Electro Encephalogram Electro Encephalogram is the graphic record of electrical activity of the brain recorded from the surface. Technique is known as Electro Encephalography. It is the recording of the potential difference as rhythm (frequency) and magnitude. Rhythm of the EEG are designated as alpha, beta, theta and delta rhythm. Alpha rhythm Frequency Amplitude Characteristics […]

Physiology of Sleep Sleep is a state of reversible unconsciousness and relative immobility of an animal. It is due to temporary inhibition of the reticular activation system of the ascending reticular formation, which in turn reduces the normal excitability of the cortex. Sleep centres are located in the pons and medulla known as raphe nuclei.

Micturition reflex Micturition reflex is the complex phenomenon involves initiation from stretch receptors in the bladder wall. Axons have their cell bodies located in the sacral spinal ganglia and dorsal grey column of the spinal sacral segments. Stretching of the bladder stimulate the sensory fibres which in turn causes the generation of action potential that

Sneeze reflex Sneeze reflex is a protective reflex to remove the irritant stimuli. Receptors are present in the upper respiratory pathway. Sensory information passes via trigeminal to the BSRF. The efferent via vagus, trigeminal and facial effect sneezing. 

Cough reflex Cough reflex is a protective reflex  to remove the irritant from the respiratory tract. Receptor for this reflex is from respiratory tract. Irritation of any part of the respiratory tract serve as sensory impulse. Vagus is the sensory nerve to endup in BSRF via Fasciculus solitarius nucleus. Efferent nerve via vagus project to

Mastication reflex Reflex activity under the control of brain stem. Mastication is basically voluntary but usually takes place involuntarily. Mastication reflex or chewing reflex is by the rhythmic movement of the mandible. Lowering of the mandible due to the extension of the tongue is known as linguo mandibular reflex. Stimuli for masticatory reflex is the presence of

Swallowing reflex Swallowing centre is located in the brain stem (medulla oblongata). Stimulation of the receptors in the soft palate, pharynx (posterior wall) and epiglottis (dorsal surface) by food material initiate this reflex. It is a complex multi synaptic reflex involving pharyngeal and oesophageal stage. Sensory fibres pass through trigeminal, glossopharyngeal and vagus nerve. This

Salivatory reflex Salivatory reflexes is initiated by many difference stimuli ans is potentiated by olfactory, gustatory, auditory and visual mechanism. Protective reflex preventing oral mucosa from drying. Elicited when oral and lingual mucosa is stimulated by foreign substances. Afferent fibres pass via trigeminal, facial, glossopharyngeal and vagus. These fibres end in brain stem reticular formation

Suckling reflex Suckling is a physiological process involving  coordinated synchronus movement of tongue and buccal musculature. More prominant in newborn animals to fecilitate withdrawal of milk from teat canal and mammary gland while feeding. It is termed as a reflex since it involves set pattern of neuronal inputs to complete this action. Afferent fibers pass

Emetic reflex Emesis is the regurgitation of materials from stomach and upper intestine through oesophagus to oral cavity.