Cardiovascular Health Quiz

Circulation - The Heart and Blood Vessels

• Arteries carry blood away from the heart.
• Veins carry blood towards the heart.
• Capillaries are where most exchange of materials takes place.
• Pulmonary circulation occurs between the heart and lungs.
• Systemic circulation occurs between the heart and the rest of the body.
• Coronary arteries supply the heart muscles with blood.
• Cardiac veins return blood from the heart muscles.

Blood Flow Through Blood Vessels

• Blood flows from the heart to the aorta.
• Aorta branches to arteries.
• Arteries branch to arterioles.
• Arterioles branch to capillaries.
• Capillaries branch to venules.
• Venules branch to veins.
• Veins return blood to the heart.
• Pulmonary arteries carry deoxygenated blood to the lungs.
• Pulmonary veins carry oxygenated blood back to the heart.
• Red represents oxygenated blood.
• Blue represents deoxygenated blood.

Specific Blood Vessels (Systemic Circulation)

• Arteries have thick walls due to high blood pressure.
• Elastic recoil helps move blood forward.
• Arterioles are small arteries that regulate blood flow to capillaries.
• Capillaries have a single layer of endothelium for easy exchange.
• Venules are small veins.
• Veins have thinner walls due to low blood pressure and store lots of blood.
• Veins have one-way valves to prevent backflow.

Blood Vessels: Arteries

• Endothelium: smooth epithelial cells reducing friction.
• Middle layer: smooth muscle for vasoconstriction/vasodilation; elastin for stretching/recoil.
• Outer layer: Connective tissue (collagen) anchors and protects.
• High blood pressure necessitates thick walls.

Blood Vessels: Arterioles

• Small arteries with smooth muscle and endothelium layers.
• Smooth muscle constricts (vasoconstriction) or widens (vasodilation) to regulate capillary blood flow.
• Pre-capillary sphincters control blood flow into capillaries.

Blood Vessels: Capillaries

• Almost all material exchange occurs between blood vessels and tissue.
• Only a single layer of squamous (flat) epithelial cells (endothelium) makes exchange easier.
• Gaps and pores facilitate nutrient, gas, waste, hormone, and white blood cell exchange.
• Large components (RBCs, platelets, albumin) remain in capillaries.
• Capillaries supply cells with materials and remove waste.

Capillary Structure

• Capillary walls consist of a single layer of endothelial cells.
• Pores and slits between cells facilitate exchange.

Capillaries (detailed)

• Blood pressure forces plasma out of capillaries.
• Proteins and red blood cells remain in capillaries.
• Fluid reenters capillaries via osmosis due to osmotic pressure.
• Albumin is important for water reuptake.

Edema in Starving Children

• Less albumin leads to water remaining in tissues.

Lymphatic System and Excess Fluid

• Not all fluid is reabsorbed by osmosis. The lymphatic system returns excess fluid to veins near the heart.

Blood Vessels: Venules/Veins

• Have connective tissue outer layer, smooth muscle middle layer, and endothelial inner layer.
• Carry blood towards the heart.
• Some exchange occurs at venules.
• Veins store 50-60% of blood due to wide lumen interiors.
• Thinner walls compared to arteries are sufficient for low blood pressure.
• One-way valves ensure unidirectional blood flow.

Blood Vessels: Venules/Veins (Mechanisms in Blood Return)

• Gravity assists blood return.
• Muscle contraction increases blood flow.
• Smooth muscle in veins contracts.
• One-way valves aid in blood movement.
• Breathing creates pressure differences. Inhaling lowers pressure in the thorax, causing blood to move towards the heart.

The Heart (what is the path of blood?)

• The heart has four chambers: two atria and two ventricles.
• The left ventricle is very muscular to pump blood to the whole body.
• The heart has two atrioventricular (AV) valves and two semilunar valves.
• The heart valves ensure one-way blood flow.

The Heart (structure)

• Four chambers in total.
• Two atria and two ventricles.
• Left ventricle is very muscular for pumping blood throughout the body.
• Two atrioventricular (AV) valves, two semilunar valves
• Connective tissue prevents valve flaps from opening in the wrong direction to ensure one-way blood flow.

Cardiac Cycle

• Ventricular systole: simultaneous contraction of both ventricles, closing AV valves and opening semilunar valves, blood pumped into arteries.
• Atrial systole: contraction of atria, forcing blood into ventricles, opening AV valves, closing semilunar valves.
• Valves prevent backflow.
• Blood flow follows pressure gradients.

