Flashcards in 1. Introduction and anatomy of lungs, airways and blood supply Deck (104):
what are the main functions of respiratory system? (4)
1. gas exchange (O2 added to blood from air and Co2 is removed from blood into the air)
2. acid-base balance (regulation of body pH)
3. protection from infection
4. communication via speech
what is the optimum pH in the extracellular fluid?
pH 7.4 ("magic" number)
what is an example of the respiratory system protecting the body from an infection?
-Mucus can trap large particles from air that can destroy sensitive tissues in lungs e.g. alveoli which are very delicate and can become damaged easily
what is the name of the tiny hairs which line the respiratory tract?
cilia (pseudostratified columnar layer)
how is speech produced? (in simple terms)
Air moves through the larynx and over the vocal cords where vibration occurs
speech can only be produced during which stage of breathing?
Expiration (breathing out) only
Why is gas exchange so important?
NEED TO PRODUCE ENERGY
- cells respire producing ATP which is essential for life, maintain energy supply in the body to keep it alive
-O2 is burned, energy is released and CO2 is produced as a waste product
what two systems work closely together to allow the movement of gases between the air and the body's cells?
Cardiovascular and respiratory systems
what 2 things is the cardiovascular system responsible for?
- transporting oxygen to tissues
- transporting carbon dioxide away from tissues
where does internal respiration occur? what is it?
-Inside cells (also called cellular respiration)
- production of ATP at a molecular level
where does external respiration occur? what is it?
-occurs OUTSIDE the cell
-it's the bulk movement of air from environment into tissues
which of the 2 types of respiration requires the integration of the respiratory and cardiovascular systems?
what type of blood does the pulmonary artery contain?
what direction in relation to the heart does the pulmonary artery travel in?
AWAY from the heart (A in artery for away)
what type of blood does the pulmonary vein contain?
what direction in relation to the heart does the pulmonary vein travel in?
TOWARDS the heart
relating to function, what is the correlation between systemic and pulmonary circulation?
they are the opposite of each other
what are the two main circulatory paths in the cardiovascular system?
- systemic circulation
what is systemic circulation?
circuit through the rest of the body to provide oxygenated blood to tissues
what is pulmonary circulation?
circuit of blood through the lungs where blood is oxygenated by delivering CO2 to the lungs and picks up O2
Usually, arteries carry what type of blood?
Usually, veins carry what type of blood?
what two blood vessels are an exception to the rule which is specific to oxygenated and deoxygenated blood being carried in specific vessels?
-pulmonary artery (carries DEoxygenated blood)
-pulmonary vein (carries oxygenated blood)
At how many points does gas exchange occur at?
at 3 points
what are the 2 points at which gas exchange occurs?
1. between lung and blood in capillaries at alveolar level; O2 moves from inspired air to blood and CO2 moves from blood to air which is then expired (pulmonary circulation)
3. between blood/capillaries and cells (systemic circulation; O2 moves from blood to cells and CO2 moves from cells to blood
what is created by the constant levels of gas traveling in and out of cells forming a balance of gas exchange?
a concentration gradient
what does rate and depth of breathing speed up? (2)
1. substrate (O2) acquisition
2. waste disposal (CO2)
what does heart rate and force of contraction speed up? (2)
1. substrate delivery to muscle via blood
2. waste removal via blood
why does gas exchange only occur at alveoli level?
because bigger blood vessels like veins and arteries are too thick to allow gases to pass through them
in a steady state, what is the relationship between the net volume of O2 or CO2 exchanged in the lungs per unit time and new volume exchanged in tissues?
net volume of O2 or CO2 exchanged in the lungs per unit time = the net volume exchanged in tissues
what would happen if the net volume of O2 and CO2 exchanged in the lungs per unit time did not equal the net volume exchange in tissues?
gas build up in the circulation could occur which could hamper gas exchange
what is the average volume of O2 and CO2 exchanged per minute?
- 250ml oxygen exchanged (consumed)
- 200ml carbon dioxide exchanged (produced)
what is the average breathing rate at rest?
10-20 breaths/ min
what is the average breathing rate at maximum exercise in adults?
what are the main 7 components of the respiratory system?
where is the pharynx situated?
makes up part of the throat immediately posterior to the nasal cavity
what is the role of the pharynx?
passageway leading from the mouth and nose to the oesophagus and the larynx
-permits passage for swallowed liquids and solids (digestive system)
-conducts air to and from the trachea (respiratory system)
what happens to the air in the nose?
air enters body through the nose where cilia and mucus trap particles and warm and moisten the air
what happens in the trachea?
Air moves from the pharynx down trachea into lungs through bronchi.
what is the trachea made up of?
stiff rings of cartilage that supports and protects it, as well as keeps the trachea open
what is the texture of the lungs?
soft and spongy (due to many thousands of tiny hollow sacs that compose them) which allow for efficient absorption of gas
what is the epiglottis?
small flap of tissue that folds over the trachea and prevents food from entering it during swallowing
what is the larynx?
"voice box", contains vocal cords which vibrate to produce sound
what is the role of the bronchus?
air moves from the trachea into either left or right bronchus which leads inside the lungs
Up until which structure do the digestive and respiratory systems split into two (up to that point they shared the same canals)?
at larynx (they split into two)
what is included in the upper respiratory tract? (4)
(anything from larynx and above)
what is included in the lower respiratory tract? (3)
(anything enclosed in the thorax bounded by ribs, spine and diaphragm)
why is the air entry through the nose more efficient than through the mouth?
