a&p ch 21: processes of respiration

Define external respiration.

All the processes involved in the exchange of O2 & CO2 bw blood, lungs, & external environment

Explain the decrease in the PO2 from the pulmonary venules to the blood arriving in the peripheral capillaries of the systemic unit.

PO2 decreases from 100 mmHg to 95 mmHg in the pulmonary veins as it mixes with venous blood from capillaries surrounding the conducting passageways blood arriving at the peripheral caps has a PO2 of 95 mmHg

What is ventilation?

Physical movement of air

What is the significance of Henry's Law to the process of respiration?

at a given T, the amt of particular gas that dissolves in a liquid is directly proportional to the partial P of that gas H's Law underlies the diffusion of gases bw capillaries & alveoli AND bw capillaries & interstitial fluid

Define oxyhemoglobin.

hemoglobin bound to oxygen

During exercise, hemoglobin releases more oxygen to active skeletal muscles than it does when those muscles rest. Why?

increased T & decreased pH (from heat & acidic wastes generated by active skeletal muscles)

Define gas diffusion.

movement of O2 & CO2 across the blood air barrier bw alveolar air spaces & alveolar capillaries AND across capillary walls bw blood & other tissues

What is inhalation (inspiration)?

moving air into lungs

What is exhalation/expiration?

moving air out of the lungs

Define respiratory rate.

number of breaths per minute

How does the respiratory minute volume differ from alveolar ventilation?

resp minute vol: amt of air moved into & out of resp tract each min alveolar vent: amt of air reaching the alveoli each min bc some air never reaches the alveoli but instead remains in the anatomic dead space, alveolar ventilation is lower than resp min vol

Which ventilates alveoli more effectively: slow, deep breaths or rapid, shallow breaths? Explain why.

slow deep breaths smaller amt of tidal vol of each breath is spent moving air into/out of anatomic dead space of the lungs

Define internal respiration.

the absorption of O2 from blood & the release of CO2 by tissue cells

What are the 3 processes of respiration?

ventilation external respiration internal respiration

When do accessory respiratory muscles become active?

whenever primary respiratory muscles are unable to move enough air to meet the O2 demands of tissues

Identify the primary inspiratory muscles.

diaphragm external intercostal muscles

What pressures determine the direction of airflow within the respiratory tract?

- intrapulmonary P (P inside resp tract) - atmospheric P (P outside of resp tract) air moves from high P to low P

Define Boyle's Law.

At a constant T, the Pof a gas is inversely proportional to its volume.

Explain the relationship among BPG, oxygen, & hemoglobin.

BPG (2,3-biphosphoglycerate) is a compound generated by RBCs during glycolysis that decreases hemoglobin's affinity for oxygen For any partial P of O2, if the [BPG] increases, the amount of oxygen, the amt of O2 released by hemoglobin will increase

How are hypoxia and anoxia different?

Hypoxia: low tissue oxygen levels Anoxia: complete cutoff of oxygen supply.

Define Dalton's Law

In a mixture of gases, the individual gases exert a P proportional to their abundance in the mixture

Describe the movement of the primary inspiratory muscles. What percentage of lung volume do these movement contribute to?

Move to expand thoracic cavity Diaphragm: Contraction = flatten; increases cavity height - 75% of lung vol External intercostals: Lift ribcage & push sternum forward - 25% of lung vol

What physical changes affect the volume of the lungs?

Movement of diaphragm & rib cage

Describe how a vacuum is formed in the lungs.

The lungs get stretched to the larger size of the thorax gases w/in the space spread out to fill the larger space resulting in a decrease in gas P, causing a vacuum that sucks air into the lungs.

Name the various measurable pulmonary volumes.

Tidal volume Expiratory reserve volume Residual volume Inspiratory reserve volume