ANAPHY

• The Digestive System is composed of organs whose primary functions are ingestion, digestion, absorption of food and excretion of undigested food.
• The Digestive System includes the mouth, pharynx, esophagus, stomach, small and large intestines and the accessory digestive organs such as the liver, pancreas and gall bladder.
• The walls of the Digestive tract are composed of the Tunica mucosa, which functions as an absorptive, secretory, and protective layer, and consists of the epithelium, lamina propria, muscularis mucosa, submucosa, and tunica serosa.
• The Tunica mucosa is lined by simple columnar epithelium except for the mouth, pharynx, esophagus, and lower anus which are lined by stratified squamous non-keratinized epithelium.
• The Tunica mucosa also consists of the lamina propria, a loose areolar tissue, and the muscularis mucosa, a layer of smooth muscles.
• The Tunica serosa is the Visceral peritoneum, a single layer of simple squamous epithelium which secretes a small amount of serous lubricating fluid which reduces friction among the GI tract organs and the body wall.
• The Digestive tract consists of the Oral cavity, Pharynx, Esophagus, Stomach, Small intestines, and Large intestine.
• The Oral cavity includes the Oral vestibule, Oral cavity proper, and Teeth.
• The Oral vestibule is the space bounded anteriorly by lips and cheeks and posteriorly by teeth and gums.
• The Oral cavity proper is the space bounded by gums and teeth, with the floor being the tongue and the roof being the hard and soft palate.
• The Teeth are two sets: Deciduous teeth, or temporary (milk), and Permanent teeth.
• The Deciduous teeth erupt on the average between 6 and 24 months after birth and are usually shed between the ages of 6 and 12.
• The Permanent teeth, or third molars, are the wisdom teeth, which are usually the last teeth to erupt and are located in the back of the mouth.
• The tongue is an organ for speech and mechanical digestion of food, and contains Papillae and Taste buds.
• The center of the ventro-postero-lateral nucleus of thalamus is Brodmann's area 3, 1, 2, which is the side contralateral to N1.
• Fasciculus Cuneatus is a nerve fiber bundle that carries impulses arising from the upper extremity, entering the spinal cord through upper thoracic segments.
• Fibers in the crude touch pathway synapse with dorsal root ganglion cells.
• The posterior spinocerebellar tract relays proprioceptive information regarding the status of individual muscle at the lower extremity.
• Fasciculus Gracilis is a nerve fiber bundle that carries impulses coming from the lower extremity, entering the spinal cord through the sacral, lumbar and lower thoracic segments.
• Clinical signs of injury to the lemniscal pathway include inability to recognize limb position, astereognosia, loss of vibration sense, loss of two-point discrimination, and positive Rhomberg’s sign.
• Fibers in the crude touch pathway will continue to ascend until they terminate at the ventral posterolateral nucleus of thalamus.
• Crude touch, also known as light touch pressure, is a pathway that involves the ventral/anterior spinothalamic tract, Meissner's corpuscles, Merkel's discs, and hair follicle nerve endings.
• N1 refers to the dorsal root ganglion, where axons of dorsal root ganglion make synapses with neurons in the spinal cord.
• The anterior spinocerebellar tract relays proprioceptive information regarding the status of group of muscles at the lower extremity.
• N2 refers to laminae VI, VII, VIII (ATP), where axons from the laminae will ascend as the ventral spinothalamic tract on the contralateral side.
• N3 refers to the ventro-postero-lateral nucleus of thalamus, where fibers are projected into the primary somesthetic areas 3,1,2 of the postcentral gyrus.
• The nerves of the tongue include the General sensory nerve for touch, which is located in the anterior 2/3 of the tongue, and the Glossopharyngeal nerve, which is located in the post-auricular area.
• The menstrual phase of the female reproductive cycle lasts for 3-5 days and is the first day of the cycle.
• If the oocyte is fertilized, the corpus luteum can persist up to 2 weeks due to Human Chorionic Gonadotropin produced by the placenta.
• Ovulation is the release of the secondary oocyte into the fallopian tube, usually during the 14th day of a 28-day cycle.
• If the oocyte is not fertilized, the corpus luteum degenerates in 10 to 12 days’ time forming corpus albicans.
• During the menstrual phase, estrogen and progesterone levels in the blood decrease, causing ischemia of the functionalis leading to menstruation.
• The preovulatory phase (proliferative) of the female reproductive cycle is between menstruation and ovulation and is more variable in length.
• After ovulation, LH stimulates the remnants of the mature graafian follicle to develop into the corpus luteum.
• Progesterone is secreted by the corpus luteum and acts synergistically with estrogen, preparing the endometrium for implantation and mammary gland for milk production.
• The post ovulatory phase of the female reproductive cycle is a constant phase lasting for 14 days in a 28-day cycle.
• The repair of the endometrium during the preovulatory phase involves the cells of the basalis forming new functionalis.
• During the preovulatory phase, the dominant follicle is selected to mature and estrogen and inhibin are secreted by the dominant follicle, stopping FSH secretion to prevent other follicles from growing.
• The endometrium thickens and edema formation occurs for preparation of implantation during the post ovulatory phase.
• The corpus luteum secretes progesterone and some estrogen.