Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
The Respiratory System Part 4: Regulation & Maintenance The Respiratory System Respiratory System: The system of the body primarily concerned with gas exchange, namely carbon dioxide & oxygen. Oxygen is essential for metabolic reactions that produce the energy required for all life processes. Carbon Dioxide is the waste product of the metabolic reactions that must be removed from the body. Excessive buildup can lead to acidity that can be toxic to cells. Respiration Respiration: 3 meanings… Ventilation of the lungs (breathing) Exchange of gases between air & blood and blood & tissue fluid Use of oxygen in cellular metabolism Functions of the Respiratory System Provides gas exchange by in taking oxygen & delivering it to the body cells & eliminating carbon dioxide waste products produced in the body cells. Helps to regulate the blood pH. Contains receptors for the sense of smell, filters inspired air, and produces sound for vocalization. Respiratory Anatomy 6 Principle Organs of the Respiratory System: Nose Pharynx Larynx Trachea Bronchi Lungs Respiratory Anatomy Conducting Division: Organs that enable the passage of airflow. Respiratory Division: Any tissue where gas-exchange occurs. Alveoli: Sacs in the lungs that exchange gas. Respiratory Anatomy Upper Respiratory Tract: The airway from the nose through the larynx. Lower Respiratory Tract: The airway from the trachea through the lungs. Respiratory Path Air flows from the… nasal or oral cavity pharynx trachea primary bronchi secondary bronchi tertiary bronchi bronchioles alveoli. Nose Nose: The organ responsible for detecting odors, cleansing & humidifying the air we breath, adding resonance to the voice. by bones & cartilage – alar, septal, & lateral cartilages. External Nares: The two openings commonly known as the nostrils. Nasal Cavity: The cavity that extends from the external nares to the back of the internal nares aka the choanae. Vestibule: The anterior portion of the cavity. Nasal Fossae: The two halves of the nasal cavity. Supported Nasal Septum: Divides the nasal cavity into the nasal fossae. Nose Superior, Middle & Inferior Conchae: The projections or shelves along the walls of the chambers. Superior, Middle & Meatuses: The narrow nature of the passages helps trap moisture during exhalation & insures that incoming air is moist as well. Cilia (hair) & mucus in the cavity traps debris and sweeps it up & out of the pharynx to be swallowed & digested (or spit out). Pharynx Pharynx: The portion we think of as the “throat”. Funnel-shaped, muscular tube above 5 inches long. Extends from the internal nares to the cricoid cartilage of the larynx. Main function is a passageway for food or air. Also serves as a resonating chamber for our voices & houses the tonsils. Pharynx 3 Regions of the Pharynx: Nasopharynx: Lies just beneath the nasal cavity & extends to the soft palate. Opens to the internal nares & the auditory tubes/eustachian tubes. Leads directly to the… Oropharynx: Lies between the soft palate & hyoid bone. Houses both the lingual & palatine tonsils. Fauces: The opening to the mouth! Leads directly to the… Laryngopharynx: Begins at the hyoid bone & opens into both the esophagus & larynx. Esophagus leads to the stomach for food. Larynx leads to the lungs for air. Larynx Larynx: Connects the pharynx with the trachea. Called the “voicebox” Important for keeping foods & liquids out of the airway. 9 Cartilages make up the wall of the larynx. 1 Epiglottis 1 Thyroid Cartilage 1 Cricoid 2 Arytenoids 2 Corniculate 2 Cuneiform Larynx Glottis: The superior opening of the larynx. Epiglottis: The guarded flap of tissue that keeps food from the airway. Extrinsic Muscles: Cause the larynx & pharynx to rise when swallowing takes place – this causes the epiglottis to close downward like a lid & prevent food from entering the airway. Larynx Mucus Membranes: Membranes line the larynx with two pairs of folds. Ventricular Folds aka False Vocal Cords: True Vocal Cords: Inferior to the false vocal cords, which produces sound via elastic ligaments stretched between the cartilage. Intrinsic Muscles create tension to pull on the corniculate and arytenoid cartilages which causes the sound of the air passing through the larynx to change in pitch. When the cords are pulled tight, the pitch produced is higher. When the cords are relaxed, the pitch produced is lower. Volume is adjusted via the force of the air through the larynx. Trachea Trachea: Known as the windpipe – about 5 inches long, connecting