Week 4 Lecture Notes 4 - Human Structure and Function PDF

lOMoARcPSD|43778768 Week 4 - Lecture notes 4 Human Structure and Function (Curtin University) Scan to open on Studocu Studocu is not sponsored or endorsed by any college or university Downloaded by turkan alnasar (aln...

lOMoARcPSD|43778768 Week 4 - Lecture notes 4 Human Structure and Function (Curtin University) Scan to open on Studocu Studocu is not sponsored or endorsed by any college or university Downloaded by turkan alnasar ([email protected])  lOMoARcPSD|43778768 HSF C4 L1- anatomy of the respiratory system Functions of the respiratory system 1. Respiration Ventilation- movement of air in and out of lungs External respiration- gas exchange between lungs and blood Transport of respiratory gases Internal respiration- gas exchange between blood and tissues 2. Regulation of blood pH 3. Voice production 4. Smell (olfaction) 5. Protection Divisions of the respiratory system Structural classification Upper- nose – nose cavity- pharxy  Upper respiratory tract Lower – larynx – bronchi – bronchioles – aviola of lungs  Lower respiratory tract Functional classification  Conducting zone  Respiratory zone (in lungs) Nose 1 External nose and nasal cavity Nasal cavity  From nostrils (nares) to choana  Vestibule- entry to nasal cavity Stratified squamous epithelium, sweat and sebaceous glands and hair follicles  Hard palate- floor of nasal cavity  Septum- separates nasal cavity into left and right parts Cartilage and bone Nose 2 Nasal cavity  Concha- bony “ridges” in nasal cavity Superior, middle and inferior concha Superior, middle and inferior meatus  Concha vs. choana  Epithelium of concha (and most of nasal cavity) is pseudostratified ciliated columnar epithelium Functions of the nasal cavity  Passageway for air  Cleans the air  Humidifies and warms the air Via warm blood flowing through nasal cavity Via moisture from mucous epithelium and excess tears which drain into nasal cavity  Olfaction (smell) Downloaded by turkan alnasar ([email protected])  lOMoARcPSD|43778768  Sound of your voice Pharynx (throat) 3 regions 1. Nasopharynx  Posterior to nasal cavity  Pseudostratified ciliated columnar epithelium  Houses openings of Eustachian tubes  Posterior surface of nasopharynx has the pharyngeal tonsils 2. Oropharynx  Posterior to oral cavity  Stratified squamous epithelium  Palatine tonsils and lingual tonsils 3. Laryngopharynx  Lies posterior to epiglottis  Stratified squamous epithelium Larynx Also knows as voice box  Passageway for air  Made up of 9 cartilage 6 paired Arytenoid Corniculate Cuneiform 3 unpaired Thyroid (Adam’s apple) Cricoid Epiglottis Functions of the larynx  Maintains an open passageway for air movement  Directs food into the oesophagus away from respiratory tract  Sound production via vocal folds  Trap debris from entering lungs Trachea Windpipe  Descends from the larynx and sits anterior to the oesophagus  Has 15-20 ‘C-shaped’ hyaline cartilage rings for support  Dense connective tissue and smooth muscle in between cartilage rings  Tracheal lumen lined with pseudostratified ciliated columnar epithelium with goblet cells (mucous producing) Tracheobronchial tree Moving from trachea to terminal bronchioles:  Increase in smooth muscle Downloaded by turkan alnasar ([email protected])  lOMoARcPSD|43778768  Decrease in cartilage  Change in epithelial lumen from pseudostratified ciliated columnar to simple ciliated columnar to simple ciliated cuboidal Alveoli Lungs Cone shaped with a base and apex  Left lung has 2 lobes + cardiac notch  Right lung has 3 lobes  Lobes separated by fissures  Hilum on medial surface- entry point for blood and nervous supply, lymphatic vessels and bronchi Lungs 2 Hilum  Bronchopulmonary segments Pleura HSF C4 L2- Gas exchange The respiratory membrane  Alveolus side  Capillary side Downloaded by turkan alnasar ([email protected])  lOMoARcPSD|43778768  Gas exchange Factors affecting gas exchange throughout the respiratory membrane 1 1. Thickness of the respiratory membrane Thicker membrane reduces the rate of movement of gas 2. Surface area Lower surface area reduces volume of gas exchange taking place 3. Diffusion coefficient Diffusion coefficient- how easily a gas can diffuse in and out of a liquid or tissue A relative