Exam 2 - Lecture Notes Flashcards
1
Q
thyroxine (T4) and triiodothyronine (T3) effect
A
stimulate basal metabolic rate
2
Q
calcitonin effect
A
reduces blood Ca2+ levels
3
Q
parathyroid hormone effect
A
increases blood Ca2+ levels
4
Q
aldosterone effect
A
increases blood Na+ levels
5
Q
cortisol, corticosterone, cortisone effect
A
increase blood glucose levels
6
Q
epinephrine and norepinephrine effects
A
stimulate fight or flight response
7
Q
insulin effect
A
reduce blood glucose levels
8
Q
glucagon effect
A
increases blood glucose levels
9
Q
testosterone effects
A
stimulates development of male secondary sex characteristics and sperm production
10
Q
estrogens and progesterone effects
A
stimulate development of female secondary sex characteristics and prepare the body for childbirth
11
Q
the release of adrenal glucocorticoids is stimulated by the release of hormones from the _________ and ________ _________
A
hypothalamus and pituitary gland
12
Q
the signal to release glucocorticoids is ___________ (inhibited/stimulated) when glucocorticoid levels become elevated causing ________ (negative/positive) signals to the pituitary gland and hypothalamus
A
inhibited; negative
13
Q
what class of hormones are glucocorticoids?
A
steroid hormones
14
Q
glucocorticoids are pleiotropic. what are the many effects it can have?
A
- glucose metabolism
- chronic stress response
- anti-inflammatory
15
Q
main glucocorticoids in mammals
A
cortisol and cortisone
16
Q
main glucocorticoids in birds and rodents
A
corticosterone
17
Q
_______ _______ directly accelerates the rate of protein synthesis in skeletal muscles and bones
A
growth hormone
18
Q
what does IGF-1 stand for?
A
insulin-like growth factor 1
19
Q
what is activated by growth hormones and indirectly supports the formation of new proteins in muscle cells and bones?
A
IGF-1
20
Q
GH is one of the most ___________ hormones
A
pleiotropic
21
Q
the _____ (organ) releases IGF-1, further stimulating growth effects
A
liver
22
Q
what are the effects of GH?
A
- glucose-sparing effect
- growth effects
- diabetogenic effect
23
Q
what is the glucose sparing effect of growth hormone?
A
stimulates adipose cells to break down stored fat, fueling growth effects
24
Q
what are the growth effects caused by growth hormone?
A
it targets bone cells, muscle cells, nervous system cells, and immune cells. It increases the uptake of amino acids from the blood. enhances cellular proliferation and reduces apoptosis.
25
what inhibits growth hormone?
a high levels of IGF-1 is perceived by the hypothalamus and GHIH is released to inhibit the release of GH
26
where is the thyroid gland located?
sits on top of the cartilage of the trachea
27
where is the parathyroid hormone located?
imbedded in the thyroid, located int he back of the thyroid
28
What is this imaging showing?
thyroid follicle cells
29
a classic __________ feedback loop controls the regulation of thyroid hormone levels
negative
30
increased levels of ____ and ____ inhibits TRH and TSH
T3 and T4
31
_______ is required for synthesis of T3 and T4. a deficiency in it impairs ability to synthesize the hormones leading to severe disorders like goiter.
iodine
32
what disease is this: thyroglobulin accumulates in the thyroid gland follicles increasing the deposit of colloids increasing the overall size of the thyroid gland
goiter
33
what is hyperthyroidism?
the thyroid gland produces too much thyroid hormone (T3 and T4). This increases basal metabolic rate making people look very thin and shaky.
34
what is hypothyroidism?
the thyroid gland does not produce enough thyroid hormone (T3 and T4). This decreases basal metabolic rate causing weight gain due to stored energy.
35
what hormone does calcitonin regulate?
it regulates the parathyroid hormone
36
how does calcitonin remove Ca2+ from the blood?
- inhibits osteoclasts
- stimulates osteoblasts
- reduces Ca absorption from gut
- increase Ca lass via urine
37
what class of hormones is T4 and T3?
amine hormones
38
how many iodines does T4 have?
4
39
how many iodines have T3 have?
3
40
which one is more secreted: T3 or T4?
T4
41
which thyroid hormone is a pro hormone?
T4
42
which thyroid hormone is considered biologically active?
T3
43
how are T3 and T4 made?
thyroglobulin is synthesized in the follicular cells of the thyroid gland and is secreted into the colloid in the lumen . elsewhere in these cells , iodine , which is required to synthesize thyroid hormones , is taken up by membrane transporters. it is then oxidized to yield its active form bound to tyrosine residues of the protein in thyroglobulin. This forms MIT and DIT which combine to form T3 and T4 precursors. transported these precursors are then endocytosed, resulting in vesicles that combine w/ lysosome where it forms mature thyroid hormones
44
what is combined to make T3?
1 MIT and 1 DIT
45
what is combined to make T4?
