Question | Answer |
Which CA supplies the SAN? | Right CA:60%
Left CA 40% |
Which CA supplies the AVN? | Right CA |
Where does the ascending aorta lie in the mediastinum? | Pericardial sac at lower edge of CC3 and CC2 |
Where does the IVC pass through the diaphragm? | T8 |
Explain MAP relative to SV | MAP = CO x TPR
CO = HR x SV |
Describe the process that occurs when CO2 increases | Central chemoreceptors react and increase breathing rate accordingly |
Describe the blood flow pathway | SVC,IVC,CA --> Right atrium -->Tricuspid Valve --> Right Ventricle -->Pulmonic valve -->Pulmonary artery -->Lungs --> Pulmonary veins x4 --> Left atrium --> Mitral valve --> Left ventricle --> Aorta |
How does chronotropic agents work? | Alters the rate of decay |
How does inotropic agents works? | Affects the contractility of the heart |
How does Beta Receptors increase the heart rate? | Stimulates adenylate cyclase--> cAMP --> protein kinases --> HCN |
Name the hormonal controls of blood pressure | ADH, RAAS, Catecholamines, ANP, and NO |
An increase in BP is detected by? Where is it located and how does it work? | Baroreceptors located in the carotid sinus and aortic arch. These are detected by the glossopharyngeal nerve and the vagus nerve |
An increase in pH is detected by? Where is it located and how does it work? | Peripheral chemoreceptors located in the carotid body and the aortic body . Theses work by depolarizing and exocytose neurotransmitters |
Think of the graph for the AP of cardiomyocytes. Now label it | Phase 4: Sodium and Calcium channels are closed.Potassium channels are open
Phase 0: Fast Sodium channels open
Phase 1: Transient potassium channels open
Phase 2: L type Calcium VGC open = Efflux of potassium
Phase 3: Calcium VGC close,K repolarize |
How does the body react for: an increase of BP | Baroreceptors detect the increase and parasympathetic nervous system is activated. ACh binds to muscarinic 2 receptors and cause vasodilation |
How does the body react for: a decrease in BP | Baroreceptors detect this and sympathetic nervous system is activated. NE and E is released which binds to beta 1 receptors and cause vasoconstriction |
How does the body react for: an increase in pH | Central chemoreceptors communicate with the resp. centre and increase breathing rate |
What does QRS represent? | Ventricular depolarization |
What does the P wave and T wave represent? | Atrial depolarization and Ventricular repolarization |
Name the pathway of blood for fetuses | Vitelline, Umbilical & Cardinal veins --> Sinus venous --> Primordial Atrium --> Atrioventricular canal --> Primordial ventricle --> Bulbus Cordis --> Truncus arteriosus --> Aortic Sac --> Aortic arches |
Where is the SAN located? | Upper part of the right atrium |
Where is the AVN located? | Above coronary sinus on interatrial septum |
What is the conus arteriosus? | Infundibulum located at the upper front part of the right ventricle connects to pulmonary trunk |
Name the shunts in the fetal circulation | Foramen ovale, Ductus Arteriosus, Ductus Venosus |
What causes the closing of the foramen ovale, ductus arteriosus and ductus venosus | Increase of pressure in the left ventricle closes the foramen ovale. Lungs release bradykinin to close the ductus arteriosus. |
What do positive chronotropes do? Name an example | NE, Increases the rate of decay, thereby increasing heart rate |
What do negative chronotropes do? Name an example | ACh, decreases decay which then decreases heart rate |
What do positive inotropes do? Name an example | Increase contractility, NE |
What do negative inotropes do? Name an example | Decrease contractility, Acidosis |
How does beta 1 receptors work? | Increase HR, Contractility, renin release. Stimulates adenylate cyclase --> cAMP --> Protein kinases --> HCN |
How does the sympathetic nervous system work? | Adrenergic nerves release NE and E, Adrenoreceptors bind NE and E, Beta 1 adrenoreceptor increases stimulation of HCN channels |
How does the parasympathetic nervous system work? | ACh binds to M2 muscarinic receptors that decrease adenylate cyclase which then decreases HR, SV and causes vasodilation |