the larynx to the right & left pulmonary bronchi. Mucus Layers: From deepest to superficial… Mucosa Submucosa Hyaline Cartilage Adventitia Primary Function of the Mucus Layers: Keep dust & small particles out of the lungs. C-Shaped Cartilage Rings: Keep the trachea from collapsing when we inhale, & ciliated epithelial cells help to sweep mucus upwards & outwards to keep debris out of the lungs. When Things Go Wrong with the Trachea… Tracheotomy: An operation where an opening is made in the trachea to bypass any obstruction. Intubation: A procedure in which a tube is inserted into the mouth or nose & guided down the respiratory tract to the lungs. Bronchi Carina: An internal ridge where the trachea separates into the right & left primary bronchus. The mucous membrane of the carina is the most sensitive area of the entire laryns for initiating a cough reflex. Bronchi: The paths that divide off into the lungs from the trachea. Right Primary Bronchus: Goes to the right lung. Left Primary Bronchus: Goes to the left lung. The primary bronchi further divide into the smaller bronchi. Bronchi Secondary (Lobar) Bronchi: The branch of the brinchi that supply each lobe of the lung. Tertiary (Segmental) Bronchi: Further branches of the secondary bronchi. Bronchioles: The smallest branches of the bronchi, lacking cartilage, but have smooth muscle in the walls. 2 go to the left lung, 3 to the right. Primary Lobule: The portion of lung that is supplied by each bronchiole. Terminal Bronchioles: Bronchioles are divided into 5080 terminal bronchioles. These further divide into small respiratory bronchioles which divide into alveolar ducts & end in the alveolar sacs (where gas exchange occurs). The Lungs Lungs: The paired, cone-shaped organs that are located in the thoracic cavity to rapidly exchange gas. Hilun: The depression point at which each lung receives the bronchus, blood vessels, lymphatic vessels, & nerves. The Lungs Pleural Membranes: Two layers of serous membranes which enclose & protect each lung. Parietal Pleura: The superficial layer that lines the wall of the thoracic cavity. Visceral Pleura: Covers the lungs. Pleural Cavity: The small space between the visceral & parietal pleurae. Pleural Fluid: The lubricating fluid that allows the membranes to move easily over one another during breathing, & causes the membranes to have surface tension (stick together). The Lungs Base: The broad, inferior portion of the lungs. Apex: The narrow, superior portion of the lungs. Costal Surface: The surface of the lungs that lies against the ribs. Mediastinal (Medial) Surface: Contains the hilus (where the bronchi, blood vessels, & nerves enter & exit). Root: Formed by the pulmonary artery & veins, bronchus, bronchial arteries & veins, pulmonary plexuses of nerves, lymphatic vessels, bronchial lymph glands, & areolar tissue all enclosed in the pleura. The Lungs Cardiac Notch: The indentation in the anterior border of the left lung. The left lung is about 10% smaller than the right lung. The right lung is thicker & broader than the left lung because the diaphragm is higher on the right side. Alveoli Alveoli: Microscopic functional units of the lungs, where gas exchange takes place. Alveolus: The cup shaped structure lined with simple squamous epitheliun & surrounded by a basement membrane. Alveolar Sacs: Made up of two or more alveoli that share a common opening. Alveoli Alveolar Epithelial Cells: Two types of cells that line the walls of the epithelial cells. Type 1 Alveolar Cells: Most prevalent type - the mane sites of gas exchange. Type 2 Alveolar Cells aka Septal Cells: Secrete alveolar fluid, which keeps the surface between the cells and the air moist & produces surfactant. Found between the Type 1 Alveolar Cells Surfactant: An element of alveolar fluid that lowers its surface tension & reduces the tendency of alveoli to collapse. Alveoli Respiratory Membrane: Exchanges oxygen & carbon dioxide by diffusion across the alveolar & capillary walls. Extends from the alveolar air space to the blood plasma. Consists of 4 layers: Alveolar Wall: Consists of Type 1 & 2 Alveolar Cells & Alveolar macrophages (wandering macrophages that remove dust particles & other debris from the lungs. Epithelial Basement Membrane: Underlies the alveolar wall. Capillary Basement Membrane: Fuse to the basement membrane. Endothelial Cells: Cells of the capillaries. Blood Supply to the Lungs Pulmonary Arteries aka Bronchial Arteries: Main arteries that supply blood to the lungs. Pulmonary Trunks: Deoxygenated blood travels through