Disorders of carbohydrate metabolism Flashcards
Carbohydrates (CHO)
Source of energy for the body
Essential energy for some tissues like _____ and ______
brain and RBC
Carbohydrates (CHO)
Exist as
Polysaccharides – ____,_______
Disaccharides – _____,______
Monosaccharides – _______,________
Starch, Glycogen
Lactose, sucrose
Glucose, Fructose
Carbohydrates (CHO)
Complex CHO taken as food are digested to _______ which are then absorbed in the intestines
monosaccharides
_______ is the most used monosaccharide as metabolic fuel
Glucose
Many tissues are capable of ______ glucose completely to ______
Oxidizing
carbon dioxide
Others metabolize glucose only as far as _______, which can be converted back into glucose, principally in the _____ and also in the _______, by _________
lactate
liver
gluconeogenesis
Tissues capable of completely oxidizing glucose, ______ is produced if insufficient oxygen is available (_________ metabolism)
lactate
anaerobic
The body’s sources of glucose are _______ and endogenous production by _________ (release of glucose stored as _____) and ________ (glucose _______ from, for example, _______,______ and most _________).
dietary carbohydrate
glycogenolysis; glycogen
gluconeogenesis; synthesis
lactate, glycerol and most amino acids
Glycogen is stored in the ______ and ________ , but only the former contributes to blood glucose.
liver and skeletal muscle
Regulation of blood glucose
Blood glucose concentration depends on the _____________________
influx of glucose into circulation and use
Regulation of blood glucose
Homeostatic mechanisms maintains blood glucose around ____-____mg/dL.
50 -110 mg/dL.
Regulation of blood glucose
The _______ produces hormones that regulate blood glucose concentration
pancreas
Pancreatic hormones that affects glucose
List 3
Glucagon
Insulin
Somatostatin
Pancreatic hormones
Glucagon – from _____ cells; ____eases blood glucose concentration
Insulin – from _______ cells; ____eases blood glucose concentration
Somatostatin - synthesized by ____ cells); it _______________________ , resulting in ____ease in plasma glucose level
alpha; incr
beta; Decr
delta; Inhibits both insulin, glucagon and growth hormone release
incr
Pancreatic hormones
Other hormones – (Aid or Counter?) insulin action: _____,______hormones, _______,________ hormone, _____
Counter Epinephrine
thyroid
Cortisol
Growth; ACTH
Pancreatic hormones
Two most important hormones in glucose homoeostasis are ______ and _____
insulin and glucagon.
Insulin is a ____ amino acid polypeptide, secreted by the ____-cells of the pancreatic islets of Langerhans in response to a (rise or fall?) in blood glucose concentration.
51; β ; rise
Insulin
It is synthesized as a _______,________.
This molecule undergoes ______ prior to secretion to form insulin and _______
prohormone, proinsulin
cleavage
C-peptide.
Insulin secretion is also stimulated by gut hormones collectively known as _____, particularly _________ and _______________(_____ formerly known as ___________ ).
incretins
glucagon-like peptide-1 (GLP-1)
glucose- dependent insulinotropic peptide (GIP
gastric inhibitory polypeptide
Incretin release is stimulated by ______, so that _______ begins to increase before blood ________
food
insulin secretion
glucose concentration.
Biosynthesis of insulin
The cleavage of ________ produces insulin, consisting of two polypeptide chains linked by ________, and _________
proinsulin
disulphide bridges
C-peptide.
Biosynthesis of insulin
Insulin promotes the ______ of glucose from the ______ through stimulating the relocation of the insulin-sensitive _______ glucose transporter from the _____ to __________, particularly in ______ and ________.
removal; blood
GLUT-4 ; cytoplasm ; cell membranes
adipose tissue ; skeletal muscle.
Biosynthesis of insulin
Insulin also stimulates glucose uptake in the liver, but by a different mechanism: it induces the enzyme ______, which ___________ to form ________, a substrate for _______ synthesis.
This process maintains a (low or high?) intracellular glucose concentration and thus a ___________ that facilitates glucose uptake.
glucokinase ; phosphorylates glucose
glucose 6- phosphate
glycogen ; low
concentration gradient
Insulin stimulates glycogen _______ (and inhibits glycoge______)
synthesis
nolysis
Binding of insulin to its receptor leads to activation of the _______ pathway and phosphorylation of various _______.
