Respiratory Flashcards
What is the primary function of the respiratory system?
swapping O2 for CO2
What is respiration?
the process of bringing O2 from outside air to all of the body’s cells and carrying CO2 out in the opposite direction
What is external respiration?
exchange of O2 and CO2 between the air inhaled into the lungs and the blood flowing through the pulmonary cappilaries
Where does external respiration occur?
in the lungs
What is internal respiration?
exchange of O2 and CO2 between the blood in the capillaries and all other cells/ tissues of the body
Where does internal respiration take place?
all over the body
What are other functions of the respiratory system?
voice production, temperature regulation, acid-base balance, olfactory sensation (smell)
How many divisions of respiratory system?
2
What is the upper respiratory tract?
nasal passages, pharynx, larynx, trachea
What is the lower respiratory tract?
bronchi, alveoli
What are the openings in the nose called?
Nares
Where do the nares lead to?
nasal passages
What divides the nasal passages into right and left?
nasal septum
What separates the nasal passage from the mouth?
the hard and soft palate
Tubes are convoluted and full of twists due to what?
the nasal turbinates (conchae)
What are turbinates?
scroll like bones converted with nasal epithelium that occupy moist of the lumen
There are 2 sets per passage, which are?
a dorsal and ventral turbinate
When divided the turbinates divide the passage into 3 main passageways known as what?
nasal meatus
Ventral nasal meatus is found between
ventral turbinate and the floor of the nasal passage
Middle nasal meatus is found between
ventral and dorsal turbinates
dorsal nasal meatus is found between
dorsal turbinate and roof of nasal meatus
Turbinates are lined with what?
pseudostratified ciliated columnar epithelium
Moves debris toward ___________
the pharynx
What do these cells have that produce mucous to bind up debris?
goblet cells
Turbinates hold the what?
smell receptors
What is the main function of turbinates?
to condition, humidify, and filter the air
What are sinuses (paranasal)?
outpouches of the nasal passages that are contained within spaces in certain skull bones
Each sinus is named for the ____________
bone that houses it
Most animals have ____________
2 frontal sinuses and 2 maxillary sinuses
Some animals have extra sinuses, which are?
sphenoidal and ethmoidal sinuses (horses)
They (all sinuses) have the same __________
epithelial lining
What do the sinuses move?
debris and mucous down into the nasal passages
What is the pharynx?
-throat
-nasal passages lead here
The pharynx is the common passageway for what?
respiratory and digestive systems
Rostral end ——-> (of the pharynx)
soft palate divides the pharynx into the dorsal nasopharynx (respiratory) and the oropharynx (digestive)
Caudal end opens dorsally into the ———> (pharynx)
esophagus (digestive)
Caudal end opens ventrally into the ——-> (pharynx)
trachea (respiratory)
Pharynx Must allow for both _______________
breathing and swollowing
What controls the actions of muscles around the pharynx?
delicate reflexes
Breathing ——-> (pharynx)
pharynx just stays open
Swallowing ——->
larynx and pharynx work together to prevent choking
What is the larynx?
-voice box
-a short irregular tube that connects the pharynx with the trachea
What takes place here? (larynx)
voice production (phonation)
What is the larynx made up of?
segments of cartilage that are connected by muscle
Larynx is supported by what bone?
hyoid bone
Major cartilages in common animals:
a single epiglottis
paired arytenoid cartilages
single thyroid cartilage
single cricoid cartilage
What 2 cartilages are clinically most important?
epiglottis and arytenoid cartilages
What is the epiglottis?
leaf shaped and is most rostral of laryngeal cartilages
Position of epiglottis:
projects forward from the ventral portion of the larynx and its bluntly pointed tip is usually tucked up behind the caudal edge of the soft palate when breathing
What swallowing, what does the epiglottis do?
covers the opening of larynx
-like a trap door
-directs ingests to esophagus
What are the vocal cords attached to?
the 2 arytenoid cartilages
How does the vocal cord tension get adjusted?
muscles move the cartilage
What forms the boundaries of the glottis?
