exam 2 Flashcards
(134 cards)
1
Q
intrinsic control of the GIT
A
enteric nervous system
GI hormones
2
Q
extrinsic control of the GIT
A
vagus n.
splanchnic n.
non-GI hormones
3
Q
where is the enteric nervous system located
A
in the GI wall
4
Q
located b/w the submucosa and circular m.
regulates mucus secretion and food absorption
A
plexus submucosus
5
Q
located in the muscularis externa b/w the muscle layers
controls of tone and contraction rhythm
A
plexus myentericus
6
Q
the muscle bundles of the enteric nervous system connect with one another through
A
gap junctions
7
Q
enteric neurons secrete neurotransmitters from
A
varicosities
8
Q
which type of sensory nerve cell recognizes stretching of the intestinal wall or volume changes
A
mechanosensitive cells
9
Q
which type of sensory nerve cell detects the presence of nutrients in the GI lumen, changes in osmolarity and changes in the pH
A
chemosensitive cells
10
Q
where do the axons of sensory nerve cells travel to
A
enteric nerve cells and CNS
11
Q
interneurons send signals to ___
A
motor neurons
12
Q
muscle motor neurons are located in the ____
A
plexus myentericus
13
Q
secretory motor neurons are located in the ___
A
plexus submucosus
14
Q
____ motor neurons are located in both plexuses; they regulate the tone of blood vessels
A
vaso motor neurons
15
Q
non-noradrenergic, non-cholinergic (NANC) neurotransmitters include
A
NO
VIP
substance P
ATP
16
Q
NANC inhibitory; reduces GIT motility
A
NO
17
Q
NANC inhibitory; relaxes sm. m sphincters
possibly stimulatory to secretory glands
A
VIP
18
Q
NANC excitatory; inc secretion and GIT motility
A
substance P
19
Q
which SNS neurotransmitter inhibits GI activity
A
norepinephrine
20
Q
which PSNS neurotransmitter excites GI activity
A
acetylcholine
21
Q
visceral afferents are stimulated by:
A
irritation of gut mucosa
excessive gut distention
presence of specific chemical substances in the gut
22
Q
____ fibers of the PSNS become integrated with fibers of the ENS
A
pre-ganglionic
23
Q
PSNS post-ganglionic neurotransmitters are
A
acetylcholine
VIP
NO
24
Q
SNS post-ganglionic neurotransmitter
A
noradrenaline
25
the frequency of slow waves determines
rhythm of GI contractions
26
AP of the GIT; occur when the RMP of the GI sm. m. becomes more positive than -40mV
spike potentials
27
slow waves originate in specialized smooth muscle cells called _____; "electrical pacemaker" for smooth muscle cells
interstitial cells of cajal (ICC)
28
stimuli for depolarization in the GIT
stretching
Ach release
GI hormones
29
stimulus for hyperpolarization in the GIT
NEPI and EPI
30
which reflexes are integrated entirely within the gut wall
control of GI secretion
peristalsis
formation of mixing contractions
local inhibitory effects
31
reflexes from the gut to the prevertebral sympathetic ganglia
gastrocolic reflex
enterogastric reflex
colonoileal reflex
32
signals from the stomach that cause evacuation of the colon
gastrocolic reflex
33
signals from the colon and small intestine to inhibit stomach motility and stomach secretion
enterogastric reflex
34
signals from the colon that inhibit emptying of ileal contents into the colon
colonoileal reflex
35
reflexes that travel from the gut to the spinal cord or brainstem
gastric motor and secretory activity
pain reflexes
defecation reflex
36
during peristalsis, how are the muscles behind the site of distension
longitudinal relaxed
circular contracts
37
during peristalsis, how are the muscles distal to the site of distension
longitudinal contracts
circular relaxed
38
during peristalsis, contraction of which muscle moves the chyme
circular
39
contraction of muscles during peristalsis occurs when motor neurons release
Ach and substance P
40
relaxation of muscles during peristalsis occurs when motor neurons release
NO
VIP
ATP
41
reflex that controls motility of the GI muscle layers in response to distention by chyme; ex. receptive relaxation of the stomach in response to mastication and deglutition
vagovagal reflex
42
which region of the stomach is the gastric reservoir
proximal
43
which region of the stomach is the gastric pump
distal
44
true or false: there is no change in intraluminal pressure of the stomach when it enlarges
true
45
sequence of inflow into the gastric pump
1. tonic contraction of fundus
2. strong peristaltic wave in the corpus
3. passage into grinder and then pylorus
