NUR1019 Respiratory System Lecture 1 PDF

Respiratory system (呼吸系统) NUR1019 – Lecture 1 Dr. Wilson Leung 1 Learning Outcomes 1. The Respiratory System 2. Mechanism of Breathing 3. Gas Exchange and Transport 2 The Respiratory System 3  I...

Respiratory system (呼吸系统) NUR1019 – Lecture 1 Dr. Wilson Leung 1 Learning Outcomes 1. The Respiratory System 2. Mechanism of Breathing 3. Gas Exchange and Transport 2 The Respiratory System 3  Introduction. & Oxygen enters blood , remove CO2 from blood to the air Major function: gas exchange (氣體交換) that allows oxygen from the air to enter the blood and carbon dioxide from the blood to exit into the air 1. Inspiration / inhalation (i.e., breathing in): air is as conducted toward from the lungs by a series of cavities, - tubes, and openings. ↳ Mouth bronchus 2. Expiration / exhalation (i.e., breathing out): air is conducted away from the lungs by a series of cavities, tubes, and openings. 4  Introduction Works with the cardiovascular system to accomplish: - Pulmonary ventilation (breathing) – the entrance and exit of - related a External respiration – the exchange of gases betweenfairair andenvironment) air into and out of lungs o Aft in external blood Chappens in the lungs) ( surroundin Internal g fluid cells respiration – the exchange of gases between blood & and tissue fluid & happens body lugs/) for produce inside the body (not in > - cells energy in the. Transport of gases – to and from the lungs and the tissues (from body) transport air different - C parts of Reason for the respiratory events – provide oxygen for and remove carbon dioxide waste from cellular respiration in order to produce IATP ** ) -Energy the aid of cardiovascular system. 5  The Respiratory Tract (上呼吸道) + (鼻腔) (咽) (聲門) (喉) above or below (下呼吸道) trachea Fou (氣管) (支氣管) (細支氣管) (肺) (橫隔膜) 6  The Respiratory Tract (Tract =) The path of air from the nose to the lungs Air is cleansed, warmed and moistened (潤濕) by our respiratory tract. (facilitate gas exchange lungs) in - Cleansed by nasal hairs, cilia, and mucus ) t - - Lysozyme in the mucus helps to kill bacteria trachea digestive - Mucociliary escalator: (protective mechanism mucus) - cilia 12. hairs , , enzyme Kitbacter gen) e - In the trachea and other airways, the cilia beat & upward, carrying mucus, dust, and other trapped contaminants into the pharynx. T relase waste - Warmed by warm blood flowing through blood , Mucociliary spilt Swallow vessels close to the airway surface or escalator DI orFe - Moistened by the mucous membraneI ↳ facilitate gases exchange in lungs. 7  The Nose & no bones , only The only external portion of the respiratory system Air enters through the nostrils (鼻孔) 2 nasal cavities ↳ Inacal) DE (cavities) - Separated by a septum (隔膜) (bone and cartilage) - Lined by a mucous membrane - Eb - Nasal conchae increase the surface area for moistening and effectiveness of Et warming inhaled air > - make sure the gases exchange. - Odor receptors (氣味受體) located in the olfactory epithelium (roof of nasal cavity 8 The Nose Paranasal sinuses Olfactory epithelium 9  The Nose channel between eyes and nose tears drain Tears empty into the nasal cavities by way of the & ~ in hose - nasolacrimal canals (鼻淚管) ↳ - Crying produces a runny nose (流鼻涕) Paranasal sinuses (鼻竇) spaces > - - Air-filled spaces function - Reduce the weight of the skull : (change quality ↑ voices of function - Act as resonating chambers for the voice : The nasal cavities are separated from the oral cavity by the palate (齶) hard palate (ii) soft palate (/) , - A partition that has two portions, hard palate and soft palate ↑ made of bones & made of muscles 10  The Nose (Maxilla and palatine bones) 11  The Pharynx (Throat) RIPE Funnel (漏斗)-shaped passageway that connects the nasal and oral cavities to the larynx > the - n narrow. down Three parts: (three parts of larynx / 1. Nasopharynx (鼻咽) 2. Oropharynx (口咽) 3. Laryngopharynx (喉咽) C Tonsils (扁桃體) contain lymphocytes (B W port of cells and T cells) (淋巴細胞) that protect immune system against invasion of inhaled pathogens i E - consists Passageway for both food and air > - of oral and nasal 12 cavity. The Larynx (Voicebox) & (Adam's apple/ (A) # #T ↓ Cartilaginous passageway for air between the pharynx (咽) and trachea (氣管) D- A triangular box whose apex (頂尖), the Adam’s apple, is located at the anterior neck Houses the vocal cords (聲帶) – supported by elastic ligaments * - When air is expelled (驅逐) past the vocal cords through the glottis, the vocal cords vibrate, producing sound. 