Physiology Flashcards
(138 cards)
1
Q
How many parts are there to the GI tract?
A
3: upper, middle, lower
2
Q
What makes up the upper portion of the GI tract?
A
Mouth Esophagus Stomach
3
Q
What makes up the middle portion of the GI tract?
A
Small intestine ( duodenum, jejunum, ileum)
4
Q
Where most digestive and absorptive processes occur..
A
Middle portion of GI tract (small intestine)
5
Q
Salivary glands
Liver
Pancrea
A
Accessory organs
produce secretions that aid in digestion
6
Q
Digestive enzymes produced by ______ _______ help breakdown food
*enzymes for initial digestion of LIPIDS and STARCHES
A
Salivary glands
(in mouth)
7
Q
Conduit for passage of food from pharynx to stomach
A
Esophagus
8
Q
Smooth Muscle
Mucosal glands
Submucosal glands
Pharyngoesophageal sphincter
Gastroesophageal spincter
A
Structures in the esophagus
9
Q
Provides peristaltic movements needed to move food
A
Smooth muscle of esophagus
10
Q
Secrete mucus to protect its surface and aid in food lubrication
A
Mucosal and submucosal glands
11
Q
Circular layer of striated muscle
Keeps air from entering esophagus and stomach during breathing
Prevents backup into trachea
A
Pharyngoesophageal spincter
12
Q
Circular muscle remains tonically contracted
Prevents backup into esophagus
Zone of high pressure that prevents reflux of gastric contents into esophagus
Relaxation during swallowing, allowing easy propulsion of esophageal contents into stomach
A
Gastroesophageal spincter
13
Q
Function= storage reservoir
*made up of= fundus, body, pyloric region, pyloric sphincter
A
Stomach
14
Q
Prevents regurgitation (from duodenum)
Keeps one-way passage
Helps control rate of emptying
A
Pyloric sphincter
15
Q
22 cm (10 in) long
Contains opening for the COMMON BILE DUCT and MAIN PANCREATIC DUCT
A
Duodenum
16
Q
A
17
Q
A fluid synthesized by the liver that breaks down lipids
A
Bile
18
Q
Facilitates digestion of:
lipids
carbohydrates
proteins
A
Pancreatic juices
19
Q
Food is digested and absored in the…..
A
Jejunum and ileum
20
Q
1.5 m (5 ft)
Divided into: cecum, colon, recutm and anal canal
A
Large intestine
21
Q
Blind pouch that projects down at the junction of the ileum and colon
A
Cecum
22
Q
Lies at the upper border of the cecum
Prevents the return of feces from the cecum into the small intestines
A
Ileocecal valve
23
Q
Mostly for water reabsorption
storage channel, waste, elimination
A
Large intestine
24
Q
Mucosal layer
Submucosal layer
Muscularis externa
Serosal layer
A
4 layers of gastrointestinal wall
25
Made up of:
Epithelum lining (single layer of cells)
Laminar propriae (loose connective tissue)
Muscularis mucosa (smooth muscle)
**Inner mucosal layer** of GI wall (aka **mucosa**)
26
Where are microvilli (fingerlike projections that increase surface are) found?
In the **lamina propria of the mucosa**
27
1. production of mucus that protects and lubricates inner linning
2. secretion of digestion enzymes that break food down
3. absorption of the breakdown products of digestion
4. maintence of a barrier
**_Function_ of mucosal layer** of GI tract
28
Lymphatics within the mucosa serves as the body's....
