1. The Cardiovascular System
Anatomy and Physiology
Introduction
The Circulatory System – Bozeman Science

2. Read & Answer (p348-354) Slide 1
Approximately how big is a person’s heart?
What are the 3 layers of the heart wall?
How many chambers make up the heart? Name them.
Put the following in order from inside to outside of the heart. Endocardium, epicardium, myocardium. Which of these contain the cardiac muscles? 350
What is the septum? What are the other 2 names it goes by? 352
Where is blood from the right side of the heart going? Where is blood from the left side of the heart going?
List the 4 valves in the heart and how many cusps each has

3. Define the following Slide 2
Apex 349
Diastole 357
Pericardium 349
Stroke volume 358
Pulmonary circulation 352
Arteries 360
Systemic circulation 352
Arterioles 360
Punkinje fibers 355
capillary beds 360
Sinoatrial node 355
Venules 360
Atrioventricular node 355
Veins 360
Bundle branches 355
Vasoconstriction 374
Tachycardia 357
Bradycardia 357
Systole 357

4. Read & Answer (p352-383) Slide 3
What is cardiac output and how is it calculated? 358
What does the sympathetic and parasympathetic activities do to the heart? 359
Put the following in order from inside to outside of the vessels. tunica externa, tunica intima, tunica media
List 2 structural differences in veins from arteries? 362
What vessels branch from the ascending aorta? What organ is it supplying with blood? 364
Where are the carotid and coronary arteries located? 365
What are the 3 vessels in the umbilical cord? What does each carry? 370

5. Read & Answer (p354-383) Slide 4
What is a pressure point? 372
Put the following in order from highest to lowest pressure? Arterioles, vena cava, arteries, capillaries, veins 372
If blood vessel diameter increased, would blood pressure increase or decrease?
How does blood pressure and osmotic pressure influence substances moving in or out of the capillaries? Which end do substances tend to move in and which end do substances move out? 381
What causes varicose veins? 383

6. Physiology of the Heart
In one day, the heart pushes the body’s 6 liters of blood through the blood vessels over 100 times
Pumps about 6000 liters of blood in a single day

7. Intrinsic Conduction System of the Heart
Cardiac muscles contract spontaneously and independently (even without nervous connections)
Contractions occur in a regular and continuous way
Two systems to regulate heart activity:
Nerves of the autonomic nervous system
Intrinsic conduction system*

8. Intrinsic Conduction System of the Heart
Composed of a special tissue found nowhere else in the body
Cross between muscle and nervous tissue
Enforces a contraction rate of approximately 75 beats per minute – coordinated contractions

9. Intrinsic Conduction System of the Heart
Sinoatrial Node (SA node)
Located in the right atrium
Tiny cell mass
Starts each heartbeat and sets the pace of the whole heart
“pacemaker”

10. Intrinsic Conduction System of the Heart
Atrioventricular Node (AV node)
Located at the junction of the atria and ventricles
Receives the impulse from the SA node
Atria contract
Impulse is delayed to allow the atria to finish contracting

11. Intrinsic Conduction System of the Heart
Atrioventricular Bundle (AV bundle)
Located in the septum
Receives the impulse from the AV node after the delay
Results in the contraction of the ventricles that begins at the apex and moves toward the atria
Contraction ejects blood into the large arteries leaving the heart

12. Intrinsic Conduction System of the Heart

13. Heart Rate Tachycardia Bradycardia Rapid heart rate
Over 100 beats per minute
Prolonged tachycardia may progress to fibrillation
Bradycardia
Slow heart rate
Less than 60 beats per minute

14. Cardiac Cycle and Heart Sounds
Healthy Heart Cycle:
Atria contract simultaneously
As they relax, the ventricles begin to contract
Vocabulary:
Systole – contraction
Diastole - relaxation

15. Cardiac Cycle and Heart Sounds
Cardiac Cycle – the events of one complete heartbeat
Approximately 0.8 seconds
3 Periods:
Mid-to-late diastole
Ventricular systole
Early diastole
Cardiac Cycle - Systole & Diastole
The cardiac cycle

