2 Flashcards
Which IC space does the superior border of the heart lie on?
2nd IC space
Why is the angle of Louis an important landmark?
Marks the level of the intervertebral discs which lie between T4 and T5.
Manubriosternal junction.
Is where the superior border of the R atrium lies.
Marks the bifurcation of the trachea.
Which cardiac chamber forms most of the inferior border of the heart?
R ventricle
Moving away from the heart, what’s the 3rd branch of the aorta?
3rd – L. common carotid
What class are adrenaline and noradrenaline (catecholamines)?
Alpha-adrenoceptor agonist
Which structures does the ligamentum arteriosum attach to?
Pulmonary arteries and aorta
What is the ligamentum arteriosum?
A remnant of the foetal ductus arteriosus that allowed passage of blood from the high-pressure pulmonary arteries to the aorta
When does the ductus arteriosus close?
On day 1-2 of life in response to hyperoxia, it undergoes fibrosis to form the ligamentum arteriosum that inserts into the aortic arch opposite the left subclavian artery.
What is the function of alpha-adrenoceptor agonists?
Induces smooth muscle and blood vessel contraction
Which embryonic structure, is the brain derived from?
Neural tube
Isoprenaline use + class
Use: Treatment of bradycardia, heart block, rarely for asthma.
Class: Non-selective beta-adrenergic receptor agonist
Differentiate between: endocardium, myocardium, epicardium, pericardium
Endocardium – lines inside of heart
Myocardium – muscular tissue of the heart
Epicardium – visceral lining of the outside of heart
Pericardium – lines the cavity (one with epicardium)
What endothelial ion change causes release of nitric oxide?
A rise in intracellular calcium.
NO then diffuses into vascular smooth muscle cells and causes hyperpolarisation with a fall in intracellular Ca2+ in myocytes.
Result: vasodilatation
Describe NO synthesis + how it affects blood vessels
Vascular endothelial cells produce NO from endothelial nitric oxide synthase (eNOS) in response to raised shear stress from blood flow.
eNOS is activated by a rise in intracellular calcium.
NO then diffuses into vascular smooth muscle cells and causes hyperpolarisation with a fall in intracellular Ca2+ in myocytes.
Result: vasodilatation
How is a rise in blood pressure signalled to the CNS?
Increased firing in CN IX afferents from carotid sinus
In an ECG what does the P, Q, R, S + T represent?
P – Arterial depolarisation (systole)
QRS – Ventricular depolarisation (systole)
T – Ventricular repolarisation (diastole)
What is the anterior interventricular artery a branch of?
L coronary artery
Which arteries arise directly from the ascending thoracic aorta?
Coronary, brachiocephalic, L. common carotid, L subclavian
What are chronotropic, and inotropic agents?
Chronotropic - Change the heart rate.
Inotropic - Modifying the force contraction of muscles.
Give examples of positive + negative inotropic agents.
+ve = digoxin, insulin, catecholamines (A, NA)
-ve = beta-blockers, some calcium channel blockers
What does the P-R interval, S-T segment + Q-T interval on an ECG indicate?
P-R interval – Delay at AVN
S-T segment – interval between ventricular depolarisation + repolarisation
Q-T interval – Total time for ventricular depolarisation to repolarisation (prolongation or shortening increases risk of arrhythmias). It’s inversely proportional to HR.
What class of drug is calcium-channel blockers + what effects does it have?
Negative chronotropic
- Reduces HR
- Vasodilation
Negative inotrope
- Reduce force of contraciton
- Reduce aldosterone production (blocking channels of adrenal cortex) —> decreases BP
What class of drug is digoxin + what affects does it have?
Digoxin is a = +ve inotrope, -ve chronotrope
Increases force of contraction, reduces HR.
What does ACh do to the HR?
Which receptors does it target?
Targets muscarinic (M2) cholinergic receptors and decreases HR.
MoA: inhibition of T-type Ca2+ channels + activation of K+ GIRK channel. K+ efflux
–> hyperpolarised
What causes the 1st heart sound?
atrioventricular valve closure (mitral + tricuspid)
What causes the 2nd heart sound?
semilunar valve closure (aortic + pulmonary)
What does a larger P wave on ECG indicate?
P – Enlargement of atrium
What does a larger Q wave on ECG indicate?
Q – MI
What does a larger R wave on ECG indicate?
R – Enlarged ventricles
What is dromotropy?
Conduction velocity of AVN
What is lusitropy?
Relaxation of myocardium
What does the ‘x’ in the JVP waveform indicate?
Atrial relaxation
What does the ‘a’, ‘c’, ‘v’ + ‘y’ in the JVP waveform indicate?
a – atrial contraction
c – tricuspid bulging
v – filling of atrium
y – emptying of atrium to ventricle
What is stroke volume?
Vol of blood ejected by a ventricle in a single contraction
SV = EDV – ESV
What is EF?
EF (%) = SV/EDV x100
What is isovolumetric contraction?
