Growth - Adipose Tissue

(encvironmental temperature) feed to body gain ratios will ______ as the extra energy consumed is used for heat production

drop

(anatomical location) adipose tissues that develop _______ usually accumulate more fat compared to those that develop ________

early; late

Adipose tissue is very efficient at storing tissue in the body as well as mobilizing that _______ when it is needed

energy

functions of adipose tissue

energy substrate storage protection and insulation physical support maintenance of serum lipids generation of heat source of hormones

(sex) Increased fatness in females is due to earlier closure of _____ resulting in decreased growth and enhancing fat

epiphyseal plate

what does adipose tissue store

essential fatty acids, fat soluble vitamins A D E K

adipocytes accumulate fatty acids to produce TAGS in lipogenesis by:

extracting FA's from TAGS in blood De novo (From new) synthesis of FA's

fatty acids converted to heat in brown adipose tissue due to ___________, which allows uncoupling of oxidation from ATP formation

fatty acids uncoupling protein I (UCPI)

(sex) increased fatness in _______

females

(lipogenesis) Substrate for de novo synthesis of fatty acids in adipocytes (Ruminant)

glucose

(nutrition) the composition of the diet impacts lipid metabolism:

high fat diets depress FA synthesis low fat diets high in carbohydrates increase FA synthesis and increase TAG storage

lipolysis is controlled by _________ lipases

hormone synthesis

(fetal) adipoblast ____ is significant

hyperplasia

(postnatal) limited adipoblast ________ continues after birth

hyperplasia

(fetal) accumulation of small adipocytes with little ______

hypertrophy

leptin is ________ in obese animals and increases with overfeeding

increased

hormones that have significant effects on adipose tissue composition and metabolism:

insulin (lipogeneic) growth hormone (lipolytic) glucagon (lipolytic) insulin-like growth fator (IGF) (lipogenic/lipolytic) glucocorticoids (lipolytic) catecholamines (lipolytic) (adrenaline) throid hormones (lipolytic) leptin (adipocytes)

fat between muscles (myotome)

intermuscular fat

fat within muscle (marbling) specifically with perimysium

intramuscular

(anatomical location) __________ develops after most other fat tissues

intramuscular fat

lean pigs have only ________ mature adipocytes

larger

(postnatal) new fat cells may be generated in older animals after existing adipocytes become full of ______

lipid

synthesis or absorption of FA from blood, and subsequent esterification to form triglycerides (TAG) in adipocyte

lipogenesis

Fat storage is a function of

lipogenesis lopolysis

net lipid accretion rate

lipogenesis rate - lipolysis rate

(nutrition) reduced energy intake induces ________ so that FA's are released for oxidation

lipoloysis

Physical activity promotes _______ to meet increased energy requirements

lipolysis

release of fatty acids (FA) from adipocyte, which involves breakdown of triglycerides (TAG) within adipocytes and results in diffusion of FA across cell membranes

lipolysis

(lipogensis) endothelial cell walls of capillaries contain the enzyme ________ that hydrolyses TAGs in chylomicrons to glycerol and free fatty acids for uptake by adipocytes

lipoprotein lipas

where does lipogenesis occur in avian species

liver

adipocytes collect together to form ______ that eventually develop into larger ________

lobules; lobes

leptin is ___ in lean animals

lower

leptin circulates concentration related to adipose tissue _______

mass

adipogenesis 1. adipose tissue develops from loose connective tissue derived from the ________

mesoderm

(environmental temperature) animals will eat ______ to keep up with this ________ energy demand

more; increased

(age) large adipocytes high % lipid low % protein and water

old animals

fat surround GI tract

omental

fat surrounding kidneys, pelvis, and heart

perinephric

adipogenesis 3. eventually adipoblasts stop replicating and differentiate into _______

preadipocytes

fat cell that contains some lipogenic enzymes and a few lipid droplets

preadipocytes

(lipogenesis) Dietary FAs used to assemble TAGs in adipocytes (Ruminants)

