1 / 27

IPSB - Phys/Path A

Respiratory System (cont.). IPSB - Phys/Path A. Respiratory System. Main function: maintain homeostasis Respiratory system Exchanges O 2 & CO 2 between atmosphere & blood Blood transports O 2 & CO 2 between respiratory system & tissues Primary function

vonda
Download Presentation

IPSB - Phys/Path A

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Respiratory System (cont.) IPSB - Phys/Path A

  2. Respiratory System Main function: maintain homeostasis Respiratory system Exchanges O2 & CO2 between atmosphere & blood Blood transports O2 & CO2 between respiratory system & tissues Primary function Obtain O2 for cells to use & eliminate CO2

  3. Respiratory System Respiration Internal respiration - Intracellular metabolic processes carried out w/in mitochondria External respiration - Sequence of events in exchange of O2 & O2 between external environment & cells of body 1. Mechanical act of breathing 2. O2 & CO2 exchanged between air in alveoli & blood 3. O2 & CO2 transported by blood 4. Exchange O2 & CO2 between tissues & blood Respiratory system - Only involved in ventilation & exchange of O2 & CO2 w/blood

  4. Respiratory System Non-respiratory functions Route for water loss & heat elimination Enhances venous return Contributes to normal acid-base balance Enables speech, singing, & vocalization Defends against inhaled foreign matter Removes, modifies, activates, or inactivates various materials passing through pulmonary circulation Traps & dissolves small blood clots Activates angiotensin II Nose – organ of smell

  5. Respiratory System

  6. Respiratory System - Lungs

  7. Respiratory System Functionally – 2 portions Conducting portion Nose, pharynx, larynx, trachea, bronchi, bronchioles, & terminal bronchioles Respiratory portion – where gas exchange takes place Respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli

  8. Respiratory System Trachea - “windpipe” Tubular passageway for air 12 cm (~5 in) in length 2.5 cm (~1 in) in diameter Anterior to esophagus Extends from larynx to superior border of T5 Divides into left/right bronchi Layers of tissue Mucosa Epithelial layer of pseudostratified ciliated columnar epithelium Ciliated columnar cells & goblet cells

  9. Respiratory System Trachea - “windpipe” Layers of tissue Submucosa Areolar connective tissue Seromucous glands & ducts Hyaline cartilage 16-20 incomplete rings of cartilage Look like letter “C” Horizontally oriented, vertically stacked Open part faces esophagus – slight expansion of esophagus during swallowing Transverse smooth muscle fibers & elastic connective tissue Hold open ends of rings together Rings – semirigid support – don't collapse Adventitia – areolar connective tissue Joins trachea to surrounding tissues

  10. Respiratory System Bronchi Right primary & left primary bronchus Connect trachea to lungs Right – more vertical, shorter & wider Objects tend to catch here Contain incomplete cartilage rings Pseudostratified ciliated columnar epithelium Further subdivide in lungs down to terminal bronchioles Smooth muscle in bronchioles Contraction – autonomic nervous system & chemicals Asthma attack – smooth muscle contracts shrinking airways

  11. Respiratory System Lungs Paired cone-shaped organs Lie in thoracic cavity Separated by heart & other structures Mediastinum Separates thoracic cavity into 2 distinct chambers One lung may collapse, other expanded 2 layers of serous membrane (pleural membrane) Parietal pleura – superficial layer Lines thoracic cavity Visceral pleura – deep layer Covers lungs Pleural cavity – potential space between pleura Lubricating fluid

  12. Respiratory System Lungs Right broader/thicker than left Shorter on right – diaphragm accomodates liver Lobes Two lobes on left 3 lobes on right Each receives own secondary bronchus Made up of lobules Lobules Compartment wrapped in elastic connective tissue Has lymphatic vessel, venule, arteriole, & branch from terminal bronchiole Divide into respiratory bronchioles

  13. Respiratory System Lungs Lobules (cont.) Respiratory bronchioles – microscopic branches Subdivide into alveolar ducts Numerous alveoli and alveolar sacs around circumference of ducts. Alveolar sacs - 2 or more alveoli that share common opening Walls -2 types of alveolar epithelial cells Type I – simple squamous epithelial lining wall Gas exchange takes place here Type II – rounded or cuboidal epithelial Free surface contain microvilli Secrete alveolar fluid – keep sacs moist Alveolar macrophages – dust & other debris

