Cardiovascular system

what is the role of the cardiovascular system

to transport oxygen, nutrients, hormones and cellular waste around the body via the blood.

what does the cardiovascular system transport

O2 & essential nutrients (i.e. hormones) to the body's tissues & removal of wastes (i.e. CO2)

What does the cardiovascular system protect?

Through the production of white blood cells (i.e. immune cells), to fight pathogens & clean up debris. Platelets & red blood cells form 'scabs', to seal wounds.

What does the cardiovascular system regulate?

Supports maintenance f a stable internal environment (i.e. 'homeostasis'), such as temperature, when blood vessels dilate, constrict or blood flow is redirected to vital organs.

Function of the blood

to transport O2, nutrients, wastes and hormones around the body, and aid in temperature regulation.

What are Erythrocytes

red blood cells

What is the primary function of red blood cells?

Transport O2 around the body.

What protein do red blood cells contain that binds O2?

Haemoglobin

What shape are red blood cells?

Concave

What do red blood cells transport from the cells to the lungs?

CO2

What are luekocytes?

white blood cells

White blood cells

•play a variety of roles in the body's immune system & fighting off pathogens (bacteria, fungi, parasites, viruses etc.). Examples:

oNeutrophils

oDendritic Cells

T cells + B cells

Platelets (Thrombocytes)

play a major role in blood clotting. They are cell fragments that quickly seal themselves off from surrounding fluids; thus creating a blood clot to stop excess bleeding.

Plasma

the liquid component of blood; pale / yellow fluid that contains nutrients, salts, gasses and hormones. Assists in maintaining of normal blood pressure and the exchange of materials.

Arteries

blood vessels that carry oxygenated blood from the heart to the rest of the body

artery structure

•Walls of arteries are thicker & more elastics that other types of blood vessels - this is to support the high volume of blood that needs to be transported at high pressure.

•Do not have 'valves' to prevent the back flow of blood.

Aorta

the main artery that carries oxygenated blood from the heart to organs, cells & tissues

Femoral Artery

provides oxygenated blood to the lower limbs

Subclavian Artery

provides oxygenated blood to the upper limbs

Vein

blood vessels that carry de-oxygenated blood to the heart to the rest of the body

Vein Structure

•Walls of arteries are much thinner than arteries, and the pressure is far less.

•Veins have valves that prevent the backflow of blood, whereas arteries do not.

Femoral Vein

transports deoxygenated blood from the lower half of the body back to heart to become oxygenated

Vena Cava

2 x major veins entering the heart

Capillary

blood vessels that allow for blood to be transported from/between arteries and veins

Capillary Structure

•Very small in size - allowing for blood to reach many parts of a single muscle, organ or tissue.

•Participate in gas exchange - O2 is provided to cells & exchanged for CO2 (waste product)

•They connect the tiny muscular branches of arteries, called arterioles, with tiny veins called venules.

E.g. A single capillary is only one cell thick, and is surrounded by only a thin layer of epithelium.

Heart Function

to undertake muscular contractions to pump blood around the body to required cells / tissues.

Location of the heart

Medial to the lungs, deep in the thoracic cavity (in it's own 'pericardial' cavity)

function of the right side of the heart?

The right side of the heart receives oxygen-poor (deoxygenated) blood, sending it to the lungs, to become oxygenated.

Function of the left side of the heart

The left side handles oxygen-rich (oxygenated) blood from the lungs, distributing it to the rest of the body

Septum

a muscular wall that separates the left and right sides of the heart, preventing oxygen-rich and oxygen-poor blood from mixing

Right Atrium

receives oxygen-poor blood returning from the body.

Right Ventricle

pumps oxygen-poor blood to the lungs for oxygenation

left atrium

receives oxygen-rich blood coming back from the lungs.

left ventricle

pumps oxygen-rich blood to the rest of the body at high pressure.

aorta function

The largest blood vessel (artery) in the body - carries oxygen-rich blood from the left ventricle to the body

tricuspid valve

Helps blood flow in the correct direction from the right atrium to the right ventricle

Mitral (Bicuspid) Valve

Helps blood flow in the correct direction from the left atrium to the left ventricle

Aortic valve

Helps blood flow in the correct direction from the left ventricle through the aorta, to be distributed to the rest of the body

Pulmonary valve

Helps blood flow in the correct direction from the right ventricle through the pulmonary artery, to be distributed to the lungs to become oxygenated

Vena Cava function

returns oxygen-poor blood from the body to the right atrium:

-Superior Vena Cava: collects blood from the head, neck, arms, and chest

-Inferior Vena Cava: collects blood from the lower limbs, pelvis, and abdomen

pulmonary Artery

Carries oxygen - poor blood from the right ventricle to the lungs, to become oxygenated

Pulmonary Vein

Carries oxygenated blood from the lungs to the left atrium, to be sent out to the body once again

Pathway of the Blood

(1)Deoxygenated blood from the body returns and enters the heart via the superior + inferior vena cava

(2)The blood then enters via the right atrium, where it is pumped through the tricuspid valve, to the right ventricle.

