Exam 1 (Intro + Neuroendocrine) Flashcards
1
Q
Animals require what 2 things?
A
- energy
- basic chemical constituents (amino acids)
2
Q
What is the purpose of basic chemical constituents like animo acids?
A
growth + repair
3
Q
What is the drive to eat?
A
satisfy energy needs
4
Q
What is assimilation?
A
taking nutrients into body
5
Q
What two processes occur with assimilation?
A
digestion
absorption
6
Q
Definition of digestion
A
ingested food changes to suitable form for absorption
7
Q
Digestion occurs (inside/outside) the body tissues.
A
outside
8
Q
3 examples of mechanical component to digestion
A
chewing
kneading (peristalsis)
ventriculus (gizzard) + grit - bird
9
Q
What 4 things are GI exocrine secretions?
A
water
electrolytes
enzymes
mucus
10
Q
What is the purpose of electrolytes in GI exocrine secretions?
A
nutrient absorption
11
Q
What is the purpose of water + electrolytes in GI exocrine secretions?
A
provide volume
dissolution (dissolving)
control acid/base environment
12
Q
Enzymes are powerful in which locations?
A
saliva
pancreas
intestines
microbe
13
Q
Function of hydrolytic enzymes
A
use water to break bonds
14
Q
Functions (2) of mucus GI secretions
A
lubricate dry matter to prevent injury
bacterial barrier
15
Q
Digestion barrier functions to keep the body safe from what 3 things?
A
autodigestion
bacterial invasion
physical damage
16
Q
What 3 things are part of the digestion barrier?
A
epithelium
mucus
proenzymes
17
Q
What type of epithelium is present from the mouth to the cardia of the stomach?
A
stratified squamous
18
Q
What type of epithelium is present in the stomach to the intestines?
A
simple columnar
19
Q
What type of epithelium is present in the anus?
A
stratified squamous
20
Q
Proenzymes are produced (active/inactive) and active in the _____.
A
inactive (no cell interference)
GI lumen
21
Q
Carnivores have a (simple/complex) GI tract and the small intestine is ____x the body length.
A
simple
4x
22
Q
Carnivores have a (short/long) transit time.
A
short
23
Q
Omnivores have a (simple/complex) GI tract and the small intestine is ___x the body length.
A
complex
10-15
24
Q
______ is retained for microbial digestion in omnivores.
A
plant matter
25
Which species dietary type has compartmentalized large intestines?
omnivore
26
What are the 2 strategies herbivores use to get nutrients?
hind-gut fermenters
foregut fermenters
27
(Hindgut/Foregut) Fermenters are considered monogastric.
hindgut
28
Hind-gut Fermenters have a compartmentalized large intestine that generates _______.
volatile fatty acids (VFA) or short chain FA
29
Hind-gut Fermenters have a small intestine that is ____x their body length.
6
30
Example of a hind-gut fermenter vs. foregut fermenter
hind-gut: horse
foregut: sheep
31
Foregut fermenters have a large, complex forestomach before their _____ stomach.
true
32
_____ can occur before the "true" stomach in foregut fermenters.
microbial digestion
33
Are hind-gut or foregut fermenters more efficient?
foregut
34
The ingested form of proteins have a (loose/tight) 3D molecular structure.
tight
35
What process is used to digest proteins?
hydrolysis (enzymatic digestion)
36
What is the absorbable form of proteins?
amino acids, dipeptides/tripeptides
37
Protein digestion pathway
epithelium --> blood --> portal vein --> liver
38
Ingested form of carbohydrates
complex polysaccharides
39
Ingested form of soluble carbohydrates vs. insoluble
Soluble: starches
Insoluble: cellulose
40
How are starches digested?
hydrolysis of 1-4 glycosidic link by mammal enzymes
41
How is cellulose digested?
hydrolysis of beta 1-4 glycosidic link by bacterial enzymes
42
Absorbable form of starches vs. cellulose
starches: monosaccharides
cellulose: volatile fatty acids
43
Starch (carb) digestion process
starch --> monosaccharide --> blood --> portal V --> liver
44
Cellulose (carb) digestion process
cellulose --> VFA across epithelium --> blood --> portal V --> liver
45
Ingested form of fat
triglycerides (hydrophobic)
46
What process does fat undergo by bile salts?
emulsification
47
What do triglycerides break into after emulsification?
micelles for better enzyme access
48
What process is fat digested by?
hydrolysis
49
Micelles release _____, _____, and _____.
glycerol
monoglycerides
free fatty acids
50
Micelles are re-esterified into triglycerides and exported in ______.
chylomicra
51
Chylomicra
glycoprotein triglycerides packaged to make them water soluble
52
Digested fat enters ______.
lymph
53
Why does digested fat enter lymph? (2)
too large for capillary pores
limited liver availability
54
Process by which digested foods enter blood or lymph
absorption
55
What 2 processes can occur during absorption?
active transport
passive transport
56
(T/F) Active transport is only paracellular.