2 DIT molecules
46
thyroid hormone binding protein in the thyroid gland
thyroglobulin
47
thyroid hormone binding proteins in the blood
- thyroxine-binding globulin (TBG - 75%)
- transthyretin (TTR - 15%)
- albumin (10%)
48
formation of MIT and DIT is catalyzed by ________
TPO - thyroid peroxidase
49
formation of T3 at tissue level is catalyzed by ____________
deiodinases
50
deiodination
a metabolic pathway that regulates the levels of thyroid hormones (T3 and T4) in the body
51
rT3 - reverse triiodothyronine
about 1% of thyroid hormone released, it is metabolically inactive because the "wrong" iodine is cleaved off, its purpose is that it slows down metabolism to conserve energy
52
what gland does this histology image show?
parathyroid gland
53
what are the two types of cells in a parathyroid gland?
- oxyphil
- chief / parathyroid cells
54
what is the purpose of the parathyroid hormone?
increase blood Ca levels when they drop too low
55
the parathyroid hormone produces ___________ to reduce Ca2+ when Ca2+ is too high
calcitonin
56
what two mechanisms are used to constantly maintain blood calcium concentration?
- parathyroid hormone
- calcitonin
57
what are the two parts of the adrenal gland?
- cortex
- medulla
58
what class of hormones does the adrenal cortex produce?
steroid hormones
59
what class of hormones does the adrenal medulla produce?
amine hormones
60
what are the 3 layers of the adrenal glands cortex? what hormones do they make?
- outer layer = MINERALcorticoids
- middle layer = GLUCOcorticoids
- inner layer = androgens
61
what is the purpose of mineralocorticoids?
involved in homeostasis of minerals and water
62
what is the purpose of glucocorticoids?
regulation of glucose metabolism, inflammation, immune function, and stress
63
what hormones are produced by the adrenal glands medulla?
norepinephrine and epinephrine
64
what is a hormone axes?
a hormonal cascade of endocrine pathways that respond to specific stimuli and/or negative feedback loops involving the hypothalamus anterior pituitary gland and target organs/cells (a regulation of the system)
65
hormone axes are generally ___________ feedback loops
negative
66
HPG axes
hypothalamus pituitary gonad
67
HPT axes
hypothalamus pituitary thyroid
68
what is the half-life of a hormone?
the time required for its concentration to decrease to half of its initial concentration
69
what does t 1/2 stand for?
half-life hormone
70
how are hormones removed from the body?
clearance and modification
71
a hormones half-life is inversely related to its metabolic ___________ rate
clearance
72
if a hormone is cleared slowly is has a _________ half life, if a hormone is cleared quickly is has a ________ half life
longer; shorter
73
afferent
the process of carrying signals to the nervous system
74
efferent
the process of carrying signals away from the nervous system
75
what are the 5 modes of cell-cell communication?
- endocrine
- autocrine
- paracrine
- juxtacrine
- intracrine
76
endocrine cell-cell communication
hormone signaling, enters the bloodstream
77
autocrine cell-cell communication
cell SECRETES signal and it then detects and responds to itself
78
paracrine cell-cell communication
cells communicating with the neighbor cell, signal diffuses in the extracellular fluid to be detected by the neighboring cell
79
juxtacrine cell-cell communication
cells communicating with the neighbor cell, signal diffuses in the extracellular fluid to be detected by the neighboring cell
80
intracrine cell-cell communication
is NOT secreted, signal is produced and detected in the cell
81
what color is hemoxylin? what does it bind to?
- purple
- basophils
82
what color is eosin? what does it bind to?
- pink
- acid
83
what is a chromophore?
NO stain
84
what are the three types of staining in histology?
- acidophils
- basophils
- chromophobes
85
lactotrophs make ________
prolactin
86
somatotrophs make _______
GH (somatotropin)
87
what hormones does the posterior pituitary secrete?
- antidiuretic hormone (ADH)
- oxytocin
88
oxytocin effect
causes uterine contractions, cervical dilation, causes milk letdown, and the love drug
89
oxytocin receptors in the uterus are _____ until it is near parturition, then they will ______ during parturition. the fetus pushes against the cervix stimulating the release of oxytocin from the pituitary stimulating contractions of the myometrium.
low; increase
90
if lactation and pregnancy occurred at the same time milk would be released but so would the conceptus. how does the body prevent this from happening?
oxytocin receptors are inactivated during pregnancy
91
what is the half life of oxytocin?
about 4 minutes, it is a short (acute) signal
92
what is Pitocin?
a synthetic form of oxytocin, used to induce labor
93
what is the effect of antidiuretic hormone?
stimulates water retention in the kidneys (less water excreted in urine)
94
pituitary endocrine disorders
- galactorrhea
- acromegaly
- gigantism/dwarfism
- cushing's disease
- diabetes insipidus
95
what type of disorder are the following caused by: galactorrhea, acromegaly, gigantism/dwarfism, cushing's disease, diabetes insipidus ?
pituitary endocrine disorders
96
acromegaly
too much growth hormone as an ADULT, they grow out causing large hands, big noses, a big jaw, etc.
