Chapter 6 - Adipose Tissue

Chapter 6

Adipose Tissue

D. Caveolae

In white adipose tissue, which among the following are important for lipid trafficking and formation of large triglyceride storage droplet? A. SER B.RER C. Fibroblast D.Caveolae

Group

6

White adipose tissue and Brown adipose tissue

Identify: Two (2) major types of adipose tissue

C. Brown Adipose Tissue

The following slide is predominantly: A. Artifacts B. SER C. Brown Adipose Tissue D. White Adipose Tissue

C. Norepinephrine. Brown Adipose Tissue have a sympathetic nerve ending of norepinephrine that stimulates mitochondrial production of heat

Brown Adipose Tissue have a sympathetic nerve ending of which catecholamine/s that stimulates mitochondrial production of heat? a. Dopamine b. Epinephrine c. Norepinephrine d. AOTA

B. Mesoderm

Brown and White adipocytes are obtained from what germ layer? A. Ectoderm B. Mesoderm C. Endoderm D. Exoderm

A. smaller lipid droplets allow the nucleus to be more centrally located

Cells of brown fat are polygonal and generally smaller than white adipocytes. The smaller lipid droplets allow the nucleus to be more peripherally located. a. First statement is correct b. Second statement is correct c. Both statements are correct d. Both statements are incorrect

Lipoprotein Lipase

Chylomicrons and VLDL's will be hydrolyzed at the luminal surfaces of capillaries by this enzyme synthesized by adipocytes. It's production is also stimulated by Insulin

False, Chylomicrons are formed only in the endoplasmic reticulum of enterocytes (absorptive cells) of the small intestine

Chylomicrons are formed from ingested lipids in epithelial cells lining the large intestine and circulated through the body via blood and lymph

Hormone Sensitive Lipase (HSL) Rationale: PKA phosphorylation of HSL results in two-to threefold activation of the enzyme lipolytic activity, which promotes translocation of HSL to the lipid droplet.

Fill in the blank: Norepinephrine released in the adrenal gland and by post-ganglionic sympathetic nerves in adipose tissue activates a _______ lipase that breaks down triglycerides at the surface of the stored lipid droplets.

Triglyceride, Fatty Acids, Cholesterol

Fill in the blanks: Chylomicrons are large ____ rich lipoproteins produced in enterocytes from dietary lipids such as Fatty ____ and ______

Circulating lipoproteins Rationale: These lipoproteins are measured in clinical tests after fasting to allow depletion of chylomicrons.

Fill in the blanks: Levels of _______ are routinely measured in clinical tests for blood lipids after fasting.

Cyclic AMP (cAMP) signaling mechanism Rationale: cAMP in turn activates protein kinase A (PKA), thereby stimulating fat hydrolysis via activation of hormone-sensitive lipase. Fat hydrolysis ultimately leads to the liberation of glycerol and free fatty acids.

Fill in the blanks: Norepinephrine from nerve endings stimulates the __________________ system, which activates hormone-sensitive lipase to hydrolyze the stored triglycerides to free fatty acids and glycerol.

Free Fatty Acids (FFA)

Fill in the blanks: The __________ acids diffuse across the membranes of the adipocyte and the capillary endothelium, and bind the protein albumin in blood for transport throughout the body.

B. Mitochondria - Mitochondria contains cytochrome pigment that gives the color of the brown fat.

Fill in the blanks: The color of Brown Fat is due to the very abundant ________ scattered among the lipid droplets of the fat cells. a. Nucleus b. Mitochondria c. Ribosomes d. Cytoplasm

whitish-yellow fat; darker Rationale: White adipose tissue are very large, containing a single huge droplet of lipid filling almost the entire cell. Brown adipose tissue's color of brown fat is due to the abundant mitochondria scattered among the lipid droplets.

Fill in the blanks: White adipose tissue consist of cells each containing one large cytoplasmic droplet of _____-_______ ____ while brown adipose tissue contains cells with multiple lipid droplets interspersed among abundant mitochondria, giving the tissue a ________ appearance.

