Thursday, 13 August 2020

About blood

Blood forms the transport system of the body. It flows continuously to supply oxygen and nutrients to tissue and to remove waste products. It also plays an important role in the defense against pathogens in the body and ensures a constant body temperature. Blood is an important transport medium for hormones. So blood literally means life!

About half of the human blood is plasma. Blood plasma mainly consists of fluid and proteins. The other half of this blood consists of blood cells, namely: red blood cells, white blood cells and platelets. For example, the red blood cells transport oxygen and carbon dioxide through the body. The white blood cells make harmful substances and pathogens recognizable and harmless. Platelets provide crusting to a wound.

Tuesday, 11 August 2020

Rotifers - Some of the smallest animals on earth

Rotifers are some of the smallest animals on the planet. Most measure under 500 microns, but their size can range from only 50 microns to around 2 mm (2000 microns). They are some of the most common microscopic animals, living all over the world in all kind of environments, like freshwater, saltwater, in moss on trees and in the soil underneath your feet. Rotifers are made up of roughly 1000 cells, some of which are specialized to form organ systems. Despite their incredibly small size they have eyes, a small brain and nervous system, and a dedicated digestive system just like us.

Friday, 7 August 2020

A find on the beach

The shells or shields on the back of the various species of cuttlefish Sepia spec. consist of brittle lime (sometimes also referred to as Sea Foam) and are softer on one side than on the other. There is gas between the layers of lime, so that they float and often wash up on the beach.

Cuttlefish are good swimmers who can cover large distances. Sometimes animals wash ashore on the coast, but more often loose back shields. They have good buoyancy and can wash up on the beach at a great distance from the place where the animal died.

Friday, 31 July 2020

Lumbriculus variegatus - The blackworm

Lumbriculus variegatus, more commonly known as a blackworm, is an oligochaete worm found in many freshwater habitats across Europe and North America. It is technically not microscopic, but very small and to see the details and internal anatomy, we have to use a microscope.

Blackworms are only about a millimeter in thickness, but they are able to reach a length of up to 10 centimeters. Blackworms eat things like microorganisms and decaying plant material. To digest its food, the worm has a dedicated digestive tract running down the center of the body. This is like a miniature version of the human digestive tract and works in basically the same way by squeezing ingested food through the tube with rhythmical massaging movements called peristalsis (see video further down).
Another clearly visible structure in the worm is its circulatory system. The animal lacks a true heart, but instead pumps blood through the blood vessels with several pairs of muscularized vessels able to contract and work as a heart.

Wednesday, 22 July 2020

Myriophyllum beautiful but a nuisance

Myriophyllum or Red stem is a water plant that prefers to take root on the transition from land to water. The stems can grow up to 2 meters long and protrude a few decimetres above the water. Red stem grows particularly well in shallow, warm and nutrient-rich waters. The plant usually roots in shallow riparian zones, but free-floating stems without roots can also survive in nutrient-rich deep water. Red stem is originally from South America.

Myriophyllum was imported for trade in pond and aquarium plants. The plants come into nature because people throw away excess plants in public waters, after which they can spread further.

Tuesday, 21 July 2020

A better image for your stereo microscope

In compound microscopes, an illumination parallel to the optical axis is the standard. A lot of hardware is implemented to ensure this axial illumination: Center-adjustable Field and Aperture diaphragm, centerable light rings for Phase contrast and Darkfield for transmitted light, center-adjustable objectives and/or centerable rotatable stages in Polarization microscopes. With all these microscopes we are working on 2-dimensional samples.

In stereo microscopy, a 3D image from a 3-dimensional sample is our ambition. Different viewing angles for both eyes create different images on the retina of the left and the right eye. Our brain is going to process both images. This concept is best comprehensible in the Greenough construction of a traditional stereo microscope: two complete separate beam paths from objective to the eyes, mounted in a relative angle of 11°-16°. But even in the modern, more flexible CMO (Central Main Objective) concept a different viewing angle is realized.

Greenough type                       CMO (Galilean) type 

Thursday, 16 July 2020

Desmids - Beautiful single celled algae

There are many different types of algae, differing in both size, shape, color, habitat and more. Some types are multicellular and very large like seaweed, some are microscopic and colonial like Eudorina, while others consist of only a single cell. Some of these are called desmids (desmidiales).

Desmids are highly symmetrical unicellular green algae which can take on many different shapes depending on the specific species. The desmids also vary in size between species, the smallest being only a couple of microns and the largest reaching a size of several hundreds of microns and are visible with the naked eye. Desmids are most commonly found in freshwater where several thousand species can be found.

Wednesday, 8 July 2020

Protected against harsh conditions

As mentioned in a previous publication, helm grass is what we encounter in the dunes among others in the Netherlands. The Ammophillia arenaria can withstand the salty water and salty sea air. Ammophillia arenaria can be planted on all types of soil, only on clay soil it is best to make the soil poor with masonry sand. The soil must be calcareous.

Wednesday, 1 July 2020

Red blood cells - the cells that help you breath

Adult humans carry around 5 liters of blood in their circulatory system. Roughly half of that is cells, and the other half is a pale yellow liquid called plasma. The vast majority of these cells are erythrocytes, more commonly known as red blood cells (RBCs). Our red blood cells are the most abundant cell type in the human body accounting for approximately 70% of all your cells. They measure roughly 7 microns in diameter and around 1-2 microns in thickness.

Tuesday, 23 June 2020

Sambucus, breathing through the cork layer

Cork is formed by a cambium layer that itself almost always arises as secondary meristem from the collenchyma or parenchyma layer directly under the epidermis. Unlike sclerenchymal cells, collenchymal cells are still alive and have retained the ability to differentiate. Cork cambium cells only divide periclinally, creating the typical rows of daughter cells. In this way mainly cork cells are produced to the outside and to a much lesser extent (sometimes not at all) cork parenchyma is produced to the inside. Cork cambium, cork cells and cork parenchyma together are also called periderm. Developed cork cells are dead and their cell walls contain suberine, a greasy substance that repels water.