Exam 1 Flashcards

1
Q

Define Growth

A

An increase in size by the animal

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2
Q

Define hyperplasia

A

An increase in cell numbers

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3
Q

Define hypertrophy

A

An increase in cell size

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4
Q

Define compensatory growth

A

Rate of growth significantly increase after a prolonged feed restriction

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5
Q

Name the 4 phases of a growth curve in order

A
  1. Lag phase
  2. Accelerating phase
  3. Decelerating phase
  4. Plateau phase
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6
Q

List 2 factors that can affect the growth curve

A
  1. Genetics
  2. Nutrition
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7
Q

In 3 sentences, describe the mechanism of how compensatory growth happens

A

Feed restriction causes digestive organs to shrink in size. When organs shrink, maintenance energy requirements are decreased. This decrease results in greater feed efficiency

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8
Q

Draw the growth curve and the curve for compensatory growth

A
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9
Q

Draw and label the growth curves for bone, muscle, and fat tissue

A
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10
Q

What is considered the gold standard for estimating body composition of cattle?

A

Comparative slaughter

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11
Q

Describe the method of how comparative slaughter is done in 3 sentences

A

A group of similar animals are slaughtered together at different stages of growth curve to estimate changes in body composition. Each carcass is put in a grinder and made into a paste. The paste is sent to a lab for nutrient analysis.

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12
Q

Describe the method of how carcass dissection is done in 1 sentence

A

Dead animal carcass is cut with a butcher knife to separate bone, muscle, and fat tissue

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13
Q

Write one disadvantage of the carcass dissection method

A

Fails to measure internal marbling fat

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14
Q

Describe how the sawdust method is done in 2 sentences

A

Animal carcass is frozen and a saw is used on frozen carcass. Sawdust is then collected and subjected to lab procedures for nutrient analysis

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15
Q

In 3 sentences, describe how DEXA estimates body composition

A

The animal is exposed to x-rays at 2 different wavelengths. Each tissue in body absorbs radiation differently. The amount absorbed by different tissues is used in math formulas that estimate % of each tissue.

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16
Q

Write 1 advantage of the DEXA method

A

The animal is alive and multiple measurements can be taken along growth curve

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17
Q

Write 1 advantage and 1 disadvantage of using CT scans to estimate body composition

A

+ ~ most accurate
- ~ expensive equipment

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18
Q

In 2 sentences, explain how K-40 is used to estimate body composition

A

It is a form of K that is a radioactive isotype which makes it less common. It is soluble in water so the more muscle you have, the higher the K-40

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19
Q

In 2 sentences, explain how the Deuterium dilution technique is used to estimate body composition

A

A known amount of Deuterium is injected into the blood. After 24 hours, the amount of Deuterium is measured in blood.

More muscle = less deuterium

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20
Q

In 2 sentences, explain how electrical conductivity can be used to estimate body composition

A

An electrical current is put on the animal and conduction of electricity by body is measured. Animals with more muscle conduct more electricity

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21
Q

In 2 sentences, explain how ultrasound can be used to estimate body composition

A

A probe is waved on animal skin and emits sound waves which is used to generate a 3D image. Bone has the most dense, then muscle, then fat

22
Q

What is your favorite method of estimating body composition. Explain why.

23
Q

Describe the process of prenatal development starting with the zygote and ending with the fetus. WILL GIVE US A CHEAT SHEET. JUST HAVE TO COPY ONTO TEST

A
  1. After reproduction, zygote is formed by a sperm fertilizing an egg
  2. The zygote divides into 2 cells, then 4, and so on until 32 cells are formed. Between 4 and 8 cell stages, the cells are called a blastomere
  3. At 32 cell stage, zygote forms into a morula
    Day 4 of pregnancy
  4. On day 5, the morula moves into uterus and undergoes morphogenesis
  5. On day 6, the morula becomes a new structure, blastocyst
  6. On day 8, implantation occurs, the blastocyst is pushed into uterus lining (endometrium) of pregnant female.
  7. On day 10, the blastocyst changes shape again and becomes the embryonic disk
  8. On day 21, gastration occurs and continues until day 63 of pregnancy
  9. Prenatal development continues until the 9th month of pregnancy
24
Q

Name the 3 germ layers of the embryo and list 2 tissues types or organs that arise from each layer

A

Ectoderm - skin and mammary tissue
Mesoderm - muscle and fat tissue
Endoderm - digestive and respiratory organs

