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Posted on Aug 25, 2020 in Other subjects

The Vascular System & Blood:

The Vascular System: A network of vessels that transport blood throughout the body; vessels divided into four main categories:

Arteries: carry blood away from the heart to different organs.

  • Very Elastic, can easily stretch and recoil.
  • Blood pressure measured in arteries.

Arterioles: regulate blood distribution to various tissues in the body.

  • Have rings of smooth muscle that can constrict or relax and alter blood flow.
  • Arteriole Muscle is controlled chemically (Autoregulation) and through the nervous system intervention.

Capillaries: responsible for the exchange of gases and nutrients with the tissues via diffusion.

Veins: After capillaries, smaller Venules become larger veins which become the vena cava, which returns blood to the heart.

Arteries:

Are elastic, have more muscle than veins. 

Carryoxygenated blood and nutrients away from the heart (gives brightred colour) to the tissues that require oxygen.

Why is arterial blood pressurized?

Veins:

  • Veins (and smaller venules): Carry deoxygenated blood towards the heart (gives dark red colour).
  • Exceptions are the Pulmonary Veins.
  • Have one-way valves to keep blood moving forward.

The Return of Blood From Veins To The Heart:

The Skeletal Muscle Pump:

  • Upon contraction of skeletal muscle, blood is pushed/massaged back to the heart.

The Thoracic Pump:

  • Pressure in veins (in the chest) decrease while pressure in the veins (in the abdominal cavity) increase upon intake of breath.
  • Difference in pressure pushes blood from veins in the abdominal cavity into veins in the thoracic activity.

The Nervous System:

  • Sends a signal to the veins.
  • Venoconstriction: Veins also have muscle which allows them to constrict, allowing more blood back to the heart.

Cardiac Cycle:

The Cardiac Cycle refers to the series of events that occurs through a single heart beat. During this cycle, there are 2 Events:

  • Diastole: Is the relaxation phase, heart filling with blood.
  • Systole: Heart muscle contracts and ejects blood.

During this cycle, there are dramatic changes in blood pressure, which propel the blood.

  • Blood Pressure is the pressure that the blood exerts on the blood vessel walls as it travels through the body.
  • Changes in blood pressure correspond to the phases of the heartbeat.
  • Systolic Pressure: Maximum pressure in arteries when the ventricles contract and push blood through 120 mmHg (Arteries Stretch).
  • Diastolic Pressure: Lowest pressure in arteries when the ventricles are not contracting and push blood through 80 mmHg (Arteries Recoil).

Blood Pressure & Exercise:

  • Blood Pressure is affected by exercise but changes depend on The Type, Duration & Intensity Of An Exercise.

Exercise Type:Acute Aerobic/Endurance.

  • Blood Pressure: Increase is Systolic which is proportional to the exercise intensity.

Exercise Type: Resistance Training.

  • Blood Pressure: Short but very large increases in both Systolic & Diastolic which is proportional to intensity.
  • Post Workout: Regardless of the exercise type, after completion individuals experience a prolonged period of hypotension.
  • Blood Pressure is a commonly used indicator to measure overall cardiovascular health.
  • Normal blood pressure (BP): 120 mmHg over 80 mmHg.
  • Hypertension: BP greater than 140 mmHg over 90 mmHg. Modifiable Risk Factor for CVD (can be changed through lifestyle).Factors affecting BP: Diet & Aerobic Exercise.

·Blood:

The Fluid of Life.

What colour is blood?

    • Straw with some red pigments.
    • Has Two main components:
    • Plasma: 55% – Fluid component of blood (mostly water) + Nutrients + Proteins + Ions + Gases.
    • Formed Portion: 45% – Solid portion of blood has 3 Components.
  1. Red Blood Cells (Erythrocytes): Made in bone marrow. Transport O2 and CO2 in the blood. Transport nutrients and waste, and contain Hemoglobin.
  2. White Blood Cells (Leukocytes): Destroy foreign elements, critical in the function of the immune system.
  3. Platelets: Regulate blood clotting.

Cardiovascular Dynamics:

    • Deals with how the Cardiovascular System adapts to meet the demands placed on it. Ie: During exercise.

Heart adjusts amount of blood pumped by altering:

    • Heart Rate (HR): Duration of each cardiac cycle. Increases with exercise.
    • Stroke Volume (SV): Volume of blood ejected by the left ventricle in a single beat (mL).

Regulated by:

1) LVEDV

2) Aortic Pressure

3) Strength of Ventricular Contraction : Changes in any of these affect SV.

