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Biology 1110 Principles of Biology Biology 1110 Laboratory Laboratory # 2 Beginning Histology Vascular Tissue Support/Review Materials All of the micrographs in this presentation were photographed in the MnWest Biology laboratory unless otherwise noted. The microscope symbol that you see indicates a change in microscope power. A left mouse click on the microscope most often increases the viewing magnification. Give it a try.

Histology –the study of tissues. A tissue is an association of similar cells united in structure and function. The major animal tissue groups include: Epithelial Connective – this includes the vascular tissue, studied in this presentation. 3. Muscle 4. Nervous

Vascular tissue – general information All blood, regardless of source, contains two categories of blood cells. They are: Erythrocytes (which means red cells), or red blood cells (RBCs). These are always the most abundant blood cell, and perform the important function of oxygen transport. Leukocytes, or white blood cells (WBCs). There are a number of different types of leukocytes. They all help to defend the body and prevent disease.

Vascular tissue – general information In addition to erythrocytes (RBCs) and leukocytes (WBCs), human blood contains small cell fragments called platelets. We will cover platelet function later. All of the blood cells and the platelets together are said to make up the formed elements. About 45% of your blood is formed elements. The remaining 55% of you blood is the straw-colored, liquid portion called plasma. The plasma contains many important things including water, electrolytes, nutrients, numerous proteins, wastes, hormones, some respiratory gases, and buffers.

Vascular tissue – general information If you centrifuge (spin) a sample of your blood, it quickly separates into the components previously discussed and demonstrated on this slide. 55% Plasma Leukocytes (WBCs) & platelets The formed elements – 45% of the blood sample. Erythrocytes (RBCs)

Vascular tissue - A circulating tissue made up of a number of different cell types. In this lab we will briefly study the vascular tissue of an amphbian (frog) before emphasizing mammalian (human) blood. Amphibian Blood Human Blood

Amphibian Blood In this stained sample of amphibian blood we can see the many erythrocytes (RBCs). These RBCs have a nucleus, and they are the largest of the blood cells. The micrograph also demonstrates a number of leukocytes (WBCs). Take a look on a higher power.

A WBC called a heterophil Abundant erythrocytes (RBCs) A WBC called a heterophil A thrombocyte – another type of WBC

Amphibian Blood This amphibian blood smear contains the expected, high number of erythrocytes (RBCs). Can you spot and identify the leukocytes (WBCs)?

Thrombocyte Thrombocyte Heterophil

Amphibian Blood Take a closer look This micrograph of amphibian blood demonstrates a number of different blood cells. We can identify erythocytes (RBCs), a heterophil, a lymphocyte, and three thrombocytes. Remember that the leukocytes (WBCs) are helping, in some way, to protect the animal. Note the three thrombocytes that appear to be sticking to each other. This gives us a suggestion regarding their function. Take a closer look

The Function of Amphibian Thrombocytes These “football-shaped” and “sticky” cells are protective in that they are necessary for the formation of blood clots.

These two micrographs demonstrate all of the amphibian blood cells that you are responsible for. If you cannot identify all cells, please return and review the previous slides.

Human Blood Cell types, number, and function Erythrocytes (RBCs) dominate the formed elements. In a normal sample of human blood there would be about 5 million RBC/mm3 For every single leukocyte (WBC), there are 750-1000 erythrocytes (RBCs). Erythrocytes (RBCs) are produced in your red bone marrow at a rate of well over two million per second. Why do you need so many RBCs? What do they do? Plasma 55% Leukocytes (WBCs) & platelets Erythrocytes (RBCs)

Human Blood This smear of human blood has been stained and appears typical. The great majority of blood cells are erythrocytes (RBCs). Remember that your RBCs outnumber your WBCs around 750-1000 to 1. You need this great number of RBCs to transport oxygen to all of your living cells. Like most creatures, we are aerobic (oxygen-requiring).

Human Blood Cell types, number, and function Mammalian RBCs, are the smallest of all blood cells. They are biconcave, and thus very thin in the middle. This is demonstrated nicely in this micrograph. Lets take a close look.