29
Helps with lubrication
Dense connective tissue
Veins, arteries, nerves- **responsible for secreting digestive enzymes**
Submucosal layer of GI
30
made up of 2 concentric and thick layers of smooth muscle:
inner (circularly arranged)
outer (longitudinally arranged)
**in between the 2 layers= connective tissue layer with nerves (control smooth muscles, blood, lymph)**
**\*\*FACILITATES MOVEMENT OF GI TRACT**
Muscular externa
31
Serous membrane with a layer of squamous epithelium (mesothelium)
Small amount of underlying connective tissue
**most superficial layer**
Serosa (mesothelium)
32
Encloses portion of abdominal viscera
Attaches to abdominal wall
Contains: blood and lymphatic vessels
Holds organs in places
Stores fat
Mesentary double layer
33
Double layered extension or fold of peritoneum that passes from the stomach or proximal part of the duodenum to adjacent organs in the abdominal cavity
Omentum
34
Extends from stomach to transverese colon and intestinal folds
Contains fat
Mobile and moves with peristalsis
Often forms adhesions adjacent to inflamed organs, **which prevents spread of infection**
Curshions organs against injury (provides insulation)
Greater omentum
35
Extends between transverse fissure of the liver to the lesser curvature of the stomach
Lesser omentum
36
Intermittent contractions that mix and move things along
Found in the **esophagus, antrum, small intestine**
**Rhythmic** motility
37
Movement found in sphincters
Strong muscle bands that prevent movement in wrong direction
**Constant contraction without relaxation periods**
Found in: **lower esophagus, upper stomach, iliocecal valve, internal anal sphincters**
**Tonic** motility
38
Cells are electrically coupled by low resistance pathways
Allow electrical initiation to muscle contractions
Gap junctions where messages are passed quickly and readily
Large bundles of fiber
**Unitary** cells
39
Create **SLOW** waves- rhythmic, spontaneous oscillations in membrane potentials
Range= 3-12 minutes
Generated by thin layer of interstitial cells
Bring closer to threshhold potential
**Pacemaker** cells
40
The GIs own nervous system
\*lies entirely within the wall of the GI tract
composed of 2 plexuses:
- Outer myenteric (Aurebach)
- Innter submucosal (Meissner)
Enteric nervous system
41
Which enteric nervous system plexus...
Located **between cells**
Linear chain of interconnecting neurons
\***concerned maily with motility along the length of the gut**
Myenteric plexus
42
Which enteric nervous system plexus....
Lies between submucosal and mucosal layers
Responsible for: **local control of motility, intestinal secretions, absorption of nutrients**
**\***integrates signals from muscle layer and lumen, stretch receptors
Submucosal Plexus
43
Monitor the stretch and distention of the GI tract wall
Mechanoreceptors
44
Monitor the chemical composition
- Osmolality
- pH
- Digestive products of protein
- Fat metabolism
Chemoreceptors
45
These cells do not create APs or initiate muscle contraction
\*just bring it closer to potential
**Slow waves of membrane oscillations**
(no calcium channels)
Pacemaker cells
46
Parasympathetic NS innervates the GI system mostly through....
Vagus nerve
47
Thoracic chain of ganglia
Celiac
Superiror mesenteric ganglia
Inferior mesenteric ganglia
Sympathetic innervation of the GI system
48
Starts voluntary
Becomes involuntary
**becomes involuntary as food or fluid reaches the pharynx**
Swallowing
49
Trigeminal N.
Glossopharyngeal N.
Vagus N.
Hypoglossal N
Innervation of oral and pharyngeal phase
50
Vagus N. is the innervation of which phase?
Esophageal phase
51
Bolus collected in back of mouth
Get into position/ ready to be pushed backwards
**Oral (voluntary)** phase of swallowing
52
Soft palate pulls upward to **close off nasopharynx to prevent regurgitation**
Vocal folds close off trachea
Reflexes push things down into esophagus
**Pharyngeal (involuntary)** phase
53
Primary peristalsis (voluntery, upper 1/3 with striated muscle)
Secondary peristalsis (involuntary, lower 2/3 smooth muscle)
**Esophageal phase** of swallowing
54
Pressure in the lower esophageal sphincter is normally _____ than pressure in the stomach
**prevents reflex of gastric contents**
GREATER!
55
How does bolus get past the gastroesphageal spincter into stomach?
