A naked look inside the nucleus at the chromosomes… (Day 60)

Human Chromosome Genetics Microscope

Another Friday, Milk hygiene today was looking at the properties of tinned milk and condensed milk. I am now at the stage where I feel like I know more about milk than any single sane person would ever want to. Some of its useful, some not so useful, and then theres the plain interesting such as how many tests are carried out. Some of its scientific such as the massive list of potential bacterias, and then theres the not so scientific such as the “Cooked Taste” that steralised milk has.

Now genetics today we started looking at the Chromosomes that basically contain the code for all living things. Its amazing how something so small can determine whether you are male or female, in fact determine everything about you. Now lets make it a little more interesting, this is what you look like when everything else is stripped away…

Human Chromosome Genetics Microscope
The Chromosomes from the nucleus of a human cell… Yes, this is what we look like inside!

Now obviously this cell nucleus has been increased, this is done by using a hypotonic solution which causes the cells to swell whilst leaving the centromeres intact. This allows you to view the chromosomes under a normal light microscope as above (this image is at 1000x magnification if I remember correctly).

When examining the chromosomes we use something called the karyotype which is unique to each animal species (the number of chromosomes is different between species too). Basically the different chromosomes are arranged on different rows representing groups based on shape, size and where their center is. Using this it is then possible to identify the species, and even determine whether it is male or female from looking at the sex chromosomes. Here are the chromosomes from a Rat…

The chromosomes from a Rat in Genetics
Rat Chromosomes under the microscope

And here are the chromosomes from cattle (cows/bulls etc), if you click on the picture you can see a bigger version as well! 🙂

Cattle Chromosomes under the microscope in Genetics
Cattle Chromosomes under the microscope

A few weeks ago you may remember me talking about the bone marrow and how it was harvested from the femur of the mouse. We came back to it this week in addition to the bone marrow and blood collected from the cow. Today we prepared these for microscopic examination removing them from the solution and staining them (they are not naturally pink/purple) onto slides.

Histology Blood and Bone Marrow Stained Slides
Blood and Bone Marrow slides prepared for the microscope

These then were examined under the microscope, and I did actually find a cell in the metaphase stage of mitosis in the bone marrow I collected from the mouse! Looks pretty cool right (the small circle of purple chromosomes)? Amazing how something so small can control something so complicated…

My mouse chromosome in metaphase stage of mitosis
Mouse chromosome in Metaphase stage of mitosis

Hopefully you have enjoyed todays diary as much as me! Now I really must sleep, Friday always is so long, and by the end I am always so exhausted I think it is because the week catches up with me.

Blood, vessels and the Lymphatic system… (Day 42)

Horse blood smear with erythrocytes

Start of my 6th week in vet school (only 7 more weeks left in this semester), this week is just 4 days as Friday is our Matriculation Ceremony where we official become students of the school and are presented with an official certificate to say that we are officially students. Its a formal ceremony so hopefully should have some photo’s for you showing just how well I can scrub up when I need to (saying that my suit needs drycleaning…)!

Anyways this morning was Histology, we’ve now moved onto blood cells and spent it discussing the production and identification of the different types of cells within the blood and the differences between the species. The practical session this was put into practice and we had the chance to look at the different smears. The biggest difference between mammals and birds is that the red blood cells (erythrocytes) don’t have a nucleus in mammals but do in birds.

Horse blood smear with erythrocytes
Horse (mammal) blood smear with no nucleus in red blood cells

And then you have an avian blood smear with the nucleus in red blood cells and also having a oval shaped rather than the round shape.

Avian Blood Smear with erythrocytes
Avian Blood Smear with oval shaped erythrocytes with a nucleus

There are many other cell types within the blood which we also looked at. Anyways after this it was time for Physiology where we looked at blood vessels along with blood pressure and the lymphatic system which takes care of the leaky plumbing within the body. The biggest of these vessels with the vena cava vein is up to 3cm diameter and the aorta is 2.5cm diameter… The shocking number however is that the cross sectional area of the capilary system within the body is around 2500 square cm’s! Now thats a lot of space!!!

