T e purpose of this lab is observe the different stages of embryonic development for mammals, an d rats play as a good specimen because they are not too small that it is hard to observe the stag SE and they are not too big that it would be difficult to navigate around the specimen’s intern al organs. In addition, rats typically hold a clutch size of around 12 so if any mistakes arise during Eng dissection of the sac, there are more opportunities to get a sample embryo that isn’t t o damaged. In order to achieve this goal, students will first observe the different organs of the packmen in order to understand the functions of each organs.
For example, after bobs Irving the mouth cavity, a student can predict what type of diet rats have by recording observation ions about the specimen’s teeth and palates. After students observe each organ, and their contra button to each organ system and contribution to the survival of the rat, students will then awns ere and explain the reasons for the structures of the organs. For example, when observing the e lungs, students will find that the inside of the lungs are elastic and spongy, students will ha e to explain why the lungs are constructed in that way.
Once students have recorded and explained their findings on the organs of the moth specimen, students will move on to observing the embryonic development of the rat embryos/ fetus. Each group will have a specimen with an embryo at different stages of development. Each group will be responsible of locating the ovaries, and cutting pope n the embryonic sac in order to obtain an embryo sample. Students will then observe the d efferent stages of the embryonic development, noting the difference between each stage and understanding what may be occurring during these different stages.
Data: Stages Development of organs Distinguishable head and tail location No placenta found yet A placenta has developed Umbilical cord connect to embryo Embryo developing limbs Skin becomes thicker Internal organs developing Further development of internal organs due to increase in size More distinct limbs and tail Nose and ears developing Immense increase in Skin becomes really wrinkled External features Head development Toes under development have become really Further development of limbs Eyes become more developed
Detailed, Fetus has Mouth and Eyes developing Excess of skin developed grown into its excess Further spinal cord development External features more distinct of skin
Questions:
Based on the teeth and mouth structures, what type of organisms do you think that the rat feeds upon? The rat has a longer lower Jaw teeth than upper Jaw teeth, and most likely feeds on s mall nuts, fruits and smaller organisms such as smaller rodents.
- Why would the rat be considered as a collocate in its classification? A rat would would be considered as a collocate because the rat’s blood is runs thro ugh blood easels and the rat’s organs are individually covered by their own distinct layer of pep thulium.
- Why does the rat contain a multiplied liver? The liver is used in order to help detoxify and regulate the substances within the blob do as well as use bile in order to break down lipids for energy.
- A multi lobed liver would be necessary since a rat’s diet consist of various items that may be toxic, and as an active organism, the rat would require a consistently high metabolism to support it’s lifestyle which requires a lot of energy.
- How would describe the endoderm of the small intestine and why is it adapted in s chi a way? The endoderm is quite bumpy, which indicates intestinal villous.
- The small intestine is adapted that way in order to increase surface area and help with absorption of nutrients, the f aster absorption would help support a high metabolism lifestyle with continuously rapid a mount of nutrients diffusing into the blood.
- Why do you think the pregnant rats have more of these fat tissues than most rat SP Siemens? Pregnant rats would have more fat tissues than most rat specimens because they ARQ Eire a larger fat reserve in order to provide energy that could both support the mother and he multiple embryos.
- Can you distinguish between the medulla and cortex regions of the kidney?
- How do they differ in their endocrine functions? Yes the medulla and the cortex regions of the kidney are distinguishable because the cortex is the outer layer of the kidney while the medulla is within the kidney. The cortex is rest opinions for filtering metabolic waste from the blood while the medulla is responsible for regulate Eng the blood salt levels.
- Why is the diaphragm so muscular? Since this organism works on a negative pressure system, the diagram has to be muss ocular