Isovolumetric contraction – ventricular volume unchanged, ventricles begin to contract, intraventricular pressure rises sharply.
What is isovolumetric relaxation?
Isovolumetric relaxation – ventricular pressure falls, volume of blood in chamber remains the same.
List the stages in the cardiac cycle + the state of the AV + semilunar valves at each point.
Atrial systole – AV=O, SL=C Isovolumetric contraction – AV=C, SL=C Ventricular ejection – AV=C, SL=O Isovolumetric relaxation – AV=C, SL=C Ventricular filling – AV=O, SL=C
Which nerves supply the mediastinal pleura (parietal + costal) lining of the chest wall + the pericardium?
Parietal – IC nerves + phrenic nerve
Costal – IC nerves
Which nerve is involved in swallowing?
When the swallow response is initiated, message is sent to the glossopharyngeal (CN IX), the vagus (CN X), and the hypoglossal nerves (CN XII).
The glossopharyngeal is considered the major nerve for the swallowing center.
A patient with a stab wound to the neck may be unable to maintain ventilation because of injury to which nerve?
Phrenic nerves
What is the cardiac plexus?
Plexus of nerves situated at the base of the heart
Formed by cardiac branches derived from both the sympathetic + parasympathetic nervous systems
What does the phrenic nerve supply?
Where does it originate from?
C3-C5
Innervates mediastinal pleura + diaphragm!!
What structure does the intercostal nerve supply?
Where does it arise form?
Arises from anterior rami of T1-T11
Supplies the intercostal muscles
What structure does the subcostal nerve supply?
Where does it arise from?
The anterior division of the twelfth thoracic nerve (subcostal nerve) is larger than the others; it runs along the lower border of the twelfth rib,
Innervates the transverse abdominis
What do juxta-glomerular cells synthesis + secrete?
Renin
What do chromaffin cells in adrenal medulla secrete?
Adrenaline, NA, little DA, enkephalin and few other hormones
What is the pattern in AF?
Irregularly irregular.
What is SERCA? What is its function?
Sacro-endoplasmic reticulum Ca2+ - ATPase.
Resides in Sacro-ER within myocytes.
Transfers Ca2+ from cytosol of cell to ER by ATP hydrolysis during muscle relaxation.
What structure secretes ADH (vasopressin)?
Posterior pituitary
What structure responds to low blood flow by activation of an endocrine cascade?
Juxtaglomerular kidney cells are stimulated to release renin by signally from the macula densa
Where does adrenaline act on in the heart?
B1-adrenoceptors via cAMP on:
SAN (increase rate), Atrial muscle (increase force), AVN (increase automaticity), Ventricular muscle (increase automaticity + force)
Where does the superficial part of the cardiac plexus lie?
Beneath aortic arch, anterior to R pulmonary A.
At what vertebral level do the renal arteries branch from the aorta?
L1
Where may the dorsalis pedis pulse be palpated?
Lateral to extensor hallucis longus tendon on the dorsal surface of the foot
How does the ultrastructure of a vessel change in atherosclerosis?
Tunica intima thicken;
Little change to the adventitia.
Tunica media thickens, with increased elastin + muscle - this adds to the raised resistance.
What is the role of the atrioventricular node?
Delay atrio-ventricular depolarisation
What ventricular ion movements are responsible for the Q-T segment seen on ECG?
Sodium + calcium influx, potassium efflux
What ion movement is responsible for the pre-potential of SAN + AVN?
Na+ influx (leak channels) – are continuously open to allow sodium influx that causes gradual depolarisation
How does parasympathetic stimulation alter ion movements in cardiac pacemaker cells?
Increased potassium efflux.
When ACh from vagus nerve acts on muscarinic receptors
Which ion acts on ventricular contraction?
Calcium
Sympathetic stimulation increases sodium + calcium permeability via B1-adrenoceptor activation
Increased CO2 causes the oxygen-dissociation curve to shift in which direction?
Right (Bohr shift). Hb gives up oxygen more readily.
What are the 2 contractile proteins that make up cardiac muscle?
Actin + Myosin
What does NA do to the heart + how in detail?
Binds to the beta-1-adrenergic receptor
Activates funny sodium channel and T-type calcium channel so sodium and calcium ions enter and depolarise SAN
Which complex is attached to tropomyosin?
Troponin
What makes up cardiac myocytes?
Myofibrils
What is one functional unit of the heart muscle called?
Sarcomere
Where does calcium ions bind on actin for muscle contraction?
TnC subunit of troponin TnI stops inhibiting myosin from binding to actin.
What does phospholamban activate when triggered?
Activates a pump on the sarcoplasmic reticulum (SR) which causes Ca2+ to be taken up by the SR.
Name the 3 subunits of troponin. What are their functions?
TnT – keeps whole complex bound to tropomyosin
TnC – binding site for Ca2+ –> triggers contraction
TnI – inhibits myosin binding to actin
Describe the structure of actin filaments.
Globular actin proteins forming 2 helical strands.
Between strands = rod shaped protein (tropomyosin) cover the binding sites.
