Study Notes

Pioneer bacteria invade dentinal tubules before clinical signs Tubules contain pure forms: One tubule → cocci Adjacent tubule → bacilli or threads No mixed forms within a single tubule…

Laxatives and cathartics (purgatives) Constipation is a common problem in older adults and laxatives are often used or overused. Non drug measures to prevent constipation (e.g. increasing intake of fluid and high–fiber foods, exercise) are much preferred to laxatives. Laxatives and cathartics are drugs used orally to evacuate the bowels or to promote bowel elimination (defecation). Both terms are used interchangeably because it is the dose that determine…

Respiration involves several components: Ventilation - the exchange of respiratory gases (O2 and CO2) between the atmosphere and the lungs. This involves gas pressures and muscle contractions. External respiration - the exchange of gases between the lungs and the blood. This involves partial pressures of gases, diffusion, and the chemical reactions involved in transport of O2and CO2. Internal respiration - the exchange of gases between the blood and the sys…

Ethosuximide (Zarontin): use in absence seizures (may exacerbate tonic-clonic seizures) Mechanism: ↓ T-type Ca currents in thalamic neurons, inhibits bursts of APs, ↓ synchronous neuronal firing i.    Thalamo-cortical reverberating circuits: during absence type seizures, have reverberating circuits between cerebral cortex and thalamus at 3 Hz maintained by T-type Ca channels (since blocking these channels blocks the reverberating circuit…

Clinical Physiology  Heart Failure : Heart failure is inability of the heart to pump the enough amount of blood needed to sustain the needs of organism . It is usually called congestive heart failure ( CHF) . To understand the pathophysiology  of the heart failure ,  lets compare it with the physiology of the cardiac output : Cardiac output =Heart rate X stroke volume Stroke volume is determined by three determinants : Preload ( venous retu…