Exam 1: Cardiovascular System Flashcards
1
Q
What is Resting Membrane Potential
A
Voltage (charge inside cell) difference across cell membrane when cell is at rest
Intracellular environment is more negative compared to extracellular environment
RMP for neurons is -70 mV
2
Q
What are the different types of tissues
A
Epithelial
connective
muscle
nervous
3
Q
what tissues are excitable (can be stimulated to produce electrical signals)
A
Nerve and Muscle tissues
4
Q
How is action potential triggered
A
by movement of ions
5
Q
REVIEW GRAPH OF AP FROM A&P I
A
6
Q
what are the types of muscle tissue
A
skeletal
smooth
cardiac
7
Q
Describe functions of and characteristics of skeletal muscle
A
functions; locomotion, posture, respiration
It is voluntary and striated
stimulated by motor neurons
8
Q
Describe functions of and characteristics of smooth muscle
A
functions; contraction of hollow organs, vasoconstriction, vasodilation
It is involuntary and non-striated
9
Q
Describe functions of and characteristics of Cardiac muscle
A
function; contraction of heart chambers
only found in heart
involuntary and striated
autorhythmic
10
Q
Define autorhythmic
A
can contract on own without nerve stimulation
11
Q
What components make cardiac muscle unique
A
branched and networked cardiac myocytes that are joined by intercalated discs
mitochondria-rich (1/3 of cell volume)
larger and branched t-tubules
graded contraction
12
Q
What are the components of cardiac myocytes
A
*Desmosomes: strong links between adjacent cells
*Gap junctions: allow waves of depolarization to spread rapidly between cells
13
Q
Define Graded contraction
A
amount of force generated is related to how many cross-bridges are active
-the more cross-bridges (active) = greater force of contraction
*Determined by how much Ca++ bound to troponin
14
Q
Define pulmonary
A
relating to lungs
15
Q
define systemic
A
relating to the entire body
16
Q
In general where do arteries carry blood
A
away from the heart
17
Q
In general where do veins carry blood
A
to the heart
18
Q
What is the physical location of the heart
A
within the mediastinum which is located within the thoracic cavity
19
Q
what is the mediastinum
A
region between pulmonary cavities (lungs)
20
Q
what is the approximate size of the heart
A
the size of a closed fist
21
Q
What factors influence heart size
A
age, height, weight, gender
*this is important for treatment of certain heart conditions and/or problems
22
Q
Describe the hearts shape
A
base = top of heart
apex = bottom where it narrows
*looks like a tilted ice cream cone (point is on person’s bottom left side when viewing anteriorly)
23
Q
Define Pericardium
A
peri = around
cardium = heart
surrounds the heart providing protection and roots great vessels. There are 2 layers to it.
24
Q
Name and describe the superficial layer of the pericardium
A
fibrous pericardium:
-made of dense and loose CT, fairly non pliable
-function: anchors heart, prevents overdistension, protects against blunt force
25
Name and describe the deep layer of the pericardium
Serous Pericardium:
-composed of 2 layers
1. Parietal layer
-outer/fused to fibrous pericardium
2. Visceral layer
-inner/aka epicardium covers heart
26
what is the function of pericardial fluid
found between layers of serous pericardium
Function: reduces friction during heart contraction
27
Define pericarditis
inflammation of the pericardium
*Caused by some viral infections
28
What are the different portions of the heart wall from superficial to deep
Epicardium (AKA visceral pericardium)
Myocardium
Endocardium
29
Describe the Epicardium (visceral pericardium)
superficial, thin, smooth layer of heart wall
30
Describe the Myocardium
Middle layer of heart wall, very thick
-composed of cardiac myocytes (heart muscle cells) that cause contractility
31
Describe the Endocardium
Deep, somewhat thin layer of heart wall
