End of Semester

I will honestly say I do not like my performance in this class. Senoritis hit me hard, and I let it take over my life. I have so many late assignments that I need to spend time on to turn in. Oh, my life.

This class was so much fun! The labs that we did were very interesting and thought provoking. The topics we covered under the blanket of developmental biology were wider than I had imagined! And the people in the class just made it so much more fun! I absolutely love going to this class every day.

This difference I've had with this class is that it doesn't really cover topics I've touched before. With every other class, I was able to have a great amount of background knowledge to make the learning a lot easier. But with this class, that wasn't the case. I was actually learning from scratch, which made it harder for me. I had to learn the best way to study for the class. Even though I still don't know as much as my classmates and that I feel like I'm behind, I'm happy for this experience. It's preparing me for the same experience I have throughout medical school.

I am so grateful for Dr. V. She has been very understanding and flexible with me. It's so awesome to have a professor that understands that so much happens outside of being a student. She is deeply appreciated!

Overall, I am grateful for this experience this class have given me.

Floppy Baby Syndrome

What an odd name, right? It is also known as Floppy Infant Syndrome. Take a wild guess at why it is called that.. When the baby is born, it looks and feels like it is a ragdoll. You can see that in the picture below.

The condition that the baby has is hypotonia, decreased muscle tone. As the baby grows, it will have delayed motor development, bad motor control, and possible weakness. There is a myriad of causes for this condition. If something goes wrong at any part of the development of the nervous system in utero, then may develop. There may be central disorders or peripheral disorders that cause this. Some are listed below for each:

Central Disorders: intracranial hemorrhage, metabolic errors, genetics, or even chromosomal abnormalities

Peripheral Disorders: anterior horn abnormalities, meuromuscular junctions, muscle, or even a peripheral nerve

Unfortunately, there is no treatment or cure for this syndrome.


http://pediatrics.uchicago.edu/chiefs/DBP/documents/reading%20pdf/Hypotonia.Peredo.pdf

The Brain

Use the photo above in reference to the definitions given below.

Pons - This is a part of the brainstem. It is located between the midbrain and medulla oblongata. The pons develop from the metencephalon. Some of its functions include the sense such as taste and hearing, and touch. It also functions in equilibrium, mastication, lacrimation, and salivary secretions.

Medulla Oblongata - This is the lower part of the brainstem that is located underneath the pons. The medulla developed from the myelencephalon. Some of its functions include roles in the autonomous nervous system: reflexes, pressure receptors, chemoreceptors, and regulation of the heart.

Midbrain - This is the upper part of the brainstem. It develops from the mesencephalon. It produces dopamine in the substantia nigra. It also plays a role in the motor system.

Cerebellum - This organ is located on the dorsal side of the brainstem. It sits posterior to the cerebrum. It develops from the embryonic metencephalon, just like the pons. The cerebellum functions in happiness, motor learning, and motor control.

Cerebrum - This is the major part of the brain. It develops from the telecephalon. This is a huge part of the brain. It's many subsections would have numerous functions. But in general, the cerefrum functions in motor functions, processing senses, smelling, speech and communication, memory, and learning.

Trisomy 18

There is a beautiful couple in my church that had a baby. They had a little baby girl named Arielle. Unfortunately, little Arielle was born with a genetic disorder: trisomy 18.

Trisomy 18 is also known as Edward's syndrome. This condition is where there is an extra 18th chromosome. For some reason, this syndrome is found mostly in females than males.

There are a host of issues that come along with that extra chromosome:

• heart defects
• mental disability
• growth and developmental issues
• breathing and feeding problems
• joint contractures
• cleft lip/palate
• spaced eyes
• and many other problems

Half of the children that are born with this syndrome die within the first week. The oldest one has lived was to age 10. I can say that baby Arielle lived for 5 months and 1 week. She beat a lot of odds. She ministered to hundreds around her. While she never lived a full life, she will have an eternity when Jesus returns.

Fetal Alcohol Syndrome

Fetal Alcohol Syndrome occurs when a pregnant woman drinks while pregnant. Alcohol is a teratogen. Some women know they are pregnant when then do it while others do not. Those that do not know may engage in drinking during the critical early parts of the pregnancy. And since the mom's blood supplies nutrients and such, the alcohol crosses the placenta to the baby.

The problems it causes in the baby are growth stunting, CNS damage, and distinct facial features. The picture above shows examples of the facial features it causes. The damage to the CNS can be structural, functional, or neurological.

For a child to be diagnosed with the disease, the baby's height or weight would have to be terribly low, they must have the facial deformities characteristic of fetal alcohol syndrome, and have structural or functional CNS problems.

Dextrocardia

Dextrocardia is a condition where the heart is located on the right side instead of the left side. Below is an image of the condition. Not just the heart itself, but also the associated blood vessels.

What is interesting is that is a genetic disorder. It is autosomal recessive. Oddly enough, it can also be X-linked. Those that have it are actually normal phenotypically. Most don't find out about their condition until later in life or they have other pressing medical issues. This actually makes heart transplants very difficult. Doctors would have to use extra measures of taking a normal person's heart and associated vessels and tailoring it to the person with dextrocardia.

An Awesome Lady with Cool Research

On Monday, Dr. Oluwatoyosi Muse visited for our Departmental meeting. She presented on her research. The title was "Sequence Selective Recognition of Biologically Relevant RNA by Cationic". It was an incredibly interesting presentation and I thoroughly enjoyed it.

But what was interesting is that for part of her experiment, she used HEK, which are human embryonic kidney cells. I should have asked why she used those cells. Maybe because they were able to highly replicate, or the destination for what she was testing was in there. Either way, it was cool that she has able to retrieve human embryonic kidney cells and test them.