Actin = thin filament.
What do myosin heads contain?
2 heads that contain myosin ATPase
What is the hinge + tail region of myosin made up of?
Heavy alpha helix chains
Which is the thin filament + which one is the thick?
Actin = thin, myosin = thick
Why is hydrolysis of ATP necessary to allow actin + myosin to interact forming a cross-bridge?
Hydrolysis of ATP energises the molecule, cocking it as myosin heads move along the thin filament.
ADP + Pi stays attached to thick filament.
Pi is released which cocks the myosin head from 90 degrees to 45 (power stroke)
How does depolarisation of cardiac muscle cells differ from that of other muscle cells?
Repolarisation takes much longer to occur thus cells cannot be stimulated at high frequency.
This prevents cardiac muscles going into tetanus.
Which rod shaped proteins cover the myosin binging sites on the actin filament?
Tropomyosin
Where does Ca2+ come from before they bind to TnC?
Sarcoplasmic reticulum + external environment
What does spirometry measure?
Ventilation (volumes of gases in + out of lungs)
What is dead space?
Anatomical – bits that don’t exchange gases e.g. conducting zone
Physiological – alveoli that are ventilated by not perfused by oxygen e.g. damaged walls of alveoli
Where does the venous sinus of the heart run along?
In the posterior AV groove
What is the role of 2,3-diphosphoglycerate?
2,3-DPG – by-product of anaerobic metabolism that increases oxygen delivery to tissues by reducing oxygens affinity with Hb.
Anaerobically respiring tissues produce more 2,3-DG so have greater delivery of oxygen from Hb.
What is the Bohr effect?
Right shift of oxygen dissociation curve
Why is the dissociation curve of HbF a different shape to that of HbA?
Gamma-chains cannot bind 2,3-DPG –> doesn’t reduce oxyhaemoglobin affinity –> Hb has higher affinity for O2.
What globin chains are present in HbF?
2 alpha + 2 gamma
What globin chains are present in HbA?
2 alpha + 2 beta
What is methaemoglobin?
It is a stable oxidized form of haemoglobin which is unable to release oxygen to the tissues, produced in some inherited abnormalities and by oxidizing drugs.
What does methaemoglobin reductase do?
Convert iron back to Fe2+ (the reduced state for oxygen to bind to haemoglobin)
What is carboxyhaemoglobin?
Hb with carbon monoxide bound
What is the shape of the myoglobin-oxygen dissociation curve?
Hyperbolic – because there is only one molecule to bind + after that it becomes fully saturated
What is the shape of the haemoglobin-oxygen dissociation curve?
Sigmoidal – because there are 4 oxygen molecules to bind at they show co-operative binding.
How do oxygen saturations change in anaemia?
No change in oxygen saturation.
Anaemia = a reduction in the conc. of haemoglobin per volume of blood. Oxygen carrying capacity reduced.
What is the name given to the process by which oxygen shifts the CO-Hb dissociation curve right?
Oxygenation of blood in the lungs displaces carbon dioxide from hemoglobin which increases the removal of carbon dioxide.
This property is the Haldane effect.
Conversely, oxygenated blood has a reduced affinity for carbon dioxide.
Thus, the Haldane effect describes hemoglobin’s ability to carry increased amounts of CO2 in the deoxygenated state as opposed to the oxygenated state.
What percentage composition of whole blood, is cells?
45%
What is the haematocrit?
Percentage of whole blood that is RBCs
What is the most prevalent plasma protein + what are its functions?
Albumin – synthesised in the liver
Exerting oncotic pressure to maintain of intravascular volume + binding of substances to aid in their transport.
What is blood serum?
Whole blood with all cells and clotting factors removed
How are platelets produced?
Budding off megakaryocytes.
What ratio of water to solutes are in blood plasma?
91:9
Define haemopoiesis.
Where does it occur + what is involved?
The formation of blood cells from haemopoietic stem cells in red bone marrow.
What does the common myeloid progenitor give off?
Megakaryocytes (thrombocyte)
Erythrocyte
Mast cell
Myeloblast (basophil, neutrophil, eosinophil, monocyte (macrophage))
What does the common lymphoid progenitor give off?
Lymphocyte (T lymphocyte, B lymphocyte (plasma cell))
Natural killer cell (aka granular lymphocyte)
Where does the R + L atrium receive blood from?
R – Superior + inferior vena cava + coronary sinus
L – 4 pulmonary veins (oxygenated blood)
Where + what is the fossa ovalis?
On the interatrial septum.
It’s an oval depression, the remnant of the foramen ovale, an opening in the interatrial septum of the foetal heart that normally closes soon after birth
What is the fibrous skeleton of the heart made up of?
Dense connective tissue surrounding + supporting heart valves
In embryonic folding, folding on the horizontal + median plane produces what?
Median – head fold + tail fold
Horizontal – 2 lateral folds
Overall curves embryo into a C shape.
What lies above the developing brain then moves down?
