Term
| mesentery: anatomical position |
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Definition
| peritoneal membrane that suspends the ileum and jejunum in loose folds from the posterior abdominal wall |
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Term
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Definition
1) to support blood vessels, nerves and lymphatics
2) facilitate intestinal motility |
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Term
| diameter and length of small intestine |
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Definition
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Term
| parts of the small intestine (order) |
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Definition
1) duodenum
2) jejunum
3) ileum |
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Term
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Definition
surrounds organs of the abdomen and pelvic cavity. A serous membrane.
-visceral: over organs
-parietal: lines abdominal cavity wall |
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Term
| 2 types of digestive movements: describe each |
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Definition
-peristalsis: progress food forward
-segmentation: backward and forward motion in digestive tract to allow mixing with digestive enzymes |
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Term
| describe muscle movement n peristalsis |
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Definition
circular muscles contract behind food, prevent backwards action.
In front of food, the circular mucles in front of food relaxes to allow a larger diameter and longitudinal muscles contract to shorten length |
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Term
| three pairs of salivary glands |
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Definition
1) left and right submandibular glands
2) left and right sublingual glands
3) left and right parotid glands |
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Term
| location of salivary gland control centre |
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Definition
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Term
| nervous system control of salivary glands |
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Definition
| parasympathetic nervous system |
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Term
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Definition
sensory: taste
mechanoreceptors: presence of objects
pressure receptors |
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Term
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Definition
| intrinsic nerves forming a network that controls digestive function |
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Term
| layers of enteric nervous system: location and role |
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Definition
1) submucosal plexus (meissner's plexus): submucosal layer . Controls small or localised functions
2) myenteric plexus: between layers of muscular is layer. Is a collection of neurone that controls larger regions of the digestive tract |
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Term
| role of sensory nerves in enteric nervous system |
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Definition
| local environment of digestive system can be sensed and relay afferent signals to the enteric nervous system. Nervous system can alter function accordingly to maintain appropriate environment |
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Term
| how enteric nervous system exerts control |
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Definition
| use of efferent signals (neurons to target cells) |
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Term
| autonomic nervous system controls: describe role in digestive system |
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Definition
parasympathetic: increase digestive functioning (secretions, motility increases and sphincter relaxation)
sympathetic: decrease digestive function |
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Term
| vagus nerves (cranial nerve X) |
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Definition
| innervates parasympathetic nervous system |
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Term
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Definition
| innervate sympathetic nervous system |
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Term
| organs that splanchnic blood flow provides blood to |
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Definition
oesophagus
stomach
small and large intestines
liver
gallbladder
spleen
pancreas |
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Term
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Definition
| when ileum becomes distended, the ileogastric reflex inhibits gastric motility and thus preventing more chyme entering the intestine ileum |
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Term
| intestinointestinal reflex |
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Definition
| when one part of the intestine becomes overdistended, the intestinointestinal reflex inhibits motility |
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Term
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Definition
| ileogastric and intestinonintesnal reflex control |
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Term
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Definition
stimulates
-increase of gastric motility and secretions
-increase ileal activity and motility
-relax ileocaceal sphinter (ileum -> caecum) , emties ileum and allow entry of more chyme |
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Term
| what happens when fasting and why |
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Definition
| the entire length of intestinal tract (stomach to terminal ileum) is swept with slow waves. This allows residual gastric and intestinal contents to be propelled into the colon |
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Term
| defecation reflex stimulation-how? |
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Definition
| movement of faeces into sigmoid colon and rectum will stimulate the defecation reflex |
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Term
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Definition
| rectal wall stretches and constricted internal anal sphincter constricts relaxes |
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Term
| control of anal sphincter contraction |
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Definition
| autonomic nervous system- smooth muscle |
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Term
| voluntarily override defecation urge- how and what happens? |
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Definition
how: contract external anal sphincter and muscle of the pelvic floor
effect: gradual relaxation of rectal wall. This reduces tension and urge may pass |
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Term
| retrograde contraction of rectum |
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Definition
| displaces faeces out of rectal vault until more convenient time |
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Term
| when does food become faeces |
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Definition
| by the time mass enters the sigmoid colon, all is waste |
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Term
| vitamins absorbed in large intestines |
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Definition
| vitamin B and K- produced by bacteria |
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Term
| where does absorption occur in large intestines |
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Definition
| caecum, ascending, transversing and descending colon |
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