Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Phys II Unit II > 7 Fat > Flashcards

7 Fat Flashcards

1
Q

What is the “old view” of fat?

A

Fat is a passive organ that is a DEPOT for fat storage

“Fat” refers to lipids and cells/tissues that store lipids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the “modern view” of fat?

A

Fat is a DYNAMIC organ

Energy conversion and storage
Regulates energy balance and nutritional homeostasis
Generates heat (“brown fat”)
Cushions organs
Affects body shape and appearance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is adiposity?

A

How fat deposition occurs in the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How is BMI calculated?

A

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

Or

BMI = weight (lbs) x 703 / height (inches^2)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

BMI>30

A

Obese

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

BMI = 25-29.5

A

“Overweight”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

BMI = 18.5 - 24.9

A

Health lean

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

BMI<18.5

A

Underweight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What happens to BMI with age?

A

Increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the definition of obesity

A

Clinical state of excessive accumulation of body fat

Usually based upon BMI (>30)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The condition of abnormal lipid levels and/or their lipoproteins

A

Dyslipidemia or hyperlipidemia

Can be elevated cholesterol and triglycerides or elevated chylomicrons and LDL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

White adipose tissue can be subdivided into …

A

Visceral vs subcutaneous white adipose tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which is more dangerous: visceral or subcutaneous fat

A

Visceral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Obesity is associated with…

A

Heart disease
Stroke
Diabetes
Cancers

36.5% of US adults are obese

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What groups are disproportionally obese?

A

Non-Hispanic blacks (48.1%)

Middle age (40.2% vs young adults 32.3%)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the three types of adipocytes?

A

White, Brown, Beige

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the two types of fat deposits?

A

White adipose tissue (WAT)

Brown adipose tissue (BAT)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What types of cells are found in WAT?

A

Adipocytes (~50% of cells)
Pre-adipocytes (~2% of cells) - these are adipo stem cells
Fibroblasts - connective tissue
Endothelial cells - circulatory
Nerve cells
Macrophages (M1 pro-inflammatory vs M2 anti-inflammatory)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Brown fat is a _______ organ

A

Heat-generating

Hormone dependent - requires UCP1 transcription and G-protein second messenger

Daily heat production: 27 kcal/kg body weight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What allows brown adipose tissue to directly transfer food energy into heat energy?

A

Uncoupling Protein 1 (UCP1)

Dependent upon both Epi and TSH

T4 enters, converted to T3, binds to receptor and transcription —> UCP1 production; UCP1 enters mitochondria and generates heat.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Brown fat is found predominantly in _______.

A

Infants

It decreases with age but adults still have some concentrated around neck, shoulders, lungs (F>M)

BAT contains numerous small lipid droplets, uncoupled mitochondria, and myoglobin

BAT activity can be increased in response to cold exposure or epi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is Beige Fat?

A

Occurs in WAT, has INTERMEDIATE mitochondria, UCP1 and lipid droplets, heat production compared to BAT

Possible induction by T3 and epi, cold, hepatic bile acids, and ANP/BNP, skeletal muscle hormone Irisin

23
Q

What hormone promotes storage of fats into adipocytes and stimulates anti lipolysis effect (FA—>TG)?

A

Insulin

Stimulates lipoprotein lipase to convert TG to FA
Stimulates GLUT4 to increase glucose uptake into adipocytes
Inhibits hormone-sensitive lipase

Results:
Lower fatty acids and increased storage
Increased glucose uptake into adipocytes
Increased enzymes that produce fatty acids
Increased fatty acid uptake
Decreased lipolysis
24
Q

What hormones stimulate a lipolysis effect (TG —> FA)?

A

Epinephrine, cortisol, glucagon, and GH

Epi acts via HSL and adipose tissue triglyceride lipase (ATGL)

Thyroid hormone also has some indirect effect:
Doesn’t directly regulate fuel metabolites b/c onset is too slow to rapidly adjust blood levels of nutrients

25
Q

Women tend to have more ________ fat depots, whereas men tend to have more ________ fat depots

A

Women = Subcutaneous (Gynecoid Adiposity)
Blood drains to skeletal muscle and free fatty acids are utilized for energy during exercise

Men = Visceral (Android Adiposity)
Mental and messenteric
Blood drains to hepatic portal and free fatty acids are cleared by the liver

26
Q

How does testosterone affect adiposity?

A

It decreases subcutaneous depots and increases visceral depots, particularly in men

27
Q

How does insulin affect adiposity differently in men v women?

A

Higher whole body insulin sensitivity in women (increases adiposity)

Men are less sensitive to anti-lipolysis effects of insulin

Estrogens and androgens lower body fat and improve insulin sensitivity in both sexes

28
Q

How does metabolic activity differ in different types of WAT?

A

Subcutaneous WAT in lean people —> active metabolic activity

Gluteal-femoral WAT tissue —> least active metabolic activity

Visceral WAT —> most active metabolic activity

29
Q

How does sensitivity to sex hormones vary between the different types of WAT?

A

Subcutaneous WAT in lean people is LEAST sensitive

Gluteal-femoral WAT is ESTROGEN sensitive

Visceral WAT is TESTOSTERONE sensitive

30
Q

How does macrophage activity vary between different types of WAT?

A

Subcutaneous WAT: 10-15%, mostly M2 anti-inflammatory

Gluteal-femoral WAT: 10-15%, mostly M2 anti-inflammatory

Visceral WAT: 40-60%, mostly M1 pro-inflammatory***
This is why visceral fat is the most dangerous

31
Q

What is the difference between hypertrophy and hyperplasia of adipose tissue?

