Lecture 19 - The Respiratory System Flashcards
what are the functions of the respiratory system?
- exchange of gas between the atmosphere and the blood
- filtration
- temperature regulation
- humidification of air
- olfaction (sense of smell)
- production of sound
what is the arbitrary boundary between the upper and lower parts of the respiratory system?
the vocal cords
what are the two portions of the respiratory system?
conducting and respiratory
contains all the vessels that carry air to the sites of gas exchange
the conducting portion of the respiratory system
contains the sites of gas exchange with the blood
the respiratory portion of the respiratory system
list the nine main portions of the upper respiratory system
- external nares (nostrils)
- nasal vestibule
- conchae
- internal nares
- nasopharynx
- eustachian tube
- oropharynx
- epiglottis
- laryngopharynx
the site of air humidification, filtration, and warming
conchae
two holes at the back of the conchae which serve as the connection between the nasal cavity and pharynx
internal nares
an opening in the nasopharynx which equalizes pressure in the middle ear
eustachian tube
what are the three main functions of the upper respiratory system?
- allows movement of air in and out of the body
- warms and humidifies air
- trap particulates and pathogens
closure of the epiglottis is complex, but upward movement of _____ and posterior movement of _____ are important
the larynx, the tongue
true or false: the vocal cords close while swallowing
true
the midline tube with stiff cartilage rings that prevents collapse
the trachea
the site where blood vessels, lymphatics, nerves, and bronchi enter and leave the lungs
the hilum
the structures that meet at the hilum in the lungs form:
the root of the lungs
why do all of the vessels in the lung enter and exit through the same spot?
leaves the lungs free for movement
how many lobes are present in the right lung and what are their names?
three lobes (superior, middle, and inferior)
how many lobes are present in the left lung and what are their names?
two lobes (superior and inferior)
where is the apex of the lungs located?
at the top point
true or false: the base of the lungs are flat
false: they are concave and mould to the shape of the diaphragm
how many fissures does the right lung have, what are their names, and where are they located?
two fissures, the oblique fissure which separates the superior and middle lobes from the inferior lobe, and the middle fissure which separates the superior and middle lobes
how many fissures are present in the left lung, what are their names, and where are they located?
one fissure, the oblique fissure which separates the superior and inferior lobes
which lung contains the lingula and where is it?
the left lung, located underneath the cardiac notch
which lung contains the cardiac notch?
the left lung
true or false: you could remove a lobe from the lung and the rest would still remain functional
true
the serous membrane that covers the lungs
the visceral pleura
the serous membrane that covers the inside of the body wall in the thoracic cavity
the parietal pleura
a small amount of _____ is present between the pleural layers of the lungs
serous fluid
the pleural cavities extend ______ below the inferior border of the lung, giving rise to ______; these allow space for the lungs to ______
~2 rib levels, recesses, expand
do the lungs fully fill the pleural cavity recesses when they expand?
no, this is only a potential space
like the lungs, the pleaural cavities/recesses sits on top of the:
diaphragm
list the major airways in the lungs
- trachea
- primary bronchi
- secondary and tertiary bronchi
- bronchioles
- terminal bronchioles
how many secondary bronchi are in the right lung?
3 (corresponds with the number of lobes)
how many secondary bronchi are in the left lung?
2 (corresponds with the number of lobes)
the trachea is surrounded by specialized C-shaped:
cartilage rings
why are the cartilage rings on the trachea C-shaped and not full rings?
because we don’t want the stiff cartilage to protrude into the esophagus, which is supposed to move around a lot
instead of having cartilage at the back of the trachea, there is a layer of:
smooth muscle
at what point do the airways have no cartilage?
the bronchioles
why is it that bronchioles have smooth muscle instead of cartilage?
easier to expand and contract the airways (better regulated)
do the smaller bronchi have cartilage rings?
no, they have fragmented bits of catrilage
do the respiratory bronchioles have alveoli?