composed of simple squamous epithelium over CT layer
Covers the inner surfaces (chambers) of the heart
smooth texture for easy blood movement
32
How many chambers does the human heart have
4
33
Is blood oxygenated (O2 rich) or deoxygenated (O2 poor) when travelling through the Right side of the heart
Deoxygenated (O2 Poor)
34
Is blood oxygenated (O2 rich) or deoxygenated (O2 poor) when travelling through the Left side of the heart
Oxygenated (O2 Rich)
35
what are the 2 superior chambers of the heart known as
Right and Left Atriums (Atria is proper plural)
36
what are the 2 inferior chambers of the heart known as
Right and Left Ventricles
37
what separates the right and left atria of the heart
interatrial septum
38
what separated the right and left ventricles of the heart
interventricular septum
39
Why are the interatrial and interventricular septums necessary
separate O2 Rich and O2 Poor blood
40
what do the valves of the heart allow
one-way blood flow and prevent back flow of blood
41
What are the cusps/leaflets in the heart
Flaps that are a part of the valves
42
How many atrioventricular (AV) valves are in the heart
2
43
What are the names of the AV valves
tricuspid valve
bicuspid/mitral valve
44
Which side of the heart is the Tricuspid valve on and how many flaps does it have
right side and has 3 flaps
*tri before you bi
45
which side of the heart is the Bicuspid/Mitral valve on and how many flaps does it have
left side and has 2 flaps
46
How many semilunar (SL) valves are in the heart
2
47
what makes each of the SL valves unique
They each have 2 half moon shaped cusps
48
What are the names of the SL valves
Pulmonary semilunar valve
Aortic semilunar valve
49
In terms of blood flow, which side of the heart does blood come from when travelling through the Pulmonary Semilunar Valve
Right Side
(O2 poor blood comes from rest of body via SVC and IVC, travels through RA, Tricuspid valve, RV, then pulmonary semilunar valve, to pulmonary arteries, to lungs)
50
In terms of blood flow, which side of the heart does blood come from when travelling through the Aortic Semilunar Valve
Left Side
(O2 Rich blood comes from lungs via pulmonary veins, travels through LA, Bicuspid valve, LV, then Aortic semilunar valve, to aorta, to rest of body)
51
REVIEW FLOW OF BLOOD GRAPHIC
52
What are Chordae Tendinea and what is its function
connect Atrioventricular (AV) valves, so Tri- & Bi- cuspid, to papillary muscle within heart
Function: prevents inversion of valves during ventricular contraction
53
Describe the coronary arteries
Left and Right Coronary arteries both originate from/exit the aorta
Function: Supply O2 rich blood to heart tissue
54
What are the major branches of the left Coronary A. and what do they supply
Left Anterior Descending artery
-Supplies: anterior left Ventricle
Left Marginal artery
-Supplies: lateral wall of left ventricle
Circumflex artery
-Supplies: posterior wall of heart
55
What are the major branches of the Right Coronary A. and what do they supply
Right Marginal artery
-Supplies: lateral wall of Right Ventricle
Posterior Descending artery
-Supplies: posterior and inferior portions of heart
56
What is the function of the cardiac veins
Drain O2 poor blood from heart tissue
57
what are the major veins (cardiac)
Great Cardiac Vein (L side)
Middle Cardiac Vein (posterior)
Small Cardiac Vein (R side)
58
Where do the major cardiac veins drain to
Coronary sinus
59
What is the function of the Coronary Sinus
collects O2 poor blood from above and empties into right atrium
60
How can a coronary blockage occur
cholesterol and fatty deposits (plaques) build up in artery
61
What can result from coronary blockage
Infarction
62
Define Infarction
Necrosis (tissue death) due to insufficient blood flow
63
What is a Myocardial Infarction
"Heart Attack"
-Necrosis of myocardium due to one or more coronary blockage
*fixed with CABG (Coronary Artery Bypass Graft) surgery