97
gigantism
too much growth hormone as a CHILD
98
why does gigantism increase height while acromegaly does not?
gigantism affects children by making them grow taller because their growth plates are not yet fused
99
thyroid endocrine disorders
- hyperthyroidism / graves disease
- hypothyroidism / hashimotos disease
100
what is the disorder that causes the following diseases: hyperthyroidism (graves disease) and hypothyroidism (hashimotos disease) ?
thyroid endocrine disorders
101
what is another name for hyperthyroidism?
graves disease
102
what is another name for hypothyroidism?
hashimotos disease
103
what is graves disease?
the autoimmune antibody thyroid-stimulating immunoglobulin (TSI) that mimics TSH causing the thyroid gland to become overactive, leading to hyperthyroidism, and can also cause eye problems, known as Graves' ophthalmopathy
104
what is hashimotos disease?
an autoimmune disorder where the body's immune system mistakenly attacks the thyroid gland, leading to an underactive thyroid (hypothyroidism) and a reduced production of thyroid hormones
105
what is the name of the outer layer of the adrenal cortex zone? what class of hormones does it produce?
- zona glomerulosa
- mineralocorticoids
106
what is the name of the middle layer of the adrenal cortex zone? what class of hormones does it produce?
- zona fasciculata
- glucocorticoids
107
what is the name of the inner layer of the adrenal cortex zone? what class of hormones does it produce?
- zona reticularis
- androgens
108
what is general adaption syndrome (GAS)?
the body's physiological response to stress, occurring in three stages: alarm, resistance, and exhaustion.
109
what are the three stages of the general adaption syndrome?
1. alarm reaction
2. stage of resistance
3. stage of exhaustion
110
what is the first stage of general adaption syndrome?
alarm reaction, it is the fight or flight, short term
111
what is the second stage of general adaption syndrome?
stage of resistance, the body tries to adapt to the stressor
112
what is the third stage of general adaption syndrome?
stage of exhaustion, leading to health problems including depression, immune suppression, weight gain, etc.
113
what does RAAS stand for?
renin-angiotensin-aldosterone system
114
what is the purpose of RAAS?
to increase blood pressure (vasoconstriction and reabsorption in the kidneys)
115
describe the RAAS from start to finish
if there is a drop in blood pressure and fluid volume the kidney will produce renin which will activate angiotensinogen produced by the liver to produce angiotensin 1 which is further activates by ACE (which is produced by the lungs) to produce angiotensin 2. angiotensin 2 targets the blood vessels stimulating vasoconstriction and the adrenal gland which will then produce aldosterone which targets the kidney for reabsorption.
116
in RAAS, what hormone does the kidney produce?
renin
117
in RAAS, what hormone does the liver produce?
angiotensinogen
118
in RAAS, what hormone does the lungs produce?
ACE
119
in RAAS, what hormone does the adrenal gland produce?
aldosterone
120
what is galactorrhea?
hyperprolactinemia (excess prolactin produced), a condition where a person experiences milk production from their breasts outside of pregnancy or breastfeeding
121
what is cushings disease?
too much cortisol (glucocorticoid) due to an overproduction of ACTH
122
what is diabetes insipidus?
a rare disorder that affects the body's ability to regulate water balance, leading to excessive thirst and urination
123
what disease causes excessive urination (polyuria), light colored urine, and constant feeling of thirst (polydipsia)?
diabetes insipidus
124
what are the 4 types of diabetes insipidus?
- central
- nephrogenic
- dipsogenic
- gestational
125
central diabetes insipidus
caused by the brain, due to the lack of ADH, this can be due to injury or disease or autoimmune or genetic
126
nephrogenic diabetes insipidus
an issue in the kidney due to no response to ADH, this can be due to some meds, UT block or genetics
127
dipsogenic diabetes insipidus
caused by drinking too much
128
gestational diabetes insipidus
placenta makes too much enzyme that breaks down ADH
129
what does the pineal gland respond to?
light/darkness
130
what are circadian rhythms?
- biological clock
- photoperiod
131
what hormone does the pineal gland secrete? what class of hormone is it?
- melatonin
- amine hormone
132
light _______ (inhibits/stimulates) melatonin production and is _________ (lower/elevated) in the dark or low light
inhibits; elevated
133
what is the type of cell that produces melatonin in the pineal gland?
pinealocytes
134
what hormone is most present during the follicular phase?
estrogen
135
what hormone is most present during the luteal phase?
progesterone
136
what does the LH surge cause?
ovulation and lutenization
137
what are the 4 types of pancreatic inslets in the endocrine pancreas?
- alpha cells
- beta cells
- delta cells
- PP cells
138
what type of hormone do alpha cells produce?
glucagon
139
what type of hormone do beta cells produce?
insulin
140
what type of hormone do delta cells produce?
somatostatin
141
what type of hormone do PP cells produce?
pancreatic polypeptide hormone
142
what are the types of pancreatic inslets that regulate blood glucose?
- alpha cells (glucagon)
- beta cells (insulin)
143
what kind of cells make up the exocrine portion on the pancreas?
acinar cells
144
what is the average blood glucose? how does a ruminants blood glucose differ?