False - only transcellular
57
What transporters are on the luminal side?
Nutrient transporters
Na/H exchanger
Cl/HCO3 exchanger
58
What transporters are on the basolateral side?
Na/K ATPase
Cl/HCO3 cotransporters
Facilitated diffusion transporters
59
Na/K ATPase uses _______ transport and _____ is transported out of the cell which makes the inside of the cell ____.
primary active
Na+
negative
60
Two types of transporters that are secondary active
Na+ coupled transporters
Electroneutral transporters
61
What 2 transporters are part of the electroneutral transporters?
Na/H exchanger
Cl/HCO3 exchanger
62
The electroneutral transporters mainly move ______.
electrolytes
63
Passive transport is (transcellular/paracellular) for lipids/fatty acids, and (paracellular/transcellular) for electrolytes/water.
transcellular
paracellular
64
Another name for paracellular transport
intercellular
65
The stomach is made of ______ epithelium and what other structure?
simple columnar
gastric pits
66
The small intestine is made of _____ epithelium and what 2 other structures?
simple columnar
crypts + villi
67
Function of villi
increase surface area + absorption (for nutrients)
68
(T/F) The large intestine has crypts and villi.
False - NO villi
69
What is crypt epithelium?
stem cell compartment of intestine
70
(T/F) There can be healthy forms of autodigestion.
True - ~10 cells per day autodigested in lumen
71
What 5 cell types do stem cells give rise to?
absorptive cell
goblet cell
enteroendocrine cell
paneth cell
tuft cell
72
Which cell type that stem cells give rise to makes up the majority?
absorptive cell
73
What cell type releases mucous granules?
goblet cell
74
What cell type produces hormones?
enteroendocrine cell
75
What cell type secretes antimicrobial peptides + growth factors?
paneth cell
76
What cell type detects parasite products + activates immune system?
tuft cell
77
Where does anion secretion occur?
crypts
78
Anion secretion is a process for ____ and ____ secretion by epithelium.
NaCl
water
79
3 functions of anion secretion
flush surface
hydrates mucous
adjusts pH in lumen
80
In anion secretion, anions leave the cell through _____.
CTFR
81
CFTR is a pore permeable to __ and __ and secretes __ and __.
Cl- & HCO3
Na+ & water
82
What two substances move paracellularly?
electrolytes + H2O
83
Electrolytes + H2O move paracellularly (with/against) gradient and are rate limited by _____.
with
tight junctions
84
Are each tight junctions considered leaky or tight?
small intestine
large intestine
stomach
leaky
tight
tight
85
Why are tight junctions in small intestine "leaky"?
NaCl + H2O leak to maintain fluidity for digestion
86
Why are tight junctions "tight" in large intestine?
retain net absorption
conserve ECF volume
87
Why are tight junctions "tight" in stomach?
decrease leakage of HCl (hydrochloric acid)
88
Gap junctions have (low/high) electrical resistance.
low
89
Term for when nerves depolarize a few myocytes and it spreads via gap junctions.
Ephaptic conduction
90
Term for myocytes contracting in unison
functional syncytium
91
What specialized neurons set the pace of slow waves?
Interstitial cell of Cajal (ICC)
92
Term for regular oscillations in membrane potential
slow waves
93
Term for when depolarization phase of slow waves exceeds threshold
spike potential
94
______ channels open --> contraction when depolarization exceeds threshold.
voltage-gated Ca2+
95
Term for anatomical locations where slow waves regularly exceed threshold by ICC
pacemakers
96
What 2 ways is contraction of visceral smooth muscle modulated?
1. stretch depolarization
2. regulation by ANS + humoral agents
97
PSNS opens ___ channels and leads to (depolarization/hyperpolarization) while SNS opens ___ channels and leads to (depolarization/hyperpolarization).