64
what is a "widowmaker" and why is it dubbed this
Blockage of left anterior descending artery
-So serious bc this artery supplies the L ventricle, and if blood cannot get here, it cannot get to the aorta to be pumped to the brain and rest of the body
65
What makes cardiac muscle unique
-It is branched and networked
-joined by intercalated discs
-there is a high level of communication between cardiac myocytes
*this allows for coordinated contraction of cardiac muscle tissue
66
What is cardiac syncytium
arrangement of cardiac myocytes to form an interconnected mass
When one cell becomes excited, all cells become excited and heart can contract as one unit
*"All or nothing" principle*
67
What are the two types of Syncytia in the heart
Atrial syncytium: coordinated contraction of both Atria
Ventricular syncytium: coordinated contraction of both Ventricles
68
What are the types of Cardiac myocytes
Contractile Cells
Autorhythmic Cells
69
what is Autorhythmicity
ability to spontaneously generate action potentials without external nervous system influence
70
Describe the relationship between the different cardiac myocytes
Autorhythmic cells produce action potentials which causes the spread of action potentials through contractile cells
71
Where are autorhythmic cells located
near top of Right Atrium
72
Describe autorhythmic myocytes
autorhythmic cells that fire at their own intrinsic rates
73
what is the most important autorhythmic myocyte
Sinoatrial (SA) node
*located at top of R atrium
74
what are the other autorhythmic myocytes
-Atrioventricular (AV) node
-Bundle of His
*split into: Bundle Branches
-Purkinje fibers
(Run up sides of Ventricles, cause them to contract)
75
Why is the Sinoatrial (SA) node so important
Called the "Pacemaker"
-spontaneously generates APs at regular intervals (~70 BPM)
Medical intervention needed:
*If SA node not functioning: AV node beats at 50 BPM
*If AV node not functioning: Purkinje fibers beat at ~15-30 BPM
76
List the specific sequence of the spread of excitation in Autorhythmic myocytes
1. SA node: signal spreads across atria (0.4s), atria contract
2. AV node: signal delay (0.11s), allows atria to fully empty
3. Purkinje fibers: signal reaches ventricles (0.08s), ventricles contract
77
Describe process of cardiac muscle excitation-contraction coupling
-Action Potential from adjacent cell opens voltage-gated Ca++ channels
-Ca++ enters cell
-Induces Ca++ release from Sarcoplasmic Reticulum
-Ca++ binds to troponin = muscle contraction!
78
What makes Action Potentials in Contractile myocytes unique
-Long refractory period compared to skeletal muscle
*this prevents tetanus (We want repeated contraction, NOT long periods of constant contraction in heart --this is deadly)
79
what is the resting membrane potential in skeletal muscle fibers and contractile cardiac myocytes
-90 mV
80
REVIEW GRAPH OF AP FOR A CONTRACTILE CARDIAC MYOCYTE
81
What are the phases of an AP for a contractile cardiac myocyte
Phase 0=depolarization
-Fast Na+ channels open
*Na+ rushes into cell
-At ~-40mV, L-type Ca++ channels open
*slow and steady Ca++ influx (into cell)
Phase 1=Early Repolarization
-some K+ channels open
*some K+ comes out of cell
Phase 2=Plateau
-More L-type Ca++ channels open
*allows Ca++ into cell
-Also at same time more K+ channels open
*K+ moves out of cell
-------creates plateau (counterbalance of Ca++ in and K+ out)
Phase 3=Repolarization
-Ca++ channels close
-K+ channels still open
*still getting K+ out
Phase 4=Resting Membrane Potential
-All channels are closed
-back to RMP of -90mV
82
what is "pacemaker potential"
Phase 1 of AP in autorhythmic myocytes
-slow positive increase of 'RMP' between APs
-Keeps autorhythmic cells READY to fire at a moment's notice
83
what are the 3 causes of pacemaker potential
1. Increased influx of Na+
-"funny" channels open in response to hyperpolarization
