BMSC 208: Final COMPLETE
QUESTIONS & SOLUTIONS
The movement of air between the lungs and the atmospheric environment is formally
referred to as - ANSWER Ventilation
What are the four major functions of the respiratory system? - ANSWER 1. Exchange of
gases bw atmosphere & blood
2. Homeostatic regulation of body ph (either by retaining or expelling CO2 = acid)
3. Protection from inhaled pathogens and irritating substances (from air)
4. Vocalization (movement of air across vocal cords)
What structures are involved in ventilation and gas exchange? - ANSWER 1.
Conducting system or airways (area between atmosphere and exchange epithelium of
lungs)
2. Alveoli (the actual exchange epithelium)
3. Bones/muscles of the thorax/chest cavity (important in ventilation/breathing)
What is the major function of the airways in the respiratory system. - ANSWER connect
lungs to external environment.
What are lungs made of? - ANSWER Mainly made of light spongy tissue (= alveoli)
whose volume is mostly occupied by air-filled spaces
Describe the movement of air once it enters the body. - ANSWER -air enters through
the nasal cavity/mouth
-moves into the pharynx
-enters the larynx (vocal cords)
-flows through the trachea
-trachea extends into the thoracic cavity and divides into two tubes (primary bronchi)
-each primary bronchi enters a lung
-branching of each primary bronchi into smaller and smaller bronchi until bronchioles
-bronchioles then terminate in alveoli
Compare the upper respiratory system and lower respiratory system - ANSWER Upper
respiratory system = structures that are not in the thoracic cavity (nasal cavity, mouth,
pharynx, larynx)
,Lower respiratory system = structures that are in the thoracic cavity (trachea, bronchi,
lungs)
What is the function of the upper airways and bronchi? - ANSWER 1) play important
role in conditioning air before it reaches the alveoli
2) prevent large fluctuations in body temperature
3) reduce chance of pathogens entering
Are the left and right lungs identical? - ANSWER NO
-right lung is larger than left (bc left lung has cardiac notch)
-right lung has three lobes (superior lobe, middle lobe, inferior lobe)
-left lung has two lobes (superior lobe and inferior lobe) + cardiac notch (where apex of
heart rests)
What is the trachea? - ANSWER A single semi flexible tube held open ALWAYS with 15
to 20 cartilage rings (aka windpipe)
What are alveoli? - ANSWER Small sacs that are the actual exchange epithelium
(single epithelial cell layer) in the lungs that allows easy diffusion of gases, between the
blood and the lungs
Where are alveoli located? - ANSWER clustered at ends of bronchioles
How do alveoli maximize gas exchange? - ANSWER 1) heavily vascularized
-80 to 90% alveoli covered
-more capillaries = more gas exchange
2) huge SA
How do the upper airways and bronchi condition the air before it reaches the alveoli? -
ANSWER 1. Warms air to body temperature (37 C) = to prevent large fluctuations in
core body temperature
2. Adds water vapour = to keep the exchange epithelium moist to facilitate gas
exchange/diffusion
3. Filters out foreign material (pathogens, irritating substances) = to prevent diseases
from entering bloodstream
Note: these three processes are more efficient with nose breathing, because the nasal
cavity has a large surface area, rich blood supply, and nasal hair (to trap pathogens) +
,shape of nasal airway causes pathogens to embed in the mucus in the back of the
pharynx, and slide down to the esophagus where they are neutralized in the stomach
Why do humans have a specialized respiratory system? - ANSWER Because we are
multicellular organisms with trillions of cells that aren't directly exposed to the external
environment so we needed way to bring gases into the body and distributing them
through the body
Explain the four step process of external respiration. - ANSWER 1) Ventilation:
movement of air (either into or out of our lungs)
-moving air into the lungs = inhalation/inspiration
-moving air out of lungs = exhalation/expiration
2) Exchanging gases between the lungs and the bloodstream
-O2 enters and CO2 leaves blood
3) Transport of gases in the blood
-O2 = mainly via haemoglobin
4) Exchange between blood and the cells
-O2 enters the cells
-CO2 (from cellular respiration) enters the blood
What system is linked with the respiratory system? - ANSWER Cardiovascular system
-external respiration, requires coordination between respiratory and cardiovascular
systems
-ex. increases in ventilation are matched by increases in blood flow
What is the mechanism through we take air into our body? - ANSWER Bulk flow = you
take in the air, and everything that is mixed in the air (gases, pathogens, etc.)
