Digestive System Flashcards
GI components of the pelvic cavity
Large intestine
Anus
GI components of the abdominal cavity
Stomach
Small intestines
GI components of the head and neck
Mouth
Pharynx
Esophagus
6 accessory digestive organs
Teeth Tongue Salivary glands Liver Gall bladder Pancreas
Propulsion
Voluntary and involuntary processes move food through alimentary canal
Peristalsis
Forward movement of food along GI tract
3 steps in peristalsis
Contraction of circular muscles behind bolus
Contraction of longitudinal muscles ahead of bolus
Contraction of circular layer forces bolus forward
Segmentation
Local shimmying on bolus to break it up and mix it with enzymes
Mechanical digestion
Physically prepares food– mixing with saliva and churning in stomach
Chemical digestion
Breaks down food into components with enzymes in the mouth and small intestine
Mechanoreceptors
Sense stretching of stomach wall and triggers churning
Chemoreceptors
Detects acidity, osmolarity and triggers enzyme release
3 reflexes initiated by recpetors
Stimulates secretions
Mixing of luminal content
Movement along alimentary canal
Absorption
Passage from lumen of GI tract into blood. Mostly at small intestine
2 components of the Enteric nervous system
Submucosal nerve plexus
Myenteric nerve plexus
Submucosal nerve plexus
Found in submucosa and controls segmentation. Regulates activity of glands and activates smooth muscle of mucosa
Myenteric nerve plexus
Found between the longitudinal and circular muscle layers of the muscularis externa and controls peristalsis
Mesentery
Double layer of peritoneum holds GI tract down and contains vascular and neural control, stores fat
Lumen
Opening in GI tract (tube)
Mucosa
Innermost lumen layer secretes mucus
Submucosa
Localized muscle layer in lumen, surrounds mucosa
Muscularis Externa
Inner circular layer, outer longitudinal layer, with a myenteric nerve plexus between
Serosa
Outermost lumen layer contributes to the mesentery
Parietal peritoneum
Walls of abdomen and under diaphragm
Visceral Peritoneum
Covers organs
Peritoneal Cavity
Potential space between parietal and visceral layers
Dorsal mesentery
Starts at the back wall and attaches to an organ
Ventral mesentery
Connects two organs, or an organ to the front wall
Retroperitoneal
Organs that stick to the posterior abdominal wall, vascular connection through mesentery
6 retroperitoneal structures
Most of pancreas Kidneys Adrenal glands Duodenum Part of large intestine Aorta and IVC
Lesser Omentum
Ventral mesentery from the lesser curvature of the stomach to the inferior border of the liver
Greater omentum
Dorsal mesentery connects greater curvature of the stomach to the posterior wall. Goes around the small intestine and transverse colon
Falciform ligament
Ventral mesentery attaches superior surface of liver to the anterior abdominal wall
3 branches of abdominal aorta supplying organs
Celiac trunk
Superior mesenteric artery
Inferior mesenteric artery
Gingivae
Gums
Labial frenulum
Connects teeth to gums
Lingual frenulum
Connects tongue to gums
Vestibule
Space between lips and teeth
Tongue
Interlacing bundles of skeletal muscle
Filiform papillae
Surface roughness of tongue manipulates food, smallest and most numerous
Circumvallate papillae
Large 10-12 at back of the tongue, contains taste buds, first sensations of amylase
Sulcus terminalis
Separates tongue into portions where different nerves innervate– 2/3 oral cavity (facial nerve), 1/3 oropharynx (hypoglossal) – covered by lingual tonsil
Intrinsic tongue muscle
Shapes tongue but does not change position
Extrinsic tongue muscle
Alters tongue position (protrusion, retraction, side-to-side)
Adult dental formula
2I, IC, 2PM, 3M x2= 32 teeth
Deciduous dental formula
2I, 1C, 2M
Root of tooth
Anchored to bony components of oral cavity
Dentin
Bulk of the tooth
Pulp cavity
Filled with loos connective tissue, vascular and nervous supply
Cementum
Calcified material for anchoring
Periodontal ligament
Extensions from tooth into bone
Gomphosis joint
Fibrous joint between periodontal ligament and cementum
Saliva
Solvent that digests starch– amylase
How much saliva do we produce a day?
1- 1.5 L
Salivary glands
3 pairs of extrinsic glands innervated by the parasympathetic NS
Buccal glands
Intrinsic salivary glands
Parotid glands
Exocrine gland anterior to ear, between masseter muscle and skin. Opens into vestibule near second upper molar
Which nerve innervates the parotid gland
9
Submandibular gland
Along medial aspect of body of the mandible and opens at base of lingual frenulum
Which nerve innervates the submandibular gland
7