digestive system Flashcards

Question

what is muscularis mucosae?

Answer 1

 Smooth muscle that produces local movements of mucosa

Answer 2

– Consists of areolar connective tissue – Contains blood and lymphatic vessels, lymphoid follicles, and submucosal nerve plexus that supply surrounding G I tract tissues – Has abundant amount of elastic tissues that help organs to regain shape after storing large meal

Answer 3

– Muscle layer responsible for segmentation and peristalsis – Contains inner circular muscle layer and outer longitudinal layers  Circular layer thickens in some areas to form sphincters

Answer 4

– Outermost layer, which is made up of the visceral peritoneum  Formed from areolar connective tissue covered with mesothelium (single layer of squamous epithelium) in most organs  Replaced by fibrous adventitia in esophagus – Dense connective tissue that holds esophagus to surrounding structures  Retroperitoneal organs have both an adventitia and a serosa

Answer 5

– Arteries that branch off aorta to serve digestive organs  Hepatic, splenic, and left gastric arteries  Inferior and superior mesenteric arteries – Hepatic portal circulation  Drains nutrient-rich blood from digestive organs  Delivers blood to liver for processing

Answer 6

G I tract nervous system and it is also called gut brain.

Answer 7

* Gut brain is made up of enteric neurons that communicate extensively with each other – Major nerve supply to G I tract wall that controls motility – Enteric neurons make up bulk of two main interconnecting intrinsic nerve plexuses: – Submucosal nerve plexus  Regulates glands and smooth muscle in mucosa – Myenteric nerve plexus  Controls G I tract motility

Answer 8

mediated by enteric nerve plexuses (gut brain); respond to stimuli in G I tract

Answer 9

respond to stimuli arising inside or outside of gut, such as from autonomic nervous system  Parasympathetic system enhances digestive process  Sympathetic system inhibits digestion

Answer 10

digestive, effector and neurons activity

Answer 11

* Digestive activity is provoked by a range of mechanical and chemical stimuli – Receptors located in walls of G I tract organs – Respond to stretch, changes in osmolarity and p H, and presence of substrate and end products of digestion

Answer 12

* Effectors of digestive activity are smooth muscle and glands – When stimulated, receptors initiate reflexes that stimulate smooth muscle to mix and move lumen contents – Reflexes can also activate or inhibit digestive glands that secrete digestive juices or hormones

Answer 13

* Neurons (intrinsic and extrinsic) and hormones control digestive activity – Nervous system control  Intrinsic controls: involve short reflexes (enteric nervous system)  Extrinsic controls: involve long reflexes (autonomic nervous system) – Hormonal controls  Hormones from cells in stomach and small intestine stimulate target cells in same or different organs to secrete or contract

Answer 14

* Associated organs include: – Mouth – Tongue – Salivary glands – Teeth

Answer 15

* Also called the oral (buccal) cavity – Bounded by lips anteriorly, cheeks laterally, palate superiorly, and tongue inferiorly – Oral orifice is the anterior opening – Walls of mouth lined with stratified squamous epithelium  Tough cells that resist abrasion  Cells of gums, hard palate, and part of tongue are keratinized for extra protection

Answer 16

– Lips (labia): composed of fleshy orbicularis oris muscle – Cheeks: composed of buccinator muscles – Oral vestibule: recess internal to lips and cheeks, external to teeth and gums – Oral cavity proper: lies within teeth and gums – Labial frenulum: median attachment of each lip to gum

Answer 17

– Palate forms the roof of the mouth and has two distinct parts

Answer 18

formed by palatine bones and palatine processes of maxillae with a midline ridge called raphe – Mucosa is slightly corrugated to help create friction against tongue

Answer 19

fold formed mostly of skeletal muscle – Closes off nasopharynx during swallowing – Laterally, soft palate anchored to tongue by palatoglossal arches – Also anchored to wall of oropharynx by palatopharyngeal arches – Area in between two arches is called fauces * Palatine tonsils are located in fauces

Answer 20

: fingerlike projection that faces downward from free edge of soft palate

Answer 21

* Tongue occupies floor of mouth * Composed of interlacing bundles of skeletal muscle * Functions include: – Gripping, repositioning, and mixing of food during chewing – Formation of bolus, mixture of food and saliva – Initiation of swallowing, speech, and taste * Intrinsic muscles change shape of tongue * Extrinsic muscles alter tongue’s position

Answer 22

attachment to floor of mouth * Superior surface bears papillae, peglike projections of underlying mucosa

Answer 23

gives tongue roughness to provide friction; only one that does not contain taste buds; gives tongue a whitish appearance

Answer 24

mushroom shaped, scattered widely over tongue; vascular core causes reddish appearance of tongue

Answer 25

: 8–12 form V-shaped row in back of tongue

Answer 26

located on lateral aspects of posterior tongue

Answer 27

groove located posterior to vallate papillae – Marks division between:  Body: portion of tongue that resides in oral cavity  Root: posterior third residing in oropharynx – Does not contain papillae, but still bumpy because of lingual tonsil, which lies deep to its mucosa

Answer 28

: congenital condition in which children are born with an extremely short lingual frenulum – Often referred to as “tongue-tied” or “fused tongue” – Restricted tongue movement distorts speech – Treatment: surgical snipping of frenulum

Answer 29

– Cleanses mouth – Dissolves food chemicals for taste – Moistens food; compacts into bolus – Begins breakdown of starch with enzyme amylase

Answer 30

are scattered throughout oral cavity; augment slightly.

