Respiratory System Overview

• The respiratory system is vital, supplying oxygen to cells and removing carbon dioxide. A person can only survive minutes without oxygen.
• The respiratory system filters, warms, and humidifies air, while organs facilitate speech and smell.
• The respiratory system removes excess acid, balancing pH levels.
• The respiratory system includes the nose, pharynx, larynx, trachea, bronchi, and lungs. These form a branching tube ending in alveoli, surrounded by capillaries for gas exchange.
• Structure and function are linked in the respiratory system.
• Trachea is the trunk and bronchial tubes are the branches, further developing into bronchi and alveoli.

Respiratory Tract Divisions

• The respiratory tract is divided into upper and lower tracts to describe symptoms of respiratory issues like colds.
• The upper tract (nose, pharynx, larynx) resides outside the thorax, while the lower tract (trachea, bronchial tree, lungs) is mainly within.
• Upper Respiratory Infection (URI) symptoms involve the sinuses, nasal cavity, pharynx, or larynx.
• A "chest cold" has similar symptoms to pneumonia and affects lower respiratory tract organs.

Respiratory Mucosa

• Respiratory mucosa lines most air distribution tubes, typically ciliated pseudostratified columnar epithelium with cilia.
• Stratified squamous epithelium protects the nostrils, vocal folds, and pharynx.
• Simple squamous epithelium lines the alveoli for gas exchange.
• The respiratory tract cleanses, warms, and humidifies air before it reaches the lungs.

Mucous Blanket

• Pseudostratified columnar epithelial lining in the respiratory tree is covered by mucus.
• 125+ mL of respiratory mucus is the primary air purification mechanism.
• Trapped contaminants are moved toward the pharynx via ciliary escalator.
• Irritants cause cilia to beat faster; prolonged exposure paralyzes cilia and increases mucus production.
• Accumulation of mucus results in smokers cough.

Nose Anatomy

• Air enters through external nares (nostrils) into nasal cavities lined by respiratory mucosa and separated by the nasal septum.
• The nasal cavities are moist from mucus and warm from blood flow. Olfactory receptors are in the superior part of the nasal mucosa.
• Four paranasal sinuses (frontal, maxillary, sphenoid, ethmoid) drain into each cavity and assist with mucus production.
• The sinuses lighten skull bones and act as resonance chambers.
• Sinusitis inflames mucosa in the nasal cavity from colds, causing congestion, swelling, redness, headache, and possible chronic infection.
• Lacrimal sacs drain into the nasal cavity, explaining why the nose drips during crying, allergies, or eye irritation.
• Nasal conchae increase surface area so air warmed and humidified as it passes through the nasal cavity. Breathing through the nose is more effective at humidifying inspired air. Bubbling supplemental oxygen through water adds moisture. “Dry” oxygen removes water, causing respiratory problems.

Pharynx

• The pharynx, or throat, is 12.5 cm (5 inches) long and has three sections.
• The uppermost part called the nasopharynx sits behind the nasal cavities.
• The oropharynx is behind the mouth, and the laryngopharynx is the third, lowest segment.
• The pharynx acts as a passage for air and food.
• The auditory tubes equalize air pressure and connect the middle ears with the nasopharynx
• Tonsils are lymphoid tissue masses in the pharynx's mucous membrane; the lingual and palatine tonsils are in the oropharynx, and the pharyngeal tonsils (adenoids) are in the nasopharynx.
• The tonsils can become infected. Swollen pharyngeal tonsils may force mouth breathing.

Larynx

• The larynx (voice box) below the pharynx contains 9 cartilage pieces, with the thyroid cartilage being largest (Adam's apple).
• Vocal cords stretch across the larynx's interior. Their tension determines the pitch of voice. The opening between the cords is the glottis.
• The epiglottis covers the larynx opening during swallowing to stop food and fluids from entering the trachea.

Trachea

• The trachea (windpipe) is 11 cm (4.5 inches) long and 2.5 cm (1 inch) wide.
• It extends from the larynx to the bronchi, providing an open passage for air.
• The trachea is lined with respiratory mucosa.
• Mucous glands help produce mucus that moves toward the pharynx via the ciliary escalator mechanism.
• 15-20 C-shaped cartilage rings prevent collapse.
• Incomplete rings allow for expansion of the esophagus during swallowing.
• Blockage can be caused by tumors or aspirated objects causing death in minutes.

Ensuring The Trachea Stays Open

• Endotracheal intubation ensures an open airway by placing a tube through nose or mouth.
• A tracheotomy creates an opening in the trachea to insert a suction device or IPPB machine.