the pulmonary trunk to the lungs to become oxygenated. Divides into the left pulmonary artery (serves the left lung) & right pulmonary artery (serves the right lung). Oxygenated blood then returns to the heart through one of the four pulmonary veins that drain into the left atrium. Blood Supply to the Lungs Ventilation-Perfusion Coupling: The phenomenon of the blood vessels in the lungs undergoing vasoconstruction as a result of hypoxia to divert the blood from poorly ventilated areas to well ventilated areas to optimize oxygenation. Bronchial Arteries: Branch from the aorta to deliver oxygenated blood to nourish the lungs. Most blood then returns to the heart through the pulmonary veins. Superior vena cava returns any blood that drains into the bronchial veins or branches of the azygos systems. Respiration Respiration: The process of gas exchange. 3 steps… Pulmonary Ventilation: The mechanical flow of air into & out of the lungs – breathing! External Respiration: The exchange of gases between the alveoli of the lungs & the blood in the pulmonary capillaries, aided by the thin walls of the capillaries & alveoli. Blood in the pulmonary capillaries loses carbon dioxide & gains oxygen. Internal Respiration: The exchange of gases between the blood in the systemic capillaries & tissue cells. Air flow is due to the alternating pressure differences caused by the contraction & relaxation of the respiratory muscles. Blood in the systemic capillaries loses oxygen to the tissue cells & gains carbon dioxide. Cellular Respiration: The metabolic reactions within all cells that consume oxygen & give off carbon dioxide while producing ATP for energy. Inhalation Inhalation aka Inspiration: The act of breathing in – considered active due to muscular contractions involved. Phrenic nerves stimulate the diaphragm to cause a downward contraction. The external intercostal muscles are stimulated by this and raise the ribs. The chest cavity and the lungs expand to fill the space, increasing the volume and decreasing the pressure. Inhalation: Atmospheric Pressure Air pressure inside the lungs is equal to the atmospheric pressure (1 atmosphere or 760 mm). Pressure inside the alveoli is lower than atmospheric pressure when the volume of the lungs increases (inhalation). This causes air to be forced into the lungs! The air in the lungs is now higher in atmospheric pressure than the air outside the body, which leads to expiration. Boyle’s Law: The pressure of a gas in a closed container is inversely proportional to the volume of the container – as the volume increases, the pressure decreases! Inhalation: Pressure Intrapleural Pressure: The level of pressure between the two pleural lining layers, which is always lower than atmospheric pressure. Alveolar (Intrapulmonic) Pressure: The pressure inside the lungs that decreases as the volume of the lungs & thoracic cavity increases. Causes a pressure difference between the alveoli & atmosphere, forcing air to flow from the area of high pressure (outside) to low pressure (inside lungs). Compliance: The amount of effort that is required to expand the lungs & the chest wall. High compliance means the chest wall & lungs will expand easily. Muscles of Respiration Diaphragm: The dome-shaped skeletal muscle that forms the floor of the thoracic cavity. Contraction causes the ribs & sternum to elevate, increasing the front-to-back dimension of the thoracic cavity. Contraction causes the air pressure decrease in the lungs that forces air into the body. Contraction accounts for 75% of air entering the body! The most important muscle in inhalation! Muscles of Respiration External Intercostals: The muscles running between the ribs. Contraction leads to elevation of the ribs. Contraction accounts for 24% of the air entering the body! Second most important muscle for inhalation. Exhalation Exhalation aka Expiration: The act of breathing out - considered passive unless forced. Elastic Recoil helps to force the air back from the area of high pressure (inside the lungs) to the area of low pressure (outside the body). Elastic Recoil: The returning of the chest wall & lungs to normal shape after the stretching that occurs during inhalation. This is aided by…. The recoil of elastic fibers within the tissue that had been stretched during inhalation. The inward pull of the surface tension of the lungs, caused by the alveolar fluid. Let’s Review – Breathing! Diaphragm & External Intercostal muscles contract, causing the diaphragm to move downward and the ribs & sternum to lift. Movement causes