1. Respiratory System

2. RESPIRATORY STRUCTURES

3. OUR GOALS TODAY... Identify and give functions for each of the following: – nasal cavity– pharynx – larynx– trachea – bronchi– bronchioles – alveoli– diaphragm and ribs – pleural membranes– thoracic cavity Explain the roles of cilia and mucus in the respiratory tract Explain the relationship between the structure and function of alveoli

4. Upper Respiratory Tract Nostrils – mucousal cell layer Pharynx – common passage for air and food Epiglottis

5. Trachea Connects pharynx to smaller air passageways C-shaped rings of cartilage – Keep Trachea Open – Structural Support Larynx (vocal box) Vocal Cords are composed to 2 tendons that adjust the pitch of sounds

6. Bronchi Trachea branch into bronchi Cartilage Present Bronchi branch further into bronchioles Bronchiole Tree End at Alveoli

7. Alveoli Blind sac-like ends on bronchioles Millions per lung

8. Alveoli Highly specialized: – Walls only 1 cell thick to help with the diffusion of gases – Coated with lipoproteins in their inner surface to sustain surface tension (required so they don`t collapse when you exhale) – Stretch receptors – nerve endings that respond to stretch (send message to medulla oblongata that signals you to exhale when alveoli are full) – Highly vascularized with pulmonary capillaries for gas exchange and to prevent alveoli from drying out

10. REMEMBER OUR GOALS TODAY... Identify and give functions for each of the following: – nasal cavity– pharynx – larynx– trachea – bronchi– bronchioles – alveoli– diaphragm and ribs – pleural membranes– thoracic cavity Explain the roles of cilia and mucus in the respiratory tract Explain the relationship between the structure and function of alveoli

11. Assignment Describe the location and function of the following structures: – Diaphragm and Ribs – Thoracic Cavity – Pleural Membrane

12. MECHANICS OF BREATHING

13. Our Goals Today... Describe the interactions of the following structures in the breathing process: – Respiratory centre in the medulla oblongata – Lungs – Pleural membranes – Diaphragm – Intercostal (rib) muscles – Stretch receptors Compare the processes of inhalation and exhalation Explain the roles of carbon dioxide and hydrogen ions in stimulating the respiratory centre in the medulla oblongata Explain the roles of oxygen, carbon dioxide, and hydrogen ions in stimulating carotid and aortic bodies

14. Medulla Oblongata Sensitive to the concentration of CO 2 and H + in the blood plasma Considered toxins and must be excreted When concentrations get high enough the medulla oblongata sends nerve impulses to the diaphragm and intercostal muscles

15. Diaphragm & Intercostal Muscles Diaphragm – muscles located below the lungs – Moves down when it contracts Intercostal Muscles – between ribs – Moves rib cage up and out during contraction These muscle contractions increase the volume of the thoracic cavity – creates a vacuum effect drawing air in (negative pressure) Contraction requires ATP

17. Pleural Membrane Double membrane 1 surrounds the lungs 1 lines the inside of the thoracic cavity 2 functions: – Allow lungs to slide in the chest cavity easily – Seals thoracic cavity (so negative pressure can develop for inhalation) Pneumothorax

18. Exhalation Stretch receptors detect when the alveoli are stretched open This signals the Medulla Oblongata to direct the diaphragm and intercostal muscles to relax Diaphragm moves upwards and ribcage moves in and down – causing exhalation

20. Chemoreceptors Located in the aortic arch and carotid arteries – Sensitive to oxygen levels in the blood – If it gets too low then it will signal inhalation Secondary mechanism – Blood Plasma CO 2 and H + primarily cause inhalation

21. Remember Our Goals... Describe the interactions of the following structures in the breathing process: – Respiratory centre in the medulla oblongata – Lungs – Pleural membranes – Diaphragm – Intercostal (rib) muscles – Stretch receptors Compare the processes of inhalation and exhalation Explain the roles of carbon dioxide and hydrogen ions in stimulating the respiratory centre in the medulla oblongata Explain the roles of oxygen, carbon dioxide, and hydrogen ions in stimulating carotid and aortic bodies

22. GAS EXCHANGE

23. Our Goals Today... Describe the exchange of carbon dioxide and oxygen during internal and external respiration, including – location of exchange – conditions that favour exchange (e.g., pH, temperature) Explain the roles of oxyhemoglobin, carbaminohemoglobin, reduced hemoglobin, bicarbonate ions, and carbonic anhydrase in the transport of carbon dioxide and oxygen in the blood Write the chemical equations for internal and external respiration

24. Air is Conditioned in 3 Ways 1)Thoroughly Cleaned – Nose hairs and mucus of nasal passageways – Mucosal lining and cilia along trachea and bronchi (trap and move anything other than gases and move them up to mouth) 2)Temperature adjusted to around 37 ˚ C 3)Becomes saturated with water

25. Overview Breathing (Inhaling and Exhaling) External Respiration (gases exchanged between the lungs and blood) Internal Respiration (gases exchanged between the blood and tissues) Cellular Respiration (ATP production by mitochondria)

26. External Respiration In the alveoli blood is around 37˚C and has a pH of 7.4 – Under these conditions hemoglobin freely combines with oxygen Hemoglobin has 4 binding sites for oxygen (oxyhemoglobin – HbO 2 ) HbO 2 delivers O 2 to tissues for internal respiration

28. Internal Respiration At the tissues the blood is around 38˚C and has a pH of 7.35 – These conditions cause HbO 2 to release O 2 as blood enters the capillary beds O 2 diffuses into tissues with water (capillary fluid exchange)

29. Internal Respiration At the venule side of the capillary recall that water re-enters the blood with CO 2 due to osmotic pressure pH and temperature conditions result in most of the CO 2 reacting with H 2 O CO 2 + H 2 O → [H 2 CO 3 ] → HCO 3 1- + H 1+ – Catalyzed by Carbonic Anhydrase – Bicarbonate ions act as a buffer throughout the body – Hydrogen ions are transported in hemoglobin (HHb) so that they don`t change the pH of the blood

30. Internal Respiration Rest of the CO 2 either bonds to hemogloblin (carbaminohemoglobin /HbCO 2 ) OR is transported as dissolved gas in the plasma Blood enters the veins and goes through the heart and the pulmonary circuit back to the lungs

31. Back at the Lungs... Blood returning to the alveolar capillaries is transporting bicarbonate ions and some carbon dioxide gas Hemoglobin is transporting either H + or CO 2 Temperature is slightly lower and pH is slightly higher causing hemoglobin to release H + and CO 2 Enzyme carbonic anhydrase catalyzes the reverse reaction HCO 3 1- + H 1+ → [H 2 CO 3 ] → CO 2 + H 2 O

33. The end of the story... Carbon dioxide diffuses into the alveoli and is exhaled Some water is also exhaled Hemoglobin is free to bind to oxygen

34. Remember Our Goals Today... Describe the exchange of carbon dioxide and oxygen during internal and external respiration, including – location of exchange – conditions that favour exchange (e.g., pH, temperature) Explain the roles of oxyhemoglobin, carbaminohemoglobin, reduced hemoglobin, bicarbonate ions, and carbonic anhydrase in the transport of carbon dioxide and oxygen in the blood Write the chemical equations for internal and external respiration