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What is growth?
general and normal-sized expansion as produced by the accretion of tissue like the original tissue or organ.
What is an example of a myostatin gene mutation?
Double muscled cattle (muscle mass doesn’t shut down until a while after maturity)
What are the three types of growth?
hyperplasia, hypertrophy, accretion
What is hyperplasia?
increase in tissue associated with cell proliferation (increase in cell numbers)
What is hypertrophy?
Increase in the size of cells
What is accretion?
Enlargement of cell size associated with gradual build up of intracellular components.
What types of growth happen in connective tissue?
hypertrophy and accretion
Where does age-related adaptation occur?
adipose tissue and bone
What are the factors that determine growth potential?
genetics, selective breeding, nutrition, environment, domestication
G+E=P, what does that mean?
genetics + environment = phenotype, impacted by both evolution and humans
What happens in utero for growth and development?
Complex and highly regulation progression of event that includes a lot of cellular replication. Different cell lineage will develop into different tissues.
What are the three types of cells?
totipotent, pluripotent, multipotent
What is totipotent?
single cell that have the ability to produce ALL the different cells of the body.
What is pluripotent?
cells hat have the potential to differentiate into different germ layers (MANY things)
What is multipotent?
The cell can potentially develop into multiple cell types at fertilization. (SOME things)
What makes up the endoderm?
GIT and Respiratory System
What makes up the mesoderm?
Muscle, bone, blood vascular, urogenital
What makes up the ectoderm?
Nervous system, sensory, and epidermis
What are the three phases of prenatal development?
ovum, embryonic, fetal
What happens in the ovum stage?
The egg is released and merges with the sperm, creating a zygote
What happens in the embryonic stage?
The end of cell division.
What happens in the fetal stage?
Implantation of the zygote into the uterus.
What are the two major phases of the cell cycle and what happens there?
Interphase (cellular growth and duplication of DNA) and M phase (separation of DNA into two sets of daughter cells)
What are the five phases of the M Phase?
prophase, metaphase, anaphase, telophase, cytokinesis
What are the four phases of embryonic development?
cleavage, blastulation, gastrulation, organogenesis
What happens in the cleavage stage?
series of cell division cycles of the zygote to form the morula.
What happens in the blastulation stage?
development of the morula into a blastula
What happens in the gastrulation stage?
development of the blastula to a gastrula
What happens in the organogenesis stage?
formation of organs and tissues
What are the three types of muscle?
cardiac, skeletal, smooth
True or False, cardiac and smooth muscle terminate at maturity?
True, skeletal does not
What hormones regulate muscle mass?
GH, IGF-1, Steroids, T3 and T4
What pathway has a negative impact on muscle growth?
HPA Axis, catacolamines
What tissues does GH directly and indirectly impact?
liver, bone, skeletal muscle
What are the major direct impacts of GH?
reduced glucose transport and metabolism, lipolysis, and transport of AA
What is an indirect impact of GH and why?
increase muscle mass, primary signal for IGF-1
What is the disorder of excessive GH production AFTER puberty?
Agromely
What is IGF-1’s function?
primary endocrine factor regulation changes in muscle mass
What mediates the release of IGF-1?
GH
What are the two IGF-1 pathways and their impact?
IGF-1 P3-K positive impact, IGF-1 M/S3 negative impact
What does IGF-1 P3-K do?
increase protein synthesis and decrease proteolysis
What does IGF-1 M/S3 do?
decrease protein synthesis and increase proteolysis
What does testosterone do?
binds to specific intracellular androgen receptors in muscle to increase protein synthesis. Also decreases proteolysis.
What does testosterone work in mediation with?
GH
What does Estrogen impact?
skeletal muscle, bone, and adipose with an increase in both protein synthesis and proteolysis.
How does estradiol 17 impact bone?
closure of the epiphyseal plate (growth plate)
Explain the metabolic function of insulin.
Increases muscle cell’s ability to uptake amino acids, lipids, and glucose…. glucose increases the glycogen in muscles.
What synthesis does insulin promote?
protein and glycogen
What is the growth function of insulin?
direct interaction with IGF-1 to promote protein synthesis.
What does thyroid hormones do prenatal?
differentiation of muscle progenitor cells
What does thyroid hormones doe postnatal?
maintenance and repair of cells
What is the definition of protein turnover?
the balance between protein synthesis and degradation of tissue proteins.