These include _________, which dephosphorylates both ________ (thereby activating it and promoting ________ ) and _________ (rendering it inactive and thus preventing the activation of ________ , the key enzyme of _________).
postreceptor pathway
effector proteins
phosphoprotein phosphatase ; glycogen synthase
glycogen synthesis; phosphorylase kinase ; glycogen phosphorylase
As a result of insulin’s actions in the liver , in the fasting state, when insulin secretion is ________, hepatic ________ is stimulated and glucose is ________ into the blood.
inhibited
hepatic glycogenolysis is stimulated
liberated
Insulin also exerts control over glycolysis and gluconeogenesis, stimulating the former and reciprocally inhibiting the latter, by stimulating the expression of ______________, ______________ and the enzyme responsible for the synthesis of the key allosteric modifier, ______________
phosphofructokinase
pyruvate kinase
fructose 2,6-bisphosphate
Disorders of CHO metabolism
1. HYPOGLYCAEMIA
Blood glucose less than ____ mg/dl (____ mmol/L)
50 mg/dl (2.8 mmol/L)
Disorders of CHO metabolism
1. HYPOGLYCAEMIA
Causes include __________, __________ insulin release (eg, due to _________, _______ or ————- , excess __________ without food intake inhibiting __________
starvation
excess ; insulinoma
excess insulin or hypoglycaemic drug administration
alcohol ; gluconeogenesis
Disorders of CHO metabolism
1. HYPOGLYCAEMIA
Features – increase release of anti insulin hormones causing _____,___________,__________ , impaired _________, confusion, seizures, coma
anxiety
dizziness
perspiration
nerve function
Disorders of CHO metabolism
1. HYPOGLYCAEMIA
Diagnosis
There are ____ stages in the diagnosis of hypoglycaemia: ___________ and ________
Two
confirmation of the low blood glucose concentration and elucidation of the cause
Disorders of CHO metabolism
1. HYPOGLYCAEMIA
Diagnosis
Symptoms will usually be present only with a concentration of less than ____ mmol/L.
Neonates, however, often develop features only when the blood glucose is <____ mmol/L.
2.2 mmol/L.
<1.5 mmol/L.
Disorders of CHO metabolism
1. HYPOGLYCAEMIA
Diagnosis
Glucose meters :
can be used to note clinical suspicion of hypoglycaemia
they are sufficiently accurate at low blood glucose concentrations to provide a definitive diagnosis
formal laboratory measurements should not be used
Blood must be collected into a container with ______, to inhibit ______.
T/F
T
F. they are insufficiently accurate at low blood glucose concentrations to provide a definitive diagnosis
F . formal laboratory measurements should be used.
fluoride; glycolysis.
Disorders of CHO metabolism
1. HYPOGLYCAEMIA
MANAGEMENT
Give glucose either by _______ or ______
The presence of a low blood glucose concentration, symptoms of hypoglycaemia and their abolition by giving glucose constitute ‘______________’.
mouth or parenterally
‘Whipple’s triad’.
Disorders of CHO metabolism
1. HYPOGLYCAEMIA
MGT
The cause of the hypoglycaemia may be obvious from the patient’s history, particularly in _______ hypoglycaemia. With _____ hypoglycaemia, many possible causes can be eliminated by simple tests.
reactive
fasting
Disorders of CHO metabolism
2. LACTOSE INTOLERANCE
Inability to _____________________ which is present in human and cow milk
digest to digest milk sugar (Lactose)
Disorders of CHO metabolism
2. LACTOSE INTOLERANCE
________ or ________ ———— in the small intestine
Deficiency or abnormal lactase enzyme
Disorders of CHO metabolism
2. LACTOSE INTOLERANCE
Symptoms – mild to severe – ————-,———-,_______,_______,_______
Usually starts _______ to _______ after food ingestion
abdominal pain, bloating, gas, diarhoea, nausea.
30 mins to 2 hrs
Diagnosis of Lactose intolerance
________ test
_______[[ test
Hydrogen breath
Stool acidity
Diagnosis of Lactose intolerance
Hydrogen breath test – Patient drinks ___________ drink and the ______ is analysed at intervals to check ________.
___________ will cause ________ in breath
lactose laden drink
breath ; Hydrogen level.
Undigested lactose
elevated hydrogen in breath
Diagnosis of lactose intolerance
Stool acidity test – Good for ______;
Undigested lactose causes ___________ in stool due to _________
infants
increased acidity (lactate)
bacterial action
Diabetes mellitus
Diabetes mellitus is a condition characterized by ____________ with a tendency to _____glycaemia and is due to a relative or absolute _________
abnormal glucose tolerance
hyper
deficiency of insulin.
Diabetes mellitus
It can occur secondarily to other __________ but the majority of cases are __________.
pancreatic disease
idiopathic
Diabetes mellitus
Type 1 typically affects (younger or older?) patients.
