Animal Growth

Question 1

Why study animal growth?

Answer 1

Disease prevention/therapy 
Tissue regeneration
Prevent wasting conditions
Optimize health and well-being
Optimize performance
Growth rate and efficiency important in ag.

Question 2

Growth

Answer 2

increase in size or mass of structural tissues or organs- does not include excess adipose tissue (fat) deposition

Question 3

Hyperplasia

Answer 3

increase in cell number

Question 4

Hypertrophy

Answer 4

increase in cell size due to accretion of cell products

Question 5

Differentiation

Answer 5

the process of acquiring characteristics distinct from a progenitor cell or tissue, such as occurs in progressive diversification of cells and tissues of the embryo

Question 6

What types of animals have growth plates that don’t stop growing?

Answer 6

Castrated animals

Question 7

What happens during the ovum stage?

Answer 7

Fertilized by sperm
Hyperplasia occurs
As cells differentiate morphogenisis occurs
(cells are not increasing in size at this stage therefore it is not hypertrophic growth.

Question 8

What happens during the Embryonic stage?

Answer 8

High rate of cell division, hyperplasia and simultaneous differentiation
While there begins to be some hypertrophy it is still a minor proportion of the growth

Question 9

What is totipotent?

Answer 9

Totipotent stem cells are one of the most important stem cells types because they have the potential to develop into any cell found in the human body.

Question 10

What is pluripotent?

Answer 10

Can’t become everything, but can become a number.

Question 11

Endoderm refers to

Answer 11

internal organs

Question 12

Mesoderm refers to

Answer 12

skeletal muscle

Question 13

Ectoderm refers to

Answer 13

brain, nerves, skin, and hair

Question 14

What are the three germ layers?

Answer 14

Endoderm, Mesoderm, and Ectoderm

Question 15

What occurs during the Fetal stage?

Answer 15

Both hyperplasia and hypertrophy
Dramatic increases in both cell number and size
Represents 80-85% of prenatal time period

Question 16

What occurs during the post-natal stage?

Answer 16

Most muscle growth (nearly all) is hypertrophic growth

Some tissues such as adipose show propensity for both hyperplasia and hypertrophy.

Question 17

What does neonatal mean?

Answer 17

newborn

Question 18

How many more muscle fibers grow after you’re born?

Answer 18

None

Question 19

There is a change in what as we develop?

Answer 19

Proportion

Question 20

Allometry

Answer 20

relationship of growth of a part of an organism to growth of the whole organism

Question 21

During allometry, what happens?

Answer 21

growth at different rates

Question 22

Apoptosis

Answer 22

programmed cell death

Question 23

Atrophy

Answer 23

decrease in size of a cell, tissue, organ, or part

Question 24

Development

Answer 24

change in form and/or function of the animal or tissue, which results from changes in the rate of increase or decrease of individual components of the body or tissue.

Question 25

When does Atrophy happen?

Answer 25

If you don't actively use the muscles.

Question 26

What is the opposite of Atrophy?

Answer 26

Hypertrophy

Question 27

An increase in strenuous exercise would happen during what?

Answer 27

Hypertrophy

Question 28

What is Hypertrophy and Atrophy influenced by?

Answer 28

Gender

Question 29

What increases the speed of the growth plates in females?

Answer 29

Estrogen

Question 30

What recieves its share of nutrients first when referring to the runt of the litter?

Answer 30

Brain and central nervous system

Question 31

T or F? Everything in the body grows at the same time, but at different rates.

Answer 31

True

Question 32

The white in bones is what?

Answer 32

Cartilage

Question 33

What is in the Epiphyseal Growth Plate?

Answer 33

Epiphyseal Cartilage

Question 34

When there is a lack of use within bones, what happens? (females)

Answer 34

break down of the bone

Question 35

Hyperplasia exists in what stage of skeletal muscle development?

Answer 35

Cell division

Question 36

What is the name for the cells during cell division?

Answer 36

Myoblasts

Question 37

What is a myotube?

Answer 37

Immature muscle fiber

Question 38

What is myogenesis?

Answer 38

muscle fibers form

Question 39

What is adiopogenisis?

Answer 39

formation of adipose tissue

Question 40

What is myostatin?

Answer 40

Muscle inhibitor (growth factor) that inhibits muscle development

Question 41

What does naturally occuring myostatin mutations cause in animals?

Answer 41

Double muscling

Question 42

What happens with double muscling?

Answer 42

``` Myostatin mutations More muscle fibers Larger muscle fibers Higher percentage white muscle fibers Less body fat High incidence of dystocia Very little intramuscular fat Tender meat ```

Question 43

What is dystocia?

Answer 43

calving difficulty

Question 44

DNA accretion in post natal growth

Answer 44

nuclei incorporated into pre-existing muscle fibers by satellite cells increase muscle fiber's capacity for gene expression and growth

Question 45

Protein accumulation in post natal growth

Answer 45

accounts for majority of muscle fiber hypertrophy | accumulation of myofibrillar protein occurs when protein synthesis exceeds protein degradataion

Question 46

What is a satellite cell?

Answer 46

adult myoblast

Question 47

What is an adipocyte?

Answer 47

a unilocular lipid

Question 48

Lipids account for what percentage of tissue?

Answer 48

76-94%

Question 49

Triacglycerols (triglycerides) account for what percentage of lipids?

Answer 49

90-99%

Question 50

The diameter of an adipocyte is normally?

Answer 50

15-200 um

Question 51

Are adipocyte cells organized in clusters?

Answer 51

Yes

Question 52

What happens during the phases of fattening?

Answer 52

Hyperplasia is followed by hypertrophy | recruitment of new fat cells (hyperplasia) can occur

Question 53

What is increased during fattening?

Answer 53

Adipose tissue and number of fat cells

Question 54

Why is fat in the body accumulated?

Answer 54

It is accumulated because of hyperplasia, and because of the increasing size (hypertrophy).

Question 55

Is growth hormone an FDA approved growth regulator?

Answer 55

No

Question 56

What is differentiation?

Answer 56

acquiring different specialized characteristics

Question 57

Embryonic growth accounts for what percentage of the prenatal period?

Answer 57

15-20%

Question 58

What can happen with stem cells?

Answer 58

Zygote can become anything | cells become more highly differentiated