Chapter 19 Regulation of Metabolism

Question 1

What is energy stored as

Answer 1

Glycogen and fat

Question 2

What regulates the usage of energy stores

Answer 2

hormones

Question 3

What are the two functional states for providing energy for cellular activity and maintaining blood glucose concentration

Answer 3

Absorptive state (feasting):
Postabsorptive state

Question 4

What is absorptive state

Answer 4

When ingested nutrients enter the blood from the GI tract during the 4 h period following a meal

Question 5

What is Postabsorptive State

Answer 5

After the absorptive state, when the GI tract is empty of nutrients and the body’s own stores supply energy

Question 6

What hormones control the transition between fasting and feasting, and maintain glucose homeostasis.

Answer 6

Glucagon and insulin

Question 7

What do the Alpha cells of pancreatic islets (islets of Langerhans) secrete

Answer 7

Glucagon

Question 8

What do the Beta cells of pancreatic islets secrete

Answer 8

insulin

Question 9

What happens with insulin

Answer 9

Increased secretion during absorptive state, when blood glucose is high

Metabolic effects in muscle, adipose (fat) tissue, and liver for synthesis of energy reserves

Question 10

What happens with Glucagon

What does it stimulate

Answer 10

Increased secretion during postabsorptive state, when blood glucose is low which increases plasma concentration of glucose and ketones

Stimulates breakdown of glycogen by liver and skeletal muscles (glycogenolysis), production of glucose by liver and kidneys (gluconeogenesis) and ketone synthesis by liver (ketogenesis)

Question 11

Carbohydrates are absorbed into the blood from the GI tract as

What does insulin do

Answer 11

Monosaccarhrides

Promotes cellular uptake of glucose, and storage of glucose as glycogen in liver and muscles (anabolism).

Question 12

Proteins are absorbed into the blood from the GI tract as

What does insulin do

Answer 12

AAs

Promotes cellular uptake of AAs and their incorporation into proteins (anabolism).

Question 13

Fats are absorbed into lymph as

What does insulin do

Answer 13

Chylomicrons

Promotes conversion of lipids + glucose into triglycerides to be stored in adipose tissue (anabolism)

Question 14

What is the overall impact of the absorptive state

Answer 14

To increase stores and decrease high plasma concentration of glucose and AAs

Question 15

Where does the absorptive state mainly occur

Answer 15

skeletal muscles

Question 16

What is the bodies main energy source

Answer 16

Glucose

Question 17

Glucose can enter the liver to do what (2)

Answer 17

Be stored as glycogen

Be used to synthesize triglycerides

Question 18

What is cholesterol a component of

What happens when there is excess

Answer 18

Plasma membranes
Precursor for bile salts
Steroid hormones

Excess = atherosclerosis

Question 19

Where are AA used for and absorbed into

Answer 19

Liver
Used for synthesise of proteins

Deaminated = amino group removed

Question 20

What happens when deamination occurs

Answer 20

The amino group is used to synthesize urea

The remainder is catabolized to provide energy for liver cells

Question 21

What occurs in postabsorptive state

Answer 21

Synthesis of glycogen, triglycerides and proteins stops

Catabolism of stores occurs due to secretion of glucagon

Question 22

What are the different ways for Homeostasis of blood glucose (4)

Answer 22

Glycogenolysis
Gluconeogensis
Glucose sparing
Ketogensis

Question 23

What is Glycogenolysis

Answer 23

Hydrolysis of glycogen in liver to increase blood glucose

Question 24

What is Gluconeogenesis

Answer 24

Synthesis of glucose using AAs (from skeletal muscle), glycerol, pyruvate, and lactate, in liver and kidneys

Question 25

What is Glucose sparing

Answer 25

Most tissues (except nervous) can use free fatty acids from lipolysis for energy instead of glucose

Question 26

What is Ketogenesis Where does it occur

Answer 26

Synthesis of ketone bodies from fatty acids, used as an alternative energy source during prolonged fasting Occurs in the liver

Question 27

What happens during fasting (4)

Answer 27

Insulin secretion decreases Glucagon secretion increases Release of glucose, fatty acids, ketone bodies, and AAs into the blood Liver also releases glucose synthesized by gluconeogenesis

Question 28

What are the two ways of the neuronal regulation of pancreatic islets How does each way either stimulate or inhibit GI function and insulin secretion

Answer 28

Parasympathetic: 1. During meals 2. Stimulates GI function 3. Stimulates insulin secretion from beta cells Sympathetic 1. E and NE inhibit GI function 2. Inhibit insulin secretion 3. Stimulate glucagon secretion from alpha cells