Bronchial Tree

• The bronchial tree has thousands of air passages like upside-down tree, with the trachea as trunk.
• Primary bronchi (right and left) act as first branches. The right bronchus tends to receive aspirated objects.
• Secondary smaller bronchi contains cartilage rings. The bronchi then branch into tiny tubes known as bronchioles that contain smooth muscle.

Alveoli

• Bronchioles subdivide into microscopic alveolar ducts ending in alveolar sacs, made up of numerous alveoli.
• Alveoli promotes efficiency in ventilating all alveoli equally.
• Alveoli are continually ventilated with air.
• The respiratory membrane consists of the alveolar wall (surfactant, cells, basement membrane), interstitial fluid, and the pulmonary capillary wall.
• CO2 and O2 diffuse across the respiratory membrane.

Alveoli And the Epithelial Layer

• Alveoli effectively exchange oxygen and carbon dioxide.
• The alveolus walls mostly consist of a single layer of type I simple squamous epithelial cells.
• Capillary walls around alveoli are thin, flat endothelial cells.
• The barrier (<1 micron thick) is called the respiratory membrane.
• Millions of alveoli provide a huge surface area (84 square meters / 915 square feet) for rapid gas exchange.
• The alveoli contain surfactant reduces how strong the watery layer is.
• Type II cells make surfactant, and type I cells are flattened.
• Do not confuse the respiratory membrane with the respiratory mucosa. The respiratory mucosa lines the airways.

Lungs

• Lungs fill the thoracic cavity, surrounding the mediastinum (heart, vessels, thymus, esophagus). Deep fissures divide each lung into lobes. The right lung has three lobes; its left lung has two.

Pleurae

• The pleura is a serous membrane coating lung's outer surface and the rib cage's inner lining.
• The visceral pleura adheres to the lungs; the parietal pleura adheres to the thoracic cavity wall. The space between contains pleural fluid.
• Pleural fluid moistens and lubricates the surfaces allowing them to glide over each other during breathing.

Infant Respiratory Distress Syndrome

• Infant Respiratory Distress Syndrome (IRDS) affects premature infants.
• IRDS affects 50,000 babies and kills 5,000 annually.
• A lack of surfactant is a characterization of the disease.
• Surfactant reduces surface tension, which allows for lung capacity of air is increased as air enters and leaves.
• Infants born before 38 weeks do not fully produce surfactant.
• Many of these infants air sacs collapse due to increased surface tension.
• Efforts to reinflate require baby to work harder.
• Treatment involves using oxygen supplementation, a tube and artificial surfactant.

COPD

• Chronic Obstructive Pulmonary Disease (COPD) is progressive obstruction of expiratory air flow.
• Those with COPD show, chronic cough, breath difficulty and hyperinflated chests.
• COPD commonly consist of both emphysema and bronchitis
• In North America, most COPD has occurred because of tobacco usage, with pollution and asthma being further factors.
• There is no known cure, but medication and lifestyle changes can improve lung function.
• Chronic Bronchitis has two characteristics: inflammation of the lining of the bronchi, and excessive mucus.
• Emphysema results in enlargement and rupturing of alveoli and decrease surface area.

Further Illnesses

• Pleurisy is inflammation of the pleura, causing restricted and painful breath. Tumors and tuberculosis etc are causes.
• Pneumothorax (air presence in lungs) results in a collapsed lung.

Respiration, the Basics

• Respiration is the exchange of CO2 and O2 between the blood and environment.
• A close enough area for gases allows for transport between the air and the circulatory system.

Pulmonary Ventilation, the Basics

• Pulmonary ventilation (also called breathing) transports air into the lungs. This combines as external respiration.
• Internal respiration processes the exchange of gases.
• Cellular respiration uses oxygen for cell metabolism.
• Gasses go to ATP through the movement of gas in the blood.

Pulmonary Ventilation: Breathing

• Breathing happens with two phases: inhaling (inspiration) and exhaling (expiration).
• The lungs affect the pressure inside the cavity. The air is in the lower pressure zone than the high pressure zone. This makes it move.
• The lung walls are in a state of compliant and elastic recoil.

Inspiration

• Inspiration happens when the chest cavity gets bigger. As the wall expand, the lungs also do, which allows air to rush into the alveoli. Volume and pressure are inversely proportional. Pressure in lungs drops during inspiration. Muscles include diaphragm and external intercostal muscles.

Diaphragm Contraction

• The diaphragm flattens as it contracts during inspiration which makes the chest cavity longer from its top to bottom. Insets in the lungs allow the muscles for inspiration increase the volume so the chest cavity has reduced pressure.

