BODY SYSTEMS 1 EXAM

Where is the heart located?

In the mediastinum, between the fifth rib and 2nd intercostal space.

What is the orientation of the heart?

The apex points inferiorly and to the left; the right heart is mainly at the anterior side.

What are the two main circulatory systems of the heart?

Pulmonary circulation (right side to lungs, lower pressure) and systemic circulation (left side to the rest of the body, high pressure).

What are the layers of the heart wall?

Endocardium (inner layer), myocardium (middle muscle layer), epicardium (outer layer).

What is the function of the pericardium?

It protects the heart and contains two layers: visceral (epicardium) and parietal.

What fills the pericardial cavity?

Serous fluid, which allows for frictionless movement of pericardial layers.

What are the subdivisions of the mediastinum?

Superior, anterior, middle (heart and great vessels), and posterior.

What is the role of the fibrous skeleton of the heart?

It keeps valve orifices patent, attaches valve leaflets, and electrically insulates atria from ventricles.

What is the function of heart valves?

They prevent backflow of blood during diastole and systole.

What are the characteristics of the right atrium?

Inflow from superior & inferior vena cava and coronary sinus; outflow to right ventricle via tricuspid valve.

What is unique about the left ventricle compared to the right ventricle?

It has thicker muscles to push blood further into the aorta.

What is the role of coronary arteries?

They supply blood to the heart muscles.

What is the significance of the sinoatrial node?

It is the pacemaker of the heart, generating action potentials.

What is the function of gap junctions in cardiac muscle?

They allow action potentials to propagate between myocardial cells.

What is the Frank-Starling law?

Increased cardiac filling leads to increased stroke volume due to better actin-myosin overlap.

What is the difference between stable and unstable plaques in atherosclerosis?

Stable plaques have a thick fibrous cap and are less likely to rupture; unstable plaques have a thin cap and are more prone to rupture.

What is the role of the autonomic nervous system in cardiac control?

Sympathetic stimulation increases heart rate and contractility; parasympathetic stimulation decreases heart rate.

What is the significance of the cardiac output?

It is the volume of blood pumped by one ventricle per minute, typically around 5L/min.

What is the role of baroreceptors?

They detect changes in arterial pressure and help regulate blood pressure.

What is the role of the renin-angiotensin system?

It regulates blood pressure and fluid balance by causing vasoconstriction and increasing blood volume.

What is the function of the atrial natriuretic factor?

It causes vasodilation and inhibits renin-angiotensin, decreasing blood pressure and volume.

What are the three layers of blood vessels?

Tunica interna (endothelium), tunica media (smooth muscle), and tunica externa (connective tissue).

What is the difference between arteries and veins?

Arteries have thicker walls and are more elastic; veins have larger lumens and valves to prevent backflow.

What is the role of pericytes?

They regulate blood flow and contribute to angiogenesis.

What is the significance of the cerebral arterial circle?

It provides collateral circulation to the brain in case of blockage.

What is the definition of hyperaemia?

An increase in blood flow to a tissue.

What is the primary cause of atherosclerosis?

Thickening and hardening of arteries due to fatty material buildup.

What are the consequences of myocardial infarction?

It can lead to tissue damage, chest pain, and potentially death.

What is the role of the vagus nerve in cardiac function?

It releases acetylcholine to decrease heart rate.

What does the ECG measure?

It measures heart rate, conduction, arrhythmias, and damage to the heart muscle.

What is the effect of sympathetic stimulation on cardiac output?

It increases cardiac contractility and heart rate.

What is the difference between intrinsic and extrinsic regulation of heart function?

Intrinsic regulation is based on venous return; extrinsic regulation involves autonomic nerves and hormones.

What is the significance of the cardiac function curve?

It illustrates the relationship between venous return and stroke volume.

What happens during isovolumic contraction?

All heart valves are closed, and pressure builds in the ventricles.

What is the role of the pulmonary trunk?

It carries deoxygenated blood from the right ventricle to the lungs.

What is the function of the aortic arch?

It distributes oxygenated blood from the left ventricle to the body.

What is the primary function of capillaries?

They facilitate the exchange of nutrients, gases, and waste between blood and tissues.

What is the role of the coronary sinus?

It collects deoxygenated blood from the heart muscle and drains into the right atrium.

What is the effect of calcium on cardiac muscle contraction?

Calcium influx triggers contraction through excitation-contraction coupling.

What is the role of the vagus nerve in controlling heart rate?

It decreases heart rate via parasympathetic stimulation.

What is the significance of the dicrotic notch?

It represents the rebound of blood against the closed aortic valve during diastole.

What is the primary determinant of mean arterial pressure?

Cardiac output and total peripheral resistance.

What happens during ventricular systole?

The ventricles contract, increasing pressure and ejecting blood into the aorta and pulmonary trunk.

What is the role of the sinoatrial node in the heart's conduction system?

It initiates the electrical impulses that trigger heartbeats.

What is the consequence of a complete heart block?

There is a dissociation between P waves and QRS complexes, leading to ineffective heart function.

What is the Circle of Willis associated with?

Stroke

What is Peripheral Vascular Disease characterized by?

Ulcers, gangrene, and occlusion of arteries.

What are the main arteries affected by Peripheral Vascular Disease?

Aortoiliac, femoral, tibial, peroneal, and popliteal arteries.