C. Both A and B

Free Fatty Acids enter adipocytes via A. Active Transport B. Diffusion C. Both A & B D. Another form of transport / None of the above

D. All of the Above HSL is characterized by its epinpehrine sensitive lipolytic activity in adipose tissue, as such its name reflects by which it is stimulated

Hormone Sensitive Lipase can be stimulated by: A. Growth Hormone (GH) B. Glucagon C. ACTH D. All of the Above

Beige Adipocytes

Identify: A cell which is logical and metabolic features generally intermediate between white and brown adipocytes.

Adipose tissue Rationale: Connective tissue in which fat-storing cells or adipocytes predominate is called ADIPOSE TISSUE.

Identify: It is a connective tissue in which fat-storing cells predominate

Preadipocytes

Identify: It is derived from mesenchymal cells which differentiates into white and brown adipose tissue. It is characterized as a fibroblasts like cell but larger with cytoplasmic lipid droplets

UCP1/Uncoupling protein 1/Thermogenin

Identify: The transmembrane protein in the inner mitochondrial membrane which is responsible for greater heat production in brown adipocytes.

White adipose tissue Rationale: White adipose tissue is specialized for long-term energy storage and plays a critical role in whole body energy homeostasis.

Identify: What is the most common type of adipose tissue that specializes for fat storage?

C. Thermal insulation Rationale: Epithelial tissue provide protection and secretion, Connective tissue provide transportation and Adipose tissue provide thermal insulation for the body.

Multiple Choice: Adipose tissue conducts heat poorly and provides __________ for the body A. Protection B. Transportation C. Thermal insulation D. Secretion

B. neurologic disorder Rationale: With growing epidemic of obesity and its associated health problems, including diabetes and heart disease, adipocytes and adipose tissue now constitute a major area of medical research.

Multiple Choice: The following are reasons why adipocytes and adipose tissue now constitute a major area of Medical Research, except. A. growing epidemic of obesity B. neurologic disorder C. diabetes D. heart diseases

C. 9.3 kcal/g Rationale: The caloric density of triglycerides is 9.3 kcal/ g, is twice that of protein or carbohydrates (4 kcal/ g)

Multiple Choice: What is the caloric density of triacylglycerol? A. 7 kcal/g B. 4 kcal/g C. 9.3 kcal/g D. 9.5 kcal/g

B. Contractility Rationale: Muscle tissue optimize the universal cell property of Contractility.

Multiple Choice: Which of the following is NOT a function of Adipose tissue? A. Cushioning B. Contractility C. Thermal insulation D. Hormone release

Post-ganglionic, hormone sensitive

Norepinephrine is released by ___ sympathetic nerves and activates a ____ lipase to break down triglycerides.

False Rationale: brown adipocytes has UCP1/Uncoupling protein 1/Thermogenin, which is a transmembrane protein in the inner mitochondrial membrane responsible for its greater heat production

T/F. Heat production in brown adipocytes is less than that of other cells.

True Rationale: Also shown is a sympathetic nerve ending that releases norepinephrine to stimulate mitochondrial production of heat

T/F. The diagram shows a single multilocular adipocyte with a central nucleus, numerous small lipid droplets and many mitochondria.

True Rationale: Instead of producing ATP, the energy associated with this proton flow dissipates as heat.

T/F. UCP1 permit the flow of protons from the intermembranous space to the matrix without passing through ATP synthetase complexes.

True Rationale: Adipose tissue release hormones and is now recognized as an endocrine organ at the center of nutritional homeostasis.

T/F: Adipocytes are active cells metabolically, responding to both nervous and hormonal stimuli

False Rationale: Adipose tissue normally represents 15%-20% of the body weight in men, somewhat more in women.

T/F: Adipose tissue normally represents 15%-20% of the body weight in women, somewhat more in men.

False Rationale: White adipose tissue and brown adipose tissue both have a rich blood supply BUT the adipocytes are individually surrounded by a THIN external lamina containing Type IV collagen.

