HUMAN ANATOMY II STUDY NOTES. At the end of this chapter the student should be able to answer the following questions:

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1 HUMAN ANATOMY II STUDY NOTES CHAPTER ONE The Special Senses Learning objectives At the end of this chapter the student should be able to answer the following questions: 1. What is the gross and histological anatomy of the organ of taste? 2. What is the gross and histological anatomy of the organ of smell? 3. What is the gross and histological anatomy of the organ of vision? 4. What is the gross and histological anatomy of the organ of hearing and balance? Page 1

TASTE (tongue) The tongue is essentially a mass of skeletal muscle covered by mucous membrane, and with a midline fibrous septum separating the two muscular

2 TASTE (tongue) The tongue is essentially a mass of skeletal muscle covered by mucous membrane, and with a midline fibrous septum separating the two muscular halves. It has a dorsum, tip, inferior surface and not or just pharyngeal (root) 1/3 and oral (body) 2/3 separated by the sulcus terminalis. Page 2

3 The epithelium is stratified squamous type is keratinized in the oral part and non keratinized part and under surface. The mucous membrane is strongly adherent to the underlying muscle. The lower (ventral) surface is smooth but on the dorsal surface it is irregular with elevations called papillae. (i) FIliform Papillae elongated conical shape. They are numerous and present over the entire surface of tongue giving it a velvety (ii) appearance (has no taste buds). Fungiform Papillae. These resemble mushroom in that they have narrow stalk and smooth dilated upper part (has few taste buds). (iii) Are numerous towards the edges of the tongue. Foliate Papillae closely packed folds along the posterior lateral margins of the tongue. They contain numerous taste buds. Ducts from serous glands drain through openings positioned around (iv) their base. Circumvallate papillae large circular papillae whose flattened surface extend above other papillae. Are about a dozen in number and are arranged in the form of a V with the apex pointing backwards just in front of the an ill defined shallow groove, the sulcus terminalis, which marks the junction of the oral and pharyngeal parts of the tongue. In summary the taste buds are contained in the fungiform, foliate and circumvallate papillae on the tongue. In the adult, nearly all taste buds are on the tongue and its associated papillae, except for a few residual taste buds on epiglottis, palate and adjacent areas of the pharynx. Microscopically the taste buds appear onion shaped, with a small opening in the epithelium immediately over the taste bud is called the taste pore. Human have an average 10,000 taste buds. Page 3

4 Cranial nerves responsible for transmitting the sense of taste to the CNS - Facial nerve (anterior part of the tongue). Glossopharyneal nerve (posterior part of the tongue). Blood supply lingual artery and vein. Artery is from external carotid. All muscles of the tongue; intrinsic and extrinsic are supplied by the hypoglossal nerve except palatoglossus pharyngeal plexus. SMELL The olfactory mucosa, containing the bipolar primary olfactory neurons and their receptors lies in the superior recesses of the nasal cavity, immediately below the cribriform plate of the ethmoid bone. Nasal Cavity External opening Nostril Posterior opening cloanal Inferior hard palate Superior Anterior part of cranial base The 1 olfactory neuron synapse at the olfactory bulb, the olfactory bulb neurons project to the olfactory centers in the uncus and parahippocampal gyrus. Histologically the olfactory mucosa contains 4 types of cells: (i) Supporting cells (ii) Basal (iii) Primary olfactory neuron (iv) Immature differentiating olfactory neuron. Bowman s glands the glands of the mucosa, their ducts open onto the mucosal surface, secrete a soluble, olfactory specific protein, the odorant binding protein (OBP). (i) Concentrate the odorant near the receptor Page 4

5 (ii) (iii) (iv) May act as a carrier for odorants that by themselves are not soluble in the aqueous-based mucus. May function as a scavenger protein that remove odorants from solution in the mucosa. Function - sensory transduction involving Go protein, Camp, Cranial nerve olfactory nerve. EYE Page 5

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7 This is a SAMPLE (Few pages have been extracted from the complete notes:-it s meant to show you the topics covered in the full notes and as per the course outline Download more at our websites: To get the complete notes either in softcopy form or in Hardcopy (printed & Binded) form, contact us on: Call/text/whatsApp / naarocom@gmail.com info@naarocom.com sales@naarocom.com Get news and updates by liking our page on facebook and follow us on Twitter Sample/preview is NOT FOR SALE Page 7

Dorsum of the tongue. Oral Part exhibit lingual papillae of the 4 types. Oral Part of Tongue divided into Left & right halves by shallow median groove

Dorsum of the tongue. Oral Part exhibit lingual papillae of the 4 types. Oral Part of Tongue divided into Left & right halves by shallow median groove Histology of TONGUE Figure 22.13 Dorsum of the tongue Oral Part of Tongue divided into Left & right halves by shallow median groove Oral Part exhibit lingual papillae of the 4 types a. filiform papillae,