progress test #2 Flashcards
1
Q
what four things make up the upper respiratory system?
A
nose, nasal cavity, paranasal sinuses pharynx
2
Q
what type of epithelium does the conducting region have?
A
respiratory epithelium
pseudostratified ciliated columnar epithelium (with goblet cells)
3
Q
what type of epithelium is at the site of olfaction?
A
olfactory mucuosa.
4
Q
what type of passage is the nasopharynx
what 3 parts are in this region
A
air only passage (respiratory epithelium)
soft palate and uvula- block nasopharynx during swallowing
auditory tubes from middle ear drain here
pharyngeal tonsils- on posterior wall
5
Q
what type of passage is the oropharynx
what type of epithelium does it have and what type of tonsils does it have?
A
air and food passage- has stratified squamous for protection against abrasion
lingual and palatine tonsils
6
Q
what type of passage is the laryngopharynx, what type of epithelium and where does it extend from?
A
air and food- has stratified squamous epithelium for protection against abrasion
from the hyoid bone to the larynx/ beginning of esophagus
7
Q
what type of epithelia does the stomach, small and large intestine have?
A
simple columnar for secretion/ absorption
8
Q
what are the four layers of the gut tube, innermost to outermost
A
mucosa
submucosa
muscularis
adventitia
9
Q
what is the muscularis mucosae
A
a layer of smooth muscle that lies in the mucosal layer
controls tiny localised movements
10
Q
what is the submucosal nerve plexus
A
collection of nerves in the submucosa that regulates secretion
11
Q
what are the two main layers of the muscularis layer?
A
musclaris consists of smooth muscle
-inner circular
-outer longitudinal
12
Q
what do parotid salivary glands secrete?
A
serous fluid with amalyse
13
Q
what do sublingual salivary glands secrete?
A
mucus only
14
Q
what do submandibular salivary glands secrete?
A
both serous fluid and mucus.
15
Q
what do duct cells secrete?
A
bicarbonate (PH buffer)
16
Q
how does the muscularis externa layer alter as it moves down the esophagus?
A
first 1/3- skeletal muscle
middle 1/3 a mixture
last 1/3- smooth muscle
17
Q
how does the esophagus get lots of mucus for lubrication and protection?
A
Doesnt have goblet cells, it has glands with ducts to the surface in both the mucosa and submucosa
18
Q
what is the peritoneum?
A
the serous membrane that lines the abdomen, has a parietal and a visceral layer and between these layers if a fluid filled space.
19
Q
what does the lesser omentum connect together?
A
The liver and the stomach
20
Q
what does the greater omentume connect together?
A
attatches the stomach to the transverse colon
21
Q
how is the muscularis layer in the stomach modifed?
A
It has three layers rather than two,
oblique- inner
circular- middle
longitudinal- outer
these three different ways of movement allows for food to be churned up.
22
Q
how is the submucosa layer in the stomach modified?
A
has rugae, temporary folds allowing for expansion of stomach.
submucosa is the core of the rugae
23
Q
how is the mucosa layer modified in the stomach?
A
has simple columnar epithelium
has in-folding with increases the surface area for secretions, gastric glands which are always there
24
Q
what do G cells secrete
A
hormones- gastrin
25
what do pareital cells secrete?
what organelle do they have a lot of ?
and what is a factor or their structure?
acid and intrinsic factor
have a lot of mitochondria
have a folded structure to increase surface area
26
what do chief cells secrete,
what organelle do they have a lot of
what do they contain
pepsinogen
a pepsin pre cursor.
they contain a lot of rough endoplasmic reticulum and they contain apical zygomen granules (vesicles that get the enzymes out of the cell)
27
what are the exocrine features of the pancreas?
has acinar cells that secrete digestive enzymes
duct cells secrete bicarbonate
28
what two cell types are simular with charactaristics such as containing apical zygomen granules, having a basal nucleus and lots of rough ER
pancreatic acinar cells and chief cells
29
how do secretions enter the small intestine from the pancreas
secretions enter the hepatopancreatic ampulla. Then the hepatopancreatic sphincter controls when enzymes and secretions get into the duodenum.