- humidification process is quicker ( air can be warmed humidified and moistened so it doesn't irritate the sensitive airways)
most of the time, what position is the epiglottis in?
It's open; to allow easier movement of air but as soon as swallowing occurs, muscles around epiglottis contract and "close" the flap preventing fluid and food from entering the lungs
how many secondary bronchi are there in the right lung?
how many secondary bronchi are there in the left lung?
how many fissures does the right lung have and what are they?
2 fissues; oblique and horizontal
how many fissures does the left lung have and what are they?
1 fissure; oblique fissure
how many lobes does the right lung have and what are they?
3 lobes; superior lobe, middle lobe and inferior lobe
how many lobes does the left lung have and what are they?
2 lobes; superior lobe and inferior lobe
what does the falciform ligament do?
attaches the liver to the anterior (ventral) body wall
what membrane surrounds the heart?
why is the left lung slightly smaller than the right?
because of the space for the heart on the left lung which shares its thoracic space with the heart
why is the pleural space bigger than cadavers?
because the lungs have collapsed (usually it's a very small space)
why are aspirated foreign bodies more commonly lodged in the right bronchi than the left?
right bronchi has a trajectory closer to an obtuse angle and is more vertical than the left (which is more acute)
what do cartilaginous rings around the trachea and bronchi ensure?
They ensure the airway is maintained unobstructed, open, stable and patent
do bronchioles contain cartilaginous rings?
what maintains the patency of bronchioles?
forces of the lungs which are maintained at a constantly expanded state (maintained by physical forces of the thorax)
what happens to the diameter of branches as you move down the respiratory tree?
diameter gets smaller
what relationship is there between diameter of a branch and resistance to airflow?
as diameter DECREASES, resistance to airflow INCREASES
Each bronchus branches how many more times before finally terminating in a cluster of alveoli?
what shape is the cartilage around the trachea and bronchi?
C-shaped (semi-rigid tubes)
at which respiratory structure does gas exchange occur only?
alveoli (respiratory zone)
what has a much bigger surface diameter; the trachea or alveoli?
what has a much bigger cross-sectional area; the trachea or alveoli?
if contraction of bronchial smooth muscle decreases diameter, what happens to resistance?
if relaxation of bronchial smooth muscle increases diameter, what happens to resistance?
in which structure is the resistance the greatest?
in the trachea
what extensive network covers the alveoli?
capillary network (which are receiving blood from pulmonary arteries and veins for O2 intake or CO2 excretion)
what are alveoli covered in?
elastic fibres which are critical in breathing (they stretch during inspiration)
Is energy put into inspiration or expiration?
Energy is only put into inspiration as expiration happens passively (automatically)
what are the 3 types of cells which exist in the alveoli?
1. type 1 alveolar cells (pneumocytes)
2. type 2 alveolar cells (pneumocytes)
3. alveolar macrophages
what do type 1 alveolar cells do? (pneumocytes)
very thin cells of resp. system in alveoli which allow GAS EXCHANGE
what do type 2 alveolar cells do? (pneumocytes)
have a specialist function by synthesising surfactant (substance which tends to reduce the surface tension of the liquid it is dissolved in)
what do alveolar macrophages do?
ingest foreign material that reaches the alveoli
why are there no elastic fibres between capillaries and alveolar cells?
this would impede/prevent gas exchange (they are only found around alveoli to stretch them as they fill with air during inspiration)
which cell in alveoli are capillaries attached to?
to Type 1 cells (pneumocytes)
if the lungs were stretched out and flattened, how big would its total SA be?
size of a tennis court (which is compacted into 2 large "coca cola bottle" volumes)
what are conducting airways?
-all airways which are NOT alveoli
- contain dead space
what type of circulation are nutritive blood vessels a part of?
does pulmonary circulation provide nutrients to the lung tissue?
NO- pulmonary circulation (pulmonary arteries and veins) are only involved in delivery of O2 or removal of CO2
what structure is last to be lost as you move down respiratory tract?
what do sub-epithelial glands produce?
Mucus as well as other substances which keep the airway and resp. tract moist
where is smooth muscle only found?
around the bronchioles
where are elastic fibres only found?
around alveoli (they recoil)
what is the anatomical dead space?
the air in the upper airways which does not participate in gas exchange
why are alveoli a perfect structure for gas exchange?
they have very thin walls and a huge surface area for max. gas exchange
what is the type of epithelium lining the resp. tract?
pseudo-stratified, ciliated and columnar
what main structures line the resp. tract? (6)
- epithelium (pseudo-stratified, ciliated, columnar)
-blood vessels (nutritive)
what happens during the progression from nose to alveoli?
- epithelium becomes more squamous
- cilia is lost
- mucous cells are lost (before cilia)
what is lost first as you move from nose to alveoli, the cilia or the mucous cells?
mucous cells are lost first (before cilia)
what is the function of mucous?
- moistens the air
- traps particles
-provides large SA for cilia to act on
what 2 structures produce mucous?
1. goblet cells
2. sub-epithelial glands
where do alveolar macrophages escape to? (2)
pharynx and lymph nodes
how much of the alveolar surface do type 1 pneumocytes take up?
97% alveolar surface
what is the epithelium of type 1 pneumocytes?
simple squamous epithelium (for max. gas exchange)
what do type 2 pneumocytes help do?
what does surfactant do? (2)
-reduces surface tension at alveolar surface
-reduces the work of breathing