Unit 1: The Cardiovascular System (Lecture) Flashcards
1
Q
_______ ________ delivers blood to each organ system
A
systemic circulation
2
Q
Oxygen and nutrient rich blood
A
Arterial blood
3
Q
In the circulatory tree blood is delivered to the organ system in __________
A
parallel
4
Q
Which side of the heart ejects blood into the aorta?
A
Left
5
Q
__________ ___________ delivers blood to the lungs
A
Pulmonary circulation
6
Q
Oxygen and nutrient poor blood
A
Venous blood
7
Q
Where must venous blood pass through before entering into systemic circulation?
A
Lungs
8
Q
Blood leaving the pulmonary circulation enters the…
A
Left atrium
9
Q
Right and left pulmonary arteries pass ________ blood
A
venous
10
Q
Right and left pulmonary veins pass __________ blood
A
arterial
11
Q
Atrio-ventricular valves are located…
A
Between atria and ventricles
12
Q
Semilunar valves are located…
A
Between the left ventricle and aorta
Between the right ventricle and pulmonary trunk
13
Q
_________ muscles are specialized muscles that originate in the ventricular wall
A
Papillary
14
Q
Papillary muscles attach to the AV valve flaps via tendon like structures known as _______ ________
A
Chorda tendinae
15
Q
What contracts at the same time as the ventricles?
A
The papillary muscles
16
Q
The aortic and the pulmonary semilunar valves are _________ dependent
A
Pressure
17
Q
Cardiac output
A
The amount of blood pumped by the ventricles per minute
18
Q
At rest, the left and right ventricles each pump about ___ liters of blood per minute.
A
5
19
Q
Cardiac output increases to as much as ____ liters/minute during maximal exercise.
A
30
20
Q
The muscle tissue of the heart is supplied with blood from the…
A
Coronary circulation
21
Q
The right and left coronary arteries originate on the…
A
ascending aorta
22
Q
The right coronary artery supplies the…
A
- Sinoatrial (SA) node
- Atrioventricular (AV) node
- Parts of the right atrium
- Interventricular septum
- Right ventricle
- Left ventricle
23
Q
The ___________ branch originates on the right coronary and supplies the anterior portions of the right ventricle
A
Marginal
24
Q
The ____________ ____________ branch originates on the right coronary and supplies the posterior portions of both ventricles.
A
Posterior interventricular
25
The left coronary artery supplies the...
- Sinoatrial (SA) node
- Parts of the left atrium
- Interventricular septum
- Ventricles
26
The __________ branch supplies the left atrium and posterior regions of the left ventricle.
Circumflex
27
The __________ __________ branch originates from the left coronary and anterior portions of both ventricles.
Anterior interventricular
28
________ _______ vein drains the anterior heart
Great cardiac
29
The ________ _________ vein drains the posterior heart.
Middle cardiac
30
The great and middle cardiac veins drain into the _________ ________
Coronary sinus
31
The coronary sinus drains into the ________ _________
Right atrium
32
The left semilunar valve can't open until it reaches what pressure level (average adult human)?
100 mmHg
33
The right semilunar valve can't open until it reaches what pressure (average adult human)?
35 mmHg
34
What does pressure dependent mean?
Valves that take a certain amount of pressure to open
35
What are the other names for the left atrio-ventricular (AV) valve?
Biscuspid or mitral
36
What is the other name for the right atrio-ventricular (AV) valve?
Tricuspid
37
Heart filling, open valves
Diastole
38
Contracted, close valves
Systole
39
Striated fibers
actin and myosin packaged in myofibrils
40
The sarcomere contains...
Z discs, A bands and I bands
41
In cardiac muscle there is typically one centrally located _________
nucleus
42
There is one ________ per sarcomere
T-tubule
43
Desmosomes
Physical coupling of adjacent cells
44
Gap junctions
Electrical coupling
45
Intercalated discs
structures that connect adjacent cardiac muscle cells
46
The myocardium is considered a...
functional syncytium
47
Syncytium
A syncytium is a single cell that contains multiple nuclei.
