Block III: video 5

Question 1

WHat is adipose tissue?

Answer 1

A specialized form of connective tissue in
which have large accumulations of fat cells
(adipocytes)

Question 2

What are the types of adipose tissue and how do they differ?

Answer 2

White fat and brown fat that differentiate from different cell origins under influence of different
transcription factors

Question 3

What is white fat and its functions?

Answer 3

(unilocular)
1. typical type of fat in adults.
2. Acts as a major energy store for the body.
3. Large cells
4. single large drop of fat -signet ring shape

Question 4

What is brown fat and its functions?

Answer 4

(multilocular)
1. present in some areas of fetus & neonate, and isolated areas in adult.
2. Multiple droplets of fat in cytoplasm.
3. Can generate heat, rather than acting as an energy store

Question 5

WHat does brown fat involve?

Answer 5

Involves inner mitochondrial membrane uncoupling
protein UCP-1 (thermogenin) which uncouples oxidation of lipids from ATP synthesis

Question 6

identify

Answer 6

low magnification of white adipose tissue

Question 7

identify

Answer 7

high magnification of white adipose tissue

Question 8

identify

Answer 8

brown fat at low magnification

Question 9

identify

Answer 9

brown fat at high magnification

Question 10

What other things does adipose tissue secrete?

Answer 10

white fat is considered an endocrine organ that secretes adipokines including hormones, growth factors, and cytokines that are important for energy
storage, metabolism, and weight control

Question 11

WHat hormone is important in adipose tissue?

Answer 11

sex hormone metabolism

Question 12

What is the brain-gut-adipose axis?

Answer 12

adipose tissue: regulates appetite, hunger, satiety, and energy homeostasis

Question 13

What is lipoprotein lipase?

Answer 13

for the storage of lipids: is an enzyme, sythesized by adipose cells, that breaks down lipids and is transferred to the luminal surface of the associated capillaries.

Question 14

What type of molecules does lipoprotein lipase breaks down?

Answer 14

very-low-density lipoproteins (VLDLs) into
triglycerides and fatty acids in the capillary endothelium

Question 15

What happens after the low density lipoproteins break into lipids in the capillaries?

Answer 15

The free fatty acids and triglycerides from the capillaries then enter the adipose cells and become re-esterified and stored as triglycerides in the
large fat droplet. Fatty acids may also be synthesized from glucose

Question 16

what molecule promotes fat storage

Answer 16

insulin

Question 17

By what is the release of stored lipids affected?

Answer 17

by neural impulses and/or adrenaline.
Also affected by glucagon & growth hormone (acts in opposite direction of insulin)

Question 18

Explain the process of release of lipids

Answer 18

During release, stored triglycerides are hydrolyzed by hormone-sensitive lipase which is activated by cAMP, and the released free fatty acids enter back into the capillaries

Question 19

What does short term weight regulation on daily basis involves?

Answer 19

• Ghrelin – an appetite stimulant (stomach gastric cells)
• Peptide YY (PYY) an appetite suppressant (small intestinal epithelial cells)

they both act through receptors in the hypothalamus

Question 20

what does long term weight regulation involve?

Answer 20

1. insulin
2. leptin

Question 21

How does insulin work?

Answer 21

increases the accumulation of lipid by increasing synthesis of lipoprotein lipase and increasing the uptake of glucose which can be converted
to lipid. [store fat for future use]

May also suppress or inhibit hormone-sensitive lipase breakdown of fat

Question 22

how does leptin work?

Answer 22

a hormone made in adipocytes as well as other tissues that acts to reduce food intake. Morbidly obese individuals are often resistant to it because
of defective leptin receptors in the hypothalamus or other factors. (supresses appetite)

Question 23

how does both insulin and leptin work?

Answer 23

For regulation of weight both can act through receptors in the hypothalamus.

Although insulin’s main action may be at the level of cellular glucose uptake there is evidence that it may be regulated in part through receptors in the
hypothalmus

Question 24

Explain obesity

Answer 24

Obesity has been recently classified as a disease by the Centers for Disease Control and the World Health Organization. Individuals are considered to be
obese if their adipose tissue buildup results in a body mass index (BMI) greater than 30 kg/m2 where m is the height in meters.

Research suggests that obesity is almost always accompanied by chronic inflammation in the adipose tissue, and can be associated with a number of
health related problems.

Question 25

What are the types of obesity?

Answer 25

Hypertrophic obesity
Hypercellular obesity (hyperplastic or hyperplasia)

Question 26

Explain hypercellular obesity

Answer 26

Increase in number of adipocytes
It is a frequent cause of childhood obesity involving both genetic factors and environmental factors

Question 27

Explain hypertrophic obesity

Answer 27

Increase in amount of fat stored in each cell (adult onset)

Question 28

How does obesity impact molecules?

Answer 28

obesity can involve major changes in hormones such as leptin and insulin, and resistance to the effects of these hormones, as well as increased inflammation due to factors such as IL-6.

It has a high correlation with the development of type II diabetes and cardiovascular disease in overweight
individuals

Question 29

does adipose tissue have stem cells?

Answer 29

Recent studies have shown that white adipose tissue has a 100-fold richer supply of stem cells than does bone marrow

Question 30

What are the stem cell from adipose tissue called and what do they do?

Answer 30

adipose-derived stem cells have the capacity
to be transformed into cartilage cells (chondrocytes), muscle cells (myoblasts), bone cells (osteoblasts) as well as adipocytes