Transcript Unit 3 Notes

Unit 3: Circulatory System
(1) Respiration (“Breathing”)
• Includes:
– Movement of air in and out of lungs.
– Gas exchange between blood + alveoli.
– Transportation of oxygen and carbon dioxide via the
blood.
– Gas exchange between blood + tissue cells.
(2) Inspiration
•
1.
2.
3.
4.
Inspiration = Inhalation
(Fill with Oxygen Gas)
Diaphragm contracts
Increase in Thoracic Volume
Decrease in Lung Pressure
Air Moves from High  Low Pressure into the
Lungs
5. Lung Pressure Increases & Equilibrates
• http://www.youtube.com/watch?v=hpgCvW8PRY&feature=related
(3) Expiration
•
1.
2.
3.
4.
Expiration = Exhalation
(Expel Carbon Dioxide Gas)
Diaphragm relaxes
Decrease in Thoracic Volume
Increase in Lung Pressure
Air moves from High  Low Pressure out of
the lungs
5. Lung Pressure Decreases & Equilibrates
(4) Gas Exchange
• Exchange between Oxygen & Carbon Dioxide
• Alveoli =
Part of Respiratory System
– Contain intake of oxygen
– Get rid of carbon dioxide
• Capillaries & Blood =
Part of Cardiovascular System
– Take Carbon dioxide from respiring cells  Alveoli
– Take oxygen from alveoli  cells
• Alveoli covered in Capillaries  Diffusion Across
(5) Oxygen Exchange
– Taken in through respiratory system
– Held in alveoli of lungs
– Higher Concentration of O2 in alveoli than
blood stream  Diffusion into blood stream
– Binds with hemoglobin in red blood cells
– Transported to tissues in need of oxygen
(6) Carbon Dioxide Exchange
– Released from cells during cellular respiration
– Binds with hemoglobin AND stored in plasma as
carbonic acid/bicarbonate
– Higher Concentration of CO2 in blood than in alveoli
 Diffusion out of blood stream into lungs
– Release through respiratory system
• http://www.youtube.com/watch?v=DoSTeh
S7iq8
(7) Regulation of Respiration
• Controlled by the Medulla & Pons:
– Medulla sets basic respiration rate
– Pons maintains inspiratory + expiratory rhythm set by
medulla
– Pons also increases/decreases rates during various
circumstances
• Alveoli & Bronchioles lined with stretch receptors:
– Trigger expiration during over-inspiration
– Common during heightened emotion or physical activity
• Lack of Oxygen  Large Gasps / Yawning
– Impulse sent to brain to cause intake of oxygen
– Result = Gasp for air
(8) Respiratory Rate
• Should be approx. 15 respirations/minute.
• Factors Impacting Rate:
– Physical Activity & Changes in Cellular Respiration
– Conscious Control
– Changes in emotion + environmental stimuli
– Levels of carbon dioxide + oxygen in blood:
• Carbon dioxide concentrations monitored by pH
• Oxygen concentrations monitored by chemoreceptors in
aortic arch