  14. Respiratory System Lungs Lobules (cont.) Alveolar capillary membrane surrounds sacs Gas exchange via diffusion Multiple layers Layer of Type I & Type II alveolar cells w/ wandering macrophages Epithelial basement membrane under alveolar wall Capillary basement membrane – fused w/ epithelial basement membrane Endothelial cells of capillary

  15. Lobules & Alveolar Sacs

  16. Lobules & Alveolar Sacs

  17. Lobules & Alveolar Sacs

  18. Respiration Pulmonary Ventilation Process by which gases are exchanged between the atmosphere & lung alveoli Air flow from pressure gradient Air moves in lungs when pressure in lungs lower Air moves out of lungs when pressure in lungs greater Inspiration Breathing in Air pressure in lungs = pressure of atmosphere Differences in pressure force air into or out of lungs Changes in lung volume

  19. Respiration Inspiration (cont.) First step – contraction of principal inspiratory muscles Diaphragm Most important Dome-shaped skeletal muscle forms floor of thoracic cavity Innervated by phrenic nerve Nerve fibers from C3, C4, & C5 Contraction causes it to flatten – lowers dome (1-10cm) Accounts for ~75% of air that enters lungs during inspiration External intercostals Contract at same time Pulls ribs superiorly Pushes sternum anteriorly Increase anterior-posterior dimension of thoracic cavity

  20. Respiration Inspiration (cont.) Negative pressure differential between pleura When thoracic cavity expands, pulls parietal pleura Visceral pleura & lungs pulled out too Lungs expand, pressure drops in alveoli Air flows from region of high pressure to low Expiration – breathing out Pressure differential like inspiration but other direction Normal expiration passive process Elastic recoil of chest wall & lungs Starts when inspiratory muscles relax

  21. Respiration Expiration (cont.) Active exhalation Labored breathing Air movement impeded (COPD) Requires abdominals and internal intercostals to contract Breathing patterns Eupnea – normal quiet breathing Apnea – temporary cessation of breathing Dyspnea – painful or labored breathing Costal breathing – shallow (chest) breathing Diaphragmatic breathing – deep abdominal breathing SCM elevate sternum, scalenes elevate top 2 ribs, pect. Minor elevate 3rd thru 5th ribs

  22. Respiration Alveolar Surface Tension Thin fluid layer on inside alveolar sacs Exerts downward force – surface tension Produces inwardly directed force Causes alveoli to assume smallest possible diameter Surface tension must be overcome during inspiration Not as great as water Due to surfactant – detergent-like substance Produced by Type II alveolar cells Premature babies – no or little surfactant Breathing more labored Alveoli can collapse

  23. Respiration Lung Volumes & Capacities Respiration – 1 inspiration & 1 expiration Average rate – 12 respirations per minute Moves ~ 6 l of air in & out at rest. Rates & volumes measured using spirometer ~500 ml moves in & out of airways Volume of one breath – Tidal Volume (TV) ~70% reach alveoli Remaining ~30% (150 ml) in anatomical dead spaces Take deep breath > 500 ml Additional inhaled air – inspiratory reserve volume (IRV) Up to ~3100 ml more

  24. Respiration

  25. Respiration Lung Volumes & Capacities (cont.) Inhale normal and then forced exhalation Push out additional 1200 ml + 500 ml tidal volume Called expiratory reserve volume (ERV) Residual volume in lungs even after forced expiration ~1200 ml (RV) Inspiratory capacity = tidal volume + inspiratory reserve volume ~3600 ml Functional residual capacity = residual volume + expiratory reserve volume (~2400 ml) Vital capacity = IRV + TV + ERV (~4800 ml)

  26. Control of Respiration Respiratory Center Bilaterally in medulla oblongata & pons Functionally divided into 3 areas Medullary rhythmicity area of medulla oblongata Controls basic rhythm of respiration Normally 2 sec inspiration & 3 sec expiration Pneumotaxic area in pons Coordinates transition between inhale & exhale Limits duration of inhalation Apneustic area in pons Activates prolonged inspriation Inhibits expiration Occurs when pneumotaxic area is inactive

  27. Control of Respiration Respiratory Center Regulation Cerebral cortex connections – voluntarily alter respiration Central chemoreceptors in medulla Monitor levels of O2 & CO2 Peripheral chemoreceptors Monitor levels of O2 & CO2 Walls of systemic arteries Also sensitive to H+ Located in aortic body – wall of arch of aorta Also in carotid bodies Oval nodules in wall of left & right common carotid arteries

More Related