Respiratory System

Respiratory System

provides oxygen tot the body, disposes of carbon dioxide, and helps regulate blood pH

Alveoli

it is a terminal air sacs where gas exchange occurs/site of gas exchange

Upper respiratory tract

the passageways from the nose to the larynx

Lower respiratory tract

the passageways from the trachea to alveoli

Nose

the only externally visible part of the respiratory system

Olfactory receptors (sense of smell)

located in the mucosa in the slit-like superior part of the nasal cavity, just beneath the ethmoid bone

Respiratory mucosa

• rest of the mucosa lining in the nasal cavity

• rests on a rich network of thin-walled veins that warms the air as it flows past

Ciliated cells

create a gentle current that moves the sheet of contaminated mucus posteriorly toward the throat (pharynx)

Conchae

• lateral walls of the nasal cavity that are uneven, owing to the three mucosa-covered projections

• increase the surface area of the mucosa exposed to the air

• increase the air turbulence in the nasal cavity

Palate

the nasal cavity is separated from the oral cavity below by a partition

Hard Palate

a palate which is anteriorly supported by bone

Soft palate

a palate which has unsupported posterior part

Cleft palate

• failure of the bones forming the palate to fuse medially

• a genetic defect that results in difficulty of breathing, as well as, oral cavity function problems

Paranasal sinuses

• a ring surrounding the nasal cavity

• located in the frontal, sphenoid, ethmoid, and maxillary bones

Sinuses

• lighten the skull and act as resonance chambers for speech

• produce mucus, which drains into the nasal cavity

Nasolacrimal ducts

drain tears from the eyes, and also empties into the nasal cavities

Rhinitis

• inflammation of the nasal mucosa

• excessive production of mucus that results in nasal congestion and postnatal drip

Sinusitis

• sinus inflammation

• difficult to treat and can cause marked changes in voice quality

Pharynx

• commonly called the throat

• common passageway for food and air

• muscular passageway about 13cm (5in) long that vaguely resembles short length of garden hose

Nasopharynx

It is a region in the pharynx in which air enters the superior portion

Oropharynx

It is a region in the pharynx where the air descends from the nasal cavity

Laryngopharynx

a region in pharynx where air enter the larynx

3 regions of Pharynx

• Nasopharynx

• Oropharynx

• Laryngopharynx

Epiglottis

• a spoon-shaped flap of elastic cartilage

• guardian of the airway

• a flap in the esophagus which inhibits food to enter the larynx

Pharyngotympanic tubes

drain the middle ears open into the nasopharynx

Tonsils

• clusters of lymphatic tissue

• protects the body from infections

Pharyngeal tonsil

• often called the adenoid

• located high in the nasopharynx

Palatine tonsils

a type of tonsil which is located in the oropharynx at the end of the soft palate

Lingual tonsil

a kind of tonsil which lies at the base of the tongue

Tubal tonsil

a tonsil that protects the openings of the pharyngotympanic tubes in the nasopharynx

Tonsillitis

if the pharyngeal tonsil becomes swollen and inflamed (as during a bacterial infection)

Larynx

• the voice box

• routes airs and food in to the proper channels

• plays a role in speech

Thyroid cartilage (Adam’s Apple)

it is shield-shaped and is largest of the hyaline cartilages

Cough reflex

If anything other than air enters the larynx, this will trigger to prevent the substance from continuing into the lungs

Vocal folds (true vocal cords)

• part of the mucous membrane of the larynx that forms a pair of folds

• vibrates with expelled air

• its ability to vibrate allows us to speak

Glottis

slit-like passageway between the vocal folds

Trachea

• commonly called as the windpipe

• 10-12cm / about 4in

• fairly rigid because its walls are reinforced with C-shaped rings of hyaline cartilage

• lines with a ciliated mucosa

Goblet Cells

• cells surrounding the trachea which produces mucus

• mucus production

Lungs

• fairly large organs

• occupies the entire thoracic cavity

Mediastinum

• most central area of the thoracic cavity

• houses the heart, great blood vessels, bronchi, esophagus, and other organs

Apex

the narrow superior portion of each lung and is just deep to the clavicle

Base

the broad lung area resting on the diaphragm

Right lung

a lung that has three (3) lobes

Left lung

a lung that has two (2) lobes

Pleural fluid

slippery serous fluid, which allows the lungs to glide easily over the thorax wall during breathing and causes the two pleural layers to cling together

Pleurisy

• inflammation of the pleurae

• can be caused by insufficient secretion of pleural fluid

• pleural surfaces become dry and rough, resulting in friction

Bronchioles

the smallest of the conducting passageways

Conducting zone structures

serve as conduits to and from the respiratory zone

Stroma

elastic connective tissue that allows the lungs to stretch and recoil as we breath

Alveolar pores

connects neighboring air sacs and provide alternative routes for air to reach alveoli whose feeder bronchioles have been clogged by mucus or otherwise blocked

Alveoli

the final defense for the respiratory system

Alveolar macrophages

• sometimes called “dust cells”

• wander in-and-out of the alveoli picking up bacteria, carbon particles, and other debris

Surfactant

• a lipid (fat) molecule produced by squamous epithelial cells

• coats the gas-exposed alveolar surfaces and is very important in lung function

Pulmonary ventilation

• air must move in and out of the lungs so that the gases in the alveoli of the lungs are continuously refreshed

• commonly called as breathing

External respiration

• gas exchange between the pulmonary blood and alveoli must take place

• made between the blood and the body exterior

Respiratory gas transport

oxygen and carbon dioxide must be transported to and from the lungs and tissue cells of the body via the bloodstream

