Lymphatic, Respiratory, and Digestive Systems Overview

Vocabulary flashcards summarizing essential terms from the lymphatic, respiratory, and digestive system lecture notes.

Lymphatic Vessels

One-way tubes that carry lymph toward the heart and return excess tissue fluid to the bloodstream.

Lymph

Fluid inside lymphatic vessels composed of plasma, proteins, and immune cells.

Lymphoid Tissue

Reticular connective tissue packed with phagocytes and lymphocytes for immune defense.

Right Lymphatic Duct

Drains lymph from the right head, right thorax, and right arm into the venous circulation.

Thoracic Duct

Largest lymphatic duct; drains lymph from the rest of the body.

Lacteals

Specialized intestinal lymph capillaries that absorb dietary fats into the bloodstream.

Lymphangitis

Inflammation of lymphatic vessels, typically due to infection.

Lymphedema

Tissue swelling caused by obstruction of lymphatic drainage.

Lymphoma

Cancerous tumor of lymphatic tissue.

T Cells

Lymphocytes that provide cell-mediated immunity by directly attacking infected or abnormal cells.

B Cells

Lymphocytes that differentiate into plasma cells to secrete antibodies for humoral immunity.

Humoral Immunity

Indirect immune defense mediated by antibodies circulating in body fluids.

Cell-Mediated Immunity

Direct immune defense in which T cells destroy infected or foreign cells.

Pulmonary Ventilation

Breathing; movement of air into and out of the lungs.

External Respiration

Gas exchange between air in the lungs and blood in pulmonary capillaries.

Transport of Respiratory Gases

Movement of O₂ and CO₂ in the blood, mainly via hemoglobin and plasma.

Internal Respiration

Gas exchange between systemic capillary blood and body tissues.

Conducting Zone

Passageways from nose to terminal bronchioles that warm, filter, and transport air.

Respiratory Zone

Structures from respiratory bronchioles to alveoli where gas exchange occurs.

Paranasal Sinuses

Frontal, sphenoid, ethmoid, and maxillary air-filled cavities that lighten the skull and condition air.

Sinusitis

Inflammation of the paranasal sinuses causing blocked drainage and pressure.

Rhinitis

Inflammation of the nasal mucosa, often spreading to nearby regions.

Nasopharynx

Superior pharyngeal region posterior to the nasal cavity; closed by soft palate during swallowing.

Oropharynx

Middle pharyngeal region behind the oral cavity; conducts food and air; houses palatine and lingual tonsils.

Laryngopharynx

Inferior pharyngeal region leading to larynx and esophagus; lined with stratified squamous epithelium.

Larynx

Voice box connecting pharynx to trachea; keeps airway open, routes food/air, and produces voice.

Epiglottis

Elastic cartilage flap that covers the laryngeal inlet during swallowing.

True Vocal Cords

Vocal folds that vibrate to create sound.

False Vocal Cords

Vestibular folds that help close the glottis but do not produce sound.

Glottis

Opening between the vocal cords.

Valsalva’s Maneuver

Forced exhalation against a closed glottis to stabilize trunk or aid defecation/childbirth.

Trachea

Windpipe supported by C-shaped cartilage; lined with pseudostratified ciliated epithelium.

Bronchial Tree

Branching airways from main bronchi to respiratory bronchioles and alveoli.

Main (Primary) Bronchi

First branches of the trachea; right is shorter, wider, and more vertical.

Bronchioles

Small airways lacking cartilage; diameter <1 mm.

Terminal Bronchioles

Last part of the conducting zone; lead to respiratory bronchioles.

Respiratory Bronchioles

First part of respiratory zone containing some alveoli.

Alveoli

Microscopic air sacs where gas exchange occurs.

Type I Alveolar Cells

Simple squamous cells forming most of the alveolar wall for gas diffusion.

Type II Alveolar Cells

Cuboidal cells that secrete surfactant to lower surface tension.

Surfactant

Detergent-like secretion that reduces alveolar surface tension and prevents collapse.

Alveolar Macrophages

Dust cells that remove debris and pathogens from alveolar surfaces.

Alveolar Pores

Openings connecting adjacent alveoli to equalize air pressure.

Apex (of Lung)

Superior pointed tip of a lung.

Base (of Lung)

Broad inferior surface resting on the diaphragm.

Hilum (Lung)

Medial indentation where bronchi, vessels, and nerves enter/leave the lung.

Cardiac Notch

Indentation in the left lung accommodating the heart.

Angiotensin-Converting Enzyme (ACE)

Enzyme in lung endothelium that converts angiotensin I to vasoconstrictor angiotensin II.

Visceral Pleura

Serous membrane covering lung surfaces.

