Adipose Tissue

Question 1

What are the primary and secondary locations of adipose tissue in the human body?

Answer 1

Primarily beneath the skin, and secondarily around internal organs.

Question 2

What percentage of body mass does adipose tissue represent in normal-weight men and women, respectively?

Answer 2

In men: 15–30%; in women: 20–25%.

Question 3

How do adipocytes arise developmentally in connective tissue?

Answer 3

They are derived from primitive mesenchymal cells that differentiate into pre-adipocytes, transform into lipoblasts, and eventually mature into adipocytes.

Question 4

What is the developmental sequence leading to a mature adipocyte?

Answer 4

Mesenchymal cell → pre-adipocyte → lipoblast → mature adipocyte.

Question 5

How does the size of a mature adipocyte compare to other cell types?

Answer 5

It is significantly larger than most other cell types in connective tissue

Question 6

In what forms can adipocytes be found within supporting tissue?

Answer 6

In isolation, in clumps within loose connective tissue, or as the dominant cell type in adipose tissue.

Question 7

Trace the developmental origin of adipocytes from their primitive precursors.

Answer 7

Adipocytes are derived from primitive mesenchyme where they develop as lipoblasts.

Question 8

Distinguish the role of lipoblasts in the maturation pathway of adipocytes.

Answer 8

Lipoblasts are the transitional cells in the adipocyte lineage, forming as pre-adipocytes accumulate fat on their way to becoming mature fat cells.

Question 9

How does adipose tissue functionally differ from other loose connective tissues?

Answer 9

It is specialized for efficient fat storage, with adipocytes being the dominant and functionally specialized cell type.

Question 10

What is the embryological origin of adipose tissue?

Answer 10

Adipose tissue originates from undifferentiated mesenchymal cells in the embryonic mesenchyme.

Question 11

What transformation occurs in pre-adipocytes during their maturation?

Answer 11

They accumulate intracellular fat and differentiate into lipoblasts, which eventually become mature adipocytes.

Question 12

Which other connective tissue cell type, aside from adipocytes, originates from undifferentiated mesenchymal cells?

Answer 12

Fibroblasts.

Question 13

Under what physiological condition can mature unilocular fat cells revert to the lipoblast stage?

Answer 13

When a large amount of lipid is mobilized by the body.

Question 14

List the three main sources from which adipocytes derive stored fat.

Answer 14

1. Dietary fat as chylomicrons in bloodstreams; 2. Liver-synthesized triglycerides in circulation; 3. Triglycerides synthesized from glucose within adipocytes.

Question 15

Why does adipose tissue possess a generally rich vascular supply?

Answer 15

To facilitate rapid transport and mobilization of lipids and hormones influencing fat metabolism.

Question 16

The rate of lipid deposition and utilization in adipose tissue is primarily determined by _____ and _____.

Answer 16

Dietary intake and energy expenditure.

Question 17

Which physiological systems and factors profoundly influence adipocyte fat metabolism beyond diet and energy usage?

Answer 17

Hormones and the sympathetic nervous system.

Question 18

State four metabolic and regulatory roles of adipocytes.

Answer 18

1. Energy storage; 2. Endocrine functions; 3. Secretion of proteins modulating metabolism; 4. Regulation of body mass in coordination with hormones like insulin.

Question 19

Through secretion of several proteins, adipocytes modulate _____ and influence _____ in coordination with hormones such as _____.

Answer 19

Energy metabolism; general metabolism; insulin.

Question 20

Identify six adipocytokines (proteins) secreted by adipose tissue.

Answer 20

Leptin, adipsin, resistin, adiponectin, TNF-alpha, and plasminogen activator inhibitor type 1.

Question 21

Compare the anatomical distribution of adipose tissue with that of another connective tissue.

Answer 21

Adipose tissue is distributed throughout the body in the same general locations as areolar connective tissue.

Question 22

List six specific anatomical locations of adipose tissue.

Answer 22

1. Subcutaneous layer deep to skin; 2. Around the heart; 3. Around the kidneys; 4. Yellow marrow of long bones; 5. Padding around joints; 6. Posterior to the eyeball in the eye socket.

Question 23

During tissue processing, lipid is removed from cells by _____ and _____, resulting in an empty vacuole surrounded by _____ that makes adipocytes appear as _____.

Answer 23

Alcohol; xylene; thin ring of cytoplasm; signet ring cells.

Question 24

Explain how the microscopic appearance of unilocular adipocytes is altered by routine histological preparation.

Answer 24

The lipid droplet is dissolved, leaving an empty vacuole surrounded by a thin ring of cytoplasm with eccentric, flattened nuclei.

Question 25

In microscope preparation of uniocular adipocyte, the lipid droplet is dissolved, leaving an empty vacuole surrounded by a thin ring of cytoplasm with _______ nuclei.

