1. Cardiovascular System

2. How much blood does the heart pump through the body in one given day?
7,000 L blood/day
Why is it important?
If circulation is altered, tissues will lack oxygen & nutrients, and cells will begin irreversible damage

3. Structure of the Heart Lateral: lungs Posterior: vertebral column
Anterior: sternum
Base: superior portion; beneath 2nd rib
Apex: inferior portion; 5th intercostal space

4. Coverings: Pericardium: encloses the heart
visceral: lines the heart itself
parietal: lines the mediastinum cavity
pericardial space: space between visceral & parietal pericardium

5. Wall of the Heart Epicardium: outer layer Fxn: reduce friction
-can have adipose around the coronary arteries and veins
Myocardium: middle layer
Fxn: muscle that actually pumps the blood

6. Endocardium: inner layer
Fxn: perkinje fibers are located here for electrical impulse transmission
-this layer is continuous with the blood vessels

7. Chambers/Valves Atrium (atria): 2 upper chambers of heart
Characteristics:
-thin walls
-receive blood returning to heart

8. Ventricles: 2 lower chambers
Characteristics:
-right ventricle thinner than left
-receive blood from atria
-forces blood into arteries
What divides right and left halves of heart?
Septum

9. What does A-V valve stand for? Atrioventricular Right: tricuspid
Left: bicuspid, or mitral
Remember:
*Arteries bring oxygenated blood away from heart
*Veins bring deoxygenated blood back to the heart

10. Path of Blood Flow: Right atrium Tricuspid valve Right ventricle
Pulmonary valve
Pulmonary trunk
L/r pulmonary arteries
Lungs
Pulmonary veins
Left atrium
Bicupsid (mitral) valve
Left ventricle
Aortic valve
Aorta
….THEN it can go 1 of 2 ways….

11. Which way will it go? Supply the body… Arteries Capillaries Veins
Superior/inferior vena cava
Supply the heart…
Right/left coronary arteries
Capillaries
Coronary veins
Coronary sinus

12. End of

13. Cardiac Cycle: (heartbeat)
Systole: contract
Diastole: relax
Cardiac Cycle: (heartbeat)
Atrial systole/ventricular diastole
Atrial diastole/ventricular systole
All relax
-responds to pressure changes (causes valves to open & fill)
-next one fills as other contracts

14. Heart Sounds Lubb: ventricles contract A-V valves close
Dupp: ventricles relax
Pulm/Aortic valves close
*be sure to read about heart murmurs

15. Cardiac Muscle Fibers
Stimulation to any part will cause heart to contract
Functional syncitium: within atrial and ventricular walls
Fibers work together

16. Cardiac Conduction System
R/l atria contract
A-V node (inf. Septum)
Delay so atria can empty all blood
A-V bundle (bundle of His)
Perkinje fibers (go from IV septum to papillary muscles)
Muscle fibers in v. walls
Sinoatrial node (S-A node)
-located in right atrium
-can initiate impulses
-rhymthmic activity
-”pacemaker”
-located in right atrium near opening to superior vena cava

17. Electrocardiogram (ECG/EKG)
Recording of electrical changes that occur in myocardium during cardiac cycle
Paper moves at specific rate
Between the cycles, pen is on baseline

18. P wave: atrial contraction
QRS complex: ventricular contraction
-electrical changes end
Q wave
R Wave
S Wave
T wave: end of cycle
P-Q interval: SA node through AV node

19. Factors that control heart action/rate:
Brain
-sends message through sympathetic/parasympathetic activity
Temperature
Certain ions
K+ = potassium = decrease rate/force of contractions
Ca+ = calcium = increase heart actions (contract for long time)

20. Arrhythmias Fibrillation: uncoordinated, cardiac chaos
Atrial fibrillation: not life-threatening; blood still pumps (but inefficient)
Ventricular fibrillation (Vfib): often deadly; caused by obstructed artery, toxins, shock, trauma
Flutter: contracts regularly, but very rapidly ( bpm)

21. Other terms: Tachycardia: 100+bpm Bradycardia: 60- bpm
Asystole: myocardium fails to contract
No HR
Flat-lining
Normal Sinus Rhythm: bpm
Normal heart rhythm

22. 62, 000 miles of blood vessels
Arteries:
-carry blood away from heart
-divide into arterioles, and then into capillaries
-higher blood pressure than veins

23. Vasoconstriction: when the diameter of the blood vessel decreases
Vasodilation: when the diameter of the blood vessel increase
**both of the above affect blood flow and pressure

24. Capillaries Smallest-diameter blood vessels
Has a semi-permeable membrane that allow specific gases/nutrients in, while keeping others out

25. Arterioschlerosis: when the walls of affected arteries harden & lose their elasticity
Atheroschlerosis: when fatty deposits form within the vessels
Angioplasty: clears clogged arteries (often with a balloon device)
Bypass surgery: uses a portion of a vein to replace the affected/clogged artery

26. *Blood pressure decreases as the distance from the left ventricle increases
Veins:
-carry blood toward the heart
-contain valves that close if blood begins to back up
-aid in maintaining blood pressure by returning more blood to heart (even with 25% lost)
-generally have thinner walls than arteries

27. Blood Pressure
The force blood exerts against the inner walls of blood vessels
Pressure in the arteries is supplied by the aorta
Arterial BP: pressure increases
Systolic Pressure: maximum pressure
What is normal: 120

28. Ventricular Relaxation: pressure decreases
-Lowest pressure that remains in arteries before next contraction: diastolic pressure
-What is normal? 80
**together, this causes the vessels to expand and recoil = PULSE!

29. Factors that influence blood pressure:
1. Heart Action
-determines volume of blood in vessels
Stroke Volume: volume of blood discharged from left ventricle with each contraction
Cardiac Output: volume discharged from left ventricle per minute
Calculation: SV x HR
*if SV or HR increases, CO increases, and BP increases!

30. Blood Volume
: sum of the formed elements and plasma volumes in the vascular system
Usual amount: 5 liters (8% body in kg)
-blood pressure is directly proportion to blood volume
-if dehydrated, blood pressure drops

31. Peripheral Resistance
Peripheral Resistance :friction between the blood and the walls of blood vessels
-usually hinders blood flow
-vasoconstriction/vasodilation play a big role here
Blood Viscosity
:the ease with which a fluid’s molecules flow past one another
-greater viscosity, greater resistance to flowing
-blood pressure is directly proportional to this

32. How Does One Control Blood Pressure?
Control cardiac output (exercise helps)
Control peripheral resistance (healthy diet, low cholesterol helps with this)

33. What is hypertension? :High blood pressure (usually 140/90)
To what percentage must the heartrate be elevated for exercise to benefit the cardiovascular system?
70-85% of heartrate max
How do you calculate your theoretical maximum (or heartrate max)?
220-age