Cardiac Cycle (cont.)

• "Lub-DUB" sounds are caused by valve closure.
• Lub: AV valve closure; DUB: semilunar valve closure.

Heart Sounds and Heart Valves

• Heart sounds (lub-dub) originate from valve closures.
• Murmurs indicate backflow through valves.

Heart Muscle Contractions

• Sinoatrial (SA) node: cardiac pacemaker that generates electrical signals initiating contraction.
• Gap junctions allow electrical impulses to spread rapidly across cardiac cells, causing synchronized contractions.
• Atrioventricular (AV) node receives impulse.
• AV bundle/Purkinje fibers transmit impulse to the ventricles.

Controlling The Heart Rate

• The heart can beat by itself at approximately 100 beats per minute.
• The medulla (part of the brain) regulates the sinoatrial node to slow the heart rate at rest.
• Stress and exercise stimulate faster heart rates.

Maintaining Homeostasis of Blood Pressure

• Baroreceptors in the aorta and carotid arteries monitor blood pressure.
• Medulla oblongata adjusts heart rate and arteriole width.

Blood Pressure

• Systolic pressure is the higher pressure during ventricular contraction.
• Diastolic pressure is the lower pressure during ventricular relaxation.
• Blood pressure is measured by a sphygmomanometer.

Cardiovascular Disorders: High Blood Pressure

• Hypertension is high blood pressure (>140/90).
• Concerning levels are above 120/80.
• High pressure causes stiff, scarred arteries and resistance to blood flow.
• Arteries' inner walls can have cholesterol plaques (atherosclerosis).

Cardiovascular Disorders: High Blood Pressure (cont)

• It's considered 'the silent killer', often having no obvious symptoms until complications arise.
• The consequences of high blood pressure can include: arteriosclerosis, embolism, heart attack, stroke, aneurysms, kidney damage.

Cardiovascular Disorders: Atherosclerosis

• Cholesterol plaques narrow arteries, limiting blood flow.

Cardiovascular Disorders: Embolism

• Blood clots or other matter breaking off and blocking blood flow.
• Can occur in vessels supplying the heart (heart attack) or brain (stroke).
• Emboli can be formed from tissues, cancer cells, cholesterol, bacteria, or air.

Cardiovascular Disorders: Angina Pectoris

• Chest pains and tightness indicating limited heart muscle blood flow.
• Often a warning of potential heart attacks.

Cardiovascular Disorders: Heart Attack

• Blocked coronary artery leads to oxygen deprivation in heart muscles (cardiac tissue death).
• Characterized by intense chest pain, arm pain, jaw pain possibly nausea and sweating.
• Prompt medical attention is crucial.

Cardiovascular Disorders: Ventricle Fibrillation

• Irregular heartbeats due to the sinoatrial node losing control.
• Causes disorganized, "quivering" contractions and can lead to sudden unconsciousness.
• Defibrillation and CPR can save lives until professional help arrives.

Preventing More Heart Attacks

• Medications can control blood pressure and cholesterol levels.
• Procedures such as bypass surgery and angioplasty can restore blood flow.

Cardiovascular Disorders: Stroke

• Lack of blood flow to parts of the brain (embolism, blood vessel rupture).
• High blood pressure and atherosclerosis are risks.
• Consequences and recovery vary depending on the affected brain area.

Cardiovascular Disorders: Aneurysm

• Weakening and ballooning of arterial walls.
• High blood pressure and atherosclerosis are risk factors.
• Can lead to death due to massive internal bleeding.

Reducing Risk of Cardiovascular Disease

• Avoid smoking and alcohol.
• Maintain healthy weight through exercise.
• Manage stress levels.
• Moderate salt intake and limit saturated fat.
• Increase soluble fiber.
• Eat fish oil.
• Control diabetes.
• Monitor blood pressure.

Benefits of Exercise to Your Heart

• Reduced blood pressure.
• Lower stress levels.
• Less cholesterol in blood.
• More red blood cells.
• Improved blood circulation.
• Stronger heart, reduced heart rate over time.

Test your knowledge on lifestyle changes and dietary modifications that can reduce the risk of cardiovascular disease. This quiz covers topics such as exercise benefits, the role of sugar, and functions within the circulatory system. Answer questions to evaluate your understanding of heart health!