the vertical dimensions of the thoracic cavity to increase, causing the air pressure in the lungs to decrease. Decrease in air pressure causes air to flow from the area of high atmospheric pressure (outside the body) to the area of low atmospheric pressure (inside the lungs). Let’s Review – Breathing! Relaxation of the inspiratory muscles causes exhalation to start! Elastic recoil occurs in the diaphragm & external intercostal muscles, decreasing the dimensions of the thoracic cavity. This decreases the volume of the lungs, causing the pressure to increase. Air is forced from the area of high atmospheric pressure (inside the lungs) to the area of low atmospheric pressure (outside the body). When Respiration Goes Wrong… Chronic Obstructive Pulmonary Disease (COPD): Any disorder causing a long-term obstruction of airflow, which reduces pulmonary ventilation. When Respiration Goes Wrong… Asthma: Allergens trigger the release of inflammatory chemicals, causing bronchoconstriction and thick mucus production. Can lead to death from suffocation! When Respiration Goes Wrong… Chronic Bronchitis: The inflation of the bronchi & immobilization of the cilia – causes a chronic cough to help bring up sputum. When Respiration Goes Wrong… Emphysema: The break down of the alveolar walls, leading to enlargement of the remaining alveolar sacks. Much less respiratory membrane is then available for gas exchange, requiring 3-4 times the normal amount of energy to help breathe. When Respiration Goes Wrong… Smoking! When Respiration Goes Wrong… Smoking! Chronic Bronchitis Emphysema X 2 Lung Volume & Capacity Respiration Rate: The average number of breaths taken per minute. Healthy minute. adults average 12 breaths per Lung Volume & Capacity Tidal Volume (Vt): The amount (volume) of air moved with each breath. Varies from one person to the next. Approximately 70% of tidal volume (350mL) moves into the functional sections of the respiratory system. Approximately 30% (150mL) remains in the conducting airways – the anatomic dead space. Alveolar Ventillation Rate: The volume of air per minute that reaches the alveoli & respiratory portions of the lungs – measured as the functional tidal volume multiplied by the respiratory rate. AVR = 350mL/breath X 12 breaths/min = 4200 mL/minute. Lung Volume & Capacity Minute Ventilation (MV): The total volume of air inhaled & exhaled each minute – calculated as the respiratory rate multiplied by the tidal volume. MV = 12 breaths/min X 500mL/breath = 6 liters/minute. If this is lower than normal it can be a sign of pulmonary malfunctioning! Lung Volume & Capacity Inspiratory Reserve Volume: The difference in inhaled air volume between normal tidal volume and the tidal volume of a deep breath. Normal tidal volume = 500mL Normal inspiratory reserve volume = 3100mL 3100mL is the amount that is more than normal – you actually take in 3600mL. Lung Volume & Capacity Expiratory Reserve Volume: The amount of air typically left in the lungs after a normal exhalation. Forced Expiratory Volume (FEV1.0): The volume of air that can be forcefully exhaled from the lungs in one second, after a maximum inhalation & using maximum effort. Approximately 1200mL in healthy adults. In English: The amount of air you can exhale during 1 second if you take the deepest breath possible and blow as hard as you can! Residual Volume: The amount of air still remaining in the lungs in the noncollapsible airways even after the expiratory reserve volume is exhaled. Minimal Volume: The amount of residual volume remaining should the thoracic cavity open. The change in pressure causes some residual volume to be lost as the pressures of the cavity & the outside world attempt to equalize. Lung Volume & Capacity Lung Capacity: The combinations of specific lung volumes. Inspiratory Capacity: The sum of tidal volume & inspiratory reserve volume. 500mL + 3100 mL = 3600 mL Functional Residual Capacity: The sum of residual volume & expiratory reserve volume. 1200mL + 1200mL = 2400mL Vital Capacity: The sum of inspiratory reserve volume & expiratory reserve volume. 