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Anatomy of the

Respiratory SystemIncludes Physiology

Anatomy & Physiology: HonorsTurner College & Career High School

2018

Respiratory System

Upper Respiratory Tract

Conducting passageways carrying air

to and from the alveoli.

◦ Upper respiratory passages filter and

humidify incoming air.

Nasal Cavity

Larynx

Pharynx

Nasopharynx

Oropharynx

Laryngopharynx

Lower Respiratory Tract

Conducting passageways carrying air to and from the alveoli.

◦ Lower passageways include delicate conduction passages and alveolar exchange surfaces.

Trachea

Lungs

Bronchi

Bronchioles

Alveoli

Diaphragm

Respiratory System Pathway

Nasal Cavity (or oral cavity)

Pharynx

Trachea

Primary bronchi (left or right)

Secondary bronchi

Tertiary bronchi

Bronchioles

Alveoli

Nasal Cavity Functions

Provides an airway for respiration.

Moistens and warms entering air.

Filters and cleans inspired air.

Resonating chamber for speech.

Detects odors in the airstream.

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Nasal Cavity Anatomy Nasal Cavity Anatomy

Vibrissae (guard hairs) – stiff hairs that filter large

particles from the air.

Nasal cilia – hair-like projections that propel

trapped particles towards the throat for digestion

by digestive enzymes.

Rich supply of capillaries warm the inspired air

Nasal conchae – folds in the mucous membrane

that increase air turbulence and ensures that most

air contacts the mucous membranes.

Nasal Cavity Anatomy

Olfactory mucosa – mucous membranes that

contain smell receptors.

Respiratory mucosa – pseudo-stratified ciliated

columnar epithelium containing goblet cells that

secrete mucus.

◦ Mucus

◦ Stickiness traps inhaled particles

◦ Lysozyme kills bacteria

Lymphocytes & IgA antibodies protect against

bacteria.

Sinuses

Upper Respiratory

Three regions of the pharynx:

• Nasopharynx – air passage (pseudostratified

columnar epithelium).

• Oropharynx – passageway for air, food, and drink

(stratified squamous epithelium).

• Laryngopharynx –

passageway for air, food,

and drink (stratified

squamous epithelium).

Upper Respiratory

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Larynx Anatomy

• Nine c-rings of hyaline cartilage form the framework of the larynx.

• Muscular walls aid in voice production and the swallowing reflex.

• Glottis – the superior opening of the larynx.

• Epiglottis – prevents food and drink from entering airway when swallowing.

• False vocal cords – aid in closing the glottis when swallowing.

• True vocal cords – produce sound when air passes between them.

• The shorter and thinner these membranes are, the faster air moves over them – produces high pitched sounds.

• The longer and thicker these membranes are, the slower air moves over them – produces low pitched sounds.

Larynx

Larynx

Functions

1. Keeps food and drink out of the airway.

2. Sound production.

3. Acts as a sphincter during abdominal straining (ex.

during defecation and heavy lifting).

Trachea Anatomy

Functions

1. Air passageway.

2. Cleans, warms, and moistens incoming air.

3. Selected anatomical features:

• Rings of hyaline cartilage – reinforce the trachea

and keep it from collapsing when you inhale.

• Ciliated pseudostratified epithelium – traps

inhaled debris and propels mucus up to the

pharynx where it is swallowed.

Trachea Lung Anatomy

Function - Solely an air passageway.

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Lung Segmental Anatomy Lung Features1. Left and right primary bronchi

branch off from trachea. 2. Once the left and right primary

bronchi enter the lungs they are subdivided into smaller tubes: ◦ Secondary bronchi (one for each

lobe) → tertiary bronchi →bronchioles → terminal bronchioles → respiratory bronchioles →alveolar ducts → alveolar sacs.

3. Alveolar sacs are clusters of alveoli:◦ Alveoli are the site of gas

exchange.◦ Surfactant prevents from

collapsing due to tension◦ Other tissue types present in the

alveoli: Smooth muscle rings aid in resistance

to air flow Elastic connective tissue fibers aid in

expelling air from the lungs.

Normal Lungs Cystic Fibrosis

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Asthmatic Lung Smoker’s Lungs

Lung Cancer

Physiology of the

Respiratory System

Anatomy & Physiology: HonorsTurner College & Career High School

2018

Part 2

Inhalation & Exhalation Inhalation & Exhalation

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Respiration Physiology

Respiration Physiology

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Pulmonary Volumes

Values determined by using a spirometer:

◦ Tidal volume – amount of air inhaled or exhaled with each breath under resting conditions.

◦ Inspiratory reserve volume – amount of air that can be inhaled during forced breathing in addition to resting tidal volume.

◦ Expiratory reserve volume – amount of air that can be exhaled during forced breathing in addition to tidal volume.

◦ Residual volume – Amount of air remaining in

the lungs after a forced exhalation.

Pulmonary Volumes

Values determined by adding two or more of the

respiratory volumes:

◦ Vital capacity – maximum amount of air that can be expired after taking the deepest breath possible (VC = TV + IRV + ERV).

◦ Inspiratory capacity – maximum volume of air that can be inhaled following exhalation of resting tidal volume (IC = TV + IRV).

◦ Functional residual capacity – volume of air remaining in the lungs following exhalation of resting volume (FRC = ERV + RV).

◦ Total lung capacity – total volume of air that the lungs can hold (TLC = VC + RV).

Pulmonary Volumes

Dead space:

◦ Anatomical dead space – areas of the

conducting zone that contains air that never

contributes to the gas exchange in the alveoli.

◦ Alveolar dead space – alveoli that are collapsed

or obstructed and are not able to participate in

gas exchange.