13 The Larynx (Voicebox) ↳ F Voice pitch (音高) regulated by the tension (緊張) on the vocal cords and opening of glottis (聲門) - The greater the tension, as the glottis becomes more narrow, the higher the pitch - Loudness depends on the amplitude (振幅) of the vibrations - How much the vocal cords vibrate *E A At puberty, the growth of the larynx and vocal cords is much faster and accentuated (強調) in males than in females (men cannot ↓ pitch that make the voice tight be - A more prominent Adam’s apple (喉結) deeper results in voice. - Deeper voices (longer vocal cords) The epiglottis (會厭) prevents food from entering the larynx - A flat elastic cartilage (prevent food go trachea in 14 The Trachea (Windpipe氣管) Connects the larynx to the primary bronchi (支氣管) Anterior (前) to esophagus in front of esophages Held open by about twenty C-shaped cartilaginous rings S - Creates a patent airway ↳ - Allows for expansion of the esophagus Mucociliary escalator - Epithelial cilia sweep mucus produced by goblet cells LE BE IT) E - Smoking is known to destroy these cilia. be cleared hence carse respiratory problems Conce cilia destroyed , mucus cannot , 15 Mucociliary escalator in the Trachea 16 The Bronchial Tree The trachea divides into the right and left primary bronchi (支 氣管) that lead into the right and left lungs The primary bronchi branch into secondary bronchi - Three for the right lung (3 lobes) - Two for the left lung (2 lobes) – allow room for the heart The secondary bronchi divide into tertiary bronchi - Supported by smaller plates of cartilage Bronchioles (細支氣管) are the smallest conducting airways - No cartilage support - Possess a ciliated epithelium and a well-developed smooth muscle layer Each bronchiole leads to air sacs called alveoli (肺泡) (singular: alveolus) Where oxygen is exchanged for carbon dioxide 17 The Lungs ↓ T Paired, cone (錐體)-shaped organs - Right lung: 3 lobes - Left lung: 2 lobes – allow room for the heart Each lobe is divided into lobules At. - Each lobule has a bronchiole and Smaller pulmonary arteries / arterioles / & arteries capillaries that serve many alveoli ↑ 18  The Lungs Enclosed by a double layer of serous membrane (漿膜) called the pleurae (胸膜) (singular: pleura) Corgan) The visceral pleura adheres to the surface of the lung > - the directly surround. lung The parietal pleura lines the inside of the thoracic cavity CASAE) Produces a lubricating serous fluid that (wateres also creates surface tension (表面張力) surface tension) between the layers → allows the 2 pleural makesurelga layers to cling together, thus holding the lungs open against the chest wall I 19  The Alveoli (air sacs) purpose : With each inhalation, air passes through the bronchial tree to the alveoli. ↑ Alveolar sac (肺泡囊) surrounded by extensive pulmonary capillaries (肺微血管) Gas exchange (氣體交換) occurs between the air in the alveoli and the blood in the capillaries Oxygen into and carbon dioxide out the bloodstream Each alveolus is lined with an extremely thin layer of water-based tissue fluid. Gas exchange takes place across moist (濕) cellular membranes. I distend) like balloon a The attractive force created by the fluid’s surface tension (表面張力) helps the , exists air distended (膨脹的) lung tissue to return to its resting position when a person exhales. immune cells ~ Normal alveoli are lined with surfactant (i.e., a film of lipoprotein that lowers E I white blood / surface tension to an acceptable level): prevent the alveoli from completely cells (after L collapsing Dust cells: white blood cells to defend us against any debris or pathogens we might inhale 20 *A Gas exchange in the lungs - The pulmonary artery and arteriole carry oxygen-poor blood (blue), while the pulmonary vein and venule carry oxygen-rich blood (red). 21  Respiratory membrane Facilitates rapid gas exchange Alveolar epithelium and the capillary ( endothelium layered together Y Extremely thin # cells) red blood Chave ( Large surface area (50-70m2) W Surrounding Same as the area of the alveoli alveoli The red blood cells within the capillaries are pressed up against the narrow capillary wall, and little plasma is present. Facilitate the rate of gas exchange 22 Mechanism of Breathing 23 glued Ventilation of sealed-off cannot breathe in air inside rib or else we zage must , E - The lungs lie within the sealed-off thoracic cavity (封閉胸腔). As the respiratory muscles actively expand the volume of the entire thorax, the balloon-like lungs passively expand. lungs - passively > - more. ADE - The surface tension between the visceral and parietal pleura & creates intrapleural pressure (i.e., the pressure between pleura) I - Less than atmospheric pressure LES - Help to keep the lungs inflated (膨脹) A continuous column of air extends from the pharynx to the alveoli of the lungs. 