Cardiovascular System

Structure, Function & Response to Acute & Long Term Exercise

Cardiovascular System

- Referred to as the Circulatory System - Consist of Heart, Blood Vessels & Blood- Major transport system which carries food &

oxygen to body tissues- Carbon Dioxide is carried from cells to the

lungs

Basic Structure

Located on the left hand side of the chest beneath the sternum

Weighs approx. 255 grams and is the size of a closed fist

Basic function is a hollow muscular pump that drives blood into and through arteries in order to deliver to the workings muscles and tissues in the

body

Basic Structure - Heart is surrounded by a two layered sac known as the pericardium

- The cavity between the layers is filled with pericardial fluid, the purpose is to prevent friction when the heart beats

- The heart is made of three layers

Epicardium – Outer LayerMyocardium – Strong Middle Layer

Endocardium – Inner Layer

The septum is the wall that separates the left from the right. This prevents blood from the right coming into contact with the left

Pathway of Blood -The heart can be thought of as two pumps, the two chambers on the right and the left function separately

-The chambers on the right supply blood at a low pressure to the lings via the pulmonary arteries,

arterioles and capillaries where gaseous exchange takes place.

- Carbon dioxide passes through the blood to alveoli of the lungs and oxygen is taken on board. This blood is

then returned to the left side of the heart via the capillaries, venules and veins

Pathway of Blood - When the chambers of the left side are full it contracts

simultaneously with the right, acting as a high pressure pump

- This supplies oxygenated blood via the arteries, arterioles and capillaries to the tissues and muscle cells

- Oxygen passes from the blood to the cells and carbon dioxide (Waste Product) is taken on board

- Blood returns to the right atrium of the heart via the capillaries, venules and veins04152

Blood Vessels• As the heart contracts blood flows around the body

• Around 96,000km of arteries, arterioles, capillaries, venules and veins maintain circulation

• The function of each of these is determined by their structure and pressure of blood within them

• Blood flowing through the arteries appears bright red, due to oxygenation. As it moves through the network it drops of oxygen and picks up carbon dioxide, resulting in blood

appearing in veins as much bluer

Arteries

• Carry blood away from the heart, and other than the pulmonary artery carry oxygenated blood

• Thick muscle walls, and expand when blood is ejected into them

Arterioles

• Thinner walls than arteries• Control blood distribution

Capillaries

• Form and extensive network• Smallest of the vessels and are very thin

Veins

• Facilitate return of deoxygenated blood to the heart

• Branch into smaller vessels called venules

Venuoles

• Branches off the vein and are also linked to the capillaries

Definitions

Arteries carry oxygenated blood away from the heart

Veins carry deoxygenated blood back to the heart

Capillaries connect the veins and arteries

Left Atrium

Right Atrium

Right Ventricle

Left Ventricle

Bicuspid Valve

Tricuspid Valve

Aortic Valve

Pulmonary Valve

AortaSuperior

Vena Cava

Inferior Vena Cava

Pulmonary Veins

Pulmonary Artery

Atria

- Upper chambers of the heart

- Receive blood returning to your heart from either body or lungs

- Right Atrium receives deoxygenated blood from superior and inferior vena cava

- The left atrium receives oxygenated blood from the left and right pulmonary veins

Ventricles

- The pumping chambers of the heart

- Thicker walls than Atria

- Right ventricle pumps blood to the pulmonary circulation for the lungs

- Left ventricle pumps blood to the systemic circulation for the body

Bicuspid (Mitral) Valve

- One of the four valves in the heart between the left atrium and the left ventricle

- It allows blood to flow in one direction only, from the left atrium to the right ventricle

Tricuspid Valve

- Situated between the right atrium and the right ventricle

- Allows blood to flow from the right atrium to the right ventricle

Aortic Valve

- Situated between the left ventricle and the aorta

- Prevents backflow from the pulmonary aorta

Aorta

- The body's main artery

- It originates in the left ventricle and carries oxygenated blood to all parts of the body

except the lungs

Superior Vena Cava

- A vein that receives deoxygenated blood from the upper body to empty into the right atrium

of the heart

Inferior Vena Cava

- A vein that receives deoxygenated blood from the lower body to empty into the right atrium

of the heart

Pulmonary Vein

- Carries oxygenated blood from the lungs to the left atrium of the heart

Pulmonary Artery

- Carries deoxygenated blood from the heart back to the lungs

- it is the only artery that carries deoxygenated blood

Functions of The CV System

• Delivery of Oxygen & Nutrients• Removal of Waste Products• Thermoregulation• Vasodilatation & Vasoconstriction• Function of Blood• Oxygen Transport, Clotting & Fighting

Infection

Delivery of Oxygen & Nutrients

• A key function is to supply oxygen and nutrients to the tissues of the body via the

bloodstream

Removal of Waste Products

• As well as providing oxygen and nutrients to all tissues in the body, the circulatory system carries waste products from the tissues to the kidneys and the liver returns carbon dioxide

from the tissues to the lungs

Thermoregulation

Increased energy expenditure during exercise requires adjustments in blood flow that affect

the CV system

The CV system is responsible for the distribution and redistribution of heat with your body to maintain thermal balance during exercises

Vasodilatation

During exercise the vascular portion of active muscles increase through dilation of

arterioles. This is known as vasodilatation

Vasodilatation causes an increase in the diameter of blood vessels to decrease

resistance to the flow of blood to the area supplied by the vessels

Vasoconstriction• Vasoconstriction is the narrowing of the blood vessels

resulting from contraction of the muscular wall of the vessels, particularly the large arteries and small arterioles. The process is the opposite of vasodilatation, the widening

of blood vessels. The process is particularly important in staunching haemorrhage and acute blood loss. When blood

vessels constrict, the flow of blood is restricted or decreased, thus, retaining body heat or increasing vascular

resistance. As a result, this makes the skin turn paler because less blood reaches the surface, reducing the

radiation of heat. On a larger level, vasoconstriction is one mechanism by which the body regulates and maintains

mean arterial pressure

Function of Blood• Blood provides the fluid environment for cells and acts as transport

• Each person has approx 4 – 5 litres of blood

• Four principles components (Plasma/Red Blood Cells/White Blood Cells/Platelets)

• Has a function of distribution, regulation and protection

• Maintains body temperature

• Life sustaining nutrients are transported from the intestines, and waste products transported to the kidneys

• Hormones, medicines & antibodies including white blood cells are all transported by blood

Oxygen Transport

• As a result of exercise the demand for oxygen increases

• Blood transports oxygen from the lungs to the parts of the body that require it

Clotting

• Clotting is enabled by white blood cells forming solid clots

• A damaged blood vessel wall is covered by a clot to repair the damaged vessel

Fighting Infection

• Blood contains antibodies and white blood cells which help defend against viruses and

bacteria