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18 Unit 1 Chapter 18. 18 Unit 1 Helps pH control Pulmonary ventilation Moving air in & out External respiration Gas exchange between alveoli & blood Internal.

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Presentation on theme: "18 Unit 1 Chapter 18. 18 Unit 1 Helps pH control Pulmonary ventilation Moving air in & out External respiration Gas exchange between alveoli & blood Internal."— Presentation transcript:

1 18 Unit 1 Chapter 18

2 18 Unit 1 Helps pH control Pulmonary ventilation Moving air in & out External respiration Gas exchange between alveoli & blood Internal respiration Gas exchange between blood & cells

3 18 Unit 1 Upper respiratory tract nose, pharynx Lower Respiratory System Trachea, larynx & bronchi & lungs Conducting zone = tubing Respiratory Zone= Gas exchange Bronchioles, alveolar sacs & alveoli

4 Figure 18.1

5 18 Unit 1 Nose: external nares  nasal cavity  internal nares Nasal septum splits in two Nasal conchae swirl air over mucus membrane Designed to: Filter, Warm, Humidify Trap dust and infectious agents Detect olfactory stimuli Modify vocal sounds

6 18 Unit 1 Funnel shaped tube from internal nares to larynx = “throat” Upper = naso pharynx Middle = oropharynx Between uvula & top of epiglottis lower = laryngeal pharynx Connects with both esophagus & larynx Thus both air & food & drink

7 Figure 18.2

8 18 Unit 1 Short tube of cartilage Thyroid cartilage- anterior = “Adam's apple” Epiglottis – upper leaf-shaped piece During swallowing larynx moves up and epiglottis covers opening to trachea Cricoid cartilage- forms inferior wall Paired arytenoids- above cricoid attach to vocal cords & pharyngeal muscles

9 Figure 18.3

10 18 Unit 1 Mucous membrane of larynx  two pairs of folds Upper = false vocal cords Lower = true vocal cords Contain elastic ligaments stretched between cartilage Move out into air way and vibrate Pitch adjusted by tension and diameter of ligaments

11 18 Unit 1 Trachea- larynx  upper part of T5 vertebra  R. & L. primary bronchus Lined with pseudostratified ciliated mucous membrane  dust protection – move toward pharynx C-shaped cartilage rings keep lumen open

12 18 Unit 1 Bronchi also contain cartilage rings Primary bronchi enter the lungs Blood vessels, lymphatic vessels & nerves enter lungs with bronchi In lungs branch  secondary bronchi one for each lobe of lung  tertiary bronchi   terminal bronchi Smaller bronchi have less cartilage and more smooth muscle ANS can adjust diameter = resistance to flow

13 18 Unit 1 Two organs (R. & L) Surrounded by pleural membrane Parietal pleura attached to diaphragm & thoracic wall Visceral pleura attached to lungs Between is pleural cavity filled with fluid Broad bottom = base; Pointy top = apex Right lung has 3 lobes Left lung has 3 lobes & cardiac notch

14 18 Unit 1 Divided in lobules fed by tertiary bronchus Further divisions  terminal bronchiole  respiratory bronchiole Lined with non-ciliated cuboidal epithelium  alveolar ducts  alveolar sacs 

15

16 18 Unit 1 Cup-shaped out pouch of sac Lined with thin alveolar cells (simple squamous) Scattered surfactant secreting cells Lowers surface tension & humidifies Alveolar macrophages- “cleaners” Gases diffuse across combined epithelia of alveolus & capillary Combination called: Respiratory Membrane

17 Figure 18.5

18 Figure 18.6

19 18 Unit 1 Air flows between atmosphere & lungs due to difference in pressure Caused by respiratory muscles Inhalation: diaphragm & external intercostals Diaphragm contracts   lung volume Lung moves due to seal between parietal & visceral plura

20 18 Unit 1 Resting exhalation due to muscle relaxation= passive process Diaphragm rises & ribs fall   lung volume Can be active using internal intercostals & abdominal muscles Push diaphragm up & pull ribs in  More  lung volume