Cardiogenic mesoderm
What is the main force responsible for embryonic folding?
The different rates of growth of various parts of the embryo, especially the rapid longitudinal growth of the neural tube.
Where is the oropharyngeal membrane formed?
At the head end.
Where does the cloacal membrane form?
At the tail end.
What does the primitive gut differentiate into?
Anterior – foregut, Intermediate – midgut, Posterior – hindgut
What does the diaphragm develop from?
Septum transversum (central tendon), pleuroperitoneal membranes, dorsal mesentery of oesophagus, muscular components from somites at C3-5 levels.
What is the yolk sac a precursor to?
Umbilical cord
What does the parietal + visceral mesoderm cover?
Visceral – serous membranes covering organs.
Parietal – walls of peritoneal, pleural, pericardial cavities. They are continuous at the roots of each organ in their cavities.
Where is the septum transversum initially located?
Opposite cervical segments C3, C4, C5; muscle cells for diaphragm + phrenic nerve arises from these segments.
What cavities does the diaphragm separate?
The thoracic + abdominal cavities.
What does the specialised bit of mesophilia of gut allow?
Allows gut to move away from the body wall brining the blood vessels with it.
Pericardial + peritoneal cavities communicate via what?
Pericardioperitoneal canal – a tubular space.
What are invaginations of the ventral gut wall cranial to the septum transversum?
Lungs
The septum transversum is incomplete where?
Dorsally
At what day/week/month has all major elements of the lungs formed? + what hasn’t?
Day 64
Everything except the respiratory bronchioles, alveolar ducts + alveoli. Foetus can’t survive if born now.
Differentiate between type 1 + type 2 alveolar cells.
Type 1 – main site of gas exchange
Type 2 – surfactant-producing cells
What lies between the visceral + parietal pleura?
Pleural cavity (has small amount of lubricating fluid).
What is congenital diaphragmatic hernia + what does it cause?
When the pericardioperitoneal canal fails to close causing the gut to pop up into thoracic cavity –> lung stops developing properly.
What is ventilation + the 2 types of respiration?
Pulmonary ventilation – breathing
Pulmonary respiration – gaseous exchange between alveoli + blood in pulmonary capillaries.
> Physical process. Blood loses CO2 + gains O2.
Tissue respiration – gaseous exchange between blood in systemic capillaries + tissue cells.
>Metabolic process. Blood loses O2 + gains CO2.
When are the intercostal muscles used?
Internal – only used in exercise for expiration. Normally exhalation is a passive process.
External – inspiration
What is the main muscle of breathing?
The diaphragm – innervated by the phrenic nerve
What alters the size of the thorax?
The action of the breathing muscles (which contract due to nerve impulses from respiratory centre of the brain + relax in the absence of nerve impulses)
Which 2 collections of neurons are the medullary resp centre made of?
DRG – inspiratory movements + rhythm, quiet + forced breathing, when DRG inactive —> muscles relax
VRG – inspiratory + expiratory centre, forced breathing.
Name the accessory muscles of inhalation.
Sternocleidomastoid, scalenes, pectoralis minor
Name the accessory muscles of exhalation.
Internal intercostal, external oblique, internal oblique, transversus abdominis, rectus abdominis
Name the primary muscles of inhalation.
Diaphragm – phrenic nerves
Ext. intercostal muscles – intercostal nerves
What controls ventilation? Is it voluntary/involuntary?
ANS with limited voluntary override
Cerebral cortex has connections with resp centre
When pCO2 and H+ increases, what happens?
DRG neurons of medulla are strongly stimulated, impulses sent along phrenic + intercostal nerves to inspiratory muscles –> breathing resumes
Where are chemoreceptors of the cardiovascular system found?
Central – in/near medulla oblongata in CNS
• CO2, H+
Peripheral – aortic bodies, carotid bodies
• CO2, H+ (pH), O2
Which axons innervate aortic + carotid bodies?
Aortic – vagus nerves
Carotid – glossopharyngeal nerves
How is CO2 concentration and pH linked?
CO2 is lipid-soluble, it diffuses into cells + combines with water to form carbonic acid (H2CO3) which breaks down into H+ + HCO3-
More CO2 > more H+ > lower the pH > more acidic
What happens in respiratory failure?
CO2 accumulates so the chemoreceptor trigger zones get down regulated. As CO2 accumulates, body maintains more bicarbonates in kidneys to balance the acidosis.
When does peripheral chemoreceptors respond to changes in pO2?
When pO2 in arterial blood falls below 100mmHg but is still above 50mmHg
Name + explain the 2 types of respiratory failure.
Type 1: O2 deficiency
Type 2: high CO2 levels (more common)
What can very high levels of CO2 act as?
A narcotic
What affect does NA have on RR?
NA causes us to breathe more – sympathetic NS
How does hyperventilation cut cerebral blood flow?
Too much CO2 blown off –> vessels contract due to alkalosis
What is the only use of adrenaline in humans?
Prevent hypoglycaemia
How does progesterone affect ventilation?
