressure rises, cerebral vessels automatically constrict.
3. Decreased pH of cerebrospinal fluid (buildup of CO2) also causes arteriole dilation.
91
Metabolic Control of Cerebral Blood Flow:
The most active regions of the brain must receive _(1)___ blood flow due to arteriole sensitivity to ____(2) _____.
3. What may also play a role in metabolic control of cerebral flow?
1. increased
2. metabolic changes
3. Astrocytes
92
What can can tolerate the greatest fluctuations in blood flow?
The skin
93
The skin helps control body temperature in a changing environment by regulating ___(1)____.
2. What is this called?
1. blood flow
| 2. Thermoregulation
94
Increased blood flow to capillaries in the skin releases what when body temperature increases?
heat
95
1. What is produced to aid in heat loss?
Bradykinins in the sweat glands also stimulate __(2)___ in the skin
1. Sweat
| 2. Vasodilation
96
Cutaneous blood flow in cold temperatures:
1. __________ of arterioles keeps heat in the body when ambient temperatures are low.
2. This is aided by _______ _______, which shunt blood from arterioles directly to venules.
1. Vasoconstriction
| 2. arteriovenous anastomoses
97
Cutaneous Blood Flow:
Cold temperatures activate ______(1)_______.
2. Why is this tolerated?
1. sympathetic vasoconstriction
| 2. This is tolerated due to decreased metabolic activity in the skin
98
Cutaneous Blood Flow:
1. At average ambient temperatures, vascular resistance in the skin is ____, and blood flow is ___.
2. Sympathetic stimulation _____ blood flow further
3. With continuous exercise, the need to regulate body temperature overrides this, and _____ occurs.
1.
A. High
B. Low
2. Reduces
3. Vasodilation
99
Cutaneous Blood Flow:
1. May result in _____ total peripheral resistance if not for _____ cardiac output
2. However, if a person exercises in very hot weather, he or she may experience ____ ____ in blood pressure after _____ cardiac output.
3. This condition can be ___ ____.
1.
A. Lowered
B. Increased
2.
A. extreme drops
B. reduced
3. very dangerous
100
What 4 factors is blood pressure affected by?
1. Blood volume
2. Stroke volume
3. Total peripheral resistance
4. Cardiac rate
101
Increase in any of the 4 factors blood pressure is affected by (blood volume/stroke volume, total peripheral resistance, and cardiac rate) will do what to blood pressure?
Increase it
102
Vasoconstriction of arterioles does what to blood pressure upstream in the arteries?
Vasoconstriction of arterioles raises blood pressure upstream in the arteries.
103
Is capillary blood pressure low or high?
low
104
Why is capillary blood pressure low?
because of large total cross-sectional area
105
What is the baroreceptor reflex activated by?
changes in blood pressure detected by baroreceptors in the aortic arch and carotid sinuses
106
How does the baroreceptor reflex work?
Increased blood pressure stretches these receptors, increasing action potentials to the vasomotor and cardiac control centers in the medulla.
107
What is the baroreceptor reflex most sensitive to?
Most sensitive to drops in blood pressure
108
Baroreceptor reflex:
1. What controls vasodilation and constriction?
2. What control heart rate?
1. vasomotor center controls
| 2. cardiac center
109
How does a fall in blood pressure affect:
1. Sympathetic activity?
2. Parsympathetic activity?
3. What does all this result in?
4. What does rise in blood pressure?
1. Rise in Sympathetic activity
2. Fall in Parsympathetic activity
3. increased heart rate and total peripheral resistance
4. Opposite effects
110
What is the baroreceptor reflex good for?
Good for quick beat-by-beat regulation
111
What are atrial stretch reflexes activated by? What is the function?
Increased venous return to:
1. Stimulate tachycardia
2. Inhibit ADH release
3. Stimulate secretion of atrial natriuretic peptide
112
The atrial stretch reflex inhibits ADH release. What results because of that?
Results in excretion of more urine
113
The atrial stretch reflex stimulate secretion of atrial natriuretic peptide. What is the result because of that?
Results in excretion of more salts and water in urine
114
What units is blood pressure measured in? What is it measured by?
Measured in mmHg by an instrument called a sphygmomanometer.
115
A blood pressure cuff produces turbulent flow of blood in the brachial artery, which can be heard using a stethoscope; called _____ __ _____.
sounds of Korotkoff
116
Describe how to blood pressure cuff works in 2 steps.