T/F: Both types of adipose tissues have a rich blood supply and the adipocytes are individually surrounded by a thick external lamina containing Type II collagen

True Rationale: The small lipid droplets, abundant mitochondria and rich vasculature of brown adipose tissue all help mediate the tissue's principal function of heat production and warming of blood.

T/F: Brown adipocytes release heat and function to warm the blood

True Rationale: Brown adipose tissue also develops from mesenchyme, but involves preadipocytes in a different embryonic location (paraxial) from those producing white adipose tissue.

T/F: Brown adipose tissues are developed from the paraxial region of the mesenchyme.

False Rationale: White, Brown and beige adipocytes are developed from the differentiation of preadipocytes

T/F: Brown and beige adipocytes are developed from the differentiation of white adipocytes.

True Rationale: Albumin acts as main fatty acid binding protein in extracellular fluids. Plasma albumin possesses numerous binding sites for fatty acids with moderate to high affinity, enhancing the concentration of fatty acids.

T/F: Free fatty acids and glycerols diffuse into the capillary, where the fatty acids bind albumin for transport throughout the body for use as an energy source.

False Rationale: In adults, the amount and activity of brown fat are higher in lean individuals.

T/F: In adults, the amount and activity of brown fat are lower in lean individuals.

True

T/F: In humans the amount of brown fat is maximal relative to body weight at birth, when thermogenesis is most needed and partially disappears by involution and apoptosis during childhood.

True Rationale: studies of the tissue in animals ending their hibernation period, and in newborn humans, nerve impulses liberate norepinephrine into brown adipose tissue. Unlike the process in white fat, liberated fatty acids of brown/multilocular adipocytes are not released but are quickly metabolized, with a consequent increase in O2 consumption and heat production that raises the temperature within the tissue and warms the locally circulating blood, which then distributes the heat throughout the body.

T/F: The main function of brown adipocytes or multilocular adipose cells is to produce heat by non-shivering thermogenesis.

True Rationale: This is due to the thermogenic activity and stimulation of the autonomic nerves.

T/F: The number of brown adipocytes increases during cold adaptation, usually appearing as clusters of multilocular cells in white adipose tissue.

True Rationale: Excessive formation of adipose tissue or obesity occurs when energy intake exceeds energy expenditure.

T/F: When energy intake exceeds energy expenditure it can result to an excessive formation of adipose tissue

True Rationale: White adipocytes are unilocular, with one large lipid droplet occupying most of the cytoplasm. The white adipocyte is usually much larger in relation to the other cell types and Brown adipocytes remain multilocular (having many small lipid droplets) with numerous mitochondria.

T/F: White adipocytes are unilocular with one large lipid droplet and brown adipocytes are multilocular with many small lipid droplets.

False Brown adipocytes emerge earlier than white fat during fetal development.

T/F: White adipocytes emerge earlier than brown fat during fetal development.

True Rationale: Increased amounts of white adipose tissue seen in obesity which is characterized by a state of chronic mild inflammation. Proinflammatory factors released from visceral fat are being investigated for links to the inflammation-related disorders associated with obesity, such as diabetes and heart disease.

T/F: White adipose tissue secretes numerous proinflammatory cytokines

True Rationale: This is to form triglycerides again which are then deposited in the growing lipid droplet.

T/F: Within the adipocytes, the fatty acids combine with glycerol phosphate and is supplied by glucose metabolism.

D. White Adipose Tissue

The following slide is predominantly: A. Artifacts B. SER C. Brown Adipose Tissue D. White Adipose Tissue

A. Energy Storage

The main function of the following slide is : A. Energy Storage B. Heat Production C. Detoxification D. Phagocytosis

B. Heat Production Rationale - Brown adipose tissue constitutes 2%-5% of the new born body weight, located mainly in the back, neck and shoulders and its principal function is for heat production and warming the blood

The main function of the shaded area on the newborn is: A. Energy Storage B. Heat Production C. Detoxification D. Phagocytosis

B. Mitochondria Rationale : Brown fat has very abundant mitochondria which contains cytochrome pigment scattered among the lipid droplets.

