Week 7 - Digestive System Flashcards
(47 cards)
What is the difference between peristalsis and segmentation?
- Peristalsis involves the contraction of longitudinal muscles
- Segmentation involves the contraction of circular muscles
Why is the oral cavity line with stratified squamous epithelium?
Allows it to withstand friction and abrasion of eating
How do the lips and cheeks aid in the mastication of food?
Help keep food in between the teeth as we chew
Differentiate between the hard and soft palate of the mouth
- Hard palate - forms a hard surface which food can be forced against when chewing.
- Soft palate - closes of the nasal passages during swallowing
What accessory organ of the mouth is used in the process of mastication?
Teeth
What is bolus?
Is the mixture of food and saliva that forms during chewing
What kind of muscle is the tongue made of?
Skeletal muscle
What are the 2 functions of the tongue?
- Speech
* Taste
What role does saliva play in the digestive processes of the mouth?
- Contains enzymes that begin the break down of starch
- Helps moisten food and create bolus
- Cleanses the mouth
What two regions of the pharynx are involved in digestive system activity?
- Nasopharynx - N/A
- Oropharynx
- Laryngopharynx
What are the 4 steps associated with digestion in the mouth?
1) ingestion
2) chemical digestion - amylase
3) mechanical digestion - teeth
4) swallowing of food into the pharynx
What are the two phases associated with swallowing?
- Buccal - voluntarily pushing food into pharynx
* Pharyngeal / oesophageal - involuntarily swallowing of food into the oesophagus.
Describe the basic function of the stomach
- Intake of food from the oesophagus
- Temporary storage of food
- Digestion of food via enzymes and mechanical digestion
- Moves chyme into the duodenum
What separates the stomach from the duodenum?
Pyloric sphincter
What cells make up the gastric glands? What are their functions?
- Parietal cells - Secrete HCl
- Mucous neck cells - unkown
- Chief cells - secrete lipases
- Enteroendocrine cells - secrete hormones that aid in digestion
Name the three phases of gastric secretion
- Cephalic phase
- Gastric phase
- Intestinal phase
What is the stimulus for the cephalic phase of gastric secretion?
• Sight, taste, thought or smell of food
What is the purpose of the cephalic phase of gatric secretion?
To prepare the stomach for the arrival of the bolus
What initiates the gastric phase of gastric secretion?
Neural and hormonal stimuli that occurs once the food has entered the stomach
What initiates the intestinal phase of gastric secretion?
The low pH of the duodenum as chyme enters small intestines
What is chyme?
Is the fluid that passes form the stomach into the small intestines, consisting of gastric juices and partially digested food
What is the purpose of the intestinal phase of gatric secretion?
To secrete more gastric to have a brief effect and then to inhibit the secretion of gastric juices.
What are the three different contractile activities of the stomach? Exlpain
- Propulsion -peristaltic contraction that move contents towards the pylorus
- Grinding - Mixing of the stomach contents
- Retropulsion - Delivers small amount of chyme into the duodenum.
What is the role of the liver in the digestive system?
The liver produces bile
