all midterm notes

Flashcards covering key vocabulary related to the respiratory and circulatory systems, including gas exchange, blood transport, heart anatomy, and blood vessels.

Respiratory System

The system responsible for delivering oxygen to body tissues and removing carbon dioxide.

Diffusion (Gas Exchange)

A slow, passive transport process sufficient for gas exchange in unicellular and small multicellular organisms where oxygen uptake matches diffusion rate.

Direct Diffusion

Gas exchange across surface membranes, efficient for organisms less than 1 mm in diameter like cnidarians and flatworms.

Gills

Thin, highly branched and folded tissue filaments found in aquatic organisms (e.g., fish, mollusks) for extracting dissolved oxygen from water.

Tracheal System

A highly specialized network of small tubes made of chitin in insects that carries oxygen directly to the entire body, independent of the circulatory system.

Spiracles

Openings along the thorax and abdomen of insects that connect to the tracheal system, allowing oxygen to pass into the body.

Nasal Cavity

The entry point for air in mammals, where air is warmed, humidified, and particulate matter is removed by mucus and cilia.

Trachea

The windpipe, a cylinder composed of incomplete rings of hyaline cartilage and smooth muscle, lined with mucus-producing goblet cells and ciliated epithelia, funneling air to the lungs.

Cilia

Small hair-like projections lining the respiratory tract (e.g., trachea, bronchi) that beat in unison to propel foreign particles trapped in mucus towards the pharynx.

Bronchi

Passages into which the trachea bifurcates, leading to the right and left lungs, and further dividing into secondary and tertiary bronchi.

Bronchioles

Smaller passages branching from bronchi, where cartilage is replaced with elastic fibers, leading to alveolar ducts.

Alveoli (singular: alveolus)

Tiny, thin-walled parenchymal cells within alveolar sacs that are in direct contact with capillaries, serving as the primary site of gas exchange in the lungs.

Hemoglobin (Hb)

A protein molecule in red blood cells made of four subunits, each containing an iron-bound heme group, capable of binding four oxygen molecules for transport.

Oxygen Dissociation Curve

A sigmoidal-shaped graph plotting hemoglobin-oxygen saturation against the partial pressure of oxygen in the blood, illustrating hemoglobin's affinity for oxygen.

Carbaminohemoglobin

A molecule formed when carbon dioxide binds to hemoglobin, transporting about 10% of carbon dioxide in the blood.

Bicarbonate Buffer System

A primary mechanism for carbon dioxide transport (85%), where CO2 is converted to carbonic acid and then bicarbonate ions within red blood cells, regulating blood pH.

Carbonic Anhydrase (CA)

An enzyme within red blood cells that rapidly converts carbon dioxide and water into carbonic acid.

Chloride Shift

The transport of bicarbonate ions out of the red blood cell into the plasma in exchange for a chloride ion, maintaining charge balance during CO2 transport.

Carbon Monoxide Poisoning

A condition where carbon monoxide, due to its greater affinity for hemoglobin than oxygen, binds preferentially to Hb, impairing oxygen transport and causing oxygen deprivation.

Pulmonary Circuit

The division of the circulatory system that pumps deoxygenated blood from the heart to the lungs for re-oxygenation and returns oxygenated blood to the heart.

Systemic Circuit

The division of the circulatory system that pumps oxygenated blood from the heart to the rest of the body's organs and tissues, and returns deoxygenated blood to the heart.

Atria (singular: atrium)

The upper chambers of the heart that receive blood from the body (right atrium) or lungs (left atrium).

Ventricles

The lower chambers of the heart that pump blood out to the lungs (right ventricle) or the rest of the body (left ventricle).

Tricuspid Valve

The atrioventricular valve located between the right atrium and the right ventricle, preventing backflow of blood.

Mitral Valve (Bicuspid Valve)

The atrioventricular valve located between the left atrium and the left ventricle, preventing backflow of blood.

Aorta

The major artery of the body that receives oxygenated blood from the left ventricle and distributes it to the systemic circuit.

Myocardium

The thick middle layer of the heart wall, composed of cardiac muscle cells, responsible for the heart's pumping action.

Coronary Arteries

Arteries that branch from the aorta and supply the heart muscle itself with oxygenated blood.

Myocardial Infarction

The death of cardiac muscle tissue, commonly known as a heart attack, caused by a complete blockage of coronary arteries.

Cardiac Cycle

The repeating sequence of blood filling and emptying in the heart, driven by electrical signals causing muscle contraction (systole) and relaxation (diastole).

Systole

The contraction phase of the cardiac cycle, during which the heart pushes blood out to the body or lungs.

Diastole

The relaxation phase of the cardiac cycle, during which the heart chambers fill with blood.

Sinoatrial (SA) Node

The heart's internal pacemaker, located in the right atrium, that spontaneously generates electrical pulses initiating atrial contraction.

Electrocardiogram (ECG)

A recording of the electrical impulses generated by the cardiac muscle, measurable on the skin, used to assess heart function.

Arteries

Blood vessels that carry blood away from the heart to various body parts.

Capillaries

Narrow-diameter blood vessels with single-cell thick walls, forming capillary beds, where the exchange of nutrients, waste, and oxygen occurs at the cellular level.

Veins

Blood vessels that carry deoxygenated blood back to the heart, featuring valves to prevent backflow.

Tunica Intima (Endothelium)

The smooth, inner lining of endothelial cells that forms the innermost layer of blood vessels and is the site of diffusion in capillaries.

Tunica Media

The middle layer of blood vessel walls, composed of smooth muscle, which regulates blood flow through vasoconstriction and vasodilation.

Vasoconstriction

The narrowing of blood vessels, regulated by the smooth muscle in the tunica media.

Vasodilation

The widening of blood vessels, regulated by the smooth muscle in the tunica media.