**Stretch receptors** sense the bolus and tell sphincter to relax
56
CNS lesions (ie stroke)
Narrowing of esophagus (stenosis)
Muscle weakness
Functional obstruction
Lack of salivation
...can cause?
Dysphagia
(dysphagia= **symptom, NOT a diagnosis)**
57
"Failure to relax"
Problem with **lower esophageal sphincter**
**birds beak\*\* is pathognomonic**
primarily an issue with innervation
Achalasia
(glucagon can help relax sphincter)
58
Glucagon
Nitro
Metoclopramide
...can be used to?
Help pass bolus of food
**these will relax muscle/sphincter**, allowing food to pass thru into stomach
59
Seen in **alcoholics**
due to excessive vomit (often **vomit blood**)
Due to **mucosal tears at the gastroesophageal junction**
~10% of upper GI bleeds
Mallory-Weiss Syndrome
60
Midsternal pain, discomfort.."heart burn"
due to problem with lower esophageal sphincter
**worse with acidic foods and lying down**
GERD
61
Does GERD pain correlate with extent of mucosal injury?
NOPE.
62
Often ER treats with...
"GI cocktail": Benadryl, lidocaine, malox
What is this for?
Acute GERD tx
63
Where are columnar cells **normally** found?
Intestines (where there is acid)
\*excess acid in esophagus leads to change (squamous --\> columnar..**Barrett's esophagus**)
64
The most potent signals for gastric motility come from....
Enteric nervous system
65
Abnormally thick muscularis layer in the terminal pylorus
\*vomitting
\***olive/grape shaped mass on abdominal exam, vomitting child**
Hypertrophic pyloric stenosis
66
Decreased gastric muscle tone
Complication of **visceral neuropathies** (ie diabetes)
Can also be due to...surgical procedures that disrupt vagal activity
Gastric atony
67
Obstructions (scar tissues, ulcers)
Gastric atony
Hypetrophic pyloric stenosis
All do what to the rate of digestion?
**SLOWS rate!**
\*gastric retention
68
What is the syndrome when digestion rate is **too fast?**
Dumping syndrome
69
Complication of gastric surgeries
Rapid dumping of hydroacidid and hyperosmotic gatric secretions
Diarrhea, abdominal cramping
Dumping syndrome
70
Slow contractions of the circular muscle layer
Contents moving forward and backward
**Mixing the chyme with digestive enzymes from pancreas to make sure enough chyme is expose to mucosal surface area**
\*frequency increases after meals
\*stimulated by receptors in stomach and intestine
Segmentation waves
71
Rhythmic propulsive movements that **propel chyme toward large intestine**
Sequential relaxation
Ileocecal valve
72
Peristaltic movements are influenced by which plexus?
Myentertic plexus
73
**Inflammation**..can cause hyper or hypo motility
**ileus** (impairment of intestinal motility), especially post op
\*\*delayed passage of chime
| (hypermotility can lead to diarrhea..getting rid of infection)
Problems with **small intestine motility**
74
impairment of intestinal motility, especially can after post op
Ileus
75
Two types of movement seen in large intesine
1. segmental
2. propulsive
76
Haustrations
Local digging- type action
Ensures all portions of fecal mass are exposed to the intestinal surface
Segmental movement (in lg intestine)
77
Large segment contracts as a unit
Timing!..mass movement lasts about 30 seconds
Relaxation periods= 2-3 minutes
Then another mass movement
Propulsive movement (large intestine)
78
Circular, **involuntary** smooth muscle
Internal anal sphincter
79
Striated, **voluntary** muscle
Innervated by the **pudendal nerve**
External anal sphincter
80
Which reflex....
Controlled by **enteric nervous system**
\*Initiated by distention of the rectal wall with initiation of reflex peristaltic waves that spread through the descending colon, sigmoid colon and rectum
Intrinsic myenteric reflex
81
Which reflex....
