HSF week 7

• true ribs are attached directly to the sternum (1-7)
• falsa ribs are attached via costal cartilage of rib 7 (8-10) 
• floating ribs are attached only to the vertebrae (11 + 12)

• typical ribs are ribs 3-9. they are continuous with the costal cartilage (anteriorly), they are smooth and flat bones that curve around the thorax, the head articulates with 2 thoracic vertebrae, they have an articular surface on their tubercle for the transverse costal facet of the same numbered vertebrae
• 1st rib is atypical as it only articulates with T1, has grooves and ridges on its surface and is a weird flat shape
• Rib 2 because it is also flat like rib 1 
• 10 only articulates with T10 
• Ribs 11 and 12 only articulate with vertebrae, do not connect to the costal cartilage, do not curve, and have no tubercle

manubrium, body and xiphoid process

the sternebrae

the 7th

• A - articular site for clavicle
• B - articular site for rib 1 
• C - articular demifacets for rib 2
• D - articular facets for ribs 3-6
• E - articular facets for rib 7 
• F - jugular notch 
• G - manubrium
• H - sternal angle (or manubriosternal joint)
• I - body of sternum
• J - xiphoid process

• A - spinous process
• B - vertebral foramen
• C - costal facet of transverse process (for tubercle of rib)
• D - superior costal facet
• E - vertebral body 
• F - superior articular process (and facet)
• G - transverse process
• H - superior articular process (and facet)
• I - transverse process
• J - transverse costal facet 
• K - spinous process
• L - superior costal facet 
• M - inferior vertebral notch
• N - inferior costal facet

between head of rib and costal facets on the body of the vertebrae. Inferior facet on the rib articulates with the superior facet of the same numbered rib. it is a synovial plane joint with 2 compartments (contained within one fibrous joint capsule)

the radiate ligament of the head of the rib

between the rib and the transverse process. a plane synovial joint.

superior costotransverse ligament, lateral costotransverse ligament, costotransverse ligament

• A - superior costotransverse ligament 
• B - costovertebral joint 
• C - costotransverse joint 
• D - costotransverse ligament 
• E - lateral costotransverse ligament

between the rib and the costal cartilage. hyaline cartilaginous joint (primary cartilagenous, synchondrosis)

between costal cartilage and the sternum . rib 1 is a synchondrosis (primary cartilaginous, made of hyaline cartilage). 2-7 are synovial plane joints.

the radiate sternocostal ligaments

between the costal cartilage of the false ribs. synovial plane joints (with very limited movement)

the manubriosternal joint/sternal angle. located at T4/5. symphyses (so secondary cartilaginous)

between the xiphoid process and the body of the sternum. secondary cartilaginous (symphyses)

the superior thoracic inlet/apeture

T2/3

the inferior thoracic aperture/outlet

• IVC - T8 
• Oesophagus - T10 
• aorta - T12

the vagus and phrenic nerve

right - liver sits just under it

the left and right crus

attaches to rib 12 be the lateral arcuate ligament and the transverse process of L1 by the medial arcuate ligament. the left and right rus to the vertebral bodies.

right crus is larger. right runs from L1-L3/4, left crus runs from L1 to L2/3

the caval opening for IVC< oesophageal haitus and aortic haitus

cervical plexus

• external intercostals - fibres run anteroinferiorly (hands in front pockets). more prominant laterally, not really seen medially
• internal intercostals - fibres run posteroinferiorly (hands in back pockets). more prominent medially 
• innermost intercostals - run same direction as internal intercostals

thoracic aorta and internal thoracic artery. thoracic aorta gives rise to posterior intercostal arteries. internal thoracic artery arises from the subclavian artery, supplies the anterior aspect of the thoracic wall and gives rise to the anterior intercostal arteries. anterior and posterior intercostal arteries often anastomose

pretty much follows arterial supply. anterior intercostal veins empty into the internal thoracic vein which empties into the brachiocephalic vein. posterior intercostal veins empty into the azygous veinous system (hemi and accessory hemiazygous veins drain into azygous which drains into SVC

intercostal muscles are supplied by intercostal nerves (arising from T1-T11). Motor nerves from T1 innervate the first intercostal space

