Download 7.2 Breathing and Respiration

Breathing and Respiration
Breathing and Respiration
¬ Movement of air in and out of the lungs is dependant on the changing air pressure inside our chest (thoracic) cavity
¬ Inspiration occurs when the respirator center in the medulla oblongata sends an excitatory nerve impulse to the diaphragm, the muscles, and the rib cage
¬ As the muscles between the rib cage contract the diaphragm lowers and the ribs move upwards and outwards Try this!
¬ Stand up
¬ Take a deep breath in, what do you notice?
¬ Breathe slowly out, what do you notice? ¬ What happens to your body – what structures are involved?
¬ The lungs then expand, creating a partial vacuum
¬ Since the air pressure is greater outside the thoracic cavity –
air is moved into the lungs – inspiration
¬ The respiratory center now stops sending impulses to the diaphragm and muscles of the rib cage
¬ As the diaphragm relaxes it resumes its dome shape and the ribs retract
¬ This now increases the air pressure in the cavity – air now moves out of the lungs!
¬ Under normal conditions the concentrations of the oxygen in the inhaled air is greater than the concentration of oxygen in the blood of the capillaries entering the lung area
¬ In contrast, carbon dioxide concentrations is greater in the blood than inhaled air
¬ Oxygen diffuses across the capillary wall into the bloodstream, and carbon dioxide move from the capillaries across the alveoli in the lungs Respiratory Volumes
¬ Regular breathing does not fully expand your lung capacity.
¬ Think of when you exert yourself with exercise, what happens with your breathing –what happens with your lung capacity? What happens when you are sick with a cold? How does this effect your breathing? ¬ In response your body automatically will let you know when it needs more oxygen – you want to take deep breaths in, as the more oxygen you can take in the better it is for your body Measuring your Lung Capacity
¬ A spirograph is a device that measures the air that moves in and out of your lungs with the breathes you take!
¬ You should be able to define the following terms:
¬ Tidal volume, ¬ Inspiratory reserve volume
¬ Expiratory reserve volume and
¬ Residual volume
External Respiration
¬ Oxygen and Carbon dioxide will diffuse to areas of lower concentration
¬ When fresh air is in the alveoli, oxygen will diffuse into the blood of the capillaries and carbon dioxide will diffuse out of the blood into the air
¬ Diffusion requires a wet membrane of the alveoli wall which can facilitate the movement of oxygen into the blood
¬ Diffusion is not always enough to transfer all the oxygen needed in the body. 30 % usually occurs by facilitated diffusion
¬ Blood in the capillaries will have an increased amount of carbon dioxide in it compared to the alveoli ¬ It returns from the body tissues
¬ The carbon dioxide will diffuse INTO the alveoli from the capillaries
¬ Once the gasses have been exchanged it begins its journey to the heart and to the tissue cells
Internal Respiration
¬ The exchange of oxygen and carbon dioxide from the blood into cells/tissues in the body
¬ Oxygen will diffuse out of the blood into the cells with low oxygen concentration
¬ Carbon dioxide will do the reverse
¬ Hemoglobin carries 99% of the oxygen in the blood
¬ In the blood flow, most carbon dioxide is in the form of a bicarbonate ion