What is hypertrophy in terms of protein turnover?
positive protein turnover with increased synethsis
What is atrophy in terms of protein turnover?
negative protein turnover with increased degradation
What are the factors of protein turnover?
genetic, endocrine, immune, nutrition, physiological, environment.
What hormones are anabolic?
GH, IGF-1, Insulin, Testosterone, Estrogen
What hormones are catabolic?
glucagon, glucocorticoids, catecholamines
True or False, T3 and T4 do NOT have a role in synthesis or degradation.
True
What is the most significant impact of GH?
stimulation of IGF-1
What is the most significant impact of IGF-1?
promoting protein synthesis
What is the most significant impact of insulin?
inhibiting protein degradation and enhancing energy directed to protein synthesis
What is the most significant impact of testosterone?
promoting protein synthesis
What is the most significant impact of glucagon?
stimulating protein degradation and blocking the effect of inulin binding receptor
What is the most significant impact of cortisol?
protein breakdown
What is the most significant impact of catecholamines?
protein breakdown
What are the 2 pathways for protein synthesis?
Insulin/IGF-1-Akt-mTOR and Myostatin/Activin-A Pathway
What are the three pathways of protein degradation?
UPP, Calpain/Calpastatin Proteolysis, Apoptosis
What are the three proteolytic enzymes and what do they do?
E1 (activates), E2 (conjugates), E3 (ligase)
What is cofactor ubiquitin?
Attaches to target protein breakdown
What are the three primary parts of 26S proteasome?
19S, 19S, 20S proteosome
What is the calpain system?
intracellular Ca2+ dependent protease enzyme that identifies and targets proteins for processing.
What are the four parts of the calpain system?
µ, m, skeletal muscle, and calpastatin
What does calpastatin do?
inhibits calpain functions
What are the two proteases involved with apoptosis?
caspases and cathepsins
How is bone organized?
isolated cells in a matrix of collagen fibers impregnated with a vast amount of calcium salts
What are the two primary calcium salts in bone?
calcium phosphate and hydroxyapatite
What is hydroxyapatite?
A crystal-like molecule with Ca2+ ions produced by osteoblasts.
What are the different cells of bone?
osteoblasts, osteoclasts, ostecytes
What are osteoblasts?
single nucleated cell
What are osteoclasts?
multi nucleated cell
What are osteocytes?
most common cell type that regulates bone mass
What is longitudinal bone growth?
bone growth that extends the length of bone
Where does LBG occur?
epiphyseal plates
What is the epiphyseal plate?
hyaline cartilage, mostly collagen
What are the three layers of bone growth?
resting, proliferation, hypertrophic
What happens in the resting zone?
stem like cells serve as the primary pool for growth
What happens in the proliferation zone?
resting zone that have differentiated into proliferation
What happens in the hypertrophic zone?
chondrocytes that calcify the proteoglycan of the growth plate
What are the positively regulated hormones of bone growth?
GH-IGF-1 Axis, estrogen (seals off plate), T3/T4, Leptin
What are the negatively regulated hormones of bone growth?
glucocorticoids, catecholamines
What are the properties for GH-IGF-1 Axis?
very potent stimulator of bone growth and is directly driven by the release of GH.
What does GH do in the resting and hypertrophic zone?
proliferation/differentiation in the resting zone and alignment in the hypertrophic zone.
What does IGF-1 do in the proliferation and hypertrophic zone?
maturation in the proliferation zone and hypertrophy in the hypertrophic zone
What is stimulated by GH-IGF-1 in the hypertrophic zone?
collagen, proteoglycans, alkaline phosphatase
What happens when the death of chondrocytes and alkaline phosphate happens?
Longitudinal bars become calcified
What are the primary roles of estrogen in bone growth?
bone mineralization, production of VEGF, growth plate maturation, proliferation of osteoblasts, enhance GH-IGF-1 Axis
What is the role of estrogen pre pubescent?
simulate and regulate bone growth
What is the role of estrogen pubescent?
stimulate maturation and closing of growth plate
What is the role of estrogen post pubescent?
regulate bone turnover
What roles of adipose tissue have been found since 1993?
endocrine, immune, metabolic, reproduction
Old include: protection, thermal regulation, energy