Respiratory System - Vocabulary

Flashcards covering key vocabulary from respiratory system lectures.

Little a

Arterial pressure of CO2, blood pH that the body is adjusting to get back into homeostasis

Chemoreceptors

Detects blood gasses or pH and sends signals to the dorsal and ventral respiratory groups in the brainstem.

Upper Airway

Nose to larynx (voice box)

Nasal Cavity

Humidifies, warms, and cleans air.

Lower Airway

Trachea to alveoli.

Terminal Bronchiole

Brings air to gas exchange site

Respiratory Zone

Site where gas exchange takes place.

Alveolar Ducts and Sacs

Produce surfactant, which minimizes surface tension and allows alveoli to stay open as much as possible

Pulmonary Circuit

Blood traveling from the heart to the lungs for gas exchange and back to the heart.

Systemic Circuit

Oxygenated blood out to the rest of the body for cellular gas exchange.

Respiratory Membrane

Surface across which gas exchange happens in the lungs; one side is air, the other side is blood.

Hemoglobin (Hb)

Comprised of red heme pigment bound to protein: globin; enables oxygen to be bound in blood.

Atmospheric Pressure

Pressure exerted by air surrounding the body

Intrapulmonary Pressure (PPul)

Pressure in alveoli

Intrapleural Pressure (Pip)

Pressure in pleural cavity (visceral pleura and parietal pleura)

Transpulmonary Pressure (Ptp)

Difference between intrapulmonary and intrapleural pressure

Boyle's Law

States that pressure is inversely related to volume

Tidal Volume (Vt)

Volume of air entering and leaving the lungs with each breath

Inspiratory reserve volume (IRV)

The amount of air that can be inspired in addition to the Vt

Expiratory reserve volume (ERV)

Amount of air that can be removed from lung beyond Vt

Residual volume (RV)

Air volume in lung even after max expiration

Total lung capacity (TLC)

Maximum amount of air contained in lungs after maximum inspiration

Vital capacity (VC)

Maximum amount of air that can be expired after a maximum inspiration

Inspiratory capacity (IC)

Maximum amount of air that can be inspired after a normal tidal volume expiration

Functional residual capacity (FRC)

Volume of air remaining in lungs after normal tidal volume expiration

Diffusion

Way gas moves around in parts of lung involved in gas exchange

Henry's Law

relationship between parietal pressure and dissolving speed of gas in a liquid

Eupnea

Normal, quiet breathing

Hyperventilation

Over-breathing, results in reduction in PaCO2

Hypoventilation

Under-breathing, results in increase if PaCO2

Aponea

Absence of breathing (at least 10 sec)

Bradypnea

Abnormal slowness of breathing

Tachypnea

Rapid breathing

Dyspnoea

Sensation of breathlessness

Hyperpnoea

Increased ventilation in proportion to metabolic demand

Dead Space

Region ventilated but not perfused

Alveolar dead space

Ventilated alveoli that do not receive any blood flow

Physiological Shunt

blood is deoxygenated

Anatomical (arteriovenous) shunts

Blood by-passes alveoli completely

Systolic Blood Pressure (SBP)

arterial - heart is beating

Diastolic Blood Pressure (DBP)

heart is relaxed and ventricle fills with blood

Blood vessels in lungs constrict under presence of certain levels of low oxygen

Pulmonary Hypoxia

First result of respiratory control

modification of tidal volume (the amount of air that you are breathing in)

Respiratory cycle

Is comprised of several phases:

• Inspiratory time
• Expiratory time
• Post-inspiratory pause
• Post-expiratory pause = total respiratory time (TTOT)

First need of ventilatory control mechanisms

Establish automatic rhythm for contraction of respiratory muscles (diaphragm and external intercostals)

Galen

2nd century physician to greek gladiators
Discovered: that if you had a sword injury in this area of the spine -> that's when you stop your breathing and it will be fatal

Central Pattern Generator (CPG)

Clock that times the automatic cycle of inspiration and expiration (regular ticking during sleep, quiet wakefulness)

Central chemoreceptors

Located in the brain and protected by blood-brain barrier, responds to CO2 concentration

Peripheral Chemoreceptors

Located in the carotid body in bifurcation between internal carotid artery going up to the brain and the external carotid artery going up to the face and the scalp, respond to changes in O2 and CO2

Acidosis

Increase in CO2 -> co2 combines with water to produce carbonic acid so my carbonates are produced

Metabolic acidosis

No change in co2, and have a reduction in carbonate due to renal failure and using buffers to mop up the acid

Respiratory-Related Neurons (RRN)

neurons in brainstem that fire action potentials more rapidly during different times in respiratory cycle

Dorsal Respiratory Group (DRG)

Bilateral group of neurons extend ~⅓ of the medulla, located at the base of the 4th ventricle, primarily contains inspiratory neurons
Integrates sensory input to VRG

Ventral Respiratory Group (VRG)

Bilateral group of neurons extend length of medulla (lateral) - major efferent motor