Comparative and basic biology

Question 1

Laboratory animal sciences is divided into two schools - which?

Answer 1

Basic: The study of animals as a tool. The functions of the animals.

Applied: How does the animal work as a model? Development, application and validation of animals as experimental models.

Question 2

Why are rats and mice so frequently used?

Answer 2

1) they are readily available and cheap
2) they have been used the most in science
3) microbiologically defined
4) they have well characterized strains and stocks
5) vast litterature on them.
6) transgenics well known

Question 3

What charaterises albinism?

Answer 3

1) no active tyrosinase - no melanin
2) visual anomalies and hearing loss
3) audiogenic seizures
4) metabolic anormalities - different doses.
5) Different behaviour

Question 4

What does SPF stand for?

Answer 4

Specified pathogen free

Question 5

What is feccundity?

Answer 5

Combination of time between litters and size of litters.

Question 6

Crepuscular?

Answer 6

Most active at dusk and dawn (also through the rest of the night)

Question 7

What is torpor?

Answer 7

Fast induced decrease in body temperature and metabolism. Also decreases heart rate.

Question 8

What caraterises the rat stomach?

Answer 8

anterior non-glanduar storage and pyloric acid secretion.

Question 9

How does the rodent gut differ from the human one?

Answer 9

Hind gut fermenters - large caecum with microorganisms. Coprophagic.

Question 10

Which one lacks a gall bladder? rat or mouse?

Answer 10

Rat

Question 11

How does the non-primate animals differ from humans in regards to the female reproductive system?

Answer 11

They have two uterine horns = Bicornuate

Question 12

How does the placenta differ between the rodents and humans?

Answer 12

They are both hemochordial = 3 layers of cells separating the maternal and fetal bloodstream. But the vessel organization a bit different.

Question 13

What is special about the rodent vision?

Answer 13

Dichromatic not trichromatic meaning bad colour vision. - but have ultraviolet vision.

Question 14

How good is rodent hearing?

Answer 14

<70 kHz vs <20 kHz in humans - very sensitive to noise.

Question 15

how long is the rodent ovarian cycle?

Answer 15

4.5 days.

Question 16

What is pseudopregnancy?

Answer 16

The female behaves hormonally is if she was pregnant. Halfway through she reverts to normal cycle because of no signal from the fetus. Can be induced in mice be mating from sterile male.

Question 17

What is the postpartrum estrus?

Answer 17

within 12-24 hours after giving birth the female can again become pregnant.

Question 18

Why doesn´t fertilized eggs implant right after birth?

Answer 18

Because of lactation induced delayed implantation. Blastocyst remain free floating and first implant when lactation stops.

Question 19

How long is pregnancy in mice and rats?

Answer 19

19-20 days. (can be detected by weight 12 days in, and 8-10 by proteins in the bloodstream)

Question 20

How long is the lactation period?

Answer 20

21 days.

Question 21

What is the Lee-Boot effect?

Answer 21

Group housed females synchronize cycles. Detection of pheromones through smell.

Question 22

What is the whitten effect?

Answer 22

Addition of a male mouse induces synchronization of estrus within 72 hours. Some females ovulate on day one, more on day 2, and most on day 3 the they are synchronised.

Question 23

What is thee bruce effect?

Answer 23

If a pregnant female is presented with a male that has a foreign smell compaired to that of the male she mated with, she can reabsorp the fetus.

Question 24

How can animal models in biomedical research be catagorized?

Answer 24

1) exploratory models - investigate a mechanism/phenomenom from the bottom
2) explanatory models - test a hypothesis of a complex situation-
3) predictive models - impact of treatment

Question 25

How can you characterize rodent models for human diseases?

Answer 25

1) Induced experimental models (normal animals - develop abnormality fx with toxic substance)
2) spontanous mutant models (spontant udviklet mutation)
3) Induced mutant models (knock-outs etc)
4) Negative models (does not respond to experimental treatment)
5) Orphan models (disease first found in animals)

And combinations hereof

Question 26

What is positive about a small between animal variation?

Answer 26

If there is a small between animal variation the same effect will become more significant. fx Effect/variation

10/1 = 10 = significant

10/5 = 2 = not significant

Question 27

What is the statistical variable D?

Answer 27

its effect/variation = (mean(experimental)-mean(control)/variation)

If the D value is small we can get away with small group sizes.

Question 28

What parameters are used for charaterizing and standardizing laboratory animals?

Answer 28

1) health
2) genetics
3) environment
4) husbandry
5) experimental procedures and design

Question 29

Experimental factors related to rodents:

Answer 29

1) size - high metabolic rate - function of body weight

2)

Question 30

How do you calculate the metabolic rate of mammals?

Answer 30

3.8 * bodyweight^-0.25

This can be used to calculate doses

Dose 1 = constant * BW^-0.25
Dose 2 = constant * BW^-0.25

Divide by each eacher and isolate dose.

Question 31

Factors related to the animal which are important to consider when taking samples:

Answer 31

1 ) Size, sex, age weight
2 ) Growth rate and lifespan
3 ) ovarian cycle, pregnancy, number of offspring
4 ) Biological rhytms
5 ) genetic characteristics
6 ) microbiological status
7 ) adaptation (mostly monkeys and animals that can be stressed after capture)

Question 32

What are the arrive guidelines?

Answer 32

Guidelines made to increase reproductibility of animal research.

Question 33

What temperature does mice prefer?

Answer 33

30 degrees when not doing anything, Don´t care when they are active.

Question 34

Which factors may influence the behaviour and physiology in the housing facility?

Answer 34

1 ) temperature
2 ) light
3 ) sound