Download Blood and the Cardiovascular System

The Cardiovascular System ANATOMY AND PHYSIOLOGY

• Introduction • https://www.youtube.com/watch?v=NJzJKvkWWDc&ind ex=4&list=PLCC2DB523BA8BCB53 • The Circulatory System – Bozeman Science

Read & Answer (p348-354) Slide 1  Approximately how big is a person’s heart?  Put the following in order from inside to outside of the

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heart wall. endocardium, epicardium, myocardium. Which of these contain the cardiac muscles? 350 How many chambers make up the heart? Name them. 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. 352-353

Define the following Slide 2 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.

Apex 349 Pericardium 349 Pulmonary circulation 352 Systemic circulation 352 Punkinje fibers 355 Sinoatrial node 355 Atrioventricular node 355 Bundle branches 355 Tachycardia 357 Bradycardia 357 Systole 357 Diastole 357

13. 14. 15. 16. 17. 18. 19. 20.

Stroke volume 358 Arteries 360 Arterioles 360 capillary beds 360 Venules 360 Veins 360 Coronary arteries 364 Vasoconstriction 374

Read & Answer (p352-383) Slide 3  What is cardiac output and how is it calculated? 358  What does the sympathetic and parasympathetic 

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activities do to the heart? 359 Put the following in order from inside to outside of the vessels. tunica externa, tunica intima, tunica media 360362 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

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? 373-74  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

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

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* (next slide)

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

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”

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

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

Intrinsic Conduction System of the Heart

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

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

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

 https://www.youtube.com/watch?v=jLTdgrhpDCg 

Cardiac Cycle - Systole & Diastole

 https://www.youtube.com/watch?v=5tUWOF6wEnk 

The cardiac cycle

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

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

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

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

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

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

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

Average Heart Rate  Fetus: 140-160 beats per minute  Adult Females: 72-80 beats per minute  Adult Males: 64-72 beats per minute

Fetal Circulation  Lungs and digestive system not functional in the 

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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 https://www.youtube.com/watch?v=f4SGBSeFwvg 

fetal circulation

Fetal Circulation

Physiology of Circulation  Vital Signs  Arterial pulse*  Blood pressure*  Respiratory rate  Body temperature

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

Physiology of Circulation

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

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 

Physiology of Circulation  Measuring Blood Pressure  Systolic pressure 

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Diastolic pressure 

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The pressure in the arteries at the peak of ventricular contraction The pressure when the ventricles are relaxing

Measurements Units – mmHg  Systolic over diastolic  Example: 120/80 

Physiology of Circulation  Variations in Blood Pressure  Systolic: 110-140mmHg  Diastolic: 75-80  Varies considerably from person to person  Factors Affecting Blood Pressure: 

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Age, weight, race, mood, physical activity, and posture

Conditions: Hypotension: low blood pressure (below 100mmHg)  Hypertension: high blood pressure(above 140/90mmHg) 

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

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

Crash Course – The Heart  https://www.youtube.com/watch?v=X9ZZ6tcxArI&i

ndex=25&list=PL8dPuuaLjXtOAKed_MxxWBNaPn o5h3Zs8  The Heart, part 1 - Under Pressure: Crash Course A&P #25

Crash Course – Blood Vessels (extras)  https://www.youtube.com/watch?v=v43ej5lCeBo&index=2

7&list=PL8dPuuaLjXtOAKed_MxxWBNaPno5h3Zs8  Blood Vessels, part 1 - Form and Function: Crash Course A&P #27

 https://www.youtube.com/watch?v=ZVklPwGALpI&index

=28&list=PL8dPuuaLjXtOAKed_MxxWBNaPno5h3Zs8  Blood Vessels, part 2: Crash Course A&P #28

Heart Attack  https://www.youtube.com/watch?v=T8zkvdkzU7A  Heart attack in 3d animation (4 min)  https://www.youtube.com/watch?v=H_VsHmoRQKk&ebc=ANyPxKrBC-

6dfV3j4caKzRD29KsYRY0hw2AbTR21RV6wHfKnRXHTJMmkz1qufzfZwlWYu x0HiF9UT-X7pKzc6B3h979JyM646A 

What happens during a Heart Attack? (10 min)