Flashcards in Nutrition and Energy Balance pt 2 Deck (98)
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1
Q

What are the exocrine cells of the pancreas called?

A

Acinar cells

2
Q

Do pancreatic islets contain endocrine or exocrine cells?

A

Endocrine

3
Q

Alpha cells produce what?

A

Glucagon

4
Q

Beta cells produce what?

A

Insulin

5
Q

When is insulin secreted?

A

Blood glucose levels increase, blood levels of AAs and FAs increase, ACh is released by parasympathetic nerve fibers

6
Q

What is insulin first synthesized as?

A

Proinsulin

7
Q

What are the three ways that insulin lowers blood glucose?

A

Enhance membrane transport of glucose into fat and muscle cells, inhibit breakdown of glycogen, inhibit conversion of AAs and fats to glucose

8
Q

What is the net effect of insulin?

A

Lower blood glucose and AAs and FFAs, increased glycogen storage

9
Q

What is glucagon triggered by?

A

Decreased blood glucose, rising AA levels, sympathetic NS

10
Q

How does the liver use glucagon to raise blood glucose levels?

A

Glycogen into glucose, synthesize glucose from lactic acid and other noncarbs, release glucose into blood

11
Q

What is the net effect of glucagon?

A

Increased blood glucose and blood AAs and FFAs, decreased glycogen storage

12
Q

Diabetes mellitus is characterized by what?

A

High levels of blood glucose from defects in insulin production, insulin action, or both. Complex disorders of CHO, fat and protein metabolism.

13
Q

What is the difference between type 1 and type 2 diabetes?

A

Type 1 there is an absolute insulin deficiency, type 2 is insulin resistance

14
Q

Which is more common, type 1 or type 2 diabetes?

A

Type 2 (90%) compared to type 1 (10%)

15
Q

What are the consequences of insulin deficiency (diabetes)?

A

Decreased uptake of glucose by peripheral tissue, increased glucose production (gluconeogenesis) and increased release of glucose from the liver (glycogenolysis)

16
Q

In type 1 diabetes, fats can be used as fuel which can cause _______: high levels of fatty acids in blood

A

Lipidemia

17
Q

Fatty acid metabolism (lipolysis), as seen in type 1 diabetes, results in the formation of what energy source:

A

Ketones

18
Q

List 3 risk factors for type 2 diabetes

A

Age, obesity, hypertension, inactivity, family history

19
Q

What are some consequences of obesity related to type 2 diabetes?

A

Adipose tissue secrete hormones that decrease insulin sensitivity, increased FFAs and cholesterol, increase in inflammatory cytokines that cause insulin resistance and are toxic to beta cells

20
Q

What are the cells of the liver called?

A

Hepatocytes- they carry out around 500 metabolic functions

21
Q

What are some of the roles of the liver in metabolism?

A

Process every class of nutrient, regulate plasma cholesterol levels, store vitamins and minerals, metabolize alcohol, drugs, hormones, and bilirubin

22
Q

Is cholesterol used as an energy source?

A

No

23
Q

What is cholesterol used for?

A

Structural basis for bile salts, steroid hormones, vitamin D, major component of plasma membranes

24
Q

__% of cholesterol is ingested and the rest is made in the liver

A

15

25
Q

What molecule transports cholesterol through blood?

A

Lipoprotein

26
Q

VLDLs have very low density, which means they have more/less lipids?

A

More

27
Q

What are the four types of transport lipoproteins?

A

HDLs, LDLs, VLDLs, chylomicrons

28
Q

What is the role of chylomicrons?

A

To carry absorbed lipids from intestine to liver

29
Q

What is the role of VLDLs?

A

To carry TGs from liver to peripheral tissues, mostly to adipose tissue

30
Q

What is the role of LDLs?

A

To carry cholesterol from liver to tissues

31
Q

What is the role of HDLs?

A

To carry cholesterol from tissues to liver

32
Q

What is the ideal recommended cholesterol levels in Canada?

A

Less than 5.2mml/L is ideal, more than 6.2 is high

33
Q

What is the ideal HDL intake levels in canada?

A

More than 0.9mmol/L

34
Q

What is the ideal LDL intake levels in canada?

