BIO 202 Respiratory System

Intrapreural Pressure

(Pip) - pressure within the pleural cavity

Intrapulmonary pressure

(Ppul) - pressure within the alveoli

Respiration Process

1. Pulmonary ventilation - moving air into and out of the lungs. 2. External respiration - gas exchange between the lungs and the blood. 3. Transport - transport of oxygen and carbon dioxide between the lungs and tissues. 4. Internal respiration - gas exchange between systemic blood vessels and tissues. All to supply the body with oxygen and dispose of carbon dioxide.

Pulmonary ventilation

A mechanical process that depends on volume changes in the thoracic cavity. Volume changes lead to pressure changes, which lead to the flow of gases to equalize pressure.

Lung cancer

Accounts for 1/3 of all cancer deaths in the U.S. 90% of all patients with lung cancer were smokers

Vasalva's meneuver

Air is temporarily held in the lower respiratory tract by closing the glottis Causes intra-abdominal pressure to rise when abdominal muscles contract Helps to empty the rectum Acts as a splint to stabilize the trunk when lifting heavy loads

Inspiratory Reserve Volume (IRV)

Air that can be inspired forcibly beyond the tidal volume (2100-3200 ml)

Tidal Volume (TV)

Air that moves into and out of the lungs with each breath (approximately 500 ml)

Functional Residual Capacity (FRC)

Amount of air remaining in the lungs after a tidal expiration (RV + ERV)

Residual volume (RV)

Amount of air remaining in the lungs after a tidal expiration (RV + ERV)

Bronchial veins

Anastomose with pulmonary veins

Dead space

Anatomical dead space - volume of the conducting respiratory passages (150 ml) Alveolar dead space - alveoli that cease to act in gas exchange due to collapse or obstruction Total dead space - sum of alveolar and anatomical dead spaces

Alveoli

Approximately 300 million. Account for most of the lungs' volume . Provide tremendous surface area for gas exchange. microscopic chambers at termini of bronchial tree.

Alveolar Walls

Are a single layer of type I epithelial cells. Permit gas exchange by simple diffusion. Secrete angiotensin converting enzyme (ACE).

Larynx

Attaches to the hyoid bone. Continuous with the trachea posteriorly. Provides a patent airway. Acts as a switching mechanism to route air and food into the proper channels Function in voice production. Closed during coughing, sneezing, and Valsalva's maneuver.

Lung collapse

Caused by equalization of the intrapleural pressure with the intrapulmonary pressure.

Asthma

Characterized by dyspnea, wheezing, and chest tightness Active inflammation of the airways precedes bronchospasms Airway inflammation is an immune response caused by release of IL-4 and IL-5, which stimulate IgE and recruit inflammatory cells

Conducting Zone

Conduits for air to reach the sites of gas exchange Includes all other respiratory structures e.g., nose, nasal cavity, pharynx, trachea.

Respiratory zone

Defined by the presence of alveoli; begins as terminal bronchioles feed into respiratory bronchioles.

Loudness

Depends upon the force at which the air rushes across the vocal cords.

Surfactant

Detergent-like complex, reduces surface tension and helps keep the alveoli from collapsing

Pitch

Determined by the length and tension of the vocal cords

Carbon dioxide transport

Dissolved in plasma - 7 to 10% Chemically bound to hemoglobin - 20% is carried in RBCs as carbaminohemoglobin Bicarbonate ion in plasma - 70% is transported as bicarbonate (HCO3-)

Nasal mucosa and Conchae

During inhalation- filter, heat, and moisten air During exhalation- reclaim heat and moisture Minimize heat and moisture loss.

Chronic Obstructive Pulmonary Disease

Exemplified by chronic bronchitis and obstructive emphysema. Patients have a history of: Smoking. Dyspnea, where labored breathing occurs and gets progressively worse. Coughing and frequent pulmonary infections, victims develop respiratory failure.

Orapharynx

Extends inferiorly from the level of the soft palate to the epiglottis. Serves as a common passageway for food and air.

Trachea

Flexible and mobile tube extending from the larynx into the mediastinum. Composed of three layers Mucosa - made up of goblet cells and ciliated epithelium. Submucosa - connective tissue deep to the mucosa. Adventitia - outermost layer made of C-shaped rings of hyaline cartilage.

Bronchioles

Have a complete layer of circular smooth muscle. Lack cartilage support and mucus-producing cells.

Tuberculosis ( Mycobacterium tuberculosis)

Infectious disease caused bacteria. Symptoms include fever, night sweats, weight loss, a racking cough, and splitting headache. Treatment entails a 12-month course of antibiotics.

Pons Centers

Influence and modify activity of the medullary centers Smooth out inspiration and expiration transitions and vice versa.

Expiration

Inspiratory muscles relax and the rib cage descends due to gravity. Thoracic cavity volume decreases Elastic lungs recoil passively and intrapulmonary volume decreases. Intrapulmonary pressure rises above atmospheric pressure (+1 mm Hg) Gases flow out of the lungs down the pressure gradient until intrapulmonary pressure is 0.