- 70-110 mg/dL
- ruminants have a much lower blood glucose because they do not absorb glucose in the small intestine
145
_________ is released from beta cells to promote the reduction of blood glucose
insulin
146
_________ is released from alpha cells to promote blood glucose levels
glucagon
147
label these parts of the pancreas
148
beta cells that secrete insulin also secrete _________ which is released with insulin
serotonin
149
what nerve is the connection of brain and the stomach?
the vagus nerve
150
type 1 diabetes mellitus
autoimmune disease that attacks beta cells so the source of insulin is lost
151
type 2 diabetes mellitus
acquired, adult onset, insulin resistance because the beta cells keep secreting insulin and they become exhausted
152
what is IGT?
impaired glucose tolerance
153
which is the normal response? which one is the diabetes response?
the left is normal, the right has the delay
154
what is the ominous octet?
eight key pathophysiological defects that contribute to the development and progression of type 2 diabetes mellitus
155
what are the 7 organs that are apart of the ominous octet?
liver, muscles, brain, adipose, kidneys, gi tract, and pancreas
156
in the pancreas, what cells produce many digestive enzymes and zymogens?
acinar cells (exocrine glands)
157
what are incretins?
- insulin secretions (hormones that act on the pancreas to secrete insulin)
- GIP and GLP-1
158
what stimulates incretins release?
they are released in response to nutrient ingestion
159
GLP-1
- glucagon like peptide 1
- stimulates insulin secretion
160
what hormones are incretins?
- GLP-1
- GIP
161
GIP name. What does it stimulate? What is it triggered by?
- gastric inhibitory peptide
- stimulate insulin secretion
- triggered by glucose
162
what effect does GLP-1 have?
- Stimulating the pancreas to release insulin
- Suppressing the release of glucagon, another hormone that raises blood sugar
- Slowing down gastric emptying
- Reducing appetite
163
what effect does GIP have?
suppress gastric motility and acid secretion (slow rate of passage and slow digestion)
164
what is segmaglutide the generic name for and what does it mimic?
- ozempic and wegovy
- mimics GLP-1
165
what brand name drug is approved for type 2 diabetes but NOT approved for weight loss use?
ozempic
166
what brand name drug is approved for weight loss and is only a once a week injection?
wegovy
167
what is mounjaro and zepbound?
to treat obesity or overweight people with health conditions, mimics GIP and GLP-1
168
what is the somatomedin hypothesis?
mediates the effects of somatotropin (GH)
169
what are the reflexes that cause the stimulation of endocrine glands?
- chemical or nervous signals
- osmoreceptors
- thermoreceptors
170
what are beta endorphins?
opioid receptors (make you feel good), they are associated with hunger, thrill, pain, maternal care, sexual behavior, and reward cognition
171
myoepithelial cell contraction is triggered by ________ which assists in milk meltdown
oxytocin
172
what are the central and peripheral inhibition of milk letdown?
- central: block release of OT
- peripheral: block binding at target cells
173
to achieve peripheral inhibition _________ which causes vasoconstriction blocks off blood flow to the mammary glands
epinephrine
174
where are myoepithelial cells located?
- salivary glands
- breast
- lacrimal glands
- sweat glands
- tracheobronchial glands
175
oxytocin and vasopressin (ADH) have very similar structures but how are they different?
they have completely different functions, for example oxytocin decreases aggression and anxiety which vasopressin increases them
176
what is MSH? what secretes it?
- melanocyte stimulating hormone
- secreted by pituitary gland
177
different levels of MSH are NOT the major cause of variation of skin color, it is the variation in their hormone __________, so they don't respond so they do not make melanin
receptors
178
how do receptors work?
protein that bings a ligand with high affinity and low capacity; must be saturable
179
the target cells of a hormone must express a specific _________ for it
receptor
180
hormone-receptor interaction is defined by the ___________ constant also known as the ____________ constant
equilibrium; dissociation (Kd)
181
Ka
association constant; how it goes on
182
Kd
dissociation constant; how it comes off
183
what are hormone binding proteins?
they are water soluble globular proteins in the plasma that can carry proteins through the blood
184
what are the hormone binding proteins CBG and SHBG used for?
steroid hormones
185
what are the hormone binding proteins TBR, TTR, and albumin used for?
thyroid hormones
186
what is insulin triggered by?
- food in the intestine (GIP released)
- blood glucose
187
main target cells for insulin
- skeletal muscle
- adipocytes
188
what is the action of insulin?
insulin activates a tyrosine kinase receptor, triggering the phosphorylation of substrates the movement of intracellular vesicles containing glucose transporters to the
cell membrane
189
GLUTS move glucose by _________ diffusion
facilitated
190
how is glucose stored in animals?
glycogen
191
how is glucose stored in plants?
- cellulose
- starch (amylose and amylopectin)
192
what glucose storage in animals has alpha 1,4 main chain and alpha 1,6 branch glycosidic bonds?
glycogen
193
what glucose storage in plants have alpha 1,4 main chain and alpha 1,6 branch glycosidic bonds?
amylopectin
194
what glucose storage in plants has alpha 1,4 glycosidic bonds?
amylose
195
what glucose storage in plants has beta 1,4 glycosidic bonds?
cellulose
196
does insulin stimulate or inhibit glycolysis?
stimulates
197
does insulin stimulate or inhibit glucogenesis?
stimulates
198
does insulin stimulate or inhibit lipogenesis?
stimulates
199
does insulin stimulate or inhibit protein synthesis?
stimulates
200
does insulin stimulate or inhibit glucogenolysis?
inhibits
201
does insulin stimulate or inhibit gluconeogenesis?
inhibits
202
functions of the digestive system
- digestion of food
- absorption of nutrients
- intake food
- excrete waste
- sensory organ
- endocrin/efffector organ
- immune defense
- immune defense
- microbiome
203
what is the hepatic portal system?
allows most of the absorbed nutrients to first go to the liver
204
what are the 4 layers of the gi tract?