Causes hyperventilation (increases ventilation rate)
What are present in peripheral joints relating to the respiratory system?
Sensory mechanoreceptors. When joints move, body anticipates greater need for oxygen.
What does the vagus nerve innervate?
Larynx (via laryngeal nerve),
Pharynx,
Lung,
Heart,
Liver,
Bowels
And is the nerve in the aortic body.
Parasympathetic control (ANS)
What is the volume of air left in the chest after a full expiration called?
Residual volume
What is the volume of air left in the chest after a normal expiration called?
Functional residual capacity
What is the functional residual capacity?
Volume of air that is still present in the lungs at the end of passive expiration.
What is FVC + FEV1?
FVC – forced vital capacity
FEV1 – forced expiratory volume in 1 second.
In obstructive lung diseases (such as asthma, COPD + chronic bronchitis) how is the FEV1/FVC ratio affected?
FEV1/FVC ratio reduced because FEV1 is reduced but FVC is normal.
In restrictive lung diseases (such as pulmonary fibrosis + scoliosis) how is the FEV1/FVC ratio affected?
Approx. normal because both FEV1 + FVC reduced.
Pulmonary irritant receptors (cough receptors) in the epithelium of the respiratory tract are sensitive to what?
Mechanical + chemical stimuli.
Where are pulmonary irritant receptors mainly located?
Trachea, pharynx, carina of trachea
When the cough receptors are triggered where does the impulse travel?
Via the recurrent laryngeal nerve –> superior laryngeal nerve –> vagus nerve –> medulla –> glottis, external intercostal nerves, diaphragm
What is partial pressure of a gas a measure of?
The concentration of a gas in a mixture of gases. Measured in mmHg or kPa.
Dissolved gasses exert partial pressure on other surfaces exerting pressure.
What is vital capacity (VC) + residual volume (RV)?
Total lung capacity (TLC)
What is tidal volume (VT) + inspiratory reserve volume + expiratory reserve volume?
Vital capacity
What can’t be measured by spirometry?
RV + FRC. A helium dilution method is used or plethysmography.
What does the coronary sinus receive + where from?
Left – great cardiac vein
Right – small + middle cardiac veins
When does an increased residual volume (RV) occur?
In emphysema, COPD, sometimes asthma
What is peak expiratory flow rate (PEFR)?
Measures airway obstruction by measuring FEV1
What is the driving force of gas transport?
Pressure gradients: -ve intrathoracic pressure –> ventilation + partial pressure differences.
Why is pressure in alveolar air lower than inspired air?
Water vapour dilutes amount of pressure exerted on gases. Rapid diffusion of air in alveoli.
What affects rate of diffusion of O2 + CO2 from aqueous lining of alveoli to blood?
Partial pressure of the gas, solubility of the gas in liquid, area available for exchange, thickness of alveolar membrane
Is pulmonary A. blood, oxygenated or deoxygenated?
Deoxygenated like systemic vein
In haemoglobin, what state is iron in?
Ferrous state (Fe2+)
What is pre-load?
Initial stretching of the cardiac myocytes prior to contraction.
Vol being returned to R side of the heart from systemic circulation.
Preload is stretch.
What is after-load?
Degree of resistance that the L ventricle must overcome to pump blood out of the heart.
Afterload is squeeze.
In which form(s) is CO2 transported in the blood?
70% - bicarbonate (HCO3-)
23% - carbaminohemoglobin (HbCO2)
7% - dissolved in blood (CO2)
What does carbonic anhydrase catalyse?
These are reversible reactions, it catalyses both.
H2O + CO2 –> H2CO3 –> HCO3- + H+ (tissues)
HCO3- + H+ –> H2CO3 –> H2O + CO2 (lungs, kidney)
How does: hyperventilation, hypoventilation, diabetic ketoacidosis, renal failure + vomiting change pH?
Hyperventilation, vomiting – alkalosis
Hypoventilation, ketoacidosis, renal failure – acidosis
Explain what happens in respiratory acidosis with metabolic compensation?
Lungs retain CO2 HCO3- rises + pH falls Kidney compensates by excreting H+ + retaining HCO3- This increases pH to normal levels But HCO3- + pCO2 remain high
Explain what happens in respiratory alkalosis with metabolic compensation?
Lungs lose excess CO2 HCO3- falls + pH rises Kidney compensates by retaining H+ + excreting HCO3- This decreases pH to normal levels But HCO3- + pCO2 remain low
Anatomically what is the upper respiratory tract?
Nose, nasal cavity, paranasal sinuses, pharynx
Functionally what is the upper respiratory tract?
Conducting zone: nose, pharynx, larynx, trachea, bronchi, bronchioles
Anatomically what is the lower respiratory tract?
Larynx, trachea, bronchi, lungs
Functionally what is the lower respiratory tract?
Respiratory zone: respiratory bronchioles, alveolar ducts, alveoli
What are the anterior + posterior apertures of the nose + nasal cavity?