Expiration

• Resting, quiet exhalation is a passive motion that happens as the inspired muscles relax and then return to place. The elastic nature of both the lungs and other areas "recoil" and also lower the size. Increased pressure happens as the lung decreases. Above the atmospheric pressure it also helps the air through, which then removes it through the respiratory system. More forceful exhalation comes from internal intercostal and abdominal muscles.

Lung Devices

• Air is measured via the use of a spirometer.
• The tidal volume measures during breathing which is 500ml. During more stressful breathing, an extra 3300 or 1000ml can be inspired or extracted respectively.
• The vital capacity measures the air used or unused during ventilation.
• The lungs also hold in whatever air is extra during breathing.
• Volume is tested as it is impacted in several heart based diseases.
• Normal lung rate is 12-18 mins

Oxygen Therapy

• Oxygen (O2) therapy treats of hypoxia, which involves sending oxygen when there is lack of oxygen. There should be water to avoid damage.

Brainstem control of respiration

• The muscles associated with the nervous impulses that originate in the control can change. Those muscles are nervous and originate in a location of a brain stem. They sense oxygen and acid and stretch. The rhythm stems from a grouping in the medulla which causes the normal rate. In the medulla are DRG, the dorsal and VRG, a ventral grouping. The DRG lets the VRG adjust itself should anything change ie blood. The PRG has help for all the changing conditions. The brain stem has different inputs of different areas for respiration. The cortex has over manual like activity to stop the breath such as blowing.

Respiratory Reflexes

• Sensory neurons can sense acids, blood levels, and oxygen levels and carbon dioxide levels. CO2 impacts and helps drive respiration, which is very quick to fix.

Pulmonary, Reflex

• Lungs hold receptors that influence breath and protect from overinflation . When air is in the lungs, this stimulates receptors and sends impulses to the muscles. When you breath, and the lungs become sufficiently deflated, this stops the receptors from stimulating and helps let start gain.

Breathing, Patterns

• Different terms are used to describe breathing and patterns of respiration which help people state health conditions. Eupnea impacts air is normal and oxygen exchange works, it normal and met. Hyperventilation is slow and shallow breath.Dyspnea or difficulity will affect respiration and cause issues, especially, hypoventilation. One leading death type occurs as an example of this SIDS is caused in baby.

Conditions and Cause

• SIDS occurs at a higher rate, ethnicity and race are possible factors. Having the baby's skin clear and on the back helps reduce that cases. If the breath stops this called apnea, a sleep type in which pauses stops it. CSR occurs in all lung failure conditions, brain tumors, blood flow and injuries.

Gas Exchange

• Blood transports gases. The blood then pumps throughout both areas with tiny gaps. External helps gases exchange between the alveolar and the blood.

High and Low Pressure Zones

• The levels inside the blood are measured with different weights. Air concentration is measured in mm HG. Partial pressure is with P.

The Blood

• Lungs send O2 to the body at a rate of 40 mm HG. Diffusion happens in the transfer of CO2 so partial goes to lower levels in the capillary blood. With this information, carbon dioxide has to flow back through in a transfer that requires a much higher pressure in the blood. Carbon dioxide and other particles are pushed out through the alveolar air.

Respiration

• Exchange between systemic and body is internal. Direction for carbon dioxide is a process of the exchange from external. This happens through the interstitial flow and inside capillaries.

Consumption

• Consumptive uses for a maximum process of oxygen, called Vo2max, helps measure exercise in a person. It increases blood oxygen from both blood and lungs.

System Requirements

• Rich oxygen will enter blood with capillaries with systemic levels and poorly oxidized levels of the capillary blood happen when the blood has oxygen and carbon dioxide. Transport is helped through gas and by having a combination.

Trasnport of Oxygen

• High levels of oxygen are dissolved in the blood which the body has about 20.4mL. Combine hemoglobin in a rate of 21 to help carry it to the body and system cells. By combing in hemoglobin, the red cells form oxyhemoglobin for this process. Levels of oxygen in this hemoglobin act as "oxygen sponge" allowing it rapid process in oxygenating more levels. Oxygenated blood is then at a rate of 97 saturated.

Carbon Transports

• Combining oxygen and as combination, as oxyhemoglobin carries the majority.
• Different gases may harm the blood by incapacitating it from receiving oxygen.

Transporting of Dioxides

• Waste is reduced because cellular metabolism allows the body produce the pH. These happen at limits of venous volumes of 40. Waste removes itself in the alveoli when breathing stops, otherwise dioxides transfer and transfer, the blood to the lungs. These are referred to as in several formats. Different processes happen as well with water, carbonic and anhydrase depending in the state. Most transport is blood flow in this format.

Christian Bohr Studies

• The scientist who conducted the study regarding bloods acidity, pH, blood volumes and also rates impacts the cellular levels of oxygen that are given as a binding affinity oxygen.