Types of Cell Adhesion

Desmosomes - These are also called macula adherens. An appropriate description would be that they are spot welds. The proteins that make them up include desmogleins, keratin and cadherins. They help in the resistance of force.

Zonula Adherens - These junctions are also known as adherens junctions. They include cadherins, catenin, actin and actinin. Such junctions are strong and are used for anchorage















Zonula Occludens - Also known as tight junctions. They have protein complexes that form to create an impenetrable membrane between cells













Gap Junctions - Also known as macula communicans. They are made up of hydrophilic channels. Such channels help in their function of connecting the cytoplasm of the cells











Hemidesmosome - They are very similar to desmosomes. What differs is that instead of desmogleins, desmopenetrin proteins are used

About Midterm Time

I am struggling. I am struggling to stay afloat this semester. So much is going on in but mostly outside of the classroom. People are pressuring me with many other tasks when I'm just trying to take care of my own business. All I can do is sleep just to stay sane. Ugh.

Overall, I'm not doing well in the class. I'm behind in assignments. But what is really bothering me is that I haven't found a great way to study yet. Reading the book helps, but I'm not retaining the information very well. I need to figure this out quickly. Or maybe I'm doing alright. Who knows. Maybe my grade on the first exam will be able to provide me with some insight.

Please pray for me.

Sea Urchin Fertilization

On Thursday, I was able to watch fertilization occur!

In lab, we used sea urchins (SU) to watch fertilization. I scooped out my own sea urchin from the tank and put it in the holding bin. While there, named the SU Terry (a unisex name). As Terry was getting acclimated to that water, I got a cup filled with sea water, a petri dish, a needle, potassium chloride, and paper towels. I also put on gloves. It was time.

I got Terry and placed it on the petridish. I turned it over to expose its bottom. Poor thing was not happy. The needle was filled with 1 milliliter of potassium chloride. Angling the needle between the needle portion and the opening, I injected Terry with 0.5 milliliters of potassium chloride. Poor thing was in pain and writhing around. :(

After about a minute, the gametes started flowing out of Terry. It was white, so we determined that Terry was in fact a boy! So we collected the rest of the sperm in the petri dish.

To watch fertilization, I got another group's eggs and put 1 drop of it on a microscope slide and covered it with a cover slip. Then, I got a small beaker and filled it with 10 ml of water. I then pipetted some of the sperm in the water to activate it. After focusing on the eggs under the microscope on the 40x objective, a drop of sperm solution was added to the slide. Looking at the slide, I was able to see the sperm vigorously swimming around. Looking at the eggs, it was clear to see which sperm fertilized eggs. It was also cool to see the fast block prevent polyspermy. The most awesome part was watching the fertilization envelope develop.

Just to watch what we have been learning occur before my very eyes was beautiful. It helps to make a lot of the concepts make sense.

Craniosynostosis

Craniosynostosis is a condition where an infant has premature fusing of the sutures in his head, leading to ossification. What is interesting is that the ossification is of mesenchyme. The sutures that hold the bones of the head together are made from fibrous tissue. But they have two more important functions: to allow the baby's head to fit through the birth canal, and separation of the bones that make up the skull cap.

Membrane ossification of the cranial bones occurs during the first few weeks of fetal development, the first trimester of pregnancy. The 4 bones that make up the skull cap are the frontal, parietal, and occipital (anterior + squamosal). What determines the fusion of these bones are many factors such as transcription factors, EM molecules, and cytokines. The precise process is not known. A combination of genetic and environmental factors cause craniosynostosis. Below is a table that discusses the types of craniosynostosis and the characteristics associated with them. The table also comes from the reference below.

BUROKAS, LAURA. "Craniosynostosis: Caring For Infants And Their Families." Critical Care Nurse 33.4 (2013): 39-51. Academic Search Premier. Web. 21 Sept. 2014.

Some Unfamiliar terms

Theca cells - These make up a layer of ovarian follicles. One of the layers of theca cells produce androstenedione, which is converted to estradiol by aromatase.

Zona Pellucida - It is a membrane made of glycoproteins that surrounds the cell membrane of the oocyte. It is the structure that sperm bind to and start the acrosome reaction.

Corona Radiata - This is the inner layer of the cumulus oophorus. It provides essential proteins to the developing cell

Graafian follicle - also known as an antral follicle; It is a stage in folliculogenesis where the antrum forms next to the oocyte.

"Mom... What Am I?!"

People don't usually ask what they are in terms of gender. You know definitively if you are a male or female. But this wasn't the case in the Law and Order: SVU episode entitled 'Identity'.  

In this episode, the suspects were a set of identical twins that were a boy and girl. Honestly, that should raise a red flag right now. Identical twins can only be one gender. So that fact that it was both a boy and girl should suggest that some gender reassignment has occurred.

When the twin boys went in for circumcision, the doctor botched one of the twins circumcision. This led the parents to then raise that child as a girl. It was fine at first, but as the girl reached puberty, she found herself liking girls. She was very confused as who she was because she felt like a boy on the inside. She soon found out that she was actually a boy, and the 'vitamins' her parents have been giving her were actually estrogen pills. So the girl stops taking the pills so she can go back to her original gender: a boy.

It was an interesting episode that discussed the science and ethics behind gender roles and reassignment.

http://lawandorder.wikia.com/wiki/Identity_(SVU)

Expectations and Fears

So.... I'm both excited and scared about Developmental Biology. I absolutely love biology, but this unchartered area of knowledge frightens me a little. Honestly, I don't know one bit of information about it. But of course, that's okay.

I'm so excited to learn about it. I don't quite know what topics we are going to cover, but I'm open to anything and everything. I'll post another reflection at midterm and at the end.