It is an _______ disease and usually has an (acute or chronic?) onset.
Type 2 typically affects _____-aged and _____ people (although it is increasingly being diagnosed in ——- _____ people) and has a more _______ onset. Genetic and environmental factors are important in its pathogenesis.
Younger ; autoimmune; acute
middle; elderly; obese young; gradual
Diabetes mellitus
The prevalence of both types of diabetes, but particularly of type ___, is increasing.
Hyperglycaemia leads to _____ and causes an _______, producing the classic clinical features of _______ and ________
type 2
glycosuria ; osmotic diuresis
polyuria and polydypsia.
Diabetes mellitus
Patients with type 1 DM may develop diabetic ______ in which hyperglycaemia, together with increased _____,_______,_________ , leads to severe dehydration.
diabetic ketoacidosis
lipolysis, proteolysis and ketogenesis
DIABETES MELLITUS
Pre-renal uraemia and a profound metabolic respiratory acidosis.
Patients with type 2 DM appear to have (sufficient or insufficient?) insulin secretion to prevent the excessive _______ and ________ that are essential to the production of ________.
Instead, inadequate treatment may lead to the development of very severe ______ and _________, producing a (ketotic or non-ketotic?) , _______ state.
sufficient
lipolysis and ketogenesis
ketoacidosis.
hyperglycaemia and dehydration
non-ketotic, hyperosmolar state.
DIABETES MELLITUS
Pre-renal uraemia and a profound metabolic respiratory acidosis.
In type 2DM
Both ketoacidosis and non-ketotic hyperosmolar coma are medical emergencies; their management involves _________ and _________ , with general supportive measures and treatment of any specific pre-existing or complicating factors
provision of fluid and insulin
DIAGNOSIS DIABETES MELLITUS
Normal : Fasting= < _____ mmol/L
Impaired fasting:
fasting venous plasma=____-____ mmol/L
2 hr PP= <_____ mmol/L
6.1
6.1 – 7.0
7.8
DIAGNOSIS DIABETES MELLITUS
Impaired glucose tolerance
fasting venous plasma= <____ mmol/L
2hr PP =_____ -_____ mmol/L
7.0
7.8 – 11.1
DIAGNOSIS DIABETES MELLITUS
DM
fasting venous plasma = or > _____ mmol/L
2hr PP = or > ____ mmol/L
7.0
11.1
2 hr post standard glucose load can stand for OGTT
T/F
T
Complications of DM
Microvascular complications - ____pathy, _____pathy and ____pathy and _________.
Retino
Neuro
Nephro
atherosclerosis
Complications of DM
The presence of microalbuminuria may indicate _________ and ___________ ————.
Diabetes is associated with ______ that predispose to ________
early (and potentially treatable) nephropathy
dyslipidaemia; atherosclerosis
Complications of DM
The treatment of diabetes is aimed at relieving symptoms and preventing both short- and long-term complications.
T/F
atherosclerosis
Complications of DM
The efficacy of treatment, whether with _____, ____________________ drugs or _____________ alone, can be assessed clinically and by measurements of blood glucose concentration, both in the clinic and by patients.
insulin
oral hypoglycaemic
dietary modification
Complications of DM
Measurements of ____________(HbA1c) provide a valuable index of ___________ over a period of _______
glycated haemoglobin (HbA1c)
glycaemic control
three months
Gestationnal DM
Maternal diabetes increases the risk of ___________ and unexplained fetal death.
This risk can be greatly reduced by ensuring ________ at conception and during ________
congenital malformations
good glycaemic control
early pregnancy
Gestationnal DM
Maternal hyperglycaemia increases ______ secretion and can cause fetal ________, predisposing to difficult ____ and neonatal _________.
fetal insulin
macrosomia
delivery; hypoglycaemia
Gestationnal DM
Pregnancy causes ————- especially in the _______________ trimesters of pregnancy
insulin resistance
2nd and 3rd
Gestationnal DM
Risks factors
_______ ;_______
Advanced ______
Past _________
____uria
High risk patients require testing – age > ____yrs, PCOS, obesity
Family history ; Obesity
macrosomic baby ; Glycos
25
Testing
One step approach –____ of glucose given irrespective of initial fast or not
100g
Testing
2 step approach –_____ glucose given irrespective of initial fast or not
if serum glucose concentration is > _____ mg/dl, then proceed to the 2nd stage of testing whish is the _______ with _____ or _____ glucose:
1hr – _____ mg/dl
2hr – ____ mg/dL
3hr – ____ mg/dL
50g; 140
OGTT test
75g or 100g
180; 155; 140
