1. The Circulatory System
The Heart, Blood Vessels, Blood Types

2. The Closed Circulatory System
Humans have a closed circulatory system, typical of all vertebrates, in which blood is confined to vessels and is distinct from the interstitial fluid.
The heart pumps blood into large vessels that branch into smaller ones leading into the organs.
Materials are exchanged by diffusion between the blood and the interstitial fluid bathing the cells.

3. The Cardiovascular System
Three Major Elements – Heart, Blood Vessels, & Blood
1. The Heart- cardiac muscle tissue
highly interconnected cells
four chambers
Right atrium
Right ventricle
Left atrium
Left ventricle

5. Pathway of the blood Superior Vena Cava Right Atrium Tricuspid Valve
Right Ventricle
Pulmonary Semilunar Valve
Lungs
Pulmonary Vein
Bicuspid Valve
Left Ventricle
Aortic Semilunar Valve
Aorta
To the bodies organs & cells

6. Circuits Pulmonary circuit Systemic circuit
The blood pathway between the right side of the heart, to the lungs, and back to the left side of the heart.
Systemic circuit
The pathway between the left and right sides of the heart.

7. The Cardiovascular System
2. Blood Vessels -A network of tubes
Arteriesarterioles move away from the heart
Elastic Fibers
Circular Smooth Muscle
Capillaries – where gas exchange takes place.
One cell thick
Serves the Respiratory System
VeinsVenules moves towards the heart
Skeletal Muscles contract to force blood back from legs
One way values
When they break - varicose veins form

9. The Cardiovascular System
3. The Blood
Plasma
Liquid portion of the blood. Contains clotting factors, hormones, antibodies, dissolved gases, nutrients and waste

10. The Cardiovascular System
The Blood
B. Erythrocytes - Red Blood Cells
Carry hemoglobin and oxygen. Do not have a nucleus and live only about 120 days.
Can not repair themselves.

11. The Cardiovascular System
The Blood
C. Leukocytes – White Blood cells
Fight infection and are formed in the bone marrow
Five types – neutrophils, lymphocytes, eosinophils, basophils, and monocytes.

12. The Cardiovascular System
The Blood
D. Thrombocytes – Platelets.
These are cell fragment that are formed in the bone marrow from magakaryocytes.
Clot Blood by sticking together – via protein fibers called fibrin.

13. Disorders of the Circulatory System
Anemia - lack of iron in the blood, low RBC count
Leukemia - white blood cells proliferate wildly, causing anemia
Hemophilia - bleeder’s disease, due to lack of fibrinogen in thrombocytes
Heart Murmur - abnormal heart beat, caused by valve problems
Heart attack - blood vessels around the heart become blocked with plaque, also called myocardial infarction

14. Cardiovascular System
Unit 9 – The Heart
Cardiovascular System
The Heart

15. Functions of the Heart Generating blood pressure Routing blood
Heart separates pulmonary and systemic circulations
Ensuring one-way blood flow
Heart valves ensure one-way flow
Regulating blood supply
Changes in contraction rate and force match blood delivery to changing metabolic needs

16. Size, Shape, Location of the Heart
Size of a closed fist
Shape
Apex: Blunt rounded point of cone
Base: Flat part at opposite of end of cone
Located in thoracic cavity in mediastinum

17. Heart Cross Section

18. Pericardium

19. Heart Wall Three layers of tissue
Epicardium: This serous membrane of smooth outer surface of heart
Myocardium: Middle layer composed of cardiac muscle cell and responsibility for heart contracting
Endocardium: Smooth inner surface of heart chambers

20. Heart Wall

21. External Anatomy Four chambers Auricles Major veins Major arteries
2 atria
2 ventricles
Auricles
Major veins
Superior vena cava
Pulmonary veins
Major arteries
Aorta
Pulmonary trunk

22. External Anatomy

23. Coronary Circulation

24. Heart Valves Atrioventricular Semilunar
Tricuspid
Bicuspid or mitral
Semilunar
Aortic
Pulmonary
Prevent blood from flowing back

25. Heart Valves

26. Function of the Heart Valves

27. Blood Flow Through Heart

28. Systemic and Pulmonary Circulation

29. Heart Skeleton
Consists of plate of fibrous connective tissue between atria and ventricles
Fibrous rings around valves to support
Serves as electrical insulation between atria and ventricles
Provides site for muscle attachment

30. Cardiac Muscle
Elongated, branching cells containing 1-2 centrally located nuclei
Contains actin and myosin myofilaments
Intercalated disks: Specialized cell-cell contacts
Desmosomes hold cells together and gap junctions allow action potentials
Electrically, cardiac muscle behaves as single unit

31. Conducting System of Heart

32. Depolarization of muscle fibers = contraction of muscles
Cardiac Conduction
Electrical impulses generate action potentials.
Depolarization of muscle fibers = contraction of muscles
Polarization of muscle fibers = relaxation of muscles
The SA node receives electrical impulses. This SA node is located on the upper right atrium.
This node serves as the hearts pacemaker, regulating the pace and initiating the beat sequence.
Electrical impulses from the SA node spread throughout both atria and the muscle fibers depolarize , causing them to contract (pushing blood into the ventricles) (Atrial Systole)