(3)The deoxygenated blood travels through the pulmonary valve, through to the pulmonary arteries. This deoxygenated blood enters the lungs, where it participates in gas exchange (O2 enters the blood + CO2 exits). The blood is now oxygenated.

(4)Oxygenated blood arrives back to the heart through the pulmonary vein, where it enters the left atrium. Blood is pumped through the mitral (bicuspid) valve, to the left ventricle.

(5)Blood is pumped through the aortic valve to the aorta, where it will be distributed to the rest of the body

Systole (contraction phase)

at the end of the diastole, the atria contract and pump blood through to the ventricles (atria systole). The atria then relax. Now, the ventricles contract (ventricular systole), pumping blood out of the heart.

diastole (relaxation phase)

the atria and ventricles of your heart relax, and begin to fill with blood.

What is the ideal blood pressure?

•120 = Systolic Blood Pressure (pressure exerted when blood is ejected into the arteries)

•80 = Diastolic Blood Pressure (pressure blood exerts within the arteries between heartbeats)

or 120/80

Cardiac cycle

Cardiac diastole: All chambers relax and fill with blood

Atrial systole, ventricle diastole: Atria contract pushing blood into ventricles.

Atria diastole, Ventricle systole: After the atria relax, the ventricles contract pushing blood out of the heart

Heart beat

The heartbeat is controlled by highly - coordinated electrical signals produced by specialized cardiac muscle tissue cells.

How does the heart beat start?

Sinoatrial node (SA)

What is the sinoatrial node?

the heart's natural 'pace maker'. The SA Node sets the heart rate by producing electrical signals. These electrical signals spread across the right & left atria, causing them to contract (atria systole)

where does the signal reach from the sinoatrial node

atrioventricular node (AV)

What does the atrioventricular node (AV) do?

The signal then reaches the atrioventricular node (AV) - causing the ventricles to fill with blood before contracting (ventricular systole). The left ventricle fills with blood slightly before the right ventricle. The blood is then pumped to the lungs via the pulmonary arteries, and to the body through the aorta.

Atrial Fibrillation

Occurs when the heart's upper chambers (atria) receive chaotic electrical signals, causing them to quiver or twitch instead of beating properly.

What can cause Atrial fibrillation?

•High blood pressure - through extra strain being put on the cardiac muscles

•Sleep apnoea - poor sleep quality + breathing interruptions strain the cardiovascular system over time

•Lifestyle factors - excessive alcohol consumption, smoking etc.

heart rate/pulse

the number of signals the SA node produces per minute

Average adult resting HR

60-100bpm

How to find max HR

220 - your age

Systemic Circuit

provides oxygen rich blood to the body, by pumping blood from the heart to the organs / cells. The blood returns through systemic veins with CO2.

Pulmonary circuit

responsible for re-oxygenating oxygen deficient blood after it has returned to the heart through the systemic circuit. The pulmonary arteries carry low - O2 blood to the lungs for gas exchange. The pulmonary veins then return this oxygen rich blood back to the heart, to be pumped through the systemic circulation pathway once again.

What is Coronary heart disease

results from narrowed / hardened coronary arteries (the ones that supply the heart with it's own O2), as a result of the buildup of cholesterol / plaques ('atherosclerosis'). This reduced blood flow, with the heart not being able to receive sufficient blood or O2. Can lead to chest pain ('angina') and cause a heart attack.

What is High Blood Pressure (Hypertension)

categorised by BP > 140 / 90. If this is left untreated, it dramatically affects blood flow to major organs, and is directly linked with increased chances of stroke, kidney failure or diabetes.

What is Congestive Heart Failure

categorised by a weakened pumping power than normal. Results from blood being unable to pump through the chambers effectively; compounded with higher blood pressure. As compensation, the heart responds by 'stretching' to store more blood, but over time, these muscular walls weaken. The kidney's then signal to 'store more fluids', which can build up in the arms, legs, feet or lungs.