Anyways, back to revision as I have my first microbiology credit test tommorow!

Genetics, Milk Tasting, Blood and Bone Marrow…(Day 39)

My first blood sample from a cow in vet school

Today has been amazing! I don’t know exactly where to start so I guess I will start at the beginning! Genetics started with more on the chromosome (it is a rather large and complex yet crucial part of all things living) and mapping of it, to put it simply if each strand of DNA was unravelled it would be over 2m long, yet fits into a structure of just micrometers…

After this it was time for milk hygiene, today was looking at mastitis and then the different nutritional properties of milk (fat content, protein, lactose etc) with the processing methods and how this affects the taste.

The most basic test for mastitis can be carried out on the farm and involves taking a small amount of milk and mixing it with the same amount of Mastitis test solution which will become a gelatinous mass if positive (like as follows)

Milk with mastitis test solution
Milk with mastitis test solution

We had four different samples to work from, 3 of which where UHT (Ultra High Temperature treated) milk which means that the milk was steralised by boiling at over 135 degress with full fat, semi-skinned and skinned  samples of this milk. We then also had a sample of semi-skinned pasteurised milk which was heat treated at 72 degrees for a minimum of 25 seconds to kill of any harmful bacteria. Now its logical that when you heat milk, you cook it which may change the content, smell, look and flavour. I personally found the UHT samples had a stronger smell, and a much stronger taste compared to the pasteurised sample. In the UK it is more common for milk to be pasteurised which whilst it has a shorter shelf life, it does contain more natural goodness in proteins and vitamins than UHT milk as the temperature also removes some of these from UHT in addition to bacteria. Considering its always been a something I’ve never actually thought about it definately has given me some food for thought. Now towards the end of this practical we had a stream of horses and riders go past the lab window. So once it ended I went to find out more…

This was the Hubert Ride to celebrate Saint Hubert the patron saint of hunting, now the ceremony was in Slovak so I did not understand much of it, however the horses were definately beautiful to look at!

Ardo with Saint Huberts Ride SlovakiaAnd there was a horse drawn carriage as well for the important people (who I did not recognise and who were not introduced) to arrive in. A speech was then given which was probably heard only by those giving it as no sound system was used.

Saint Hubert SpeechWe decided to leave here as there is only so much time you can spend looking at horses and we needed to get some wellies for the genetics practical. We managed to find a hardware store which had them relatively cheap (at 9 euros) so got these and then headed back to grab overalls for the practical.

This afternoons session was on the sampling of blood and bone marrow from the cow for chromosomal analysis. Something I was really pleased with was that there was an additional independant vet from outside the university (and in fact from a different country as well) to ensure the welfare of the animals used in the practical was maintained. Obviously as vet students there is a need to work with animals, however before doing so today we had a lecture, then a demonstration of the bone marrow technique in the anatomy museum, before then also a demonstration on a live animal.

The first sampling technique was that for blood collection from the jugular vein, the hair was clipped and the skin cleaned before collection to prevent infection. I struggled initially as I did not realise how deep under the skin the vein actually was however I did eventually get my first ever blood sample from a cow (yay!).

My first blood sample from a cow in vet schoolAfter this there was a demonstration on how to collect the bone marrow. Sedation and analgesia (pain relief) is used with bone marrow collection to ensure that the animal feels no pain. Signs of effective sedation are drooling and relaxation of the muscles. In the cow this is taken from the hip bone, and there is a small notch where the bone is thinner that is used for insertion of the collection needle. Now to enter the bone you have to gently tap the top of the needle until you can feel it enter the bone marrow cavity, you then remove the stylet (the needle inside the collection tube) and check the tip of this has bone marrow on which is thicker and more fatty than normal blood. You then attach a syringe to aspirate the bone marrow for analysis later.

My first bone marrow sample in vet school
My first ever bone marrow sample

Ok so maybe I need a hair cut :p However I was really pleased with myself for getting my first medical procedure spot on. I am also cat sitting this weekend so when I got back to dorms after a shower went to collect my new friend. Hope you’ve enjoyed todays post, no animals were harmed during todays experience, yet I have learnt so much!!! 🙂