24 Ventilation - Inspiration/Inhalation (吸氣) muscle contraction require Active phase of ventilation (i.e., muscular effort involved) Diaphragm (橫膈膜) contracts and flattens. (downwards) External intercostal muscles (外肋間肌) contract. - The rib cage (肋骨籃) moves upward (向上) and outward (向外). Thoracic cavity volume (胸腔容積) increases, causing the lungs to increase in volume – because the lung adheres to the wall of the thoracic cavity. (pressure lung / inside the Air pressure within the alveoli (i.e., intrapulmonary pressure) decreases. 3 Air flows from an area of higher pressure (atmospheric pressure) to an area of lower pressure (within the lungs) until pressures are equal. Air can move to external environment to lungs 25 Ventilation - Expiration/Exhalation (呼氣) Usually the passive phase of ventilation (i.e., no muscular effort required) The diaphragm relaxes and resumes its dome shape. The external intercostal muscles relax and the rib cage moves down and in. The volume of the thoracic cavity decreases and the lungs recoil (縮). - Due to the elastic tissue built into the lung’s walls and the slight alveolar surface tension Lung volume decreases and the intrapulmonary pressure increases. ↳ Since intrapulmonary pressure is now greater than atmospheric pressure, air will flow out of the lungs until pressure are equal. Air moves from lungs to external 26 27 Maximum Inspiratory Effort (最大吸氣力度) Maximum expansion of the lungs ( When Weese/ Help increase the size of the thoracic cavity larger than normal Allows more air to be inspired Involves the accessory muscles of respiration Let At An ) ↳ - Muscle of the back (Erector spinae 豎脊肌) X - Chest muscle (Pectoralis minor 胸小肌) - Anterior neck muscle (Scalene 斜角肌 and sternocleidomastoid muscles) Use the aid of back and let us breathe more and deeply. 28 Forced Expiration (用力呼氣) During heavy exercise, singing, blow air into a trumpet (喇叭), or blow out birthday candles (生日蠟燭) Increased pressure in the thoracic cavity by: Contraction of internal intercostal muscles (內肋間肌) to force the rib cage (肋骨籃) to move downward and inward Contraction of the abdominal wall muscles (腹肌) to push on the abdominal organs and compress upward against the diaphragm > and breathe push lung the more. - 29 Measurement of Ventilation Spirometer (肺量計) – instrument that records the volume of air exchanged during breathing Spirogram (肺活量圖) – shows the measurements recorded by a spirometer 30 Respiratory Volumes and Capacities Spirogram additional (volumee ↳( At (additioners 31 Respiratory Volumes and Capacities 1. Tidal volume - Normal, relaxed breathing - About 500 mL 2. Vital capacity (At - Maximum volume of air that can be inhaled plus the maximum volume of air that can be exhaled - i.e., the sum of the tidal, inspiratory reserve, and expiratory reserve volumes - Depends on: a. Inspiratory reserve volume - Forced inspiration - Increases the volume of air beyond the tidal volume by about 3,000 mL b. Expiratory reserve volume - Forced expiration - About 1,200 mL 3. Residual volume - Amount of air remaining in the lungs (alveoli) after a forced expiration - About 1,000 mL 4. Dead air space /dead air space) reduce air space by breathe deeply. - Only 70% of the tidal volume does reach the alveoli, but 30% remains the airways. slowly > - and 32  deepth of Control of Ventilation & rate and breathing 12-20 ventilations per minute (adults) Controlled by 2 respiratory centers in the medulla oblongata (延腦) and pons of the brainstem (A) - The phrenic nerve carries impulses to the diaphragm. (phrenic send signals to diaphragm nerve - The intercostal nerves stimulate the external intercostal muscles to contract. - Functioning together, these 2 centers allow normal, quiet breathing (eupnea) - Medulla only: respiration is short, irregular, and gasping 喘氣 33 Control of Ventilation (h) - Influenced by nervous input and chemical input Nervous input -eg. - Input from cerebral cortex (大腦皮層), limbic system, hypothalamus (下丘脑), and other brain centers hyper : (higher than normal) - E.g., Increase when you are angry or frightened (hyperpnea: faster-than- normal respiration) - E.g., Decrease in the soundest stage of