- mucosa
- submucosa
- muscularis
- serosa
205
what are the three components of the mucosa layer?
- lining epithelium
- lamina propria
- muscularis mucosal
206
what are the 2 layers of the muscularis?
- inner circular smooth muscle
- outer longitudinal smooth muscle
207
what is the purpose of epithelial lining?
- protection (stratified squamous)
- absorption (single layer columnar or cuboidal cells)
- lubrication (goblet cells)
- hormone secretion (enteroendocrine cells)
208
what makes up the lamina propria?
- loose CT
- blood and lymph vessels (MALT)
209
MALT
mucosa associated lymphoid tissue
210
what are villi?
finger like projections, lots in the mucosa to increase surface area and make it distensible (to stretch)
211
what makes up the submucosa?
- dense irregular connective tissue
- blood and lymph vessels
- submucosal glands
- submucosal plexus
212
which layer is the submucosal plexus located in?
submucosa
213
what is serosa made up of? where is it located?
- loose connective tube
- only in the abdominal cavity
214
instead of serosa, the mouth, pharynx, and esophagus have ____________, a dense collagen attachment
adventitia
215
what are the differences of the small and large intestine showcased in this image?
- the small intestine has much greater depth in the mucosa for digestion and absorption
- the large intestine does NOT have villi, but they have crypts for passage, lubrication, and water
216
label this image
- mucosa
- submucosa
- muscularis
- serosa
217
what are the 2 broad categories of the GIT nerve supply?
intrinsic and extrinsic
218
what is the intrinsic nervous system?
- enteric neurons
- they are independent from the rest of the system
219
what are examples of enteric neurons?
- myenteric plexus
- submucosal plexus
220
where is the myenteric plexus located?
in the muscularis
221
where is the submucosal plexus located?
in submucosa
222
what is the purpose of the myenteric plexus?
for motility and peristalsis
223
what is the purpose of the submucosal plexus?
it regulates digestive secretions, it detects the presence of food and knows what has been consumed to secrete what it needs
224
what nerve supply ensures that the gut will continue to move after death because it has its own central nervous system?
interneurons
225
what is the extrinsic nervous system?
the autonomic system (classical CNS) with sympathetic and parasympathetic nervous systems
226
what is the purpose of the sympathetic nervous system?
fight and flight (inhibits they intrinsic neurons)
227
what is the purpose of the parasympathetic nervous system?
rest and digest (stimulates the intrinsic neurons)
228
what nutrients does the GIT blood supply transport?
proteins (amino acids) and carbohydrates
229
how are lipids transported from the GIT?
by lacteals (lymph vessels)
230
what is the hepatic portal system?
veins carry the nutrients to the liver so it is able to process and store them
231
why would someone be cold after a meal?
during rest and digest, 25% of the blood flow goes to the gut
232
what is the GIT peritoneum? what is it made up of?
the sac around/lining the gut. it is a broad serous membrane sac. made up of stratified squamous epithelium and connective tissue.
233
what are the two layers of the GIT peritoneum?
- parietal
- visceral
234
what is the parietal peritoneum?
lines abdominal walls (keeps the organs together)
235
what is the visceral peritoneum?
surrounds the gut organs (separates the organs)
236
what is the greater omentum?
fat deposition in the visceral layer of the peritoneum
237
what are the 6 fundamental activities of the GIT?
1. ingestion
2. propulsion
3. mechanical/physical digestion
4. chemical digestion
5. absorption
6. defecation
238
what occurs during ingestion?
biting, chewing, saliva
239
what occurs during propulsion?
swallowing, peristalsis (muscularis)
240
what occurs during mechanical/physical digestion?
increases surface area, mastication, insalivation
241
what occurs during chemical digestion?
enzymes, acids, salts; reduce what we consume and make it into the nutrients that can be absorbed
242
what is chyme?
soup of digesta, contains acid and enzymes
243
what is segmentation?
peristalsis of digesta, moving back and forth in the GIT
244
what are long reflexes?
extrinsic neurons (they are overriding)
245
what are short reflexes?
intrinsic neurons (local)
246
what is a plexus?
a network of nerves, blood, or lymph vessels
247
oral cavity / buccal cavity
the mouth
248
labia
lips
249
gingivae
gums
250
oral vestibule
space between the cheeks and teeth
251
fauces
the throat, the opening between the oral cavity and oropharynx
252
palate
roof of the mouth
253
hard palate vs soft palate
- hard palate is the bony part that separates the oral cavity and oropharynx
- soft palate is muscular posterior and aids in swallowing
254
uvula functions
block trachea during swallowing, secrete saliva, speech, airflow, gag reflex
255
what are the tonsils made up of?
lymphoid tissue
256
what is a frenulum? what is a superior labial frenulum, inferior labial frenulum, and lingual frenulum?
