Unit 5 - Breathing PART A & B Flashcards
What are the Respiratory System Main Functions?
- Respiration
- Homeostatic regulation of body pH
- Defends against microbes
- Metabolic functions - modifies arterial concentrations of
chemical messengers - Vocalization
- Sense of smell
Respiration 2 types
a. External respiration
b. Internal respiration
External respiration
involves exchange and transport of oxygen and carbon dioxide:
i. between lungs and atmosphere – involves PULMONARY
VENTILATION (inspiration and expiration)
ii. between alveoli and blood
iii. within the blood – transport from capillaries in the lungs to
capillaries in the systemic tissues and vice versa)
iv. between blood and cells
Internal respiration
= cellular respiration
i. Use of O2 by mitochondria in cells to produce ATP. CO2 is formed as a waste product of this process.
Homeostatic regulation of body pH
by retaining or releasing CO2 by decreasing or increasing respiratory rate.
↑ rate
– clears more CO2 and makes blood less acidic (more alkaline)
↓ rate
- allows CO2 to build up and makes blood more acidic.
Defends against microbes
- MUCOCILIARY ESCALATOR (mucus traps pathogens and beating cilia move the mucus toward the pharynx)
- resident alveolar macrophages phagocytize pathogens and debris in the alveoli.
Metabolic functions
modifies arterial concentrations of chemical messengers
removes and inactivates some messengers/enzymes
• E.g. ~30% of norepinephrine in venous blood is removed
in the lungs.
produces and activates others
• E.g. Angiotensin Converting Enzyme (ACE) produced in the lungs converts angiotensin I into angiotensin II (an important regulator of mean arterial pressure and water balance).
Vocalization
produced by moving air across the vocal cords in the larynx.
Sense of smell
requires inspiration so that scent molecules in the air can enter the nasal cavity and stimulate the olfactory receptors (free nerve endings) in the roof of the nasal cavity.
Respiratory System
consists of structures involved in ventilation of gas exchange
- CONDUCTING SYSTEMS of passages, or AIRWAYS…
- ALVEOLI (ALVEOLUS)…
- Bones & muscles of the thorax (chest cavity) & abdomen that assist in ventilation
Upper Respiratory Tract consists of the:
a. Nasal cavity
b. Mouth
c. Pharynx
d. Larynx
Nasal cavity
warms, humidifies, and filters (nasal hairs) air.
Mouth
alternative route for air entry from the atmosphere. Not as effective at warming/humidifying/filtering as breathing through the nose.
Pharynx
common passageway for food and air
Larynx
contains the vocal cords.
Lungs
- consist of light, spongy tissue whose volume is occupied mostly by air-filled spaces
Lungs
Located…
Located in thoracic cavity which is formed by the vertebral
column, rib cage and associated muscles including the muscles involved in breathing:
i. Diaphragm
ii. External intercostals
iii. Internal intercostals
iv. Sternocleidomastoids
v. Scalenes
Lungs
…associated muscles including the muscles involved in breathing:
i. Diaphragm
ii. External intercostals
iii. Internal intercostals
iv. Sternocleidomastoids
v. Scalenes
Lungs
Air enters the lungs via…
Air enters the lungs via the UPPER respiratory tract (mouth/nasal cavity, pharynx, larynx)) and the LOWER respiratory tract (trachea, bronchi, bronchioles)
Each lung is divided into lobes…
right lung 3 lobes, left lung 2 lobes.
Each lung is surrounded by…
a double layered membrane called the PLEURAL SAC.
Each lung is surrounded by a double layered membrane called the pleural sac. The two layers of the membrane are the:
i. visceral pleura
ii. Parietal pleura