Cardiovascular System

1
Cardiovascular System

• Purposes of the CV system
• Deliver Oxygen to the tissues
• Carry away waste products from tissues
• Deliver nutrients to the tissues
• Deliver heat to the periphery
• Defend against foreign substances in the body

2
Cardiovascular System
Three Parts of the Cardiovascular System
Blood
Vascular System
Heart
3
Cardiovascular System

• The Blood
• Blood is composed of two parts
• Cellular phase
• Composed of
• 99 red blood cells (RBC)
• White blood cells to combat infection
• Platelets for clotting

Plasma
WBC P
Cell phase
RBC
4
Cardiovascular System

• The Blood
• Two parts
• Cellular phase (cont)
• Hematocrit of whole blood made up of RBCs
• Range 40-45
• Low hematocrit is called anemia

Whole blood 100
Hematocrit 45
5
Cardiovascular System

• The Blood
• Two parts
• Cellular phase (cont)
• Red blood cells contain hemoglobin (Hb)
• Hemoglobin of RBC binds oxygen
• Hemoglobin concentration of blood is 130-150
  grams/liter
• Males is 140-150 g/liter
• Females is 130-140 g/liter

6
Cardiovascular System

• The Blood
• Two parts
• Cellular phase (cont)
• Each gram of Hb carries 1.34 ml of oxygen
• Oxygen carrying capacity of blood (male) 150
  g/L x 1.34 ml/g 200 ml O2 /liter of blood
• Oxygen carrying capacity of blood (female) 130
  g/L x 1.34 ml/g 175 ml O2 /liter

7
Cardiovascular System

• The Blood
• Two parts
• Cellular phase
• Liquid phase
• Called the plasma
• Contains proteins, nutrients, hormones, etc
• 93-94 water

Plasma
8
Cardiovascular System

• The Blood (cont)
• Total Blood Volume is about 4-6 liters
• Cellular volume 2 2.5 liters
• Plasma volume 3 3.5 liters
• Effects of acute exercise on blood volume
• Total volume ? 5-10 due to ? in plasma volume
• Plasma volume decreases due to sweating
• Hematocrit increases
• Effects of chronic training on blood volume
• Blood volume increases 5-10 due to an increase
  in plasma volume
• Hematocrit decreases - psuedoanemia

9
Cardiovascular System

• The Blood (cont)
• Effects of blood doping (pg 507-508)
• Procedure
• Remove 800-1200 ml of blood 50-60 days before
  competition
• Store RBCs frozen
• RBCs are naturally restored by body
• Reinfuse red blood cells 1-2 days before
  competition

10
Cardiovascular System

• The Blood (cont)
• Effects of blood doping (cont)
• Benefits
• Increases hematocrit (RBC concentration)
• Increases Hb concentration
• Increases oxygen carrying capacity
• Increase max VO2
• Increase submaximal endurance

11
Cardiovascular System

• The Blood (cont)
• Effects of altitude exposure (pg 480-485)
• Procedures and changes
• Prolonged exposure for 20 days
• Increase erythropoitin hormone
• Increases RBC
• Increases Hb
• Increases O2 carrying capacity

12
Cardiovascular System

• The Blood (cont)
• Effects of altitude exposure (cont)
• Performance results
• Increase submaximal endurance at altitude
• Does not improve performance at sea level
• Problems
• People at altitude actually detrain because they
  cannot work as intensely at altitude

13
Cardiovascular System

• The Blood (cont)
• Doping with erythropoitin
• Rationale
• EPO stimulates RBC formation
• Increased RBC ? ? Hb ? ? O2 carrying capacity
• ? O2 carrying capacity ? ? performance
• Dangers
• Hematocrit reaches 55-60
• Decreased ability to pump thick blood
• Death from inadequate blood flow