Anterior – anterior nares (nostrils)
Posterior – posterior naris (choanae posterior – which open into the nasopharynx)
What is the nasal cavity separated into + from?
Into 2 nasal cavities – midline nasal septum
From oral cavity – hard palate
From cranial cavity – frontal, ethmoidal + sphenoidal bones
What are conchae (turbinates)?
Walls that divide both nasal cavity into 4 air channels by 3 curved shelves of bone (conchae) (project medially across nasal cavity).
What are the functions of the nasal cavity?
Olfaction; filter, humidify + warm inhaled air; provide an airway as a resonating chamber for speech
Name the 3 conchae + 4 nasal meatuses/recesses.
Spheno-ethmoidal recess Superior concha Superior nasal meatus Middle concha Middle nasal meatus Inferior concha Inferior nasal meatus
What is the function of the conchae?
Increase the surface area of contact between tissues of the lateral wall + inspired air.
Which 3 bones create the choanae (posterior aperture)?
Palatine bone, vomer, sphenoid bone
Name the 4 paranasal air sinuses.
Frontal sinuses, ethmoidal sinuses, spheroidal sinuses, maxillary sinuses.
Where are openings of the paranasal sinuses?
On the lateral wall + roof of nasal cavities.
What are paranasal sinuses lined by?
Respiratory mucosa (same as nasal cavity) – ciliated + mucus secreting
What innervates sinuses?
Branches of the trigeminal nerve (CN V)
What are the functions of sinuses?
Lighten skulls, increase resonance of voice, produce mucus
Summary of which meatus sinuses drain into.
Sphenoidal sinuses -
Posterior ethmoidal sinus -
Frontal sinus -
Maxillary sinuses -
Anterior and middle ethmoidal sinuses -
Nasolacrimal duct -
Sphenoidal sinuses - sphenoethmoidal recess meatus
Posterior ethmoidal sinus - superior meatus
Anterior and middle ethmoidal sinuses - middle meatus
Frontal sinus - middle meatus
Maxillary sinuses - middle meatus
Nasolacrimal duct - inferior meatus
Where does the sphenoidal sinuses drain into the nasal cavity?
Into the spheno-ethmoidal recess.
Where does the posterior ethmoidal sinus drain into?
Into the superior meatus.
Where do the frontal and maxillary sinuses drain into?
Into the middle meatus.
Where does the anterior + middle ethmoid air sinuses drain into?
Into the middle meatus.
Where does the nasolacrimal duct drain into?
Into the inferior meatus
What is sinusitis?
Inflammation of the sinuses. Sinuses are mucous lined so if there is a blockage, fluid will build up + infections can spread.
What are the most important arteries of the nasal cavity?
Septal branch of the: anterior + posterior ethmoidal artery, sphenopalatine, nasal artery from superior nasal labial artery + terminal part of greater palatine artery.
What is epistaxis + where does it occurs usually?
Bleeding from the nose, occurs at junction between septal branches of the superior nasal labial artery + sphenopalatine arteries.
What is the respiratory mucosa made up of?
Pseudostratified ciliated columnar epithelium + goblet cells.
What is the function if the respiratory mucosa?
Traps + moves unwanted bodies in correct direction (cilia) + warm inhaled air (mucus)
What specialised lining can be found in the nasal cavity?
Olfactory mucosa.
How is the pharynx bound?
Anteriorly – not bound
Inferiorly – cricoid cartilage
Superiorly – base of skull
Posteriorly – oesophagus
What are the 3 openings of the pharynx?
Nasal cavity, oral cavity, larynx.
How many regions does the pharynx have + what are they?
Nasopharynx – inferior to posterior apertures, bound by base of skull to uvula + soft palate.
Oropharynx – soft palate to epiglottis.
Laryngopharynx – epiglottis to cricoid.
What is the otitis media?
The inner ear
What role do tonsils play?
First line of defence against pathogens.
Where do adenoids (pharyngeal tonsils) lie?
Base of cranial cavity, on nasopharynx
Where do palatine tonsils lie?
Behind the uvula, below soft palate
What is the larynx inferior, superior + anterior to?
Inferior to – cricoid cartilage
Superior to – laryngeal inlet
Anterior to – oesophagus
What does the larynx connect?
The pharynx to the trachea
Name the 9 cartilages that join to form larynx.
3 unpaired – epiglottis, thyroid, cricoid
3 paired – arytenoid, cuneiform, corniculate
What the Adam’s apple?
Thyroid cartilage
What is the primary function of the larynx?
Vocalisation
What are the false + true vocal cords?
True folds – true vocal cords
False folds – vestibular folds (superior to true folds)
How does phonating work?
Vocal folds + arytenoid cartilages are adducted + air is forced through the close rima glottis.
Causes vocal folds to vibrate against each other + produce sounds.
What is the secondary function of the larynx?
Help with breathing, protection during swallowing
What narrows the rima glottidis?
Laryngeal muscles attached to the cartilages + elastic ligaments of vocal folds’ contract, they move the cartilage + pull elastic rights, narrowing the rima glottidis.
