Forensics Quiz

Case: A twenty-year old man was found supine on Thompson Creak Trail with a bullet wound. The entrance of the wound was on the left lateral side 1cm above the third rib. The exit wound was 5cm above the belly button in the umbilical region. While tracing the bullet path you notice at the entrance the bullet travels in the frontal plane with a 45-degree downward angle. On inspection of the right side of the rib cage by x-ray you observe the 8th rib fractured. Fragments of the bullets are then traced to the final exit wound.

Hypothetic Situation: The young college student went out for a refreshing walk along Thompson Creak Trail. While he looked normal, he was in fact a heavy gambler, and was thousands of dollars in debt. He couldn't pay back the money he owed to people, and was planning to run away after a few days, but he didn't know that he was being watched by one of the gang members. After confirming that he was going to run away, the gang member, who was a bit taller than the college student, shot him from the left side, and thwarted his plans of running away (and killed him too.)

The leading diagnosis is the internal blood loss resulted from the bullet injuring his heart or possibly the aorta of his heart, since the entrance of the wound was on the left lateral side 1cm above the third rib.

Another possible diagnosis might be that the bullet went through his lung, which resulted in loss of air and blood clogging up his lungs. However, this possibility can be ruled out by inspecting the lungs during an autopsy. More possibilities can be that, as stated in the case, while tracing the bullet path we notice at the entrance the bullet travels in the frontal plane with a 45-degree downward angle, and the exit wound was 5cm above the belly button in the umbilical region. This means the bullet might go through his stomach and damaged his stomach. The harmful acids in his punctured stomach might corrode his other organs and tissues causing damage to his other systems in the body, which might lead to his death. The same, after an autopsy and examination of his stomach, we could rule out this possibility. 

Jell-O-- What's in it?

I've been eating Jell-O since I was a toddler, but I've never wondered what's in it. I mean, it was just colorful and wobbly joy that I used to eat. But what's in Jell-O?
   Jell-O contains gelatin, water, sweetener, artificial colors (oh dear), and flavoring. The key ingredient is the gelatin, which is a processed form of collagen, a protein found in most animals. 
   Lots of people have heard that gelatin comes from cow horns and hooves (which it sometimes does, but not mostly), but most of the collagen used to make gelatin comes from pig and cow skin and bones (I don't think I want to eat Jell-O anymore.) These animal products are ground up and treated with acids or bases to release the collagen. The mixture is boiled and the top layer of gelatin is skimmed off the surface. 
   When you dissolve the gelatin powder in hot water, you break the weak bonds that hold the collagen protein chains together. Each chain is a triple-helix that will float around in the bowl until the gelatin cools and new bonds form between the amino acids in the protein. Flavored and colored water fills in the spaces between the polymer chains, becoming trapped as the bonds become more secure. Jell-O is mostly water, but the liquid is trapped in the chains so Jell-O jiggles when you shake it (which was really fun when I used to eat it.) If you heat the Jell-O, you will break the bonds that hold the protein chains together, liquefying the gelatin again. So after researching about Jell-O a bit, I've decided to lay back on the Jell-O. 

Chapter 6 of "Your Inner Fish"

All tetrapods have one head and four limbs arranged in two pairs (for humans, arms and legs, but for other animals, just their legs), a tail, and a variety of other features. But how and why are animals and humans so similar in the embryo stage? And where did this basic body plan come from? Chapter 6 of "Your Inner Fish" explained most of this strange phenomenon.

1. Embryology:  The study of the development of an embryo from the fertilization of the ovum to the fetus stage. The study focuses on comparing different species at their early stage (for example, shark embryos and human embryos.) By comparing these early life forms, scientists are able to find the common structures of various species, and determine how some species may be related. 

2. Germ layers:  Karl Ernst Von Baer, a Russian biologist and one of the founding fathers of the study of embryos,  discovered that there are three layers in embryos (also known as germ layers). 

a. The endoderm is one of the germ layers formed during animal embryogenesis, the process by which the embryo forms and develops. Cells migrating inward along the archenteron form the inner layer of the gastrula, which develops into the endoderm. Endoderm forms many of the inner structures of our bodies, including digestive tract and numerous glands that are associated with it. 

b. The mesoderm germ layer forms in the embryos of triploblastic animals. During gastrulation, some of the cells migrate inward to contribute to the mesoderm, an additional layer between the endoderm and the ectoderm. The formation of a mesoderm led to the development of a coelom. Organs formed inside a coelom can freely move, grow, and develop independently of the body wall while fluid cushions and protects them from shocks. 

The mesoderm has several components which develop into tissues: intermediate mesoderm, paraxial mesoderm, lateral plate mesoderm, and chorda-mesoderm. The chorda-mesoderm develops into the notochord. The intermediate mesoderm develops into kidneys and gonads. The paraxial mesoderm develops into cartilage, skeletal muscle, and dermis. The lateral plate mesoderm develops into the circulatory system (including the heart and spleen), the wall of the gut, wall of the human body, and forms the tissue in between the skeleton and the muscles. 

c. The ectoderm is the outer layer of the embryo, and it forms from the embryo's epiblast. The ectoderm develops into the surface ectoderm, neural crest, and the neural tube.

The surface ectoderm develops into many parts: epidermis, hair, nails, lens of the eye, sebaceous glands, cornea, tooth enamel, and the epithelium of the mouth and nose.
The neural crest of the ectoderm develops into: peripheral nervous system, adrenal medulla, melanocytes, facial cartilage, and dentin of teeth.
The neural tube of the ectoderm develops into: brain, spinal cord, posterior pituitary, motor neurons, and retina.

More Microscope~

During class, we continued using the microscope to observe either an onion root cell or an animal cell (whitefish). We needed to find the different phases of mitosis when looking at these cells, which we mostly did. We compared the different phases that we found to ones that other groups found. For our group, we observed the onion root cell:

Microscope!!

During class, we learned how to use a microscope! By using this new microscope, we observed a dog flea and a plant cell in different magnification settings. Also, we made our own slides --- cheek cells from our cheeks. With the help of such a pro microscope, we were able to observe the cells' structures closely and could tell differences between each stage of mitosis and meiosis.