SV = LVEDV – LVESV

    • Left Ventricle End Diastolic Volume – amount of blood in the left ventricle after the contraction of the left atrium.
    • Left Ventricle End Systolic Volume – amount of blood remaining in the left ventricle after the contraction of the ventricle.
    • Note: Ventricle never empties completely.

oFrank-Starling Law:

      • High LVEDV leads to Ventricular Stretching which causes a more forceful contraction which causes More Blood to be ejected from the ventricle.

Cardiac Output (Q):

      • The volume blood that is pumped out of the left ventricle in 1 minute (L/minute), Rest 5-6L/min, exercise 30 L/min.
      • HR + SV = Q

Ejection Fraction:

      • Is the proportion of blood that is ejected from the left ventricle during a single heartbeat.
      • Increases with exercise.

Cardiovascular Dynamics:

      • The most important factor that regulates Stroke Volume SV is the amount of blood that is returned to the heart! AKA Venous Return.
      • During Exercise, venous return increases as the result of Four Main Factors:
  1. Constriction of the Veins (Venoconstriction):
      • Veins also have small amounts of smooth muscle that contract during exercise, which reduces blood in veins directing it toward the heart.
  1. The Skeletal Muscle Pump:
      • Working Muscles squeeze veins within sending blood to the heart.
  1. The Thoracic Pump:
      • Breathing in and out creates pressure that forces blood through veins.
  1. Nervous Stimulation of the Heart:
      • During exercise it leads to increase HR & increase in force of contraction in the heart.

§Blood Flow Distribution:

        • During exercise, working skeletal muscles have an increased need for O2.
        • The Cardiovascular system has two ways in which they meet the muscle needs:
  1. Increase in Cardiac Output (Q).
  1. Redistribution of Blood Flow:
      • Blood flow is increased to working muscles while being decreased to other less active organs. Ie: stomach, intestine and kidneys.
      • Blood flow is dependent on the intensity of the exercise.
      • The higher the intensity, the more flow to skeletal muscles

The Effects of Training on the Cardiovascular System:

      • Regular Aerobic Training leads to many cardiovascular benefits including:
  1. Alterations in Heart Structure: The heart grows not only in weight but in dimensions.
      • Ventricular Volume increases along with Ventricular Muscle which are likely a result of the constant increase Venous Return seen with training.
  1. Increased Capillaries to the Myocardium.
  2. Increased Diameter of Coronary Arteries.
  3. Increased Blood Volume; Plasma & Erythrocytes.
      • Leads to increased venous return, increased ventricular stretching, increased SV, increased Q, increased ventricular muscle.
  1. Bradycardia:
      • The decrease of HR at rest and during sub-maximal exercise, however still unchanged at maximal exercise 60 bpm or less.
      • 100 bpm or more = Tachycardia.


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The Vascular System & Blood:

The Vascular System: A network of vessels that transport blood throughout the body; vessels divided into four main categories:

Arteries: carry blood away from the heart to different organs.

  • Very Elastic, can easily stretch and recoil.
  • Blood pressure measured in arteries.

Arterioles: regulate blood distribution to various tissues in the body.

  • Have rings of smooth muscle that can constrict or relax and alter blood flow.
  • Arteriole Muscle is controlled chemically (Autoregulation) and through the nervous system intervention.

Capillaries: responsible for the exchange of gases and nutrients with the tissues via diffusion.

Veins: After capillaries, smaller Venules become larger veins which become the vena cava, which returns blood to the heart.

Arteries:

Are elastic, have more muscle than veins. 

Carry oxygenated blood and nutrients away from the heart (gives bright red colour) to the tissues that require oxygen.

Why is arterial blood pressurized?

Veins:

  • Veins (and smaller venules): Carry deoxygenated blood towards the heart (gives dark red colour).
  • Exceptions are the Pulmonary Veins.
  • Have one-way valves to keep blood moving forward.

The Return of Blood From Veins To The Heart:

The Skeletal Muscle Pump:

  • Upon contraction of skeletal muscle, blood is pushed/massaged back to the heart.

The Thoracic Pump:

  • Pressure in veins (in the chest) decrease while pressure in the veins (in the abdominal cavity) increase upon intake of breath.
  • Difference in pressure pushes blood from veins in the abdominal cavity into veins in the thoracic activity.

The Nervous System:

  • Sends a signal to the veins.
  • Venoconstriction: Veins also have muscle which allows them to constrict, allowing more blood back to the heart.

Cardiac Cycle:

The Cardiac Cycle refers to the series of events that occurs through a single heart beat. During this cycle, there are 2 Events:

  • Diastole: Is the relaxation phase, heart filling with blood.
  • Systole: Heart muscle contracts and ejects blood.