Principles of bulk flow - ANSWER 1. Flow occurs from area of high pressure to low
pressure.
2. Muscular pump creates the pressure gradients.
3. Resistance mainly influenced by diameter of tubes, through which air is flowing
Note: same principles as bulk flow through CV system
What are the different kinds of respiration? - ANSWER 1. Cellular respiration
-Conversion of the organic molecules/glucose/FAs into ATP, water, and ultimately CO2
via aerobic metabolism
2. External respiration
, -All the processes that lead up to the moment, when oxygen is available for cellular
respiration at the cell-level
-The movement of gases between environment and cells within the body
-four step process
-requires coordination bw respiratory + cardiovascular systems
What is the pleural sac? - ANSWER A double walled sac filled with fluid, that surrounds
each lung; consists of three parts:
1) visceral pleura = layer of the sac connected to the outside surface of the lungs
2) parietal pleura = the other layer that is connected to the inside surface of the thoracic
cavity + diaphragm
3) pleural cavity = the fluid filled space ( = pleural fluid) inside the sac
What is the function of the pleural sac? - ANSWER 1. Creates moist, slippery surface
(so the lungs can move without generating friction)
2. Holds lungs tight to thoracic wall (cohesion of pleural fluid that holds the visceral layer
close to the parietal layer)
3. Keeps lungs in a somewhat expanded/open state
Bronchioles versus bronchi - ANSWER Bronchi still have cartilage on them (in plate
formation however) while bronchioles have smooth muscles (instead of cartilage)
Describe the branching of the airways. - ANSWER -trachea splits into two primary
bronchi, each one entering a lung
-each primary bronchi splits 10 to 12 more times into smaller and smaller bronchi, until
you reach the bronchioles
-each bronchiole divide 12 more times into smaller bronchioles, which eventually end in
a cluster of alveoli (some alveoli are also present in the walls of the bronchioles, directly
connected to the clusters)
-like the branching of the cardiovascular system, there is an increase in total cross-
sectional area as branching increases + air flow velocity decreases as the total cross-
sectional area increases
How is air filtered in the trachea and bronchi/bronchioles? - ANSWER Trachea and
bronchi/bronchioles are lined with epithelial cells (two types):
1. simple ciliated epithelial cells
2. specialized mucus-producing epithelial cells = goblet cells
QUESTIONS & SOLUTIONS
The movement of air between the lungs and the atmospheric environment is formally
referred to as - ANSWER Ventilation
What are the four major functions of the respiratory system? - ANSWER 1. Exchange of
gases bw atmosphere & blood
2. Homeostatic regulation of body ph (either by retaining or expelling CO2 = acid)
3. Protection from inhaled pathogens and irritating substances (from air)
4. Vocalization (movement of air across vocal cords)
What structures are involved in ventilation and gas exchange? - ANSWER 1.
Conducting system or airways (area between atmosphere and exchange epithelium of
lungs)
2. Alveoli (the actual exchange epithelium)
3. Bones/muscles of the thorax/chest cavity (important in ventilation/breathing)
What is the major function of the airways in the respiratory system. - ANSWER connect
lungs to external environment.
What are lungs made of? - ANSWER Mainly made of light spongy tissue (= alveoli)
whose volume is mostly occupied by air-filled spaces
Describe the movement of air once it enters the body. - ANSWER -air enters through
the nasal cavity/mouth
-moves into the pharynx
-enters the larynx (vocal cords)
-flows through the trachea
-trachea extends into the thoracic cavity and divides into two tubes (primary bronchi)
-each primary bronchi enters a lung
-branching of each primary bronchi into smaller and smaller bronchi until bronchioles
-bronchioles then terminate in alveoli
Compare the upper respiratory system and lower respiratory system - ANSWER Upper
respiratory system = structures that are not in the thoracic cavity (nasal cavity, mouth,
pharynx, larynx)
,Lower respiratory system = structures that are in the thoracic cavity (trachea, bronchi,
lungs)
What is the function of the upper airways and bronchi? - ANSWER 1) play important
role in conditioning air before it reaches the alveoli
2) prevent large fluctuations in body temperature
3) reduce chance of pathogens entering
Are the left and right lungs identical? - ANSWER NO
-right lung is larger than left (bc left lung has cardiac notch)
-right lung has three lobes (superior lobe, middle lobe, inferior lobe)
-left lung has two lobes (superior lobe and inferior lobe) + cardiac notch (where apex of
heart rests)
What is the trachea? - ANSWER A single semi flexible tube held open ALWAYS with 15