-Allow Na+ into cell, pushes up voltage
2. Decreased efflux of K+
-K+ channels close during hyperpolarization of AP, limiting K+ leaving the cell, pushes up voltage
3. Differential influx of Ca++
-some Ca++ channels open before threshold, pushes voltage to threshold
-once threshold is reached, L-type Ca++ channels open, producing AP
84
REVIEW GRAPH OF AP FOR AN AUTORHYTHMIC CARDIAC MYOCYTE
85
what are the phases of an AP for an autorhythmic cardiac myocyte
Phase 1=Pacemaker Potential
-In hyperpolarized state, "funny" channels open
*Allows Na+ into cell
-As we approach threshold, some Ca++ channels open
*Ca++ into cell
------pushes cell to threshold
Phase 2=Depolarization
-L-type Ca++ channels open
*more Ca++ into cell
Phase 3=Repolarization
-Ca++ channels close
-K+ channels open
*K+ moves out of cell
86
Why are autorhythmic myocytes never truly at rest
As soon as we hit -60mV, pacemaker potential occurs automatically, which triggers rest of AP
87
What is an electrocardiogram (EKG or ECG)
Record of *electrical activity of the heart
(Repolarization and depolarization)
-Electrical events correlate with physical activity
88
what are the different parts of an EKG
P wave
QRS Complex
T wave
89
what *electrical and =physical activity is recorded during the P wave of an EKG
*Depolarization of atria
=onset of atrial contraction
90
what *electrical and =physical activity is recorded during the QRS complex of an EKG
*Depolarization of ventricles
=onset of ventricular contraction
91
what *electrical and =physical activity is recorded during the T wave of an EKG
*Repolarization of Ventricles
=onset of ventricular relaxation
92
How to interpret EKG
-Are all waves present & normal
Ex. QRS for every P
If not: heart block-APs from SA node blocked from reaching ventricles (looks like P waves w/o QRS complex)
Ex. Long QT Syndrome
Lengthy QT interval, affects repolarization of heart
(Causes seizures, fainting, etc.)
93
What is Tachycardia
high heart rate
>100BPM
94
What is Bradycardia
Low heart rate
<60BPM
95
When is heart rate measured to obtain the most accurate value
when resting, not active
96
what is fibrillation sometimes called
"Quiver"
97
what is Atrial Fibrillation (A-fib)
irregular contractions atria
*irregular spacing of QRS complex and no P waves on EKG
-A-fib is compatible with life and full activity
98
How to treat A-fib
Beta blockers
(block beta-adrenergic receptors to drop heart rate and re-establish SA node)
99
what is ventricular fibrillation (V-fib)
EMERGENCY! Results in cardiac arrest
-ventricular twitches instead of proper contractions
-loss of consciousness within seconds
100
how to treat v-fib
FATAL unless intermediate intervention occurs
(CPR and defibrillation)
101
What is a defibrillator
applies a strong electrical current that depolarizes most/entire heart at once
-gives SA node a chance to re-establish normal sinus rhythm
102
Describe the Cardiac cycle
Pattern of contraction and relaxation of heart chambers
-Initiated by spontaneous AP from SA node
103
What role do the atria play in the cardiac cycle
Primer pumps
-push blood into ventricles
104
what role to the ventricles play in the cardiac cycle
power pumps
-"force" blood into pulmonary and systemic circulation
105
Define diastole
Relaxation
-blood fills chamber
106
Define systole
contraction
-blood is pushed out of chamber
107
REVIEW CARDIAC CYCLE GRAPHIC
107
what are the steps of the cardiac cycles
1. Passive filling of atria and ventricles
2. atrial systoles
-blood forced into ventricles
3. ventricular systole
-a. isovolumetric contraction: ventricles contract, blood is not pushed out yet
-b. Ejection:
semilunar valves get pushed open and blood is pushed out of ventricles
4. ventricular diastole
-a. isovolumetric relaxation:
No blood filling ventricles yet
*Go back to 1.*
108
Describe the heart sounds
("lub dup")
1st sound-"lub"=AV valves closing
