Cardiovascular System Pt 1 Flashcards
Heart activity and behavior 1
Measuring electrical activity of the heart tied to what the heart is doing
Anatomy and physiology of the heart:
Four chambers
Right and left atria (receive incoming blood)
Right and left ventricles (pump blood out of heart)
Function of the chambers:
Atria
Receive blood from veins
Function of the chambers:
Ventricles
(Right and Left)
Pump blood through arteries to the lungs (R ventricle)
And the rest of the body (L ventricle)
Diagram of heart (from front)
Right atrium (top, on left side) - Left atrium (top, on right side)
Right ventricle (bottom, on left side) - Left ventricle (bottom, on right side)
Right atrium receives blood from
All body tissue except the lungs
Right atrium receives blood from all body tissue except the lungs through (3)
Superior Vena Cava
Inferior Vena Cava
Coronary Sinus
Superior Vena Cava
Blood from upper body
Inferior Vena Cava
Blood from lower body
Coronary Sinus
Blood from the heart itself
Pulmonary Artery
Blood flows from RIGHT ATRIUM to RIGHT VENTRICLE to the lungs by way of the
Oxygenated blood goes to LEFT ATRIUM by
Four Pulmonary Veins
Then it goes to… which pumps through the Aorta to the rest of the body
Left Ventricle
Circulation of blood through the heart
(Superior vena cava/ Inferior vena cava) ➡️ RIGHT ATRIUM ➡️ (Tricuspid valve) ➡️ RIGHT VENTRICLE ➡️ PULMONARY ARTERY ➡️ LUNGS ➡️ LEFT ATRIUM ➡️ (Mitral valve) ➡️ LEFT VENTRICLE ➡️ AORTA ➡️ Rest of the body
Control of heart beat
Electrocardiogram
Heartbeat represents
Contraction of the heart to pump blood to other body organs
Control of beating is both
Intrinsic and extrinsic
What does intrinsic mean?
Related to the heart itself
Cardiac conduction system
Sinoatrial node, Atrioventricular node, Right bundle branch, HIS bundle (same as A-V bundle), Left bundle branch
Intrinsic Mechanisms (4)
Sinoatrial node (aka pacemaker)
Atrioventricular node
Atrioventricular bundle
L and R bundles of conducting fibers
Sinoatrial node (aka pacemaker)
What does it mean?
Contains cells that don’t wait for stimulation/signal, activates themselves
Sinoatrial node (aka pacemaker)
Located in rear wall of R atrium
Electric discharge produces contraction of entire heart
Atrioventricular bundle (2)
Conducts impulse into ventricles
Purkinje fibers conduct impulses for contraction to all parts of ventricles
Contraction phase
Systole
(What happens after contraction of heart muscle, how much pressure leaving the heart)
Relaxation phase
Diastole
Systole measured
In mm Mercury (Hg)
Measuring at level of blood through veins
Which part receives blood?
Right atrium
Extrinsic control (2)
ANS
CNS
Rate of contractions may be influenced by
Extrinsic factors
Extrinsic control:
ANS (2)
Parasympathetic NS
Sympathetic NS
ANS (what I wrote)
Controlling fight or flight
Parasympathetic NS
Influences S-A and A-V nodes by way of CN X (vagus nerve)
Decreases heart rate
Mediated by ACh at vagus nerve endings
Sympathetic NS
Mediated by NE at sympathetic nerve endings
Increases heart rate
Increases rate of S-A node discharge
Increases excitability of heart tissue
Increases force of contraction of atrial and ventricular musculature
Sympathetic NS (what I wrote)
Fight or flight
CNS (3)
Medulla (Baroreceptors)
Hypothalamus (4 Fs- fight, flight, feed, mating, and hormones)
Autonomic nervous system (fight or flight)
Carotid Sinus Reflex
Baroreceptors
Pressure sensitive fibers, Located in neck
Baroreceptors (3)
Ensure adequate blood supply to brain
Supplied by CN IX (Glossopharyngeal)
When Carotid Sinus pressure is low because of low bp, information is sent to medulla which stimulates SNS (sympathetic nervous system) to increase heart rate and bp
Carotid sinus reflex
Back up system to activate heart (only when it drops)
Any kind of trauma (decrease in blood pressure, ex: blood loss)
Carotid sinus reflex diagram
Aortic arch pressure receptors
Hering’s nerves via Glossopharyngeal
Carotid pressure receptors
via Vagus
EKG
Heart contraction accompanied by production of electrical current; can be measured on body surface
EKG (what I wrote)
Measuring cycle heart goes through
Types of waves (3)
P wave
QRS (complex)
T wave
P wave
Currents generated before contraction of atria - Atrial depolarization
QRS (complex)
Current generated in the ventricles during depolarization, just prior to ventricular contraction
QRS (complex) (what I wrote)
To pump blood to the lungs (Right Ventricle) and the rest of the body (Left Ventricle)
T wave
Caused by repolarization of the ventricle
Depolarization and repolarization
Is similar to that which occurs in neurons
Wave diagram
X- axis: Time (s) (0, 0.2, 0.4, 0.6, 0.8)
Y-axis: electrical potential (mV)
P wave in peak in middle of 0 and 0.2
Q at 0.2
R right after at sharp peak
S in middle (low) of 0.2 and 0.4
T in going back up and hill right before 0.6
Wave component Duration
P-Q interval
Time between start of P wave and start of QRS (160 msec)
Q-T interval
Time between start of Q wave and end of T wave (300 msec)
Start of the Next Cycle
Time between end of T wave and the start of the next P wave (370 msec)
Total of Wave Component Duration
160 + 300 + 370 = 830 msec
EKG measures
Heart rate
beats per unit time (ex: bpm)
How is heart rate (bpm) computed?
By counting the number of R peaks within this interval (1 minute)
Heart period
Time between R waves or Inter-beat Intervals (IBI)
Expressed in milliseconds
Heart rate variability
Stability of the HR during baseline or during the performance of a task
EKG Measures (4)
Heart rate
Heart period
Heart rate variability
Respiratory Sinus Arrythmia
Research suggests that as attention demands increase
There is a decrease in HR variation
Respiratory Sinus Arrythmia
HR variability due to respiration
HR increases shortly after respiration begins and decreases shortly after exhalation begins
Heart rate at different ages (2)
1 y/o- 120 bpm
10 y/o- 90 bpm
Adult heart rate at rest male vs female
70 (males)
76 (females)