yes, they have sparse alveoli
the alveolar ducts act as the _____ for a cluster of _____
stems, grapes
true or false: alveoli are open to the central space in the alveolar sac (look like a half sphere)
true
why is alveolar tissue so thin?
to maximize the interface between air and blood you need to minimize all the extra stuff
alveoli are capable of _____ and _____, which is important for breathing
stretching, recoiling
what is the purpose of the conducting airways?
warms, moistens, and conducts air
what is the purpose of the respiratory airways?
both conducts air and respires
found in large airways and helps to keep them open
cartilage
tissue that predominates in smaller airways, controlling the diameter of the airways
smooth muscle
predominates in smaller airways and the respiratory portion of the lungs, elastic recoil provides for expiration
elastic fibres
smooth muscle constriction in the bronchioles is caused by:
parasympathetic nerve stimulation
what is the effect of histamine during an asthmatic attack?
histamine (mediator of allergic reactions) release causes spasms and contractions of the already inflamed airways
breakdown of alveolar walls which produces abnormally large air spaces
emphysema
what are the effects of emphysema on the lung?
lowered surface area for gas exchange and reduced elastic fibres
what are the causes of emphysema?
smoking and other irritants such as pollutants and dust
type of epithelium that is found in the nasal cavity, nasopharynx, and large airways
pseudostratified epithelium
what is the function of the cilia in the respiratory system?
moves fluid and debris along to be swallowed or spit out
type of epithelium found in the oropharynx
stratified squamous epithelium
type of epithelia found in the smaller respiratory tubes
simple columnar, simple cuboidal, and simple squamous
what are type I alveolar cells?
very thin cells (simple squamous epithelium) that form the walls of the alveoli
how many plasma membranes does an oxygen molecule cross to pass from air space to bind a hemoglobin molecule in a red blood cell?
five
what are type II alveolar cells?
cells which secrete surfactant and can act as stem cells to regenerate type I and type II alveolar cells
lowers the surface tension of alveolar fluid and prevents alveolar walls from sticking together and collapsing
surfactant
cells which ingest debris in the alveoli
alveolar macrophages
what is the path that alveolar macrophages follow through the lungs?
- enter airways
- become trapped in mucus sheets
- carried toward pharynx by ciliary action
- expectorated or swallowed
where in the lungs are the pulmonary arteries found?
they travel with the airways and branch with the airways
where in the lungs are the pulmonary veins found?
travel in the interlobular connective tissue
where in the lungs are the lymphatic vessels found?
travel in the interlobular connective tissue (like pulmonary veins)
in the lungs, capillaries are often sandwhiched between:
two alveoli (maximizes efficiency)
which muscle are involved in quiet breathing (eupnea)?
external intercostals and the diaphragm
contraction of external intercostals and diaphragm increases the volume of:
the pleural cavity
what drives lung expansion?
negative pressure (from increased volume of the pleural cavity)
relaxation of the external intercostals and diaphragm decreases the volume of:
the pleural cavtiy
when the volume of the pleural cavity decreases, this causes:
exhalation
_____ of the alveoli is also important during exhalation
elastic recoil
what are the muscles of forced inhalation?
- scalenes
- pectoralis minor
- sternoclaidomastoid
how do the accessory muscles help with forced inhalation?
they elevate the rib cage to make the pleural membrane as big as possible
what are the muscles of forced exhalation?
- internal intercostal muscles
- abdominal wall muscles
how do the muscles of forced exhalation work?
they depress the rib cage
contraction of the diaphragm increases the ______ of the thoracic cavity
vertical diameter
the external intercostals lift the ribs ______ and move the sternum ______
superiorly, anteriorly
what is the function of the sternocleidomastoid during forced inspiration?
elevates the sternum
what is the function of the scalenes during forced inspiration?
elevates ribs 1 and 2
what is the function of the pectoralis minor during forced inspiration?
elevates ribs 3-5