Integrated at level of sacral cord
When the nerve endings in the rectum are stimulated, signals are transmitted to the sacral cord and then reflexively back to the descending colon, sigmoid colon, rectum, anus and pelvic nerves
**Increase peristaltic movements and relax the internal sphincter**
Parasympathetic reflex
82
Large volume, watery, non bloody
cramps, bloating, N/V, dehydration, hypokalemia
caused by: staph, E. coli, giardia, cholera, etc.
Noninflammatory diarrhea
83
Projective vomit shortly after eating
..what is usually the cause?
Staph aureus
84
Small volume, fever, bloody
usually affects the colon itself more (reason for smaller volume)
lower abdominal pain, urge to defecate comes on quick!
caused by: invasion (shigella) or toxin (c.diff)
Inflammatory diarrhea
85
Length of acute vs. chronic diarrhea?
Acute..1-2 weeks
Chronic..longer than 3-4 weeks
86
Transit time interferes with absorption
\***water is being pulled into bowel**
ie..lactose intolerance
if pt cannot digest lactose, it is undigested in lumen..which draws water into bowel and leads to diarrhea\*
Osmotic diarrhea (chronic)
87
Osmotic
Secretory
Inflammatory
Parasitic
Factitious
Causes of chronic diarrhea
88
Pain, incontinence sometimes
frequency and urgency!
Colicky abdominal pain
ie..Chron's, ulcerative colitis
Inflammatory diarrhea (chronic)
89
Excessive laxative use can cause what type of chronic diarrhea?
Factitious
90
Viral cause of diarrhea
\*seen in kids mostly
\*very **virulent!** dont need much of virus to get sick
big concern= dehydration
\*vaccine against now
Rotavirus
91
S. aureus
Shigella
Salmonella
Campylobacter
**C diff**
**E. Coli**
Bacterial causes of diarrhea
92
Severe, life threatening complication of C.dif
**toxins ruined membrane lining**
Pseudomembranous colitis
93
What happens to WBC count in c diff?
HIGH!!!!
94
Shigella like toxin..gets into mucosal lining
**bloody diarrhea**
Can get into bloodstream...Hemolytic Uremic Syndrome
(hemolytic anema, thrombocytopenia, etc)
E Coli
95
Tx for E. coli?
Nothing..let the body treat itself/flush it out
Tx symptomatically
**NO ANTIBIOTICS!!..will worsen**
96
Persistent/recurrent sxs of abominal pain
Alter between diarrhea/constipation
Flatulence, bloating, nausea, anorexia
**HALLMARK= abdominal pain relieved by defecation\*\*\*\***
Irritable bowel **syndrome**
97
Axial arthritis affecting spine, SI joints
\*uveitis
Skin lesons- erythema nodosum
Stomatitis
Anemia
Hypercoagulability
Inflammation of bile duct
Inflammatory bile disease
98
Can occur anywhere, but most common in distal colon
**Skip Lesions in submucosa**
```
Intermittent diarrhea (usually not bloody), colicky pain
weight loss, ulceration of perianal skin
```
**bowel wall thickens overtime, rigid. "led pipe"**
long term..can cause fistulas (which may make prone to bacterial infections)
Chron's disease
99
**Bloody diarrhea**, mucousy diarrhea
starts in rectum, moves proximally
nocturnal diarrhea, weakness, fatigue, thickened bowel wall
**crypt abscesses**\*...HEMORRHAGES! psuedopolyps
complications= **toxic megacolon, colon cancer**
Ulcerative colitis
100
Think what when you hear **crypt abscesses**
Ulcerative colitis
101
Pseudo vs true diverticula
Psuedo= only musoca and sub muscoa involved
True= all layers!
102
Presence of diverticula
May be asymptomatic
Diverticul**osis**
103
Inflammation and perforation of diverticula
LLQ pain
first line tx usually "bowel rest"...dont eat much. clear fluids
if abscess forms...may eventually need antibiotics
Diverticu**litis**
104
105
Perforation with peritonitis
Hemorrhage
Bowel obstruction
Fistula
Possible diverticulitis complications
106
Can be normal-transit (nothing wrong..just slowed down)
Can be slow-transit (innervation issue like Hirschsprung dz, which is a lack of ganglion cells/innervatin in the bowl)
Constipation
107
New onset of constipation in elderly, might want to check what levels?
