Module 2 Flashcards
1
Q
What is an A1C test?
A
- reflects the average blood glucose values of previous 2-3 mo
2
Q
How does an A1C work?
A
- measures the % of Hb “coated” with glucose
3
Q
What are A1C levels?
A
- normal < 5.7%
- diabetes < or = 6.5%
4
Q
Where does the pancreas secrete into?
A
- duodenum
5
Q
T/F: The pancreas has endocrine but not exocrine function.
A
- False, both endocrine and exocrine
6
Q
What area of the pancreas is relevant to its endocrine function?
A
- Islets of Langerhans
7
Q
What are the three cell types of the Islets of Langerhas?
A
- alpha
- beta
- delta
8
Q
What do alpha cells of the Islets of Langerhans secrete?
A
- glucagon
9
Q
What do beta cells of the Islets of Langerhans secrete?
A
- insulin
co-secretion of amylin
10
Q
What do delta cells of the Islets of Langerhans secrete?
A
- somatostatin (technically not the same as the hypothalamic somatostatin but still think inhibitor)
11
Q
What is the function of glucagon?
A
- prevents hypoglycemia/mobilizes “metabolic fuels”
12
Q
How does glucagon achieve its function?
A
- increases blood glucose levels by mobilizing glucose and FFA
13
Q
What is the relationship of glucagon and insulin?
A
- opposite
- glucagon is antagonist to insulin
14
Q
T/F: Glucagon is a catabolic hormone.
A
- True
15
Q
What is the target tissue of glucagon?
A
- liver
- fat
- muscle
16
Q
What does glucagon do in the liver?
A
- glycogenolysis (breakdown of glycogen to glucose)
- glucogenesis (glucose formation)
17
Q
What does glucagon do in the fat?
A
- stimulates lipolysis
18
Q
What does glucagon do in the muscle?
A
- proteolysis
19
Q
What is proteolysis?
A
- breakdown for a.a. release but not efficient
20
Q
In response to _______, glucagon is trying to make “____”
A
- hypoglycemia
- fuel
21
Q
What does glucagon increase blood levels of in response to hypoglycemia?
A
- glucose
- FFA & ketones
- a.a.
22
Q
What is the precursor for glucose and ketone formation?
A
- FFA oxidation in the liver
23
Q
What are used as fuel by the CNS, heart, and body?
A
- ketones
24
Q
What does excess ketones (and glucose) blood levels lead to?
A
- acidosis (ketoacidosis)
25
What factors stimulate glucagon secretion from pancreas?
- hypoglycemia (major)
- exercise
- stress
- fasting
26
What factors inhibit glucagon secretion from pancreas?
- hyperglycemia
| - amylin
27
When is amylin secreted?
- with insulin during feeding
28
What is the function of amylin?
- suppress glucagon which leads to increased satiety/decreased appetite and inhibits GI mobility
- inhibits plasma glucose (tells glucose to stay in pancreas)
29
What is the function of insulin?
- prevents hyperglycemia
| - promotes "metabolic fuel" storage
30
**How does insulin make its functions?**
- decreases blood glucose levels by increasing uptake into cells
- decreases blood levels of [a.a.] and FFA/ketones
- decreases serum K+ levels by promoting uptake into cells
31
What two parts of the body DO NOT require insulin for glucose uptake?
- brain
| - RBC
32
Why are insulin and glucose administered for hyperkalemia?
- decreases serum K+ levels by promoting uptake into cells
33
What is the target tissues of insulin?
- liver
- muscle
- adipose tissue
34
What does insulin increase in the liver?
- glucose uptake
- form glycogen
- lipid/protein synthesis
35
What does insulin decrease in the liver?
- ketogenesis
| - glycogenolysis
36
What does insulin increase in the muscle?
- glucose uptake
- form glycogen
- a.a. uptake
- protein synthesis
37
What does insulin decrease in the muscle?
- glycogenolysis
38
What does insulin increase in the adipose?
- glucose uptake
- glucose to form glycerol phosphate
- fat storage
39
What does insulin decrease in the adipose?
- lipolysis
40
What factors stimulate insulin release from the pancreas?
- hyperglycemia (major)
- increased serum FFA & a.a. levels
- GI/digestive hormones
- parasympathetic stimulation of beta cells
41
What factors inhibit insulin release from the pancreas?
- hypoglycemia
- neg feedback loop
- sympathetic stimulation of beta cells
- prostaglandins (PGE2)
42
Describe obesity and its relationship with insulin regulation/Type II diabetes
- increased insulin will down-regulate receptors
- fewer receptors lead to glucose remaining elevated despite sufficient insulin
- elevated glucose down-regulates receptors
43
What is the result of type II diabetes?
