Blood and the Cardiovascular System Download

The Cardiovascular System
• Introduction
• 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
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
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
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
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
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
Cardiac Cycle - Systole & Diastole
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
 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 – 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
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
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
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
cut vein – blood flows from the wound
 cut artery – blood spurts from the wound
Physiology of Circulation
 Measuring Blood Pressure
 Systolic pressure
Diastolic pressure
The pressure in the arteries at the peak of ventricular contraction
The pressure when the ventricles are relaxing
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:
Age, weight, race, mood, physical activity, and posture
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
 The Heart, part 1 - Under Pressure: Crash Course A&P #25
Crash Course – Blood Vessels (extras)
 Blood Vessels, part 1 - Form and Function: Crash Course A&P #27
 Blood Vessels, part 2: Crash Course A&P #28
Heart Attack
 Heart attack in 3d animation (4 min)
What happens during a Heart Attack? (10 min)