2nd sound-"dup"=SL valves closing
3rd sound-faint=Turbulent blood flow into ventricles
*don't always hear this one*
109
what is systolic blood pressure
Ventricular contraction forces blood into aorta
-highest pressure in aorta
(120 mmHg pressure)
110
what is diastolic blood pressure
decrease in aortic pressure
-lowest pressure in aorta
(80 mmHg pressure)
111
Describe intrinsic regulation of the heart
Cardiac output (CO)
-amount of blood (volume) pumped per minute
Stroke volume (SV)
-volume of blood pumped per beat
Changes in heart rate (HR) & stroke volume (SV) = changes in cardiac output (CO)
Venous return
-flow of blood back to the heart
-can influence SV and CO
112
what is Starling's law of the heart
stroke volume of left ventricle increases as volume of blood in left ventricle increases
-Due to preload (stretch) of cardiac muscle
-Greater preload=greater force of contraction
113
REVIEW SCENARIO WHERE STARLING'S LAW CAN BE PUT INTO PRACTICE
114
Describe extrinsic regulation of the heart from Sympathetic NS
Sympathetic nervous system
-project to heart as cardiac nerves
-nerves synapse at SA node, AV node, & ventricular myocardium
-secretion of Norepinephrine (NE)
*binds to adrenergic receptors
*increased influx of Ca++ into cardiac myocytes
-excitatory influence (Fight or Flight response)
115
Describe Extrinsic regulation of the heart from Parasympathetic NS
Parasympathetic Nervous System
-Vagus nerve
-synapses at SA node & AV node
-secretion of Acetylcholine (Ach)
*binds to muscarinic receptors
*increased number of K+ in open position, makes depolarization more difficult
-inhibitory influence (rest and digest)
116
What is Vagal tone
represents efficacy of Vagus nerve (parasympathetic) activity
High vagal tone=good
-resilience to stress, Heart rate can be lowered when needed
Low vagal tone=bad
-inability to "relax" the heart
117
what is Heart Rate Variability (HRV)
beat to beat variation in heart rate
High HRV=good
-lots of variability can accommodate a variety of situations
-good adaptability
Low HRV=bad
-associated with frequent stress
-less variation between beats, regularly high HR
*leads to pathology or even fatality
118
Describe arteries
Elastic blood vessels that have lots of smooth muscle
-empty into arterioles, which then empty into capillaries
119
what are capillaries
site of gas/nutrient/etc. exchange with tissues
120
what are veins
blood vessels that have thinner walls, less elastic, less smooth muscle
-receive blood from venules
121
Describe flow of blood between vessels
Heart -> arteries -> arterioles -> capillaries -> venules -> veins -> heart
122
what are the layers of blood vessels from superficial to deep
Tunica externa
Tunica media
Tunica intima
123
What is the function of the Tunica externa and what tissue is it composed of
Tissue: collagenous CT
Function: prevents the vessel from shifting position too much
124
What is the function of the Tunica media and what tissue is it composed of
Tissue: smooth muscle
Function: performs vasodilation and vasoconstriction (changes BP)
125
What is the function of the Tunica intima and what tissue is it composed of
Tissue: endothelium (simple squamous epithelium
Function: helps to regulate capillary exchange and blood flow
126
what are the different capillary types
Continuous capillaries
Fenestrated capillaries
Sinusoidal capillaries
127
Describe Continuous Capillaries
-very common in nearly all tissues
-tight junctions between endothelial cells
*allows for exchange of small molecules like H20, glucose, gasses, and certain hormones
128
Describe Fenestrated Capillaries
-Found in kidneys & small intestines
-Fenestrations (pores) allow the exchange of larger molecules like nutrients, waste products, & large hormones-peptide)
129
Describe Sinusoidal Capillaries
-Rare: found where cells & very large molecules need to be transported (spleen, bone marrow, liver, etc.)
