MET2 OVERVIEW Flashcards
1
Q
Precursors to insulin - insulin production
A
Preproinsulin (110 amino acids) to proinsulin (86 amino acids) to insulin (51 amino acids)
2
Q
Function of glucokinase enzyme
A
Senses the level of glucose in the beta cell of the pancreatic island - conversion of the glucose to glucose-6-phosphate for release of insulin
3
Q
Location of GLUT1
A
Beta cell of pancreatic island
4
Q
Location of GLUT4
A
Muscle cells and adipocytes
5
Q
Function of insulin at the muscle and the adipocytes
A
Increased glycogesis
Reduced glucogenolysis
Increased lipogenesis
Reduced glygenolysis
6
Q
Function of insulin at the liver
A
Increased mRNA translation for increased protein production
Reduced breakdown of proteins
7
Q
Enzyme causing lipolysis
A
Lipase
8
Q
Ketone bodies are produced from
A
Acetyl CoA
9
Q
Equation to denote acid being added to water
A
HA –> H+ + A- (conjugate base)
10
Q
Normal pH for human blood
A
7.35-7.45
11
Q
pH of human blood leading to death
A
<6.8
>8
12
Q
Three systems to maintain the blood pH and how long does each one take
A
Chemical system - immediate action
Respiratory system - 1 to 3 minutes
Renal system - hours to days
13
Q
Three chemical buffer systems
A
Phosphate
Bicarbonate
Proteins e.g. Hb and albumin
14
Q
Definition of anion gap
A
The difference between the measure anions and the measured cations
15
Q
Cation
A
Ion with a positive charge
16
Q
Anion
A
Ion with a negative charge
17
Q
What is excluded when calculating the anion gap and why?
A
Generally exclude potassium K+ because this value is generally negligible
18
Q
Normal range for anion gap
A
8-16
19
Q
Significance of increased anion gap
A
Increased anion gap - metabolic acidosis
20
Q
Significance of decreased anion gap
A
Decreased anion gap - metabolic alkalosis
21
Q
General cations measured for the anion gap
A
Na+
Sometimes K+
22
Q
General anions measured for the anion gap
A
HCO3-
Cl-
23
Q
Why are veins more acidic than arteries?
A
Veins contain more CO2 - acidic
24
Q
Enzyme involved in the reabsorption of HCO3- in the proximal convoluted tubule
A
Carbonic anhydrase
25
Three common causes for metabolic acidosis
Diarrhoea
Ketoacidosis
Lactic acidosis
26
Three common causes for metabolic alkalosis
Vomiting
Hypokalaemia
Ingestion of HCO3-
27
What is the blood supply to the liver?
25% - coeliac trunk
| 75% - hepatic portal system of veins
28
What is portal hypertension - how does this occur?
Due to cirrhosis of the liver - fibrosis of the parenchyma - blood cannot perfuse to the whole of the liver - builds up and there is a state of hypertension
29
How can you calculate the portal pressure gradient?
Difference between the normal portal pressure and the pressure of the IVC - if this is greater than 10: portal hypertension
Normal portal pressure - 9
IVC pressure - 2-6
30
What is the consequence of cirrhosis on a patient and why?
Splenomegaly - increased portal hypertension - increased blood flow to the spleen - causes it to swell
31
Causes of cirrhosis
Alcoholism
| Hepatitis B/C
32
Why does cirrhosis result in ascites?
Damage to the liver - cannot produce enough albumin - reduced plasma proteins in the blood - blood has an increased water potential - increased movement of water out of the blood into the extra cellular tissues of the peritoneum - swelling in the abdomen - ascites
33
Anastomoses of which veins result in oesophageal varices?
LEFT gastric vein and oesophageal vein
34
Cause of caput medusae
Blood attempts to leave the portal system due to the increased pressure - formation of this from mass blood movement
35
Blood supply to the gallbladder
Cystic artery
36
What is contained within the ducts of the biliary tree?
Bile
37
Will a gallstone in the cystic duct cause jaundice?
No
38
Will a gallstone in the common bile duct cause jaundice?
Yes
39
Will a gallstone in the hepatopancreatic ampulla cause jaundice?
Yes
40
What is an adipokine?
Cytokine released by adipose tissue
41
Does insulin resistance mean that diabetes will occur? Why?
No - because there is islet compensation to allow for the generation of new beta cells which can also be larger and secrete even more insulin
42
Metformin - how does this drug act and what is it used for?
Drug used for the treatment of diabetes
Increases sensitivity to insulin at the muscle cells and at the adipocytes
Also acts to decrease the levels of gluconeogenesis
43
Other forms of diabetes, not T1DM or T2DM
Gestational
MODY - mature onset diabetes of the young
LADA - late autoimmune diabetes of adults
44
What is the most common sign of diabetic nephropathy? in a test?