4. emptying into duodenum
46
what happens if a piece of food is still too big to go through the pylorus
pyloric sphincter closes so it can go through another mixing cycle
47
during feedback relaxation of the stomach, what is released when nutrients reach the duodenum
CCK
48
two patterns of movement in the small intestine during the digestive period
propulsive pattern
non-propulsive pattern
49
type of contraction during the propulsive pattern
peristaltic
50
type of contraction during non-propulsive pattern
segmentation, localized contractions of circular muscle
51
fx of non-propulsive pattern
splits the chyme for better digestion
52
time between meals when the stomach and sm. intestine are empty
interdigestive period
53
motility pattern during interdigestive period
migrating motoric complex (MMC)
54
fx of migrating motor complex
help push indigested material out of the intestine
control bacterial population
55
phase I of MMC
motoric rest, no contractions
56
phase II of MMC
intermittent and irregular contractions
57
phase III of MMC
strong peristaltic contractions from stomach to colon
58
fx of antiperistaltic waves in the large intestine
impede movement of ingesta for more intense mixing
59
where is vomiting coordinated
brainstem
60
stimuli before food intake, visceral afferent reaching the vomiting center, or stimulation of the _____ can trigger vomiting
chemoreceptor trigger zone
61
occurs when absorption is inadequate to recover all secreted water; can occur because of destructed villi from infection
malabsorptive diarrhea
62
occurs when the rate of intestinal secretion inc and overwhelms absorptive capacity; can occur because of enterotoxins stimulating the production of cAMP and opening of Cl channels
secretory diarrhea
63
which sphincter involved in the defecation reflex is made of skeletal muscle
external
64
how is the internal anal sphincter innervated
parasympathetic - relaxation
sympathetic - constriction
65
peristaltic movement of feces into the rectum and relaxation of internal anal sphincter; causes the urge to defecate
rectosphincteric reflex
66
in the ruminant stomach, enzymes for digestion are of ___ origin
microbial
67
fx of the reticular groove
directs milk directly into abomasum, bypassing the rumen in newborns
68
what type of epithelium are the forestomachs lined with
stratified squamous
69
what accelerates development of the forestomach in a newborn
solid feed and contact with adult ruminants
70
non-ruminant period of a newborn
birth to 3 weeks
71
most protozoa in the ruminant stomach are ____ (ciliated/flagellates)
ciliated
72
in the rumen, bacteria are ingested by
protozoa
73
which VFA goes to the liver to enter gluconeogenesis
propionate
74
which VFA goes to adipose tissue to produce fatty acids
acetate
75
which part of the plant cell acts as an important substrate for fermentative digestion
plant cell walls
76
in ruminants, cellulose, hemicellulose and pectin are hydrolyzed by
cellulase
77
what is the fate of monosaccharides released from hydrolysis of polysaccharides in the rumen
further metabolized by microbes
78
within the microbial cell, glucose enters the glycolytic pathway and produces ___
2 pyruvate
2 NADH
2 ATP
79
pyruvate is used in the ruminant to produce
VFAs
80
microbes produce ____ which form short chain peptides to be absorbed into the microbial cell bodies
endopeptidases
81
what are the two fates of peptides once in the microbial cell
form microbial protein
further degraded into VFA pathway
82
in rumen microbes, amino acids are synthesized intracellularly by
hydrolyzed peptides
NH3
VFA
83
in ruminants, amino acids contribute to
synthesis of microbial protein
synthesis of VFA and ammonia
84
what must happen to an amino acid to enter the VFA pathway
deamination
85
what makes ruminants efficient conservers of nitrogen in conditions of low dietary protein
urea recycling - portion of urea reaching the rumen is resynthesized into protein that will contribute amino acids
86
in ruminants, what are the 2 sources of urea to be synthesized in the liver
urea from deamination
nitrogen absorbed as ammonia
87
in fermentative digestion, fats are hydrolized by microbial lipases; the glycerol and sugars go into the VFA pathway, while the fatty acids released ___
are hydrogenized and go into the abomasum and sm. intestine for absorption
88