1. The cuff is first inflated to beyond systolic blood pressure to pinch off an artery. As pressure is released, the first sound is heard at systole and a reading can be taken.
2. The last Korotkoff sound is heard when the pressure in the cuff reaches diastolic pressure and a second reading can be taken.
117
What is the average blood pressure?
The average blood pressure is 120/80.
118
Taking the pulse is a measure of what?
heart rate
119
What would a health professional feel when taking the pulse pressure?
What the health professional feels is increased blood pressure in that artery at systole
120
The difference between blood pressure at systole and at diastole is the what?
pulse pressure
121
If your blood pressure is 120/80, your pulse pressure is what?
40 mmHg
122
What is the the mean arterial pressure?
The average pressure in the arteries in one cardiac cycle is the mean arterial pressure
123
Why is the mean arterial pressure significant?
This is significant because it is the difference between mean arterial pressure and venous pressure that drives the blood into the capillaries
124
How is mean arterial pressure calculated?
diastolic pressure + 1/3 pulse pressure
125
What is hypertension?
High blood pressure
126
What percentage of americans have hypertension?
20%
127
What does hypertension increase the risk of?
cardiac diseases and stroke
128
What two ways can hypertension be classified?
1. Essential
| 2. Secondary
129
What is secondary hypertension?
Secondary hypertension is a symptom of another disease, such as kidney disease
130
Do most people have secondary or essential hypertension?
essential
131
Is the cause of essential hypertension easy or difficult to determine?
The cause is difficult to determine
132
What may be involved with the cause of essential hypertension?
1. Increased salt intake coupled with decreased kidney filtering ability
2. Increased sympathetic nerve activity, increasing heart rate
3. Responses to paracrine regulators from the endothelium
133
What are the dangers of hypertension (not cardiac diseases and stroke.. this a more detailed question)
1. Vascular damage within organs, especially dangerous in the cerebral vessels and leading to stroke
2. Ventricular overload to eject blood, leading to arrhythmias and cardiac arrest
3. Contributes to the development of atherosclerosis
134
What are 5 possible treatments for hypertension?
1. Lifestyle modification: limit salt intake; limit smoking and drinking; lose weight; exercise
2. K+ (and possibly calcium) supplements
3. Diuretics to increase urine formation
4. Beta blockers to decrease cardiac rate
5. ACE inhibitors to block angiotensin II production
135
When does circulatory shock occur?
Occurs when there is inadequate blood flow to match oxygen usage in the tissues
136
What do the symptoms of circulatory shock result from?
Symptoms result from inadequate blood flow and how our circulatory system changes to compensate.
137
What does circulatory shock sometimes lead to?
Sometimes shock leads to death.
138
What is hypovolemic shock due to?
Due to low blood volume from an injury, dehydration, or burns
139
What can hypovolemic shock be characterized by?
Decreased cardiac output and blood pressure
140
Where is blood diverted to in hypovolemic shock? At the expense of what?
Blood is diverted to the heart and brain at the expense of other organs
141
What is compensation for hypovolemic shock? What are the results of this?
Baroreceptor reflex:
1. Lowers blood pressure
2. Raises heart rate
3. Raises peripheral resistance
4. Produces cold, clammy skin
5. Produces low urine output
142
What is septic shock?
Dangerously low blood pressure due to an infection (sepsis)
143
What is happening with septic shock?
Bacterial toxins induce NO production, causing widespread vasodilation
144
What is the mortality rate for septic shock?
Mortality rate is high (50−70%)
145
What is anaphylactic shock caused by? What is it due to?
1. Severe allergic reactions
| 2. Due to production of histamine and resulting vasodilation
146
What is neurogenic shock caused by? What is it due to?
1. Spinal cord injury or anesthesis
| 2. Due to loss of sympathetic stimulation
147
What is cardiogenic shock shock caused by? What is it due to?
1. Cardiac failure
| 2. Due to significant myocardial loss
148
When does congestive heart failure occur?
Occurs when cardiac output is not sufficient to maintain blood flow required by the body
149
What are the symptoms of congestive heart failure similar to?
Hypovolemic shock symptoms
150
What are 5 potential causes for congestive heart failure?
Caused by:
1. Myocardial infarction
2. Congenital defects
3. Hypertension
4. Aortic valve stenosis
5. Disturbances in electrolyte levels (K+ and Ca2+)