Speech

Intermittent release of expired air while opening and closing the glottis

Transpulmonary pressure

Keeps the airways open, difference between the intrapulmonary and intrapleural pressures (Ppul - Pip)

Nasopharynx

Lies posterior to the nasal cavity, inferior to the sphenoid, and superior to the level of the soft palate. Strictly an air passageway.

Airway resistance

Major nonelastic source of resistance to airflow. As it rises, breathing movements become more strenuous Severely constricted or obstructed bronchioles: Can occur during acute asthma attacks which stops ventilation. Epinephrine release via the sympathetic nervous system dilates bronchioles and reduces it.

Alveolar ventilation rate (AVR)

Measures the flow of fresh gases into and out of the alveoli during a particular time.

Lungs

Paired composite organs that flank mediastinum in thorax. Composed of alveoli and respiratory passageways. contains stroma which allows them to recoil passively during expiration.

Bronchial tree

Part of conducting zone. consists of right and left bronchi which subdivide into secondary bronchi, each supplying a lobe of the lungs.

Respiratory Mucosa

Part of nasal cavity and lines the balance of it. Nasal glands secrete containing lysozymes and epithelial cells secrete defensins to help destroy bacteria. Sensitive _____ triggers sneezing when stimulated by irritating particles.

Respiratory Zone

Part of respiratory system. Site of gas exchange . Consists of bronchioles, alveolar ducts, and alveoli.

Atmosphere pressure (Patm)

Pressure exerted by the air surrounding the body . Negative respiratory pressure is less than Patm . Positive respiratory pressure is greater than Patm.

Bronchial arteries

Provide systemic blood to the lung tissue

Nose (only externally visible part of respiratory syst)

Provides an airway for respiration. Moistens and warms entering air. Filters inspired air and cleans it of foreign matter. Housing the olfactory receptors. Resonating chamber for speech.

Breathing

Pulmonary ventilation, consists of two phases Inspiration - air flows into the lungs Expiration - gases exit the lungs

Pharynx

Resonates, amplifies, and enhances sound quality.

Factors that affect lung compliance

Scar tissue/fibrosis. Blockage of the smaller respiratory passages with mucus or fluid.Reduced production of surfactant. Decreased flexibility of the thoracic cage or its decreased ability to expand (ossification in old age).

Paranasal Sinuses

Sinuses in bones that surround the nasal cavity Sinuses lighten the skull and help to warm and moisten the air.

Total lung capacity (TLC)

Sum of all lung volumes (approximately 6000 ml in males)

Alveolar surface tension

The attraction of liquid molecules to one another at a liquid-gas interface. The liquid coating the alveolar surface is always acting to reduce the alveoli to the smallest possible size.

Inspiration

The diaphragm and external intercostal muscles contract and the rib cage rises.The lungs are stretched and intrapulmonary volume increases. Intrapulmonary pressure drops below atmospheric pressure (1 mm Hg). Air flows into the lungs, down its pressure gradient, until intrapulmonary pressure = atmospheric pressure.

Pleura

Thin, double-layered serosa. Parietal _____: -Covers the thoracic wall and superior face of the diaphragm. -Continues around heart and between lungs. Visceral, or pulmonary, _____ covers the external lung surface.

Dalton's law of partial pressures

Total pressure exerted by a mixture of gases is the sum of the pressures exerted independently by each gas in the mixture. The partial pressure of each gas is directly proportional to its percentage in the mixture

Nitric oxide (NO)

Vasodilator that plays a role in blood pressure regulation.

Laryngopharynx

Voice box. Serves as a common passageway for food and air Lies posterior to the upright epiglottis.

Henry's Law

When a mixture of gases is in contact with a liquid, each gas will dissolve in the liquid in proportion to its partial pressure. The amount of gas that will dissolve in a liquid also depends upon its solubility: Carbon dioxide is the most soluble Oxygen is 1/20th as soluble as carbon dioxide Nitrogen is practically insoluble in plasma

Expiratory Reserve Volume (ERV)

air that can be evacuated from the lungs after a tidal expiration (1000-1200 ml)

Pulmonary veins

carry oxygenated blood from respiratory zones to the heart

Epiglottis

elastic cartilage that covers the laryngeal inlet during swallowing

Sound

is "shaped" into language by action of the pharynx, tongue, soft palate, and lips

Acidosis

may reflect: Carbon dioxide retention. Accumulation of lactic acid. Excess fatty acids in patients with diabetes mellitus.

Hemoglobin (Hb)

molecule binds four oxygen atoms in a rapid and reversible process. The _____-oxygen combination is called oxi-____(HbO2). Saturated - when all 4 hemes of the molecule are bound to oxygen. Partially saturated- when 1-3 hemes are bound to oxygen. 20-25% of bound oxygen is unloaded during one systemic circulation. Is a vasoconstrictor and a nitric oxide scavenger.

Pulmonary arteries

supply systemic venous blood to be oxygenated

Lung compliance

the ease with which lungs can be expanded

Boyle's law

the relationship between the pressure and volume of gases P1V1 = P2V2 P = pressure of a gas in mm Hg V = volume of a gas in cubic millimeters Subscripts 1 and 2 represent the initial and resulting conditions, respectively.

Vital capacity

the total amount of exchangeable air (TV + IRV + ERV)

Inspiratory capacity

total amount of air that can be inspired after a tidal expiration (IRV + TV)