A

Less than 3.5mmol/L is ideal, more than 4.0 is high

35
Q

True or false: the liver produces more cholesterol if you do not ingest enough

A

False. Produces cholesterol at a basal level regardless of dietary intake.

36
Q

Which fatty acid, saturated or unsaturated, enhances excretion of cholesterol into bile salts?

A

Unsaturated. Saturated fat stimulates liver synthesis of cholesterol and inhibits cholesterol excretion

37
Q

What are the effects of trans fat on the levels of lipoproteins?

A

Increase LDL, reduce HDL

38
Q

What are three effects of unsaturated omega-3 fatty acids to lower the proportion of saturated fats and cholesterol?

A

Make platelets less sticky and help prevent spontaneous clotting, have antiarrhythmic effects on the heart, can lower blood pressure

39
Q

Fat carried on the upper body, also known as an apple body shape, correlates with what?

A

High cholesterol and LDL levels

40
Q

Follicles, found in the thyroid gland, produce which glycoprotein?

A

Thyroglobulin

41
Q

Parafollicular cells produce which hormone?

A

Calcitonin

42
Q

True or false: the thyroid hormone is the body’s major metabolic hormone

A

True

43
Q

T4 (Thyroxine), is the major form of the thyroid hormone and is bound to _ iodine atoms

A

4

44
Q

What are some of the effects of the thyroid hormone?

A

Increase basal metabolic rate and heat production (calorigenic effect), regulate tissue growth and development, maintain BP

45
Q

Where are T3 and T4 stored?

A

Follicles lumen until triggered to release by TSH

46
Q

What molecule transports thyroid hormone?

A

Thyroxine-binding globulins

47
Q

Falling thyroid hormone levels stimulate the release of thyroid-stimulating hormone. This is a positive/negative feedback mechanism.

A

Negative

48
Q

Hypothalamic thyrotropin-releasing hormone (TRH) can overcome the negative feedback mechanism of TH during:

A

Pregnancy or exposure to cold

49
Q

What causes myxedema? How can a goiter develop?

A

TH Hyposecretion; lack of iodine

50
Q

In infants, hyposecretion of TH can cause:

A

cretinism

51
Q

Hypersecretion of thyroid hormone can cause what?

A

Grave’s disease

52
Q

What proportion of energy is immediately lost as heat?

A

60%

53
Q

Almost all energy from food is eventually converted to heat which is useful because:

A

It warms tissues and blood, helps maintain homeostatic body temp, allows metabolic reactions to occur efficiently

54
Q

What is the BMI formula?

A

BMI= weight (in kg)/height (in m^2)

55
Q

Name 3 diseases/consequences that have an increased incidence as a result of obesity:

A

Atherosclerosis, diabetes, hypertension, heart disease, osteoarthritis

56
Q

What is the proportion of adults that are overweight?

A

2/3

57
Q

What is the proportion of adult overweight individuals who are obese?

A

1/3

58
Q

What is the proportion of diabetes in obese individuals?

A

1/10

59
Q

What are the five risk factors of metabolic syndrome?

A
  1. Increased waist circumference
  2. Increased BP
  3. Increased blood glucose
  4. Increased blood triglycerides
  5. Decreased HDL cholesterol
60
Q

The presence of risk factors associated with metabolic syndrome can result in what?

A

Double the chance of heart disease, increase the risk of diabetes 5x

61
Q

The _________ plays an important role in regulating food intake

A

Hypothalamus

62
Q

What are the three areas of the hypothalamus that release peptides to influence feeding behaviour?

A

Arcuate nucleus (ARC), lateral hypothalamic area (LHA), ventromedial nucleus (VMN)

63
Q

Some ARC neurons release _________ that enhance appetite

A

Neuropeptide Y (NPY)

64
Q

Some ARC neurons release _________ and _________ which suppress appetite.

A

Pro-opiomelanocortin (POMC) and cocaine-amphetamine-regulated transcript (CART)

65
Q

The LHA increases/decreases hunger when stimulated by neuropeptides

A

Increases

66
Q

VMN increases/decreases hunger through release of corticotropin-releasing hormone (CRH) when stimulated by appetite-suppressing peptides (POMC and CART)

A

Decrease

67
Q

List 3 ways that feeding behaviour and hunger is regulated by:

A

Neural signals from GI tract, bloodborne signals related to body energy stores, hormones, body temperature, psychological factors. Additional factors in regulation of food intake include: temperature (cold activates hunger), stress, adenovirus infections, sleep deprivation, composition of gut bacteria.

