1. Respiratory System
SC.912.L Describe the histology of the respiratory system.
SC.912.L Describe the physiology of the respiratory system including the mechanisms of ventilation, gas exchange, gas transport and the mechanisms that control the rate of ventilation.

2. Introduction
The respiratory system contains a group of passages that remove particles from incoming air and transport it from outside the body into and out of the lungs
Respiration: exchange of gases from atmosphere into the body
Cellular respiration: cell’s use of oxygen and carbon dioxide

4. Organs of the Respiratory System
Nose
Nasal Cavity
Sinuses
Pharynx
Larynx
Trachea
Bronchial tree
Lungs

5. Nose Nostrils: air to come in and to leave
Has hairs which help trap particles in the air

6. Nasal Cavity Hollow space behind the nose
Divided into two sections by the nasal septum
Contain mucous membranes
Function of Mucous Membranes:
Warms, filters, and moistens incoming air
Traps particles from air and transports to pharynx to be swallowed

7. Paranasal Sinuses
Spaces open into the nasal cavity that have mucous membranes
Function is to reduce weight of skull and to serve as resonant chambers which affect quality of voice

8. Pharynx (throat) Food travels from oral cavity to pharynx to esophagus
Air travels from nasal cavity to pharynx to the larynx

9. Larynx Where air passes to go in and out of the trachea
Vocal cords are located here also
Composed mainly of muscles and cartilage
Vocal cords produce sounds causing air ro vibrate and passes between the cords
The glottis and epiglottis helps prevent food and liquid entering the trachea

10. Larynx and Epiglottis

11. Trachea (windpipe)
Flexible tube that is located in front of the esophagus and splits into right and left bronchi
Also includes cilia to capture particles in the air
Tube of trachea has 20 c-shaped pieces of cartilage to prevent it from collapsing

12. Trachea

13. Bronchial Tree
Trachea branches off to the right and left primary branches
Bronchi have similar structure to trachea
Air passes through bronchial tree and particles are still being absorbed
Contain alveoli- provides structure so gas exchange can occur
Many alveoli in bronchial tree and lungs
Approximately 300 million alveoli

14. Bronchus and Bronchial Tree

15. Alveoli

16. Lungs Soft, spongy cone shaped organs located in the thoracic cavity
Takes up much of the space in the thoracic cavity and attached to bronchi and blood vessels
Visceral pleura- attached to surface of the lung
Parietal pleura- lines the thoracic cavity, in between each membrane there is serous fluid to reduce friction when breathing
Right lung is larger than left

17. Structure of Lung Bronchial tree branch Blood vessels
Connective tissue
Alveoli
Nerves

18. Next Class…
We will cover the rest of the notes
Lung Capacity Lab

19. Breathing Mechanism
Inspiration- inhaling
Expiration- exhaling

20. Pressure Gradients
When you inhale, your diaphragm lowers, creating a low pressure area in your lungs (greater volume).
Because air moves to the area of least pressure, air goes into your lungs.
When you exhale, the opposite happens.
Your diaphragm raises, decreasing the volume of your lungs and creating a high pressure area.
The air is then forced out of your lungs by the increased pressure.

21. Concentration Gradient
Oxygen and Carbon Dioxide move across the alveoli from an area of high concentration to an area of low concentration
Inhaled air is high oxygen (leaves alveoli to enter blood stream to be transported to tissues)
Blood leaving tissues is high carbon dioxide (leaves blood and enters alveoli to be exhaled)

22. Breathing Mechanism Inspiration
Atmospheric pressure force causes air to move into lungs
Inspiration occurs when the pressure inside the alveoli is reduced
Pressure in alveoli is reduced when the diaphragm moves downward giving more room for thoracic cage and expansion of lungs

23. Breathing Mechanism Expiration Due to elastic recoil of tissues
Also aided by the thoracic and abdominal wall muscles

24. Baby’s First Breath
During pregnancy, the baby “breathes” through the umbilical cord attached to the placenta
Mother’s blood circulates through the placenta and oxygenates the baby
Once the baby is born, the alveoli which are filled with fluid, slowly gets replaced by air (which is what the delay is before the baby cries)
Hormonal changes inside the baby cause the alveoli, which are limp, to fill up with air

25. Control of Breathing Normal breathing is rhythmic and involuntary
Respiration Center
Located in brain stem- pons and medulla oblongata

26. Control of Breathing Factors affecting breathing
Chemicals, stretching of lung tissues and emotional stress
Chemosensitive areas are influenced by blood concentrations of Carbon Dioxide and Hydrogen ions, which increases breathing rate
Hyperventilation causes blood carbon dioxide concentration to decrease

27. Air Volumes and Capacities
Normal breathing is called tidal volume (TV)
Approximately the same amount of air that is inhaled also exits.
Inspiratory reserve volume (IRV)- amount of extra air inhaled beyond normal inhalation
Expiratory reserve volume (ERV)- amount of air that can be forced out after normal exhale

28. Air Volume and Capacities
Residual volume (RV)- amount of air that remains after the ERV
Prevents oxygen content in the lungs from fluctuating too much because new incoming air mixes with the residual air.
Allows for continuous oxygen supply even when exhaling

29. Lung Capacities Vital Capacity (VC)= IRV + TV+ ERV
Inspiratory capacity (IC)= TV + IRV
Functional Residual capacity= ERV + RV
Total Lung Capacity= TV + Residual Volume + ERV + IRV