What occurs during deglutition?
Swallowing. Backward motion of the tongue forces epiglottis over glottis’ opening + prevent swallowed material entering the larynx + then the lungs.
Which nerve innervates the larynx?
Sensory + motor branches of the vagus nerves:
Recurrent laryngeal nerve + superior laryngeal nerve
Which muscle pulls the clavicles + rib cage upward?
Sternocleidomastoid.
In blood vessels, higher resistance + higher pressure gradient causes what?
Higher resistance – lower the flow.
Higher pressure gradient – higher the flow.
All the intrinsic muscles of larynx (except cricothyroid) are innervated by which nerve?
Inferior (recurrent) laryngeal nerve – terminal branch of superior laryngeal nerve
What nerve is the cricothyroid innervated by?
External branch of superior laryngeal nerve.
Name the intrinsic laryngeal muscles.
Posterior cricoarytenoid, lateral cricoarytenoid, thryoarytenoid, cricothyroid.
What are the extrinsic laryngeal muscles comprised of?
Suprahyoid + stylopharyngeus – elevate the larynx.
Infrahyoid – depress the larynx
What do the extrinsic laryngeal muscles act to move the larynx?
Move the larynx superior + inferiorly.
What do the intrinsic laryngeal muscles control?
Shape of rima glottidis, length + tension of vocal folds.
Flow is proportional to what?
To the 4th power of the resistance.
So, if you double the diameter of a tube, flow increases by 24 = 16-fold.
Tissue flow is determined by what?
Determined locally by tissue demand.
Why do tissues manipulate the resistance of blood flow?
BP is kept consistence + the tissues still get the flow they need.
How do tissues control flow?
By contracting + relaxing precapillary sphincters around the arterioles.
How is BP controlled in the long-term?
Pressure diuresis: increase urine output + reduce blood volume thus reducing BP
Renal control: RAAS
Other hormones: natriuretic peptides, ADH
What does renin do?
Renin turns Angiotensinogen to Angiotensin I.
Where is angiotensinogen released from?
Angiotensinogen release from liver.
Where is renin from?
Renin from juxtaglomerular cells in kidneys
Aldosterone leads to what?
Sodium + water retention.
What can you treat hypertension with?
Diuretics, beta-blockers -olol, calcium antagonists -ipine, ACE inhibitors -pril, ARBs (Ang receptor blockers) -sartan, Aldosterone inhibitors (spironolactone)
Which vessel layer has smooth muscle?
Tunica media. Also has external elastic lamina + associated connective tissue with collagen + elastin fibres
Where is vasa vasorum found?
Tunica externa
In which blood vessel layer is the endothelium found?
Tunica intima
Where is internal + external elastic lamina found?
Internal – between tunica intima + media
External – between tunica media + externa
Which arteries does the great, middle + small cardiac veins run along?
Great – anterior IVS
Middle – posterior IVS
Small – right marginal
What makes muscle contraction in smooth vessels (like blood vessels) different from skeletal muscle?
Smooth muscles don’t have sarcomeres; is a single cell, more sustained contraction, uses minimal ATP, can contract over a large range whereas skeletal muscle can only contract the size of the sarcomere.
What is the epithelium of vascular system made up of?
Simple squamous epithelium.
What are elastic arteries + muscular arteries?
Elastic – tunica media rich in elastin (large arteries)
Muscular – tunica media have more smooth muscle (smaller arteries + arterioles)
In which vessels is the tunica media almost absent?
Capillaries
Name the 3 types of capillaries.
Continuous (generic type), fenestrated, discontinuous (sinusoid).
Where are discontinuous (sinusoid) capillaries found?
In tissues where cell + molecules exchange (liver, spleen).
Where are fenestrated capillaries found?
In tissues with high exchange function (small intestines, kidney, endocrine glands).
Where are continuous capillaries found?
CNS, lungs, muscle tissue + skin.
When hydrostatic pressure is lower than blood colloidal osmotic pressure, what happens to fluid in peripheral tissues?
Fluid absorbed
What happens when hydrostatic pressure is greater than osmotic?
Fluid is filtered (exits capillaries)
What are cardiac myocytes joined via?
Intercalated disc containing gap + adherens junctions providing electrochemical coupling + mechanical linking
Which chamber(s) make up the left border of the heart?
LEFT ventricle
Which chamber(s) forms the right border of heart?
Right atrium
ANother name for coronary sulcus
atrioventricular groove
Divides atria from ventricles
In 60% of humans, which vessel supplies the SAN?
Right coronary artery. The AVN is also supplied by the right coronary artery in 80% of humans.
At which vertebral level does the inferior phrenic, celiac, superior mesenteric, middle suprarenal, renal, gonadal, lumbar, inferior mesenteric, media sacral + common iliac arteries branch off the abdominal aorta?
