Respiratory Anatomy Flashcards
1
Q
What are the functions of the respiratory system?
A
- perform gas exchange: get O2 in blood and CO2 in atmosphere
- regulate blood pH; CO2 levels directly affect pH of blood in interstitial fluids because CO2 can combine with water to form carbonic acid (CO2 directly correlates with H+)
- provide for olfaction (smell); gets you away from bad smelling things which might be dangerous
- provide for phonation (sound); draw air across vocal chords and make sounds
2
Q
What is the framework of the thorax?
A
- 12 thoracic vertebrae
- 12 pairs of ribs and costal cartilages (gives rib cage flexibility)
- sternum (manubrium, body, xiphoid)
- first 7 ribs come and touch the sternum; true ribs
- 3 more false ribs; they attach to the sternum indirectly by touching the cartilage of the ribs above them
- 2 floating ribs; they don’t come to the front, attached to muscles of the back
- tips of the ribs are cartilage giving some elasticity
- suprasternal notch- can feel trachea just above it
- sternal angle- where body of sternum meets manubrium at 2nd intercostal space, right behind is aortic arch and bifurcation of trachea, good for palpating heart sounds
3
Q
What type of joint exists between the posterior ribs and thoracic vertebrae?
A
- synovial joints
- can dislocate it
4
Q
A
- costal angle is where bone is weakest so impact will usually break thoracic cage here
- costal groove: contains an intercostal VAN (vein, artery, nerve)
5
Q
During quiet breathing, what muscles are you recruiting?
A
- diaphragm: moves down and stomach moves out
- external intercostals: pull ribs up and out
- anteroposterior and superior inferior dimensions of thorax change
6
Q
How do you exhale in quiet breathing?
A
- just relax the muscles you used to inhale
- rely on the fact that you stretched out your lungs and there is a lot of elastic tissue
7
Q
What are the accessory muscles of breathing and what do they do?
A
- sternocleidomastoid
- scalenes (1st and 2nd rib to get increased anteroposteral dimension of thorax)
- pull up on rib cage
- external intercostals working with them
8
Q
What muscles are engaged to exhale quickly (not quiet breathing)?
A
- internal intercostals
- pull rib cage down
- compress thorax and abdomen, elevate diaphragm
- rectus abdominis, external and internal obliques all engaged to pull the ribs down and pushing your viscera against your diaphragm
- transversus abdominis
- force viscera in abdomen up to get air out of lungs
9
Q
What are the muscles of breathing?
A
10
Q
Describe the layers of the intercostals
A
-dashed line is where it is starting to turn into a tendon
11
Q
Describe the layers from the lungs outwards of the intercostal VAN
A
- visceral pleura
- parietal pleura
- pleural space between the above 2: can get effusion in here, blood in here, or air in here then lungs can’t move
- innermost intercostals
- internal intercostals (useful for expiration)
- rib with intercostal groove in inferior border
- vein, artery nerve, slide in behind intercostal groove
- VAN serves the muscle and the nerves innervate the skin lying over the ribs
- nerves are spinal nerves from each level of the thorax (somatic motor neurons- these are voluntary skeletal muscles)
- external intercostals
12
Q
What is the safest place to go in to aspirate?
A
-top of rib to avoid VAN
13
Q
What is the blood supply to the thoracic cage?
A
- forms anastomosis
- internal thoracic arteries around sternum from subclavian artery
- internal thoracic arteries give rise to intercostal arteries at the front which anastomose with intercostal arteries that arise from back of the thoracic cage which arise from the descending thoracic aorta
14
Q
What is the venous drainage from the thoracic cage?
A
- internal thoracic veins come from brachiocephalic vein
- at the back, it drains into hemiazygous vein and azygous vein on the right
- both of these drain into superior vena cava
***listen to this year’s podcast about this again
15
Q
What is the diaphragm?
A
- ring of skeletal muscle with aponeurosis in the middle
- innervated by the phrenic nerve
- shaped like a dome
- when it contracts, it pulls dome down to increase volume of lungs
- attaches on inferior border of thoracic cage on free floating ribs
- at the front it attaches on costal cartilages
- supplied by the phrenic nerve
- separates pleural cavity from peritoneal cavity
17
Q
What structures pass through the diaphragm?
A
- aorta: passes through left and right legs of diaphragm, thoracic duct travels with it (brings back liquid to circulation to subclavian vein)
- esophagus: vagus nerve travels with it
- inferior vena cava
- pass through hiatus if in muscle
- caval opening if it is through aponeurosis: inferior vena cava passes through here (maintains patency of IVC because it is collagen/connective tissue so doesn’t change shape)
19
Q
Where does air travel through in upper respiratory tract?