- insulin resistance (decreased sensitivity)
44
What are the two types of diabetes mellitus?
- type I
| - type II
45
What are the three "poly's" of diabetes?
- polyuria (excessive urine production)
- polydipsia (excessive thirst)
- polyphagia (increased appetite)
46
What is DM type I?
- insulin insufficiency d/t destruction of beta cells
| - ? autoimmune
47
T/F: DM type I is not associated with obesity.
- True
48
What is the result of DM type I?
- hyperglycemia
- hyperlipidemia
- increased ketone bodies/ketoacidosis
- catabolic affect on muscle mass
49
What is a risk of hyperlipidemia?
- atherosclerosis from lipid deposits in blood vessels
50
What does metabolic acidosis lead to?
- increase [H+] ==> coma & death
51
What is insulin shock?
- reaction to hypoglycemia
52
What are causes of insulin shock?
- excessive insulin admin
- increased physical activity
- poor glucose monitoring
53
What is the treatment for insulin shock?
- bring glucose levels back up via oral or IV simple sugar or glucagon injection
54
What can improve DM type II?
- diet changes
| - exercise
55
What is OGTT?
- oral glucose tolerance test
56
What are the values for a fasting plasma glucose test?
- normal < 140mg/dL
| - diabetes > or = 200mg/dL
57
What are the values for OGTT?
- normal < 100 mg/dL
| - diabetes > or = 140mg/dL
58
What is seen on a thyroid function lab panel?
- TSH
- T4
- T3
59
What are the hormones of the thyroid gland?
- T4 (thyroxine)
- T3 (tri-iodothyronine)
- calcitonin
60
Where are T3 & T4 synthesized?
- follicle cells
61
Where are T3 & T4 stored?
- follicle cavities (colloid)
62
Are T3 & T4 hydrophilic or lipophilic?
- lipophilic
63
Describe the synthesis of T3 & T4
FOLLICLE CELL
- tyrosine synthesized into TGB precursor
- iodine pumped into cell
- TGB binds iodine
- TGB/I complex (aka T3/T4 with TGB) pumped into FOLLICLE CAVITY for storage
64
How is iodine pumped into the follicle cell?
- TSH sensitive iodine pump
| - captures 25% dietary iodine
65
Describe the secretion of T3 & T4
- TRH released from hypothalamus
- TRH stimulates ant. pit to release TSH
- TSH stimulates transport of T3/T4 back into follicle cell
- enzymes separate T3/T4 from TGB
- T3 & T4 diffuse into bloodstream
66
What is the percentage of T3 & T4 secreted into blood stream?
- 90% T4
- 10% T3
(T4 significantly more than T3)
67
How does T3/T4 circulate in the bloodstream and why?
- bound to carrier proteins
| - fat soluble
68
How much of circulating T3/T4 is free?
- 0.03%
69
How is free T3 & T4 excreted?
- kidneys
70
What can a free T3/T4 do that a protein bound T3/T4 cannot do?
- enter cell
| - protein bound must dissociate
71
____ has 1000x the affinity for receptor than ____, therefore ____ is much more potent.
- T3
- T4
- T3
72
Free (active) T4 has a ____ affinity for the receptor while free (actvite) T3 has a ____ affinity.
- weak
| - strong
73
What are the two pathways for T4 once it enters the cell?
- bind to receptor in cell nucleus
| - convert to T3 of rT3 in cytoplasm/membrane
74
What is the primary site of T4 to T3 conversion?
- liver
75
How is T2 produced?
- rT3 and any T3 not utilized
76
What is the stimuli for thyroid hormone release?
- metabolic demand
- TSH
- pregnancy (growth)
- gonadal and adrenocortical steroids (growth)
- extreme cold temp (stress/energy production)
- catecholamines (stress)
77
What inhibits thyroid hormone release?
- negative feedback from elevated TSH
- GHIH (somatostatin) (inhibits growth)
- DA (PIH) (inhibits growth)
78
What are the big picture functions of thyroid hormones?
- growth & development (critical for CNS development)
- control metabolism rate
THEREFORE: regulate/influence every organ of the body
79
What is affected in metabolism by thyroid hormones?
- increases BMR and O2 of the body
- increases BMR in all tissues except brain, spleen, testes
- temperature regulation of increased heat from increased BMR
80
What is affected in growth & development by thyroid hormones?