Arytenoid cartilages and the vocal cords
What is the glottis?
opening to the larynx
Nonruminant animals have a second set of connective tissue bands, which are called?
false vocal cords or vestibular folds
These “false vocal cords” are/ are not involved in voice production.
are not
What are lateral ventricles?
blind pouches that are on each side of the larynx
Where are these lateral ventricles located?
project laterally into the space between the vocal cords and the vestibular folds
What are lateral ventricles involved with?
treatment of roaring in horses
-laryngeal paralysis
What is the trachea?
short, wide tube that extends from the larynx down through the cervical region to the thorax
Once in thorax, what happens?
The trachea divides into 2 main bronchi that enter the lungs
What is the division called?
the bifurcation of the trachea
-occurs at level of heart
What is the trachea held open by?
incomplete rings of hyaline cartilage spaced along the length of the trachea
What do these rings help prevent?
collapse when air is inhaled
When air inhaled, what happens?
a C shape with the open part of the C pointed dorsally
Lining of the trachea is similar to?
the nasal passages
-helps trap debris and project is toward the larynx
What is the bronchial tree?
passageways that lead from the bronchi to the alveoli
-divides into smaller and smaller passages like the branches of a tree
After it enters the lungs, ________________
each main bronchus divides into smaller bronchi, then divide into smaller bronchi and finally divide into tiny bronchioles, then to microscopic alveolar ducts
Alveolar ducts end in what?
groups of alveoli arranged like bunches of grapes
-called alveolar sacs
Diameter of these tubes (alveolar ducts) are ________
not static
They _____________
distal and constrict
-smooth muscle fibers in walls
ANS causes these tubes to dilate in intense activity, why?
when dilated, able to take in more air
ANS causes tubes to constrict when at rest, why?
irritants can cause severe branchoconstriction
What happens in alveoli?
external respiration takes place here
-O2 and CO2 are exchanged between blood and air
Structure of alveoli
tiny, thin walled sacs that are surrounded by networks of capillaries around an individual alveolus
What are alveolar walls and surrounding capillaries composed of?
simple squamous epithelium
This is the only boundary between the blood and air, why?
allows O2 and CO2 to diffuse back and fourth freely
What isn each alveolus lined with?
a thin layer of fluid that contains surfactant
What does surfactant do?
helps reduce surface tension of fluid
prevents the alveoli from collapsing as air moves in and out during respiration
Thorax bounded dorsally by
thoracic vertebrae
thorax bounded laterally by
ribs and intercostal muscles
thorax bounded caudally by
diaphragm
thorax bounded ventrally by
the sternum
What does the thorax (thoracic cavity) contain?
Lungs, heart, large blood vessels, nerves, trachea, esophagus, lymphatic vessels, and lymph nodes
What covers organs?
pleura
Which layer of the pleura touches the organ directly?
visceral layer
Which layer of the pleura lines the cavity?
parietal layer
What is the mediastinum?
portion of the thorax between the lungs
What does the mediastinum contain?
contains the heart and everything else, except the lungs
What is the diaphragm?
a thin, muscular sheet of skeletal muscles that are important for respiration
When the diaphragm is relaxed, what happens?
-it’s dome shaped with a convex surface facing in a cranial direction
The lung bases lie on the _________ portion of the diaphragm
cranial
The liver and stomach lie on the ___________ portion of the diaphragm
caudal
When the diaphragm is contracting, what happens?
dome shape somewhat flattens
-this action allows fro the volume of the thorax to enlarge
this makes respiration possible
2 lungs together form a __________ shape
cone
What surfaces do lungs have?
base, apex and convex, lateral surface
The base of each lung is in the _____________
caudal part of the thoracic cavity and lies on the cranial portion of the diaphragm
What are the lungs divided into?
lobes
What are the 2 ways to distinguish the lobes?
