Lecture 21- Metabolic and Endocrine control during special circumstances

Question 1

Major metabolic fuel sources?

Answer 1

Glucose,and fatty acids normally available while ketone bodies, lactate and amino acids available under special circumstances

Question 2

Where do ketone bodies come from?

Answer 2

Mainly from fatty acids and can be used by brain when critically short

Question 3

How can lactate be a fuel source?

Answer 3

Through cori cycle can be converted to glucose

Question 4

Energy stores?

Answer 4

Glycogen, fat, muscle protein

Question 5

Metabolic control?

Answer 5

For two hours after feeding glucose and fatty acids available. Make glycogen and increase fat stores.

8-10 hours glycogen used to make glucose.cfatty acids used and blood glucose preserved for brain

Another 8-10 hours and glycogen deplete so use amino acids, glycerol and lactate

Any time after this ketone bodies produced from fatty acids to supply brain

Question 6

Starvation?

Answer 6

Ketone bodies produced by liver

Cortisol and glucagon secreted which cause gluconeogenesis and breakdown of protein and fat

Reduced insulin and increased cortisol prevents cells from using glucose and fatty acids used instead

When fat used up protein used. Muscle wasting leads to death

Question 7

Referring syndrome?

Answer 7

Be careful of it after starvation

Question 8

When does most foetal growth occur?

Answer 8

Two thirds in the last third of pregnancy

Question 9

Early pregnancy?

Answer 9

Mother anabolic state increase fat and small increase insulin sensitivity

Question 10

Late pregnancy?

Answer 10

Catabolic. Decreased insulin sensitivity means that glucose soared for foetus and fatty acids used by mother instead

Question 11

What is placenta, foetal adrenals and liver known as?

Answer 11

Fetoplacental unit

Placenta secretes wide range of proteins that can control maternal hypothalamic pituitary axis

Question 12

How are nutrient concentrations kept high in latter stages of pregnancy?

Answer 12

Reducing glucose utilisation

Delaying maternal disposal of nutrients

Releasing fatty acids from stores

Question 13

Placental anti insulin hormones?

Answer 13

Progesterone

Human placental lactogen

CRH

Question 14

Consequences to mother of decreased insulin/anti insulin ratio?

Answer 14

Transient hyperglycaemia after meals due to insulin resistance and hypoglycaemia between meals and at night due to foetus drawing glucose

Question 15

What causes gestational diabetes?

Answer 15

More glucose is consumed

Oestrogen and progesterone increase sensitivity of pancreatic beta cells to blood glucose causing hyperplasia and hypertrophy. Insulin resistance can also occur

If this doesn’t occur can get gestational diabetes

Question 16

Clinical implications of gestational diabetes?

Answer 16

Miscarriage 
Congenital malformation 
Macrosomia
Shoulder dystocia 
Gestational hypertension and preeclampsia

Question 17

How to determine if woman likely to get gestational diabetes?

Answer 17

Depends on starting point. Insulin resistance increases with age. If already relatively high then pregnancy could push it over. Likely to get diabetes in future

Question 18

Gestational diabetes risk factors?

Answer 18

BMI over 25
Maternal age over 25
Race 
Family history diabetes 
Family history macrosomia

Question 19

How to manage gestational diabetes?

Answer 19

Give insulin

Diet modifications

Ultrasound to assess foetus

Question 20

Energy requirements of exercise and ATP?

Answer 20

ATP stores last two seconds and must be replenished. Mechanism of replenishment will depend on exercise intensity

Question 21

Initial ATP?

Answer 21

Creating phosphate converted to creative through creative kinase.

Question 22

Where does ATP come from after creative kinase?

Answer 22

Glycolysis if anaerobic and oxidative phosphorylation if aerobic

Question 23

Muscle glycogen

Answer 23

Anaerobic 2 ,inure supply

Aerobic 1 hour supply

Lactate from anaerobic can be converted to glucose through cori cycle

Question 24

Organ responsible for regulating blood glucose?

Answer 24

Liver

Question 25

Interesting fact about muscle and exercise?

Answer 25

Has insulin independent glucose uptake mechanism stimulated by AMP

Question 26

Fatty acids as fuel?

Answer 26

Only used in aerobic conditions
48 hrs low intensity
Release on uptake through carnations shuttle of mitochondria

Question 27

100m race?

Answer 27

Once high energy phosphate stores used after 5 seconds must create ATP anaerobically through muscle glycogen. Lactate produced

Question 28

1500m?

Answer 28

40% anaerobic metabolism

Initially creatine phosphate and anaerobic glycogen

Then aerobic using muscle glycogen

Question 29

Marathon?

Answer 29

95% aerobic

Uses muscle glycogen, liver glycogen and fatty acids

Muscle glycogen lasts a few minutes, liver peaks at an hour, fatty acid use rises steadily from 30 mins

Blood glucose lowers continually

Question 30

Hormones over marathon?

Answer 30

Insulin decreases, glucagon, adrenaline, growth hormone and cortisol rise

Gluconeogenesis, lipolysis etc activated

Question 31

Exercise benefits?

Answer 31

Increased insulin sensitivity

Increased muscle and reduced fat

Lower blood triglycerides so less vldl, ldl and higher hdl

Lower BP

Increased glucose tolerance

Feeling of well being