Alimentary Controls Flashcards
what are the somatic (voluntary) nerves that control the alimentary system
sensory and motor
what are the autonomic (involuntary) nerves that control the alimentary system
sympathetic and parasympathetic
what hormones contribute to the alimentary system?
cholecystokinin, gastrin, gastric inhibitory peptide, secretin
where does gastrin come from and what does it do?
it comes from G cells and it stimulates parietal cells to increase secretion of hydrochloric acid
what does gastric inhibitory peptide do and where is it produced?
cause an increase in insulin secretion from pancreas and is produced in the duodenum
where is secretin produced and what does it do?
it is produced in the duodenum and it reduces gastric acid secretion and increases HCO3 from pancreas
what is secreted in the oral cavity?
saliva
what is the motility in the mouth and pharynx?
chewing and swallowing
which parts of the alimentary system is under somatic control?
mouth and recto-anal canal
which parts of the alimentary system is under autonomic control?
stomach, small intestine and large intestine
what nerves control taste (gustation)
CN VII (facial) and CN IX (glossopharnygeal)
what nerve controls smell (olfaction)
CN I (olfactory nerve)
what nerve controls chewing and the loading of periodontal ligaments?
CN V (trigeminal)
what is the biggest salivary stimuli?
chemical - the TASTE of food
what muscles are involved in chewing?
jaw, facial, tongue muscles
what type of control is chewing?
skeletal controlled by somatic nerves (voluntary)
what nerves control chewing?
CN V (trigeminal), VII (facial) and XII (hypoglossal)
what muscles are involved in swallowing?
jaw, tongue and pharyngeal muscles
what type of control is swallowing?
skeletal controlled by somatic nerves
what nerves control swallowing?
CN V (trigeminal), IX (glossopharyngeal), X (vagus), XII (hypoglossal)
what type of muscle is present in the oesophagus?
mix of skeletal and smooth muscle
what nerve controls the oesophagus?
CN X (vagus)
what does the stomach secrete?
gastric juice
what motility movements does the stomach undertake?
filling, relaxation, mixing, propulsive, peristalsis and emptying
what are the 3 phases of gastric activity
cephalic phase, gastric phase and intestinal phase
what are the 3 different parts of the cephalic phase?
mechanical (chewing), chemical (taste, smell) and psychic (visual, emotional)
what are the 2 parts of gastric phase
mechanical (distension) and chemical (food in stomach)
what are the 2 parts of the intestinal phase?
mechanical (distension) and chemical (acid, protein in duodenum)
where is the cephalic phase?
head
where is the gastric phase?
intra-gastric
where is the intestinal phase?
intestine
what is the cephalic phase controlled by?
nerves (long reflex)
what is the gastric phase controlled by?
nerves (long and short reflexes) and hormones (gastrin)
what is the intestinal phase controlled by?
nerves (long and short reflexes), hormones (GIP, secretin)
what does the small intestine secrete?
intestinal juice
what are the motility movements of the small intestine
mixing, villus movements, segmentation contractions and peristalsis
what controls the small intestine?
mainly local nerves (short reflexes) in response to intra-luminal stimuli
when and where is secretin released from
duodenum in response to acid
what does secretin do?
stimulates secretion of bicarbonate-rich pancreatic juice
what stimulates bicarbonate secretion in the cephalic phase
vagus nerve
what stimulates bicarbonate secretion in the gastric phase?
vagus nerve
what stimulates bicarbonate secretion in the intestinal phase?
secretin and CCK and VIP
what stimulates enzymes in the cephalic phase?
vagus nerve
what stimulates enzymes in the gastric phase
vagus nerve
what stimulates enzymes in the intestinal phase?
CCK and gastrin and GIP
when and where is CCK released?
from duodenum in response to fat and protein
what does CCK do?
stimulates secretion of enzyme-rich pancreatic juice
what stimulates the secretion of bile and how?
vagus nerve by the relaxation of sphincter of Oddi
what stimulates the secretion of bile in the intestinal phase?
CCK and secretin
what stimulates the secretion of bile in the gastric phase?
vagus nerve
what secretions come from the large intestine and rectum?
mucous and some water and electrolytes
what are the motility movements in the large intestine and rectum?
mixing, mass movements (super peristalsis), defaecation
what are mixing/segmentation movements controlled by?
long reflexes
how are long reflexes triggered/
by food entering the stomach
where does the stimulation of long reflexes effect?
intestines (increased motility)
where does the gastro-ileal reflex effect?
ileum (increased motility)
where does the gastro-colic reflex effect?
colon (increased motility)
what is the control in the large intestine and rectum?
mainly neural, ANS, vagus to splenic flexure
what controls the pelvic nerves
S2,3,4
what controls the anal canal
ANS control of internal anal sphincter, voluntary control of external sphincter, sacral somatic nerves