30
what are the three sections of the small intestine and indicate which is the smallest and largest
duodenum (first and smallest)
jejunum
illeum (longest)
31
how is the small intestine held in place?
initial segment (duodenum) of small intestine is retroperitneal
rest of the small intestine is held in place by mesentary, allows movement but prevents tangling.
32
what does the mesentary contain and what is it made of
made of peritoneum, contains arteries, veins, nerves and lymphatics
33
where do the lymph lacteals drain?
cisterna chyli, thoracic duct then to the left subclavian vein
34
where does the nutrient rich deoxygentaed blood from the small intestine entering the myenteric veins drain into?
the hepatic portal veins
35
what are the plicae circulares?
permanent large folds in the small intenstine
these have a core of submucosa with a overlying mucosa layer.
36
how does villi movement occur, and why is it important?
the muscularis mucosae
movement allows for more contact with nutrients so more can be absorbed.
37
what layer are the villi part of, what is their core made of and what does each one contain
the mucosa layer
a core of lamina propria
each contains a lymph lacteal (products of fat digestion)
and a capillary network (product of protein and carb digestion)
38
what is glycocalyx and what is its function?
glycoproteins that attatch enzymes acting as a glue.
39
what are the 5 main small intestine epithelial cells and what are their functions.
enterocytes- absorbative cells
goblet cells- secrete mucous for protection
paneth cells- granules, antibacterial enzymes
endocrine cells- secrete hormones
stem cells- can replenish any cells
*high cell turnover in the small intestine as they are being used so much
40
what regulates the passage of material from small to large intestine
the ileocecal valve
41
what parts of the large intestine are parietal and which are retroperitoneal
ascending and decending are retroperitoneal
transverse and sigmoidal are intraperitoneal
42
what are the teniae coli, haustra and omental appendicesin the large intestine?
teniae coli= bands of longitudinal muscle these allow for stronger contraction
haustra= the pouches
omental appendices= sacs of fat
43
why doesnt the large intestine have as much villi?
Because we dont need as large of a surface area as we arent doing as much absorption
has more glands for lubrication to slide things through
44
Internal vs external anal sphincer
internal is smooth muscle (involuntary control)
external is skeletal muscle (voluntary control)
45
what is the defication reflex
movement of feces into the rectum stimulates stretch receptors, causing the internal anal sphincter to relax (short local reflex)
long reflex also activated which causes mass movements to push the feces towards the sigmoidal colon making the internal anal sphincter relax even more.
46
what is the appendix attached to ?
the cecum
47
how does the gall bladder connect to the duodenum?
through the cystic duct and the bile duct
48
what 3 things travel within the lesser omentum?
hepatic portal vein, hepatic artery and the bile duct.
49
what cells in the liver produce the bile?
rows of hepatocytes
they detoxify blood and produce bile
50
what is a portal triad in the liver?
at every corner of a lobule we see a bile duct, a hepatic vein and a hepatic artery
51
what direction does blood and bile flow in the liver lobules?
blood flows towards the central vein in the centre of the lobule
bile secreted into canaliculi runs the opposite direction out to the bile ducts on the corners of the lobules to be transported to the gall bladder.
52
where does the central vein in the liver drain to
central vein--> hepatic vein--> inferior vena cava
53
What is the submucosal and the myenteric plexus in control of ?
submucosal is the regulation of secretion
myenteric is the regulation of motility
54
what are enteroendocrine cells
endocrine cells in the GI system
epithelial cells with receptors that release hormones
55
what does the secretion of gastrin stimulate
the production of chief cells and parietal cells
56
what are the three motility patterns of the stomach?
relaxation- fundus and body which allows for storage
retropulsion- peristalisi and contraction of pyloric sphincter for mechanical digestion and mixing
contraction and relaxation of pyloric sphincter- gastric empyting and controlled delivery of chyme to duodenum.
57
what are the three motility patterns of the small intestine?
segmentation- mixing back and forward for exposure to absoptive surfaces
peristalsis- movement of chyme through SA. main peristalsis occurs after most nutrients have been absorbed
contraction and relaxation of of ileocecal sphincter- sphincter between small and large intestine to deliver chyme.