- stimulates GH release
| - CNS maturation is dependent
81
What could a clinical sign be of decreased thyroid function on the CNS?
- cognitive impairments
82
What is the target tissue of thyroid hormone?
- all cells except brain, gonads, and spleen
83
What is the general action of thyroid hormone?
- increased cellular respiration
| - elevated BMR --> increased demand for fuel --> glycogenolysis & gluconeogenesis ==> increased liver glucose production
84
What do thyroid hormones cause in the heart?
- increased CO & CO via increased sensitivity to sympathetic system/E
85
What do thyroid hormones cause in the vasculature?
- vasodilation
86
What do thyroid hormones cause in the pulmonary?
- increased resp. rate via stimulation of ventilation center in brainstem
87
What do thyroid hormones cause in the CNS?
STIMULATES:
- myelin/axonal growth and development
- sympathetic activity
88
What do thyroid hormones cause in the adipose?
- increased lipolysis (mobilize FFA for metabolic fuel)
89
What do thyroid hormones cause in the muscle?
- promote muscle protein growth/development synergistically with other growth hormones
90
What will excessive levels of thyroid hormones cause in the muscle?
- promote catabolic metabolism to provide fuel for increased BMR
91
What do thyroid hormones cause in the bone?
- promote bone growth/development synergisticaly with IGF-1/growth hormones
92
What do thyroid hormones cause in the liver?
- promote TG and cholesterol metabolism
| - regulate LDL homeostasis
93
What do thyroid hormones cause in the GI?
- maintain GI secretions
94
What do thyroid hormones cause in the pit. gland?
- inhibits TSH
- stimulates release of GH
- stimulates synthesis of pit hormones
95
What are the clinical symptoms of hyperthyroidism?
- goiter
- palpitations, HTN, increased pulse pressure, tachycardia, increased CO
- elevated RR
- hyperactive, fine tremor, increased "nervousness", increased sympathetic activity
- warm, moist skin (d/t elevated heat production from elevated BMR), excessive sweating, thin/fine hair
- wt loss: muscle wasting, proximal weakness, fat loss
- exophthalmos
- increased motility and BMs
96
What are two forms of symptoms that can produce exophthalmos associated with hyperthyroidism?
- sympathetic hyperactivity leading to wide open eyes
| - infiltrative changes (i.e. Graves dz)
97
What are the forms of hyperthyroidism?
- primary
| - secondary
98
What are the types of primary hyperthyroidism?
- endogenous
- iatrogenic
- "thyroid storm"
99
What is endogenous hyperthyroidism?
- excessive TSI (thyroid-stimulating immunoglobulins) bind to TSH receptors and stimulate T3/T4
- increased T3/T4 functions normally to negatively feedback and inhibit TSH
100
What will the labs look like for endogenous hyperthyroidism?
- elevated: TSI & T3/T4 (mostly T3)
| - decreased: *TSH* & TRH
101
What is an example of endogenous hyperthyroidism?
- Graves Dz
102
What is iatrogenic hyperthyroidism?
- excessive use of synthetic thyroixine
103
What is "Thyroid Storm"?
- rare but life threatening form of hyperthyroidism
104
What is secondary hyperthyroidism?
- continued secretion of TSH regardless of neg. feedback loop
105
What are the types of hypothyroidism?
- adult onset (primary)
| - congenital (secondary)
106
What is the most common cause of hypothyroidism?
- Hashimoto's thyroiditis (autoimmune)
107
What is hypothyroidism?
- malfunctioning thyroid which does not secrete T3/T4 in response to elevated TSH
108
What will the labs look like for primary/adult onset hypothyroidism?
- elevated *TSH*
| - decreased T3/T4 (mostly T4)
109
What happens to T4 when T3 and T4 are both low?
- converted to T3 as the body demands
110
What will the labs look like for secondary/congenital hypothyroidism?
- decreased TSH
- decreased T3/T4
"all are low"
111
Define goiter
- enlarged thyroid gland
112
What causes a goiter?
- elevated TSH attempting to stimulate the thyroid
113
T/F: A goiter always predicts abnormal thyroid function.
- False
114
What is Grave's disease?
- hyperthyroidism
| - enlargement d/t immunoglobulins (TSI) stimulating thyroid gland to produce T3/T4
115
What is Hashimoto's disease?
- hypothyroidism
| - enlargement d/t elevated TSH trying to stimulate thyroid gland to produce T3/T4
116
What is an iodine deficiency?
