chapter
1
The Cell: Basic Structure and Function
Magnus von Knebel Doeberitz and Nicolas Wentzensen
Contents
P A R T I: B A S IC S T R U C T U R E A N D F U N C T IO N O F M A M M A LIA N C E L L S
C e ll M e m b ra n e , R e c e p to rs, a n d S ig n a l T ra n s d u c tio n
O v e rv ie w
C e ll Ju n c t io n s
N u c le u s
C e ll G ro w th a n d D iv isio n
C o n t e n ts o f t h e N u c le u s
P A R T II: T H E M O L E C U L A R B A S IS O F N E O P L A S IA
N u c le a r M o r p h o lo g y
H e m a t o x y lin
O v e rv ie w
N u c le o li
P rin c ip le s o f M a lig n a n t T ra n s fo rm a tio n
N u c le a r E n v e lo p e a n d N u c le a r S h a p e
C a n c e r-re la te d G e n e s
C y to p la s m a n d P la sm a le m m a
C y to p la s m ic S ta in
T h e M a jo r P a th w a y s o f C a r c in o g e n e s is
E n d o p la s m ic R e tic u lu m
C a r c in o g e n e s is in d u c e d b y P a p illo m a v iru s In fe c tio n s
G o lg i A p p a ra tu s
B asic S t r u c t u r e o f t h e V iru s a n d Its G e n o m e
M ito ch o n d ria
E p id e m io lo g y o f H p V In fe c tio n s
T h e R o le o f t h e H R -H p V E 6 a n d E 7 G e n e s
L y so so m e s
p ro g re s s io n o f H p V - In fe c te d e p ith e lia l C e lls t o In v a s iv e C a n c e r C e lls
C y to s k e le to n , C e n tro s o m e
C o n c lu d in g R e m a rk s
PART I: BASIC STRUCTURE AND FUNCTION OF MAMMALIAN CELLS
Overview
Cells are the basic structural and functional units of all liv-
ing organisms. The estimations about the total cell count of a
human body vary widely; a number as large as 1014 seems con-
ceivable. Although the principal components of all cells are very
similar, the differentiation of cells results in a wide variation of
cellular morphology and function.
The smallest human cells by diameter are spermatozoa
with a size of ~3 pm, followed by the anucleate erythrocytes
(8 pm). The largest cells are female oocytes that can be as large
as 35-40 pm and are visible to the naked eye. Motor neurons are
extremely long cells, with their axons reaching from the spine to
the distal extremities (up to 1.4 m length).
Most cells can only be functional in large united structures,
such as organs or suborganic structures. Other cells, mainly
of hemato- or lymphopoietic origin, are mobile and active
as single cells, although in many cases, their functionality is
dependent on interaction with other cells.
Cytopathology studies diseases on the cellular level. While in
histopathology, cells are assessed in the spatial context, in vir-
tually all cytological applications, they are removed from their
spatial context and must be assessed isolated or as cell sheets.
Apart from the loss of the spatial information, cells can have
considerably altered morphology when taken out of the united
structures. Cell-cell contacts are important features that build
the shape of a cell. Many structural elements within a cell are
connected to proteins that are attached to other cells or the
basal membrane. This must be taken into account when cells
are compared in histological and cytological assessments.
Another important difference between histology and cytol-
ogy is based on the fact that in histology, plain two-dimensional
tissue sections are assessed, while in most cytology applications,
complete cells that still have some three-dimensional features,
although they might appear flat in the microscope, are analyzed.
Based on these facts, the transfer of histological morphology to
the picture seen in cytology is limited.
In this section, an overview of the most important cellular
structures and functions relevant for cytopathology are pre-
sented (Fig. 1.1). We have assembled the most important infor-
mation on cellular structures by describing the regular function
in brief, the relevance for cytopathology, and the morphology
in normal and abnormal cells. For more detailed information
about cellular structures and functions, a cell biology textbook
is recommended.
3
previous page 9 ComprehensiveCytopathology 1104p 2008 read online next page 11 ComprehensiveCytopathology 1104p 2008 read online Home Toggle text on/off