33. Cardiac Conduction https://www.youtube.com/watch?v=RYZ4daFwMa8
The AV node is located on other side of right atrium .
The AV node Serves as the gateway to the ventricles.
It delays the passage of electrical impulses to the ventricles. So that the atria have ejected all the blood into the ventricles before ventricles contract.
AV node receives signals from the SA node and passes
them onto the atrioventricular bundle, the bundle of HIS.
This bundle is divided into right and left branches and
conducts the impulses towards the apex of the heart. The signals are then passed onto Purjinje fibers, turning upward, spreading throughout the ventricular myocardium.
As the signal spreads through the ventricles, muscle fibers depolarize and contract, pushing blood to lungs and aorta.

34.
Another good video

35. Electrical stimuluses’ of the heart can be recorded in the form of an ECG, electrocardiogram or EKG.
Action potentials through myocardium during cardiac cycle produces electric currents than can be measured
Pattern
P wave
Atria depolarization
QRS complex
Ventricle depolarization
Atria repolarization
T wave:
Ventricle repolarization

36. What does the ECC show about the Heart?
When the atria are full of blood the SA node fires, electrical signals spread throughout the atria and cause them to depolarize. This is represented by the P wave on the ECG. Atrial contraction (systole ) starts about 100ms after the P wave begins.

37. Cardiac Arrhythmias Tachycardia: Heart rate in excess of 100bpm
Bradycardia: Heart rate less than 60 bpm
Sinus arrhythmia: Heart rate varies 5% during respiratory cycle and up to 30% during deep respiration
Premature atrial contractions: Occasional shortened intervals between one contraction and succeeding, frequently occurs in healthy people

38. The PQ segment represents the time the signals travel from the SA node to the AV node.
The QRS complex marks the firing of the AV node and represents ventiricular depolarization (contraction) ( systole)
Q corresponds to the depolarization of the interventricuoar septum.

39. . R wave is produced by depolarization of the main mass of the ventricles.
S wave represents the last phase of ventricular depolarization at the base of the heart.
During the QRS wave the Atrial repolarization occurs but can’t be seen due to the big QRS wave.

40. ST complex represents the myocardial action potential
ST complex represents the myocardial action potential. This is when the ventricles contract and pump blood.
The T wave represents ventricular repolarization immediately before ventricular relaxation (diastole)
The cycle repeats itself with every heartbeat.

41. Alterations in Electrocardiogram

42. Cardiac Cycle
Heart is two pumps that work together, right and left half
Repetitive contraction (systole) and relaxation (diastole) of heart chambers
Blood moves through circulatory system from areas of higher to lower pressure.
Contraction of heart produces the pressure

43. Cardiac Cycle

44. Heart Sounds First heart sound or “lubb” Second heart sound or “dupp”
Atrioventricular valves and surrounding fluid vibrations as valves close at beginning of ventricular systole
Second heart sound or “dupp”
Results from closure of aortic and pulmonary semilunar valves at beginning of ventricular diastole, lasts longer
Third heart sound (occasional)
Caused by turbulent blood flow into ventricles and detected near end of first one-third of diastole

45. Location of Heart Valves

46. Mean Arterial Pressure (MAP)
Average blood pressure in aorta
MAP=CO x PR
CO is amount of blood pumped by heart per minute
CO=SV x HR
SV: Stroke volume of blood pumped during each heart beat
HR: Heart rate or number of times heart beats per minute
Cardiac reserve: Difference between CO at rest and maximum CO
PR is total resistance against which blood must be pumped

47. Factors Affecting MAP

48. Regulation of the Heart
Intrinsic regulation: Results from normal functional characteristics, not on neural or hormonal regulation
Starling’s law of the heart
Extrinsic regulation: Involves neural and hormonal control
Parasympathetic stimulation
Supplied by vagus nerve, decreases heart rate, acetylcholine secreted
Sympathetic stimulation
Supplied by cardiac nerves, increases heart rate and force of contraction, epinephrine and norepinephrine released

49. Heart Homeostasis Effect of blood pressure
Baroreceptors monitor blood pressure
Effect of pH, carbon dioxide, oxygen
Chemoreceptors monitor
Effect of extracellular ion concentration
Increase or decrease in extracellular K+ decreases heart rate
Effect of body temperature
Heart rate increases when body temperature increases, heart rate decreases when body temperature decreases

50. Baroreceptor and Chemoreceptor Reflexes

51. Baroreceptor Reflex

52. Chemoreceptor Reflex-pH

53. Effects of Aging on the Heart
Gradual changes in heart function, minor under resting condition, more significant during exercise
Hypertrophy of left ventricle
Maximum heart rate decreases
Increased tendency for valves to function abnormally and arrhythmias to occur
Increased oxygen consumption required to pump same amount of blood