- frenulum = reale like tissue that connects
- superior labial frenulum = connects upper lip and gum
- inferior labial frenulum = connects bottom lip and gum
- lingual frenulum = connects tounge to mouth
257
what is the epiglottis function?
during swallowing the epiglottis folds down over the larynx preventing food and liquids from entering the trachea
258
the tongue is covered in ________ that are often called the taste buds
papillae
259
what are the 3 major salivary glands?
- parotid
- sublingual
- submandibular
260
what are the functions of the salivary glands?
- lubricates
- buffers acids
- enzymes
- moistens
261
what causes dental caries?
cavities are caused by eating sugar, the bacteria will eat the sugar and produce and acid, the acid can demineralize/break down the teeth causing the dental caries / cavities
262
what are sialolithiasis?
salivary stones, they are calcium concretions that block saliva from leaving the gland which is painful
263
what can help remove sialolithiasis?
sucking on citrus fruits which increases salivation to remove the stones
264
what are deciduous teeth?
baby teeth, teeth that are meant to be lost or shed over time
265
what are the 4 types of permanent teeth?
- incisors
- cuspids (canines)
- bicuspids (premolars)
- tricuspids (molars)
266
what is a crown on a tooth?
the top section of the tooth
267
what is the root of the tooth? what does it contain?
- the base, within the gum
- contains the pulp cavity
268
what does the pulp cavity contain?
it contains the blood vessels and nerves
269
what is dentin?
hard, mineralized tissue that forms the bulk of the tooth structure. it surrounds the pulp cavity and is located beneath the enamel.
270
what is the hardest substance in the body?
enamel
271
what is the hard substance that covers the tooth?
enamel
272
what is cementum?
glues the enamel to the dentin
273
the tongue is a _______ that helps with the movements and functions of the tongue
muscle
274
what are the 2 types of muscles in the gi tract?
- extrinsic muscles
- intrinsic muscles
275
what are the 3 parts of the pharynx?
- nasopharynx
- oropharynx
- laryngopharynx
276
what is the nasopharynx?
the connection to the nasal cavity, gives the ability to breath and speak
277
what is the oropharynx?
the connection to the oral cavity that assists in breathing and digestion
278
what is the laryngopharynx?
the connection to the larynx which assists in breathing and digestion
279
what is the purpose of the pharynx?
coordinates swallowing, breathing and digestion
280
what is the connector between the mouth and stomach?
esophagus
281
what is the upper esophageal sphincter? what type of muscle is it composed of?
controls the movement of food from the pharynx to the esophagus. skeletal and smooth muscle.
282
what is the lower esophageal (cardiac) sphincter? what type of muscle is it composed of?
controls the movement of food from the esophagus to the stomach. smooth muscles only.
283
what is heartburn?
stomach acid in the esophagus
284
what part of the diaphragm allows the esophagus to move through?
esophageal hiatus
285
what is deglutition?
swallowing
286
what are the three phases of deglutition?
1. voluntary
2. pharyngeal phase
3. esophageal
287
what phases of deglutition are involuntary?
2. pharyngeal phase
3. esophageal
288
describe the voluntary phase of swallowing?
you control when you swallow food
289
describe the pharyngeal phase of swallowing?
stimulation of the oropharynx receptors that cause the uvula and soft palate to close off the nasopharynx and the laryngeal muscles close off the trachea
290
describe the esophageal phase of swallowing?
food enters the esophagus, triggers peristalsis and mucus, the cardiac sphincter relaxes
291
what are the 4 regions of the stomach?
1. cardia
2. fundus
3. body
4. pylorus
292
what is the main function of the stomach?
mechanical and chemical digestion
293
what is a pyloric sphincter?
connects the stomach to the duodenum
294
what is the purpose of the rugae / folds in the stomach?
increase surface area and to have distention
295
what is the greater curvature and lesser curvature of the stomach attached to?
the greater momentum and lesser omentum
296
what is the purpose of the inner oblique smooth muscle?
ability to vigorously churn and mix food
297
what are the cells of the gastric glands?
- parietal cells
- chief cells
- mucous neck cells
- enteroendocrine cells
298
what do parietal cells secrete?
- HCl
- intrinsic factor
299
what is the purpose of HCl in the stomach?
lowers stomach pH to 1.5-3.5 and assists in acid digestion as it activates pepsin
300
what is the purpose of the intrinsic factor?
it is a glycoprotein required for vitamin B12 absorption in the small intestine
301
what do chief cells secrete?
pepsinogen
302
what do mucous neck cells secrete?
mucus
303
what do enteroendocrine cells secrete?
hormones (gastrin, ghrelin, somatostatin)
304
gastrin: secreted by, stimulated by, target/action
- G cells
- peptides / AA
- movements of digesta along the GIT
305
ghrelin: secreted by, stimulated by, target/action
- mucosa
- fasting
- hypothalamus / hunger
306
somatostatin: secreted by, stimulated by, target/action
- mucosa and duodenum
- food, sympathetic stimulation
- stomach (decrease motility, secretions, emptying), pancreas (decrease secretions), small intestine (decrease absorption and blood flow)
.