VAN - veins most superior then artery then nerve

• principle - external intercostals, internal intercostals, diaphragm 
• accessory - sternocleidomastoid and the anterior, middle and posterior scalenes

normal expiration is due to passive recoil of the thorax. active breathing is due to internal costals (other than the interchondral part), rectus abdominus, external and internal obliques and the transversus abdominus (they contract, reducing volume of the abdomen, which in turn places pressure on the diaphragm and the thorax)

• A - central tendon of diaphragm 
• B - lateral arcuate ligament 
• C - medial arcuate ligament
• D - left crus
• E - right crus

• A - subclavian artery 
• B - posterior intercostal artery
• C - Aorta
• D - internal thoracic artery 
• E - anterior intercostal artery

• A - right brachiocephalic vein
• B - posterior intercostal vein
• C - posterior intercostal vein 
• D - azygous vein 
• E - anterior intercostal vein
• F - left brachiocephalic vein 
• G - accessory hemiazygous vein 
• H - internal thoracic vein 
• I - hemiazygous vein

helps warm up air, bringing it closer to body temperature and humidifying it

• olfactory and respiratory areas
• olfactory area is approximately the top third and contains projections from the olfactory nerve
• the respiratory area contains ciliated cells

• turbinates, called the superior, middle and inferior concha 
• creates turbulence in the nasal cavity so that air remains in contact with the vascularised nasal walls

• A - superior concha
• B - middle concha
• C - inferior concha 
• D - vestibule

the meatus or meati

frontal, ethmoid, splenoid and maxillary

frontal, ethimoid and sphenoid

the middle meatus

• A - ethmoid sinus
• B - frontal sinus 
• C - sphenoid sinus
• D - maxillary sinus

lips anteriorly, hard and soft pallets superiorly, tongue inferiorly

the mylohyloid muscle - acts like a diaphragm

the sulcus terminalis (the v shaped groove)

immune/lymphoid tissue. located posterior to the sulcus terminalis

• vallate papillae - anteriorly line the sulcus terminalis 
• foliate papillae - kind of grooves on the lateral tongue 
• fungiform papillae - larger mushroomish looking bumps. taste buds are embedded within the sides of these
• filiform papillae - smaller hair like papillae that cover a lot of the tongue

• A - lingual tonsil 
• B - palatine tonsil
• C - sulcus terminalis 
• D - valate papillae
• E - foliate papillae 
• F - fungiform papillae

• extrinsic - alter position 
• intrinsic - alter shape

incisors (2), canines (1), premolars (2), molars (3) (the third molars are the wisdom teeth)

the cartilage that sits on top of the trachea, forms a complete ring around the larynx

where the 2 lamina of the thyroid meet in the middle

• A - epiglottis 
• B - hyoid bone
• C - thyroid cartilage
• D - cricoid cartilage
• E - laryngeal inlet 
• F - oesophagus 
• G - trachea

they attach to the arytenoid cartilage, which sits on the posterolateral aspect of the cricoid cartilage, posteriorly, and project anteriorly to the angle of the thyroid

the intrinsic muscles of the larynx

nasopharynx, oropharynx and laryngopharynx

the main muscles of the pharynx. superior, middle and inferior constrictor muscles. when they constric they close the pharynx.

• A - maxilla 
• B - palatine bone
• C - soft palate 
• D - uvula 
• E - tongue
• F - mylohyoid muscle 
• G - mandible

also known as adenoids. located at the roof of the pharynx, where the nasal cavity joints it

located in the nasopharnyx. equilibrates pressure between the middle ear and the atmosphere and therefore can cause problems if blocked (such as by mucus). the salpingopharyngeays muscles can contract to pull in the opening of this tube.