to 20 cartilage rings (aka windpipe)
What are alveoli? - ANSWER Small sacs that are the actual exchange epithelium
(single epithelial cell layer) in the lungs that allows easy diffusion of gases, between the
blood and the lungs
Where are alveoli located? - ANSWER clustered at ends of bronchioles
How do alveoli maximize gas exchange? - ANSWER 1) heavily vascularized
-80 to 90% alveoli covered
-more capillaries = more gas exchange
2) huge SA
How do the upper airways and bronchi condition the air before it reaches the alveoli? -
ANSWER 1. Warms air to body temperature (37 C) = to prevent large fluctuations in
core body temperature
2. Adds water vapour = to keep the exchange epithelium moist to facilitate gas
exchange/diffusion
3. Filters out foreign material (pathogens, irritating substances) = to prevent diseases
from entering bloodstream
Note: these three processes are more efficient with nose breathing, because the nasal
cavity has a large surface area, rich blood supply, and nasal hair (to trap pathogens) +
,shape of nasal airway causes pathogens to embed in the mucus in the back of the
pharynx, and slide down to the esophagus where they are neutralized in the stomach
Why do humans have a specialized respiratory system? - ANSWER Because we are
multicellular organisms with trillions of cells that aren't directly exposed to the external
environment so we needed way to bring gases into the body and distributing them
through the body
Explain the four step process of external respiration. - ANSWER 1) Ventilation:
movement of air (either into or out of our lungs)
-moving air into the lungs = inhalation/inspiration
-moving air out of lungs = exhalation/expiration
2) Exchanging gases between the lungs and the bloodstream
-O2 enters and CO2 leaves blood
3) Transport of gases in the blood
-O2 = mainly via haemoglobin
4) Exchange between blood and the cells
-O2 enters the cells
-CO2 (from cellular respiration) enters the blood
What system is linked with the respiratory system? - ANSWER Cardiovascular system
-external respiration, requires coordination between respiratory and cardiovascular
systems
-ex. increases in ventilation are matched by increases in blood flow
What is the mechanism through we take air into our body? - ANSWER Bulk flow = you
take in the air, and everything that is mixed in the air (gases, pathogens, etc.)
Principles of bulk flow - ANSWER 1. Flow occurs from area of high pressure to low
pressure.
2. Muscular pump creates the pressure gradients.
3. Resistance mainly influenced by diameter of tubes, through which air is flowing
Note: same principles as bulk flow through CV system
What are the different kinds of respiration? - ANSWER 1. Cellular respiration
-Conversion of the organic molecules/glucose/FAs into ATP, water, and ultimately CO2
via aerobic metabolism
2. External respiration
, -All the processes that lead up to the moment, when oxygen is available for cellular
respiration at the cell-level
-The movement of gases between environment and cells within the body
-four step process
-requires coordination bw respiratory + cardiovascular systems
What is the pleural sac? - ANSWER A double walled sac filled with fluid, that surrounds
each lung; consists of three parts:
1) visceral pleura = layer of the sac connected to the outside surface of the lungs
2) parietal pleura = the other layer that is connected to the inside surface of the thoracic
cavity + diaphragm
3) pleural cavity = the fluid filled space ( = pleural fluid) inside the sac
What is the function of the pleural sac? - ANSWER 1. Creates moist, slippery surface
(so the lungs can move without generating friction)
2. Holds lungs tight to thoracic wall (cohesion of pleural fluid that holds the visceral layer
close to the parietal layer)
3. Keeps lungs in a somewhat expanded/open state
Bronchioles versus bronchi - ANSWER Bronchi still have cartilage on them (in plate
formation however) while bronchioles have smooth muscles (instead of cartilage)
Describe the branching of the airways. - ANSWER -trachea splits into two primary
bronchi, each one entering a lung
-each primary bronchi splits 10 to 12 more times into smaller and smaller bronchi, until
you reach the bronchioles
-each bronchiole divide 12 more times into smaller bronchioles, which eventually end in
a cluster of alveoli (some alveoli are also present in the walls of the bronchioles, directly
connected to the clusters)
-like the branching of the cardiovascular system, there is an increase in total cross-
sectional area as branching increases + air flow velocity decreases as the total cross-
sectional area increases
How is air filtered in the trachea and bronchi/bronchioles? - ANSWER Trachea and
bronchi/bronchioles are lined with epithelial cells (two types):
1. simple ciliated epithelial cells
2. specialized mucus-producing epithelial cells = goblet cells