307
3 phases of gastric secretion
1. cephalic
2. gastric
3. intestinal
308
what is the cephalic phase of gastric secretion?
the reflex phase that occurs in the brain, there is NO food in the stomach yet
309
what is the gastric phase of gastric secretion?
occurs in the stomach and lasts 3-4 hours, as food enters the stomach stretches and stimulates secretions and contractions
310
what is the intestinal phase of gastric secretion? what are the 2 parts?
- excitatory (chyme is moved into the duodenum stimulating enteric gastrin which increases the flow of gastric juice)
- inhibitory (the duodenum is full and inhibits secretin and closes the pyloric sphincter)
311
what are the components of the gastric mucosal barrier?
1. mucus
2. bicarbonate
3. tight junctions
312
what is the purpose of the gastric mucosal barrier?
the mucus-bicarbonate barrier have bicarbonate (HCO3-) to neutralize the acid protecting cells by making a neutral pH
313
what occurs during the mechanical digestive functions of the stomach?
- mixing waves
- pylorus filtering
- gastric emptying
314
what does it mean that the gastric emptying is rhythmic? what is it regulated by?
- a little bit is moves through at a time, a metered dose
- regulated by the duodenum and stomach
315
what occurs during the chemical digestive functions of the stomach?
- lipid digestion
- protein digestion
- intrinsic factor
316
what nutrient slows down the stomach emptying?
the digestion of lipids
317
how long foes full digestion take?
24-72 hours
318
what is pernicious anemia?
vitamin B12 deficiency, a chronic illness caused by impaired absorption of vitamin B12 because of a lack of intrinsic factor in gastric secretions
319
what is the treatment for pernicious anemia?
a vitamin B12 shot once a month
320
vitamin B12 is required for ______ synthesis, causing organs with rapid cell turnover to be impacted if there is a deficiency of B12
DNA
321
pernicious anemia is an example of ____________ anemia, where megaloblasts are large nucleated RBC precursors with non condensed chromatin
megaloblastic
322
what is the primary digestive and absorptive organ?
small intestine
323
what part of the digestive system is the longest but has the smallest diameter?
the small intestine
324
what are the 3 main anatomical features that contribute to the large surface area of the small intestine?
1. plicae circulares
2. villi
3. microvilli
325
what are the 3 parts of the small intestine in order from beginning to end?
1. duodenum
2. jejunum
3. ileum
326
what part of the small intestine contains the pyloric sphincter?
duodenum
327
what is the pyloric sphincter?
connects the stomach to the small intestine
328
the duodenum makes a C-shape around the __________, an accessory organ of the GIT
pancreas
329
what is the ampulla of Vater (hepatopancreatic ampulla)?
it is where common bile duct and pancreatic duct join dump content
330
what is the sphincter of Oddi (hepatopancreatic sphincter)?
it regulates when the ampulla of Vater (hepatopancreatic ampulla) opens and closes to release its contents
331
the exocrine pancreas _________ cells secrete digestive enzymes
acinar
332
what ducts form the common bile duct?
common hepatic duct + cystic duct
333
what ducts empty into the duodenum?
common bile duct + pancreatic duct
334
bile is made in the ________ and flows the the common hepatic duct and cystic duct to the _________ where it is stored
liver; gallbladder
335
when food is being digested, bile is released from the gallbladder and flows through the ____________ ______ duct and pancreas into the small intestine
common bile
336
what is the purpose of the jejunum?
absorption (little digestion)
337
what is the last and longest section of the small intestine that is which with many folds?
ileum
338
what is the ileocecal sphincter?
where the ileum joins the cecum to connect the small intestine to the large intestine
339
what are the 3 unique features of the mucosa and submucosa for the small intestine to increase surface area and have the most absorption?
1. circular folds/plicae circularis
2. villi
3. microvilli
340
where are circular folds / plicae circularis located and what is the purpose?
- end neat mid-ileum
- forms ridges which cause the chyme to spiral through
341
what is contained within the villi?
absorptive cells including enterocytes, arterioles and venules, lacteals
342
what structure is considered the brush border?
microvilli
343
what are the two types of intestinal glands?
- crypts of lieberkuhn
- Brunner's glands (duodenal glands)
344
what cell has the function of: digestion and absorption of nutrients in chyme
absorptive cell
345
what cell has the function of: secretion of mucus
goblet cell
346
what cell has the function of: secretion of bactericidal enzyme lysozyme; phagocytosis
paneth
347
what cell has the function of: secretion of the hormone intestinal gastrin
G cells
348
what cell has the function of: secretion of the hormone CCK (cholecystokinin), which stimulates release of pancreatic juices and bile
I cells
349
what cell has the function of: secretion of the hormone glucose-dependent insulinotropic peptide (GIP), which stimulates the release of insulin
K cells
350
what cell has the function of: secretion of the hormone motilin, which accelerates gastric emptying, stimulates intestinal peristalsis, and stimulates the production of pepsin
M cells
351
what cell has the function of: secretion of the hormone secretin (stimulates brunners glands)
S cells
352
what is the purpose of segmentation?
separates chyme and then pushes it back together, mixing it and providing time for digestion and absorption
353
where is segmentation most rapid?
in the duodenum
354
the hormone _________ from the duodenum triggers the migration motility complexes (peristalsis)
motilin
355
what is the gastroileal reflex?
