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Bio 66 > Chapter 19 Regulation of Metabolism > Flashcards

Chapter 19 Regulation of Metabolism Flashcards

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Biology 101 flashcards
1
Q

What is energy stored as

A

Glycogen and fat

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2
Q

What regulates the usage of energy stores

A

hormones

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3
Q

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

A 
Absorptive state (feasting):
Postabsorptive state
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4
Q

What is absorptive state

A

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

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5
Q

What is Postabsorptive State

A

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

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6
Q

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

A

Glucagon and insulin

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7
Q

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

A

Glucagon

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8
Q

What do the Beta cells of pancreatic islets secrete

A

insulin

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9
Q

What happens with insulin

A

Increased secretion during absorptive state, when blood glucose is high

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

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10
Q

What happens with Glucagon

What does it stimulate

A

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)

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11
Q

Carbohydrates are absorbed into the blood from the GI tract as

What does insulin do

A

Monosaccarhrides

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

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12
Q

Proteins are absorbed into the blood from the GI tract as

What does insulin do

A

AAs

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

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13
Q

Fats are absorbed into lymph as

What does insulin do

A

Chylomicrons

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

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14
Q

What is the overall impact of the absorptive state

A

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

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15
Q

Where does the absorptive state mainly occur

A

skeletal muscles

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16
Q

What is the bodies main energy source

A

Glucose

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17
Q

Glucose can enter the liver to do what (2)

A

Be stored as glycogen

Be used to synthesize triglycerides

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18
Q

What is cholesterol a component of

What happens when there is excess

A

Plasma membranes
Precursor for bile salts
Steroid hormones

Excess = atherosclerosis

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19
Q

Where are AA used for and absorbed into

A

Liver
Used for synthesise of proteins

Deaminated = amino group removed

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20
Q

What happens when deamination occurs

A

The amino group is used to synthesize urea

The remainder is catabolized to provide energy for liver cells

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21
Q

What occurs in postabsorptive state

A

Synthesis of glycogen, triglycerides and proteins stops

Catabolism of stores occurs due to secretion of glucagon

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22
Q

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

A

Glycogenolysis
Gluconeogensis
Glucose sparing
Ketogensis

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23
Q

What is Glycogenolysis

A

Hydrolysis of glycogen in liver to increase blood glucose

24
Q

What is Gluconeogenesis

A

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

25
Q

What is Glucose sparing

A

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

26
Q

What is Ketogenesis

Where does it occur

A

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

Occurs in the liver

27
Q

What happens during fasting (4)

A

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

28
Q

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

A

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
29
Q

What is Anabolism

A

Synthesis of energy reserves

30
Q

What is Catabolism

A

Utilisation of energy reserves

31
Q

Feasting vs Fasting

Process
Fuel
Storage

A

Feasting:

  1. Anabolism
  2. Fuel is glucose
  3. Storage molecules

Fasting:

  1. Catabolism
  2. Diverse fuels
  3. Gluconeogenesis
32
Q

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
A
  1. Increase
  2. decrease
  3. increase
  4. Formation of glycogen, fat and protein
  5. increase
33
Q

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
A
  1. Decreases
  2. Increases
  3. Decreases
  4. Hydrolysis of glycogen, fat and protein. Gluconeogenesis and ketogenesis
  5. Increase
34
Q

What are the two types of diabetes mellitus

A

Type 1 = Insulin dependent

Type 2 = Non - insulin dependent

35
Q

What is diabetes mellitus

A

Chronic high blood glucose, hyperglycemia

36
Q

What is type 1 diabetes mellitus

What must we do to treat it

A

Insulin deficiency due to autoimmune destruction of beta cells

So insulin must be injected, pumped, or inhaled in powder form

37
Q

Type 1 diabetes mellitus causes

A
  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
38
Q

Why does Hyperglycemia occur in type 1

A

Because glucose doesn’t enter cells

39
Q

Why does Glucosuria occur in type 1

A

Because amount of glucose exceeds transport maximum for reabsorption in kidneys

40
Q

Why does Ketosis occur in type 1

A

Ketone body concentration is elevated

Because increased lipolysis releases fatty acids, which are converted to ketone bodies

41
Q

Why is there an increase in glucagon in type 1

A

Glycogenolysis in liver and conversion of fatty acids into ketone bodies

42
Q

Why does ketoacidosis occur in type 1

A

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

43
Q

Why is there an excessive excretion of water in urine

A

Excessive glucose and ketone bodies in urine cause osmotic diuresis

44
Q

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

A

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

45
Q

What is type 2 diabetes mellitus

A

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

46
Q

Why is type 2 diabetes common in obese people

A

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

47
Q

What are the effects of diabetes (4)

A
  1. Tissue damage
  2. Damage to capillaries
  3. Decreased sensation in the extremities
  4. Circulatory deficiencies = feet infections etc
48
Q

Where does dietary cholesterol enter

Where does it then travel

What results in its second location

A

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

49
Q

The liver synthesises cholesterol?

A

True

50
Q

What are the functions of cholesterol (6)

A
  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
51
Q

VLDLs are

Where are they secreted

A

Cholesterol + triglycerides + proteins

Secreted into the blood to deliver triglycerides to organs

52
Q

What are LDL

How are they made

Where is it carried

A

Bad cholesterol

Made when triglycerides are removed from VLDLs

Carries cholesterol to organs including blood vessels

53
Q

What are HDLs

A

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

54
Q

What hormone is necessary for long term regulation of food intake

A

Leptin

55
Q

What happens when there is a release of leptin

A

Acts on hypothalamus to decrease food intake and increase metabolic rate

56
Q

Appetite is controlled by…

A

A diverse set of inputs

Bio 66 (22 decks)

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