1. 8.2 The Mammalian Respiratory System

2. The Respiratory System
Respiration: The exchange of oxygen & carbon dioxide between an organism & its external environment.
The respiratory system supplies oxygen to cells & removes carbon dioxide.

3. Components of Respiration
Breathing (Ventilation)
External Respiration
Internal Respiration
Cellular Respiration

4. Breathing (Ventilation)
Inhalation: Oxygen is taken in from the external environment.
Exhalation: Carbon dioxide is removed from the internal environment.

5. External Respiration Gas exchange between the alveoli & blood.
Oxygen diffuses into the alveoli & carbon dioxide diffuses out.
The alveoli must be moist to allow for diffusion.
The blood carries the oxygen from the lungs to the body cells.

6. External Respiration

7. Internal Respiration Gas exchange between the blood &the body cells.
Oxygen diffuses out of the blood & carbon dioxide diffuses in.
Allows cellular respiration to occur.

8. Cellular Respiration Occurs in the mitochondria of every cell.
Cells produce energy (ATP) when glucose is broken down in the presence of oxygen.
Byproducts include carbon dioxide & water

9. Anatomy of the Respiratory System
Analogous to an upside-down tree.
Components:
Nose
Nasal & oral cavities
Pharynx
Larynx
Trachea
Bronchi & bronchioles
Alveoli
Respiratory Basics - Learning Activity - Flash Player Installation

10. The Upper Respiratory Tract
Nose
Structure: Two nostrils separated by cartilage and soft bone
Functions: Air that is breathed in through the nose is:
Warmed by heat in the capillaries in the nose
Dampened when it passes over the mucus lining of the nose
Cleaned by cilia that sweep dirt into the mucus
Filtered by hairs that remove large particles

11. Pharynx (throat) Structure: a muscular tube
Function: the pharynx is necessary
for:
a) breathing: the pharynx connects
the 2 nasal passages to the larynx
which leads to the trachea
b) maintaining air pressure: the Eustachain tube is found in the middle ear and opens into the pharynx and is able to equalize the pressure inside the ear to atmospheric pressure
c) Swallowing: during swallowing, the soft palate rises to block the opening to the nose. A small flap of cartilage, the epiglottis, slides closed to cover the entrance to the trachea.

12. Larynx Structure: -the first part of the trachea
- contains tightly stretched cords (vocal cords)
- while breathing they lie against the wall, while speaking they move forward
Function: forcing air over them causes the cords to vibrate and allows us to speak
the loudness is determined by how hard we breathe out
the pitch is determined by how tight the cords are
the quality is determined by amplifiers (mouth, nose, lungs)
N.B. Men have longer vocal cords therefore their voices are lower

13. Trachea
Structure: a 10 cm tube extending from the larynx to the branches of the bronchi
All breathing tubes are held open by C-shaped rings of cartilage that prevent the tubes from collapsing
Function: passage way
for air

14. The Lower Respiratory Tract
Bronchi
Structure: the base of the trachea divides into 2 tubes called bronchi
-one bronchus goes into the left lung and one to the right lung
-inside the lungs, the bronchi branch out into smaller tubes called bronchioles which spread all over the lungs
Function: passageway for air

15. Alveoli
Structure: inside of our two lungs are 300 million air sacs called alveoli, found in clusters at the ends of bronchioles (allows more surface area)
- each alveolus is surrounded by blood capillaries
- each alveolus is covered in a film of moisture
Function: the oxygen in the air that enters the alveoli during inhalation dissolves in the moisture and diffuses into the capillaries
- the O2 is absorbed by molecules of hemoglobin, a pigment in red blood cells, and transported to the heart.
- CO2 dissolved in water, passes from the capillaries into the alveoli to be breathed out
Therefore, this process is called gas exchange, and the two systems involved are the alveoli and the capillaries.

16. Alveoli

17. Lungs Structure: 2 large spongy organs
that fill nearly the entire thoracic
cavity (chest)
- the left lung is slightly smaller
(2 lobes) b/c the heart sits on it,
whereas the right lung has 3 lobes
- the lungs contain the bronchi, bronchioles, alveoli, and capillaries
- enveloped in layers of tissue called pleura
Function: expand and contract to fill up with gas

18. Structure: a membrane (sac) that covers the lungs
Pleura
Structure: a membrane (sac) that covers the lungs
- between the pleura and the lungs is a fluid that acts as a lubricant
Function: applies pressure equally to all parts of the lungs allowing inhalation and exhalation
Animation: The Pleural Membranes

19. Pleurisy: Inflammation of the pleura that causes when you take a breath or cough; the smooth lining of the lungs becomes rough
Pleural effusion: fluid collecting around
the lungs; resulting
from TB infections

20. How is O2 taken up?
Oxygen diffuses to the cells of the capillaries, to the blood plasma, and then across the cell membranes of red blood cells
In the red blood cells, the oxygen forms a bond with hemoglobin.
Hemoglobin + O2  oxyhemoglobin (HbO2 -)
The red blood cells circulate rapidly in the bloodstream transporting oxygen to all body cells. (A very small amount of dissolved O2 is carried in blood plasma)

21. How is CO2 removed?
Diffusion from cells to the blood ~ 9% is held in the plasma
About 27% attaches to hemoglobin and is carried by RBCs to lungs
64% combines with water to form bicarbonate (HCO3) and hydrogen ions (H+)
CO2 + H2O  H2CO3
H2CO3  H+ + HCO3

22. Hydrogen ions are very reactive and can be fatal in high concentrations therefore they must be removed
The H+ is taken up by oxyhemoglobin. When this happens, the oxygen is released by the oxyhemoglobin and goes into the cells to be used for cellular respiration.
The H+ then react with HCO3 releasing CO2 and H2O which are both released by the lungs.
Respiratory system | Flash simulation, Animation, Illustration, Picture, Diagram