What is an aneurysm?

Localized abnormal dilation of a blood vessel.

What causes abdominal aortic aneurysms?

Weakening of the aortic wall due to inflammation.

What is systemic hypertension defined as?

A constant elevation of blood pressure (>140/90 mmHg).

What are non-modifiable risk factors for systemic hypertension?

Aging and family history.

What are some modifiable risk factors for systemic hypertension?

High fat and salt diet, diabetes, obesity, smoking, sedentary lifestyle, stress, and alcohol use.

What is primary essential hypertension?

Hypertension with an unknown cause (idiopathic).

What can cause secondary hypertension?

Renal disease, drugs, endocrine disorders, vascular issues, neurogenic causes, and pregnancy.

What is malignant hypertension?

A hypertensive emergency leading to organ damage.

What are the effects of hypertensive vascular disease on the kidneys?

Renal failure and hypertensive nephropathy.

What is the difference between a thrombus and an embolus?

A thrombus is an intravascular blood clot; an embolus is foreign material in the bloodstream causing blockage.

What is hyaline arteriolosclerosis?

Thickening of arterioles leading to narrowing of the lumen, often seen in benign hypertension and diabetes.

What is hyperplastic arteriolosclerosis?

Occurs in severe hypertension with concentric proliferation of smooth muscle cells.

What is ischaemic heart disease?

Decreased blood flow and oxygen to the heart muscle, often due to atherosclerosis.

What is angina pectoris?

Chest pain due to reduced blood flow to the heart.

What are the types of angina pectoris?

Stable, variant, and unstable angina.

What is a myocardial infarction?

Decreased or cessation of blood flow to the myocardium leading to tissue death.

What triggers a myocardial infarction?

Plaque disruption leading to blood clot formation.

What are the complications of myocardial infarction?

Cardiogenic shock, arrhythmias, mechanical complications, thromboembolic events, structural issues, and inflammatory responses.

What is sudden cardiac death?

Death occurring within 24 hours of the onset of disease, often due to arrhythmia.

What is pulmonary hypertension?

High blood pressure in the pulmonary artery forcing the right side of the heart to work harder.

What is cor pulmonale?

Right ventricle enlargement due to pulmonary hypertension.

What are the two types of hypertension?

Essential (primary) and secondary hypertension.

What is the definition of blood pressure?

The pressure of the blood on the walls of the blood vessels as the heart pumps blood.

What directly changes blood pressure?

Cardiac output.

What is peripheral vascular resistance?

Resistance in small blood vessels.

What is the role of antihypertensive drugs?

To reduce the risk of cardiovascular disease and stroke.

Name a class of antihypertensive drugs that modulates the sympathetic nervous system.

Alpha and beta adrenoceptor blockers.

What is the function of RAAS blockers?

To inhibit the Renin-Angiotensin Aldosterone System.

What is the main effect of calcium channel blockers?

Lowering cardiac output and blood pressure.

What is the primary active compound in nitrates?

Nitric oxide.

What is the effect of diuretics on blood pressure?

They increase the removal of water from the body, reducing plasma volume and lowering blood pressure.

What defines acute coronary syndrome?

Sudden reduction in blood supply to the heart due to blockage of the coronary arteries.

What therapeutic goals are aimed for in treating angina and heart attacks?

Improve myocardial perfusion, reduce metabolic need, and prevent clot formation.

What is the role of beta blockers in heart disease?

They reduce heart burden and oxygen consumption.

What is the conducting zone of the respiratory system?

The part that moves air to the site of gas exchange, filtering and warming the air.

What is the respiratory zone?

The site of gas exchange, consisting of bronchioles, alveolar sacs, and ducts.

What is the function of pleura in the respiratory system?

To reduce friction, create suction, and compartmentalize to prevent infection.

What is Boyle's Law in relation to pulmonary ventilation?

Pressure is inversely proportional to volume in a closed system.

What is tidal volume?

The amount of air inhaled or exhaled with each breath at rest.

What is the definition of dead space in the respiratory system?

Inspired air that never contributes to gas exchange.

What is compliance in the context of respiratory physiology?

Change in volume per change in pressure, indicating how easily the lungs can expand.

What is the difference between obstructive and restrictive lung disease?

Obstructive lung disease involves increased resistance from blocked airways, while restrictive lung disease involves reduced lung capacity.

What is the significance of FEV1 in pulmonary function tests?

It indicates the volume of air that can be forcibly exhaled in one second.

What is the role of bronchodilation?

Widening of the airway lumen, primarily mediated by B2 adrenergic receptors.

What is the effect of histamine on airway resistance?

It constricts bronchioles and alveolar ducts.

What is the function of the accessory muscles during forced breathing?

To increase chest volume during inspiration.

What is the relationship between airflow and airway resistance?

Airflow is inversely proportional to resistance.

What are the side effects of beta adrenoreceptor blockers?

Bronchoconstriction and peripheral vasoconstriction.

What is the mechanism of action for calcium antagonists?

They reduce the opening of L-type voltage-gated calcium channels.

What is the primary clinical use of nitrates?

To treat angina and heart failure.

What is the significance of residual volume in lung function?

It is the amount of air remaining in the lungs after forced exhalation.

What is the effect of chronic bronchitis on airway resistance?

It increases mucous production, leading to blocked bronchioles.