3600mL + 1200mL = 4800mL Total Lung Capacity: The sum of vital capacity & residual volume 4800mL + 1200mL = 6000mL Lung Volume & Capacity Spirometer (Respirometer): An instrument used to measure the respiratory rate & the tidal volume. Spirogram: The graph of the spirometer readout. Upward Deflection shows inhalation. Downward Deflection shows exhalation. Gas Exchange Laws – Dalton’s Law Dalton’s Law: Each gas in a mixture of gases exerts its own pressure as if no other gases were present. Partial Pressure (Px): The pressure on a specific gas (x) in a mixture – this controls the movement of oxygen & carbon dioxide from the atmosphere to the lungs, to the blood, & to the tissue. Determined by multiplying the percentage of each gas in the mixture by the total pressure of the mixture. The greater the partial pressure, the faster the diffusion of the gases across a permeable membrane from the area of higher pressure to the area of lower pressure. Total Pressure: The sum of all the partial pressures in a gas mixture. Gas Exchange Laws - Henry’s Law Henry’s Law: The quantity of gas that will dissolve in a liquid is proportional to the partial pressure of the gas & its solubility coefficient. The higher the partial pressure & the higher the solubility in the solution, the easier it is for the gas to stay within the fluid. Example: Soda! While the bottle is closed, the partial pressure is high, causing the CO2 to stay within the liquid. When the bottle is opened, the pressure drops, allowing the CO2 to escape! Gas Exchange Laws - Charles’ Law Charles’ Law: At a constant pressure, the volume of a given quantity of gas is directly proportional to the absolute temperature. As the temperature rises, the volume rises the same “percentage”. Example: If the temperature doubles, the volume doubles. Oxygen Oxyhemoglobin: A binding of oxygen with the heme portion of hemoglobin (4 iron atoms) found within the blood. + O2 Hb- O2 This allows oxygen to be transmitted by the blood! 98.5% of blood oxygen is bound to hemoglobin. 1.5% of oxygen is dissolved in blood plasma itself – this is the oxygen that gets transported into tissue cells. Hb Deoxyhemoglobin: Oxyhemoglobin that has unloaded its oxygen. This occurs when blood oxygen reaches a tissue area with lower partial pressure. Oxygen Partial Pressure of Oxygen: The higher the partial pressure of oxygen, the more it can combine with hemoglobin. Fully Saturated: The term given to deoxyhemoglobin that is completely converted to oxyhemoglobin – hemoglobin that is full of oxygen! Partially Saturated: The term given to hemoglobin that’s a mix of deoxyhemoglobin & oxyhemoglobin – hemoglobin mixes that are oxygenated & deoxygenated. Percent Saturation of Hemoglobin: The average saturation of hemoglobin with oxygen. Can be almost 100% when the oxygen’s partial pressure is high (fully saturated) or low (partially saturated) if the partial pressure is low. Oxygen Affinity: The tightness of the bond between the Hb (hemoglobin) & oxygen. Oxygen-Hemoglobin Dissociation (Saturation) Curve: The measure of the level between oxygen levels & hemoglobin saturation. Can be shifted left for a higher affinity or right for a lower affinity via 4 main factors… Oxygen Factors Affecting Oxygen-Hemoglobin Dissociation (Saturation) Curve: Acidity: As acidity increase, pH decreases, causing a decrease in the Hb/O2 affinity. Bohr Effect: The shift in the curve to the right, allowing O2 to dissociate from Hb readily. If acidity lowers, pH increases, and we see a left shift as the Hb/O2 affinity increases. Partial Pressure of the O2- CO2: Can cause a right curve, increasing the affinity, due to a resulting increase in acidity. Temperature: The higher the temperature, the more O2 is released from the Hb. 2,3-bisphosphoglycerate (BPG): A substance found in the red blood cells that decreases the affinity & helps unload oxygen from the Hb. Carbon Monoxide Poisoning Carbon Monoxide: A colorless, odorless gas with a VERY high affinity for hemoglobin! Elevated levels of carbon monoxide can cause carbon monoxide poisoning! Carbon monoxide binds to hemoglobin at 200 times the strength of oxygen’s bond! Pure oxygen can help… sometimes. Symptoms: Lips & oral mucosa appear bright cherry red, flu-like symptoms of headache & nausea, etc. Carbon Dioxide Carbon Dioxide: Normal waste product of cellular respiration. 53mL of gaseous carbon dioxide (CO2) present every 100mL of deoxygenated blood in normal resting conditions. 