Transcript PowerPoint - Bryn Mawr School Faculty Web Pages

The above picture is a smear of
human peripheral blood. The
numerous small reddish cells
seen here are erythrocytes (each
about 7 µm across, they are by far
the most numerous type of blood
cell).
Blood is a connective tissue
consisting of cells suspended
in an intercellular fluid (the
blood plasma).
Blood functions to transport
oxygen, carbon dioxide,
nutrients, wastes, hormones,
etc. to and from the body's
cells.
Blood cells consist three types:
1. erythrocytes (red blood cells)
2. leukocytes (white blood cells)
3. thrombocytes (platelets).
Blood is made up of red blood cells, white blood cells, platelets, and plasma.
RED BLOOD CELLS
Note that RBC’s in
mammals do not have a
nucleus when mature,
which was lost during
maturation in the bone
marrow. Erythrocytes (red
blood cells) have a reddish
color (and, thus so does
your blood) due to their
high content of the iron protein complex called
hemoglobin. Hemoglobin
is the molecule that allows
erythrocytes to bind
oxygen and carry it
throughout the body.
RED BLOOD CELLS
Red blood cells as well as most (but not all)
and platelets, are made in the bone marrow.
The normal lifespan of RBCs in the
circulation is only about 120 days. Worn
out RBCs are removed by the spleen and
liver where hemoglobin is recycled.
A high RBC level, a condition called
“erythrocytosis,” can be caused by
smoking, living at high altitudes, or by
disease.
Low red blood cell levels, a condition called
“anemia,” can be due to a loss of blood,
loss of iron, a vitamin deficiency, or other
disease conditions.
White Blood Cells
(Leukocytes)
•Larger than RBCs
•Have nuclei
•Far less numerous
than RBCs
Three types of
Leukocytes:
This is an actual picture of White Blood Cells, in with
some red blood cells. The platelets are stained
purple, a T-Lymphocyte white cell is stained green,
and a Monocyte white cell is stained gold as seen
through a scanning electron microscope.
1. Granulocytes
2. Monocytes
3. Lymphocytes (B and T
cells)
WHITE BLOOD CELLS
Macrophages are one of many types of white blood cells (leukocytes) present in
body tissues. Macrophages are important in immune response and cell stability
because they mobilize in cell tissue to attack large foreign particles such as
bacteria, yeast, and dead cells. Macrophages are derived from precursor cells
called monocytes that first develop in bone marrow. Monocytes enter the blood
and travel throughout the body in the circulatory system. When needed, circulatory
monocytes move into tissue, where they become macrophages. Here a lung
(alveolar) macrophage is seeking foreign bacteria (Escherichia coli) with
specialized cell extensions called filopodia. Macrophages engulf and digest foreign
materials in a process known as phagocytosis.
Platelets!
Cell fragements that play an important role
in clotting.
The platelets collect at the site of injury and
release fibrin. Fibrin is a protein known as
the “clotting factor.” It produces a network
that traps cells and this forms a clot.