1. Volume and pressure increases in the atria as they fill by receiving blood from the vena cava and pulmonary veins.
2. A-V valves open when the atrial pressure exceeds the ventricular pressure.
3. Blood flows into the relaxed ventricles. This is 70% of filling. Where is the 30%?
4. Ventricles contract closing the A-V valves and atria relax and start to fill, and increase in pressure opens the semi-lunar valves.
5. Blood is ejected from the ventricles.
6. Ventricles relax, with arterial pressure exceeding the ventricle and semi-lunars close.
When do voltage changes occur
When the heart muscles depolarizes and repolarizes
Where voltage changes occur due to good conduction
Voltage changes can be transformed into wave form recording in what?
Instrument used to make recordings of electocardiogram
P wave meaning
Depolarization of atria
QRS wave complex meaning
Repolarization of atria
T wave meaning
1st heard sound caused by
LUB caused by ventricular contracting and A-V valves closing, louder sound
2nd heart sound caused by
DUP, caused by contraction of aorta and pulmonary artery and the semi-lunar valves closing
Systolic and diastolic pressures are measured only where?
Why are systolic and diastolic pressures measured only in the left ventricle?
BP and blood ejection changes are due to specific physical events during cardiac contraction cycle and to closing/opening of the mitral and aortic valves on left side of heart
Pulmonary intercostal space
Aortic intercostal space
Mitral intercostal space
Tricuspid intercostal space
Right side, 4 and 5
Abnormal heart sound
Volume of blood that flows from either the right or left ventricle of an animal during a given period of time
Sum of the volumes of blood ejected from both ventricles over period of time
Total cardiac output
Increase or decrease in heart rate but implies increase or decrease in function of other organ functions
Increases all heart activities
Decreases heart beat
Stretch receptors located in these two places will respond to increase/decrease in blood pressure
Aortic arch and carotid sinus
Impulses from aortic arch are transmitted via this nerve
Vagus (10th cranial)
Impulses from carotid sinus are transmitted via this nerve
Glossopharyngeal (9th cranial)
Homeostasis maintained by variations of BP, respiration, and vascular responses which are controlled by..?
10th cranial nerve
9th cranial nerve
BP increased Respiration Increased =
During exercise the stretch receptors transmit impulses through the vagus nerve to the centers (cardio-inhibitory & vasomotor) of the brain resulting in an overall effect to generally increase all activities of the heart and circulatory efforts.
BP decreased Respiration decreased =
Dynamic process where pressure waves resulting from cardiac contraction are transmitted through blood vessels
Difference between diastolic and systolic pressure
Mean arterial pressure
Diastolic pressure plus 1/3 of PP
Requires catheterization of peripheral artery
More practical for day to day use for finding BP
Primary methods of indirect blood pressure determination
2) Oscillometric technique
Only measure systolic pressure
Part of the transducer that emits a series of high- frequency sound waves based on arterial blood flow to another transducer
Instrument amplifier box
Part of the transducer that converts the sound wave to an audible sound
Disadvantages of the doppler
MAP not determined
PP not determined
No diastolic pressure so cannot determine in hypo/hypertension
Machine used to demonstrate oscillometric technique
Oscillation amplitude increases until what is reached
What is paramount to uniform measurements of BP
Position of patient
What percentage of limb circumference should cuff be?
How to prepare surface of animal when using transducer
Apply coupling gel
If cuff is too wide it will result in what
If cuff not wide enough will result in
Higher readings and it will pop off
3 factors that effect BP
Natural movement of limbs
Pressure of cuff width
Hypotension can result in
Administration of various meds
Most common complication of anesthesia
Prolonged hypotension leads to
Hypoxia, cerebral hypoxia, and cardiac muscle ischemia
Manifestations of hypotension
Little to not urine output
Retinal vessels become twisted resulting in retinal edema, hemorrhage, and blindess
Blood vessel walls become thick leading to reduced blood flow with damage to nephrons
Enlargement of left ventricle leads to reduced blood flow, arteries constrict to increase blood pressure
Left ventricular hypertrophy
Two classifications of hypertension
Diseases known to cause hypertension
Highest point of arterial pressure obtained where
Peak of left ventricle contraction (systole)
Lowest pressure in arteries occurs when
Left ventricle relaxed (diastole)
BP expressed in what measurement
Blood vessels reduce the blood flow but increase the BP
Blood vessels increase the blood flow and decrease the blood pressure
Oxygen reduced its concentration the blood vessels dilate and more blood is permitted to flow so that oxygen is replenished
Refers to the physical factors associated with the exchange of fluid between the blood and interstitial fluid at level of the capillaries