sleep - Hering-Breuer reflex – prevents overexpansion of the lungs - When inspiratory depth increases, the stretch receptors (mechanoreceptors) in bronchi, bronchioles, and the walls between the adjacent alveoli are stimulated - In turn, they produce inhibitory (抑制性) nerve signals that travel from the inflated lungs to the respiratory center and causes the center to stop sending out nerve signals 34  Control of Ventilation Chemical input: (The reaction of ions in the blood) The respiratory center is extremely sensitive to the levels of ions makes carbon dioxide and I hydrogen ions. # pH of blood > > presence of Hydroge the the pl value drops ->. normal blood When they rise due to increased cellular respiration during you exercise, the center increases respiratory rate and depth. make sure 7 4 pH :. breath faster deeper to > and - ↓ rebuild CO2 need Chemoreceptors (化學感受器) located in the carotid arteries ( me enzy be well - functioned 頸動脈) (“carotid bodies”) and aorta (主動脈) (“aortic bodies”) are sensitive to blood oxygen levels. When oxygen concentration decreases, these receptors communicate with the respiratory center, and the rate and depth of breathing increase. blood> - have more oxygen in. 35 Gas Exchange and Transport 36  External Respiration Exchange of gases in the lungs - Gases are exchanged between the alveolar air (肺泡氣) and the pulmonary capillary blood (肺微血管血). Oxygen F - Higher concentration in the alveoli fromL- Diffuses from the alveoli into the blood low concentration Coxygen lung) enter the blood in Carbon dioxide - Higher concentration in the blood - Diffuses from the blood in the pulmonary capillaries to the alveoli (carbon dioxide exit the blood / 37 Internal Respiration Exchange of gases in the tissues (inside the body Gases are exchanged between the blood in systemic capillaries and the tissue fluid. # A GENEAL , ↑ An i ↳ Oxygen - Higher concentration in the blood (O2 exit the blood) - Cells are continually consuming O2 during cellular respiration. - Diffuses from the blood into the tissue fluid (O2 enters blood Carbon dioxide (produce the dioxide carbon as waste) - > - Higher concentration in the tissue fluid - CO2 is an end product of cellular respiration. - Diffuses from the tissue fluid into the blood 38 External and Internal Respiration 39  # E] (not Gas Transport – Oxygen Transport ↳ E 97-98% transported by hemoglobin in the red blood cells bright color red - Combined with oxygen – oxyhemoglobin : > - - Released oxygen – deoxyhemoglobin (no oxygen hemoglobin) in E ↳ colour : - Increased blood carbon dioxide, acidity, and temperature all increase the amount of oxygen that oxyhemoglobin releases (especially in tissues). > - Use oxygen to produce carbon dioxide energy , Small amount (2-3%) transported in the plasma ↳ St A) - Oxygen is not very soluble in water 40 Gas Transport – Carbon Dioxide Transport 1. As a dissolved gas in blood plasma and in the cytoplasm of red blood cells – 10% 2. Combine with protein (globin) portion of hemoglobin (carbaminohemoglobin) – 30% 3. Most combines with water, forming carbonic acid (H2CO3) – 60% - Carbon dioxide combines with water to form carbonic acid (H2CO3) - CO2 + H2O → H2CO3 - Carbonic acid dissociates into hydrogen ions (H+) and bicarbonate ions (HCO3-) - H2CO3 → H+ + HCO3- - This reaction is catalyzed by an enzyme, carbonic anhydrase (abundant in red blood cells) - Bicarbonate ions diffuse out of red blood cells into the plasma in exchange for chloride ions - Chloride shift: to maintain the electrical balance between the plasma and the red blood cells - Carbonic acid splits into CO2 and H2O, and the CO2 diffuses out of the blood into the alveoli. Carbon dioxide blood exit the , from human body. remove 41 Gas Transport 42 Respiratory Control of Blood pH normal 7 35-7 45.. The respiratory system helps to regulate pH. Bicarbonate/Carbonic acid buffer system is altered by breathing - Hypoventilation = increased CO2 = decreased pH (high [H+])= acidosis (pH less than 7.35) blood pH level acidic and lower than more. normal - ↑CO2 + H2O → ↑H2CO3 ↑ H+ + HCO3- - Hyperventilation = decreased CO2 = increased pH (Low [H+])= alkalosis (pH greater than 7.45) blood pH level alkalimore higher and normal than - ↓CO2 + H2O → ↓ H2CO3 ↓ H+ + HCO3- - Both acidosis and alkalosis can be fatal because they interfere with cell enzyme functions. (deadly * Elop 43 Reference Longenbaker, S. N. (Ed.) (2020). Mader’s Understanding Human Anatomy and Physiology (10th ed.). McGraw-Hill. 44