Respiration

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Questions and Answers

What is the primary function of the coarse hair in the vestibule of the nasal cavity?

to trap foreign particles (correct)

to warm and humidify the incoming air

to detect odor molecules

to produce nasal mucus

What bones form the bony portion of the nasal septum?

Sphenoid and palatine bones

Maxillary and zygomatic bones

Frontal and lacrimal bones

Perpendicular plate of ethmoid and vomer bones (correct)

What is the function of the turbulence created by the conchae in the nasal cavity?

to increase the velocity of airflow

to reduce the humidity of the incoming air

to decrease the temperature of the incoming air

to facilitate the filtration of small air-borne particles (correct)

What is the boundary between the superior nasopharynx and the rest of the pharynx?

The soft palate Signup and view all the answers

What type of bones form the floor of the nasal cavity?

Maxillary and palatine bones Signup and view all the answers

What is the function of the nasal cavity in terms of air processing?

to filter and warm the air Signup and view all the answers

What is the name of the narrow grooves through which air flows between adjacent conchae?

Meatuses Signup and view all the answers

Where does the nasal cavity open into?

Nasopharynx Signup and view all the answers

What is the primary function of the nasal cavity in the respiratory system?

To filter, warm, and humidify the air Signup and view all the answers

Which of the following structures is NOT part of the upper respiratory system?

Lungs Signup and view all the answers

What type of epithelium lines the respiratory tract?

Pseudostratified, ciliated, columnar epithelium Signup and view all the answers

What is the function of the goblet cells in the respiratory epithelium?

To produce a sticky mucus that traps debris Signup and view all the answers

Where do the cilia in the nasal cavity sweep debris and microorganisms towards?

The pharynx Signup and view all the answers

What happens to the air by the time it reaches the lung alveoli?

Most foreign particles and pathogens have been removed Signup and view all the answers

What is the function of the pharynx in the respiratory system?

To swallow debris and microorganisms trapped in mucus Signup and view all the answers

What is the purpose of the respiratory epithelium's filtering, warming, and humidification of the air?

To prepare the air for exchange with the lungs Signup and view all the answers

What is the function of the ventricular folds?

To prevent foreign objects from entering the glottis Signup and view all the answers

What is the diameter of the trachea?

2.5cm Signup and view all the answers

What is the purpose of the tracheal cartilages?

To stiffen tracheal walls and protect the airway Signup and view all the answers

What is the shape of each tracheal cartilage?

C-shaped Signup and view all the answers

What is the function of the trachealis?

To connect the ends of each tracheal cartilage Signup and view all the answers

What is the significance of the carina?

It marks the line of separation between the right and left primary bronchi Signup and view all the answers

What is the purpose of the hilum of the lung?

Access for entry of pulmonary vessels, nerves, and bronchi Signup and view all the answers

What is the largest subdivision of a lobe?

Bronchopulmonary segment Signup and view all the answers

What is the function of type II cells in the alveoli?

To secrete surfactant Signup and view all the answers

Which artery supplies the lung with nutrients?

Bronchial artery Signup and view all the answers

What is the name of the passageways that connect respiratory bronchioles to alveoli?

Alveolar ducts Signup and view all the answers

How many alveoli are present in each lung?

150 million Signup and view all the answers

What is the name of the veins that drain lung tissues?

Bronchial veins Signup and view all the answers

Where does the right bronchial artery arise from?

3rd posterior intercostal artery Signup and view all the answers

What is the name of the lymphatic plexus that drains lung tissue and visceral pleura?

Subpleural lymphatic plexus Signup and view all the answers

What is the function of the pulmonary ligament?

To provide space for pulmonary veins to expand during increased venous return Signup and view all the answers

What is the name of the median partition that separates the right and left pleural cavities?

Mediastinum Signup and view all the answers

Which muscle contracts to increase the volume of the thoracic cavity during inspiration?

Diaphragm Signup and view all the answers

What is the term for the physical movement of air into and out of the bronchial tree?

Pulmonary ventilation Signup and view all the answers

What is the outer layer of the pleural sac that invaginates from the medial side?

Parietal pleura Signup and view all the answers

What is the shape of each lung?

A blunt cone Signup and view all the answers

What is the term for the space between the two layers of the pleural sac?

Potential space Signup and view all the answers

Which of the following muscles is not involved in inspiration?

Rectus abdominis Signup and view all the answers

Study Notes

Functions of Respiratory System

Provides an extensive area for gas exchange between air and circulating blood
Moves air to and from the exchange surfaces of the lungs
Protects respiratory surfaces from dehydration, temperature changes, and other environmental variations
Defends the respiratory system and other tissues from invasion by pathogenic microorganisms
Produces sounds involved in speaking, singing, or non-verbal communication
Assists in the regulation of blood volume, blood pressure, and the control of body fluid pH

Organization of Respiratory System

Upper respiratory system: nose, nasal cavity, paranasal sinuses, pharynx
Lower respiratory system: larynx, trachea, bronchi, lungs
Filters, warms, and humidifies air

Respiratory Tract

Consists of airways that carry air to and from exchange surfaces of lungs
Conducting portion: extends from the entrance to the nasal cavity to the smallest bronchioles of the lungs
Respiratory portion: includes respiratory bronchioles and air sacs (alveoli)
By the time air reaches lung alveoli, most foreign particles and pathogens have been removed due to filtering, warming, and humidification of air

