The Cardiovascular System

Anatomy of the Cardiovascular System

The cardiovascular system is sometimes called the circulatory system. It consists of the heart, which is a muscular pumping device, and a closed system of vessels called arteries, veins, and capillaries.

Blood contained in the circulatory system is pumped by the heart around a closed circle or circuit of vessels as it passes again and again through the various “circulations” of the body.

Physiology

The purpose of the cardiovascular system is to provide adequate circulation of blood through the body.

Pulmonary circulation allows for the oxygenation of the blood, and systemic circulation provides for oxygenated blood and nutrients to reach the rest of the body.

Common Conditions and Disorders:

  • Arrythmias

  • Stroke

  • Congestive Heart Failure

  • Congenital Heart Disease

  • Coronary Heart Disease

  • Atherosclerosis

  • Angina Pectoris

Atherosclerosis

  • Thickening and hardening of the arteries

  • Deposits of fatty substances, cholesterol, waste products, calcium, and clotting materials form plaque on the artery walls

Coronary Heart Disease

  • Heart Attack

    • A blockages of normal blood supply to an area of the heart that causes permanent damage

Angina Pectoris

Severe chest pain occurring as a result of reduced oxygen flow to the heart

Arrhythmias

  • An irregularity in the heart beat

    • Tachycardia

      • Racing heart in the absence of exercise or anxiety

    • Bradycardia

      • Abnormally slow heartbeat

Congestive Heart Failure

  • When the heart muscle is damaged or overworked and lacks the strength to keep blood circulating normally through the body

    • Rheumatic fever, pneumonia, heart attack, radiation, chemotherapy and many other conditions can damage the heart muscle

Congenital and Rheumatic Heart Disease

  • Congenital Heart Disease is a defect that is present at birth

  • Rheumatic Heart Disease is caused by an untreated strep infection (rheumatic fever) of the throat

Stroke

  • When the brain is damaged because the blood supply to the brain is interrupted

    • Thrombus (blood clot)

    • Embolus (a wandering clot)

    • Aneurysm (a weakened blood vessel that bulges and may burst)

  • Minor strokes may cause temporary dizziness or slight weakness or numbness

  • More serious strokes may cause speech impairments, memory problems, and loss of motor control

  • Some strokes that affect parts of the brain that regulate heart and lung function can kill a person in minutes

Reducing Cardiovascular Disease Risks

  • Avoid tobacco

  • Cut back on fats and cholesterol

  • Monitor your cholesterol levels

  • Reduce your intake of saturated fats

  • Lose weight

  • Increase the amount of fiber you eat

  • Exercise

  • Control your blood pressure

  • Manage stress

What is Blood Pressure?

Blood pressure is the pressure exerted on vessels walls and is expressed as two numbers

  • the higher number is the systolic BP, which is found when the heart is contracting

  • the lower number is diastolic BP, which is found when the heart relaxes

Hypertension (HTN)

Hypertension is having BP higher than 140/90

Hypertension is a risk factor for heart disease, stroke and kidney disease

Antihypertensives work to lower BP (blood pressure) by dilating blood vessels, slowing heart rate, and increasing elimination of fluids from the body. Often more than one drug will be needed

Beta Blockers

Beta blockers are medications that reduce blood pressure

Beta blockers work by blocking the effects of the neurotransmitter epinephrine, also known as adrenaline

BB may affect the heart or the heart and other parts of the body

The beta-1 receptors are found mainly in the heart and kidneys

The beta-2 receptors are found mainly in smooth muscle tissue (respiratory system)

The beta-3 receptors are found mainly in fat cells and in your bladder

Calcium Channel Blockers

Calcium channel blockers are medications used to lower blood pressure. They work by preventing calcium from entering the cells of the heart and arteries. By blocking calcium, calcium channel blockers allow the blood vessel walls to widen and relax and blood pressure is lowered.

These medications may also be prescribed to relieve chest pain (angina) and control an irregular heartbeat

ACE Inhibitors

Angiotensin-converting enzyme inhibitors (ACE inhibitors) are a class of medications that help lower your blood pressure and can protect your kidneys from damage caused by diabetes and HTN. They’re used to treat cardiovascular conditions like high blood pressure and heart failure.

