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Flashcards in diabetes Deck (49):
1

difference betweenDKA and HHS?

DKA - absolute insulin deficiency
- generally lower blood glucose levels
- lipolysis and ketogenesis
- 3-6 L water deficiet
- plasma Na usually normal
- younger patients

HHS- relative insulin deficiency
- blood glucose levels often higher
- often absent lipolysis and ketogenesis
- 8-10L water deficiet
- plasma sodium high
-older patients

2

what does the thyroid gland develop as?

an endodermal downgrowth ( thyroglossal duct). the foramen caecum at the back of the tongue marks the site of the down growth.

3

what shape is the epithelium in inactive follicles ?

simple ,low cuboidal or squamous

4

What hormone regulates the activity of the thyroid gland and where is it produced?

THYROID STIMULATING HORMONE FROM ADENOHYPOPHYSIS

5

Which cell organelle produces the protein part of thyroglobulin?

rough endoplasmic reticulum

6

where is the sugar component added to thyroglobulin ?

the golgi apparatus

7

Which enzyme, synthesized by the follicle cell, enables iodide to be converted to iodine?

thyroid peroxidase

8

The enzyme phosphofructokinase (PFK1) is a key regulator of glycolysis. Which of the molecule directly inhibits PFK1 activity?

ATP

9

What does glucagon do?

It reduces glycolysis by inhibiting phosphofructokinase

10

Which enzyme is activated by insulin in skeletal muscle after a meal?

glycogen synthase

11

what is the role of calcium ?

structural - teeth bone
neuromuscular - muscle contraction , neurotransmitter release
enzymatic - coagulation factor coenzyme
signalling - intracellular messenger

12

how much calcium is excreted in urine and faecesin 24 hrs

2.5mmol/24HRS
20mmol /24 hrs in faeces

13

what 3 different forms is calcium present in serum?

bound to albumin 46%
free ions 47%
complexed with citrate and phosphate

14

what is the normal range for total serum calcium?

2.2-2,6mmol/l

15

what alters the concentration of Ca2+

changes in H+ and pH

16

what happens to calcium during alkalosis ?

H+ dissociates from albumin and calcium binding to albumin increases which results in a decrease of free calcium conc. this can produce signs of hypocalcaemia even though the total serum calcium concs are not altered . in acute acidosis the reverse is true.

17

what is plasma calcium controlled by?

the action of two hormones; parathyroid hormone and 1,25 dihydroxycholecalciferol (calcitriol)

18

what is PTH?

a polypeptide secreted from the parathyroid glands in response to a decrease in the plasma concentration of free Ca2+ and this change is sensed by a specific Ca2+ sensing protein in the cell membrane of the parathyroidglands

19

How does PTH act to increase the plasma Ca2+ concentration?

-stimulation of bone resorption , resulting in the release of calcium phosphate
- enhancement of intestinal Ca2+ and phosphate absorption by promoting the formation within the kidney of calcitrol , the major active metabolite of vit D
- increased active renal Ca 2+ reabsorption

20

do the cells stain differently in the zona glomerulosa and fasiculata

YES- THE CELLS STAIN MORE
DARKLY WITH SMALL DARK GRANULES IN THEIR CYTOPLASM

21

What is the three-dimensional
organisation of the cells within the zona fasciculata?

RADIAL COLUMNS OF CELLS THROUGH MOST OF THE DEPTH OF THE CORTEX

22

The cells forming the zona fasciculate appear pale in an H&E stained section and contain
empty looking, small rounded profiles. A name for these is...?
and What has been eluted out of these cells during routine processing for histology?

spongiocytes.
lipids and cholesterol

23

what is the approx diameter of fenestrated capillaries ?

7um

24

What does the term reticularis tell you about the
3D organisation of secretory cells in this part of the suprarenal cortex?

the secretory cells from a 3d network

25

where does the supra renal medulla recieve blood from first?

the capillaries and sinusoids of the suprarenal cortex ,
second from arterioles passing from the capsule to the medulla

26

what is the mechanism of orlistat?

inhibition of pancreatic lipase

27

Where are the insulin receptors?

Tyrosine kinase receptors are found in the liver and striated muscle and adipocytes primarily

28

Describe glucagon signalling

Glucagon binds to the glucagon receptor
- G- protein coupled receptor
- found in hepatocytes
- increases cyclic AMP
- cAMP stimulates cAMP - dependent protein kinase ( PKA)

29

Types of insulin deficient diabetes

Type 1
MODY
pancreatitis
Cystic fibrosis
Haemochromotosis

30

Insulin resistant diabetes

Type 2
Gestational
Steroid induced
Acromegaly

31

Metabolic acidosis character

H+ high

pH is low

HCO3- Is low

CO2 is low

32

What does leptin do?

Tells hypothalamus about amount of stored fat

33

What does adiponectin do

Reduced levels of free fatty acids

34

What does resistin do

Enhances hypothalamic stimulation of glucose production

35

In normal renal glucose handling 90% of glucose is reabsorbed by

SGLT2 in the PCT
the rest by SGLT1

36

Hyponatraemia

<135mmol/l
Commonest disorder of electrolyte balance

37

What is type 2 diabetes caused by?

Inadequate insulin secretion and peripheral insulin resistance .

38

What happens in early stages of T2

The response to insulin resistance is to produce more insulin and an increase in insulin secretionby pancreatic beta cells causing hyperinsulinaemia . Beta cells are eventually unable to compensate adequately and blood glucose sugar rises -> hyperglycaemia

39

What happens when there is too much glucose in the blood

It gets converted to sorbitol via polyol pathway . Sorbitol cannot cross the cell membranes and therefore accumulates inside cells and produces osmotic stresses -> drawing h2o into insulin dependent tissues - there is a build up of ROS and build up of oxidative stress

40

What medications are insulin sensitisers ?

Biguanides - metformin

Thiazolidindiones - ploglitazone

41

What medications increase insulin secretion

Sulphonylureas - glibenclamide

Incretin based therapies -
* EXENATIDE mimics GLP1
* SITAGLIPTIN inhibits DPP4

42

What causes diabetic retinopathy?

Hyperglycaemia causes increased retinal blood flow and disrupts intracellular metabolism in retinal endothelial cells , leading to impaired vascular autoregulation -> increased production of vasoactive substances and endothelial cell proliferation .
Results in capillary hyperperfusion and closure causes chronic retinal ischaemia stimulating growth factors like VEGF that increase vascular permeability - causing retinal leakage and exudation

43

What is modular diabetic glomerulosclerosis

Thickening of basement membrane and expansion of mesengial cells

44

Causes of diabetic foot

Due to combo of ischaemia , ulceration and infection

45

Peripheral neuropathy includes

Charcot foot -change shape of feet

Neuropathic ulcer

Clawing of toes

Glove and stocking neuropathy

46

Peripheral vascular disease

Loss of leg hair

Absent pulses cold feet
Proximal artery occlusion

Distal gangrene

47

What is vasa nervorum

are small arteries that provide blood supply to peripheral nerves. These vessels supply blood to interior parts of nerves and their coverings.

48

Reason for diabetic neuropathy?

Occurs secondary to metabolic disturbance , prevalence is related to duration of diabetes and degree of metabolic control.

Examination reveals capillary damage and occulsion of vasa nevorum whcih decreases blood suppply to nerves whcih causes axonal degradation and thickening of Schwann cell basal lamina

Causes impairments in nerve signalling sensory and motor

49

Signs of diabetic neuropathy

Finished vibratory perception
Decreased lower limb reflexes
Reduced protective mechanism pressure / temp/ pain
Decreased proprioception