Cardiovascular System

Erythrocytes contain hemoglobin which transports oxygen around the body Leukocytes protect the body from disease causing microorganisms/protect the body from getting sick Primary function of platelets is to stop and prevent bleeding.

55% plasma 40% formed elements (erythrocytes, leukocytes, platelets)

Part of the autonomic nervous system which functions to return body systems to rest. Acts on pacemaker to slow down heart rate during recovery.

Part of the autonomic nervous system which prepares the body for action. Sends signal from cardiac centre to pacemaker in response to increased demand of oxygen.

Control centre for regulation of the heart rate

During exercise sympathetic nerves release noradrenalin into SA Node increasing heart rate.

During recovery, parasympathetic system sends impulses down the vagus nerve slowing down heart rate

Prepares the body for action. Reduces blood flow to organs not important to physical activity, and increases blood flow to skeletal/cardiac muscles and lungs.

When deoxygenated blood is pumped from the heart to the lungs where it receives oxygen and is then pumped back to the heart.

Oxygenated blood pumped from the heart to vital organs, muscles and tissues via arteries.

The volume of blood pumped by each ventricle in one minute Cardiac output = stroke volume x heart rate/1000

Volume of blood ejected into pulmonary and aortic arteries in one heart beat

One cardiac cycle

Males have larger hearts than females- larger stroke volume As you age, heart gets smaller- weaker Children have smaller, underdeveloped hearts- low stroke volume, higher heart rate to achieve same cardiac output as adults Trained athletes have larger, stronger hearts than untrained people- higher stroke volume

Heart rate increases during exercise even when the workload has not changed. Causes heart rate to increase, but stroke volume decreases, maintaining consistent cardiac output. Caused by: -increased core body temperature -humidity/ heat -decrease in plasma blood volume due to water loss

Force exerted by blood on arterial walls during ventricular contraction

Force exerted by blood on arterial walls during ventricular relaxation

120 (systolic)/80 (diastolic)

Dynamic exercise keeps diastolic blood pressure low and raises systolic a bit. Static exercises raises both diastolic and systolic significantly

Person tries to exhale when mouth and nose are closed. This causes intrathoracic pressure as blood pressure increases from body’s effort to overcome high internal pressures.

Depends on needs of specific tissues. At rest, kidney and liver receive half of cardiac output. Skeletal muscle receives 15-20% of cardiac output. During exercise, skeletal muscle blood distribution increases to approx 80%

Ventricle hypertrophy- left ventricle gets bigger, allows stroke volume to increase and heart rate to decrease Capillarization- formation of capillaries over the muscles to increase amount of blood/oxygen/nutrients that get to the muscles A-vo2 diff- difference of oxygen content in the arterial and venous blood

VO2 max represents functional capacity of the oxygen transport system and is sometimes referred to as maximal aerobic power or aerobic capacity. Maximal amount of oxygen a person can consume per minute when working to exhaustion.

High cardio causes higher heart rate, heavier breathing and more oxygen in body. Arm ergometry and other static/low cardio exercises will not increase heart rate as much- less oxygen.