4 main tunics of alimentary tract
Out->in
- Serosa/ adventitia
- Muscularis externa
- Submucosa
- Mucosa
Name 3 innermost layers of mucosa layer
- Muscularis mucosae
- Lamina propria
- Epithelium
2-3 muscles on muscularis externa
- Outer longitudinal fibres
- Inner circular fibres
3* Innermost oblique
Where is muscularis externa composed of skeletal muscle (voluntary)?
Mouth, pharynx, upper oesophagus, anus
2 nerve plexus and locations
- Submucosal (Meissner’s) plexus in submucosa
2. Myenteric (Aurbach’s) plexus in b/w 2 muscles in muscularis externa
What initiates defecation reflex?
- Distension/strectch of rectal wall by faeces
- parasympathetic stimulated => colon & rectum contract, internal sphincter relax
- Voluntary movements assist in expel faeces: relax external sphincter
- Ab. cavity pressure, bc inspiration, increases and ab. muscles contract
What organs do greater and lesser ommentum attach to?
Greater: greater curvature of stomach to transeverse colon
lesser: stomach & duodenum to liver
WHat organs do falciform ligament, mesntery, mesolon attach to?
Falciform lig: liver to abd. wall
mesentery: Small intestine to post ab. wall
mesocolon: LI to post abd. wall
diff b/w intrinsic & extrinsic muscles in tongue
int: muscles lie w/n tongue
ext: “ attach to bones of skull
name of hole in diaphgragm & why
oesophageal hiatus»_space; so oesophagus can pass through to get to stomach
secrettions of submucosa & why?
mucous»_space; lubricate passing food
Name the 3 salivary glands and what they secrete?
- Parotid: serous (watery)
- Submandibular: serous>mucus
- Sublingual: mucus
Describe pharyngeal reflex (swallowing reflex pt 1)
- swallowing centre in MO
- soft palate elevates
- upper oesophageal sphincter relaxes
- elevated pharynx opens oesophagus
- bolus pushed into oesophagus by pharyngeal constrictors
- epiglottis tips to cover larynx and larynx is elevated to prevent bolus going down it
Describe the esophageal reflex (swallowing reflex pt 2)
stretch of esophagus causes enteric NS to initiate perastalsis in muscles of esophagus
Describe the gastro-ileal reflex
when stomach is full, garstin (hormones) => release of ileocaecal valve => SI empties
Describe the gastro-colic reflex
chyme in stomach initiates mass movements of contents in transverse colon to move into rectum
Describe the duodeno-colic reflex
chyme in duodenum initiates mass movementsof contents in transverse colon to rectum
Describe the mastification reflex
descending pathways from cerebrum => conscious control when chewing
Define haustral churning/contractions (haustrations)
segmentation integrated by local reflexes (intrinsic/enteric plexus)
Define Mass movements (in large intestine)
Peristaltic waves initiated by gastro-colic & duodeno-colic reflex and integrated by enteric plexus