21 Figure 18.7a

22 Figure 18.7b

23 18 Unit 1  lung volume   alveolar pressure Atmospheric pressure is constant Atmospheric > alveolar  inhalation During exhalation   lung rises Alveolar> Atmospheric  exhalation

24 Figure 18.8

25 18 Unit 1 Frequency (f) = breaths per minute Normal ~12 breaths per min Tidal volume (TV) = volume moved in one breath Normal ~ 500 ml Minute Ventilation (MV) = f x TV ~ 70% of TV reaches alveoli (350 ml) Only this involved in gas exchange 30% in airways = Anatomic Dead Space

26 18 Unit 1 Inspiration beyond resting = Inspiratory reserve volume Expiration beyond resting (active) = Expiratory reserve volume Air left after a maximum expiration = residual volume

27 18 Unit 1 Inspiratory capacity= TV + inspiratory reserve Functional residual capacity = Residual volume + expiratory reserve Vital capacity (VC) = Expiratory reserve + TV + Inspiratory reserve Total lung capacity = VC + residual

28 Figure 18.9

29 18 Unit 1 Eupnea = normal breathing Highly variable in pattern Special modifications for speech and emotional responses Also variations fro coughing & sneezing to clear airways See table 18.1

30 18 Unit 1 Mixture of gases (N2, O 2,, CO2, H2O & others) Each gas has own partial pressure (P x ) Each gas diffuses down partial pressure gradient Total = sum of partial pressures = atmospheric pressure

31 18 Unit 1 O 2 diffuses from air (P O2 ~105mm Hg)  incoming blood (P O2 ~40mm Hg) Continues until equilibrium (P O2 ~105mm Hg) Some unexchanged mixture in out flow so Arterial blood is ~100 mmHg Meanwhile blood (P CO2 ~45) diffuses to alveolar air (P CO2 ~40) Again to equilibrium

32 18 Unit 1 Occurs throughout body O 2 diffuses from blood to cells P O2 lower in cells because of use Meanwhile CO 2 diffuses in opposite direction

33 Figure 18.10

34 18 Unit 1 O 2 dissolves poorly 98.5% bound to hemoglobin in RBCs Binding depends on P O2 High at lung and lower at tissue P O2 s Tissue release of O 2 increased by: High CO 2 Acidity Higher temperatures

35 18 Unit 1 As comes in to blood from cells  Some dissolved (7%) Bound to proteins including Hemoglobin (23%) Becomes bicarbonate ions (70%) CO 2 + H 2 O H + + HCO 3 - Process reverses at lungs

36 Figure 18.11

37 18 Unit 1 Medullary respiratory area in medulla Contains both inspiratory & expiratory areas Quiet breathing: inspiratory area  nerve signals to inspiratory muscles for ~2 sec  inspiration Then becomes inactive & muscles relax  Expiration Expiratory centre active only during forceful breathing Area in pons adjusts length of inspiratory stimulation

38 Figure 18.12a

39 Figure 18.12b

40 18 Unit 1 Cortical input: voluntary adjustment of patterns Protection & talking Chemoreceptor input will override breath-hold Chemoreceptor input Central receptors in medulla Peripheral receptors in arch of aorta respond to increased H + or P CO2  increased ventilation Thus negative feedback loop to maintain blood & brain pH Significant falls in P O2 also stimulates breathing

41 Figure 18.13

42 18 Unit 1 Limbic system- anticipation of activity or emotion can stimulate Proprioception  stimulates on start of activity Temperature  warming increases Pain- Sudden pain  apnea Prolonged somatic pain can increase rate Airway irritation  cough or sneeze Inflation reflex- bronchi wall stretch receptors inhibit inspiration Prevents overinflation

43 18 Unit 1 Everything becomes less elastic  Decrease in Vital capacity Can decrease blood O 2 level Decreased exercise capacity Decreased macrophage activity Increased susceptibility to pulmonary disease


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