A

Hypertrophy = increase in volume
Can but by up to 1000x
REVERSIBLE

Hyperplasia = increase in the number of adipocytes
Generally occurs during first year of life, late pregnancy, and beginning of puberty
NON-REVERSIbLE
Cells derived from pre-adipocytes

32
Q

Visceral obesity results from deposit in the …

A

Mental, mesenteric, and retroperitoneal fat depots

Visceral obesity is usually a sign that lipids are also being deposited ectopically (muscle, liver, pancreas), which could aggravate DM

33
Q

What are the hormones of the adipose organ called?

A

Adipokines - Leptin and Adiponectin

34
Q

Adipokines that is a metabolic regulator and feedback signal on appetite

A

Leptin

35
Q

Adipokine that is for insulin sensitizing and anti-inflammatory hormone

A

Adiponectin

Promotes the uptake of beneficial lipids

36
Q

Other than Leptin and Adiponectin (the two main adipokines), what other adipokines regulate glucose metabolism?

A

Resistin: associated with T2DM and elevated LDL

Omentin: plays crucial roles in the maintenance of body metabolism and insulin sensitivity, and has anti-inflammatory, anti-atherosclerotic, and CV protective effects

Visfatin: released from visceral fat, binds the insulin receptor and exerts a hypoglycemic effect (promotes insulin function)

37
Q

Visceral or Subcutaneous: Leptin

A

SC>V

Stimulated by increased adiposity, targets hypothalamus to decrease appetite, protects body from too much lipid

38
Q

Visceral or Subcutaneous: Adiponectin

A

SC>V

Stimulated by weight loss, targets muscle, liver, heart, and vessels to increase oxidation of FFAs and has anti-inflammatory effects

Beneficial effects on insulin resistance

39
Q

Visceral or Subcutaneous: Tumor necrosis factor alpha

A

V>SC

Stimulated by engorgment of adiposites, acts on liver, muscles, adipocytes etc to decrease adipocyte mass and opposes insulin signaling

40
Q

Visceral or Subcutaneous: Interleukin-6

A

V>SC

Stimulated by inflammatory cytokines, targets liver, muscle, and adipose tissue to oppose insulin signaling

41
Q

What are the beneficial effects of Adiponectin?

A

Improves insulin sensitivity
Anti-inflammatory
Anti-atherogenic
Targets resting skeletal muscle to increase GLUT4
Has CV protective effects
Stimulates liver to promote glucose uptake and energy storage
***Autocrine signaling in adipose promotes adipogenesis and insulin-directed glucose transport

42
Q

In mouse studies, over expression of Adiponectin in fat tissue leads to …

A

An increase in SC fat, and yet it protects against diet-induced insulin resistance

43
Q

What are the pro-inflammatory adipokines?

A

TNFa

Interleukin-6

Interleukin-1 (regulatory, promotes tumor growth)**
One of the theories as to why obesity is associate with a higher cancer risk

44
Q

What happens when fat gets inflamed?

A

Constraints on extracellular matrix and diffusion limited hypoxia —> necrotic conditions

Macrophages increase 10% to 50% of cells

M1 macrophages increase proinflammatory cytokines (ie TNFa), which inhibit insulin action

Chronic low-grade inflammation —> increased ROS

Associated with elevated risk of cancer and can exasperate T2DM

45
Q

Where does Leptin signaling occur in the brain?

A

In the arcuate nucleus of the hypothalamus

46
Q

Anorexigenic or Orexigenic: Melanocortins

A

Melanocortins (POMC) suppress appetite —> anorexigenic

47
Q

Anorexigenic or Orexigenic: Neuropeptide Y (NPY)

A

Potent appetite stimulus —> orexigenic

Also decreases metabolic rate and suppresses fertility

48
Q

Anorexigenic or Orexigenic: Agouti-related protein (AgRP)

A

Potent appetite stimulant —> orexigenic

Also decreases metabolic rate and suppresses fertility

49
Q

Anorexigenic or Orexigenic: Ghrelin

A

When released from the stomach, it stimulates NYP and inhibits the action of Leptin and POMC —> Orexigenic

50
Q

What are the anorexigenic inputs to the hypothalamus?

A

Leptin (secreted from adipose tissue, weight loss in obese individuals reduces Leptin)

Insulin inhibit NYP cells

Amylin slows gastric emptying and signals satiety

Peptide PTT produced by small and large intestine inhibits NPY neurons

Cholecystokinin (CCK) released from the mucosal lining of the small intestine in response to a meal signals satiety

51
Q

What are the orexigenic inputs to the hypothalamus?

A

Ghrelin, the hunger hormone released by the stomach, peaks before food is eaten and falls immediately after a meal

52
Q

Explain why Leptin resistance is now an alternative theory as to the cause of obesity

A

Normally, Leptin inhibits insulin secretion in a classic negative feedback regulation

Leptin stimulates liver gluconeogenesis by vagal stimulation, and muscle, heart, BAT glucose uptake via ANS-sympathetic NS

When the feed back is lost, hyperinsulinemia increases weight gain, aggravates DM, and elevates Leptin levels

In Leptin resistant over-weight individuals, the permeability of the BBB to Leptin is decreased, leading to increases in appetite

53
Q

Why do Biggest Loser contestants have a much reduced metabolic rate

A

Leptin levels crashed by the end of the season, and only recovered to ~50% of normal after six years (the never get back up to normal metabolic rate levels because of Leptin resistance)

Phys II Unit II (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions