Recap on the cardiovascular system and its response to

exercise

The function of the circulatory system

The circulatory system has three major function: Transport

Moving things around the body in the blood stream such as oxygen and nutrients like glucose.

Body temperature control Thermoregulation, moving blood near the skin cools down the

body. That’s why you look redder when you exercise heavily.

Protection Moving anti-bodies around the body fighting diseases and clotting

cuts.

The structure of the heart

Oxygenated blood = more oxygen.

Found in arteries and arterioles

Normally red in colour

Deoxygenated blood = no oxygen

Found in the veins and venules

Normally blue in colour

The cardiovascular system: HEART

Structure of the Heart Surrounded by sac known as the pericardium,

which prevents friction as the heart beats. Heart wall is made of:

– Epicardium (outer layer)– Myocardium (strong middle layer)– Endocardium (inner layer)

Right separated from left by the Septum

Strokes of the heart

Heart rate = how many times your heart beats (normally in one minute, BPM)

Stroke volume = blood pumped per beat. Cardiac output = blood pumped per minute

– Cardiac output = Stroke volume x Heart rate

Task

Calculate a persons cardiac output when stroke volume = 10ml Heart rate = 78 BPM Cardiac output = ?

Circuits of the body

There are two circuits of the body you need to know:

Systemic Carries blood around the body via the transport system

supplying the major organs and muscles with blood.

Pulmonary Consists of the heart and lungs, deoxygenated from the

heart to the lungs to be oxygenated. The oxygenated blood then goes back to the heart to be pumped around the body.

Blood Flow Through the Heart

1. Vena Cava – Superior/Inferior

2. Right Atrium

3. Tricuspid Valve

4. Right ventricle

5. Pulmonary Artery

LUNGS

Blood Flow Through the Heart

6. Pulmonary veins

7. Left Atrium

8. Bicuspid/Mitral/Atrioventricular valve

9. Left Ventricle

10. Aorta

MAJOR ORGANS

Control of the Heart

Initial Stimulus originates in the Sinoatrial node (SA node)

Pacemaker determines heart rate Wave of excitation across both atria causes

them to contract

Control of the Heart

Sinoventricular node (SV node) Both atria and both ventricles contract at the

same time Systole-contraction of heart Diastole-Relaxation/filling of the heart

Blood vessels

There are three types of blood vessels you need to know:

Arteries Veins Capillaries

Types of Blood VesselsTypes of Blood Vessels

ArteryArtery

VenuoleVenuole

VeinVein

ArterioleArteriole

CapillaryCapillary

Arteries

Carry oxygenated blood away from the heart (the pulmonary artery brings blood to the heart!!)

They have thick strong elastic walls.

Small arteries are called arterioles.

Veins

Carry deoxygenated blood back to the heart (the pulmonary vein carries blood away from the heart!!).

The veins have thinner walls as the blood pressure is lower.

Veins have valves that keep blood flowing in the right direction.

Small veins are called venules.

Capillaries

Carry digested foods and oxygen directly to the tissue.

Take away waste products of the body.

Very small and vary in size.

How it works!!

Heart Arteries Arterioles Capillaries Gas exchange Venules Veins Heart

Blood flow through the heart

Warm-up questions

How many circuits are there in the circulatory system?

What type of blood is carried back to the heart? Which type of blood vessel carries blood away

from the heart? Which type of blood cell carries oxygen? Which type of blood cell fights diseases?

Changes in heart rate during exercise

There is a anticipatory rise due to hormonal action.

Then there is a sharp rise due to stimuli and hormonal response.

The heart rate steadies off during constant maximal exercise (heart rate max)

Changes in the respiratory

Tidal volume increases. Residual volume

increases. Breathing rate and the

volume of oxygen consumed is increased due to the onset of lactic acid.

Adaptations to the body over long periods of exercise.

Increase in the number of capillaries.

Increase in the efficiency of gaseous exchange.

Lower resting heart rate.