ANAPHY: U11.3 Respiratory System (Lower Respiratory Tract)

Trachea (Windpipe)

Structure that allows air flow into lungs

Larynx to main bronchi

What does the trachea connect?

C-Shaped Hyaline Cartilage (Tracheal Ring)

What does the trachea have for support?

Smooth Muscle

What regulates the diameter of trachea by contracting and aids in coughing?

Mucous Membrane with Goblet Cells & Cilia

What is the trachea lined by?

Carina

End-point of trachea before it branches into primary bronchi (cartilage ridge that indicates the end of the trachea before it bifurcates)

Two Main Bronchi

What does the trachea divide to form?

Lobar Bronchi, Segmental Bronchi, Bronchioles, Terminal Bronchioles

What do the Main Bronchi further divide to?

Trachea to Terminal Bronchiole

What is the passageway for air?

Terminal Bronchiole

What is lined by ciliated simple cuboidal epithelium to help remove inspired debris?

Ciliated Simple Cuboidal Epithelium

What is the Terminal Bronchiole lined by helping remove inspired debris?

Bronchodilation & Bronchoconstriction

What are bronchi and bronchioles capable of doing?

Smooth Muscle

What enables the bronchi and bronchioles to be capable of bronchodilation and bronchoconstriction?

Ventilation

What does the conducting zone (nose, pharynx, larynx, trachea, bronchi, and most bronchioles) perform only?

Gas Exchange

What does respiration involve?

Alveoli

Small, air-filled chambers where the air and blood come into close contact for exchange of gases

Respiratory bronchioles, alveolar ducts, and alveolar sacs

What do terminal bronchioles divide to form?

Elastic Fibers

What does alveoli contain that allow expansion during inspiration and recoil during expiration?

Simple Squamous Epithelium & Surfactant-Secreting Cells

2 Types of Cells that Form the Alveolar Wall

Simple Squamous Epithelium

One of the types of cells that form the alveolar wall; allows gas exchange between alveolar air and blood

90%

Simple Squamous Epithelium make up how much percent of alveolar cells?

Gas Exchange between Alveolar Air & Blood

What does the simple squamous epithelium (a type of alveolar cell) enable?

Surfactant-Secreting Cells

One of the types of cells that form the alveolar wall; produce surfactant which make alveolar expansion during inspiration easier

Surfactant

What does a specific alveolar cell secrete to make alveolar expansion during inspiration easier?

Thoracic Vertebrae, Ribs, Costal Cartilages, Sternum, Associated Muscles

5 Components of the Thoracic Wall

Thoracic Cavity

Space enclosed by the thoracic wall

Diaphragm

Sheet of skeletal muscle that separates thoracic cavity from abdominal cavity

Diaphragm, External Intercostals, Pectoralis Minor, Scalene Muscles

4 Muscles of Inspiration

Internal Intercostals, Transverse Thoracis, (assistance from) Abdominal Muscles

3 Muscles of Expiration

Phrenic Nerve

What nerve does the diaphragm have that is present during inhalaition?

Lungs

Primary organs of respiration with the base of this in contact with diaphragm and the apex is above the clavicle

Diaphragm

What is the base of the lung in contact with?

Above the clavicle

Where is the apex of the lung located?

3

How many lobes does the right lung have?

2

How many lobes does the left lung have?

Bronchopulmonary Segments

What are the lobes of the lungs further subdivided into?

Hilum

Indentation of medial surface where, main bronchus, blood vessels, nerves, lymphatic vessels enter and exit

Main Bronchus, Blood Vessels, Nerves, Lymphatic Vessels

What enter the hilum of the lung?

Cardiac Notch

Medial indentation on left lung as space for the heart to lie between the lungs

Pulmonary Arteries

What carries deoxygenated blood to the lungs?

Pulmonary Veins

What carries oxygenated blood away from the lungs?

Lymphatic Supplies

Superficial lymphatic vessels and deep lymphatic vessels drain lymph from bronchi and lungs

Pleura

Serous membrane that lines the two pleural cavities; parietal pleura (thoracic cavity) and visceral pleura covers lung surface

Parietal & Visceral Pleura

2 Types of Pleura

Parietal Pleura

Type of pleura; lines thoracic cavity

Visceral Pleura

Type of pleura; covers lung surface

Ventilation

Movement of air into and out of lungs

1. Contraction of diaphragm increases thoracic volume

2. Muscles elevate ribs and increase thoracic volume or depress the ribs and reduce thoracic volume

Mechanism of the Muscles of Respiration

Air moves from areas of higher pressure to areas of lower pressure

Relationship between air and pressure

Atmospheric pressure is greater than air pressure in the alveoli, so air flows through trachea and bronchi to alveoli

During inspiration, what is the relationship between the atmospheric pressure to alveolar pressure?

Spirometry

Process of measuring volumes of air that move into and out of respiratory system

Spirometer

Instrument that measure the pulmonary volumes and capacities

1. Tidal Volume

2. Expired Reserve Volume

3. Residual Volume

4. Inspiratory Reserve Volume

4 Types of Pulmonary/Respiratory Volumes

Tidal Volume

One of the types of Pulmonary/Respiratory Volumes; the normal volume of air inspired and expired with each beat

500 mL

What is the normal Tidal Volume?

