Lecture 23 & 24 & 25: Digestive System Flashcards
Digestive system
Organs involved in ingestion, digestion of food, absorption of nutrients, elimination of indigestible materials
Provides nutrients for cells for energy, growth, repair
Alimentary canal
Muscular tube from mouth to anus, 9m long
Composed of oral cavity, pharynx, esophagus, stomach, small intestine, large intestine, rectum
Accessory digestive organs
Assist in ingestion and digestion of food
Composed of teeth, tongue, salivary glands, liver, gallbladder, pancreas
Oral cavity
Bound by mucosal folds (lips) made of orbicularis oris
Roof: anterior 2/3 hard palate (maxilla and palatine bones), and posterior 1/3 soft palate (separating the oral cavity and nasopharynx during swallowing)
Posterior border: uvula - conical soft tissue
Floor: suprahyoid muscle
Behind oral cavity is pharynx
Border between oral cavity and pharynx: oropharyngeal isthmus
Dental arch
Vestibule: part of oral cavity outside dental arch (horse shoed shape)
Oral cavity proper: remaining space behind dental arch
Frenulum
Short mucosal folds that attach lips or tongue to gum
Upper lip attached via superior labial frenulum
Lower lip attached via inferior labial frenulum
Tongue attached via lingual frenulum
Function: prevent excess movement of lips/tongue
Palatoglossal arch
From posterior border of soft palate are 2 folds
Connects soft palate to tongue; anterior fold
Palatopharyngeal arch
Connects soft palate to wall of pharynx; posterior fold
Tonsilar fossa
Between the palatoglossal arch and palatopharyngeal arch
Contains the palatine tonsil
Oral pharyngeal isthmus
Connects oral cavity proper to oropharynx
Formed by palatoglossal arches
Composition of teeth
Crown: above level of gum/gingiva
Neck: narrow part of tooth in touch with gingiva connecting crown and root
Root: embedded in alveolar bone of upper/lower jaw; attaches cementum to alveolar bone via periodontal ligament
Calcified tissues of teeth
Dentin: makes up core, calcified tissue
Enamel: extra protection in the crown region
Cementum: extra protection in the root region
Pulp cavity
Large space in dentin
Contains loose connective tissue, blood vessles, nerves, lymphatic vessels
Root canal: extension of pulp cavity in root
Nerve supply of teeth
Branches of CNV through root canal and pulp cavity
Tongue
Superior surface: dorsal surface
Posterior end: epiglottis and entrance of larynx
Involved in swallowing, phonation, tasting, chewing
Dorsal surface of tongue
Terminal sulcus: reverse V shaped line dividing tongue into posterior 1/3 or root of tongue or pharyngeal part of tongue, and anterior 2/3 or body of tongue or oral part of tongue
Anterior 2/3 of tongue
Made of skeletal muscles
Has epithelial papilla
Circumvallate papilla: largest, single row in front of terminal sulcus
Foliate papilla: on L/R border of tongue
Fungiform papilla: evenly scattered on dorsal surface, looks like mushrooms
Filiform papilla: small, thin
All papillae except filiform papilla contain taste buds
Filiform papilla increase friction of tongue to move bolus around oral cavity more efficiently
Posterior 1/3 of tongue
Primarily made up of lymphoid tissue
Contains lingual tonsils
Nerve supply of tongue
Anterior 2/3:
CNVII provides special taste
CNV provides general sense (pain, touch, temperature)
Posterior 1/3:
CNIX provides special taste and general sense
Esophagus
Muscular tube, 25cm
Starts at CVI (end of laryngopharynx) through neck, superior and posterior mediastinum, diaphragm, and ends at stomach at TXi
Borders of esophagus
Posterior: lower cervical and thoracic vertebrae
Anterior: trachea and L atrium of heart
Left: arch of aorta which continues as descending aorta