Presentation is loading. Please wait.

Presentation is loading. Please wait.

Respiratory System In simple animals, like Platyhelminthes (flatworms), respiration is done by diffusion of oxygen. In annelids, oxygen diffuses from moist.

Similar presentations

Presentation on theme: "Respiratory System In simple animals, like Platyhelminthes (flatworms), respiration is done by diffusion of oxygen. In annelids, oxygen diffuses from moist."— Presentation transcript:

1 Respiratory System In simple animals, like Platyhelminthes (flatworms), respiration is done by diffusion of oxygen. In annelids, oxygen diffuses from moist soil into skin cells Insects have tiny openings called spiracles and special tubes called tracheae Fish use gills Land animals use lungs

2 © 2012 Pearson Education, Inc. Nasal cavity Nostril Larynx Right main (primary) bronchus Trachea Right lung Oral cavity Pharynx Left main (primary) bronchus Left lung Diaphragm Figure 13.1

3 Trachea (Windpipe) Four-inch-long tube that connects larynx with bronchi Walls are reinforced with C-shaped hyaline cartilage Lined with ciliated mucosa ◦Beat continuously in the opposite direction of incoming air ◦Expel mucus loaded with dust and other debris away from lungs

4 © 2012 Pearson Education, Inc. Cribriform plate of ethmoid bone Sphenoidal sinus Posterior nasal aperture Nasopharynx Pharyngeal tonsil Opening of pharyngotympanic tube Uvula Oropharynx Palatine tonsil Lingual tonsil Laryngopharynx Esophagus Trachea Frontal sinus Nasal cavity Nasal conchae (superior, middle and inferior) Nasal meatuses (superior, middle, and inferior) Nasal vestibule Nostril Hard palate Soft palate Tongue Hyoid bone Larynx Epiglottis Thyroid cartilage Vocal fold Cricoid cartilage (b) Detailed anatomy of the upper respiratory tract Figure 13.2b

5 Figure 13.3b

6 Main (Primary) Bronchi Formed by division of the trachea Enters the lung at the hilum Right bronchus is wider, shorter, and straighter than left Bronchi subdivide into smaller and smaller branches

7 Lungs Occupy most of the thoracic cavity ◦Heart occupies central portion called mediastinum Apex is near the clavicle (superior portion) Base rests on the diaphragm (inferior portion) Each lung is divided into lobes by fissures ◦Left lung—two lobes ◦Right lung—three lobes

8 Alveolar duct Alveoli Alveolar duct Alveolar sac Alveolar pores Alveolar duct Alveolus (a) Diagrammatic view of respiratory bronchioles, alveolar ducts, and alveoli Terminal bronchiole Respiratory bronchioles Figure 13.5a

9 Respiratory Membrane (Air-Blood Barrier) Thin squamous epithelial layer lines alveolar walls Alveolar pores connect neighboring air sacs Pulmonary capillaries cover external surfaces of alveoli On one side of the membrane is air and on the other side is blood flowing past

10 Gas Exchange Gas crosses the respiratory membrane by diffusion ◦Oxygen enters the blood ◦Carbon dioxide enters the alveoli Alveolar macrophages (“dust cells”) add protection by picking up bacteria, carbon particles, and other debris Surfactant (a lipid molecule) coats gas- exposed alveolar surfaces

11 © 2012 Pearson Education, Inc. HCO 3 _ + H + H 2 CO 3 CO 2 + H 2 O (a) External respiration in the lungs (pulmonary gas exchange) Oxygen is loaded into the blood and carbon dioxide is unloaded. Alveoli (air sacs) Loading of O 2 Unloading of CO 2 O2O2 CO 2 (Oxyhemoglobin is formed) Carbonic acid Bicar- bonate ion Red blood cell Water Plasma Pulmonary capillary Hb + O 2 HbO 2 Figure 13.11a

12 Gas Transport in the Blood Oxygen transport in the blood ◦Most oxygen travels attached to hemoglobin and forms oxyhemoglobin (HbO 2 ) ◦A small dissolved amount is carried in the plasma

13 Gas Transport in the Blood For carbon dioxide to diffuse out of blood into the alveoli, it must be released from its bicarbonate form: ◦Bicarbonate ions enter RBC ◦Combine with hydrogen ions ◦Form carbonic acid (H 2 CO 3 ) ◦Carbonic acid splits to form water + CO 2 ◦Carbon dioxide diffuses from blood into alveoli

14 © 2012 Pearson Education, Inc. (b) Internal respiration in the body tissues (systemic capillary gas exchange) Oxygen is unloaded and carbon dioxide is loaded into the blood. Tissue cells Loading of CO 2 Unloading of O 2 Water Plasma Carbonic acid Bicar- bonate ion Systemic capillary Red blood cell O2O2 CO 2 CO 2 + H 2 O H 2 CO 3 H + + HCO 3 _ HbO 2 Hb + O 2 Figure 13.11b

15 Mechanics of Breathing (Pulmonary Ventilation) Two phases ◦Inspiration = inhalation – diaphragm contracts  Flow of air into lungs ◦Expiration = exhalation – diaphragm moves superiorly (up) relaxes  Air leaving lungs

16 © 2012 Pearson Education, Inc. Inspired air: Alveoli of lungs: Pulmonary veins Blood leaving lungs and entering tissue capillaries: Systemic arteries Tissue cells: Blood leaving tissues and entering lungs: External respiration Pulmonary arteries Alveolar capillaries Heart Tissue capillaries Systemic veins Internal respiration O2O2 CO 2 O2O2 O2O2 O2O2 O2O2 O2O2 O2O2 Figure 13.10

17 Neural Regulation of Respiration Activity of respiratory muscles is transmitted to and from the brain by phrenic and intercostal nerves Neural centers that control rate and depth are located in the medulla and pons ◦Medulla—sets basic rhythm of breathing and contains a pacemaker called the self-exciting inspiratory center ◦Pons—appears to smooth out respiratory rate

18 © 2012 Pearson Education, Inc. Pons centers Medulla centers Afferent Impulses to medulla Breathing control centers stimulated by: Efferent nerve impulses from medulla trigger contraction of inspiratory muscles Brain Breathing control centers Intercostal nerves Phrenic nerves CO 2 increase in blood (acts directly on medulla centers by causing a drop in pH of CSF) Nerve impulse from O 2 sensor indicating O 2 decrease CSF in brain sinus O 2 sensor in aortic body of aortic arch Intercostal muscles Diaphragm Figure 13.12

19 Non-Neural Factors Influencing Respiratory Rate and Depth Chemical factors: CO 2 levels ◦The body’s need to rid itself of CO 2 is the most important stimulus ◦Increased levels of carbon dioxide (and thus, a decreased or acidic pH) in the blood increase the rate and depth of breathing ◦Changes in carbon dioxide act directly on the medulla oblongata ◦Changes in oxygen concentration in the blood are detected by chemoreceptors in the aorta and common carotid artery ◦Information is sent to the medulla

Download ppt "Respiratory System In simple animals, like Platyhelminthes (flatworms), respiration is done by diffusion of oxygen. In annelids, oxygen diffuses from moist."

Similar presentations

Ads by Google