Respiratory, Urinary, and Digestive Systems Review

Comprehensive vocabulary flashcards covering the anatomy, physiology, and hormonal regulation of the respiratory, urinary, and digestive systems based on lecture notes.

Cellular respiration

The process where cells require oxygen to break down nutrients such as glucose to create $ATP$ (adenosine triphosphate).

Ventilation

The movement of air between the atmosphere and the alveoli, also known as pulmonary ventilation or breathing.

External respiration

The diffusion of gases across the respiratory membrane between the alveoli and the pulmonary capillaries.

Internal respiration

Also called tissue respiration, it is the process where $O_2$ diffuses from the blood in systemic capillaries to cells, and $CO_2$ diffuses from cells to the blood.

Nasal conchae

Three scroll-like bony projections that increase surface area for heating/moistening air and create turbulence to trap particles against mucus.

Glottis

The opening between the vocal cords through which air moves; it is open during breathing and speaking and closed during swallowing or coughing.

Valsalva's manoeuvre

The contraction of abdominal muscles while the glottis is closed to increase intra-abdominal pressure.

Mucociliary escalator

The movement of debris-laden mucus toward the pharynx by the action of cilia.

Bronchioles

Airways less than $1\,\text{mm}$ in diameter that lack cartilage and are surrounded by smooth muscle for regulation of airway diameter.

Type 2 alveolar cells

Cells that secrete surfactant to reduce surface tension inside the alveoli and prevent them from collapsing between breaths.

Pleura

A separate, double-layered serous membrane surrounding each lung, consisting of visceral and parietal layers.

Cardiac notch

The indentation on the surface of the left lung that allows space for the heart.

Conducting zone

Respiratory passageways that clean, warm, and humidify incoming air but do not participate in gas exchange.

Tidal volume (TV)

The volume of air inhaled or exhaled under resting conditions, typically around $500\,\text{mL}$.

Anatomical dead space

Air located in the conducting zone (approximately $150\,\text{mL}$) that is not available for gas exchange.

Bicarbonate buffer equation

$$CO_2 + H_2O \rightleftharpoons H_2CO_3 \rightleftharpoons HCO_3^- + H^+$$

Retroperitoneal

The anatomical location of the kidneys, meaning they are situated behind the peritoneum.

Nephron

The microscopic structural and functional unit of the kidney, with approximately one million per kidney.

Glomerulus

A knot of fenestrated capillaries within the renal corpuscle where blood filtration occurs.

Podocytes

Specialized cells forming the visceral layer of the glomerular capsule with pedicels that create filtration slits.

Glomerular filtration rate (GFR)

The rate of filtrate production, which is approximately $120\text{--}125\,\text{mL/min}$ in healthy kidneys.

Detrusor muscle

The thick smooth muscle layer in the wall of the urinary bladder that contracts during micturition.

Rugae

Internal folds in the bladder or stomach mucosa that allow the organs to expand as they fill.

Trigone

The triangular area formed by the openings of the two ureters and the urethra in the bladder wall.

Tubular reabsorption

The process of moving water and useful substances from the filtrate in the renal tubules back into the blood.

Antidiuretic hormone (ADH)

A hormone from the posterior pituitary that increases water reabsorption in the kidneys, making urine more concentrated.

Aldosterone

A hormone from the adrenal glands that causes the kidneys to reabsorb sodium and water while excreting potassium.

Atrial Natriuretic Peptide (ANP)

A hormone released by the atria of the heart that increases sodium and water excretion to lower blood pressure.

Alimentary canal

The continuous tube of the digestive tract organs extending from the mouth to the anus.

Peristalsis

Rhythmic contractions of circular and longitudinal smooth muscle that propel contents along the digestive tract.

Segmentation

Alternating ring-like contractions of the small intestine that mix secretions with food/chyme.

Mesentery

An extension of the visceral peritoneum that attaches organs to the posterior abdominal wall and supports vessels and nerves.

Pepsin

An enzyme activated by $HCl$ that breaks down proteins into polypeptides in the stomach.

Chyme

The creamy paste formed when swallowed food is combined with gastric juice in the stomach.

Parietal cells

Stomach cells that secrete hydrochloric acid ($HCl$) and intrinsic factor.

Bile

A yellow-green alkaline solution produced by the liver that emulsifies fats to increase surface area for lipase.

Teniae coli

Three bands of smooth muscle in the longitudinal muscularis of the large intestine.

Gastrin

A hormone released by the stomach in response to food that increases $HCl$ secretion and gastric motility.

Cholecystokinin (CCK)

A duodenal hormone stimulated by fatty chyme that triggers gallbladder contraction and pancreatic enzyme release.

Secretin

A duodenal hormone stimulated by acidic chyme that promotes bicarbonate-rich pancreatic juice secretion and inhibits gastric activity.