Thyroid (could be hypothyroid issue)
108
Disease where there are no ganglion cells in bowel
\*can lead to constipation (slow-transit)
Hirschsprung disease
109
Sx: pain, distention, vomitting
can be **mechanical** cause: hernia, adhesions, intussesception, volvulus
can be **paralytic** cause
Obstruction
110
"telescoping bowel"
MC abdominal emergency affecting children under 2
Intermittent symptoms
Tx and dx with=contrast, enema
Intussesception
111
Twisting of bowel on own axis
can lead to obstruction
Volvulus
112
If the obstruction is paralytic, are there bowel sounds?
NO
113
Largest endocrine organ in the body
GI tract
114
G cells in antrum of the stomach, duodenum
Stimulated by vagus nerve
Secretion inhibited by acid content of stomach antrum (pH under 2.5)
Gastrin
115
Stimulates secretion of growth hormone
Acts as appetite stimulating signal from stomach when an increase in metabolic efficacy is necessry
Ghrelin
116
Action= stimulates secretions of gastric acid and pepsinogen
Increases gastric blood flow
Stimulates gastric smooth muscle contraction
Stimulates growth of gastric acid and intestinal mucosal cells
Gastrin
117
118
Important mediator for appetite and meal size control
Made by **I cells in intestinal mucosa**
Cholecystokinin (CCK)
119
1. Mucus: lubricate and protect mucosal layer
2. Digestive and asborption: secretion of enzymes to aid
2 functions of GI secretions
120
50-200 ml leaves body in stool
Mostly.....
water and some Na, K
121
Which part of ANS **increases** secretory activity?
Parasympathetic
122
1. protection and lubrication
2. antimicrobial (**lysozyme)**
3. digestion **(ptyalin and amylase)**
Functions of salivary secretions
123
- Gastric acid
- Intrinsic factors
..produced by what cells?
Parietal cells
124
- Pepsin
- Gastric lipase
...made by what cells?
Chief cells
125
Gastrin
..producd by what cells?
G cells
126
Molecules that:
break down prostaglandins
are lipid soluble
**ie...NSAIDs, aspirin, ETOH, bile salts, etc.**
Can damage gastric mucosa!
127
Improve bloodflow to mucosal lining
Decrease acid secretion
Increase mucus production
**overall...protects mucosal lining**
Prostaglandins
128
Tight junction of cells
Covered with hydrophobic lipid layer
Equal secretion of H and HCO3
Ways the gastric lining protects itself
129
Secretes HCl
Intrinsic factor (necessary for absorption of vitamin B12)
Parietal cells
130
Gastrin
Ach
Histamine
...all stimulate?
Gastric acid
131
Cephalic (start thinking about food, salivating)
Gastric (HCl starts to get secreted)
Intestinal (Secretin suppresses gastric function)
3 phases of gastric acid stimulation
132
Primary location affected by peptic ulcer disease?
Duodenum
133
Gastrinoma (gastrin secreting tumor)
Diarrhea (bc more gastrin, changing osmotic gradient.secretory diarrhea)
\*over 2/3 are malignant
generally diagnosed late!
Zollinger-Ellison Syndrome
134
135
Concentrated at site where contents from stomach and secetions
from liver and pancreas enter duodenum
Secrete large amounts of **alkaline mucus** that protects duodenum from acid content
Brunner glands
136
Starch (50%)
Sucrose (30%)
Lactose (6%)
Maltose (1.5%)
Carbohydrates we digest/absorb
(need to be broken donw into **monosaccharides** before they can be absorbed)
137
138
Breakdown of large dietary fat globules
Increases number of triglycerides