Proteinuria i.e. presence of protein in the urine due to insufficient filtration by the glomerulus
45
What is the significance of raised protein kinase C levels?
Increased permeability of blood vessels
Increased occlusion of blood vessels and vasoconstriction
Increased mitochondrial dysfunction
46
What is the hypothalamo-hypophyseal portal system?
System of blood vessels connecting the hypothalamus to the anterior pituitary
47
What are the vascular connections of the hypothalamus and the pituitary gland?
Superior hypophyseal artery from hypothalamus to the APG
Secondary capillary plexus between anterior and posterior PGs
Drainage into the hypophyseal portal vein from the APG
48
Which nerve runs anteriorly to the thyroid gland?
Recurrent laryngeal nerve
49
What is the blood supply to the pancreas?
Coeliac trunk - splenic artery - transverse pancreatic branch
SMA - inferior pancreato-duodenal artery
50
Blood supply to the adrenal glands
Superior adrenal artery from the inferior phrenic
Middle adrenal artery from the abdominal aorta
Inferior adrenal artery from the renal artery
51
Functions of the kidney
Excrete waste products of metabolism
Maintain water and electrolyte balance
Maintain acid/base balance
52
Which kidney is more superiorly located and why?
The left kidney is located more superiorly
| The right kidney has the liver directly superior to it and this pushes down
53
What is situated on top of each kidney?
Adrenal glands
54
What is the hepatorenal recess and where is this?
Subhepatic recess/Morrison's pouch
Separates the live from the right kidney
This is where fluid collects if a patient is lying supine
55
When might fluid collect in the hepatorenal recess?
Ascites
| Pancreatitis
56
Which organ lies anterior to both and stretches across from the right to the left kidney?
Pancreas - head of the pancreas at the right kidney and tail of the pancreas at the left kidney
57
Is the pancreas retro or intraperitoneal?
Pancreas is intraperitoneal apart from the tail which is retroperitoneal
58
What is the shape of the right adrenal gland?
Pyramidal/triangular
59
What is the shape of the left adrenal gland?
Crescent shaped
60
Are the kidneys retroperitoneal or intraperitoneal?
Kidneys are retroperitoneal
61
What is Gerota's fascia?
This is the renal fascia - the kidneys are encapsulated in their own layer of fat
62
Arcuate line
Aka. the douglas line
Horizontal line along the rectus abdominis where the inferior epigastric vessels perforate the abdominal rectus sheath
Superiorly to the arcuate line, they are outside of the sheath and inferiorly, they are inside the sheath
63
'Arcuate nucleus'
Main control centre of hunger located in the hypothalamus
64
How does hypothalamus control satiety and hunger?
Via usage of neurotransmitters
65
Orexigenic vs. anorexigenic
Orexigenic - appetite stimulating
| Anorexigenic - appetite suppressing
66
Orexigenic neurotransmitters
Neuropeptide Y (NPY)
Agouti related peptide (AgRP)
MHC
67
Anorexigenic neurotransmitters
POMC
| CART
68
Effect of serotonin on the neurotransmitters and on appetite
Reduce NPY and increase POMC
| Appetite suppressant
69
Effect of ghrelin on the neurotransmitters and on appetite
Decrease NPY
| Appetite stimulant
70
Which cells and what organ release GLP-1?
L-cells of the small intestine
71
What organ releases ghrelin and which cells?
Stomach
| Parietal cells
72
What is ghrelin otherwise known as?
'Hunger hormone'
73
Effect of GLP-1 on the neurotransmitters and on appetite?
Decrease NPY and increase POMC
| Appetite suppressant
74
To what receptor does GLP-1 bind to?
Y2R
75
What other hormone does GLP-1 have the same effect as?
Serotonin
76
Where is the hormone cholecystokinin secreted from - what organs and which cells?
Duodenum and large intestine
| Enterendocrine cells
77
Effect of cholecystokinin on appetite?
Suppress appetite
78
Effect of PYY on neurotransmitters and on appetite
Suppress appetite
| Reduces NPY and increase POMC
79
When is PYY released?
When there is something in the gut
80
Effect of leptin on neurotransmitters and appetite
Reduces the level of AGRP
| Appetite suppressant
81
Where are leptin receptors located and which are the most important?
Throughout range of tissues
| Most important are in the hypothalamus
82
Cells that secrete leptin
Adipocytes
| NB. white adipose tissue
83
Who secretes more leptin and why?
Those with a greater level of body fat - have more adipocytes
84
What is leptin resistance?
The idea that people can learn to ignore the feeling of satiety given by leptin release and continue to eat anyway
Results in increased levels of obesity
85
Effect of insulin on neurotransmitters and on appetite
Decrease the levels of AGRP
| Appetite suppressant
86
Effect of malonyl co-A on neurotransmitters and on appetite
Increase POMC
| Appetite suppressant
87
What controls malonyl coA levels?