- low dietary iodine inhibits sufficient production of T3/T4
| - low T3/T4 negatively feeds back to increase TSH
117
What are most physiological processes dependent on?
- calcium
118
Describe the ratio of calcium in the body
- 98-99% stored in bone via mineralized form
| - 1-2% "free" in ECF
119
T/F: There is more calcium in the ICF than the ECF.
- false, thousands of times less
120
______ exchange of Ca2+ occurs constantly b/t _____, ______, ______, and the _____.
- large
- GI
- bone
- kidney
- cells
121
What are normal serum Ca2+ values?
- 8-10mg/dL
122
What are hypercalcemia serum values?
- > 10.5mg/dL
123
What does PTH do in relation to Ca2+?
- stimulate osteoclasts within minutes to increase serum Ca2+ levels within 1-2hrs
124
Who requires a positive calcium balance?
- growing children
125
What 3 organs maintain calcium exchange?
- GI tract
- kidney
- bone
126
Where is dietary/supplementary Ca2+ absorbed?
- GI tract
127
What are the two forms of supplementary Ca2+?
- calcium carbonate
| - calcium citrate
128
How is Ca2+ best dosed?
- multiple, small doses
129
What is the function of the kidneys in regards to Ca2+?
- reabsorb Ca2+ from glomerular filtrate
| - convert inactive Vit D to calcitriol
130
What is the function of the bones in regards to Ca2+?
- storage
| - increase Ca2+ resorption to increase ECF Ca2+ (osteoclastic activity)
131
What are the primary hormones that regulate ECF Ca2+?
- PTH
- calcitonin
- calcitriol (active form of Vit D)
132
What are the secondary "influencing" hormones that regulate ECF Ca2+?
- GH
- thyroid
- adrenal/gonadal steroids
133
Where is PTH synthesized and released from?
- parathyroid gland
134
What is the function of PTH?
- increase plasma Ca2+ levels
135
What are the target tissues of PTH?
- bone
| - kidney
136
What is the activity of PTH in the bone?
- stimulates osteoclastic activity (resorbs Ca2+ from the bone)
- promotes phosphate release
137
What is the activity of PTH in the kidney?
- converts inactive vit D to active calcitriol
- stimulates Ca2+ resorption in kidney tubules
- stimulates phosphate excretion in kidney
138
What stimulates PTH release?
- small decreases of plasma Ca2+
139
What inhibits PTH release?
- elevated plasma Ca2+
| - elevated calcitriol (neg. feedback)
140
What does prolonged PTH stimulation cause the kidneys to produce?
- more calcitriol
141
What is calcitriol?
- active form of Vit D
142
What is the function of calcitriol?
- increases plasma Ca2+ & phosphate levels
| - other roles in immune and reproduction
143
What is the target tissue of calcitriol?
- intestine
- bone
- kidney
144
What does calcitriol do in the intestine?
- stimulates Ca2+ & phosphate absorption in sm. intestine
145
What does calcitriol do in the bone?
- stimulates osteoclastic activity (resorbs Ca2+ from the bone)
- promotes phosphate release
146
What does calcitriol do in the kidney?
- stimulates Ca2+ resorption in kidney tubules
| - stimulates phosphate resorption in kidney
147
Which hormone stimulates phosphate resorption in kidney? excretion?
- calcitriol
| - PTH
148
Which two hormones work synergistically?
- calcitriol
| - PTH
149
What stimulates calcitriol release?
- elevated PTH
150
What inhibits calcitriol release?
- decreased PTH
151
What is calcitriol's most important role?
- plasma Ca2+ regulation via intestines
152
PTH excretion of phosphate is much ______ than calcitriol resorption of phosphate.
- stronger
153
What is the "other" hormone of the thyroid gland and of Ca2+ homeostasis/balance?
- calcitonin
154
Where is calcitonin produced/secreted from?
- parafollicular cells of the thyroid gland
155
What is the function of calcitonin?
- decrease plasma Ca2+ level
| - promotes reabsorption of Ca2+ back into the bone
156
Calcitonin has a minor role in maintaining plasma Ca2+ levels when compared to what?
- PTH
| - calcitriol
157
What are the target tissues of calcitonin?
- bone
| - kidney
158
What does calcitonin do in the bone?
- inhibits Ca2+ resorption by inhibiting osteoclasts
159
What does calcitonin do in the kidney?
- stimulates Ca2+ and phosphate excretion in renal tubules
160
What stimulates calcitonin release?
- large increases in plasma Ca2+
161
What inhibits calcitonin release?
- decreased levels of plasma Ca2+