25
Freematin calves
Twins are different genders Male releases masculine hormones that stunt ovary development in female causing her to have male genetalia and being sterile
26
List 2 functions of the nervous system
Control body movement Control endocrine system
27
Does growth of nerve tissue occur prenatally OR postnatally?
Prenatally
28
List the 5 types of Glial cells in nerve tissue and describe what each one does.
- Schwann cells ~ Maintain the myelin sheath in PNS - Oligodendrocytes ~ maintain the myelin sheath in CNS - Anchor cells ~ holds neurons in place - Astrocytes ~ part of the meninges barrier - Microglia ~ scavengers that remove dead cells
29
List and describe the 5 steps that affect development of the nervous system.
1. Cell division - stem cells in ectoderm divide 2. Migration - cells move to where they need to be 3. Differentiation - cells acquire their functional characteristics 4. Synapsogenesis - neurons form connections with one another 5. Apoptosis - neurons commit suicide
30
What specifically does the neural crest become?
PNS
31
What specifically does the neural tube become?
CNS
32
Describe the migration of immature nervous system cells during the development of the 6 layers of the brain.
They climb on each other like ladders
33
Why do so many neurons undergo apoptosis during prenatal development?
They fail to form connections
34
State 1 reason why it is important to study bone in animal agriculture.
Bone development leads to muscle development
35
Describe 2 functions of bone.
Provide structural support Allow body movement
36
Explain the difference between ligaments and tendons.
Ligaments - connect bone to another bone Tendons - connects bone to muscle
37
Explain how the Periosteum is helpful for nourishing bone cells.
It contains blood vessels that carry oxygen and nutrients to bone cells.
38
Write a paragraph describing the differences between the spongy and campact layer of bone.
Spongy - less dense, made up of several small beams, contains red marrow (red blood cells are made) Compact - contains a central cavity filled with yellow marrow (filled with fat), contains more minerals
39
Write a paragraph describing how osteoblasts build bone
They start by secreting a protein matrix that serves as the organic foundation of bone As they secrete this matrix, they become trapped in it by building a wall. Once matrix is formed, they collect minerals from blood and lay them on top of matrix They are deposited as Hydroxyapatite Crystals. When mineralization is complete, the osteoblasts are now called osteocytes
40
Write a paragraph describing the rold of osteoclasts in bone remodeling.
They break down bone by sitting on surface of bone secreting acid to break apart the mineral crystals. They also use an enzyme called collagenase to break down the protein matrix. When the existing matrix is gone, the osteoclasts leave and the osteoblasts come in to build something new.
41
Explain why the Chihuahua dogs are so much smaller than the Great Dane.
Small dog breeds have a genetic mutation that prevents them from producing IGF-1. The larger breeds produce plenty of IGF-1 and have more bone growth
42
What does the hormone "Calcitonin" do?
Increases calcium deposition in bone
43
What is the difference between Rickets and Osteoporosis?
Rickets - in children Osteoporosis - in adults
44
Osteogenic cells
immature stem cells that give rise to bone cells
45
Osteoblasts
cell that build new bone
46
Osteocytes
housekeeping cells of bone tissue
47
Osteoclasts
cells that break down existing bone
48
Bone lining cells
lazy cells that just sit on surface of bone
49
Which germ layer of the embryo does bone tissue arise from?
Ectoderm
50
Describe the process of bone growth, starting with the cartilage outline and ending with mineralization of the growth plates. WILL GIVE US A CHEAT SHEET. JUST HAVE TO COPY ONTO TEST
1. The cartilage produced from chondroblasts serves as a model or structural outline for bone creation 2. The osteoblasts sit on top of cartilage model and secrete matrix proteins 3. The osteoblasts colled Calcium and Phosphorus to create mineral crystals that get deposited on protein matrix 4. When matrix is mineralized, the osteoblasts becom osteocytes 5. After birth, there are growth plates made of cartilage at each end of a bone that move in opposite directions 6. The growth plates lay down new cartilage which will be used to make bones longer 7. New osteoblasts sit on top of cartilage and produce new bone 8. When animal reaches maturity, the growth plates become mineralized and stops further bone growth
51
List and describe the 3 phases of bone healing.
1. Inflammatory - blood supply to site of damage increases so that more nutrients and osteogenic cells can go there 2. Repairative - osteoblasts build new bone to repair fracture. This forms a rough Callus 3. Remodeling - the bone is used and osteoclasts help change the foundation so it can be made stronger