Answer 31

parotid, submandibular, and sublingual?

Answer 32

anterior to ear and external to masseter muscle  Parotid duct opens into oral vestibule next to the second upper molar

Answer 33

medial to body of mandible  Duct opens at base of lingual frenulum

Answer 34

: anterior to submandibular gland under tongue  Opens via 10–12 ducts into floor of mouth

Answer 35

produce watery secretion, enzymes, ions, bit of mucin

Answer 36

produce mucus

Answer 37

dry mouth, uncomfortable condition caused by too little saliva being made

Answer 38

– Mostly water (97–99.5%), so hypo-osmotic – Slightly acidic (p H 6.75 to 7.00) – Electrolytes: N a+, K+, C l−, P O42−, H C O3− – Salivary amylase and lingual lipase – Proteins: mucin, lysozyme, and I g A – Metabolic wastes: urea and uric acid – Lysozyme, I g A, defensins, and nitric oxide from nitrates in food protect against microorganisms – 1500 m l/day can be produced – Minor glands continuously keep mouth moist

Answer 39

 Ingested food stimulates chemoreceptors and mechanoreceptors in mouth, sending signals to Salivatory nuclei: – Salivatory nuclei in brain stem that stimulate parasympathetic impulses along fibers in cranial nerves VII and IX to glands – Strong sympathetic stimulation inhibits salivation and results in dry mouth (xerostomia) – Smell/sight of food or upset G I can act as stimuli

Answer 40

* Teeth lie in sockets in gum-covered margins of mandible and maxilla

Answer 41

process of chewing that tears and grinds food into smaller fragments

Answer 42

– Primary dentition consists of 20 deciduous teeth, or milk or baby teeth, that erupt between 6 and 24 months of age – 32 deep-lying permanent teeth enlarge and develop while roots of milk teeth are resorbed from below, causing them to loosen and fall out  Occurs around 6–12 years of age – All but third molars (wisdom teeth) are in by the end of adolescence  Third molars may or may not emerge around 17–25 years of age

Answer 43

– Incisors: chisel shaped for cutting – Canines: fanglike teeth that tear or pierce – Premolars (bicuspids): broad crowns with rounded cusps used to grind or crush  Molars: broad crowns, rounded cusps: best grinders – During chewing, upper and lower molars lock together, creating tremendous crushing force

Answer 44

shorthand indicator of number and position of teeth – Shows ratio of upper to lower teeth for only half of mouth; other side is mirror image – Primary – Permanent

Answer 45

exposed part above gingiva (gum) – Covered by enamel, the hardest substance in body * Heavily mineralized with calcium salts and hydroxyapatite crystals * Enamel-producing cells degenerate when tooth erupts, so no healing if tooth decays or cracks; needs artificial repair by filling

Answer 46

portion embedded in jawbone – Connected to crown by neck – Canines, incisors, and premolars have only one root  First upper premolar often has two – First two upper molars have three roots – First two lower molars have two roots – Third molar roots vary; often single fused root

Answer 47

calcified connective tissue – Covers root; attaches it to periodontal ligament

Answer 48

– Forms fibrous joint called gomphosis – Anchors tooth in bony socket (alveolus)

Answer 49

: groove where gingiva borders tooth

Answer 50

bonelike material under enamel – Maintained by odontoblasts of pulp cavity

Answer 51

surrounded by dentin

Answer 52

connective tissue, blood vessels, and nerves

Answer 53

as pulp cavity extends to root

Answer 54

– Entry for blood vessels, nerves, etc.

Answer 55

a tooth that remains trapped in the jawbone * Can cause a good deal of pressure and pain * Wisdom teeth are most commonly involved. * Treatment: surgical removal

Answer 56

demineralization of enamel and dentin from bacterial action – Dental plaque (film of sugar, bacteria, and debris) adheres to teeth – Acid from bacteria dissolves calcium salts – Proteolytic enzymes digest organic matter – Prevention: daily flossing and brushing

Answer 57

– Plaque calcifies to form calculus (tartar) – Calculus disrupts seal between gingivae and teeth – Anaerobic bacteria infect gums – Infection is reversible if calculus removed

Answer 58

– Neglected gingivitis can escalate to disease – Immune cells attack not only bacterial intruders, but also body tissues  Can destroy periodontal ligament  Can activate osteoclasts, which leads to dissolving of bone and possible tooth loss – May increase heart disease and stroke two ways:  Promotes atherosclerotic plaque formation  Bacteria entering blood can cause clot formation in coronary and cerebral arteries – Risk factors: smoking, diabetes mellitus, oral piercings

digestive system Flashcards

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