14
Cardiovascular System

• The Heart

Divided into Four Chambers 1. Right Atrium
receives venous blood from body 2. Right
ventricle pumps blood to lungs for
oxygenation 3. Left Atrium receives oxygenated
blood from lungs 4. Left ventricle pumps blood
to body
Left Atrium
Right Atrium
Left Ventricle
Right Ventricle
15
Cardiovascular System
Heart Rate (beats/min)
Non-trained
Max 220-age
What does the graph say?
HR (b/min)
Trained
Rest 60-80 b/min
Intensity of Exercise
16
Cardiovascular System

• Control of Heart Rate
• Two nervous controls via the cardio-regulatory
  center in the medulla
• Sympathetic control via norepinephrine speeds
  up heart rate Accelerator nerve
• Parasympathetic control via acetylcholine
  decreases heart rate vagus nerve
• At the onset of exercise the CRC withdraws the
  vagal stimulus and turns on the sympathetic
  stimulus in order to increase HR to match the
  demands of exercise Central Command Theory
• Nervous control affects the sino-atrial (SA) node
• SA node is the pacemaker of the heart
• SA node can control heart rate without
  innervation
• SA node is about 90-100 b/min

17
Cardiovascular System

• Control of Heart Rate (cont)
• Effects of training
• Increase in PNS (vagal) tone ? decrease in
  resting heart rate and exercise heart rate at
  submaximal intensities
• Other control factors
• Increase body temperature ? increase HR
• Increase adrenaline ? increase HR

18
Cardiovascular System

• Two Phases of the heart beat
• Filling phase resting phase
• Diastole
• During diastole the heart muscle receives its own
  blood flow own oxygen delivery
• Ejection phase
• Systole
• Ventricle muscle contracts forcing blood out of
  the heart
• Training increases diastole which allows increase
  blood flow to the heart muscle increase time
  for oxygen delivery

19
Cardiovascular System

• Stroke Volume
• Definition amount of blood pumped per beat

What does the graph say?
Max 100-110
SV (ml/b)
Rest 60-80
40 VO2 Max
Intensity of exercise
20
Cardiovascular System

• Stroke Volume
• Definition amount of blood pumped per beat

Highly trained
Max 130-180 (T)
Trained
What does the graph say?
Max 100-110 (NT)
Non-trained
SV (ml/b)
Rest 70-90 (T)
Rest 60-80 (NT)
40 VO2 Max
Intensity of exercise
21
Cardiovascular System

• Stroke Volume
• Factors that influence stroke volume
• End Diastolic Volume (EDV) Amount of blood in
  ventricle at end of filling phase
• Function of venous return
• Venoconstriction at onset of exercise squeezes
  blood back to heart
• Muscle pump assists blood flow back to heart
• Respiratory pump assists blood flow back to heart
• More blood in ventricle stretches cardiac muscle
  which results in greater force of contraction
  which results in greater stroke volume

22
Cardiovascular System

• Stroke Volume
• Factors that influence stroke volume (cont)
• Increased sympathetic stimulation
  (norepinephrine) or increased adrenaline in blood
• Increased contractility of heart muscle
• Increased ejection of blood
• Increased ejection fraction from 50 of EDV to
  90 of EDV
• Increased stroke volume
• According to the Central Command Theory,
  sympathetic signals from the CRC stimulate the
  cardiac muscle to increase force of contraction
  to increase stroke volume in order to match the
  demands of exercise

23
Cardiovascular System
Ejection Fraction (Rest NT)
120 ml in
EF 60 SV 72 ml
72 ml out
Diastole
Systole
24
Cardiovascular System
Ejection Fraction (Exercise NT)
140 ml in
EF 79 SV 110ml
110 ml out
Diastole
Systole
25
Cardiovascular System
Ejection Fraction (Resting T)
160 ml in
EF 60 SV 96 ml
96 ml out
Diastole
Systole
26
Cardiovascular System
Ejection Fraction (Exercise T)
200 ml in
EF 90 SV 180 ml
180 ml out
Diastole
Systole
27
Cardiovascular System

• Stroke Volume
• Factors that influence stroke volume (cont)
• Aortic pressure (afterload)
• The pressure against the aortic valve against
  which the ventricle must push in order to open
  the valve
• The less the aortic pressure, the greater the
  stroke volume

28
Cardiovascular System

• Stroke Volume
• Effects of training on factors that affect stroke
  volume
• Increased blood volume ? increase venous return ?
  ? EDV ? ? SV
• Increased ventricle volume ? ? EDV ? ? SV
• Cardiac muscle hypertrophy ? ? force of
  contraction ? ? ejection fraction ? ? SV

29
Cardiovascular System

• Cardiac Output
• C.O. H.R. X S.V.

