Endocrine Physiology 2 Flashcards
1
Q
Energy Balance equation
A
energy intake - energy out
2
Q
Satiety centre promotes feeling of fullness by suppressing
A
Feedback centre (insulin sensitive)
3
Q
Glucostatic Theory
A
as BG Increases, Drive to Eat Decreases
4
Q
Lipostatic Theory
A
As fat stores increase, drive to eat decreases
5
Q
what type of hormone is leptin
A
peptide released by fat which depresses feeding activity
6
Q
What is a Anabolic Pathway
A
Build up
7
Q
What is catabolic pathway
A
Break down
8
Q
Which part of eating is anabolic?
A
Absorptive after eating
9
Q
Which part of eating is catabolic
A
overnight
between meals
10
Q
What happens when in post absorptive state to brain?
A
Maintain BG Concentration or lead to Hypoglycaemia
11
Q
BG is maintained by synthesising glucose from
A
Glycogen (Glycogenolysis or Amino Acids (gluconeogenesis)
12
Q
Normal rate of BG
A
4.2-6.3
13
Q
What is hypoglycaemia classified as
A
<3nm
14
Q
In diabetes what happens when lose insulin
A
Glucose can’t be taken up so BG rises and glucose detected in Urine
15
Q
The brain only has access to BG when
A
Falls below normal range
16
Q
99% of pancreas operates as
A
Exocrine gland releasing enzymes and NaHCo3
17
Q
Hormones produced by
A
Islets of Langherhan
18
Q
How many types of Islet of Langerhan
A
4
19
Q
A Islet of Langherhan produces
A
Glucagon
20
Q
Beta cells produce what type of insulin
A
Insulin
21
Q
alpha cells produce what type of insulin
A
Alpha cells
22
Q
f cells produce what type of insulin
A
Pancreatic Polypeptide
23
Q
When glucose is taken up by cells from plasma what happens to BG
A
decreases
24
Q
In fed state when insulin dominates what happens to insulin
A
Increased Glucose oxidation
Increased Glycogen Synth
Increased Fat Sync
Increased Protein Synth
25
In fasted stated when glucagon dominates this leads to
Increased Glyconeolysis
Increased Gluconeogenesis
Increased Ketogenesis
26
Insulin is what type of hormone?
Peptide Hormone produced by Pancreatic B cells
27
Insulin does what to glucose?
Stimulates glucose uptake by cells
28
Insulin is synthesised as
Preprohormone preproinsulin which is converted to proinsulin in ER
29
Proinsulin is packaged as what in secretory vesicles during synthesis?
Granules where proinsulin is cleaved again to give insulin and c peptide
30
How is insulin stored?
As C Peptide and Insulin in Granules until B cell activated.
31
What stimulates insulin secretion? (3)
Glucose
Amino acids
Blood Glucose Concentration
32
Which hormone dominates absorptive state
Insulin
33
Which hormone lowers BG
Insulin
34
Excess glucose is stored where?
As glycogen in Liver and Muscle
| As Triglycerols in Liver and Adipose
35
Fatty acids are stored where?
Triglycerides in Adipose Tissue and Fat
36
What is sensitive to ATP within cell for B cells
K+ Ion channel sensitive to ATP within cell (KATP Channel)
37
When glucose is abundant it enters cells through?
GLUT and Metabolism Increases which increases amp within cell = Katp channel closes
38
When glucose enters cell what happens to intracellular k?
It rises depolarising cell.
| Voltage Dependent Ca2+ open and trigger insulin vesicle exocytosis into circulation.
39
What happens when there is high glucose levels in blood?
1. Metabolism Increases
2. ATP Increases
3. KATP Channels Close
4. Cell depolarise and calcium channels open
5. Ca2+ entry act as intracellular signal
6. Ca2+ signal triggers exocytosis and insulin secreted
40
What happens when low glucose?
ATP low so KATP stay open so K+ ions flow out removing positive charge from cell and hyperpolarise it so voltage gated Ca2+ channels remain closed/insulin not cleaved
41
Insulin binds to which receptors?
Tyrosine Kinase Receptors on cell membrane of insulin dependent tissues to increase glucose uptake
42
What is the only hormone that lowers BG
Insulin
43
What does insulin do in Muscle and Adipose Tissue
Stimulates mobilisation of specific glucose transporters: GLUT 4 which reside in cytoplasm of these cells
44
Where does GLUT 4 reside in muscle and adipose tissue?
Cytoplasm
45
When stimulated by insulin what happens to GLUT4
Migrates to membrane and able to transport glucose into cell.
46
When insulin stimulation stops what do GLUT 4 transporters do?
Return to cytoplasmic pool
47
What process allows glucose to enter cells
Exocytosis
48
What are the only types of tissue that are insulin dependent to take up glucose
muscle and fat
49
In other tissues glucose uptake is via other GLUT transporters which are not?