Question 29

What is Anabolism

Answer 29

Synthesis of energy reserves

Question 30

What is Catabolism

Answer 30

Utilisation of energy reserves

Question 31

Feasting vs Fasting Process Fuel Storage

Answer 31

Feasting: 1. Anabolism 2. Fuel is glucose 3. Storage molecules Fasting: 1. Catabolism 2. Diverse fuels 3. Gluconeogenesis

Question 32

During the absorption of a meal (feasting) what happens to: 1. Insulin 2. Glucagon 3. Insulin/glucagon ratio 4. What happens to glycogen, fat and protein 5. Blood: Glucose, AA, FAs, Ketone bodies

Answer 32

1. Increase 2. decrease 3. increase 4. Formation of glycogen, fat and protein 5. increase

Question 33

During fasting what happens to: 1. Insulin 2. Glucagon 3. Insulin/glucagon ratio 4. What happens to glycogen, fat and protein 5. Blood: Glucose, AA, FAs, Ketone bodies

Answer 33

1. Decreases 2. Increases 3. Decreases 4. Hydrolysis of glycogen, fat and protein. Gluconeogenesis and ketogenesis 5. Increase

Question 34

What are the two types of diabetes mellitus

Answer 34

Type 1 = Insulin dependent Type 2 = Non - insulin dependent

Question 35

What is diabetes mellitus

Answer 35

Chronic high blood glucose, hyperglycemia

Question 36

What is type 1 diabetes mellitus What must we do to treat it

Answer 36

Insulin deficiency due to autoimmune destruction of beta cells So insulin must be injected, pumped, or inhaled in powder form

Question 37

Type 1 diabetes mellitus causes

Answer 37

1. 3 Ps: Polyuria Polyphagia Polydipsia 2. Prolong fasting 3. Hyperglycemia 4. Glucosuria 5. Ketosis 6. Excessive excretion of water in urine 7. Increase glucagon 8. Ketoacidosis

Question 38

Why does Hyperglycemia occur in type 1

Answer 38

Because glucose doesn’t enter cells

Question 39

Why does Glucosuria occur in type 1

Answer 39

Because amount of glucose exceeds transport maximum for reabsorption in kidneys

Question 40

Why does Ketosis occur in type 1

Answer 40

Ketone body concentration is elevated Because increased lipolysis releases fatty acids, which are converted to ketone bodies

Question 41

Why is there an increase in glucagon in type 1

Answer 41

Glycogenolysis in liver and conversion of fatty acids into ketone bodies

Question 42

Why does ketoacidosis occur in type 1

Answer 42

If there is not enough bicarbonate to neutralise acid from ketone bodies

Question 43

Why is there an excessive excretion of water in urine

Answer 43

Excessive glucose and ketone bodies in urine cause osmotic diuresis

Question 44

What happens when there is a failure to secrete insulin (2)

Answer 44

There is a shift in metabolic dependence to acid generating ketones In addition, hyperglycemia induced diuresis reduces blood volume to the point of hypotension and inadequate blood delivery to the brain

Question 45

What is type 2 diabetes mellitus

Answer 45

Insulin is present but target cells are resistant to insulin, and beta cells may secrete more insulin in response to glucose

Question 46

Why is type 2 diabetes common in obese people

Answer 46

Insulin sensitivity is reduced by the presence of excess adipose tissue cells

Question 47

What are the effects of diabetes (4)

Answer 47

1. Tissue damage 2. Damage to capillaries 3. Decreased sensation in the extremities 4. Circulatory deficiencies = feet infections etc

Question 48

Where does dietary cholesterol enter Where does it then travel What results in its second location

Answer 48

The GI tract Enters in plasma of chylomicrons in SI Chylomicrons travel to liver, cholesterol is secreted into bile and catabolised into bile salts Bile then enters GI tract for breakdown of fats via lipase

Question 49

The liver synthesises cholesterol?

Answer 49

True

Question 50

What are the functions of cholesterol (6)

Answer 50

1. Membranes 2. Basis for steroids + bile salts 3. Found in chylomicrons 4. Combined to form VLDLs in liver 5. Found in LDLs 6. Found in HDL

Question 51

VLDLs are Where are they secreted

Answer 51

Cholesterol + triglycerides + proteins Secreted into the blood to deliver triglycerides to organs

Question 52

What are LDL How are they made Where is it carried

Answer 52

Bad cholesterol Made when triglycerides are removed from VLDLs Carries cholesterol to organs including blood vessels

Question 53

What are HDLs

Answer 53

Excess cholesterol from organs attaches to HDL to return to the liver

Question 54

What hormone is necessary for long term regulation of food intake

Answer 54

Leptin

Question 55

What happens when there is a release of leptin

Answer 55

Acts on hypothalamus to decrease food intake and increase metabolic rate

Question 56

Appetite is controlled by...

Answer 56

A diverse set of inputs