58
what are the 3 motility patterns of the large instestine?
-large periods of inactivity
-segmentation throughout large intestine for exposure to absorption surfaces.
peristalsis- drives feces into rectum to initiate defication.
59
what is the composition of the salivary secretion?
mucus for lubrication
dilute NaCl/NaHCO3 for dilution of food, optimum ph for enzymes (slightly basic) and for hygiene.
digestive enzymes
lingual lipase and salivary amylase
60
what occurs to the rate of gastric secretions when eating and what are the different cells producing?
extra secretion added to basal/resting rate.
goblet cells: mucus and bicarb
parietal cells: HCL acid ( converts pepsinogen to pepsin) optimum for it to work.
intrinsic factor: absorption of vit b12 in SA
cheif cells: pepinsogen
61
what is carbonic anhydrase?
the production of H+ and HCO3- from CO2 and H2O.
62
what is the cephalic phase of gastric secretion?
20% of gastric secretion
stomach prepping for food to arrive
activates CNS, parasympathetic stimulating ENS and submucosal plexus for increase secretion.
submucosal stimulates goblet cells, chief cells, parietal cells and G cells
63
what is the gastric phase of secretion?
70% gastric secretion
g cells, chemo/mechanoreceptors activating ENS for submucosal plexus and mytenteric plexus to increase secretion and motility
G cells secreting gastrin= increased gastric motility
increased retropulsion
increased sectrtion of mucus, bicarb, acid and pepsinogen
64
what is the intestinal phase of secretion?
10% of secretion
when the chyme begins to arrive in duodenum it released duodenal hormones CCK and GIP and secretin. activating sympathetic nervous system to inhibit the myenteric and submucosal plexus therefore decreasing gastric secretion and motility.
65
what does the arrival of fatty acids and amino acids in the duodenum do to secretions
receptors detect this and the enteroendocrine cells release CCK, this stimulates release of pancreatic juice with digestive enzymes from the acinar cells
66
why are pancreatic proteolytic enzymes secreted as inactive precursors?
so they don't digest proteins insdie pancreatic acinar cells, they only become activated in teh duodenum.
67
what is enterokinase?
it is bound to the duodenal membrane and it converts trypsinogen to trypsin
once activated trypsin then can activate other enzymes.
68
what occurs due to the arrival of acidic chyme into duodenum?
decreasing PH activating receptors for enteroendorcine cells to release secretin which stimulates pancreatic duct cells to release bicarb.
bicarb provides optimum PH for pancreatic enzymes.
69
what causes the initial release of bile from the gall bladder
the arrival of fatty acids in duodenum causing CCK to be secreted resulting in a release of bile from the gall bladder
70
what is enterohepatic circulation
the transportation system for the reabsorption of bile from the illeum back to the liver to be re-secreted.
71
what is the strongest stimulant for the liver to produce more bile
the bile returning to the liver through enterohepatic circulation as its signaling to the hepatocytes that bile has recently been released from the gall baldder.
72
what are the secretions in the large intestine?
mucus for lubrication
73
what are two macromolecules that are important sources of energy ?
carbohydrates and lipids
74
what are the essential lipids for our bodies?
omega-3 and -6 fatty acids
fat soluble vitamins a, d, e & k
75
what are the small molecules that nutrients are broken down into to be absorbed in the small intestine
monosaccarides
amino acids or small peptides
free fatty acids or monoglycerides
76
why can carbohydrates in the form of starch be digested by the body but carbohydrates in the form of cellulose cannot?
because amylase can break the alpha bonds between the glucose molecules but it cannot break the beta bonds between the glucose molecules in the cellulose
77
what is the optimum ph for...
salivary enzymes
gastric enzymes
pancreatic enzymes
salivary- slightly basic
gastric- acidic pH
pancreatic- slightly basic
78
what are the two stages of chemical digestion?
