Lower Respiratory System

(Lower Respiratory System)

•Just behind the heart, the trachea divides into 2
bronchi (singular:
bronchus)

•The bronchi branch into
bronchioles, which are
smaller tubes.

•The lungs are
covered with a thin
membrane called
the pleura.

•The pleural space
contains pleural
fluid, which reduces
friction between
the lungs and the
rest of the thoracic
cavity.

cardiac notch

Inferior lobe

Superior lobe

Superior lobe

Inferior lobe

Middle lobe

Apex

Base

•The right lung has 3 lobes and the left lung has 2.

•The left lung also has an
indentation for the heart, called the cardiac notch.

•Smaller and smaller tubes continue to branch off the
bronchioles until they reach tiny air sacs called alveoli.

•Alveoli are clustered in grape-like bunches of tiny
bubbles.

•Each alveolus is surrounded by capillaries.

•The thin-walled alveoli and the surrounding capillaries make up
the respiratory zone, which is the site of gas exchange within the respiratory system.

•A respiratory membrane is found between the capillary and each alveolus.

•Alveolar macrophages move in and out of the alveoli collecting any remaining bacteria or particulates.

•The trachea leads to the
bronchi, then bronchioles, and finally to the lungs. The lungs are made of alveoli closely attached to capillaries, which make up the respiratory zone.

Multiple Select

What are the structures of the lower respiratory tract?

• Bronchi, Bronchioles,

• Pharynx
• Larynx
• Esophagus
• Trachea, Alveoli

Multiple Choice

What is the purpose of the pleural
fluid?

• To regulate blood flow in the lungs
• To provide nutrients to the heart
• To support the structure of the ribs
• To reduce friction between the two layers of pleura surrounding the lungs

Multiple Choice

The left lung has ___ lobes while the right lung has ___ lobes.

• 2, 2
• 1, 4
• 2, 3
• 3, 2

Multiple Choice

How do the capillaries and alveoli work together?

• Oxygen from the alveoli diffuses into the capillaries, while carbon dioxide from the capillaries diffuses into the alveoli.
• Carbon dioxide diffuses from the alveoli into the capillaries, while oxygen diffuses from the capillaries into the alveoli.
• The capillaries absorb oxygen from the alveoli and release carbon dioxide into them.
• Alveoli release oxygen into the bloodstream, while capillaries release carbon dioxide into the lungs.

Multiple Select

Where in the respiratory system does gas exchange happen?

• Pharynx
• Trachea
• Bronchi
• Alveoli
• respiratory zone

Multiple Choice

What is the importance of Alveolar macrophages?

• Alveolar macrophages have no role in lung health
• Alveolar macrophages are only important for producing mucus in the lungs
• Alveolar macrophages are primarily responsible for oxygen exchange in the lungs
• Alveolar macrophages are important for defending against inhaled pathogens and maintaining lung health.

•External respiration occurs when gases are
exchanged between the pulmonary blood
vessels and the alveoli.

•This process is preceded by ventilation, also known as breathing.

•Internal respiration occurs when the blood exchanges gases with the body tissues.

•External respiration occurs in the lungs while
internal respiration occurs throughout the
body.

•The diaphragm is a large, flat muscle connected to the ribs at the bottom of the chest cavity. The
external intercostals are muscles found between
each rib of the rib cage.

•By contracting the diaphragm and intercostals, the rib cage expands, decreasing the pressure inside the lungs, causing air to rush in.

•This is called inspiration or inhalation.

•Relaxing theses muscles causes the rib cage to decrease in size, increasing the pressure in the lungs and causing air to rush out.

•This is called expiration or exhalation.

• Tidal volume= the amount of air that is exchanged by the lungs at rest

• Inspiratory reserve volume= the additional amount of air that can be

inhaled consciously

• Expiratory reserve volume= the additional amount of air that can be exhaled consciously

• Residual volume= the amount of air remaining in lungs after a forced exhalation

• Vital capacity= amount of air someone can consciously exchange with the environment (inhaling and exhaling)

• Total lung capacity= vital capacity + residual volume (about 6 liters for adult men, 10% less for adult females)

•External respiration is
preceded by breathing.
Muscle movements lead to
volume and pressure changes,
causing air to move in and out.
Total lung capacity can be
divided into several partial
volumes.

Match

Match the following

• tidal volume

• inspiratory reserve volume

• expiratory reserve volume

• residual volume

• total lung capacity

volume of air inhaled and exhaled during normal breathing

additional air that can be inhaled after a normal inhalation

volume of air that can be exhaled after a normal exhalation

air remaining in the lungs after a forced exhalation

maximum amount of air the lungs can hold

• volume of air inhaled and exhaled during normal breathing

• additional air that can be inhaled after a normal inhalation

• volume of air that can be exhaled after a normal exhalation

• air remaining in the lungs after a forced exhalation

• maximum amount of air the lungs can hold

Multiple Choice

What muscles help with inhalation?

• Biceps and triceps
• Hamstrings and quadriceps
• Pectoral and deltoid muscles
• Diaphragm and external intercostal muscles

Multiple Choice

What is the difference between internal and external respiration?

• Internal respiration is the process of breathing in, while external respiration is the process of breathing out.
• Internal respiration involves the exchange of gases in the digestive system, while external respiration involves the exchange of gases in the circulatory system.
• Internal respiration occurs in the lungs, while external respiration occurs in the heart.
• Internal respiration occurs between blood and body tissues, while external respiration occurs between lungs and blood.