Human Gas Exchange and Respiratory System

Vocabulary flashcards covering the anatomy, mechanics, and chemistry of the human respiratory system based on the lecture transcript.

Bicarbonate ion ($HCO_3^-$)

The main buffer molecule in the blood and the form in which most $CO_2$ is transported in plasma.

Carbonic anhydrase

The enzyme that catalyzes the conversion of $CO_2$ into $HCO_3^-$ via the reaction: $CO_2 + H_2O \rightleftharpoons H_2CO_3 \rightleftharpoons H^+ + HCO_3^-$.

Pharynx

The throat; a passage for both food and air where dust and mucus are swept back by cilia.

Larynx

The voice box; contains a cough reflex that activates if non-gas material enters the structure.

Trachea

The windpipe which contains C-shaped ringed cartilage covered by cilia and mucus cells; it is covered by the epiglottis during swallowing.

Alveoli

Small sacs at the end of bronchioles surrounded by blood-carrying capillaries where gas exchange occurs via diffusion.

Surfactant

A coating on the alveoli that reduces surface tension.

Inhalation

The process where the diaphragm moves down (contracts), lung volume increases, pressure inside the lungs decreases, and air flows in.

Exhalation

The process where the diaphragm rises (relaxes), lung volume decreases, pressure inside the lungs increases, and air rushes out.

Hemoglobin

A protein structure with 4 polypeptide subunits complexed around an $Fe$ atom, similar to chlorophyll which uses $Mg$.

Left Lung

The smaller of the two lungs, consisting of 2 lobes.

Right Lung

The larger of the two lungs, consisting of 3 lobes.

Visceral pleura

The membranous layer that lines the surface of the lungs.

Parietal pleura

The membranous layer that lines the inside of the chest cavity.

Goblet cells

Respiratory epithelium cells that function to secrete mucus.

Basal cells

Respiratory epithelium cells that produce new cells.

Cilia cells

Respiratory epithelium cells that sweep debris trapped by mucus.

Medulla oblongata

The respiratory control center of the brain that stimulates ventilation rate in response to high partial pressure of $CO_2$.

Central chemoreceptors

Receptors located in the medulla that indirectly monitor $[H^+]$ in the cerebrospinal fluid.

Peripheral chemoreceptors

Receptors located in the carotid arteries and aorta that monitor atrial concentrations of $CO_2$, $O_2$, and $pH$ via $H^+$.

CADET, face right!

Mnemonic used to remember the factors that shift the oxygen dissociation curve to the right: $CO_2$, Acid, 2,3-DPG, Exercise, and Temperature.

Left shift (Oxygen Dissociation Curve)

A physiological state where oxygen is held more tightly by hemoglobin; occurs when right-shift factors are reversed.

Countercurrent exchange

An efficient respiration mechanism in fish where water outside and blood inside flow past each other in opposite directions to maximize the diffusion of $O_2$ into the blood.