• A - opening of auditory tube
• B - pharyngeal tonsils (adenoids) 
• C - uvula 
• D - auditory tube 
• E - salpingopharyngeus muscles

superiorly is the soft palate and uvula, inferiorly is the posterior third of the tongue, anteiroly is the end of the dental arches (after the last tooth)

• A - lingual tonsils 
• B - epiglottis 
• C - palatine tonsils

posterior to the larynx

• A - epiglottis 
• B - laryngeal inlet
• C - oesophagus
• D - trachea

16

• the conducting zone and the respiratory zone 
• becomes the respiratory zone where we begin to see alveoli

• type 1 (squamous pulmonary epithelial cells), type 2 (septal) and macrophages
• septal cells produce surfactant, macrophages are immune surveillance

the amount of air moved with each breath (around 500mL)

the conducting zone where no gas exchange occurs

3000 mL

around 70 mL

12

around 4200 mL/min

around 4200 mL/min

• phrenic nerve innervates contraction of the diaphragm, reducing thoracic pressure 
• the superior laryngeal nerve causes abduction of the air way (further decreasing pressure). the hypoglossal nerve causes the tongue to contract, moving it out of the way

• post inspiration/early expiration
•  - phrenic nerve activity stops so diaphragm relaxes 
•  - adduction of upper airway muscles (increases resistance to airflow out of the lung 
• and 
• second phase (more passive expiration)
• - no contracting muscles 
• - alveolar pressure equilibrates with the atmosphere

it falls (there is so much cross sectional area that constriction doesn't change volume or therefore resistance)

parasympathetic

smaller lungs have more resistance (so babies have higher airway resistance)

• fibrosis, increased surface tension, alveolar oedema, aging and emphysema (collection of pollutants in the lung) 
• things that reduce the radius of the alveoli increase the pressure within them and therefore reduce airflow into the lung (as lower pressure in the lung draws more air in)

they have limited surfactant production, increased airway resistance and weak muscles that struggle to overcome this

• the volume of air that can be expired after a normal breath (around 700-1200 mL)
• due to forced expiration

the volume of air that can be inhaled after a normal breath (around 1900-3100mL) (does not include tidal volume)

the total amount that you can be inspire from the end of a normal expiration (includes tidal volume - so tidal volume + inspiratory reserve volume) (between 3600mL and 2400 mL)

the total amount of air that you could inspire (from maximal expiration to maximal inspiration) (inspiratory capacity + expiratory reserve volume) (between 4800mL and 3100 mL)

the amount of air that cannot be expired from the lung (due to anatomical dead space - the trachea etc cant just collapse) (between 1200 and 1100 mL)

from the end of a normal expiration to the very bottom of the spirogram (so residual volume + expiratory reserve volume)

• residual volume + expiratory reserve volume + tidal volume + inspiratory reserve volume 
• usually between 6000 and 4200 mL

• A - inspiratory reserve volume
• B - tidal volume
• C - expiratory reserve volume
• D - residual volume
• E - inspiratory capacity
• F - functional residual capacity
• G - vital capacity
• H - total lung capacity

the forced expiratory volume of 1 second. taken at the very end of max. inspiration

forced vital capacity - total volume that is expired with forced expiration

• we see a greatly reduced FEV1 
• slight reductions in FVC and vital capacity 
• and an increase in residual volume 
• - doesnt really change total lung capacity, they just cant really get all of the air out of their lungs in a single breath

• Lower inspiratory reserve volume and FVC 
• - therefore decreased vital capacity 
• - residual volume should stay the same

• minute ventilation - total volume of air moved in and out of the lungs in one minute 
• = respiratory frequency (fR) x tidal volume (Vt)

amount of air moved in and out of the alveoli/respiratory zone in one minute 

•  V(dot)A = alveolar volume (VA)  x respiratory rate (fR) 
• alveolar volume (VA) = titdal volume (VT) - dead space (VD)

• VRG (ventral respiratory group) - source of respiratory rhythm (we call it the respiratory pacemaker)
• DRG (dorsal respiratory group) - integrating centre for peripheral afferents (sensory information). communicates with the VRG 
• PRG (pontine respiratory group) - integrates the respiratory phases and integrates some peripheral afferents

low PaO2 (arterial PO2), high PaCO2 and low pH

chemoreceptors (peripheral and central)

peripheral are located mainly where the common carotid artery bifurcates into internal and external carotid arteries (carotid body) and on the aortic arch (aortic bodies)

the glossopharyngeal nerve

the vagus nerve

a blood vessel surrounded by type 1/glomus cells (which are the chemoreceptors). when stimulated the glomus cells release neurotransmitters which activate afferent terminals of the glossopharyngeal nerve.