-Contain extensive intercellular gaps
130
what are capillary networks
-final destination of arterial blood from heart
-exchange of materials between blood & other tissues
131
what are portal venous systems
-where capillary bed pools into another capillary bed
-linked by veins
132
How many portal systems exist in the human body
2 portal systems
133
What are the portal systems in the human body and what are their functions
Hepatic Portal system
-directs blood from GI tract to liver
Hypophyseal portal system
-carries hormones from hypothalamus to anterior pituitary
134
what are the regions of the aorta
Ascending aorta
Aortic arch
Descending aorta
-becomes thoracic aorta within thorax & abdominal aorta within abdomen
135
what are the branchings of the aorta from R to L
Brachiocephalic A.
*branches into R. Common Carotid A. & R. Subclavian A.
Left Common Carotid A.
Left Subclavian A.
136
what are the arteries of the head and neck
R & L Common Carotid Aa.
*branch into internal & external carotid Aa.
Circle of Willis-supplies most of blood flow to brain
*internal carotid Aa. and others
Basilar A.
*supplies posterior brain
137
what are the arteries of upper & lower limbs
Major pulse points: upper limbs
-Brachial artery
-Radial artery
Femoral artery
138
Veins of head and neck
internal and external jugular veins
139
Veins of upper and lower limbs
Median Cubital Vein
-common site for blood draws
Saphenous Veins
-often used for coronary artery bypass grafts (CABG)
140
which direction does blood flow in terms of pressure
high pressure to low pressure
141
Describe process of pressure and resistance
Driving pressure (where pressure is lower) from ventricles forces blood into vessels
Blood exerts pressure against walls of blood vessels, but vessels resist against blood flow
Resistance influenced by: Blood viscosity, vessel length, vessel radius
Ventricles have to exert enough force to overcome resistance in blood vessels
BP measures pressure against artery walls
142
What is systolic pressure
pressure of blood against artery walls during ventricular systole (average: 120 mmHg)
what it tells us:
force of contraction of heart
143
What is diastolic pressure
pressure of blood against artery walls during ventricular diastole (average: 80 mmHg)
what it tells us:
condition of systemic blood vessels
*reflects ability to store energy in elastic walls
Ex. increase in diastolic pressure = decrease in vessel elasticity
144
how is arterial blood pressure measured
Auscultatory method
-non-invasive method that uses Korotkoff sounds
145
what are Korotkoff sounds
sounds in vessels due to changes in blood flow from BP cuff
146
what measurements are derived from BP
pulse pressure
mean arterial pressure (MAP)
147
what is pulse pressure
systolic minus diastolic pressure
-represents force that heart generates with each contraction
*Normal: 40-60 mmHg
148
what is mean arterial pressure (MAP)
average pressure in the arteries during one cardiac cycle
*Normal: 70-100 mmHg
149
what is vascular compliance
how much a vessel is able to stretch
-more stretch=greater compliance
Compliant arteries=GOOD
-The more compliant an artery, the more blood flow it can accommodate w/o increasing BP and overtaxing cardiovascular system
Compliance decreases as we age
veins have thinner walls, so more compliant than arteries
150
what is critical closing pressure
pressure where vessel collapses if flow/pressure too low
151
what is shock
occurs from rapid drop in BP
-can cease blood flow
-some blood flow/force is needed to keep vessel open (if we drop below that, vessel can collapse)
-necrosis of tissues if supply lost for too long
152
what is an aneurysm
bulge in vessel
-Radius of vessel and pressure applied is higher here
-can cause vessel to rupture
153
How do veins return blood to heart
Active mechanisms of venous return-
*skeletal muscle pumps:
skeletal muscle contracts, presses on veins, squeezing blood back to heart
*gravity:
returns blood from upper body (head, neck, shoulders)
*respiratory pump:
pressure on thoracic cavity squeeze veins
*one-way valves:
prevent back flow
*smooth muscle:
squeezes blood back to heart