A
- nose
- nasal cavity behind it which has conchae to make the air get turbulent so any particulate matter gets trapped in mucus lining
- nasal cavity covered by a mucous membrane which filters, warms, and humidifies the air protecting the lower respiratory system
- pseudostratified ciliated columnar epithelium
- 4 sinuses: sphenoid sinus, frontal sinus, ethmoid sinus between eyes, maxillary sinus which communicate with nasal cavity and has mucus membrane
- air then passes into pharynx
- lot of ciliated epithelium at back of nasal cavity which is moving particulate matter to the back of the throat for you to spit or swallow
22
Q
What is the trachea? What are characteristics of it?
A
- tube that conducts air down to region of lung to do gas exchange
- C shaped rings of cartilage maintain patency
- at the back, there is tracheal smooth muscle that is controlled by ANS
- most people that are healthy this muscle is relaxed and open, only in individuals that are genetically predisposed to allergies, etc. that will get bronchospasms sometimes
- trachea bifurcates into primary bronchii
- at bifurcation there is ring of tissue (carina) that sticks into trachea covered by irritant receptors (if something makes it all the way down there it will cause you to cough)
- lined by pseudostratified ciliated columnar epithelium to move things up and out towards larynx to get rid of it (mucociliary apparatus); only works if there are mucus glands making mucus to trap those things
23
Q
What are the primary and secondary bronchii?
A
- primary bronchii enter each lung at the hilus then divide into secondary bronchii
- right primary: shorter, more vertical
- left primary: longer, more angled (supported by rings of cartilage) because it has to pass around to heart
- secondary (lobar) bronchi for each lobe (3 in right, 2 in left because heart takes up room) supported by plates of cartilage
25
Q
A
- lingula: small tongue like projection on left lung
- cardiac notch to accomodate heart
26
Q
What are the tertiary bronchi? What do they supply?
A
- secondary bronchi divide to create tertiary (segmental) bronchi
- 10 tertiary bronchi in right lung, 8 in left lung
- area supplied by tertiary bronchi is the bronchopulmonary segment
- functionally and anatomically independent: if you have lung cancer in one of those lobes, you can cut it out and be fine because it has its own elastic tissue, arteriole, venous, and nervous supply (lung reduction surgery)
- cartilage rings replaced by cartilage plates
27
Q
What are bronchioles?
A
- eventually cartilage is replaced by smooth muscle
- conducting zone ends at terminal bronchiole
- smooth muscle bands regulated by ANS
- bronchioles branch up to 14x to make terminal bronchioles
- see most resistance here so it makes it difficult to breathe (problem in asthma)
28
Q
What is a lobule?
A
- also called acinus
- each terminal bronchiole forms a lobule which contains: terminal bronchiole, arteriole, venule, lymphatic vessel, all wrapped in elastic tissue
- terminal bronchioles divide into respiratory bronchioles which are thin enough to do gas exchange
- respiratory bronchioles are connected to alveolar sacs by alveolar ducts which are clusters of alveoli (SA is increased with alveoli in clusters)
- pulmonary artery travels down to the acinus region and is forming capillary beds to do gas exchange
- emphysema elastic tissue between alveoli breaks down
29
Q
What is bronchial artery supplying?
A
- conducting areas have thick walls so they can’t do gas exchange
- they need oxygen rich blood from systemic circulation which feeds trachea, bronchioles, etc. until you get down to gas exchange regions
30
Q
What does the pulmonary artery supply?
A
- follows airways until acinus region then makes capillary beds around alveol
- blood taken away by pulmonary veins to left atrium
31
Q
What are functions of the airways?
A
- structural support to maintain patency
- air conditioning to moisten and trap pathogens
- protection all throughout because you have macrophages in alveoli engulfing things
**listen again
32
Q
What are the 2 types of alveolar cells?
A
- Type 1: primary site of gas exchange, thin squamous cell (pneumocyte), forming part of gas exchange membrane, want as little tissue here
- Type 2: creates surfactant that helps to break up watery film on alveoli to make it easier to expand and take a breath (reduces surface tension of alveolar fluid), less muscular effort needed to breathe in
- bubble bursts in inward direction because water molecules want to collapse which is why we need surfactant
- elastic fibres help to keep alveoli open
36
Q
Describe the gas exchange membrane
A
Consists of:
- type 1 pneumocyte
- basement membrane
- pulmonary capillary endothelial call
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