rumen microbes modify FA before absorption. therefore FA in feed and adipose is different

biohydrenation in lipogenesis takes place in _______

ruminants

carries blood vessels and nerves to adipose tissue

septa

lobules of fat are separated and supported by loose connective tissue called

septa

(sex) Fatness in females associated with increased _______ of adipocytes but fewer in _______ per unit of tissue than males and castrates

size; number

fatter animals have very large adipocytes as well as ______ newly recruited adipocytes

small

external fat under hide (dermatome)

subcutaneous fat

When temperatures drop below the ____________ zone, adipose tissue will be mobilized to produce heat

thermoneutral

(species) ruminant vs monogastric have different fatty acids available for ___________

triglyceride synthesis

(lipogenesis) Dietary FAs used to assemble TAGs in adipocytes (Monogastric)

unmodified FAs absorbed from the diet enters blood stream. Therefore FA in feed and adipose is similar

(fetal) initiation of __________ of connective tissue associated with adipose

vascularization

types of fat

visceral subcutaneous intermuscular intramuscular

(postnatal) postnatal adipose growth is through increasing diameter and _____ of adipocytes

volume

when is energy used

when nutrient intake is restricted energy density in adipose > carbohydrates and proteins

predominant fat in the body long term energy storage few cytoplasmic inclusions poorly developed mitochondria after lipolysis, fatty acids are released from the cell

white adipose

(age) small adipocytes low % lipid high % protein and water

young animals

(nutrition) during high energy intake excess energy is stored as _________ in adipocytes through _______

TAGs; lipogenesis

(lipogensis) Substrate for de novo synthesis of fatty acids in adipocytes (Monogastric)

acetate

(postnatal) new adipocytes differentiate from ______ that are found in loose connective tissue from which fat originally develops

adipoblasts

adipogenesis 2. mesenchymal cells from the mesoderm give rise to _______ which are an early form of a fat cell

adipoblasts

fat cell that contains no lipogenic enzymes or lipid droplets cant create fat

adipoblasts

(species) species with different environmental needs have evolved _______ of different size, number, composition

adipocytes

adipogenesis 4. preadipocytes mature into __________ after lipid droplets coalesce to form one large globule

adipocytes

fat cell that has depostion of lipid that results in hypertrophy or enlargement of each

adipocytes

where does lipogenesis occur in cattle, sheep and pigs

adipose tissue

Factors affecting adipose tissue composition and metabolism

age anatomical location species breed sex hormones nutrition environmental temperature physical activity

(nutrition) _________/protein deficiencies or imbalances will result in increased lipogenesis because lean tissue accretion cannot be maximized

amino acids

leptin reduces

appetite and feed intake

extracting FAs from TAGS in blood during lipogenesis comes from

diet hepatic synthesis (liver makes it)

anatomical location affecting adipose tissue composition

different fat deposits throughout the body accumulate lipid and different rates

(breed) includes differences in the ____________ of fat between adipose tissue

distribution

(sex) sex also influences fat _______

distribution

(anatomical location) intramuscular adipocytes in pigs account for almost _______ of all adipocytes but store only ______ of total lipids body

50%; 10%

insufficient amino acid will limit the use of other amino acids will promote fat deposits

barrel theory

(postnatal) appears to be repeated phases of recruitment resulting in a __________ distribution of fat cells with increased fatness

bimodal

mammals use energy to maintain a constant _____

body temperature

extensive vascularity high numbers of iron containing mitochondria common in neonates, hibernating animals, cold adapted animals used to generate heat smaller cell with multiple fat droplets non shivering thermogensis

brown adipose

what generates heat

brown adipose tissue

lipolysis is primarily stimulated by hormones with ________ actions

catabolic

FAs are targeted to various process including:

catabolized for energy used for membrane synthesis

(lipogenesis) TAGs that reach the blood from the diet are transported from the small intestine attached to lipoproteins. these structures are called

chylamicrons