3 Methods of CO2 Transport: Dissolved: Approximately 9% dissolved in blood plasma – once this reaches the lungs, it diffuses into the alveolar air & is exhaled. Carbamino Compounds: 13% combines with amino acid groups & proteins in the blood to form carbamino compounds. Bicarbonate Ions: 78% of CO2 transported in the blood plasma this way. CO2 diffuses into systemic capillaries, enters the red blood cells, reacts with water & carbonic anhydrase (CA) enzymes, & forms carbnic acid. Carbonic acid then dissociates into hydrogen & bicarbonate ions. Carbon Dioxide Haldane Effect: The lower the amount of oxyhemoglobin, the higher the CO2 carrying capacity of the blood. Basically, the more oxygen the blood is carrying, the less carbon dioxide it can pick up, and visa versa. Gas Exchange in Tissue Diffusion: The movement of particles from an area of high concentration to an area of low concentration. For gas exchange: The blood supply in the alveolar capillaries has a high concentration of CO2 while the outside air does not, causing CO2 to move out of the blood & into the air to be exhaled. The outside air has a high concentration of O2 while the blood supply in the alveolar capillaries has a low concentration of O2, causing O2 to move from the outside air into the blood supply. Control of Respiration Respiratory Center: The group of neurons in the brainstem that controls the respiratory muscles – connected to the cortex to allow conscious control.. 3 areas: Medullary Rhythmicity Area: Controls the basic rhythm of respiration located in the medulla oblongata. Pneumotaxic Area: Helps coordinate the transition between inhalation & exhalation – Inspiratory Area: Stimulates the muscles of inspiration. Expiratory Area: Stimulates the internal intercostal & abdominal muscles to allow deeper respiration when needed. Baroreceptors: “Stretch” receptors in the lungs that ensure the lungs don’t become overinflated. Inflation Reflex aka Hering-Breur Reflex: The stimulation of the baroreceptors when the lungs reach capacity triggers the start of exhalation while the lack of stimulation during deflation triggers a new round of inhalation. Apneustic Area: Area in the pons that also contributes to the transition between inhalation & exhalation – stimulates the inspiratory area to prlong inhalation when a long, deep breath is needed. The pneumotaxic region overrides the apneustic region when activated, Control of Respiration Voluntary control of breathing: Allows us to hold out breath when needed. Involuntary control of breathing: Once the carbon dioxide & hydrogen waste products build up in the body, the inspiratory center will be strongly stimulated and breathing will be forced to resume. Hypothalamus & limbic systems can alter breathing patterns during emotional reactions as well, e.g. laughing or crying. Air Movements that aren’t breathing: Yawning, sneezing, coughing, laughing, & crying – reflexes! Control of Respiration Chemoreceptors: Sensory neurons that respond to chemicals. Central Chemoreceptors: Respond to changes in the concentration of H+ (hydrogen) & PCO2 (partial pressure of carbon dioxide) in the cerebrospinal fluid. Located in the medulla oblongata. Peripheral Chemoreceptors: Respond to changes in the concentration of H+ (hydrogen) & PCO2 (partial pressure of carbon dioxide) in the blood stream. Located in the aortic bodies as clusters along the wall of the arch of the aorta, & in the carotid bodies along the walls of the left & right common carotid arteries. Control of Respiration Negative Feedback System: System that attempts to keep the level of some given molecule as close to homeostasis as possible. As PCO2 increases, pH decreases, triggering the peripheral chemoreceptors. The peripheral chemoreceptors trigger the inspiratory area to increase the rate & depth of breathing. Hyperventilation: The inhalation of more O2 and exhalation of more CO2 that occurs via deep, rapid breathing until the PO2 and pH return to normal. Typically triggered by panic or anxiety. Control of Respiration Hypercapnia aka Hypercarbia: When arterial PCO2 is lower than normal. When this occurs, the chemoreceptors are not stimulated, so the inspiratory area is not triggered until CO2 accumulates. Other Factors Influencing Breathing Limbic System Stimulation: Anticipation of activities or emotional anxiety will stimulate the limbic system, which in turn stimulates the inspiratory center. Temperature: An increase in body temperature increases the respiration rate, while a drop in body temperature decreases the respiratory rate. Pain: Visceral pain (abdominal) will slow breathing, somatic pain (limbs) will increase breathing, and sudden, severe pain will cause brief apnea (halting the breathing process). Stretching of the Anal Sphincter Muscle: Increases the rate of respiration, particularly in newborns. Irritation of the Airways: Can cause the cessation of breathing, followed by a cough or sneeze to reduce the irritant. Blood Pressure: A rise in blood pressure will decrease the breathing rate, while a drop in blood pressure will increase the breathing rate.