Cardio vascular system

Pulmonary circuit

Carries deoxygenated blood to the lungs and oxygenated blood back to the heart

Systematic circuit

Carried oxygenated blood to the body and deoxygenated blood back to the heart

Oxygenated blood

Blood rich in oxygen and poor in carbon dioxide

Deoxygenated blood

Blood poor in oxygen and rich in carbon dioxide

Conduction system

Five structures that pass electrical impulses through the cardiac muscle in a coordinated fashion

Myogenic

Generates its own electrical impulses

Diastole

Relaxation phase of the heart

Systole

Contraction phase of the heart

ECG meaning

Electrocardiogram

What is ECG for

Monitoring heart rate and Checking heart defects

Bradycardia

Resting heart rate under 60bpm

Stroke volume

Volume of blood ejected from heart in one beat

Venous return

Amount of blood returning to atria

Heart rate

Amount of beats per minute

Calculation to find a persons HR max

220-age

Cardiac output

amount of blood pumped out of the heart per minute

The conduction system sequence

1. SA node

2. AV node

3. Bundle of His

4. Bundle branches

5. Purkyne fibres

SA node

Internal pacemaker that generates electrical impulses

AV node

Collects and delays cardiac impulse to allow atrial systole

Bundle of His

In the septum and it Feeds impulse from atria to the ventricles

Bundle branches

Splits impulse into the base of each ventricle

Rest Stroke volume for athletes

100ml

Stroke volume =

Stole volume = end diastolic volume - end systolic volume

Rest SV untrained

70ml

SV sub max untrained

100-120ml

SV max untrained

100-120ml

Resting Heart rate for athletes is

50bpm

SV submax athlete

160-200ml

SV max athlete

160-200

Rest HR untrained

70-72bpm

HR submax untrained

100-130bpm

HR submax athlete

95-120

HR max untrained

220-age

HR max athlete

220-age

Untrained rest CO (Q)

5 L/min

Untrained submax CO

10-15 L/min

Untrained max CO

20-30 L/min

Trained resting CO

5 L/min

Trained sub max CO

15-20 L/min

Trained max CO

30-40 L/min

Cardiac output =

Q=SVxHR

CO and SV plateau at higher intensities because

Of the heart rate limiting factor which limits the amount of filling rate

Starlings law

An increased venous return will increase the stoke volume due to greater stretch on the ventricle walls and a harder contraction

Calculation triangle

Couch potato

Sedentary individual

HR response to exercise

1. Rise bc of adrenaline

2. Rapid increase to pump oxygenated blood to muscles

3. plateau because oxygen supply meets oxygen demand

4. Rapid decrease in recovery

5. Slowly decreases but remains above resting HR

HR controlled by

Autonomic nervous system

ANS parts

• Sympathetic increases HR by accelerator nerve

• Parasympathetic decreases HR by vagus nerve

Where is cardiac control centre located

Medulla oblongata

Neural receptors

• Chemoreceptors

• Propioreceptors

• Baroreceptors

Chemoreceptors

Detect changes in chemicals

• pH

• O2

• CO2

Propioreceptors

Detect movement

Baroreceptors

Detect blood pressure in aorta

Intrinsic

• Temperature

• Venous return

Temperature effect on HR

Increase in temp increases blood viscosity and speed of nerve impulses which increases HR

Increase venous return on heart rate

Increases HR because increased stretch on ventricles increases stroke volume

Hormonal mechanism

adrenaline

Adrenaline

Increases ventricle contraction force and increases speed of nerve impulses which increases HR

Venous return mechanisms

• Gravity

• Pocket valves

• Skeletal muscle pump

• Respiratory pump

• Smooth muscle in veins

Pocket valves

Only allow blood flow one way to prevent black flow through veins

Skeletal muscle pump

Squeezes veins and forces blood back to Heart

Smooth muscle in veins

Squeezes veins and pumps blood through them and encourages blood flow

Blood pooling

When blood accumulates in the extremities muscles will squeeze the vein to force the blood out

Result of blood pooling immediately after exercise

Fainting or light headed

How does an active cooldown reduce blood pooling

Maintains venous return by keeping skeletal muscle pump and respiratory pump working and active

How does increased venous return affect performance in sport

Maintains or increases sport performance

What controls VSM

Sympathetic nervous system

Which two receptors give feedback on whether blood flow should be altered

• Chemoreceptors

• Baroreceptors

What part of the medulla oblongata is responsible for the VSM

the vasomotor control centre (VCC)

VSM meaning

Vascular shunt mechanism

What is the vascular shunt mechanism

Controls the redistribution of blood flow from one area of the body to another

What is controlled sympathetically to make the vascular shunt mechanism work

• Arterioles

• Pre-capillary sphincters

Arterioles at muscles

Open during exercise and closed during recovery

Arterioles at other organs

Closed during exercise and open during recovery

Pre-capillary sphincters at muscles

Open during exercise and closed during recovery

Pre-capillary sphincters at other organs

Closed during exercise and open during recovery