digestive Flashcards
process of digestive system
ingestion, mechanical processing, digestion, secretion, absorption, compaction and excretion
peristalsis features
muscular layer of digestive tract
- triggered by hormones, chemicals and physical stimulation
*the process of peristalsis
- circular smooth muscles contracts behind bolus from a series of peristaltic waves
-contraction of longitudinal smooth muscle
*motility (segmentation)
-contraction of circular smooth m. before and after bolus
-material is churned and fragmented ( allows it to be mixed with digestive secretions)
-triggered by hormones, chemical and physical stimulation
peritoneum
-simple squamous and deep to is lose CT
*serous membrane that surrounds some of the abdominal digestive organs (parietal, visceral and peritoneal)
* mesenteries
-double layer of peritoneum that suspends some organs
-contains blood and lymphatic vessels and nerves
*intraperitoneal vs retroperitoneal organs
intra: covered by the visceral peritoneum and suspended by mesenteries (stomach, liver, uterus)
retro: outside of peritoneal cavity, between posterior layer of parietal peritoneum and the back (esophagus, rectum, pancreas and kidney)
serosa
-most superficial layer of peritoneum
-surrounds intraperitoneal organs
-simple squamous epithelium
adventitia
-fibrous CT layer (lots of collagen)
-anchors retroperitoneal organs
muscular layer
smooth muscle and mechincally processes and propels materials
submucosa
layer of areolar CT (lose CT) deep to mucosa
-blood vessels, nerves and lymphatic vessels are found here too
mucosa
-deepest layer of digestive tract
-primary site of secretion and absorption
-mucus membrane
salivary gland
saliva: serous and mucus secretions (salivary amylase and other enzymes)
3 glands: parotid, submandibular, sublingual
innervated by autonomic nervous system
*functions of stomach
storage, mechanical and chemical digestion
*secretory cells of stomach (mucous surface and neck)
mucous surface cells (simple columnar): secretes mucus- protects deeper layer of stomach from acid environment
mucous neck cells- secretes water soluble fluid that lubricates stomach content (bolus)
*secretory cells of the stomach (parietal, chief and enteroendocrine)
parietal- secretes hydrochloric acid intrinsic factor
chief- secrete pepsinogen (activated by HCl)
enteroendocrine- secretes gastrin, stimulates parietal and chief