Angiotensin II Receptor Blockers (A2RBS)

Similar to the work that ACE inhibitors do, angiotensin Ii receptor blockers help relax your veins and arteries to lower your blood pressure and make it easier for your heart to pump blood. They can also be used for heart failure and kidney disease.

Unlike ACE inhibitors, A2RBS reduce the action of angiotensin II to prevent blood vessel constriction whereas ACE inhibitors lower blood pressure by preventing the production of angiotensin II.

Alpha Adrenergic Blockers

Alpha adrenergic blockers lower blood pressure by preventing a hormone called norepinephrine from tightening the muscles in the walls of smaller arteries and veins. As a result, the blood vessels remain open and relaxed,. This improves blood flow and lowers blood pressure.

Because alpha adrenergic blockers also relax other muscles throughout the body they are sometimes used to improve urine flow in older men with prostate difficulties (BPH)

Diuretics

Diuretics are used to treat edema (swelling due to fluid buildup). Most of these medicines help your kidneys remove salt and water through the urine. This lowers the amount of fluid flowing through your veins and arteries. As a result, blood pressure goes down.

There are three types diuretics:

  • Thiazide

  • Loop

  • Potassium sparing

Each type of diuretic affects a different part of your kidneys. Some pills combine more than one type of diuretic or combine a diuretic with another blood pressure medication

Diuretics should always be taken in the morning; a patient should expect increase in urinary frequency and volume

Antihyperlipidemic (Used to lower cholesterol)

  • Drugs that treat hyperlipidemia, a condition marked by elevated cholesterol, phospholipids, and/or triglycerides in the blood

Cholesterol: The waxy substance made in the body derived from lipids (molecules that make up the building blocks of the structure and function of living cells) present in the body and essential for healthy cell function

  • Proteins and carbohydrates, as well as fat, are responsible for natural cholesterol production

  • Excess cholesterol causes fatty deposits and plaque to develop in the blood vessels, which cause the artery to become narrowed and blocked. This impairs the flow of blood to the body and if plaque ruptures from the arterial wall it can form into a clot.

Lipoproteins are groups of proteins carrying fats in the blood

  • Cholesterol levels are measured as total cholesterol, LDL (low-density lipoprotein) and HDL (high-density lipoprotein)

  • LDL is considered the “bad cholesterol” and will build upon on the arterial walls, causing them to harden and narrow therefore blocking the blood vessels and leads to other cardiovascular problems

  • HDL is considered the “good cholesterol” and its job is to pick up cholesterol in the body (break up blockages in the blood vessels) and deliver it to the liver

  • Hypercholesterolemia is high cholesterol and can cause the narrowing of the blood vessels due to plaque formation that may result in heart attacks and/or strokes

Blood Clot Risk Factors Thrombus

  • Smoking

  • Overweight and obesity

  • Pregnancy

  • Prolonged bed rest due to surgery, hospitalization or illness

  • Long periods of sitting such as car or plane trips

  • Use of birth control pills or hormone replacement therapy

  • Cancer

2 Classes that Decrease Risk of Blood Clots

  1. Anticoagulant: Prevents clot formation by inhibiting clotting factors; may prevent existing clots from expanding; often used to treat DVT, pulmonary embolism and acute cardio embolus stroke (stroke resulting from the heart circulating an embolism)

  2. Antiplatelet: Reduce risk of clot formation by inhibiting platelet aggregation (sticking or clumping together of platelets); used to prevent recurrent thrombotic strokes and in high risk patients for stroke

Anticoagulants

  • Blood thinner

  • Treatment and prevention of blood clots

    • Deep vein thrombosis (DVT)

    • Stroke

    • Pulmonary embolism (PE)

Anticoagulant Agents

  • Heparin

  • Low-molecular weight heparin

  • Warfarin

  • Oral Active Direct Factor Xa inhibitor

  • Antiplatelets

Antiarrhythmic

Arrhythmias occur when the heart beats with an irregular rhythm. Also known as dysrhythmias

Two types:

Tachycardia = rapid > 100 beats/min

Bradycardia = slow < 60 beats/min

Symptoms: Fluttering in the chest, rapid or slow heartbeat, chest pain, SOB, lightheadedness, sweating