number 4. Partial pressure- pressure exerted by each gas in a mixture of gases When partial pressure (Pp) of a gas is greater on one side of the membrane compared to the other, the gas moves from higher Pp to lower Pp Gas transport 1 Oxygen (O2) Transported via:  Red blood cells (haemoglobin 98.5%)  Dissolved in blood plasma (1.5%) Carbon dioxide (CO2) Transported as:  HCO3- dissolved in plasma (70%)  CO2 dissolved in plasma (7%)  Bound to haemoglobin (23%) Downloaded by turkan alnasar ([email protected])  lOMoARcPSD|43778768 HSF C4 L3- Ventilation Pulmonary ventilation 1 Process of moving air into and out of the lungs Structures involved  Lungs  Diaphragm  Rib cage  Sternum  Intercostal muscles Pulmonary ventilation 2 Inspiration Expiration L Volume increases as it fills w air Volume decreases as air leaves D Moves inferiorly and flattens Moves superiorly as it relaxes into dome shape RC Elevated Depresses S Elevated Depresses IM Contract Relax Airflow in and out of alveoli 1 Boyle’s law- volume is inversely proportional to pressure Air moves from HP to LP Airflow in and out of alveoli 2  Barometric air pressure (PB) = atmospheric air pressure outside the body  Intra-alveolar pressure (Palv) = pressure inside the alveoli PB is normally 760 mm Hg so will be equal to 0 mm Hg  Palv is 759mm Hg = -1mm Hg  Palv is 761 mm Hg = 1 mm Hg End of expiration PB = Palv  No flow of air During inspiration PB > Palv  Air flows from the outside of the body to the inside of your lungs End of inspiration PB < Palv  No flow of air Downloaded by turkan alnasar ([email protected])  lOMoARcPSD|43778768 During expiration Palv > PB  Air flows from the side of the lungs to the outside of the body Changing alveolar volume Intrapleural pressure = pressure in the pleural cavity Forces which promote alveoli recoil:  Alveoli are covered in fine elastic fibres  Fluid which coats alveoli= surfactant Forces which promotes lungs expansion  Intrapleural pressure < intraalveolar pressure  Visceral pleura adhering to parietal pleura HSF C4 L4 – respiratory volumes and capacities Pulmonary volumes Tidal volume  The amount of air inspired or expired with each breath Inspiratory reserve volume  The amount of air that can be inspired forcefully after inspiration of the tidal volume Expiratory reserve volume  The amount of air that can be forcefully expired after expiration of the tidal volume Residual volume  The volume of air still remaining in the respiratory passages and lungs after the most forceful expiration Pulmonary capacities The sum of two or more pulmonary volumes Inspiratory capacity  Amount of air a person can inspire maximally after normal expiration (TV + IRV) Functional residual capacity  Amount of air remaining in the lungs at the end of a normal expiration (ERV + RV) Vital capacity  Max volume of air that cab be expelled from the respiratory tract after a max inspiration (IRV + TD + ERV) Total lung capacity  Inspiratory reserve volume + expiratory reserve volume + tidal volume + residual volume Some definitions Respiratory rate (RR): number of breaths taken per minute Minute ventilation: total amount of air moved into and out of the respiratory system each minute (TV x RR) Anatomic dead space: space formed by nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles and terminal bronchioles Alveoli ventilation: volume of air available for gas exchange per minute Downloaded by turkan alnasar ([email protected])  lOMoARcPSD|43778768 Measuring lung function Why? To diagnose and monitor diseases of the lungs (asthma, chronic obstructive pulmonary diseases) How? Static versus dynamic Using a spirometer What? Lung volumes and capacities Dynamic lung function 1 Lung volume measurement in relation to time  Vitalograph Parameters measured: Forced vital capacity (FVC)  Maximal volume of air that can be forcefully expired as fast as possible after a deep breath in Forced expiratory volume in 1 second (FEV1 sec)  The volume of air expired in the first second of the test Forced expiratory volume 1% (FEV1%)  FEV1 sec expressed as a percentage of the FVC Downloaded by turkan alnasar ([email protected])  lOMoARcPSD|43778768 Depth of breathing Description Volume Quite Min movement of rib cage 5000ml Moderate Downloaded by turkan alnasar ([email protected])