During this cycle, there are dramatic changes in blood pressure, which propel the blood.

  • Blood Pressure is the pressure that the blood exerts on the blood vessel walls as it travels through the body.
  • Changes in blood pressure correspond to the phases of the heartbeat.
  • Systolic Pressure: Maximum pressure in arteries when the ventricles contract and push blood through 120 mmHg (Arteries Stretch).
  • Diastolic Pressure: Lowest pressure in arteries when the ventricles are not contracting and push blood through 80 mmHg (Arteries Recoil).

Blood Pressure & Exercise:

  • Blood Pressure is affected by exercise but changes depend on The Type, Duration & Intensity Of An Exercise.

Exercise Type:Acute Aerobic/Endurance.

  • Blood Pressure: Increase is Systolic which is proportional to the exercise intensity.

Exercise Type: Resistance Training.

  • Blood Pressure: Short but very large increases in both Systolic & Diastolic which is proportional to intensity.
  • Post Workout: Regardless of the exercise type, after completion individuals experience a prolonged period of hypotension.
  • Blood Pressure is a commonly used indicator to measure overall cardiovascular health.
  • Normal blood pressure (BP): 120 mmHg over 80 mmHg.
  • Hypertension: BP greater than 140 mmHg over 90 mmHg. Modifiable Risk Factor for CVD (can be changed through lifestyle).Factors affecting BP: Diet & Aerobic Exercise.
  • Blood:

The Fluid of Life.

What colour is blood?

    • Straw with some red pigments.
    • Has Two main components:
    • Plasma: 55% – Fluid component of blood (mostly water) + Nutrients + Proteins + Ions + Gases.
    • Formed Portion: 45% – Solid portion of blood has 3 Components.
  1. Red Blood Cells (Erythrocytes): Made in bone marrow. Transport O2 and CO2 in the blood. Transport nutrients and waste, and contain Hemoglobin.
  2. White Blood Cells (Leukocytes): Destroy foreign elements, critical in the function of the immune system.
  3. Platelets: Regulate blood clotting.

Cardiovascular Dynamics:

    • Deals with how the Cardiovascular System adapts to meet the demands placed on it. Ie: During exercise.

Heart adjusts amount of blood pumped by altering:

    • Heart Rate (HR): Duration of each cardiac cycle. Increases with exercise.
    • Stroke Volume (SV): Volume of blood ejected by the left ventricle in a single beat (mL).

Regulated by:

1) LVEDV

2) Aortic Pressure

3) Strength of Ventricular Contraction : Changes in any of these affect SV.

SV = LVEDV – LVESV

    • Left Ventricle End Diastolic Volume – amount of blood in the left ventricle after the contraction of the left atrium.
    • Left Ventricle End Systolic Volume – amount of blood remaining in the left ventricle after the contraction of the ventricle.
    • Note: Ventricle never empties completely.

oFrank-Starling Law:

      • High LVEDV leads to Ventricular Stretching which causes a more forceful contraction which causes More Blood to be ejected from the ventricle.

Cardiac Output (Q):

      • The volume blood that is pumped out of the left ventricle in 1 minute (L/minute), Rest 5-6L/min, exercise 30 L/min.
      • HR + SV = Q

Ejection Fraction:

      • Is the proportion of blood that is ejected from the left ventricle during a single heartbeat.
      • Increases with exercise.

Cardiovascular Dynamics:

      • The most important factor that regulates Stroke Volume SV is the amount of blood that is returned to the heart! AKA Venous Return.
      • During Exercise, venous return increases as the result of Four Main Factors:
  1. Constriction of the Veins (Venoconstriction):
      • Veins also have small amounts of smooth muscle that contract during exercise, which reduces blood in veins directing it toward the heart.
  1. The Skeletal Muscle Pump:
      • Working Muscles squeeze veins within sending blood to the heart.
  1. The Thoracic Pump:
      • Breathing in and out creates pressure that forces blood through veins.
  1. Nervous Stimulation of the Heart:
      • During exercise it leads to increase HR & increase in force of contraction in the heart.

§Blood Flow Distribution:

        • During exercise, working skeletal muscles have an increased need for O2.
        • The Cardiovascular system has two ways in which they meet the muscle needs:
  1. Increase in Cardiac Output (Q).
  1. Redistribution of Blood Flow:
      • Blood flow is increased to working muscles while being decreased to other less active organs. Ie: stomach, intestine and kidneys.
      • Blood flow is dependent on the intensity of the exercise.The higher the intensity, the more flow to skeletal muscles