Respiratory Epithelium

Consists of pseudostratified, ciliated, columnar epithelium with goblet cells
Lines the entire respiratory tract except for the finest conducting portions and alveoli
Goblet cells and mucus glands beneath the epithelium produce a sticky mucus that bathes exposed surfaces

Upper Respiratory System

Nose and nasal cavity: primary passageway for air entering the respiratory system
Air enters paired external nares that open into the nasal cavity
Vestibule: portion of the nasal cavity contained within the flexible tissues of the external nose
Vestibule contains coarse hair that traps foreign particles

Nasal Cavity

Nasal septum: divides the cavity into right and left halves
Bony portion of the nasal septum is formed by the perpendicular plate of the ethmoid and vomer
Anterior portion of the septum is formed by hyaline cartilage
Bones of the nasal cavity: maxillary, nasal, frontal, ethmoid, and sphenoid bones
Lateral and superior walls of the nasal cavity are formed by these bones
Nasal cavity: lateral wall projecting from the lateral wall are superior, middle, and inferior conchae
Air flows between adjacent conchae through superior, middle, or inferior meatuses (narrow grooves)
Incoming air bounces off conchal surfaces, creating turbulence, which causes small airborne particles to come into contact with mucus that lines the cavity
Turbulence allows extra time for humidifying and warming incoming air

Tertiary Bronchi

Each lobe of the lungs can be divided into smaller units – bronchopulmonary segment
Separated from adjacent segments by septa
Supplied by segmental bronchus and tertiary branch of the pulmonary artery
Drained by intersegmental parts of the pulmonary veins
Surgically resectable

Bronchioles

Respiratory bronchioles connected to alveoli along regions called alveolar ducts
Passageways end at alveolar sacs
Each lung has 150 million alveoli – giving the lung a spongy appearance

Alveolus and Respiratory Membrane

Type 1 cells: squamous epithelial cells
Type II cells: septal or surfactant cells
Type II cells secrete surfactant, which coats the inner surface of each alveolus, reducing surface tension in the fluid coating the alveolar surface
Without surfactant, alveoli would collapse

Arterial Supply of Lungs

Bronchial arteries arise from the systemic circulation and supply the lung and its associated tissues with nutrients
Left bronchial artery arises from the descending thoracic aorta; right bronchial artery arises from the 3rd posterior intercostal artery

Venous Drainage of Lungs

Bronchial veins drain lung tissues
Right bronchial vein drains into the azygos vein; left bronchial vein drains into the accessory hemiazygos vein or left superior intercostal vein

Lymphatic System of Lungs

Superficial lymphatics of the lung
Bronchopulmonary (hilar) lymph nodes

Larynx

Ventricular and vocal ligaments covered by folds of laryngeal epithelium that project into the glottis
Ventricular ligaments lie within the superior pair of folds – ventricular folds (inelastic and help prevent foreign objects from entering the glottis and provide protection for more delicate vocal folds)

The Trachea

Trachea is a tough, flexible tube with a diameter of 2.5cm and a length of 11cm
Begins anterior to the C6 vertebra in a ligamentous attachment to the cricoid cartilage
Ends in the mediastinum at the level of the T5 vertebra
Branches to form the right and left primary bronchi
Lining of the trachea consists of respiratory epithelium overlying a layer of looser connective tissue (lamina propria)
Trachea contains tracheal cartilages
Each tracheal cartilage is bound to neighboring cartilages by elastic annular ligaments
Tracheal cartilages stiffen the tracheal walls and protect the airway
Also prevents its collapse or overexpansion as pressures change in the respiratory system

Primary Bronchi

Right and left primary bronchi
Carina marks the line of separation between the two bronchi
Has cartilaginous C-shaped supporting rings
Right primary bronchus – larger diameter than the left and descends towards the lung in a steeper angle
Hilum of the lung: access for the entry of pulmonary vessels, nerves, and bronchi

The Pleura

Pleura is a serous membrane lined by mesothelium
Two pleural sacs – one on either side of the mediastinum
Pleural sac invaginated from the medial side by the lung, so it has an outer layer (parietal pleura) and an inner layer (visceral pleura)
Two layers are continuous with each other around the hilum of the lung and enclose between them a potential space (pleural cavity)

Pulmonary Pleura

Covers the surfaces and fissures of the lung, except at the hilum and along the attachment of the pulmonary ligament, where it is continuous with the parietal pleura
Firmly adherent to the lung and cannot be removed from it

Parietal Pleura

Lines the pulmonary cavities and thus adheres to the thoracic wall, mediastinum, and diaphragm
Has four parts

Thoracic Cavity

Cavity of the thorax contains the right and left pleural cavities, completely invaginated and occupied by the lungs
Right and left pleural cavities are separated by a thick median partition called the mediastinum
Heart lies in the mediastinum

Pulmonary Ligament

Definition: Parietal pleura surrounding the root of the lung, extending downward beyond the root as a fold
Function: provides space into which pulmonary veins can expand during increased venous return; lung root also descends into it with the descent of the diaphragm

Pulmonary Ventilation

Refers to the physical movement of air into and out of the bronchial tree
Respiratory muscles: contraction of the diaphragm increases the volume of the thoracic cavity, drawing air into the lungs
Inspiration: elevate ribs, external and internal intercostal, SCM, pectoralis minor, scalenes, and serratus anterior
Expiration: depress ribs, transversus thoracis, abdominal obliques, and rectus abdominis

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