Kluver-Bucy Syndrome
Kluver-Bucy Syndrome is a rare neurobehavioral disorder associated with bilateral destruction of the anterior part of the temporal lobes of the brain. This removes not only, portions of temporal cortex but also of the amygdalas that lie inside these parts of the temporal lobe. Anatomic Basis: Amygdala lies deep within medial temporal lobes of the […]
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Lesions of Upper Motor Neurons and Lower Motor Neurons
Upper Motor Neurones (UMN), Lower Motor Neurone (LMN) and their Lesions All the neurons contributing to the pyramidal and extrapyramidal systems should be called upper motor neurons (UMN). The anterior horn cells and the related neurons in the motor nuclei of some cranial nerves are called lower motor neurons (LMN). Axons of these cells give […]
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Resting Membrane Potential, Action Potential and Ionic Basis
Resting Membrane Potential (RMP) There exists a potential difference across the cell membrane in all the living cells in resting conditions which is known as resting membrane potential. The value of RMP normally varies from 5 millivolts(mV) to -100 millivolts(mV). The value mainly depends upon the type of the cell. The value of RMP in […]
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Renal Counter Current Mechanism Made Simple
Introduction: Countercurrents exist when fluids flow in opposite directions in parallel and adjacent tubes. There are 2 countercurrent systems and an osmotic equilibrating device: Countercurrent multiplier (Loop of Henle): Establishes gradient of osmolarity from cortex (300mOsm/L) to the papilla (1200mOsm/L) aided by Urea recycling Countercurrent exchanger (Vasa recta): Maintains the corticopapillary osmotic gradient established by […]
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Cardiac Cycle
Definition: Cardiac cycle refers to the cardiac events that occur from the beginning of one heart beat by spontaneous generation of action potential in SA node to the beginning of the next. When the heart rate is 75/min, the period of one cardiac cycle is 0.8 sec. Important terms: Diastole: a period of relaxation during […]
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Function of Juxtaglomerular Apparatus (JGA)
Juxtaglomerular Apparatus or Complex is a specialized region of a nephron where the afferent arteriole and Distal Convoluted Tubule (DCT) come in direct contact with each other. Juxtaglomeruar Apparatus (JGA) consists of: 1) Juxtaglomerular cells (modified smooth muscle cells) of afferent arteriole including renin containing (synthesizes and stores renin) and sympathetically innervated granulated cells which […]
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Auscultatory gap in hypertension
Sometimes during manual blood pressure measurement by auscultatory method, after a few initial tapping sounds, no sound is heard for a variable duration and then the sounds are heard again. This period when no sound is heard is called as auscultatory gap. Korotkoff sounds: When the cuff pressure is great enough to close the artery […]
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Lung Volumes, Capacities and Dead Space
Lung Volumes, Capacities and Dead Space- Definitions and Normal values . Knowledge of these values are quite important to understand respiratory physiology, pathological basis of various respiratory illnesses and for anesthesia. Tidal Volume (TV)- Volume of gas inspired or expired in each breath during normal quiet respiration. It is 400-500 ml ie 10ml/kg Inspiratory Reserve Volume ( […]
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Mechanism of Cough and Sneeze
Receptors Extrathoracic: nose, oropharynx, larynx, upper trachea Intrathoracic: rapidly adapting irritant receptors in epithelium of lower trachea and large central bronchi Other locations: tympanic membrane, diaphragm, stomach Cough Reflex: Cough is an expulsive reflex that protects the lungs and respiratory passage from foreign bodies. Causes of cough: Irritants-smokes, fumes, dusts, etc. Diseased conditions like COPD, […]
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