https://www.heart.org/en/health-topics/congenital-heart-defects/about-congenital-heart-defects/ventricular-septal-defect-vsd

Dean, l. (2005). Blood Transfusions and the immune system. Nih.gov; National Center for Biotechnology Information (US).

https://www.ncbi.nlm.nih.gov/books/NBK2265/

Frontiers in Cell and Developmental Biology. (2020). Mechanotranduction Pathways in the Regulation of Mitochondrial Homeostasis in Cardiomyocytes (X. Tang, Ed.) [Review of Mechanotranduction Pathways in the Regulation of Mitochondrial Homeostasis in Cardiomyocytes]. https://www.frontiersin.org/articles/10.3389/fcell.2020.625089/full

Healthdirect Australia. (2020, September 15). Heart failure. Www.healthdirect.gov.au. https://www.healthdirect.gov.au/heart-failure

Heart Foundation. (2023). What is angina | Heart Foundation. Heartfoundation-Prod.azurewebsites.net. https://www.heartfoundation.org.au/bundles/your-heart/angina

Heart Foundation. (n.d.). Coronary heart disease / Heart Foundation.

https://www.heartfoundation.org.au/bundles/your-heart/coronary-heart-disease

Heart Valve Diseases – Types / NHLBI, NIH. (2022, March 24). Nih.gov.

https://www.nhlbi.nih.gov/health/heart-valve-diseases/types

Mayo Clinic. (2018). Heart attack - Diagnosis and treatment - Mayo Clinic. Mayoclinic.org. https://www.mayoclinic.org/diseases-conditions/heart-attack/diagnosis-treatment/drc-20373112

Myocarditis Foundation. (2017). Understanding Myocarditis – Myocarditis Foundation. Myocarditis Foundation. https://www.myocarditisfoundation.org/about-myocarditis/

National Kidney Foundation. (2019, May 8). The Heart and Kidney Connection. National Kidney Foundation. https://www.kidney.org/atoz/content/heart-and-kidney-connection

NHS Choices. (2019). Treatment - Atrial fibrillation. NHS. https://www.nhs.uk/conditions/atrial-fibrillation/treatment/

Services, D.of H. & H. (n.d.) Heart murmur.

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Woodcock, E. A., & Matkovich, S. J. (2005). Cardiomyocytes structure, function and associated pathologies. The International Journal of Biochemistry & Cell Biology, 37(9), 1746–1751. https://doi.org/10.1016/j.biocel.2005.04.011

Right Atrium – receives deoxygenated blood from the body via the superior and inferior vena cava. It contracts pumping blood to right the right ventricle.

Right Ventricle – receives blood from the right atrium and pumps the blood to the pulmonary trunk to be oxygenated via the lungs.

Left Atrium – receives oxygenated blood from the lungs via the pulmonary vein and then pumps the blood to the left ventricle.

Left Ventricle – receives the oxygenated blood from the eft atrium and pumps it back into the body via the aorta.

 

both AV valves are located between the atriums and ventricles.

Bicuspid Valves

Tricuspid Valves

Structures of the Av valves:

-       Cusps

-       Papillary muscles

-       Chordae tendineae

 

SL valves

Aortic Valve – located between the left ventricle and aorta.

Pulmonary Valve – located between the right ventricle and pulmonary trunk.

Structures of SL valves:

-       Cusps reinforced by connective tissue.

Atrial Depolarisation – is the movement of an action potential through the atria.

Ventricle Depolarisation – the movement of an action potential through the ventricle.

Ventricle Repolarisation – recharging of ventricles after an action potential.

Atrial Repolarisation – occurs as the same time as ventricle depolarisation, therefore is hidden on the ECG under the QRS Complex.

Waves of an ECG:
P Wave = Atrial Depolarisation

QRS Complex = Ventricle Depolarisation

T Wave = Ventricle Repolarisation

SV is the volume of blood pumped from each ventricle during each contraction.

HR is the number of heart beats per minute.

It is important that we keep measure of cardiac output as if it is too low it means that the bodies vital organs aren’t receiving enough oxygen.

