Chapter 9 - Circulatory System

Circulatory System works with what other body system?

Pulmonary System

Cardiorespiratory system functions:

• Transport O₂ and nutrients to tissues

• Removal of CO₂ wastes from tissues

• Regulation of body temperature

During Exercise what happens to blood flow

• Increased Cardiac Output

• Redistribution of blood flow from inactive organs to active muscle

Heart function

Create pressure to pump blood

• 2-pump model (heart and lungs)

Arteries and arterioles function…

• Away from the heart

• closed loop system to generate BP and maintain flow

Capillaries function…

Exchange of O₂, CO₂, and nutrients with tissues

Veins and venules function?

Cary blood toward the heart

Pulmonary circuit is on what side of the heart?

Right side

Pulmonary circuit function..

• Pumps deoxygenated blood to the lungs via pulmonary arteries

• Returns oxygenated blood to the left side of the heart via pulmonary veins

Systemic circuit is on what side of the heart?

Left side

Systemic circuit function…

• Pumps oxygenated blood to he whole body via arteries

• Returns deoxygenated blood to the right side of the heart via veins

3 layers of the heart wall

• Epicardium

• Myocardium

• Endocardium

Myocardial infarction (MI) definition…

• aka.. Heart Attack

• Blockage in coronary blood flow results in cell damage and death

• Exercise training protects against heart damage during an MI

Myocardium qualities:

• Must pump blood to entire body

• Has the thickest walls (hypertrophy)

• LV hypertrophies with both exercise (stronger heart) and disease (larger but weaker heart)

Myocardium fiber type

One fiber type (similar to type I)

• high capillary density

• high number of mitochondria

• striations

Cardiac muscles are connected (juxtacrine signaling) by _____ _______

intercalated discs

Skeletal muscle cells qualities and functions:

• Large, long, unbranched, multinucleated

• Intermittent, voluntary contractions

• Ca²⁺ released from SR

Myocardial cells qualities and functions:

• Small, short, branched, one nucleus

• Continuous, involuntary rhythmic contractions

• Ca²⁺ released from SR and Extracellular calcium

How is regular exercise cardioprotective?

• Reduces incidence of heart attacks

• improves survival from a heart attack

• exercise reduces damage from a heart attack!

How does exercise reduces the amount of myocardial damage from heart attack?

• Improvements in heart’s antioxidant capacity

• Improved function of ATP-sensitive potassium channels

Systole

• Contration phase

• Ejection of blood

  • approximately 2/3 blood is ejected from ventricles per beat

Diastole

• Relaxation phase

• Filling with blood

At Rest is diastolic time longer or systolic?

Diastolic time is longer

During exercise what happens o the duration of cardiac cycles?

Duration of both systole and diastole are shorter

Pressure changes during cardiac cycle (diastole)

• Pressure in ventricles is low

• Filling with blood from atria

  • AV valves open when ventricular P < atrial P

Pressure changes during cardiac cycle (systole)

• Pressure in ventricles rises