Lecture 19 - Digestive System 1 Flashcards
1
Q
what is the alimentary canal?
A
- aka gastrointestinal (GI) tract
- the tube through our body going from the mouth to the anus
2
Q
what are the organs of the alimentary canal?
A
- mouth
- pharynx
- esophagus
- stomach
- small intestine
- large intestine
- anus
3
Q
2 divisions of the digestive system
A
- alimentary canal
- accessory digestive organs
4
Q
what are the accessory digestive organs?
A
- teeth and tongue
- gallbladder
- salivary glands
- liver
- pancreas
5
Q
what is the role of accessory digestive organs?
A
to secrete salvia, bile and digestive enzymes to break down food
6
Q
what is helicobacter pylori?
A
- a bacteria that attacks the lining that protects your stomach and causes a hole in the wall of the alimentary canal
- people die because they bleed out due to arteries in stomach being digested
- causes gastritis and peptic ulcer disease
7
Q
peptic ulcers
A
an open sore or raw area in the lining of the stomach or intestine
8
Q
what are the 9 regions of the abdominal wall?
A
- R/L hypochondriac
- epigastric
- R/L lumbar
- umbilical
- R/L iliac (inguinal)
- hypogastric region
9
Q
what is in the right hypochondriac region?
A
- liver
- gallbladder
10
Q
what is in the epigastric region?
A
- stomach
11
Q
what is in right lumbar region?
A
- ascending colon of large intestine
12
Q
what is in the umbilical region?
A
- small intestine
- transverse colon of large intestine
13
Q
what is in the left lumbar region?
A
- descending colon of large intestine
14
Q
what is in the right iliac region?
A
- cecum
- appendix
15
Q
what is in the hypogastric region?
A
- urinary bladder
16
Q
what is in the left iliac region?
A
- initial part of sigmoid colon
17
Q
what is mesentery?
A
- double layer of peritoneum (a sheet of two fused serious membranes together)
- ends from the body wall to the digestive organs
18
Q
what are the two mesentery?
A
- ventral mesentery
- dorsal mesentery
19
Q
what is the visceral perotineum?
A
covers the external surfaces of most digestive organs
20
Q
what is the parietal peritoneum?
A
lines the body wall and is continuous with the visceral peritoneum
21
Q
what is the peritoneal cavity?
A
- potential space between visceral and parietal peritoneum
- lies between digestive organs abdominal body wall
22
Q
what are the components of the ventral mesentery?
A
- falciform ligament
- lesser omentum
23
Q
what are the components of the dorsal mesentery?
A
- transverse mesocolon
- greater omentum
- mesentery
- sigmoid mesocolon
24
Q
what are the 6 activities of the GI tract?
A
- ingestion
- propulsion (peristalsis)
- mechanical breakdown (segmentation)
- digestion
- absorption
- defacation
25
ingestion
process of taking in of food through the mouth/oral cavity
26
propulsion
movement of food through the alimentary canal via swallowing (voluntary) and peristalsis (involuntary)
27
what is peristalsis?
contraction and relaxation of muscle (muscularis externa) in organ walls to squeeze food down the canal
28
what is segmentation?
when non adjacent segments of the alimentary canal alternate contraction and relaxation moving food forward and backward = mixing of food + propulsion
29
mechanical breakdown
- physical preparation of food for digestion by enzymes breaking it down
- achieved by chewing, churning in stomach and segmentation
30
digestion
series of steps where food molecules are broken down into their chemical building blocks and secreted into lumen
31
absorption
transport of digested end products from lumen enter the blood and lymphatic capillaries
32
defacation
elimination of indigestible substances from the body as feces
33
what are the four layers of the alimentary canal?
- mucosa
- submucosa
- muscularis externa
- serosa
34
what are the 3 sublayers of mucosa?
1. epithelium
2. lamina propia
3. muscularis muscosae
35
what are the two layers of muscularis externa?
two layers of smooth muscle:
- circular layer
- longitudinal layer
36
what is the oral vestibule?
anything in the small slit-like space between the teeth and inner mucosal lining of the lips
37
what is the oral cavity proper?
is the region of the mouth that lies internal to the teeth
38
importance of uvula
helps prevent things from going up through the nasal cavity
39
what is the enteric nervous system?
- "the brain in the gut"
- helps facilitate the muscular and secretory functions of the gastrointestinal tract.
40
what is the myenteric nerve plexus?
- located in the muscularis externa between circular and longitudinal layers
- helps control peristalsis and segmentation
41
what is the submucosal nerve plexus?
- lies in the submucosa
- signal glands in the mucosa to secrete and to contract muscularis mucosae
42
what are the different teeth?
- milk
- deciduous
- permanent
- incisors
- canine
- eyetooth
- bicuspids
- molars
43
what are the salivary glands?
- parotid gland
- submandibular gland
- sublingual gland
44
what is mastication?
the act of chewing food
45
what are villi?
- the fingerlike projections of the mucosa which absorb digested nutrients
- help increase surface area
46
what are microvilli?
- even smaller finger-like projections on the villli
47
what are gastric pits?
indentations in the stomach which are entrances to the gastric glands
48
what are gastric glands?
branched tubules in the inner lining of the stomach that secrete gastric juice and protective mucus
49
what are the 3 main type of cells in the stomach?
- chief cell
- parietal cell
- enteroendocrine cell
50
what are chief cells
- secrete digestive enzymes that break food into smaller pieces
- example = pepsinogen
51
what are parietal cells
- cells in the stomach that secrete hydrochloric acid (HCl)
52
what are enteroendocrine cells
- specialized cells found that produce and release hormones in response to stimuli (i.e pepsin for pepsinogen)
53
what are goblet cells
- cells that serve as the primary site for nutrient digestion and mucosal absorption
54
what are mucous neck cells
- secrete mucous on the inside of the stomach
55
what is intestinal flora?
microorganisms, predominantly bacteria, that populate our intestines