1) luminal digestion- starting chemical digestion from acids and enzymes that have been secreted into lumen of the GIT
2) contact digestion- finishes chemical digestion. enzymes attatched to the brush boarder of enterocytes
79
what are the enzymes for sucrose, lactose and maltose?
sucrase
lactase
maltase
80
what are the the pancreatic proteases that break down large polypeptides into small polypeptides?
trypsin
chymotrypsin
carboxypeptidase
81
where does the digestion of fats occur and what is the main digestive enzyme for fats?
only luminal digestion in the stomach and small intestine
pancreatic lipase is the main digestive enzyme
82
what are the four phases of fat digestion
1) Emulsification- mixing
2) emulsification- stabilisation through bile salts
3) digestion (hydrolysis), enzymes
4) formation of micelles, bile salts
*1&2 occur in the lumen of stomach and small intestine
*3&4 occur in the lumen of the small intestine
83
what is occuring during emulsification mixing
large lipid droplets broken down into smaller stabilised droplets. increases surface area for digestion
this is completed through motility- retropulsion and segmentation
84
what occurs during emulsification stabilising
bile salts coat the emulsification droplets which stabilises them so they dont form back into larger droplets
85
what property of bile salts allows them to emulsify fat droplets?
theyre amphipathic, having a hydrophobic side that binds to the fat and a hydrophilic side that faces outwards
86
what occurs during the hydrolysis phase of fat digestion
the lipase enzymes and its cofactor colipase (anchors lipase to the surface of the droplet) converts triglycerides to x2 free fatty acids, 1x monoglyceride
this occurs in the small intestine
87
what occurs in the formation of micelles step of fat digestion
as the products of fat are insoluble in water theyre kept in solution through the formation of micelles which contain the free fatty acids and monoglycerides.
20-30 molecules
88
what does the rate that food/chyme travelling through the gastrointestinal system depend on?
storage- in stomach and small intestine
peristalsis in stomach, small and large intestines
89
what are the factors for the paracellular pathway?
occurs between epithelial cells through tight junctions
relatively non selective- if the tight junction is leaky and the particle is small enough it can move through the paracellular pathway but if the tight junctions are tight then particles cannot move through the paracellular pathway.
requires a gradient as the driving force
90
what are factors for the transcellular pathway
through the epithelial cells crossing two cell membranes.
lipid soluble particles are able to diffuse through the membrane assuming a gradient is present.
water soluble particles need channels or transporters and require a driving force eg atp or gradient.
91
what are some anatomical adaptions that have occured to maximise surface area
length of intestine (6m)
circular folds (pliquae circulares)
villi
microvilli
92
how do we prevent buildup of particles in the interstitual fluid after absorptiob
have a high blood flow to the intestines and the blood vessels are close to the basolateral side of the epithelial cells which allows active transport to push particles into the blood vessles and out into the cells
93
what are the two mechanisms for carbohydrate transport, what pathway do they occur with and what is their driving force?
passive absorption- through paracellular pathway. glucose molecules diffuse down their concentration gradient across the leaky tight junctions
active absorption- through transcellular pathway. driving force is the sodium gradient generated by the Na+/K+ ATPase
94
what are the two mechanisms for protein transport, what pathway do they occur with and what is their driving force?
passive absorption- through paracellular pathway, amino acids diffuse down their concentration gradients through leaky tight junctions.
active absorption vis transcellular pathway- driving force is the sodium gradient generated by the Na+/K+ATPase
95
how does protein absorption differ for di and tri peptides?
they can only be absrobed through active absorption through the transcellular pathway
driving force is the negative membrane potential established by the Na+/K+ ATPase creating the electrical gradient for H+
once inside the epithelial cells the peptidase turns the peptides into amino acids so they can then enter the interstitual fluid through the amino acid transporter.
96
what occurs for the absorption of free fatty acids and monoglycerides. include what happens at the lumen and apical membrane, intracellularly and at the basolateral membrane
lumen and apical memebrane- free fatty accids move by simple diffusion from micelles into the cell (micelle not absorbed and bile salts absorbed in the ileium)
intrecellular- transported to ER and resythnthesised to triglycerides and packed into chlomircons.
basolateral membrane- tags exocytosed in chylomicrons enter the lymp lacteals in the villi.
