Govt Exams
Parkinson's disease results from loss of dopaminergic neurons in the substantia nigra, causing dopamine deficiency and characteristic motor symptoms.
Pepsin is a protease activated in the acidic stomach environment, cleaving peptide bonds in proteins to form polypeptides and oligopeptides.
Aldosterone, released by the adrenal cortex, increases sodium reabsorption via mineralocorticoid receptors in the DCT and collecting duct.
Pulmonary surfactant (lipid + protein) reduces surface tension in alveoli, preventing their collapse during expiration and reducing work of breathing.
The kidneys produce approximately 90% of EPO, which stimulates red blood cell production in bone marrow when oxygen levels are low.
The loop of Henle creates a countercurrent multiplier system that establishes an osmotic gradient, enabling selective water reabsorption in the collecting duct.
Acetylcholine is the primary neurotransmitter at the neuromuscular junction, binding to nicotinic receptors on muscle fiber membranes to trigger muscle contraction.
Tidal volume, the volume of air inspired or expired during normal quiet breathing, is approximately 500 mL in adults.
The loop of Henle, particularly the descending and ascending limbs, creates a countercurrent multiplier system that establishes an osmotic gradient necessary for concentrated urine formation.
The SA node has the highest inherent rate of spontaneous depolarization (60-100 bpm), allowing it to set the rhythm for the entire heart.