Respiratory, Digestive, and Urinary Systems – Lecture Review

Question-and-answer flashcards covering major anatomy, physiology, and clinical correlations from the lecture notes.

What are three primary functions of the nose and nasal cavity?

Filtering, warming, and humidifying incoming air (and housing olfactory receptors).

Which region of the pharynx is strictly an air passage located behind the nasal cavity?

The nasopharynx.

What shared pathway for food and air lies behind the oral cavity?

The oropharynx.

Into which two structures does the laryngopharynx lead?

The larynx and the esophagus.

How does the larynx prevent food from entering the trachea?

The epiglottis closes off the airway during swallowing.

Which rings support the trachea and keep it open?

C-shaped cartilage rings.

What specialized epithelium lines the trachea and helps move mucus upward?

Ciliated epithelium with mucus-secreting cells.

How many secondary (lobar) bronchi are found in the right and left lungs respectively?

Three on the right and two on the left.

What is the main function of bronchioles’ smooth muscle?

To regulate airflow through bronchoconstriction or bronchodilation.

Approximately how many alveoli are in the human lungs?

Over 300 million.

What is the primary site of gas exchange in the respiratory system?

The alveoli, across their thin squamous walls and surrounding capillaries.

Name the two layers of the pleura.

Visceral pleura (on lungs) and parietal pleura (lining the thoracic cavity).

During inhalation, what happens to the diaphragm and thoracic cavity volume?

The diaphragm contracts and moves downward, increasing thoracic volume so air flows in.

Where does external respiration occur?

Between alveolar air and blood in pulmonary capillaries.

In what molecular forms is carbon dioxide transported back to the lungs?

Mostly as bicarbonate ions in plasma, with some bound to hemoglobin or dissolved.

What term describes gas exchange between systemic capillaries and body tissues?

Internal respiration.

List three protective filtering mechanisms of the respiratory tract.

Mucus, cilia, and nasal hairs (plus reflex coughing/sneezing).

Where are olfactory receptors located?

In the olfactory epithelium of the nasal cavity.

Which airways are primarily narrowed and inflamed in COPD?

The bronchi and bronchioles.

What structural change occurs to alveoli in emphysema?

Destruction of alveolar walls and loss of elasticity, forming bullae.

Name two key anatomical changes seen in asthma.

Bronchoconstriction and mucosal edema with mucus plugging (airway remodeling).

What is the parietal layer of a serous membrane?

The layer that lines the walls of a body cavity.

Which serous membrane surrounds the heart?

The pericardium.

How many permanent adult teeth are typically present?

Thirty-two.

Which enzyme in saliva begins starch digestion?

Salivary amylase.

What is the function of the soft palate during swallowing?

To close off the nasopharynx, preventing food from entering the nasal cavity.

Name the two esophageal sphincters.

Upper esophageal sphincter (UES) and lower esophageal sphincter (LES).

What are the three layers of smooth muscle in the stomach wall?

Longitudinal, circular, and oblique layers.

What are rugae and what is their purpose?

Folds in the stomach mucosa that allow expansion as the stomach fills.

Which stomach cells secrete hydrochloric acid?

Parietal cells.

Which stomach cells secrete pepsinogen?

Chief cells.

What are the three sections of the small intestine in order?

Duodenum, jejunum, and ileum.

Which structural adaptations of the small intestine greatly increase surface area for absorption?

Plicae circulares, villi, and microvilli.

What nutrients are absorbed by lacteals within villi?

Dietary fats (as chylomicrons).

What lymphatic structures in the ileum monitor intestinal pathogens?

Peyer’s patches.

Name the pouch-like segments of the large intestine.

Haustra.

What are the longitudinal muscle bands of the colon called?

Teniae coli.

Which cells in the large intestine secrete mucus to lubricate feces?

Goblet cells.

List three major functions of the liver.

Produces bile, processes nutrients, and detoxifies blood.

What is the primary function of the gallbladder?

To store and concentrate bile until it is needed in the duodenum.

Which pancreatic cells secrete digestive enzymes?

Acinar cells.

Through which structure do the common bile duct and pancreatic duct empty into the duodenum?

The hepatopancreatic ampulla (ampulla of Vater) at the major duodenal papilla.

What is the role of bile in digestion?

It emulsifies fats, increasing their surface area for pancreatic lipase.

How does the pyloric sphincter aid digestion?

It regulates the controlled release of chyme from the stomach into the duodenum.

In celiac disease, what intestinal structures are primarily damaged?

The villi and microvilli of the small-intestinal mucosa (especially jejunum).

What is the consequence of villous atrophy in celiac disease?

Decreased nutrient absorption leading to malnutrition, diarrhea, and weight loss.

Which enzyme deficiency causes lactose intolerance?

Lactase deficiency in the brush-border of enterocytes.

Why does lactose intolerance cause bloating and gas?

Undigested lactose is fermented by colonic bacteria, producing gas and osmotic diarrhea.

Where are the kidneys located relative to the peritoneum?

Retroperitoneal, on either side of the vertebral column between T12 and L3.

What is the functional unit of the kidney?

The nephron.

Which part of the nephron is responsible for most reabsorption of nutrients, water, and ions?

The proximal convoluted tubule (PCT).

What nephron segment creates the concentration gradient in the medulla?

The loop of Henle (descending and ascending limbs).

Which nephron segment is largely regulated by hormones such as aldosterone and ADH?

The distal convoluted tubule (DCT) and collecting duct.

Name two hormones produced by the kidneys.

Erythropoietin and renin (plus activation of vitamin D).

What is the function of the ureters?

To propel urine from the renal pelvis to the bladder via peristalsis.

What triangular region of the bladder is prone to infections and bounded by ureter and urethral openings?

The trigone.

Approximately how much urine can the bladder comfortably store?

About 500 milliliters.

How long is the male urethra compared to the female urethra?

Male ≈ 18–20 cm; female ≈ 4 cm.

Why are females more prone to urinary tract infections than males?

Because the female urethra is shorter and closer to the anal region, allowing easier bacterial ascent.

What type of muscle forms the involuntary internal anal sphincter?

Smooth muscle (the external anal sphincter is voluntary skeletal muscle).