Topic 8. Respiratory System

System that provides for exchange of O2 and CO2 to and from the blood.

Respiratory system

Respiratory system can be divided anatomically into the upper and lower respiratory tracts. What are the two?

Conducting and respiratory portion

A portion which consists of the nasal, cavities, pharynx, larynx, trachea, bronchi, bronchioles, and terminal broncioles.

Conducting portion

A portion where the system’s main function of gas exchange occurs, consisting of respiratory bronchioles, alveolar ducts, and alveoli

Respiratory portion

The cellular sites of the exchange of O2 and CO2 between inspired air and blood, are small, air-filled, saclike structures, which make up most of the lung structure.

Alveoli

A portion that cleans and humidifies inspired air and provides conduits for air movement to and from alveoli. To ensure an uninterrupted supply of air, a combination of cartilage, collagen and elastic fibers, and smooth muscle provides with rigid structural support and the necessary flexibility and extensibility

Conducting portion

The nasal cavities lie within the skull as two cavernous chambers separated by the _____

Osseous nasal septum

In nasal cavity, it is extending from each lateral wall are three bony shelflike projection called_____

Conchae

The mucosa covering nasal osseous nasal septum and conchae and other parts of nasal cavity walls has a _______ with important roles in conditioning inhaled air

Lamina propria

It is near the epithelial surface carries blood in a general direction counter to the flow of air and releases heat to warm that air

Complex vasculature

In the process of complex vasculature, while it releases heat to warm that air, it is humidified by water secreted from ______

Small seromucous glands

It uses goblet cells and glands to trap particulate and gaseous air impurities that are then removed. It acts like a magnet for dust, smoke to get stuck in the slime

Thin mucus layer

The secretion also contain ______ from plasma cells in the lamina propria. It is a special type of antibody to grab the virus from air and stick it into the mucus.

Immunoglobulin A

It represents one of the most specialized regions of the respiratory system. It is located primarily in the roof the nasal cavity. This is responsible for the detection, transduction, and initial interpretation of odorant molecules

Olfactory mucosa

This is the only part of respiratory system that can smell and it is located at the very top of the nose. It catches the smell molecules floating in the air and it translates those smells into electric signal then starts the process of telling the brain.

Olfactory mucosa

Histologically, the olfactory mucosa differs markedly from the typical respiratory epithelium. Instead of the pseudostratified ciliated columnar epithelium, the olfactory epithelium is a _____

Neuroepithelium

These bipolar neurons are unique because they are among the new neurons in the human body that regenerate throughout life. Their apical surfaces bear non-motile cilia enriched with odorant-binding protein and receptors. Upon binding, these cilia initiate signal transduction pathways that ultimately send action potentials through the olfactory nerve into the olfactory bulb

Olfactory Receptor Neurons

These cells have tiny, non-moving hairs called cilia, These hairs are covered in special receptors that catch scent particles floating in the air. Once a scent is caught, it sends an electrical signal through the olfactory nerve straight in to the brain’s smell bulb. And these cells in the body are special— they can regenerate throughout the whole life.

Olfactory Receptor Neurons

These columnar cells flank the receptor neurons and provide metabolic and structural support. Their apical microvilli contribute to the mucosal surface, while their cytoplasm contains enzymes that detoxify harmful chemical entering with inhaled air.

Supporting cells

These cells are shaped like tall columns. They stand side-by-side with Olfactory Receptor Neurons to hold them up and keep them organized. Without this, the ORNs wouldn’t have the physical house they need to stay in place

Supporting cells

These stem cells reside near the basal lamina. Their role in the continuous turnover of olfactory neurons, making the olfactory epithelium one of the most active regenerative tissues in the body.

Basal cells

These are the stem cells that live at the very bottom. Their only job is to turn into brand-new scent detectors whenever the old ones get tired or damaged. This make the nose one of the fastest-healing parts of the body

Basal cells

Beneath the epithelium lies the lamina propria that contains _____. It secretes watery, protein-rich fluid that dissolves odorant and continuously washes the epithelial surface, ensuring that new odor molecules can be detected

Bowman’s glands

Underneath all these cells is a layer called the lamina propria. It contains_____ which act like a continuous power washer of the nose. They spray a watery fluid onto the surface to dissolve the smells so the detectors can read them and they also washes away old smells so the nose is always ready to detect something new,

Bowman’s glands

The lamina propria also houses bundles of unmyelinated axons from the receptor neurons. These axons coalesce to form the olfactory nerve filaments that pass through the cribriform plate of the ethmoid bone. These axons are unmyelinated and relatively exposed, thus, they are vulnerable to trauma like head injuries that can lead to ____

Anosmia

The axons that connect the scent detectors to your brain are very delicate and exposed. Because they aren’t protected by a thick shell, a hard hit to the head can snap the connections, leading to _____, which is the total loss of sense of smell

Anosmia

It is a short 4×4 cm passage for air between the pharynx and the trachea. Its rigid wall is reinforced by hyaline cartilage and smaller elastic cartilage, all of which are connected by ligaments. In addition to maintaining an open airway, movements of these cartilages by skeletal muscles participate in sound production during phonation

Larynx

It is a voice box that is 4cm long passage reinforced with cartilage to keep the airway open