Ca2+
depolarization
K+
hyperpolarization
98
2 contraction modes of visceral smooth muscle
phasic
tonic
99
What contraction mode is a long-term contraction with neural influence?
tonic
100
Tonic contraction is a property of _____ muscle.
circular smooth
101
What contraction mode is timed by slow waves?
phasic
102
Peristalsis is an example of (phasic/tonic) contraction.
phasic
103
What nervous system is made up of the ANS and outside the gut wall?
extrinsic
104
What nervous system is called the "brain of the gut" with 2 parts?
enteric
105
2 parts of the enteric nervous system
myenteric (auerbach's) plexus
submucosal (meisner's) plexus
106
Which part of the enteric nervous system has a deep motor plexus in circular smooth muscle?
submucosal (meisner's) plexus
107
Which part of the enteric nervous system has ICC (pacemaker cells of peristalsis)?
myenteric (auerbach's) plexus
108
Longitudinal smooth muscle is (contracted/relaxed) by default, and with neural effect (contracted/relaxed).
relaxed
contracted
109
Circular smooth muscle is (contracted/relaxed) by default, and with neural effect (contracted/relaxed).
contracted
relaxed
110
What generate slow waves for peristaltic contractions of smooth muscle?
Interstitial cells of Cajal
111
What are 3 components of the enteric nervous system?
afferent neurons
enteric interneurons
effector neurons
112
Function of afferent neurons
sensory
113
Function of enteric interneurons
integrate input
determine appropriate physiological response
114
Which two components of enteric nervous system are primarily cholinergic?
afferent neurons
enteric interneurons
115
What 3 types of afferent neurons are in mucosa?
chemoreceptors
osmoreceptors
mechanoreceptors
116
What type of afferent neurons are present in muscle layers?
mechanoreceptors
117
What to chemoreceptors detect?
pH, amino acids
118
What do osmoreceptors detect?
change in osmotic pressure
119
What do mechanoreceptors detect?
stretch
120
Function of effector neurons
physical response
121
Main function of effector neurons
promote digestion
122
Effector neurons promote digestion by stimulating what 4 things?
1. peristalsis + mixing
2. net fluid secretion
3. vasodilation of vasculature
4. enteroendocrine cell degranulation
123
Purpose of net fluid secretion stimulated by effector neurons
dissolve nutrients
decrease NaCl absorption (villi) and NaCl secretion crypt
124
Enteroendocrine cell degranulation adds _______.
additional hormone control
125
Vasodilation of splanchnic vasculature by effect neurons supports _____ and _____.
absorption
secretion
126
What are the 2 major classes of effector neurons?
1. cholinergic neurons
2. inhibitory neurons
127
Cholinergic neurons produce _____ and are _______.
acetylcholine
muscarinic/metabotropic
128
Cholinergic neurons (relax/contract) longitudinal smooth muscle, (stimulate/inhibit) secretion/antiabsorption, and _____ cell degranulation.
contract
stimulate
enteroendocrine
129
Inhibitory neurons are non______ and _____.
nonandrenergic
noncholinergic
130
What 3 neurotransmitters are used by inhibitory neurons?
VIP (vasoactive intestine peptide)
NO (nitric oxide)
ATP (adenosine triphosphate)
131
Inhibitory neurons (stimulate/relax) circular smooth muscle, (inhibit/stimulate) secretion/antiabsorption, and (constrict/dilate) splanchnic vasculature.
relax
stimulate
dilate
132
Inhibitory neurons inhibit circular smooth muscle contraction by what NTs?
NO + VIP
133
Inhibitory neurons stimulate secretion/antiabsorption by what NT?
VIP
134
Inhibitory neurons stimulate dilation of splanchnic vasculature by what NT?
NO
135
(T/F) Peristalsis can occur without PSNS/SNS influence.
True - solely with enteric NS
136
Default state of circular smooth muscle layer is (contraction/relaxation).
contraction
137
Default state of longitudinal smooth muscle layer is (contraction/relaxation).
relaxation
138
Main control of circular smooth muscle layer is by _____ neurons which cause (contraction/relaxation).
inhibitory neurons
relaxation
139
Main control of longitudinal smooth muscle layer is by ______ neurons which cause (contraction/relaxation).
cholinergic
contraction
140
What physically happens to the lumen when longitudinal muscle = relaxed & circular = contracted?
decrease lumen diameter
decrease retrograde movement
141
Oral to a food bolus, cholinergic & inhibitory neurons are (on/off) while aboral to bolus they are (on/off).
off
on
142
After a food bolus, longitudinal muscle is (contracted/relaxed) while circular M is (contracted/relaxed).
contracted
relaxed
143
What physically occurs in the lumen when longitudinal M contracts & circular M relaxes?
opens lumen for bolus to move forward