- digestion in eh stomach triggers segmentation
- gastrin stimulates ileal motility
356
the chemical digestion in the stomach will ________ the digestion of proteins and carbohydrates and _______ digestion of lipids
finish; most
357
why does lactose intolerance occur?
lactose draws water and when fermented int eh large intestine creates gas, so without lactase to break down lactose it causes diarrhea and gas
358
what are the segments of the large intestine?
- cecum (+appendix)
- colon
- rectum
- anus
359
which part of the GIT has the function to finish nutrient absorption, absorb water synthesize vitamins, forms feces, and defecation?
large intestine
360
what is the ileocecal valve?
connects the small intestine and large intestine
361
what are the 4 parts of the colon, in order?
1. ascending
2. transverse
3. descending
4. sigmoid
362
what is the pneumonic to remember the sections of the color in order?
ATDS: after this defecate soon
- ascending
- transverse
- descending
- sigmoid
363
in the rectum there are 3 ________ _______ to help separate gas from feces
lateral bends
364
what is the difference between the internal anal sphincter and external anal sphincter?
- internal anal sphincter has smooth muscle so it is involuntary
- external anal sphincter has skeletal muscle so it is voluntary
365
what is the type of epithelium located in the anal canal? why?
stratified squamous epithelium, for protection
366
what are 3 unique features of the large intestine?
- teniae coil
- haustra
- epiploic appendages
367
what are teniae coil of the large intestine?
three bands of smooth muscle to keep it bunched up
368
what are haustra of the large intestine?
pouches that are called the feces formation chamber
369
what are the epiploic appendages of the large intestine?
fat filled sacs with unknown function
370
what is the image on the left vs the image on the right?
- left: small intestine
- right: large intestine
371
what features make these two histologies distinguishable?
- small intestine has more enzyme secreting cells that allow the entry of bile and pancreatic juice. there is an increase in surface area with plicae, villi and microvilli.
- the large intestine has a lot more intestinal glands, enterocytes (for absorption), and global cells (that produce mucus)
372
__________ cells open the tight junctions between epithelial cells and extend probes into the lumen of the large intestine to evaluate the microbial antigens
dendritic
373
the dendritic cells with antigens then travel to neighboring lymphoid follicles in the mucosa where ___ cells inspect for antigens
T cells
374
what are the three types of movements during mechanical digestion of the large intestine?
- haustral contaction
- peristalsis
- mass movement
375
gastrocolic reflex
when stretch in the stomach and chemicals in the small intestine stimulate colon motility
376
what are the three accessory organs in digestion?
- liver
- pancreas
- gallbladder
377
what is the livers digestive function?
produces bile
378
what is the gall bladders digestive function?
stores/concentrates and releases bile
379
what is the pancreases digestive function?
produces pancreatic joule (which contains digestive enzymes and bicarbonate)
380
what is the portal hepatis (hepatic portal)?
a vein that carries nutrients from the small intestine straight to the liver
381
what 3 structures make the portal triad of the liver?
- bile duct
- portal vein
- hepatic artery
382
what are the 3 main components the make up the liver?
- hepatocytes
- bile canaliculi
- hepatic sinusoids
383
what is the main cell in the liver?
hepatocytes
384
what is the main function of a hepatocyte?
produce bile
385
what is the purpose of the bile canaliculi in the liver?
they are canals that carry the bile produced by hepatocytes to the bile duct
386
what is purpose of the hepatic sinusoids?
the liver's unique microvascular structure, is to facilitate the exchange of nutrients, oxygen, and other substances between the blood and the hepatocytes
387
kupffer cells
specialized macrophages located in the liver (immune cells)
388
stellate cells
in the liver they accumulate fat and vitamin A
389
what is the space of disse
in the liver, it is the space between the hepatocytes and sinusoidal endothelial cells
390
what type of capillary is found in the liver?
sinusoidal capillaries
391
the liver receives oxygenated blood from the ________ _____ and nutrient rich deoxygenated blood from the ______ _______ _____
hepatic artery; hepatic portal vein
392
what is fatty liver disease?
hepatocytes in the liver accumulate a lot of lipids making it difficult for the cells to function
393
bile production increases when fatty chyme enters the duodenum and stimulates the secretion of the gut hormone __________
secretin
394
what are chylomicrons?
large, triglyceride-rich lipoproteins produced in the small intestine to transport dietary fats and cholesterol from the intestines to the liver and other tissues via the bloodstream
395
describe the central vein in the liver?
a vein located at the center of each hepatic lobule in the liver, collecting blood from the sinusoids and draining it into the hepatic veins, which ultimately lead to the inferior vena cava.
396
pancreatic ______ cells secrete hormones
islets
397
pancreatic ______ cells secrete digestive enzymes
acinar
398
the gallbladder stores and concentrates bile by...
absorbing water
399
for carbohydrate digestion, what can be absorbed?
ONLY monosaccharides (glucose, galactose, fructose)
400
for protein digestion, what can be absorbed?
single AA, dipeptides and tripeptides
401
for triglycerides what can be absorbed?
monoacylglycerides, glycerol and free fatty acids
402
for nucleic acids what can be absorbed?
pentose sugars, phosphates and nitrogenous bases
