Human Digestion and Respiration Review

Practice vocabulary flashcards covering the physiological processes of the digestive and respiratory systems as presented in the lecture notes.

Small Intestine

The organ responsible for the digestion of all nutrients and the absorption of the end products of digestion.

Large Intestine (Colon)

The segment of the digestive tract responsible for the final reabsorption of water, compaction of solid waste, and housing large populations of bacteria.

Microbiome (Coliforms)

Large populations of mostly gram-negative bacteria living in the large intestine that metabolize undigested fibers and produce vitamins like vitamin $K$ that are absorbed through the colon wall.

Respiratory Minute Volume

The total volume of air moving in and out of the lungs in one minute, calculated as the product of tidal volume and respiratory rate ($Tidal Volume \times Respiratory Rate$).

Anatomic Dead Space

The volume of inhaled air trapped in the airways (bronchioles and trachea) that is not exchanged, typically accounting for about one-third of the tidal volume.

Alveolar Ventilation

The volume of air that reaches the alveoli to oxygenate the blood, calculated as $Respiratory Rate \times (Tidal Volume - Anatomic Dead Space)$. house.

Vital Capacity

The sum of the inspiratory reserve volume ($IRV$), tidal volume, and expiratory reserve volume ($ERV$).

Forced Vital Capacity (FVC)

The total volume of air that can be exhaled as fast and as forcefully as possible after a maximum inhalation.

$FEV_1/FVC$ Ratio

A lung status indicator where a value over $70\%$ is considered normal, indicating a lack of obstructive disease.

Mucociliary Escalator

The process by which ciliated pseudostratified columnar epithelium and mucus-producing goblet cells move trapped materials upward toward the pharynx.

Surfactant

A product secreted by Type II cells in the alveoli that reduces surface tension to prevent the alveoli from collapsing during exhalation.

Compliance

The ability of the lungs to expand easily, facilitated by the presence of pleural fluid.

Atmospheric Pressure

The pushing force of the atmosphere, quantified as $760\,mm\,Hg$ at sea level.

Accessory Inhalation Muscles

Muscles used during forced breathing to elevate the ribs, including the scalenes, sternophytomastoid, serratus anterior, and pectoralis minor.

Accessory Exhalation Muscles

Muscles that contract to pull the ribs down during forced exhalation, including the internal intercostals and rectus abdominis.

Carbonic Anhydrase

The enzyme that manages carbon dioxide by catalyzing the reversible reaction: $CO_2 + H_2O \rightleftharpoons H_2CO_3 \rightleftharpoons H^+ + HCO_3^-$.

Chloride Shift

The mechanism where a transporter in the red blood cell or parietal cell membrane exchanges a bicarbonate ion ($HCO_3^-$) for a chloride ion ($Cl^-$) to maintain electrical charge.

Parietal Cells

Stomach cells located in the gastric glands that produce hydrochloric acid ($HCl$) and intrinsic factor.

G Cells

Endocrine cells in the stomach that release the hormone gastrin, which stimulates parietal cells to increase acid production.

Intrinsic Factor

A glycoprotein produced by parietal cells that is required for the absorption of vitamin $B_{12}$; a deficiency leads to pernicious anemia.

Chief Cells

Stomach cells that secrete pepsinogen, an inactive protease that is activated into pepsin by hydrochloric acid ($HCl$).

Secretin

A hormone released by the duodenum in response to acids that tells the pancreas to release sodium bicarbonate to raise the chyme's pH to approximately $8$.

CCK (Cholecystokinin)

A hormone released by the duodenum in response to fats that triggers the liver and gallbladder to release bile for fat emulsification.

Bile

A detergent-like substance produced by the liver and stored in the gallbladder that emulsifies large lipid globules into small droplets to increase surface area for lipase.

Chylomicron

A large lipoprotein transport vehicle formed by villous cells to carry absorbed lipids into the lymphatic system.

Lacteal

A specialized lymph capillary inside the intestinal villi that absorbs large chylomicrons that are too big for blood capillaries.