Answer 25

eccentric, flattened

Question 26

What potential artifact can occur during histological slide preparation of adipose tissue?

Answer 26

The remaining cytoplasmic rim may rupture and collapse, distorting the tissue architecture.

Question 27

State three major physical or mechanical roles of adipose tissue beyond energy metabolism.

Answer 27

Thermal insulation, filling spaces between tissues and stabilizing organs, and acting as shock absorbers (especially in soles and palms).

Question 28

Adipose tissue, due to its poor conductivity, contributes significantly to _____.

Answer 28

Thermal insulation of the body.

Question 29

Which specific subcutaneous role does adipose tissue perform in body aesthetics?

Answer 29

It shapes the surface of the body.

Question 30

Explain how adipose tissue provides mechanical protection in specific body regions.

Answer 30

It forms protective pads that absorb shock, particularly in high-impact areas like the soles and palms.

Question 31

What are the two major types of adipose tissue and what distinguishes them?

Answer 31

White (unilocular) and brown (multilocular) adipose tissue.

Question 32

White and brown adipose tissues differ in ___, ____, ___ and _____

Answer 32

They differ in structure, location, color, and pathologic characteristics.

Question 33

What percentage of body weight does white adipose tissue represent in well-nourished adults?

Answer 33

In males: up to 20%, in females: up to 25%.

Question 34

Where is white adipose tissue primarily distributed in the body?

Answer 34

It is distributed throughout the body, particularly in the deep layers of the skin.

Question 35

White adipocytes are ____ when isolated but become _____ when closely packed in adipose tissue.

Answer 35

Spherical; Polyhedral.

Question 36

What is the main function of white adipocytes in the body?

Answer 36

Long-term energy storage.

Question 37

What is the typical size range of white adipocytes?

Answer 37

50 to 150 µm in diameter.

Question 38

How much of the weight of a white adipocyte is made up by lipid?

Answer 38

85% of the cell's weight is made up of lipid.

Question 39

What does the term "unilocular" mean in relation to white adipocytes?

Answer 39

Storage of triglycerides in a single large lipid droplet or in a single locus.

Question 40

What factors influence the color of white adipose tissue?

Answer 40

It varies from white to dark yellow depending on diet, particularly the presence of carotenoids.

Question 41

White adipose tissue is absent in the _____, _____, _____, and the entire _____ of the external ear (without the ____).

Answer 41

Eyelids; penis; scrotum; auricle without the lobule.

Question 42

How does the distribution of white adipose tissue differ between males and females?

Answer 42

Distribution is partly regulated by sex hormones and adrenocortical hormones, leading to different patterns in males and females.

Question 43

How does the distribution of white adipose tissue change with age?

Answer 43

In newborns, it has a uniform thickness across the body.

Question 44

What are the three primary functions of white adipose tissue?

Answer 44

1. Energy storage; 2. Thermal insulation; 3. Cushioning against mechanical shock (e.g., around kidneys).

Question 45

Describe the structural characteristics of white adipose tissue at the cellular level.

Answer 45

Fat is stored as lipid droplets that fuse into a large droplet, displacing the nucleus to one side, and reducing the cytoplasm to a small peripheral rim.

Question 46

What is the appearance of the cytoplasm in white adipocytes under microscopy?

Answer 46

Pink-stained cytoplasm.

Question 47

In white adipocytes, the lipid droplet has an _____ outline, with numerous _____ droplets at the periphery in the process of fusion.

Answer 47

Irregular; small.

Question 48

What is the relationship between the lipid droplet and the plasma membrane in white adipocytes?

Answer 48

The lipid is not bounded by a membrane.

Question 49

What organelles are most notably found in the cytoplasmic rim of white adipocytes?

Answer 49

Mitochondria.

Question 50

What surrounds each adipocyte in white adipose tissue?

Answer 50

Each adipocyte is surrounded by an external lamina.

Question 51

In the extracellular tissue adjacent to white adipocytes, a _____ cytoplasmic process and _____ can be seen.

Answer 51

Fibroblast; collagen fibrils.

Question 52

What can be observed in an electron micrograph of two adjacent white adipocytes?

Answer 52

The large lipid droplets have an irregular outline with small lipid droplets at the periphery, and the lipid is not membrane-bound.

Question 53

What is the relative size of the blood capillaries in relation to white adipocytes?

Answer 53

The dimensions of blood capillaries are much smaller compared to the surrounding adipocytes.

Question 54

______ amounts of brown adipose tissue are found in human adults.

Answer 54

Only small.

Question 55

What is the primary role of brown adipose tissue in newborn mammals and some hibernating animals?

Answer 55

Body temperature regulation.

