Respiratory System

Conchae

• Bony ridges on the lateral walls of the nose

• Causes the air to churn — air can be cleansed, humidified, and warmed

Paranasal sinuses

• Air filled spaces within bone

• Resonating chambers — influence the voice

Mucous membrane

Lining of paranasal sinuses

Lighten the skull

Function of paranasal sinuses

Mucus

What do paranasal sinuses produce

Nares (nostrils)

Where does air enter?

Keratinized stratified squamous epithelium

Epithelium of the nares

Traps debris in the air

What does mucus produced by the nose do?

Moisture from the mucous epithelium

Air is humidified by _____

Blood through the superficial capillary networks under the ME

Air is warmed by ______

Sneeze reflex

• Dislodges the substances from the nasal cavity

• Sensory receptors detect the foreign substances

• Action potentials are conducted along the nerve to the medulla

• Reflex is triggered

Trigeminal nerve to the medulla

(Sneeze reflex)

• Action potentials are conducted along the _____

Uvula and soft palate

During the sneeze reflex, these structures are depressed to allow air coming from the lungs to be directed through the nasal cavity

Pharynx

Passageway for air, food, and water

Larynx

Inferiorly, the pharynx leads to the rest of the respiratory tract via the _____

Esophagus

Passageway of food from pharynx to the stomach

Nasopharynx

Superior part of the pharynx

Soft palate

Floor of the nasopharynx

Uvula

Extension of the soft palate

Nasal cavity

The epithelium of the pharynx is similar and continuous with the _____

Nasopharynx

Auditory tubes open into the _____

Soft palate

During swallowing, this structure elevates to close the nasopharynx and prevent food from entering

Oropharynx

• Extends from the uvula to the epiglottis

• The oral cavity opens into this

• Lined with stratified squamous epithelium — protects against abrasion

• 2 sets of tonsils located near the opening between the mouth and the oropharynx

Oropharynx

The oral cavity opens into the _____

Stratified squamous epithelium

Lining of oropharynx

Laryngopharynx

• Extends from the tip of epiglottis to esophagus

• Food and drinks pass through it

• A small amount of air is usually swallowed with food and drink

Larynx

• Location: Anterior throat and extends from base of the tongue to the trachea

• Passageway for air between the pharynx and trachea

• Consists of outer casing of 9 cartilages

  • cartilages are connected to each other by muscles and ligaments

  • 3 single, 6 paired

• Thyroid cartilage

• Cricoid cartilage

• Epiglottis

What are the unpaired laryngeal cartilages?

Thyroid cartilage

• Largest larynx cartilage

• “Adam’s apple”

• Attached superiorly to the hyoid bone

Cricoid cartilage

• Most inferior larynx cartilage

• Forms the base of the larynx in which other cartilages rest

Epiglottis

• Contains elastic cartilage (laryngeal cartilage)

• Prevents swallowed materials from entering the larynx

• Tips posteriorly during swallowing to cover the opening of the larynx

• Cuneiform

• Corniculate

• Arytenoid

Paired laryngeal cartilages

Posterior aspect of the larynx

Paired laryngeal cartilages are located on each side of the _____

Cuneiform

(Paired laryngeal cartilage)

• Top most

Corniculate

(Paired laryngeal cartilage)

• Middle cartilage

Arytenoid

(Paired laryngeal cartilage)

• Bottom cartilage

Trachea

• “Windpipe”

• Membranous tube attached to the larynx

• Consists of connective tissue and sm reinforced with 16-20 C-shaped hyaline cartilage

• Projects into the mediastinum and divides into the right and left primary bronchi

• Esophagus lies posterior to it

Esophagus

What lies posterior to the trachea?

Mediastinum

The trachea projects into the _____

Left and right bronchi

Primary bronchi

Left bronchi

This bronchi is more horizontal because of the heart

Right bronchus

In which bronchus do foreign substances usually dislodge due to its wider, shorter, and more vertical structure?

• it is also more in direct line with the trachea

Lungs

• Principal organs of respiration

• Cone-shaped with base resting on the diaphragm

• Apex extending above the clavicle

• 3 lobes (right)

• Main bronchi divides to form tracheobronchial tree

Tracheobronchial tree

Main bronchi divides to form the _____

Bronchioles

• Divide numerous times to give rise to terminal bronchioles

  • Terminal bronchioles further subdivide into respiratory bronchioles

    • Respiratory bronchioles divide to form alveolar ducts

      • Each duct opens into an alveoli (2 or more alveolar sacs)

      • 300M alveoli

Respiratory bronchioles

Terminal bronchioles further subdivide into _____

Alveolar ducts

Respiratory bronchioles divide to form _____

Alveoli

Each alveolar duct opens into an _____

Respiratory membrane

• Where gas exchange between the blood and alveoli takes place

• Formed mainly by the walls of the alveoli and the surrounding capillaries

• 6 layers

6

Respiratory membrane has how many layers?

Ventilation

• The process of moving air into and out of the lungs (breathing)

• 2 phases:

  • Inspiration — inhalation

  • Expiration — exhalation

Diaphragm, External intercostal muscles

Muscles of inspiration

Internal intercostal muscles

Muscles of expiration

• Changes in volume results in changes in pressure

• Air flows from an area of higher pressure to an area of lower pressure

2 principles on thoracic volume and pressure changes

• Increased thoracic volume

• Decreased alveolar pressure

What happens to thoracic volume and pressure when you inhale?

• Decreased thoracic volume

• Increased alveolar pressure

What happens to thoracic volume and pressure when you exhale?

Respiratory volumes

• Measures the amount of air movement during different portions of ventilations

  • Tidal volume

  • Inspiratory volume

  • Expiratory reserve volume

  • Residual volume

Tidal volume

• Volume of inspired or expired air with each breath

• 500 mL

Inspiratory reserve volume

• Amount of air that can be inspired forcefully beyond the resting tidal volume

• 3000 mL

Expiratory reserve volume

• Amount of air that can be expired forcefully beyond the resting tidal volume

• 1100 mL

Residual volume

• Volume of air still remaining in the respiratory passages and lungs after maximum expiration

• 1200 mL

500 mL

Tidal volume

3000 mL

Inspiratory reserve volume

1100 mL

Expiratory reserve volume

1200 mL

Residual volume

Functional residual capacity

• ERV + RV

• Amount of air remaining in the lungs at the end of normal expiration

• 2300 mL at rest

Inspiratory capacity

• Tidal volume + IRV

• Amount of air a person can inspire maximally after normal expiration

• 3500 mL at rest

Vital capacity

• IRV + TV + ERV

• Maximum volume of air that a person can expel from the respiratory tract after maximum inspiration

• 4600 mL

Total lung capacity

• IRV + ERV + TV + RV

• 5800 mL

2300 mL at rest

Functional residual capacity

3500 mL at rest

Inspiratory capacity

4600 mL

Vital capacity

5800 mL

Total lung capacity