Insulin dependent
50
What allows glucose uptake in many tissues
Brain
Kidney
Red Cells
51
What allows glucose uptake in pancreas and liver
GLUT 2
| B cells
52
Is the liver insulin dependent
No
53
How does liver take up glucose
GLUT 2 Transporters
54
GLUT 2 Transporters are said to be?
Insulin Independent
55
Glucose enters liver how?
Down concentration gradient
56
Does insulin have any direct effect on liver?
No
57
Glucose transport into where in liver is affected by insulin status
Hepatocytes
58
In fed state liver takes up glucose because
Liver activates Hexokinase which lowers glucose moving glucose into cells
59
In fasted state liver synthesises glucose via
glycogenolysis and gluconeogenesis increasing glucose movement out of cells into blood
60
What does insulin do in muscle and liver
increases glycogen synthesis and inhibits glycogen phosphorylase
61
what does insulin do in muscle
increase amino acid uptake into muscle
62
what does insulin do to protein
increase protein synthesis
| inhibit proteolysis
63
What does insulin do in liver
inhibits enzymes of gluconeogenesis
64
Insulin has what type of effect on growth hormone
Permissive
65
what does insulin do to K+
promotes k+ ion entry into cells by stimulations Na/K+ ATPASE
66
Insulin binds to what type of receptor
tyrosine kinase receptor
67
Insulin half life
5 Mins
68
Once insulin action is complete what happens to insulin bound receptors
internalised by endocytosis
69
What 5 factors increase insulin release
```
Increased BG
Increased Amino Acids
Glucagon
Gastrin/Secretin/CCK/GLP-1, GIP
Vagal Nerve Activity
```
70
what 4 factors inhibit insulin release
Low BG
Somatostatin (GHIH)
Sympathetic a2 effects
Stress eg Hypoxia
71
Glucagon is what type of hormone produced by?
Peptide Hormone
| Produced by a cells of pancreatic islet cells
72
What is the primary purpose of Glucagon
Raise Blood Glucose acting mainly on liver
73
Glucagon half life
5-10 mins
74
Glucagon is most active
in post absorptive state
75
Glucagon receptors are what type of receptor
G protein coupled receptors linked to adenylate cyclase/cAMP system which when activated phosphorylate specific liver enzymes
76
What are the 3 actions of glucagon and what is net result
Increased glycogenolysis
Increased glcuoneogenesis
Formation of Ketones from fatty acids (Lipolysis)
Net result = Elevated BG
77
What is the formation of ketones from fatty acids called
Lipolysis
78
Where do the actions of glucagon take place
Liver
79
Free fatty acids become ketone bodies through
B Oxidation
80
Brain can only use what for energy
Glucose and Ketones
81
What do amino acids do in hypoglycaemia
stimulate insulin release which in the absence of glucagon stimulate glucose uptake into cells lowering BG.
82
Increased glucose does what to insulin and glucagon
Increased insulin
| Decreased Glucagon
83
Decreased glucose does what to insulin and glucagon
Increased Glucagon
| Decreased Insulin
84
Amino acids in plasma stimulate
release of insulin and glucagon
85
What 5 stimuli promote glucagon release
```
Low BG <5mm
High Amino Acids
Symp Innervation and Epinephrine B2 effect
Cortisol
Stress
```
86
What 4 stimuli inhibit glucagon release
1. Glucose
2. Free Fatty Acids and Ketones
3. Insulin
4. Somatostatin
87
Increased Parasymp Activity does what to Insulin and Glucagon
Increases both
88
Somatostatin is what type of hormone
Peptide hormone
89
Somatostatin is secreted by?
D Cells of Pancreas
90
Somatostatin action
Inhibit activity in GI Tract
91
Entry of glucose into skeletal muscle is increased during exercise when
even in absence of insulin.
Insulin independent increase in GLUT 4 Transporters
92
Exercise does what to insulin sensitivity of muscle
Increase
93
In non active muscle insulin binds to
receptor which then leads to glucose transporters GLUT4 migrating to cell membrane allowing glucose to enter
94
Exercise causes glucose uptake what?
independently of insulin and increases sensitivity of muscle to insulin
95
When adipose tissue is broken down what is released
Adipose Tissue
96
In starvation liver will convert excess free fatty acids into
Ketone bodies
97
Ketone body uptake is
insulin dependent
98
In poor controlled insulin dependent diabetes what depresses ketone body uptake
lack of insulin
99
In Type 2 Diabetes what becomes insensitive to insulin
Peripheral Tissues
100
What happens to B cells in Type 2 Diabetes
Remain intact and appear normal
101
What percentage of diabetic patients are insulin resistant
90%
102
Type 1 Diabetes what leads to increase BG
inadequate insulin release
103
Type 2 Diabetes what leads to increase BG
inadequate tissue response
104
What is the diagnostic criterion for diabetes
Hyperglycaemia detected by Glucose Tolerance Test