16. Cardiac Cycle and Heart Sounds
Mid-to-Late Diastole
Heart is completely relaxed
Pressure in the heart is low
Blood is flowing passively into and through the atria
Semilunar valves are closed
AV valves are open
Atria contract
Force the remaining blood in their chambers into the ventricles

17. Cardiac Cycle and Heart Sounds
Ventricular Systole
Ventricular contraction begins
Pressure within the ventricles increases rapidly, closing the AV valves
Semilunar valves force open
Blood rushes out of the heart through the large arteries leaving the heart
Atria are relaxed and are filling with blood

18. Cardiac Cycle and Heart Sounds
Early Diastole
Ventricles relax
Semilunar valves shut, preventing backflow
Intraventricular pressure drops
AV valves open

19. Cardiac Cycle and Heart Sounds
Lub, dup, pause
Lub – closing of the AV valves
Dup – seminlunar valves close
First sound is longer and louder than the second

20. Cardiac Output
The amount of blood pumped out by each side of the heart in 1 minute
Product of the heart rate (HR) and stroke volume (SV)
SV – the volume of blood pumped out by a ventricle with each heartbeat
Average cardiac output = 5250mL/min

21. Regulation of Stroke Volume
Anything that increases the volume or speed of venous return increases stroke volume and force of contraction
Exercise, slow heartbeat
Anything decreasing stroke volume causes the heart to beat less forcefully
Blood loss, extremely rapid heart rate

22. Factors Modifying Basic Heart Rate
Emotional or physical stress
Age
Gender
Exercise
Body temperature

23. Average Heart Rate Fetus: 140-160 beats per minute
Adult Females: beats per minute
Adult Males: beats per minute

24. Fetal Circulation
Lungs and digestive system not functional in the fetus
All nutrients, excretory, and gas exchange occurs through the placenta
Nutrients and oxygen move from the mother’s blood to the fetal blood
Fetal waste goes in the opposite direction
fetal circulation

25. Fetal Circulation

26. Physiology of Circulation
Vital Signs
Arterial pulse*
Blood pressure*
Respiratory rate
Body temperature

27. Physiology of Circulation
Arterial Pulse
Caused by expansion and recoil of an artery
Normally equals the heart rate (70-76 per minute resting)
Can be felt in arteries lying close to the body surface
Most common: radial pulse

28. Physiology of Circulation

29. Physiology of Circulation
Blood Pressure
The pressure the blood exerts against the inner walls of the blood vessels
The force that keeps blood circulating continuously

30. Physiology of Circulation
Blood Pressure Gradient
Highest pressure – largest arteries
Pressure drops to zero or negative pressure at the vena cavae
Example
cut vein – blood flows from the wound
cut artery – blood spurts from the wound

31. Physiology of Circulation
Measuring Blood Pressure
Systolic pressure
The pressure in the arteries at the peak of ventricular contraction
Diastolic pressure
The pressure when the ventricles are relaxing
Measurements
Units – mmHg
Systolic over diastolic
Example: 120/80

32. Physiology of Circulation
Variations in Blood Pressure
Systolic: mmHg
Diastolic: 75-80
Varies considerably from person to person
Factors Affecting Blood Pressure:
Age, weight, race, mood, physical activity, and posture
Conditions:
Hypotension: low blood pressure (below 100mmHg)
Hypertension: high blood pressure(above 140/90mmHg)

33. Capillary Exchange of Gases and Nutrients
Substances tend to move to and from body cells according to their concentration gradients
Oxygen and nutrients leave the blood and enter the tissue cells
Carbon dioxide and other wastes exit the tissue cells and enter the blood

34. Capillary Exchange of Gases and Nutrients
Four routes across the capillary wall:
Diffusion across the plasma membrane – lipid soluble
Endocytosis or exocytosis – enter/leave in vesicles
Intercellular clefts – areas of the plasma membrane not joined by tight junctions
Fenestrated capillaries: pores in capillary wall covered by very permeable membrane

35. Crash Course – The Heart
The Heart, part 1 - Under Pressure: Crash Course A&P #25
The Heart, part 2 - Heart Throbs: Crash Course A&P #26

36. Crash Course – Blood Vessels
Blood Vessels, part 1 - Form and Function: Crash Course A&P #27
Blood Vessels, part 2: Crash Course A&P #28