typical ruminal acetic/propionic/butryic acid concentration ratio
70:20:10 - high forage
60:30:10 - high grain
89
vitamins synthesized by microbes include
C, K, B1, B12
90
high concentration of which ion, present in young pastures, competes with the absorption of magnesium
K+
91
functions of the omasum
concentration of ingesta - absorption of H2O
SCFA (VFA) absorption
Na and Cl absorption
HCO3 reabsorption
92
what is the function of primary rumen contractions
reduce particle size
93
what is the function of secondary rumen contractions
force gas towards cranial portion of the rumen
94
where do cranial moving contraction of the rumen start
caudo-dorsal blind sac
95
where does the regurgitation reflex begin
mid-dorsal rumen
96
where is the eructation center located
medulla
97
in which sac does the eructation center receive afferent fibers from mechanoreceptors
dorsal sac
98
legume bloat occurs because
the presence of gas is not detectable by mechanoreceptors, due to being trapped in bubbles
99
the reticulorumen motility is controlled by
ENS and vagus nerve
control center: brain stem
100
changes in motor distention, consistency of ingesta, pH, VFA concentrations and ions will cause a (inc/dec) in rumen motility
decrease
101
ruminant ketosis is associated with
hypoglycemia
102
stimulated by PTH in response to hypocalcemia
calcitriol
103
hormone activator, renal regulation of BP
renin
104
stimulates the absorption of calcium
calcitriol
105
secreted in response to acute drop in plasma volume and BP
renin
106
stimulates Na reabsorption to inc blood volume and BP
angiotensin II
107
first step in urine formation
filtration of fluid through glomerular capillaries
108
components of the filtration barrier
fenestrated capillary endothelial cells
glomerular basement membrane - glycoproteins
podocytes
109
3 layers of the glomerular basement membrane
1. lamina rara interna
2. lamina densa
3. lamina rara externa
110
out of the three glomerular basement membrane layers, which is especially rich in proteins
lamina densa
111
the glomerular capillaries are impermeable to proteins, meaning the glomerular filtrate is _____
protein free
112
main driving force for filtration
hydrostatic pressure of the glomerular capillary
113
99% of GFR returns to the extracellular compartment by _____
tubular reapsorption
114
properties of indicator substances of GFR
1. must be freely filterable
2. filtered amount must not change due to reabsorption or secretion in the tubule
3. must not be metabolized in the kidney
4. must not alter renal fx
115
if [creatinine] in plasma is elevated, GRF is ____
reduced
116
which reflex detects changes in glomerular perfusion
myogenic reflex
117
detects changes in tubule fluid delivery
tubuloglomerular feedback (TGF)
118
renin is synthesized in the ____ cells, in the wall of the afferent arteriole
juxtaglomerular
119
macula densa cells sense changes in ____ in the distal tubule
NaCl
120
fx of TGF
prevents a flow rate that would exceed transport capacity of the tubular system
121
2 vasodilators that cause vasodilation and inc GFR
NO (NOS)
PGE2 (COX-2)
122
vasoconstrictors that mostly effect the efferent arterioles
norepinephrine
epinephrine
endothelin
angiotensin II
TXA2
123
what happens to GFR is RBF inc
inc GFR
124
what happens to GFR is systemic pressure inc
inc GFR
125
what happens to GFR if afferent arteriole tone inc
dec GFR
126
what happens to GFR if efferent arteriole tone slightly inc
inc GFR
127
what happens to GFR if efferent arteriole tone strongly inc
dec GFR
128
what happens to GFR if hydrostatic pressure of bowman's capsule inc
dec GFR
129
nephron segment that filters the blood of solutes, water, urea and creatinine to make primary urine
glomerulus
130
nephron segment that reabsorbs most filtered solutes, reabsorbs H2O, excretes waste and xenobiotics
proximal tubule
131
nephron segment that maintains medullary hypertonicity, reabsorbs H2O, Na and Cl
thin limbs of henle's loops
132
nephron segment that reabsorbs Na, K, Cl; dilutes tubule fluid and maintains medullary hypertonicity
thick ascending limb
133
nephron segment that reabsorbs Na, Cl, Ca, Mg; connecting segments regulate acid, HCO3-, NH3, Ca, Na, K and H2O excretion
distal convoluted tubule
134
nephron segment that regulates acid, HCO3-, NH3, Na, K, and H2O excretion/reabsorption to make final urine
collecting ducts