Parietal Pleura

Serous membrane lining the thoracic wall and diaphragm.

Pleural Fluid

Lubricating fluid between pleural layers that reduces friction and aids lung expansion.

Pleuritis

Inflammation of pleura causing sharp pain during breathing.

Boyle’s Law

Gas law stating pressure is inversely related to volume (P↑ as V↓ and vice versa).

Atmospheric Pressure (Patm)

Air pressure outside the body (~760 mmHg at sea level).

Intrapulmonary Pressure (Ppul)

Pressure within alveoli, equalizes with Patm.

Intrapleural Pressure (Pip)

Pressure within pleural cavity, always negative to keep lungs inflated.

Atelectasis

Lung collapse from airway blockage or loss of negative Pip.

Pneumothorax

Air in the pleural cavity leading to lung collapse; treated with chest tube.

Airway Resistance

Opposition to airflow, greatest in medium-sized bronchi; reduced by epinephrine.

Lung Compliance

Ease with which lungs expand; decreased by fibrosis, low surfactant, or chest rigidity.

Alimentary Canal (GI Tract)

Continuous tube from mouth to anus where digestion and absorption occur.

Mucosa

Innermost GI layer; mostly simple columnar epithelium with mucus-secreting cells.

Submucosa

Connective tissue layer housing blood vessels, nerves, and lymphatics.

Muscularis Externa

Two smooth muscle layers (circular and longitudinal) that drive GI motility.

Serosa

Outer visceral peritoneum covering intraperitoneal organs.

Adventitia

Fibrous outer layer of retroperitoneal organs such as the esophagus.

Accessory Digestive Organs

Teeth, tongue, salivary glands, liver, gallbladder, pancreas; aid digestion without food passage.

Peristalsis

Wave-like contractions propelling food through the GI tract.

Segmentation

Rhythmic local contractions mixing chyme and enhancing absorption, mainly in small intestine.

Peritoneum

Serous membrane lining abdominopelvic cavity (parietal) and covering organs (visceral).

Peritoneal Cavity

Space between peritoneal layers containing lubricating serous fluid.

Mesentery

Double layer of peritoneum that anchors organs, stores fat, and contains vessels and nerves.

Intraperitoneal Organ

GI organ almost fully wrapped by visceral peritoneum and suspended by mesentery.

Retroperitoneal Organ

Organ positioned posterior to the peritoneum and only partly covered by it.

Peritonitis

Inflammation of the peritoneum, often from infection or abdominal trauma.

Parotid Gland

Largest salivary gland near ear; produces serous saliva rich in amylase.

Mumps

Viral infection causing painful inflammation of parotid glands.

Submandibular Gland

Salivary gland under the jaw secreting mixed serous and mucous saliva.

Sublingual Gland

Smallest major salivary gland under the tongue; mostly mucous secretion.

Salivary Amylase

Enzyme in saliva initiating starch digestion.

Lingual Lipase

Enzyme secreted by tongue glands; begins fat digestion in the stomach.

Mucin

Glycoprotein that forms lubricating mucus when hydrated.

Esophagus

Muscular tube with stratified squamous epithelium transporting food to the stomach.

Gastroesophageal Reflux Disease (GERD)

Chronic acid reflux causing heartburn and potential esophageal damage.

Esophageal Ulcer

Open sore in esophageal lining, often a complication of GERD.

Fundus (Stomach)

Dome-shaped region of the stomach superior to the cardia.

Pyloric Sphincter

Smooth muscle ring regulating chyme entry into the duodenum.

Rugae

Folds in empty stomach mucosa allowing expansion when filled.

Gastric Glands

Glands in stomach mucosa secreting gastric juice (HCl, enzymes, mucus).

Mucosal Barrier

Protective trio of bicarbonate mucus, tight junctions, and rapid cell turnover shielding stomach lining.

Peptic Ulcer

Erosion of stomach or duodenal wall, often due to H. pylori or NSAIDs.

Helicobacter pylori

Bacterium that colonizes stomach and weakens mucosal barrier, leading to ulcers.

Intrinsic Factor

Stomach glycoprotein essential for vitamin B₁₂ absorption.

Dumping Syndrome

Rapid gastric emptying into small intestine, common after stomach surgery.

Duodenum

First small-intestine segment receiving bile and pancreatic juice.

Jejunum

Middle portion of the small intestine, major site of absorption.

Ileum

Distal small-intestine segment connecting to the large intestine.

Hepatocytes

Liver cells that process nutrients, detoxify blood, and produce bile.

Portal Triad

Corner of liver lobule containing hepatic artery, portal vein, and bile duct.

Cirrhosis

Chronic liver scarring impairing function; often due to alcoholism or hepatitis.