A network of cardiac muscle cells connected by gap junctions that allows coordinate contraction of the ventricles
48
Gap junctions
intercellular connections that directly connect the cytoplasm of two cells, which allows various molecules, ions and electrical impulses to directly pass through a regulated gate between cells
49
What allows for electrical impulses to pass quickly from one cell to the next and throughout heart muscle?
Gap junctions
50
Cardiac pacemaker
Sino atrial (SA) node, mass of cells in the right of the atrial wall
51
In the heart, what spontaneously discharges action potentials?
Pacemaker cells in the sino atrial (SA) node and the atrio-ventricular (AV) nodes
52
The atria and ventricles must contract in a...
coordinated fashion
53
What is the first even in the sequence of cardiac muscle excitation?
Depolarization of the sino-atrial (SA) node
54
After depolarization of the SA node, action potentials then...
travel down and across both atria, causing atrial muscle fiber contraction.
55
At the AV border there is a band of...
poorly-conducting tissues (small fibers, few gap junctions)
56
What is the effect of the delay at the AV border?
Provides the atria enough time to empty before muscle contraction.
57
Pacemaker cells discharge action potentials spontaneously at the rate of...
100-120 per minute
58
Our resting heart rate is controlled by the...
Autonomic/Parasympathetic nervous system
59
Our resting heart rate is controlled by the...
Autonomic/Parasympathetic nervous system
60
Plateau
Decline in K perm, increase in CA perm
61
In physiology, refractory refers to...
The period of time when a muscle or nerve cell is unresponsive to stimulation
62
The absolute refractory period refers to the time when...
the cell will not response regardless of the strength of stimulus
63
How long does the refractory period in the heart muscle last?
250 ms
64
Blood enters the right ventricle via...
The right atrium and tricuspid valve
65
The SA node discharges the action potentials spontaneously at the rate of...
100-120 times/minute
66
In a healthy young adult, the resting heart rate is...
70 beats/min
67
The blood entering the right atrium is...
Mixed venous blood
68
________ is the period of ventricular relaxation and filling
Diastole
69
________ is the period of ventricular contraction and blood ejection
systole
70
Atrial diastole
The atria fill passively.
In diastole, both AV valves are open and blood flows into the ventricles.
71
Ventricular diastole
Starts with ventricular muscle repolarization, and with a drop in the ventricular pressure that results in passive filling of the ventricle
72
Atrial systole
Brief synchronous contraction of the atria; active filling of the ventricles
73
Ventricular systole
When the AV valves close and the pressure within the ventricles begins to rise as the cardiac muscle fibers are depolarized and then contract
74
Preload
End-diastolic volume
75
Afterload
Aortic or pulmonary pressure
76
Contractility
Force with which the ventricles contract
77
Principle determinants of stroke volume
- Preload
- Afterload
- Contractability
78
Factors of EDV
- Driving pressure
- Muscle pump
- Respiratory pump
79
Driving pressure
Filling of the heart chambers when there is a pressure differential
80
Respiratory pump
Breathing affects venous return through changes in right atrial pressure
81
Muscle pump
Venous return, when body muscles are relaxed the blood valves are closed. When we contract our muscles, their valves open.
82
Passive contractility
Changes in contractility due to changes in the length of cardiac muscle fibers
83
Active contractility
Change in heart muscle contractility due to stimulation of the heart by nervous system input
84
During active contractility, sympathetic neurons release ________
Norepinephrine
85
Chronotropy
Increased heart rate
86
Inotropy
increase force of cardiac muscle contraction
87
Norepinephrine increase permeability of the cardiac muscle fibers to...
Ca
88
The release of norepinephrine causes an increase in...
1. heart rate
2. force of cardiac muscle contractility
3. number of actin/myosin cross bridge interactions
4. strength of cardiac contraction
89
Each cardiac cycle has a duration of
0.8 seconds
90
Cardiovascular control centers are located in the...
caudal medulla
91
Cardio-accelatory (fight or flight)
Sympathetic NS
92
Cardio-inhibitory (rest and digest)
Parasympathetic NS
93
Effects on the heart rate are called...