Type A – when you only have A antigen on the surface of your red blood cells.

Type B – when you only have B antigen on the surface of your red blood cells.

Type AB – when you have both A and B antigens on the surface of your red blood cells.

Type O – when you have neither A or B antigens on the surface of your red blood cells.

Tunica Media – this is the middle layer of the blood vessel it contains smooth muscle, and its function is to control the size of the lumen.

Tunica Externa – contains the vessels and nerves used to feed and stimulate the vessels. It also anchors the vessels to surrounding tissues.

   - arteries have thick, muscular walls, which allows them to endure the high pressure generated by the heart's pumping action.

   - The biggest and main artery in the body is the aorta, the aorta carries oxygenated blood from the left ventricle of the heart and transports it into smaller arteries across the body.

   - Arteries usually have a pulsatile flow of blood due to the rhythmic contractions of the heart, leading to a strong, sporadic surge of blood.

   - Arteries branch into smaller arterioles, which further branch into tiny capillaries to enable the exchange of oxygen, nutrients, and waste products.

   - veins have much thinner walls than arteries and have less muscular tissue because they operate at lower pressure.

   - Veins commonly appear bluish in color due to the deoxygenated blood they carry.

   - Valves are present in lots of veins, specifically in the limbs, to stop the backflow of blood and assist in the return of blood to the heart.

   - The largest veins in the body are the superior and inferior vena cava, which carry deoxygenated blood back to the right atrium of the heart.

   - Smaller veins join into larger ones, eventually leading to the vena cava.

   - They have extremely thin walls, consisting of a single layer of endothelial cells, this allows for the exchange of gases (oxygen and carbon dioxide), nutrients, and waste products between the blood and tissues.

   - Capillaries take the role of delivery of oxygen and nutrients to cells and the removal of metabolic waste products.

   - The extensive network of capillaries makes certain that nearly every cell in the body is near a capillary bed.

   - Blood flow in capillaries is quite slow, enabling efficient exchange.

1. Systolic Blood Pressure (SBP):

   - Systolic blood pressure is the top number in a blood pressure reading. It signifies the highest pressure within the arteries when the heart contracts and pumps blood into the arteries.

   - Systolic blood pressure is the result of the pressure during the heart's systole phase.

2. Diastolic Blood Pressure (DBP):

   -DBP is the bottom number in a blood pressure reading. It conveys the lowest pressure within the arteries when the heart is at rest between beats or in the diastole phase.

   - Diastolic blood pressure is the baseline pressure within the arteries.

A typical blood pressure reading is presented as systolic over diastolic, with normal values often reading as 120/80 mm Hg. In this example:

- Normal Blood Pressure: Generally considered to be around or below 120/80 mm Hg.

   - It indicates that blood pressure is within a healthy and normal range, and reduces the risk of cardiovascular problems.

It helps to redirect blood flow away from less critical areas and increase blood pressure, ensuring an adequate supply of oxygen and nutrients to vital organs and tissues during times of stress or need.

 Its role is to increase blood flow to specific areas, helping to transport more oxygen and nutrients to tissues and remove waste products.

Coronary heart disease needs to be diagnosed by a medical professional and can normally be managed by lifestyle changes and medications, however in more severe cases it may require surgery (Heart Foundation, n.d.).

When an infant is very ill a temporary operation known as Pulmonary artery banding can be done. This is when they narrow the pulmonary artery which results in reduced blood flow to the lungs. When the child Is older an operation will be performed to remove the banding an complete open heart surgery to correct the hole (American Heart Association, 2019)

There are two main types of atresia:

-       Pulmonary Atresia – this effects the pulmonary valve when you have this condition blood is unable to flow from the heart to the lungs via the pulmonary artery.

-       Tricuspid Atresia – this effects the tricuspid valve when you have this type of atresia blood is unable to flow from the right atrium to the right ventricle (Heart Valve Diseases – Types / NHLBI, NIH, 2022).

Vasoconstriction assists to minimise blood loss and allows time for the subsequent phases of hemostasis to occur. Things such as injury, pain, and reflexes can trigger a vascular spasm.