AMPK - AMP kinase
| Calcium levels - controlled by ghrelin so controlled by gut hormones
88
Effect of gut microbes on appetite
Believed to have a role - being researched
| Different gut microbes in lean and overweight people
89
Drug which acts to increase appetite
Cannabinoids
90
How do you calculate BMI?
Weight (kg) / height (m) squared
91
'Syndromic monogenic obesity'
Single gene mutation causing obesity associated with a range of other features e.g. mental retardation and dysmorphic features
30 potential gene mutations
92
'Non-syndromic monogenic obesity'
Single gene mutation causing obesity and no other features
| 12 potenital gene mutations
93
Apple shape vs. pear shape - which is most dangerous and why?
Apple shape - more visceral fat - increased risk of health related issues
94
Blood supply to anterior pituitary gland
Supra hypophyseal artery
95
Blood supply to posterior pituitary gland
Inferior hypophyseal artery
96
Vascular connection of anterior and posterior pituitary glands
Secondary capillary plexus
97
Venous drainage from the anterior pituitary gland
Hypophyseal portal vein
98
What structure does the pituitary gland sit in and why is this important to be aware of with a pituitary tumour?
Sella turcica - has bone anteriorly and posteriorly but no bone laterally
Tumour will grow out laterally
99
What are the first structures that a pituitary adenoma will cause damage to?
CNs III, IV and V1, V2, V3
Optic chiasm
Carotid artery
100
What visual field defect will pituitary adenoma commonly result in?
Bitemporal hemianopia
101
What is meant by primary underactivity of a hormone?
a
102
What is meant by secondary underactivity of a hormone?
a
103
What affects the thyroid hormone levels in the thyroid axis?
a
104
What affects the GH hormone levels in the GH axis?
a
105
When in life would you have greater secretion of GH?
a
106
What is the condition where there are elevated levels of cortisol?
a
107
What is the conidtion where there is too little levels of cortisol?
a
108
Independent of cortisol hormone production, how might one develop Cushing's syndrome?
a
109
Function of oxytocin
a
110
Function of ADH
a
111
Hormone released from thyroid gland - name
a
112
Active form of thyroid gland
a
113
Enzyme responsible for conversion of T4 to T3
a
114
Site of conversion of T4 to T3
a
115
Isoforms of enzyme that convert T4 to T3
a
116
Isoform of enzyme that inactivates T4 (and T3)
a
117
Isoform of deiodinase enzyme expressed in the periphery
a
118
Isoform of deiodinase enzyme expressed in the brain and pituitary gland
a
119
What happens to the levels of T4 and D2 during hypothyroidism?
IMPORTANT FOR EXAM
During hypothyroidism, T4 levels go down
| D2 gets upregulated SO more T4 is converted into T3
120
What happens to the levels of T4 and D2 during hyperthyroidism?
IMPORTANT FOR EXAMS
In hyperthyroidism, there are very high levels of T4
| D2 gets down regulated so the brain converts less T4 to T3
121
'Thyroid binding globulin' and when does this increase?
a
122
Three layers of the adrenal cortex of the adrenal gland and what they release
Glomerulosa - Mineralocorticoids e.g. aldosterone
Fasciculata - Glucocorticoids e.g. cortisol
Reticulosa - Androgens e.g. testosterone
123
Three types of hormones
Peptide
Steroid
Amine
124
Conn's syndrome and effect
Hyperaldosterone
125
Effect of glucocorticoids on the immune system
Inhibition of the immune system
126
'Cushing's syndrome'
Elevated levels of cortisol
127
'Addison's disease'
Primary adrenal cortex failure
128
'Adrenal hyperplasia'
| Comes up in exams
Adrenal hyperplasia - causes various enzymes to not work congenitally SO lack of production of hormones from adrenal cortex
129
Example of enzyme deficiency in adrenal hyperplasia
21-hydroxylase
130
Two signs of adrenal hyperplasia
Adrenal insufficiency
| Virrilisation - female babies born with male genitalia
131
Hormones released from adrenal medulla
Catecholamines e.g. adrenaline and noradrenaline
132
Cells that release catecholamines
Chromaffin cells
133
Effect of alpha 1 adrenoreceptor activation
Bronchial smooth muscle contraction i.e. vasoconstriction
134
Effect of beta 1 adrenoreceptor activation
Positive ionotrophic and chronotrophic effect on the heart
| Increased renin
135
Effect of beta 2 adrenoreceptor activation
Bronchial, vascular, uterine smooth muscle relaxation
| Glycogenolysis
136
Effect of Cohn's syndrome
Increased aldosterone
Reduced plasma renin
Hypertension