Chronotropic effects
94
Circulating hormones
Epinephrine
Thyroxine
95
SNS preganglionic neurons release ______ onto postganglionic neurons
Acetylcholine (ACh)
96
SNS postganglionic neurons release __________ onto target cells
Norepinephrine (NE)
97
NE activates ________ receptors which have a wide-spread effect on cardiac nervous and muscle tissue
beta-1 receptors
98
What in the cardio-accelatory center synapse upon preganglionic neurons in the thoracic spinal cord?
Sympathetic neurons
99
Which neurons synapse onto postganglionic neurons located in the sympathetic chain ganglia?
Preganglionic SNS neurons
100
Which neurons send axons to the SA and AV nodes, and cardiac muscle?
Postganglionic SNS neurons
101
Which neurons send axons to the heart in the vagus nerves?
Parasympathetic NS
102
Which nerves synapse directly on the SA and SA nodes, and on the atrial muscle?
Vagus nerves
103
Which nerves release ACh onto the postsynaptic cells and slow heart rate?
Vagus nerves
104
What causes an increased rate of depolarization in the SA and AV nodes?
Increase in inward NA current
105
Heart rate is modified by:
- emotions
- cortical input
- circulating hormones
106
Hypocalcemia
Reduced ionic calcium depresses contractility
107
Hypercalcemia
Dramatically increases heart rate irritability and leads to spastic contractions
108
Hypernatremia
Excess Na blocks heart contraction by inhibiting ionic calcium transport
109
Hyperkalemia
Excess of potassium leads to heart block and cardiac arrest
110
How do oxygen and nutrients exit the blood?
Capillaries
111
When nutrients exit a capillary, what do they enter?
Interstitial fluid
112
Do carbon dioxide and metabolic waste move in the same or opposite direction as nutrients?
Opposite
113
A network of capillaries where exchange of materials with the tissue cells can take place
Capillary bed
114
Every tissue cell is within ____ cell diameters of a capillary
2-3
115
The average capillary length is...
1 mm
116
The capillary lumen diameter is about...
0.8 micrometers
117
Blood flow velocity in a capillary is about...
0.1-0.3 cm/sec
118
Capillary density in a given tissue is proportional to that tissue's...
metabolic activity
119
What passes the capillary wall via intercellular clefts?
water and water-soluble "solutes"
120
What can cross a capillary wall through endothelial cell membranes?
Small molecules and gases
121
What can cross a capillary wall through fenestrations?
Large molecules
122
Capillary:
- least permeable
- tight junctions between endothelial cells
- intercellular clefts allow the passage of small molecules
Continuous capillaries
123
Location of continuous capillaries
- lungs
- skeletal muscle
- connective tissue
124
Capillary:
- Pores/fenestrations
Fenestrated capillaries
125
Location of fenestrated capillaries
- Kidney
- Endocrine glands
- Small intestine
126
Capillary:
- Large fenestrations
- Few tight junctions
- Wide intercellular clefts allow for the exchange of large molecules
(Discontinuous) Sinusoidal capillaries
127
Location of sinusoidal capillaries
- Liver
- Spleen
- Bone marrow
- Pituitary gland
128
Movement of molecules or ions from a region of higher concentration to one of lower concentration until equilibrium is reached
Diffusion
129
Diffusion is a ______ process
passive
130
Refers to the movement of a fluid from a region of higher pressure to one of lower pressure
Bulk flow
131
Bulk flow is a ______ process
passive
132
Substances enter pinocytotic vesicles, move to endothelial cells via endocytosis, and exit on the opposite side via exocytosis
Transcytosis
133
Transcytosis is a _______ process
active
134
Forces favoring movement of fluid out of the capillary into the interstitial fluid
Blood hydrostatic pressure
Interstitial fluid osmotic pressure
135
Blood hydrostatic pressure
pushed fluid out through the capillary pores
136
Interstitial fluid osmotic pressure
pulls fluid out of the capillary via osmosis
compared to BHP this pressure is very small
137
Blood colloid osmotic pressure
Differences in protein concentration between plasma and ISF.
Tends to pull water from the ISF into the capillary.