Internal respiration

• gas exchange occurs between the blood and cells inside the body

• oxygen is unloaded from blood and carbon dioxide is loaded

Cellular respiration

use of oxygen to produce ATP and carbon dioxide, is the cornerstone of all energy producing chemical reactions and occurs in nearly all cells

Mechanics of breathing

volume changes lead to pressure changes, which lead to the flow of gases to equalize the pressure

Inspiration

a phase of breathing when air is flowing into the lungs

Expiration

• phase of breathing when air is leaving the lungs

• passive process that depends more on the natural elasticity of the lungs than on muscle contraction

Intrapulmonary volume

volume within the lungs

Diaphragm and External intercostals

when the inspiratory muscles contract which makes the volume (size) of thoracic cavity increase

Forced expiration

the internal intercostal muscles are activated to help depress the rib cage, and the abdominal muscles contract and help to force air from the lungs by squeezing the abdominal organs upward against the diaphragm.

Intrapleural pressure

pressure within the pleural space which is always negative (meaning it is lower than the pressure inside the lungs).

Atelectasis (lung collapse)

• the lung is useless for ventilation

• occurs when air enters the pleural space through a chest wound, but it may also result from a rupture of the visceral pleura, which allows air to enter the pleural space from the respiratory tract.

Pneumothorax

Air in the intrapleural space

Inspiratory reserve volume (IRV),

• The amount of air that can be taken in forcibly above the tidal volume

• around 3,100 ml

Expiratory reserve volume (ERV)

• The amount of air that can be forcibly exhaled beyond tidal expiration

• approximately 1,200 ml

Residual volume

allows gas exchange to go on continuously even between breaths and helps to keep the alveoli open (inflated)

Vital capacity (VC)

• sum of the tidal volume plus the inspiratory and expiratory reserve volumes

• around 4,800 ml in healthy young men and 3,100 ml in healthy young women (total amount of exchangeable air)

Dead space volume

the air that enters the respiratory tract remains in the conducting zone passageways and never reaches the alveoli to participate in gas exchange

Spirometer

used for measuring respiratory capacities

Bronchial sounds

sounds that are are produced by air rushing through the large respiratory passageways (trachea and bronchi).

Vesicular breathing sounds

• sounds which occur as air fills the alveoli.

• sounds like soft murmurs that resemble a muffled breeze.

Hypoxia

inadequate oxygen delivery to body tissues

Carbon monoxide poisoning

• represents a unique type of hypoxia

• Carbon monoxide (CO) is an odorless, colorless gas that competes vigorously with oxygen for the same binding sites on hemoglobin

phrenic nerves and intercostal nerves

The activity of the respiratory muscles, the diaphragm and external intercostals, is regulated by nerve impulses transmitted from the brain by?

ventral respiratory group

contains both inspiratory and expiratory neurons that alternately send impulses to control the rhythm of breathing.

dorsal respiratory group (DRG)

• integrates sensory information from chemoreceptors and peripheral stretch receptors

• communicates this information to the VRG to help modify breathing rhythms

pons respiratory centers

help to smooth the transitions (modify timing) between inhalation and exhalation during activities such as singing, sleeping or exercising

hyperpnea

breathing more vigorously and deeply because the brain centers send more impulses to the respiratory muscles

Nonneural Factors Influencing Respiratory Rate and Depth

• Physical Factors

• Volition (Conscious Control)

• Emotional Factors

• Chemical Factors

Hyperventilation

an increase in the rate and depth of breathing that exceeds the body’s need to remove carbon dioxide

apnea

cessation of breathing, until the carbon dioxide builds up in the blood again

Chronic Obstructive Pulmonary Disease (COPD)

• exemplified by chronic bronchitis and emphysema

• a major cause of death and disability in the world

chronic bronchitis

a disease where the mucosa of the lower respiratory passages becomes severely inflamed and produces excessive mucus

emphysema

a disease wherein the walls of some alveoli are destroyed, causing the remaining alveoli to be enlarged

common types of lung cancer

• adenocarcinoma

• squamous cell carcinoma

• small cell carcinoma

small cell carcinoma

• (about 20 percent)

• a type of carcinoma which contains lymphocyte-like cells that originate in the main bronchi and grow aggressively in small grapelike clusters within the mediastinum, a site from which metastasis is especially rapid

squamous cell carcinoma

• 25– 30 percent

• a type of carcinoma which arises in the epithelium of the larger bronchi and tends to form masses that hollow out and bleed

adenocarcinoma

• (40 percent of cases)

• a type of carcinoma which originates as solitary nodules in peripheral lung areas and develops from bronchial glands and alveolar cells

Surfactant

• a fatty molecule made by the cuboidal alveolar cells

• lowers the surface tension of the film of water lining each alveolar sac so that the alveoli do not collapse between each breath

Cystic fibrosis (CF)

the most common lethal genetic disease in the United States, strikes in 1 out of every 3,500 to 4,000 births.

infant respiratory distress syndrome (IRDS)

Infants who are born prematurely (before week 28) or in whom surfactant production is inadequate

sudden infant death syndrome (SIDS)

also called as crib death

asthma

caused by chronically inflamed, hypersensitive bronchial passages that respond to many irritants (such as dust mite and cockroach droppings, dog dander, and fungi) with dyspnea, coughing, and wheezing

sleep apnea

occur when throat muscles relax, blocking the airway, or when signals to the respiratory muscles are improperly delivered or not delivered at all