Inferior phrenic – T12, Celiac – T12, Superior mesenteric – L1,
Middle suprarenal – L1, Renal – L1, Gonadal – L2, Lumbar – L1-4,
Inferior mesenteric – L3, Median sacral – L4, Common iliac – L4
What is the function of the sinuses of Valsalva?
Promote coronary artery blood flow during diastole
Where does the anterior + posterior interventricular sulci run?
Vertically on their respective sides of the heart.
What can the transverse pericardial sinus be used for?
To identify + subsequently ligate the arteries of the heart during coronary artery bypass grafting.
Where is the mediastinum located?
Central compartment of the thoracic cavity, between the 2 pleural sacs
What makes up the floor of the mediastinum?
Floor – diaphragm
What makes up the posterior border of the anterior mediastinum?
Pericardium
Where is the thyroid gland located?
In the anterior neck – C5 to T1
What does azygous mean?
Unpaired
What does the azygous vein carry?
Runs up the side of the thoracic vertebral column, drains into superior vena cava.
Carries deoxygenated blood from posterior walls of thorax + abdomen.
Which vessels anastomose to form the posterior interventricular artery?
Right coronary and left circumflex
Which vessels does the left main stem divide into?
Anterior interventricular and left circumflex
Where does the coronary sinus lie?
Posterior atrio-ventricular groove
Vertebral arteries are direct branches of which artery?
Subclavian
Which vertebral levels does the posterior surface of the heart lie?
Between T5 + T8
What’s another name for visceral pericardium?
Epicardium
What lies between the 2 left + 2 right pulmonary veins?
Oblique pericardial sinus
What is the auricle?
Protrusion of the surface wall of each atrium.
Where does the coronary sinus drain into + what does it drain?
Receives blood from 3 main cardiac veins: great, middle + small. Drains into posterior of R atrium.
What are the musculi pectinati?
Parallel ridges in the walls of the atria of the heart.
What is the smooth + rough walls of the atrium called?
Smooth – sinus venarum.
Rough – musculi pectinate
Which valves have no chordae tendineae or papillary muscles?
Semilunar
How many pulmonary veins drain into the left atrium?
4
Where does the SAN lie?
Crista terminalis.
What is the function of the papillary muscles + chordae tendineae?
Papillary muscles are in ventricles, they attach to cusps of AV valves (tricuspid + mitral) via the chordae tendineae.
Papillary muscles contract, prevents inversion/prolapse of these valves, blood flow back to atria, on systole (ventricular contraction).
What happens when the papillary muscles contract?
The chordae tendineae become taut + close AV valves.
Prevents them from flipping back into the atria, and allow blood to flow back into the atria.
What are chordae tendineae?
Cord-like fibrous tendons.
Attach to mitral/tricuspid valves on one end + papillary muscles on the other.
What arteries does the R coronary artery give off?
Marginal A. – branches off at inferior border to apex Posterior descending (interventricular) A.
What does the R coronary artery run along?
The R atrioventricular groove
What does the R coronary artery supply?
R atrium, R ventricle,
posterior 1/3 of interventricular septum
What does the L coronary artery supply?
L atrium, L ventricle,
anterior 2/3 of interventricular septum
Where does the visceral + partial pleura join?
Hilum
How many lobes and fissures does the right lung contain?
2 fissures: horizontal + oblique (horizontal more superior)
3 lobes: superior, middle, inferior
How many lobes and fissures does the left lung contain?
1 fissure: oblique
2 lobes: superior + inferior
Which lobe of the lung is entirely at the front?
RML (right middle lobe)
In which position is the pulmonary artery relative to the bronchus in the R + L hilum?
R hilum – pulmonary A. anterior to bronchus
L hilum – pulmonary A. superior to bronchus
List the 3 main divisions of the celiac trunk.
L gastric artery
Common hepatic artery
Splenic artery
Which arteries supplies the duodenum?
Superior part – celiac artery
Inferior part – superior mesenteric artery
Name the main branches of the abdominal aorta.
Celiac trunk
Superior mesenteric artery
Inferior mesenteric artery
What does the superior + inferior mesenteric arteries anastomose via?
Marginal artery of colon
Where does the R gastric A. arise from?
The proper hepatic artery
Name the branches of the L gastric A.
Oesophageal branch + stomach branch.
Which arteries give off the supra renal arteries?
Inferior phrenic
Which arteries supply the lungs?
Bronchial arteries
Which arteries supplies the lungs deoxygenated blood?
Pulmonary arteries
Which phrenic nerve innervates diaphragm from above + which innervates from below?
L – above
R – below
What is oncotic pressure?
The force exerted by attraction of water molecules to plasma proteins that are unable to pass through capillaries.
What is hydrostatic pressure?
Pressure that blood exerts in the capillaries so fluid moves out through pores into the interstitial space.
Why are ribs 11 + 12 known as the floating ribs?
Because they do not attach to the sternum at all.
Which ribs are known as the true ribs + why?
1-7; because they attach to sternum via their own costal cartilage
Which ribs are known as the false ribs + why?
8-12; because they don’t attach to sternum via their own costal cartilage.