Expired Reserve Volume

One of the types of Pulmonary/Respiratory Volumes; amount of air that can be forcefully expired after a normal expiration

1100 mL

What is the normal Expired Reserve Volume?

Residual Volume

One of the types of Pulmonary/Respiratory Volumes; volume of air remaining in respiratory passages and lungs after the most forceful expiration (1200)

1200 mL

What is the normal Residual Volume?

Inspiratory Reserve Volume

One of the types of Pulmonary/Respiratory Volumes; amount of air that can be inspired forcefully after a normal inspiration (3000 mL)

3000 mL

What is the normal inspiratory reserve volume?

Pulmonary/Respiratory Capacities

Sum of two or more pulmonary volumes

1. Inspiratory Capacity

2. Vital Capacity

3. Functional Residual Capacity

4. Total Lung Capacity

4 Types of Pulmonary/Respiratory Capacities

Inspiratory Capacity

One type of Pulmonary/Respiratory Capacities; Tidal Volume (500 mL) + IRV (3000 mL) = 3500 mL at rest

Tidal Volume (500 mL) + IRV (3000 mL)

What adds up to produce Inspiratory Capacity (3500 mL)?

Vital Capacity

One type of Pulmonary/Respiratory Capacities; IRV (3000 mL) + Tidal Volume (500 mL) + ERV (1100 mL) = 4600 mL

IRV (3000 mL) + Tidal Volume (500 mL) + ERV (1100 mL)

What adds up to Vital Capacity (4600 mL)?

Functional Residual Capacity

One type of Pulmonary/Respiratory Capacities; Expired Reserve Volume (1100 mL) plus residual volume (1200 mL); volume remaining in the lungs after normal expiration (2,300ml).

ERV (1100 mL) + Residual Volume (1200 mL)

What adds up to Functional Residual Capacity (2600 mL)?

Total Lung Capacity

One type of Pulmonary/Respiratory Capacities; sum of IRV (3000 mL), ERV (1100 mL), tidal volume (500 mL) and residual volume (1200 mL) = 5800 mL

IRV (1200 mL), ERV (1100 mL), tidal volume (500 mL), residual volume (1200 mL)

What adds up to Total Lung Capacity (5800 mL)?

Tidal Volume

Increases with increased activity which causes a decrease in the inspiratory and expiratory reserve volumes

Gender, age, body size and physical conditions

4 other factors that can cause variations in lung volumes and capacities in individuals

Alveolar Ventilation

Measurement of volume of air available for gas exchange per minute

Dead Space

Remaining areas where no gas exchange

Anatomical & Physiological Dead Space

2 Types of Dead Space

Anatomical Dead Space

Type of dead space; all areas in URT and LRT until terminal bronchioles

Physiological Dead Space

Type of dead space; combination of anatomical dead space & volume of any alveoli with lower than normal gas exchange

Atmospheric Air

A mixture of gases in different amount and each gas is measured as partial pressure at sea level

760 mmHg with 21% O2

What is the value of atmospheric pressure?

Lower, causing lower O2 to enter the lungs

What is the total atmospheric pressure at higher altitudes compared to at sea level?

Inspiration & Expiration

What does one respiratory cycle or breathing involve?

1. Alveolar pressure is lower than atmospheric pressure and air flows in.

2. Pleural cavity pressure is lower than alveoli pressure and atmospheric pressure (negative pressure)

3. Thorax expands and allows the lungs to expand

4. Diaphragm contracts and moves downward

4 Events of Inspiration

1. Alveolar pressure is greater than atmospheric pressure and air moves out.

2. Pleural cavity pressure remains in negative pressure.

3. Thorax recoils to normal size, as tension decrease.

4. Diaphragm relaxes and aid in lung recoil

4 Events of Expiration

Elastic Recoil

Causes lung recoils after being stretched

Surfactant

Prevents complete collapse of the lungs and reduces surface tension

An increase in respiratory membrane thickness decreases gas diffusion

How does respiratory membrane thickness affect rate of gas diffusion?

4 subunits

How many subunits does hemoglobin have?

4 O2

How many O2 bind to each hemoglobin?

98.5%

Percentage of O2 transported bound to hemoglobin?

1.5%

Percentage of O2 transported found in plasma?

7%

Percentage of CO2 that dissolves directly in plasma?

23%

Percentage of CO2 that is bound to hemoglobin?

More CO2 can bind to hemoglobin

What occurs to the CO2 when less O2 is bound to hemoglobin?

70%

Percentage of CO2 converted into bicarbonate?

CO2 gets catalyzed by carbonic anhydrase —> Carbonic Acid (H2CO3) —> HCO3 & H ion

How does CO2 get converted into bicarbonate?

Chemoreceptors in the Blood Vessels

Aortic bodies and carotid bodies respond to changes in pH, PO2 and PCO2

pH, PO2, PCO2

Changes in what do Chemoreceptors in the Blood Vessels respond to?

100%

If hemoglobin carries 4 O2 molecules, what is the percent of saturation?

More CO2 binds to Hemoglobin

If partial O2 levels decreases, what occurs in regards to CO2?