10 - other functions of respi

What are the main non-respiratory (other) functions of the respiratory system

Defense, metabolic/endocrine activity, thermoregulation, water balance, blood reservoir function, acid-base regulation, vocalization, olfaction, reflexes, and filtration of blood

What structures in the upper respiratory tract filter incoming air

Nasal passages and turbinates

What types of particles are removed by nasal filtration

Dust, microorganisms, and foreign particles

What is mucociliary clearance

A defense mechanism where mucus traps particles and cilia move them toward the pharynx for removal

Which cells produce mucus in the airways

Goblet cells

What is the role of ciliated epithelial cells in the respiratory tract

They beat rhythmically to move mucus and trapped particles upward

Where are trapped particles transported by the mucociliary escalator

To the pharynx where they are swallowed or expelled

What reflex clears irritants from the lower respiratory tract

Cough reflex

What reflex clears irritants from the upper respiratory tract

Sneezing

What immune cells are primarily responsible for phagocytosis in the alveoli

Alveolar macrophages

What is BALT in the respiratory system

Bronchus-associated lymphoid tissue involved in immune defense

What type of immunoglobulin is commonly secreted in the respiratory tract

IgA

What important enzyme is found in pulmonary endothelial cells

Angiotensin-converting enzyme (ACE)

What is the function of ACE in the lungs

Converts angiotensin I to angiotensin II

Why is angiotensin II important

It regulates blood pressure through vasoconstriction

Name some substances inactivated or removed by the lungs

Bradykinin, serotonin, prostaglandins, and some drugs/toxins

Which cells produce surfactant in the lungs

Type II pneumocytes

What is the function of surfactant

Reduces surface tension and prevents alveolar collapse

What condition is prevented by surfactant in the lungs

Atelectasis

How does the respiratory system contribute to thermoregulation

By evaporative heat loss through breathing

What is panting

Rapid shallow breathing that increases evaporative heat loss

Why does panting not significantly alter CO₂ levels

Because breaths are shallow and mainly ventilate dead space

Which animals rely heavily on panting for thermoregulation

Dogs

Which animals rely less on panting and more on sweating

Horses

How does the respiratory system help maintain water balance

By humidifying inspired air and losing water during expiration

What happens to water loss when respiratory rate increases

Water loss increases

What role does the pulmonary circulation play in blood volume regulation

It acts as a blood reservoir

When can the lungs release stored blood into circulation

During exercise or hemodynamic changes

How does the respiratory system regulate acid-base balance

By controlling CO₂ levels in the blood

What happens to blood pH when ventilation increases

CO₂ decreases and pH increases (respiratory alkalosis)

What happens to blood pH when ventilation decreases

CO₂ increases and pH decreases (respiratory acidosis)

What chemical reaction links CO₂ to pH regulation

CO₂ + H₂O forms carbonic acid which dissociates into H⁺ and bicarbonate

How does the respiratory system contribute to vocalization

Air passing through the larynx produces sound

What is the role of the respiratory system in olfaction

It delivers odorants to the olfactory epithelium

Which animals have a highly developed sense of smell

Dogs

What are stretch receptors in the lungs responsible for

Regulating breathing via reflexes like the Hering–Breuer reflex

What do irritant receptors detect in the respiratory system

Harmful particles or gases

What are J (juxtacapillary) receptors sensitive to

Changes in pulmonary capillary pressure and interstitial fluid

What is the function of pulmonary capillaries in filtering blood

They trap small emboli such as clots, fat, and air bubbles

Why is filtration of emboli by the lungs important

It prevents them from entering systemic circulation

Why are horses obligate nasal breathers

Their anatomy restricts breathing to the nasal passages only

How does vagal sensitivity affect respiration in ruminants

It enhances airway reflexes and responsiveness

Why is the mucociliary escalator important for lung health

It continuously removes debris and pathogens from airways