Question 56

Multilocular tissue cells are ____ and _____ than unilocular adipose cells.

Answer 56

Polygonal; Smaller.

Question 57

What is the difference in structure between brown adipocytes and white adipocytes?

Answer 57

Brown adipocytes are smaller, polygonal, and contain multiple lipid droplets, whereas white adipocytes are larger and store fat in a single large droplet.

Question 58

Nucleus in brown adipose cell is ___ and ____.

Answer 58

spherical and central.

Question 59

What components are found in the cytoplasm of brown adipocytes?

Answer 59

A great number of lipid droplets of various sizes, a spherical and central nucleus, and numerous mitochondria with long cristae.

Question 60

Brown adipose tissue receives direct _____ innervation.

Answer 60

Sympathetic.

Question 61

Why does brown adipose tissue appear brown under macroscopic examination?

Answer 61

The mitochondria in brown adipose tissue are rich in cytochromes, which give it a brown color.

Question 62

What is the percentage of brown adipose tissue in human newborns?

Answer 62

2-5% of body weight in human newborns.

Question 63

Where is brown adipose tissue mainly located in humans?

Answer 63

Primarily around the shoulder blades and kidneys.

Question 64

The nuclei in brown adipocytes are _____ and _____ located, with a significant quantity of _______ cytoplasm surrounding them in comparison white nuclei of white adipose tissue.

Answer 64

larger; eccentrically located; strongly eosinophilic cytoplasm surrounding the nuclei.

Question 65

In brown adipocytes, the stored lipid is contained within _____ droplets, unlike the ____ droplet in white adipocytes.

Answer 65

Multiple; single.

Question 66

What happens to the lipid droplets in brown adipocytes during routine histological tissue processing?

Answer 66

The lipid droplets are dissolved, leaving behind a characteristic appearance of the cells.

Question 67

What is the role of mitochondria in brown adipocytes?

Answer 67

Mitochondria in brown adipocytes contain numerous, closely packed cristae and are rich in cytochromes, playing a role in oxidative energy production. The cytochromes are responsible for brown colour of brown adipose tissue.

Question 68

Energy produced by mitochondria in brown adipose tissue is for ATP production. T or F

Answer 68

False.

Question 69

The energy produced by mitochondria in brown adipose tissue is dissipated as _____

Answer 69

Heat.

Question 70

How does brown adipose tissue generate heat in response to cold?

Answer 70

Nerve impulses release epinephrine, which stimulates lipase in adipocytes to release fatty acids, which are metabolized to produce heat.

Question 71

The name of the transmembrane protein present in mitochondria of multilocular adipocytes.

Answer 71

Thermogenin.

Question 72

What is the role of the protein thermogenin in brown adipocytes?

Answer 72

Thermogenin, a transmembrane protein, is involved in the process of heat production in brown adipocytes.

Question 73

Describe the distribution of brown adipose tissue in hibernating animals compared to humans.

Answer 73

In hibernating animals, it is more abundant (as part of a hibernating gland), while in humans it is mainly found in newborns and greatly reduces with age.

Question 74

The mitochondria in brown adipocytes are involved in the _____ energy production chain.

Answer 74

Electron transport.

Question 75

What is the physiological outcome when brown adipose tissue produces heat in response to cold exposure?

Answer 75

Warmed blood circulates throughout the body, helping to maintain body temperature.

Question 76

What anatomical feature distinguishes brown adipose tissue's rich blood supply?

Answer 76

A rich network of capillaries is found between the brown adipocytes.

Question 77

What is the key function of brown adipose tissue in animals and newborns that is not shared by white adipose tissue?

Answer 77

Heat production, crucial for thermoregulation in response to cold environments.

Question 78

Functions of white adipocytes are ____, _____ and ____; brown adipocytes majorly functions for _____

Answer 78

White: energy store, thermal insulator under the skin, shock absorber for e.g kidney. Brown: heat production.

Question 79

Define obesity based on percentage above ideal body weight.

Answer 79

A person is considered obese if their body weight is at least 20% higher than it should be.

Question 80

Obesity is a condition where a person has accumulated so much body fat that it might ______________.

Answer 80

Have a negative effect on their health.

Question 81

A person is considered obese if their body weight is at least ____% higher than it should be.

Answer 81

20.

Question 82

Name the syndrome characterized by abdominal obesity, lipid changes in blood, hypertension, insulin resistance, and a proinflammatory/prothrombotic state.

Answer 82

Metabolic syndrome.

Question 83

What type of benign tumors can unilocular adipocytes form?

Answer 83

Lipomas.

Question 84

What is the name of the rare malignant tumor derived from adipocytes?

Answer 84

Liposarcoma.

Question 85

True or False: Liposarcomas are common in humans.

Answer 85

False. Liposarcomas are infrequent in humans.