   - Platelets are small, cell-like fragments in the blood.

   - When a blood vessel is injured, the exposed collagen fibres in the vessel wall activate platelets to stick to the site of injury.

   - Once attached, platelets will release chemicals, including ADP and thromboxane, which further activate nearby platelets.

   - The activation leads to platelet aggregation, where platelets bind together to form a plug at the site of injury that temporarily plugs the damaged area.

   - The platelet plug is not stable or a permanent solution, but its purpose is to serve as an initial barrier to prevent excessive bleeding.

   
- coagulation results in the formation of fibrin clots, which strengthens the platelet plug to create a more steady barrier at the injury site.

   - The coagulation cascade involves several factors of clotting, including prothrombin, and fibrinogen.

   - The cascade ends in the conversion of soluble fibrinogen into insoluble strands of fibrin, which will form a mesh-like structure around the platelet plug.

   - Fibrin strands can trap blood cells; this creates a solid clot that aids in stopping bleeding.

   - The formation of the fibrin clot is tightly controlled to avoid excessive clotting (thrombosis) throughout the body.

Some of the Symptoms of a heart attack include chest pain, discomfort shortness of breath, nausea or vomiting, dizziness or lightheadedness, Indigestion, or heartburn.

Treatments for heart attack include medications such as Aspirin, aspirin helps decrease the clotting of blood and assist the blood flow through narrow arteries. (Mayo Clinic, 2018)

   - Hypertension is defined as constantly elevated blood pressure.

   - It is often categorised into two stages:
     - Stage 1 Hypertension: Systolic BP is 130-139 mm Hg, and/or diastolic BP is 80-89 mm Hg.

     - Stage 2 Hypertension: Systolic BP is 140 mm Hg or higher, and/or diastolic BP is 90 mm Hg or higher.

   - Hypertension is a common risk factor for strokes and heart disease.

Hypotension (Low Blood Pressure):

   - Hypotension is defined as blood pressure that is lower than normal.

   - symptoms linked with hypotension include dizziness, fainting, and fatigue.

Symptoms of heart failure may include shortness of breath, fatigue, swelling (edema) in the legs and ankles, and fluid retention. 

Treatments for heart failure include medications that lower the strain on the heart and lower blood pressure. Some medications include ACE inhibitors and angiotensin II receptor blockers (ARBs). (Healthdirect Australia, 2020)

Most heart murmur are mild and don’t require treatment however in more serious cases it can be controlled by antibiotics or surgery (Services, n.d.).

Symptoms can include:

Cyanosis

Chest pain

Heart palpitations

Breathlessness

Fatigue

Accelerated heart rate

   - Plasma is a straw-coloured fluid that appears translucent and yellow.

   - Plasma is mainly composed of water (around 90%), however, it contains multiple solutes, such as proteins, electrolytes (such as sodium, potassium, calcium, and chloride), waste products, gases, and hormones.

   - The three major proteins in plasma are fibrinogen, globulins (including antibodies), and albumin.

   - The various roles of plasma are that it helps maintain blood pressure, transport nutrients, hormones, and waste products and it plays a pivotal role in maintaining the blood's pH level.

   - They are specific cells that contain the protein hemoglobin, hemoglobin binds to oxygen and carbon dioxide throughout the body.

   - Red blood cells transport oxygen from the lungs to tissues throughout the body and carry carbon dioxide from tissues back to the lungs during exhalation.

   - Red blood cells have a biconcave shape of red blood cells which provides a larger surface area that creates efficient gas exchange.

   - There are various types of white blood cells including lymphocytes, neutrophils, eosinophils, monocytes, and basophils each has different and specific functions in immune response.

   - White blood cells can move out of the bloodstream to reach infected tissues and cells as well as engage pathogens.

   - Platelets are small, cell-like fragments of larger cells called megakaryocytes.

   - They play a pivotal role in blood clotting (hemostasis) by aggregating at the injury site to stop the bleeding.

   - Platelets release chemicals that help in the clotting process.