Respiratory System — HS Anatomy & Physiology practice questions

During an asthma attack, breathing is difficult because:

1. the alveoli fill with blood
2. the trachea is crushed
3. the lungs lose their surfactant
4. the bronchioles narrow and swell

Answer: D — the bronchioles narrow and swell

D) Correct — Muscle tightening and inflammation shrink the airways. A) Is not what happens in asthma. B) The trachea is held open by cartilage rings. C) Is a problem in some premature babies.

What keeps food from entering the trachea when you swallow?

1. The epiglottis
2. The diaphragm
3. The uvula
4. The vocal cords alone

Answer: A — The epiglottis

A) Correct — It folds over the opening of the larynx. B) Drives breathing. C) Helps close off the nasal cavity. D) They help but are not the main cover.

Air flows into the lungs during inhalation because:

1. the lungs pull air in on their own
2. lung pressure rises above outside air pressure
3. chest volume rises and lung pressure drops
4. the alveoli pump air inward

Answer: C — chest volume rises and lung pressure drops

C) Correct — Air moves from higher pressure outside to lower pressure inside. A) Lungs have no muscle; they follow the chest wall. B) Air would flow out. D) Alveoli are passive sacs.

Gas exchange in the lungs happens in the:

1. bronchi
2. alveoli
3. trachea
4. pleura

Answer: B — alveoli

B) Correct — These thin-walled sacs are surrounded by capillaries. A) Are airways that carry air. C) Is the windpipe. D) Is the membrane around the lungs.

What is the path of air into the lungs?

1. Pharynx → larynx → trachea → bronchi → alveoli
2. Larynx → pharynx → bronchi → trachea → alveoli
3. Pharynx → trachea → larynx → alveoli → bronchi
4. Trachea → pharynx → larynx → bronchi → alveoli

Answer: A — Pharynx → larynx → trachea → bronchi → alveoli

A) Correct — Air passes through smaller and smaller tubes. B) Swaps both pairs. C) The larynx sits above the trachea. D) Air enters the pharynx first.

Boyle's law in breathing?

Pressure inverse to volume. Lung expands → pressure drops → air rushes in.

Interactive respiratory system — hover any structure.

The respiratory system moves air in and out of the body for gas exchange (O2 in, CO2 out). Upper airway: nasal cavity, oral cavity, pharynx, larynx. Lower airway: trachea → 2 primary bronchi → 5 secondary bronchi → bronchioles → ~300 million alveoli per lung. Gas exchange happens across the thin (~0.5 μm) alveolar-capillary membrane. The diaphragm contracts (flattens) during inhalation, expanding thoracic volume so air rushes in (Boyle's law).

Alveoli function?

Tiny air sacs. Gas exchange (O2 in, CO2 out) with capillaries.

Surfactant?

A substance made in the alveoli that lowers surface tension so the alveoli do not collapse. Premature babies may lack enough.