T
Max 30
NT
Max 20
What does the graph say?
C.O. (L/min)
Rest 5
Intensity of Exercise
30
Cardiovascular System

• Cardiac Output
• C.O. H.R. X S.V.
• 1. Rest (NT) 70 b/min x 70 ml/b 4900 ml/min
  5 L/min
• 2. Rest (T) 55 b/min x 90 ml/b 4900
  ml/min 5 L/min
• 3. Max Ex (NT) 200 x 100 20,000 ml/min 20
  L/min
• 4. Max Ex (T) 200 x 150 30,000 ml/min 30
  L/min
• How much oxygen is being delivered to the tissues
  at rest?
• How much is being consumed at rest?
• How much oxygen is being delivered to the tissues
  at Max exercise?
• How much is being consumed at max Exercise?

31
Cardiovascular System
The Vascular System
Arteries
Arterioles
Capillaries
Venules
Veins
Waste, CO2
O2
Nutrients
32
Cardiovascular System

• The Vascular System
• Blood flow ?P R
• ?P is the change in pressure from the beginning
  of the vascular space to the end
• 120 mm Hg (ventricle) 0 mm Hg (Atrium) 120 mm
  Hg
• Blood flows from high pressure to low pressure
• During exercise systolic blood pressure rises
  from 120 mm Hg at rest to 180-200 mm Hg during
  max exercise due to increased force of
  contraction of the ventricle

33
Cardiovascular System
Blood Pressure at Rest
0 mm Hg
120 mm Hg
Arteries
Arterioles
Capillaries
Venules
Veins
Waste, CO2
O2
Nutrients
34
Cardiovascular System
Blood Pressure at Exercise
0 mm Hg
200 mm Hg
Arteries
Arterioles
Capillaries
Venules
Veins
Waste, CO2
O2
Nutrients
35
Cardiovascular System

• The Vascular System
• Blood flow ?P R (cont)
• R stands for resistance in the system due to
• Length of the system
• Viscosity of the blood
• Radius of the vessels
• The major resistance comes from the vessel radius
• Vasoconstriction increases resistance and
  decreases blood flow
• Vasodilation decreases resistance and increases
  blood flow

36
Cardiovascular System

• The Vascular System
• Arteries, arterioles, venules and veins are lined
  with smooth muscle so that they can be
  constricted or dilated

Smooth muscle
Smooth muscle
Arteriole-Vasoconstricted
Arteriole - Vasodilated
37
Cardiovascular System

• The Vascular System
• Vaso-dilating or vaso-constricting vessels is how
  the body controls blood flow to various organs
  and tissues

Smooth muscle
Smooth muscle
Arteriole Vasoconstricted High Resistance Low
Blood Flow
Arteriole-Vasodilated Low Resistance High Blood
Flow
38
Cardiovascular System

• The Vascular System
• Redistribution of blood flow
• At rest skeletal muscle receives 20 of the blood
  flow
• During exercise active muscle receives up to
  80-85 of the blood flow
• During exercise blood flow is redistributed from
  unused tissues to the skeletal muscle

39
Cardiovascular System

• The Vascular System
• Redistribution of blood flow

40
Cardiovascular System

• The Vascular System
• Control of blood flow during exercise via the
  cardio-regulatory center (CRC) in the medulla
• At the onset of exercise SNS causes
  vasoconstriction of veins which squeezes the
  blood in the veins back to heart, thus increasing
  venous return blood mobilization
• At onset of exercise a general SNS signal causes
  vasoconstriction of arterioles in unused tissues
  but may cause vasodilation in muscle
• Continual SNS during exercise causes
  vasoconstriction of arterioles in all muscles
• Local factors in active muscle over-ride
  vasoconstrictive signal of SNS
• ? O2, ? CO2, ? H, ? Temp, ? Nitric oxide