Larynx

A flattened structure projecting from the upper rim of the larynx, serves to prevent swallowed food or fluid from entering that passage. Its upper or lingual surface has stratified squamous epithelium

Epiglottis

It is lid in the larynx that flips down when we swallow to stop food from going into the lungs

Epiglottis

The upper pair in the larynx that is partly covered with typical respiratory epithelium overlying numerous seromucous glands and occasional lymphoid nodules to guard against the infection while helping the sound of your voice

Immovable vestibular folds

The lower pair of folds that have features important for phonation or sound production. Each is covered with nonkeratinized stratified squamous epithelium that protects the mucosa from abrasion and desiccation(dryness) from rapid air movement

Vocal folds

A dense regular bundle of elastic connective tissue that supports the free edge of each vocal fold

The vocal ligament

In larynx, deep to the mucosa are large bundles of striated fibers comprising the ______ that allow each vocal fold to be moved

Vocalis muscle

During ______, the muscles of the larynx draw the paired vocal folds together (adduction), which narrows the opening between them, the rima glottidis, and air expelled from the lungs causes the adducted vocal folds to vibrate and produce sound

Phonation

A 10-12cm long in adults is lined with typical respiratory mucosa in which the lamina propria contains numerous seromucous glands producing watery mucus. A series with about a dozen C-shaped rings of hyaline cartilage

Trachea

The open ends of the cartilage rings are on the posterior surface, against the esophagus, and bridged by a bundle of smooth muscled called ______. It relaxed during swallowing to facilitate the passage of food by allowing the esophagus to bulge into the lumen of the trachea. Because the back of the trachea is soft, the tube next to it (the esophagus) can bulge into it when you swallow a big bite of food.

Trachealis muscle

The muscle strongly contracts in the cough reflex to narrow the tracheal lumen and provide for increase velocity of the expelled air and better loosening of material in the air passage. When we cough, this muscle squeezes the tube to make the air move much faster, helping us to blast out any dust and junk that got inside

Trachealis muscle

The trachea divides into two _____ that enter each lung at hilum, along with arteries, veins, and lymphatic vessels.

Primary bronchi

After entering the lungs, the primary bronchi course downward and outward giving rise to_____________, three in the right lung and two in the left lung, each of which supplies a pulmonary lobe

Secondary bronchi

These secondary (lobar) bronchi then divide again, forming ______ . Each of it supplies bronchopulmonary segments, approximately 10-12% each lung with its own connective tissue capsule and blood supply

Tertiary Bronchi

The tertiary bronchi give rise to smaller and smaller bronchi, whose terminal braches are called ______.

Bronchioles

Each bronchiole enters a pulmonary lobule, where it branches to form five to seven ______

Terminal bronchioles

In bronchial tree and lung, they are each pyramid shaped, with the apex aimed at the pulmonary hilum, and each is delineated by a thin layer of connective tissue, which in adults is frequently incomplete

Pulmonary lobules

Within this layer, as the branches get smaller (down to 1-2mm), it contains crisscrossing bundles of spirally arranged smooth muscle and elastic fibers which is prominent in the smaller bronchial branches and contraction of this muscle layer is the one responsible for the folded appearance

Lamina propria

They are the intralobular airways with diameters of 1mm or less, formed after about the tenth generation of branching; they lack both mucosal glands and cartilage, although dense connective tissue is associated with the smooth muscle

Bronchioles

In terminal bronchioles, the type of epithelium has become from ciliated pseudostratified columnar to _______

Ciliated simple columnar/cuboidal epithelium

In bronchioles, they are lined with hairs that form a ______ that is important in clearing debris and mucus by moving it upward along the bronchial tree and trachea

Mucociliary escalator

In terminal bronchioles, these are cuboidal epithelium with non-ciliated dome-shaped apical ends containing secretory granules and its functions are secretion of surfactant, detoxification, and secretion of antimicrobial peptides for local immune defense

Clara cells

The muscular contraction in both bronchi and the bronchioles is controlled primarily by _______

Autonomic Nervous System

These are the layers of a protective membrane called _____ that encloses the lungs within the chest (thoracic cavity)

Pleura

Type of pleura that is inner layer and directly covers the lung tissue itself

Visceral pleura

Type of pleura that is the outer layer that lines the thoracic wall

Parietal pleura

These are the functional units of gas exchange

Alveoli

In alveoli, they are arrange in terminal cluster

Alveolar sacs

In alveoli, these are the cells that are extremely thin squamous facilitating gas exchange

Type 1 pneumocytes

In alveoli, these are the cells that are cuboidal cells that produce pulmonary surfactant where they reduce surface tension within the alveoli, preventing them from collapsing when we exhale. They also help repair alveolar epithelium

Type 2 pneumocytes

To get the oxygen into the blood, our body creates a ______. This structure is designed to minimize the diffusion distance for oxygen and carbon dioxide

Blood air barrier

They contain capillaries, elastic fibers, reticular fibers and macrophages (dust cells). These are the specialized cleaning crew to handle any debris that makes it past the nose and throat

Interalveolar septa

These are found in interalveolar septa. They eat phagocytose dust, pathogens, and surfactant residues

Alveolar macrophages