Respiratory and Digestive Systems

Flashcards from Respiratory and Digestive System Lecture Notes

Unidirectional Flow

Water flows in one direction across the respiratory structures (gills); air passes through only once.

Bidirectional Flow (Tidal)

Air flows in and out of the same respiratory passage (lungs).

Internal Gills

Associated with pharyngeal slits and pouches; usually covered for protection.

External Gills

Found in larvae of many vertebrates; require constant water flow for ventilation.

Spiracle

The first gill slit in Gnathostomes.

Eustachian Tube

Normalizes air pressure in the middle ear cavity.

Faveoli

Compartments in amphibian lungs where gas exchange occurs; not found at the end of a highly branched bronchial system.

Buccal Pump

A mechanism for air ventilation, forcing air into the lungs, found in amphibians and some air-breathing fish.

Cutaneous Respiration

Gas exchange primarily occurs through the skin.

Aspiration Pump

Mechanism where rib movement changes the body wall around the lungs, allowing air to flow in or out (Reptiles).

Ventral Respiratory Group (VRG)

Primary generator of basic respiratory rhythm (BRS); controls both inspiration and expiration.

Dorsal Respiratory Group (DRG)

Modifies BRS by modulating the VRG; controls quiet breathing.

Pontine Respiratory Group (PRG)

Fine-tunes breathing rhythm by controlling transitions from inspiration to expiration.

Central Chemoreceptors

Reflects changes in CO2 levels in the blood; changes in cerebrospinal pH.

Peripheral Chemoreceptors

Detects O2 and CO2 levels in the blood in the Carotid and Aortic Bodies.

Stretch Receptors

Respond to the inflation of the lungs; triggers the Hering-Breuer reflex.

Irritant Receptors

Triggers protective reflexes like bronchoconstriction, breath-holding, and coughing.

Alveolar Macrophages

Most abundant cells in the alveoli; cleanse and protect the lungs from foreign materials.

Squamous Alveolar Cells

Thin cells that cover 95% of the alveoli surface for rapid gas exchange.

Great Alveolar Cells

Repair the epithelium when damaged and secrete pulmonary surfactant.

Respiratory Membrane

The region where gas exchange occurs in the lungs.

Digestion (Mechanical)

Physical breakdown of food into smaller particles without chemical change.

Digestion (Chemical)

Chemical breakdown of food from large bio-molecules into absorbable forms.

Cecum

The pouch where bacteria are housed in herbivores without a rumen.

Rumen

The first chamber in the stomach of ruminants where bacteria fermentation happens.

Crop

Temporary storage of food in chickens; a pouch in the esophagus.

Gizzard/Ventriculus

True stomach in birds; specialized for grinding food with pebbles.

Glycogenesis

Storing excess glucose as glycogen.

Glycogenolysis

Releasing glucose from glycogen when needed.

Gluconeogenesis

Synthesizing glucose from fats and amino acids.

Lipogenesis

Fat synthesis.

Chylomicrons

Transports cholesterol, phospholipids, and fat-soluble vitamins.

Micelles

Aid in the absorption of dietary lipids.

Hepatic Duct

Carries bile from the liver to the duodenum.

Pancreatic Duct

Carries Pancreatic Juice.

Trypsinogen

Inactive precursor to Trypsin.

Zymogens

Inactive precursors of digestive enzymes secreted by the pancreas.

Founder Species

Initial gut bacteria which establish in newborns.

Symbiotic Microbes

Microbes which may influence neurodevelopment and social behaviors.

Microbiota

Bacteria that can affect cognitive function, affect Gut Brain Axis via Vagus Nerve.