41
Cardiovascular System

• Cardiovascular System and VO2
• VO2 C.O x (aO2 vO2)
• aO2 is the oxygen concentration of arterial blood
  going to the tissues (ml O2 /L of blood)
• What is the value for aO2?
• vO2 is the oxygen concentration of venous blood
  leaving the tissues (ml O2 /L of blood)
• What is the value for vO2?
• Rest 150 ml/liter
• Exercise 50 ml/liter
• (aO2 vO2) is the amount of oxygen being taken
  up by the tissues from each liter of blood coming
  to the tissues

200 ml/liter
You dont know, so I have to tell you
42
Cardiovascular System

• Cardiovascular System and VO2
• VO2 C.O x (aO2 vO2)

vO2 50 ml O2 /L blood
aO2 200 ml O2 /L blood
(aO2 vO2) 150 ml/L
Muscle
Muscle uses 150 ml of O2 from each liter of blood
(aO2 vO2) is the amount of oxygen being taken
up by the tissues from each liter of blood coming
to the tissues
43
Cardiovascular System

• Cardiovascular System and VO2
• VO2 C.O x (aO2 vO2)
• Sample calculations
• Rest (NT)
• CO 5 L/min
• (aO2 vO2) (200 ml/L 150 ml/L) 50 ml/L
• Rest VO2 5 L/min X 50 ml/L 250 ml/min .25
  L/min (.2-.3 L/min)
• Rest (T)
• the same as NT

44
Cardiovascular System

• Cardiovascular System and VO2
• VO2 C.O x (aO2 vO2)
• Sample calculations (cont)
• Max Exercise (NT)
• CO 20 L/min
• (aO2 vO2) (200 ml/l 50 ml/l) 150 ml/L
• Max VO2 20 L/min X 150 ml/l 3000 ml/min 3
  L/min
• Max Exercise (T)
• CO 30 l/min
• (aO2 vO2) (200 ml/l 25 ml/l) 175 ml/L
• Max VO2 30 L/min X 175 ml/L 5250 ml/min
  5.25 L/min

45
Cardiovascular System

• Cardiovascular System and VO2
• VO2 C.O x (aO2 vO2)
• What are the training adaptations that contribute
  to an increase in max VO2 from 3 liters/min to
  5.25 liters/min?
• ? in oxygen delivery due to an ? in Cardiac
  Output from 20 liters/min to 30 liters/min due
  to
• ? in Stroke Volume
• ? in oxygen use (aO2 vO2) from 150 to 175
  ml/liter due to
• ? in mitochondria in muscle
• ? in capillary density in muscle
• ? in myoglobin in muscle

46
Cardiovascular System

• Summary of the Function of the Cardiovascular
  System during Exercise
• 1. Total blood flow is increased from rest to
  exercise by increasing cardiac output
• 2. The increased blood flow is redistributed to
  working muscle by vasoconstricting arterioles to
  unused areas and vasodilating arterioles to used
  muscle
• 3. The increased blood flow assures an increase
  in the delivery of oxygen and nutrients to
  working muscle in order to support the work while
  carrying away waste products

47
Cardiovascular System

• Some Example Calculations
• From the following values, answer the questions
  below
• HR 150, SV 100, Hb 130, Age 20, vO2 75,
  Systolic blood pressure 160
• What is this persons maximum heart rate?
• What is this persons oxygen carrying capacity?
• What is this persons cardiac output?
• What is this persons oxygen consumption?
• How much oxygen is being delivered per minute?
• Is this person more likely a male or female?

48
Cardiovascular System

• End of Cardiovascular System
• and Exercise

49

• The Blood Blood Components