Human Blood Cell types, number, and function Notice the light, central area of the RBCs in this micrograph. They are thin in the middle so more light passes through. The RBCs are also anucleate (without a nucleus). That is why they stain lighter than the WBCs. RBCs are flexible “bags” filled with millions of hemoglobin molecules. It is hemoglobin that attaches to the oxygen for transport.

Human Blood Cell types, number, and function The two human blood smears appear somewhat different due to different staining techniques. They both, however, nicely demonstrate larger, nucleated, leukocytes (WBCs). The nuclear material of these WBCs has a great attraction for the biological stain applied. A quick look at these micrographs reveals leukocytes (WBCs) of different kinds. Regardless of kind, they all play an important role in your bodies protective system. Leukocytes fight certain microorganisms and help prevent disease.

Human Blood Cell types, number, and function Leukocytes (WBCs) in human blood. Neutrophils Lymphocytes Monocytes Eosinophils Basophils Platelets – these are cell fragments. Plasma 55% Leukocytes (WBCs) & platelets Erythrocytes (RBCs)

Human Blood Cell types, number, and function Leukocyte (WBC) types and %. Neutrophils 50 – 70 % Eosinophils 1 – 3 % Basophils 0.4 – 1 % Lymphocytes 25 – 35 % Monocytes 4 – 6 % Leukocytes (WBCs) & platelets

Human Blood Cell types, number, and function Leukocytes (WBCs) are classified into two main groups. Neutrophils, eosinophils, and basophils are granulocytes. These cells have granules in their cytoplasm. The remaining two WBCs, lymphocytes and monocytes are agranulocytes. These cells lack the cyoplasmic granules. Eosinophil lymphocyte monocyte neutrophil

Human Blood Smear This stained sample of human blood demonstrates a number of the formed elements. We recognize the many erythrocytes (RBCs) as well as a number of small, darkly stained platelets. Increase the magnification and focus in on the large, centrally located blood cell.

Human Blood Smear This high power microscopic view demonstrates a human neutrophil. The single nucleus has multiple lobes. This particular neutrophil, with its many nuclear lobes is sometines called a hypersegmented neutrophil. Neutrophils are your most abundant white blood cells.

A single, mature eosinophil is demonstrated in this micrograph. Human Blood Smear A single, mature eosinophil is demonstrated in this micrograph. These WBCs make up only about 1-3% of your total WBC number. Take a look on higher magnification.

Human Blood Smear When stained, eosinophils usually take on a distivtive coloration. Note the very granular cytoplasm and remember they are classed as granulocytes. A mature eosinophil will have two distinct lobes making up the nucleus.

Human Blood Smear In addition to the many erythrocytes (RBCs), this micrograph nicely demonstrates two leukocytes (WBCs). These two WBCs are classed as granulocytes and should be easily recognizable. If you are having problems identifying these WBCs, please review the previous slides.

Human Blood Smear Both micrographs below demonstrate a single monocyte. These large white blood cells (leukocytes) have a single nucleus that seems to often resemble the letter C. Monocytes normally make up about 4-6% of your WBCs. They are very important in fighting infection and preventing disease.

Human Blood Smear In this micrograph we again recognize the many red blood cells (erythrocytes). As we finish our study of white blood cells (leukocytes) we focus on the two very similar, and deeply stained cells. These two WBCs are lymphocytes.

Human Blood Smear Below you will see the same blood smear at different magnifications. Note the lymphocyte at the pointer. These abundant WBCs play very important protective roles in your bodies immune system. Note that these small, WBCs have a very large nucleus and little cytoplasm. They make up 25-35% of your WBCs.

Human Blood Smear A close look at the human blood samples below reveals small, dark stained “specks” visible among the blood cells. Some of these are identified with a pointer. These are cell fragments known as platelets. Platelets play a number of roles in the process of hemostasis. Hemostasis is the cessation of bleeding ( blood clotting).

Matching Exercise – the formed elements of blood Matching Exercise – the formed elements of blood. Identify the correct matches. When complete, push the down arrow to check your answers. Eosinophil Monocyte Lymphocyte Neutrophil Erythrocytes (RBCs) RBCs with scattered platelets

The End

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