Epithelium, and the mechanics of Blood (Day 21)

Simple Columar Epithelium

Welcome to Monday the start of my third week at Vet School here in Kosice, Slovakia. The weather is getting cooler yet still remains a lot warmer than back in the UK and there is still the same buzz as three weeks ago when I wake up to be here! This week is going be interesting as the workload is increasing and week 4 has multiple credit tests looming.

Today is Histology, one of my favourite subjects, and we spent the lecture talking about epithelium (the fancy name for skin) and the different types of cells that line different organs of the body. We’ve been warned that this will come up in the credit test so its something I will revise again. In the practical we put the theory into practice and looked at different examples under the microscope as its one thing knowing it, and another recognising it in a tissue section. We also had to draw a representation of what we saw so here’s some of my attempts 🙂

Drawing Epithelium in Histology

These translate roughly into a microscopic image such as this which shows folds of tissue lined with simple columar epithelium. The dark lines is where the nucleous of the cells get stained darker, and in this type of tissue they line up next to each other in a polarised (towards one end) way.

Simple Columar EpitheliumAfter Histology it was time for Physiology, today was on the composition of blood. From memory now about 55% of blood is plasma, 45% is Red Blood Cells and less than 1% is White Blood Cells and platelets. Plasma consists of around 93% water and 7% blood plasma proteins (mainly Albumins, Globulins, Fibrinogen and regulatory proteins).

There are several different feedback mechanisms for blood which I think is pretty cool, the level of CO2 in the body affects blood pH so the regulation of blood pH is actually tied into respiration! Anyways so Erythrocytes or Red Blood Cells (RBCs) form 99% of blood cells and have a concave shaped disc to increase the surface area for gas exchange. RBC’s lack a nucleous and have a flexible structure so that they can change shape to pass through tiny capilaries that are half their size. Its amazing how when you look at RBC’s you also consider the age as younger RBC’s are more flexible and more efficient than older RBC’s.

In terms of the average life spans of RBC’s in days here are the numbers:

  • Cat – 70
  • Cow – 100
  • Goat – 125
  • Pig -65
  • Chicken – 28
  • Dog – 120
  • Horse – 145
  • Sheep – 110

Within erythrocytes 62%-72% of the cell is water, with around 35% solid (which breaks down into 95% haemoglobin, and 5% proteins, lipids, vitamins, glucose and enzymes). Basically Iron is the main component which I think is pretty cool as when RBC’s die their contents are recycled by the body so all the amino acids and iron from the RBC is processed again by the body.

The rest of the evening I spent looking at basic chemistry which is problem for me however I am getting to understand it better. Unlike my undergrad here I have to understand the proteins and chemical structure of the cells in addition to what the different cells are and whilst it is interesting I am not the strongest on Chemistry!