68
Q

True or false: Food intake is regulated by short and long-term controls.

A

True

69
Q

How do neural signals from the digestive tract regulate food intake?

A

High protein content of meal increases and prolongs afferent vagal signals-> sends signals along vagus nerve to suppress hunger center

70
Q

Name 2 hormones that stimulate hunger

A

Glucagon, epinephrine, ghrelin (

71
Q

Name 2 hormones that depress hunger

A

Insulin, CCK

72
Q

What hormone is the major component of long-term regulation of food intake?

A

Leptin

73
Q

Leptin is secreted by what type of cells?

A

Fat cells, in response to increased body fat mass

74
Q

What are some of the roles of leptin?

A

Protects against weight loss in times of nutritional deprivation, acts on ARC neurons in hypothalamus, suppresses secretion of NPY (potent appetite stimulant), stimulates expression of appetite suppressants

75
Q

True or false: Obese people have high leptin levels

A

True, but they seem resistant to its action

76
Q

Metabolic rate is defined as:

A

Total head produced by chemical reactions and mechanical work of body

77
Q

What tool is used to measure metabolic rate directly?

A

Calorimeter

78
Q

What tool is used to measure metabolic rate indirectly?

A

Respirometer

79
Q

Basal metabolic rate can be defined as:

A

Energy body needs to perform its most essential activities

80
Q

List 3 ways that basal metabolic rate is influenced by

A

Age, gender, body temp, stress, thyroxine.

BMR decreases with age; males have higher BMR; BMR increases with temp and stress; thyroxine increases O2 consumption and BMR

81
Q

Total metabolic rate is defined as:

A

Rate of kilocalorie consumption to fuel all ongoing activities. Can be considered as daily energy expenditure.

82
Q

What are the three components of total metabolic rate?

A

Basal energy expenditure, thermic effect of food, energy expended on physical activity

83
Q

True or false: At rest, most heat is generated from muscles

A

False: Liver, heart, brain, kidneys, and endocrine organs.

84
Q

What is normal body temperature?

A

37 degrees celsius +/- 5 degrees (98.6F)

85
Q

True or false: Tissues can tolerate low temperatures better than high temperatures

A

True

86
Q

What is the temperature that is the limit for life?

A

Around 43 degrees celsius

87
Q

True or false: Taking temperature via the mouth is the best clinical indicator

A

False: rectum

88
Q

What are the four mechanisms of heat transfer?

A

Radiation, conduction, convection, evaporation

89
Q

What is insensible heat loss?

A

Water loss from lungs, oral mucosa, and skin

90
Q

What region of the hypothalamus is the main integrating center for thermoregulation?

A

Preoptic region

91
Q

Hypothalamus receives afferent input from which thermoreceptors?

A

Peripheral (skin) and central (core)

92
Q

List 3 heat-promoting mechanisms

A

Putting on more clothes, drinking hot fluids, changing posture, increasing physical activity.

Constriction of cutaneous blood vessels (sympathetic NS), shivering, increases in metabolic rate (epinephrine and norepinephrine, brown adipose tissue), enhanced release of thyroxine

93
Q

List 3 heat-loss mechanisms

A

Wearing light-coloured, loose-fitting clothing, take off sweater, turn on fan, cold drink, reduce activity, seek cooler environment, dilation of cutaneous blood vessels, enhanced sweating

94
Q

Why does vasoconstriction promote heat?

A

Less blood flow to skin where heat loss is likely to occur

95
Q

In hypothermia, at what temperature does shivering stop? What temperature can lead to coma and death by cardiac arrest?

A

30-32 degrees celsius; around 21 degrees celsius

96
Q

In hyperthermia, at what temperature can a heat stroke begin?

A

41 degrees celsius

97
Q

What causes heat exhaustion?

A

Vigorous exercise, dehydration, low BP

98
Q

How does the hypothalamus increases the set-point of the body temperature?

A

Macrophages release cytokines called pyrogens that release prostaglandins from the hypothalamus