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BIO202-CH23-Digestiv
BIO202 - Ch 23 - Digestive System - Marieb/Hoehn - RioSalado - AZ
Question | Answer |
---|---|
2 main groups of digestive system organs. | Alimentary canal & accessory digestive organs. |
Alimentary canal | GI tract (gut) - continuous, muscular digestive tube that digests & absorbs food. |
Organs of alimentary canal | Mouth, pharyx, esophagus, stomach, sm. intestine, & lg. intestine. |
Organs of accessory digestive organs. | Teeth, tongue, gallbladder, salivary glands, liver & pancreas |
Name the 6 essential activities of food processing by digestive system. | (1) indegestion, (2) propulsion, (3) mechanical digestion, (4) chemical digestion, (5) absorption, (6) defecation |
Segmentation | Rhythmic local constriction of intestines - mixes food w/digestive juices & increases efficiency of absorption. |
When is chemical digestion essentially complete? | In the small intestine. |
Major absorptive site in digestive system. | Small intestine - absorbed through mucosal cells by active/passive transport into blood of lymph. |
Digestive activity is provoked by __. | a range of mechanical & chemical stimuli |
Sensors (__) are located in walls of tract organs. | mechanoreceptors & chemoreceptors |
Short reflexes are mediates entirely by __. | local (enteric) plexuses (gut-brain) in response to GI tract stimuli. |
Long reflexes are initiated by stimuli __. | involving CNS centers & extrinsic autonomic nerves |
Smooth muscle activity inhibited by __. | VIP (vasoactive intestinal peptide) or nitric oxide. |
All ventral body cavities contain __. | serous membranes |
peritoneum | Serous membrane lining interior of abdominal cavity & covers abdominal organs. |
mesentery | Peritoneum that extends to digestive organs from body wall & carries blood vessels, lymphatics, nerves & stores fat. |
retroperitoneal organs | Pancreas & parts of lg. intestine that adhere to dorsal abdominal wall w/o mesentery. |
intraperitoneal/peritoneal organs | stomach & digestive organs that keep mesentery & remain in peritoneal cavity. |
peritonitis | Inflammation of peritoneum - leaks stomach juices or burst appendix & feces (bacteria). |
What arteries serve digestive organs & hepatic portal circulation? | Splanchnic circulation - hepatic, spleen, & L. gastric branches & mesenteric arteries. |
4 tunic layers of alimentary canal | Mucosa, submucosa, muscularis externa, & serosa. |
Mucosa (mucous membrane) | Innermost layer, (1) secretes mucus, digestive enzymes, & hormones, (2) absorbs & protects against infectious disease. |
Epithelium of mucosa | Simple columnar w/goblet cells - diffuse endocrine |
Which layer is responsible for segmentation & peristalsis? | Muscularis externa |
Serosa | Outermost layer of intraperitoneal organs - visceral peritoneum - areolar CT w/mesothelium |
__ organs have both serosa & adventitia. | Retroperitoneal |
In-house nerve supply of alimentary canal. | Enteric neurons - semi-autonomous |
Myenteric nerve plexus supplies? | Gi tract wall & controls its motility. |
__ nervous system has more neurons than entire spinal cord. | enteric |
Posterior of oral cavity is the __. | oropharynx |
Oral mucosa responds to injury by producing __. | defensins - antimicrobial peptides |
What rises reflexively to close off nasopharynx when we swallow? | soft palate |
Ankyloglossia | "Tongue-tied" - short lingual frenulum |
mumps | Inflammation of parotid glands (myxovirus). |
2 types of secretory cells in salivary glands. | Mucous & serous |
Serous cells produce? | Watery secretion containing enzymes, ions & mucin. |
Parotid glands contain only __. | serous cells |
Saliva is __. | hypo-osmotic - 97-99.5% water - pH 6.75 - 7, mucin, lysozyme, & IgA |
Lingual lipase | Fat-digesting enzyme |