travel via the glosspharyngeal or vagus nerves and synapse into the NTS (a specialised region within the DRG), which will go on to synpase with neurons of the VRG. The VRG will stimulate increased respiratory muscle motor output, increasing ventilation

the surface of the brainstem, close to the VRG group. While the BBB typically repels ionic substances (including H+ and HCO3-), CO2 is not ionic and can cross. Within the CSF it will dissolve into H+ and bicarbonate, and these H+ ions will stimulate the central chemoreceptors. this is a slower response than that by peripheral chemoreceptors (more important for establishing a baseline, rather than responding to immediate conditions). activation of central chemoreceptors will cause them to directly stimulate VRG.

partial pressure of the gas x the solubility of the gas

0.003mL/(dL.mmHg)

area, diffusion constant (solubility/sqrt(molecular weight)), pressure, membrane thickness

have a large volume (area), are thin

ventilation-perfusion matching - the amount of blood supplied to the lungs compared to the volume of air (should be roughly the same)

shorter vessels (as located close to the heart), which have large cross sectional area

• decrease in ventilation means that VA < Q and therefore VA/Q<1
• this will result in the vasoconstriction of pre-capillary units, diverting blood from poorly ventilated regions to better ventilated alveoli

CO2 is more soluble

lower pH shifts haemoglobin binding curve to the right - more likely to donate O2 at higher PO2

shifts the curve to the right - makes Hb more likely to release O2 at higher pO2

• an increase in RBC production and therefore abnormally high Hb concentrations 
• - people with this will have higher blood O2 conc.

dissolved CO2 (forming carbonic acid), carbamino compounds (CO2 reacts with the amino group of haemoglobin forming carbamino Hb (carbamino Hb also reduces its affintiy to Hb), and bicarbonate

carbonic anhydrase

as pCO2 increases, this pushed the formation of HCO3- within the RBC forward. as HCO3- increases it is pushed out of the cell. this is done using a chloride-bicarbonate exchanger (as HCO3- doesnt readily cross the pm). this is done to maintain electroneutrality of the RBC. this means that less chloride is in veinous blood as it is actually within the RBCs

as H+ increases, affinity of Hb to O2 will decrease

as O2 conc. decreases, Hb affintiy for CO2 actually increases - helps with CO2 loading

10-12 cm

stretches and moves inferiorly during inspiration and recoils during expiration

prevents it from collapsing despite pressure changes during breathing

right is wider and more vertical than the left. right bifurcates sooner.

from the trachea to the 2 main bronchi, which will seperate into the secondary or lobar bronchi (2 for the left, 3 for the right), which will further divide into the tertiary or segmental bronchi (10 for each lung). anything more than tertiary bronchi becomes a bronchiole. C shaped rings of cartilage are gradually replaced by smooth muscle.

parietal and visceral pleura

reach above rib 1 and attach to the root of the neck. they extend to just above the inferior thoracic outlet (so just above the diaphragm) and medially they form the walls of the mediastinum

they are spaces within the pleural cavity that the lungs dont fill. costomedial recess is located between the ribs and the midline. costodiaphragmatic is between the costal and diaphragmatic pleura

on the diaphragm

• left - oblique separates superior from inferior
• right - horizontal separates superior from middle, oblique separates middle from inferior

• A - horizontal fissure
• B - oblique fissure
• C - lingula
• D - cardiac notch 
• E - oblique fissure

the root is the structures that connect the lung with the mediastinum (pulmonary veins and arteries, and bronchus), the hilum is a depressed region on the mediastinal side of the lungs where these structures enter

the right bifurcates sooner than the left, and is larger. the pulmonary artery would have bifuricated in the right while it hasn't yet in the left.

bronchus is located posteriorly, pulmonary arteries more superiorly, pulmonary veins more inferiorly

the lingual

the inferior lobe

the superior lobe

the terminal bronchioles, which give rise to the respiratory bronchioles

each lung has a pulmonary artery, which divided into secodnary lobar arteries and then teriary segmental ateries

the bronchial arteries, stemming from the descending aorta

bronchial veins drain into the azygous, and accessory hemiazygous veins