Exam 3: Into to Respiration

Alveolar Ventilation

The portion of the tidal volume that reaches the alveolar compartment for gas exchange.

Va=Vt-Vd

Alveoli

Tiny air sacs within the lungs where gas exchange occurs.

Compliance

A measure of lung distensibility; the ease with which the lung can be inflated.

Conducting Zone

The passageways of the respiratory system that filter, humidify, and conduct air to the lungs.

Chronic Obstructive Pulmonary Disease; a condition of decreased expiratory airflow from constant, irreversible airway narrowing.

COPD

Dalton's Law

The total pressure of a gas mixture is equal to the sum of the pressure that each gas would exert independently.

Dead Space Ventilation

The portion of tidal volume that does not reach the alveolar compartment (gas trapped in the conducting zone).

Diffusion

The random movement of molecules from an area of high concentration to an area of lower concentration.

Fick's Law of Diffusion

A law stating that the rate of gas transfer is proportional to the tissue area and pressure difference, and inversely proportional to the tissue thickness.

Hypercapnia

A condition of high carbon dioxide (CO2) levels.

Hypoxia

A condition of low oxygen (O2) levels.

Myoglobin (Mb)

An oxygen-binding protein found in skeletal muscle that shuttles O2 from the cell membrane to the mitochondria.

- has a higher affinity for O2 than hemoglobin

Pleura

The membranes (visceral and parietal) that surround the lungs.

Pneumothorax

A condition where air enters the pleural space due to a punctured chest wall, causing the lung to shrink.

Respiratory Zone

The region of the lungs where gas exchange occurs, including the respiratory bronchioles and alveoli.

Surfactant

substance made by alveolar cells that lowers the surface tension of the alveoli, preventing their collapse.

Tidal Volume (VT)

The amount of gas moved per breath.

Ventilation

The mechanical process of moving air into and out of the lungs.

exchange of O2 and CO2 at the lungs

Ventilation/Perfusion Ratio (V/Q)

The ratio of alveolar ventilation to blood flow; indicates the matching of blood flow to ventilation. Ideal is 1.0 or higher

cellular respiration

O2 utilization and CO2 production by the tissues

circulatory transport

transport of respiratory gases in the blood between the lungs to the cells of the body

systemic gas exchange

the movement of respiratory gases from the blood into the cells of the body (diffusion)

- O2 diffuses from blood to cells

- CO2 diffuses from cells to venous blood

alveolar gas exchange

movement of alveolar gases via diffusion

O2 tension in alveolar region > O2 tension in blood = O2 diffuses to blood

CO2 tension in alveolar region < CO2 tension in blood = CO2 moves to lungs

trigger vasoconstriction to divert blood flow to areas of improved ventilation

How does local hypoxia affect Pulmonary Circulation

nose, nasal cavity, pharynx

Organs of upper respiratory system

larynx, trachea, bronchial tree, lungs

organs of lower respiratory system

Diaphragm and phrenic nerve

major muscle of inspiration and its nerve

conducting zone

Includes respiratory passageways, cleanses, humidifies and warms incoming air

respiratory zone

Site of gas exchange in lungs.

respiratory bronchioles, alveolar ducts, alveolar sacs

Capillaries

gas exchange occurs at what blood vessel

inspiration

When the pressure in the lungs becomes less than atm pressure, what happens

expiration

When the pressure in the lungs becomes greater than atm pressure what happens

contracts, below

during inspiration, the diaphragm __________, which forces the abdominal contents down and lifts the ribs outward increasing the thoracic cavity dimensions and the lungs can expand, decreasing intrapulmonary pressure _______ atm pressure and air flows in

Accessory Muscles (external intercostals, pec minor, serratus anterior, scalene muscles, SCM)

needed during exercise to assist diaphragm in increasing chest dimensions

abdominal wall muscles (rectus abdominis and external obliques

most important muscles in expiration, which is passive at rest, and active during exercise

surface tension

what is responsible for most of the lungs ability to be elastic and recoil

emphysema

a condition in which the air sacs of the lungs are damaged and enlarged, causing breathlessness.

high compliance, ease of lung inflation

pulmonary fibrosis

formation of scar tissue in the connective tissue of the lungs

low compliance

Histamine

triggers smooth muscle contraction

airflow

P1-P2/resistance

resistance

depends on the diameter of airway

Volume of gas

V = Vt x f

underperfused

blood flow (perfusion) is less than ventilation, V/Q ratio >1.0, standing at rest, apex of the lung

overperfused

blood flow is greater than ventilation, V/Q ratio <1.0 standing at rest

oxygen hemoglobin dissociation curve

describes the percentage of hemoglobin saturated with oxygen at any given PO2

- at rest 25% O2 transported in blood unloaded at the tissues

lowers affinity

a decrease in pH and an increase in temperature do what for hemoglobin affinity for O2 and favors offloading of O2 to the tissues

right

a lower Hb-O2​ affinity shifts the oxygen-hemoglobin dissociation curve to the ______, signifying that O2​ is more easily released to meet the metabolic demands of the tissues.

2-3 DPG

biproduct of RBC glycolysis

can combine with hemoglobin (Hb) and decrease Hb affinity for O2

increases during altitude exposure and anemia

Bicarbonate (HCO3-) (70%)

bound to Hemoglobin (20%)

dissolved in plasma (10%)

3 ways CO2 is transported in blood (highest to lowest)

Lungs

only organ in body to receive 100% of cardiac output