The pigment of this slide is due to high number of which of the following: A. Blood Vessels B. Mitochondria C. Hemoglobin D. SER

Insulin

This hormone accelerates adipocyte conversion into triglycerides by stimulating glucose uptake, it also inhibits HSL and reduces FA release

True

True or False. Brown Adipose Tissue specialized for heat production.

False. Brown adipocytes are multilocular and contain many small lipid inclusions.

True or False. Brown adipocytes contain many small lipid inclusions and therefore called unilocular

False Rationale: It is controlled by sex hormones not by GH

True or False: Distribution of white adipose tissue in the breast and thighs are controlled by Growth Hormones.

D. All of these

True regarding histogenesis of white adipose tissue A. Derived from mesenchymal stem cells B. Begins to accumulate at 14th week of gestation C. Excessive adipose tissue accumulation due to sedentary lifestyle D. All of these

C. Sex Hormones Rationale: Sex hormones partly regulates the deposition of white adipose tissue in breast and thigh.

What hormone /hormones regulates the deposition of this image in breast and thighs? A. GH B. Insulin C. Sex Hormones D. All of the Above

Leptin Rationale: Leptin is a polypeptide hormone with target cells in the hypothalamus which is released from white adipocytes and helps regulate eating behavior.

What is a polypeptide hormone, also called a "satiety factor" that target cells in the hypothalamus, other brain regions, and peripheral organs which helps regulate the appetite under normal conditions and participates in regulating the formation of new adipose tissue?

B. High levels of Mitochondria Rationale : Brown fat has very abundant mitochondria which contains cytochrome pigment scattered among the lipid droplets. The following image shown is white adipose tissue

Which among the choices is false regarding the image shown? A. Unilocular B. High levels of Mitochondria C. Regulated by sex hormones D. Signet Ring Appearance

C. Both A and B are correct

Which is of the following defines beige adipocytes? A. With adaptation to cold temperatures beige adipocytes change reversibly, forming many more small lipid droplets B. Identified to have histological and metabolic features generally intermediate between white and brown adipocytes. C. Both A and B are correct D. None of the above

D. Nucleus peripherally located Rationale : In brown adipose tissue nucleus are more centrally located

Which of the following statement is false regarding the slide given? A. Abundant mitochondria B. Warms Blood C. Many blood capillaries D. Nucleus peripherally located

C. Nucleus centrally located Rationale: White adipose nucleus has a signet ring appearance with lipid droplet displacing and flattening the nucleus AGAINST THE CELL MEMBRANE.

Which of the following statement is false regarding white adipose tissue? A. Unilocular B. Signet-Ring Appearance C.Nucleus centrally located D. Storage of Energy

D. Controlled by Sex Hormones Rationale: the following slide shown is Brown adipose tissue that is controlled by sympathetic nerve ending that releases NE to stimulate mitochondrial production.

Which of the statement is false regarding the slide shown: A. Warms blood B. Abundant blood capillaries C. Central spherical nucleus D. Controlled by Sex Hormones

A. Adult onset obesity mainly involves increase in size of existing adipocytes (hypertrophy) and childhood obesity involves increases in both adipocyte size and numbers (hyperplasia)

Which statement is true? A. Adult onset obesity mainly involves increase in size of existing adipocytes (hypertrophy) and childhood obesity involves increases in both adipocyte size and numbers (hyperplasia) B. Adult onset obesity involves increases in both size (hypertrophy) and number (hyperplasia) of existing adipocytes and childhood obesity involves increase in number only C. Both Adult onset and Childhood onset obesity involves increase in both size and number of adipocytes D. None of the statement is true

B. Triglycerides

White adipose tissue is a large droplet of ____________ . A. Cholesterol B. Triglycerides C. Phospholipids D. All of the above