138
Interstitial fluid hydrostatic pressure
pressure exerted by interstitial fluid, but typically is very small
139
Refers to the net movement of fluid determined by the difference between the inward and outward pressure
Net filtration pressure
140
The main determiners of fluid movement across the capillary wall
Blood hydrostatic pressure
Blood colloid osmotic pressure
141
____ results in a constant flow of fluid that washes over the tissue cells at the arterial end of the capillary, carrying nutrients and oxygen with it
filtration
142
_____ results in a return of fluid to the capillary at the venous end, thereby depositing wastes into the venous system
reabsorption
143
Under normal conditions, slightly more fluid leaves than is returned by...
capillaries
144
Hemodynamics
the study of fluid flow in the vascular system
145
If blood pressure was equal throughout the CV system...
blood would not flow
146
The pressure difference between regions is termed...
driving pressure
147
BP in large elastic arteries near the heart is...
pulsatile
148
BP peaks during...
systole
149
BP falls during...
diastole
150
Arterial BP reflects...
two features of arteries near to the heart
151
Which vessel is elastic and compliant?
Large arteries
152
Arterial compliance
stretch
153
Elasticity
Recoil
154
Alternating waves of expansion and recoil result in a pressure wave called...
pulse pressure
155
Stiff arteries are less...
compliant
156
To eject the same volume into the circulation, pressure must...
increase
157
Hypertension results when arteries become...
stiffer
158
Pressure in the pulmonary circuit are much ____ than those in the systemic circuit
lower
159
Pulmonary circulation is highly...
compliant
160
The mean pressure in the pulmonary artery at rest is about...
14 mmHg
161
The mean left atrial pressure is about...
5 mmHg
162
Blood flow is proportional to the...
driving pressure
163
Blood flow is inversely proportional to...
the resistance to flow
164
Blood flow =
driving pressure / resistance
165
Resistance is the sum of all forces that...
retard flow
166
Resistance to fluid flow is caused by...
friction between the molecules in the fluid and with the walls of the tubes
167
Frictional resistance...
reduces flow
168
Resistance =
viscosity * vessel length / radius^4
169
Mean arterial pressure =
Diastolic BP + 1/3 (Systolic BP - Diastolic BP)
170
Pulse pressure =
Systolic BP - Diastolic BP
171
Refers to changes in vessel diameter due to circulating hormones
Humoral regulation
172
Regulation of blood vessel diameter by substances released by tissue cells and which is a function of the level of tissue metabolic activity
Metabolic or "local" regulation
173
Increase HR and contractility
sympathetic vasomotor neurons
174
Parasympathetic neurons decrease…
HR
175
Regulate blood vessel diameter
sympathetic vasomotor neurons
176
What synapse onto arteriolar smooth muscle to regulate vasoconstriction?
Sympathetic nerves
177
Cardiovascular neurons receive peripheral afferent input from...
- baroreceptors
- chemoreceptors
- proprioceptors
178
Baroreceptors
Blood pressure
179
Chemoreceptors
Chemical composition
180
Proprioceptors
body position and location of space
181
What are "more important" receptors in cardiovascular regulation?
Baroreceptors and chemoreceptors
182
High pressure baroreceptors are located in the...
carotid sinus and aortic arch
183
Input from the high pressure baroreceptors is carried to the CV center via...
Cranial nerve IX
Cranial nerve X
184
Low pressure baroreceptors are located in...
the right atrium and vena cavae
185
Input from low pressure baroreceptors is carried to the CV center via...
Cranial nerve X
186
Chemoreceptors in the carotid sinus reach the CV center in the medulla via...
cranial nerve IX - glossopharyngeal
187
Chemoreceptors in the aortic arch reach the CV center in the medulla via...
cranial nerve X - vagus
188
Chemoreceptors respond to increased...
Hydrogen ion content
CO2
189
Chemoreceptors respond to reduced...
O2 (hypoxia)
190
Chemoreceptor stimulation activates the SNS and results in increased...
HR, SV, and vasoconstriction
191
(NE and E) circulate and bind directly to receptors on cardiac muscle fibers and on smooth muscle cells of blood vessels
Catecholamines
192
Increase HR and SV, and constriction of veins and arterioles
Catecholamines
193
Which vessels are not subject to vasoconstriction by SNS or catecholamines?
