Disorders of carbohydrate metabolism Flashcards by Iseoluwa Ojo

Carbohydrates (CHO)

Source of energy for the body
Essential energy for some tissues like _____ and ______

brain and RBC

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Carbohydrates (CHO)

Exist as
Polysaccharides – ____,_______

Disaccharides – _____,______

Monosaccharides – _______,________

Starch, Glycogen

Lactose, sucrose

Glucose, Fructose

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Carbohydrates (CHO)

Complex CHO taken as food are digested to _______ which are then absorbed in the intestines

monosaccharides

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_______ is the most used monosaccharide as metabolic fuel

Glucose

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Many tissues are capable of ______ glucose completely to ______

Oxidizing

carbon dioxide

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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

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Tissues capable of completely oxidizing glucose, ______ is produced if insufficient oxygen is available (_________ metabolism)

lactate

anaerobic

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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

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Glycogen is stored in the ______ and ________ , but only the former contributes to blood glucose.

liver and skeletal muscle

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Regulation of blood glucose

Blood glucose concentration depends on the _____________________

influx of glucose into circulation and use

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Regulation of blood glucose

Homeostatic mechanisms maintains blood glucose around ____-____mg/dL.

50 -110 mg/dL.

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Regulation of blood glucose

The _______ produces hormones that regulate blood glucose concentration

pancreas

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Pancreatic hormones that affects glucose

List 3

Glucagon

Insulin

Somatostatin

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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

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Pancreatic hormones

Other hormones – (Aid or Counter?) insulin action: _____,______hormones, _______,________ hormone, _____

Counter Epinephrine

thyroid

Cortisol

Growth; ACTH

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Pancreatic hormones

Two most important hormones in glucose homoeostasis are ______ and _____

insulin and glucagon.

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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

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Insulin

It is synthesized as a _______,________.

This molecule undergoes ______ prior to secretion to form insulin and _______

prohormone, proinsulin

cleavage

C-peptide.

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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

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Incretin release is stimulated by ______, so that _______ begins to increase before blood ________

food

insulin secretion

glucose concentration.

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Biosynthesis of insulin

The cleavage of ________ produces insulin, consisting of two polypeptide chains linked by ________, and _________

proinsulin

disulphide bridges

C-peptide.

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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.

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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

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Insulin stimulates glycogen _______ (and inhibits glycoge______)

synthesis

nolysis

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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

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