Spirogram

Pulmonary Gas Exchange Pulmonary Gas Exchange

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Hemoglobin

• Quaternary protein.

• Fe centered heme groups.

• O2 binds to heme group.

• CO2 binds to amine groups.

Systemic Gas Exchange

Regulation of Breathing

Your respiratory rate changes.

◦ Active - your respiratory rate goes up.

◦ Less active, or sleeping - the rate goes down.

Even though the respiratory muscles are voluntary,

you can't consciously control them when you're

sleeping.

So, how is respiratory rate altered & how is

respiration controlled when you're not consciously

thinking about respiration?

Regulation of Breathing

The rhythmicity center of the medulla:

◦ Controls automatic breathing.

◦ Consists of interacting neurons that fire either

during inspiration (I neurons) or expiration (E

neurons). I neurons - stimulate neurons that innervate respiratory

muscles (to bring about inspiration)

E neurons - inhibit I neurons (to 'shut down' the I neurons &

bring about expiration).

◦ Apneustic center (located in the pons) -

stimulate I neurons to promote inspiration.

◦ Pneumotaxic center (located in the pons) -

inhibits apneustic center & inhibits inspiration

(promotes expiration).

Regulation of Breathing Patterns of Breathing

Apnea – Temporary cessation of breathing (one or more

skipped breaths).

Dyspnea – Labored, gasping breathing; shortness of breath.

Eupnea – Normal, relaxed, quiet breathing.

Hyperpnea – Increased rate and depth of breathing in

response to exercise, pain, or other conditions.

Hyperventilation – Increased pulmonary ventilation in

excess of metabolic demand.

Hypoventilation – Reduced pulmonary ventilation.

Orthopnea – Dyspnea that occurs when a person is lying

down.

Respiratory arrest – Permanent cessation of breathing.

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Clinical Disorders & Diseases

Hypoxia – deficiency of oxygen in a tissue or the inability to

use oxygen.

Epitsaxis – nosebleed.

Oxygen toxicity – excess oxygen, causing the build up of

peroxides and free radicals.

Chronic obstructive pulmonary diseases (COPD) –

long-term obstruction of airflow and a substantial reduction in

pulmonary ventilation.

Chronic bronchitis – cilia are immobilized and reduced in

number; goblet cells increase their production of mucus →

mucus clogs the airways and breeds infection.

Clinical Disorders & Diseases

Emphysema – alveolar walls break down and the surface

area of the lungs is reduced.

Asthma – allergens trigger the release of histamine and

other inflammatory chemicals that cause intense

bronchoconstriction. In asthma, periodic constriction of the

bronchi and bronchioles makes it more difficult to breathe in

and, especially, out. Attacks of asthma can be triggered by

airborne irritants such as chemical fumes and cigarette smoke

airborne particles to which the patient is allergic.

Clinical Disorders & Diseases

Lung cancer –most common cancer and most common cause

of cancer deaths in U.S. males. There are several forms of lung

cancer, but the most common (and most rapidly increasing)

types are those involving the epithelial cells lining the bronchi

and bronchioles. Ordinarily, the lining of these airways consists

of two layers of cells. Chronic exposure to irritants causes the

number of layers to increase. The ciliated and mucus-secreting

cells disappear and are replaced by a disorganized mass of cells

with abnormal nuclei. If the process continues, the growing mass

penetrates the underlying basement membrane. Malignant cells

can break away and be carried in lymph and blood to other

parts of the body where they may lodge and continue to

proliferate. It is this metastasis of the primary tumor that

eventually kills the patient.

Clinical Disorders & Diseases

Acute rhinitis – the common cold.

Laryngitis – inflammation of the vocal folds.

Pharyngitis – inflammation of the pharynx (sore throat).

Pneumonia – lower respiratory infection of the alveoli that

causes fluid build up in the lungs. It can be caused by many

kinds of both bacteria (Streptococcus pneumoniae) and viruses.

Tissue fluids accumulate in the alveoli reducing the surface

area exposed to air. If enough alveoli are affected, the patient

may need supplemental oxygen.

Clinical Disorders & Diseases

Pleuritis – Inflammation of the pleura, producing more than

the normal amount of fluid, causing a pleural effusion. The pain

fibers of the lung are located in the pleura. When this tissue

becomes inflamed, it results in a sharp pain in the chest that is

worse with breathing in. Other symptoms of pleurisy can

include cough, chest tenderness, and shortness of breath.

Sleep apnea – Cessation of breathing for 10 seconds or

longer during sleep.

Clinical Disorders & Diseases

Tuberculosis – pulmonary infection with Mycobacterium

tuberculosis; reduces lung compliance.

Cystic fibrosis – caused by inheriting two defective CFTR

genes, a transmembrane protein needed for the transport of

Cl− ions out of the epithelial cells of the lung thus enabling

water to follow by osmosis. Diminished CFTR function

reduces the water content of the fluid in the lungs making it

more viscous and difficult for the ciliated cells to move it up

out of the lungs. The accumulation of mucus plugs the airways

interfering with breathing and causing a persistent cough.

Cystic fibrosis is the most common inherited disease in the

U.S. white population.

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Chronic Bronchitis

Bronchi narrow

due to swollen

tissue and

excessive mucus

production.

AsthmaEdema of mucosa, excessive mucosa

production, muscle spasms obstruct

airways.

Emphysema

Alveolar walls torn and can’t repair, alveoli fuse into large

air spaces.

Tuberculosis

COPD

Chronic obstructive

pulmonary disease (COPD)

refers to a group of lung

diseases that block airflow

and make breathing difficult.

Cystic FibrosisCystic fibrosis is a hereditary disorder

characterized by lung congestion and

infection and malabsorption of

nutrients by the pancreas.