Chapter 47: Gas Exchange

Vocabulary flashcards covering the mechanisms, structures, and biological components of gas exchange in various organisms.

Partial Pressure

The concentration of a gas in a mixture.

Ventilation

The active moving of air or water over gas exchange surfaces.

Perfusion

Circulating blood over the internal side of gas exchange surfaces.

Spiracles

Openings in the abdomen of insects that allow for gas exchange.

Intercostal muscles

Muscles that can change the volume of the thoracic cavity.

Myoglobin

A single polypeptide molecule in muscle cells that can bind 1 $O_2$ molecule.

Red blood cells (adaptation to low oxygen)

Cells that increase glycolysis and convert $1,3\text{-BPG}$ to $2,3\text{-BPG}$ to help in low oxygen environments.

Surfactant

Fluid in the alveoli that reduces surface tension.

Carotid Bodies

Sensors in the neck arteries that monitor the blood.

Hemoglobin

Iron-rich protein in red blood cells that transports $O_2$ through the body.

Tidal flow

A 1 way, breathing system.

Diaphragm

A muscle under the lungs that contracts downward to pull air in.

Countercurrent flow

Water and blood moving in opposite directions, which maximizes oxygen absorption.

Tracheal

A network of air tubes in insects that delivers $O_2$ to tissues.

Gills

External organs used by aquatic animals to get $O_2$ from $H_2O$.

Lungs

Internal, sac-like organs that perform gas exchange in land animals.

Alveoli

Tiny, grape-like air sacs in mammalian lungs where gas exchange happens in the blood.

Central Chemoreceptors

Brain sensors that monitor fluid pH to tell you when to breathe faster or slower.

Pre-Bötzinger Complex

The pacemaker nerve center in the brainstem that sets your automatic breathing rhythm.

Bicarbonate Ion

The main chemical form (about 70%) used to carry $\text{CO}_2$ waste through the bloodstream.

Carbonic Anhydrase

The blood enzyme that instantly turns CO2 gas into liquid bicarbonate for safe transport.

2,3-BPG

A blood chemical that forces hemoglobin to release its oxygen during exercise or at high altitudes.

Haldane Effect

Deoxygenated blood is better at carrying CO2 waste away from tissues.

Bohr Effect

High CO2 or high acid causes hemoglobin to dump its oxygen into working tissues.

Transpulmonic Pressure

The pressure difference between the inside and outside of the lungs that keeps them inflated.

Dead Space

Inhaled air trapped in the throat and airways that never reaches the gas-exchange area.

Bronchioles

Tiny, narrow branches of the airways that lead air directly into the alveoli.

Unidirectional Flow

One-way airflow (in birds) that allows fresh air to move through the lungs during both breath in and breath out

Air Sacs

Bellows-like bags in birds that pump air through the lungs in a one-way loop.

Parabronchi

Tiny parallel tubes in a bird's lung where air flows continuously in one direction.

Perfusion

Blood flow through tissue capillaries that keeps gas exchange moving.

Fick’s Law

The rule that gas diffuses faster with more surface area, but slower through thicker membranes.

Boundary Layer

A trapped layer of still air or fluid on a respiratory surface that slows down gas exchange.