externally- visible groves and clefts (easiest to see)
internal- major branches of bronchi
Lobes in the left lung of dogs, cats, cows:
cranial lobe, middle lobe, caudal lobe
Lobes in the right lung of dogs, cats, cows:
cranial lobe, middle lobe, caudal lobe, accessory lobe
Lobes in left lung of horse:
cranial lobe and caudal lobe
Lobes in right lung of horse:
cranial lobe, caudal lobe, and accessory lobe
What is the hilus?
a small, well-defined area on the medial aspect of each lung
Why is the hilus important?
where air, blood, lymph, and nerves enter and leave the lung
The hilus is the only area where the lung is ___________
“fastened in place”
What happens at the capillary bed level in the pulmonary system?
gas exchange
Blood vessels that supply the lungs follow the _________
bronchi
What do the lungs need to do to meet the body’s demands?
effective movement of air into and out of the lungs at an appropriate rate and in enough volume
As new air is breathed in, what happens?
O2 has to be moved to the blood stream and CO2 is extracted
Old air has to be __________
blown out
What is intrathoracic pressure?
the pressure within the thorax
-is negative compared to the atmospheric pressure
What exists within the thorax?
A partial vacuum
What does this vacuum do?
pulls lungs tightly against the thoracic wall making them conform to the shape of the thorax
Pleural fluid provides lubrication between what?
lungs and thoracic wall
As the walls move, ___________
so do the lungs
-follow passively
What is inspiration?
the expansion of lungs and pulling air in
What is expiration?
the constricting of lungs and blowing air out
What does the negative pressure in the heart help with?
pulling blood into the large veins in the mediastinum
How does air get drawn into the lungs?
muscles work on the lungs making them expand and air is pulled in
Main muscles that help with inspiration:
diaphragm and external intercostal muscles
When those muscles contract, what happens?
the ribs rotate upward and forward
What does this rotation of the the ribs do?
increases the size of the thoracic cavity
Muscles work on the lungs in the _____________ of inspiration
opposite manner
Main muscles that help with expiration:
abdominal muscles and internal intercostal muscles
When these muscles contract, what happens?
push abdominal organs into the diaphragm and intercostal m,uncles then rotate the ribs back into their original position——-> decreasing size of thoracic cavity
What is tidal volume?
the volume of air inspired and expired during one breath
-this varies according to the body’s needs
When animal is at rest= (tidal volume)
smaller
when animal is excited or active= (tidal volume)`
larger
What is minute volume?
the volume of air inspired and expired during 1 minute
How is minute volume calculated?
multiply tidal volume by # of breaths per minute
What is residual volume?
volume of air remaining in the lungs after maximum expiration
What is the basic force behind exchange?
simple diffusion
What is diffusion?
high area of concentration to a lower area of concentration
What does atmospheric air contain?
high level of O2 and very little CO2
What is all of inspiration and expiratory muscle type?
skeletal muscle (all under conscious effort)
Breathing does/does not require conscious effort.
does not
What is the respiratory center?
an area in the brain stem where breathing is controlled
There are ______________ for the respiratory functions
individual controls
What do the centers send out?
nerve impulses on a subcutaneous level
-tells muscles when and how much to contract
Centers can be overridden by what?
voluntary control
What are the 2 systems of control?
mechanical and chemical control
What is mechanical control?
operates through stretch receptors in the lungs that sets limits on routine, resting, inspiration, and expiration
When the lungs inflate to a certain point, what happens?
nerve signal is sent to the resp. center saying lungs are full
Then what does the center do?
sends signal to muscles of inspiration telling them to stop and signal is sent to the muscles of expiration telling them to contract
When the lungs deflate to a certain point, what happens?
whole system starts again in reverse order
What does chemical control monitor?
blood and only intervene when something is out of balance
Where are chemical receptors located?
in brain stem and blood vessels (carotid artery and aorta)
What do the receptors monitor in arterial blood closely?
oxygen content, CO2 content, and pH
