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Category Archives: Anatomy

Urinary Concentration – The Medullary Osmotic Gradient


The kidneys can produce a range of urine osmolalities depending on the levels of ADH. The production of hypo-osmotic urine is an understandable process: The tubules (particularly the thick ascending limb of Henle's loop) reabsorb relatively more solute than water, and the dilute fluid that remains in the lumen is excreted. The production of hyperosmotic […]

[Histology] Basic Four Types of Tissues – Connective Tissues


The different types of connective tissue maintain the form of organs throughout the body. Differences in composition and amount of the cells, fibers, and ground substance make up variety of connective tissue types. Connective tissues provide a matrix that supports and physically connects other tissues and cells together in organs. The interstitial fluid of connective […]

[Anatomy] Motor Pathways


Somatosensory Pathways Motor pathways are formed from the cerebral nuclei, the cerebllum, descending projection tracts, and motor neurons. Descending project tracts are motor pathways that originate from the cerebral cortex and brainstem. There are at least two motor neurons in the somatic motor pathway: an upper motor neuron and a lower motor neuron. Motor neurons […]



Reflex are rapid, automatic, involuntary reactions of muscles (cardiac, smooth, and skeleton) or glands to a stimulus. All reflexes have similar properties: A stimulus is required to initiate a response to sensory input. A rapid response requires that few neurons be involved and synaptic delay be minimal. A preprogrammed response occurs the same way every time. […]

[Anatomy] Sensory Pathways


The CNS communicates with peripheral body structrues through pathways. These pathways conduct either sensory or motor information; proccessing and integration occur continuously along them. These pathways travel through the white matter of the brainstem and/or spinal cord as they connect various CNS regions with cranial and spinal nerves. A pathway consists of a tract and […]