Arteries supplying the brain and heart
194
Arteries supplying the brain and heart...
autoregulate
195
Produced in the hypothalamus with increases in Na concentration blood
Antidiuretic hormone
196
Causes widespread vasoconstriction in case of extremely low BP
Antidiuretic hormone
197
Causes water retention by kidneys
Antidiuretic hormone
198
Causes intense vasoconstriction when renal perfusion is inadequate
Angiotensin II
199
Causes water retention and increase blood volume
Aldosterone
200
Release of renin by the kidney causes...
lowered blood pressure
201
What converts renin into angiotensin I?
Angiotensinogen
202
Where is angiotension converting enzyme located?
Endothelial cells of the lung
203
What is one of the most powerful vasoconstrictor substances?
Angiotensin II
204
What regulates secretion of aldosterone?
Angiotensin
205
Elevated angiotensin II levels cause...
aldosterone secretion by the adrenal cortex
206
What promotes salt and water re-absorption by the kidneys?
Aldosterone
207
Substances that lower blood pressure?
Histamines
208
Released by mast cells cause vasodilation by relaxing blood vessel smooth muscle
Histamine
209
Wastes move in the ______ direction
reverse
210
Clear, straw colored watery liquid that consists of 91.5% of H2O and 8.5% solutes
Plasma
211
Cells and cell fragments
formed elements
212
Where are plasma proteins created?
liver
213
Albumin
maintains blood osmotic pressure
214
immunoglobins
antibodies that bind antigens
215
Fibrinogen is for...
clottin
216
Normal female hematocrit range
38-46%
217
Normal male hematocrit level
40-54%
218
Anemina
Insufficient erythrocytes or not enough hemoglobin
219
Polycythemia
Too many erythrocytes (greater than 65%)
220
Causes of polycythemia
Dehydration
Tissue hypoxia
Blood doping
221
The binocave shape of erythrocytes (RBCs) increases the surface area available for...
oxygen binding
222
The protein that carries oxygen
hemoglobin
223
Each hemoglobin molecule can carry __ O2 molecules
4
224
Oxygen is loaded onto hemoglobin in...
lung capillaries
225
Blood concentration of Hb in women
14 g / 100 ml
226
Blood concentration of Hb in men
16 g / 100 ml
227
Erythropoiesis
Formation of erythrocytes (RBCs)
228
Where does erythropoiesis occur?
red bone marrow
229
After birth, RBCs are formed from...
stem cells
230
During erythropoiesis, stem cells differentiate into...
proerythroblasts
231
Proerythroblasts become...
reticulocytes
232
During erythropoiesis, at maturity reticulocytes...
eject the nucleus then form Hb
233
Regulates differentiation and proliferation of blood cells
erythropoietin
234
Worn out cells removed by...
fixed macrophages in spleen and liver
235
RBCs only live...
80-120 days
236
How is globin broken down into amino acids?
By macrophages in the liver or spleen
237
What is heme broken down into?
Fe and biliverdin
238
How is iron transported in the blood?
the protein transferrin
239
Where is iron stored?
liver, muscle, or spleen
240
When iron is stored, what is it attached to?
Ferritin or hemosiderin protein
241
Biliverdin is converted into...
bilirubin
242
Bilirubin is secreted by...
liver into bile
243
Bile is excreted via...
kidneys and intestine
244
Cell fragments that circulate for 5-9 days before they die
Thrombocytes
245
What percent of mature platelets circulate?
2/3
246
What percent of thrombocytes reside in the spleen?
1/3
247
Clot formation
Thrombosis
248
Thrombus
clot
249
A circulating clot is referred to as an...
embolus
250
TPO is released from the...
liver
251
EPO is released from the...
kidney
252
Severe uncontrolled bleeding
hemorrhage
253
Series of reactions designed to stop bleeding
Hemostasis
254
3 phases of hemostasis
- Vascular spasm (vasoconstriction)
- Platelet plug formation
- Coagulation (blood clotting)
255
Two main functions of thrombin
- Convert fibrinogen into fibrin mesh
- Activates factor XIII which stabilizes fibrin network
256
Where are clotting factors synthesized?
Liver
257
Which vitamin is necessary for clotting factors?
Vitamin K
258
Individuals lacking factor VIII
hemophiliacs
259
Dissolution of a clot
Fibrinolysis
260
What digests fibrin strands to break down a clot?
Plasmin
