Exam 1 Review Flashcards
(76 cards)
1
Q
What is autorhythmicity?
A
- Does not require conscious intervention to elicit cardiac muscle to contract
- Sets its own rhythm without need for input from the nervous system
2
Q
Where is the SA node located?
A
- In upper atrium
- Slightly inferior and lateral to superior vena cava
3
Q
Depolarization rate of SA node under normal conditions
A
- 60+ times per minute
- Fastest intrinsic rate of depolarization
4
Q
Where is the AV node located
A
Posterior and medial to tricuspid valve
5
Q
Depolarization rate of AV node under normal conditions
A
- ~40 times per minute
- Slower then SA node
6
Q
Which node is the pacemaker of the heart?
A
SA node
7
Q
Parts of an ECG
A
- P wave
- QRS complex
- T wave
8
Q
P wave
A
Depolarization of all cells in atria except SA node
9
Q
QRS complex
A
- Ventricular depolarization
- Masks atrial repolarization
10
Q
Parts of QRS complex
A
- Q wave
- R wave
- S wave
11
Q
Q wave
A
First downward deflection
12
Q
R wave
A
Large upward deflection
13
Q
S wave
A
Following downward deflection
14
Q
T wave
A
- Occurs after S wave of QRS complex
- Ventricular repolarization
15
Q
R-R Interval
A
- Duration of generation and spread of action potential through heart
- Can be measured to determine heart rate
16
Q
P-R Interval
A
- Time it takes for depolarization generated by SA node to spread through atria to ventricles
- Includes AV node delay
17
Q
Q-T Interval
A
Action potentials spread through ventricular cells
18
Q
S-T Segment
A
Flat because it is recorded during plateau phase of ventricles
19
Q
Bradycardia
A
Heart rate under 60 BPM
20
Q
Tachycardia
A
Heart rate over 100 BPM
21
Q
Sinus tachycardia
A
Regular, fast rhythm
22
Q
Phases of cardiac cycle
A
- Ventricular filling phase
- Isovolumetric contraction phase
- Ventricular ejection phase
- Isovolumetric relaxation phase
23
Q
Which valves are closed during the ventricular filling phase?
A
Pulmonary and aortic valves
24
Q
Which valves are closed during the isovolumetric contraction phase?
A
All 4 valves
25
Which valves are closed during the ventricular ejection phase?
AV valves
26
Which valves are closed during the isovolumetric relaxation phase
All 4 vavles
27
What produces the heart sounds
When the AV valves close and when the aortic and pulmonary valves close
28
Heart rate
Number of beats per minute
29
Stroke volume
Volume of blood pumped in one heartbeat
30
Cardiac output
Heart rate x stroke volume
31
End-systolic volume
- ESV
- Amount of blood in ventricle at the end of contraction
- Afterload
32
End-diastolic volume
- EDV
- Amount of blood in ventricle after is has filled during diastole
- Preload
33
Resting stroke volume
EDV - ESV
34
Ejection fraction
- Percentage of blood ejected with each ventricular systole
- SV/EDV
- Normally 50-65%
35
Factors that influence stroke volume
- Preload
- Heart contractility
- Afterload
36
Preload
- Length of sarcomeres in ventricular cells before they contract
- Largely determined by EDV
37
Factors that influence EDV
- Length of diastole
| - Venous return
38
EDV increases when
- Diastole is longer
| - Venous return increases
39
What is blood pressure?
Outward force that blood exerts on walls of blood vessels
40
Peripheral resistance
Any factor that hinders blood flow through vasculature contributes to overall resistance
41
Where is resistance greatest?
- Further away from the heart
| - Vessels near heart contribute little to overall resistance
42
What happens to blood pressure as peripheral resistance increases?
BP increases
43
What happens to resistance when blood vessel radius changes?
- Radius increases --> Resistance decreases
| - Radius decreases --> Resistance increases
44
How does viscosity impact resistance?
More viscosity has more resistance
45
How does blood vessel length impact resistance?
Longer --> greater resistance
46
What kind of nervous system stimulation causes vasoconstriction?
Sympathetic nervous system narrows blood vessels
47
Components of blood
- Plasma
- Buffy coat
- Erythrocytes
48
Which component forms the majority of blood?
Plasma
49
Hematocrit
Percentage of blood by volume composed of erythrocytes
50
What is plasma mostly made of?
90% water
51
Shape of RBC
Biconcave disc
52
Function of RBC
Transport of oxygen and carbon dioxide through blood
53
Where do RBC's form?
Hematopoietic stem cells (HSC) in red bone marrow
54
What is the lifespan of erythrocytes?
100-120 days
55
How long does erythropoiesis take?
5-7 days
56
What do HSCs differentiate into?
Progenitor cells called erythrocyte colony-forming units (CFUs)
57
What do erythrocyte CFUs differentiate into?
Proerythroblasts
58
What causes CFUs to differentiate into proerythroblasts?
When the kidneys secrete the hormone erythropoietin
59
What do proerythroblasts become?
Erythroblasts
60
What happens to erythroblasts?
They reject the shrinking nucleus and becomes a reticulocyte
61
What happens to reticulocyte?
Becomes an erythrocyte
62
Where do erythrocytes go to be destroyed?
Erythrocytes become trapped in sinusoids of spleen
63
What happens to erythrocytes in the spleen?
Spleen macrophages digest erythrocytes
64
Categories of leukocytes
- Granulocytes
| - Agranulocytes
65
Which leukocytes are most common?
Neutrophils
66
Which leukocyte is least common?
Basophils
67
Where do platelets come from?
Megakaryocytes
68
What vitamin is needed for coagulation?
Vitamin K
69
How do anticoagulants work?
They inhibit coagulation
70
Anticoagulants
- Antithrombin III
- Heparin sulfate
- Protein C
71
Antithrombin III
- Protein that binds and inhibits activity of both factor Xa and thrombin
- Prevents activation of new thrombin
72
Heparin sulfate
Polysaccharide that enhances antithrombin acitivity
73
Protein C
- Activated by protein S
| - Catalyzes reactions that degrade clotting factors Va and VIIIa
74
What is the vascular spasm?
Begins immediately when a blood vessel is injured and blood leaks into the extracellular fluid
75
Why does vasoconstriction occur in the vascular spasm
Decreases local blood pressure and blood flow
76
Steps of hemostasis
Vascular Spasm --> Platelet Plug Formation --> Coagulation --> Clot Retraction --> Thrombolysis
