Anatomy 1

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The Cell
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Introduction to Cells

• The basic structural and functional unit of all
  living things
• Major cellular regions
• The plasma membrane
• The cytoplasm
• The nucleus

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• The Plasma membrane
• Structure
• Double layer (bilayer) of lipid
• molecules
• Phospholipid polar heads (hydrophilic) outward
• Fatty acid chains (hydrophobic) are tail to tail
• Protein molecules are dispersed within

Structure of a phospholipid
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The membrane structure is actually fluid, with
proteins moving around in it
Plasma membrane
extracellular
lipid bilayer
intracellular
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Functions of the plasma membrane

• Separates intracellular fluid from extracellular
  fluid
• Acts as a barrier
• Some membrane proteins act as receptors
• Determines which substances enter and leave cell
• Diffusion
• Specific transport mechanisms
• Bulk (vesicular) transport
• Exocytosis
• Endocytosis

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Phagocytosis (a type of endocytosis)
Receptor-mediated endocytosis
Exocytosis
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The Cytoplasm

• The Cytosol jelly-like fluid matrix
• Organelles (about nine types)
• Ribosomes sites of protein synthesis
• Endoplasmic reticulum (rough and smooth)
  products synthesized (protein, lipid, steroid)
  store calcium
• Golgi apparatus packages and modifies proteins
• Mitochondria synthesizes ATP (energy source)
• Lysosomes intracellular digestion
  (disintegrators)
• Peroxisomes detoxify substances
• Cytoskeleton supports cellular structures
• Centrosomes and centrioles organize microtubule
  network
• Inclusions not permanent (eg. food storage units
  and pigments)

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Endoplasmic reticulum
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Assembly of proteins at the rough endoplasmic
reticulum
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The Genetic Code Replication DNA making a
copy of itself Transcription making of RNA from
code of DNA Translation making of protein coded
by tRNA via mRNA via DNA (3 bases make one
protein)
DNA bases T, A, C, G (thymine, adenine,
cytosine, guanine) RNA bases U, A, C, G
(uracil instead of thymine) mRNA messenger
RNA tRNA transfer RNA rRNA - ribosomal RNA
                                                  
        .                               

                                  
http//biology.kenyon.edu/slonc/bio3/ribo/ribo1.ht
ml
For animation of translation
Elongation of the polypeptide chain begins by the
appropriate aminoacyl-tRNA binding to the codon
in the A site of the ribosome.
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Golgi apparatus
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Role of golgi apparatus in packaging products of
rough ER for use in the cell and for secretion
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Mitochondria
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Lysosomes
Peroxisomes like small lysosomes
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The cytoskeleton 3 types of rods (a)
microtubules (b) microfilaments (c)
intermediate filaments
Microtubules appear as green network surrounding
the cells blue nucleus
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Microfilament thinnest
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Intermediate filament the most permanent, like
guy wires
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Centrosomes and centrioles
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The Nucleus

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The nucleus

• Control center of the cell
• Surrounded by a nuclear envelope
• Nucleolus associated with ribosome production
• Chromatin - extended condensed
• DNA and histones (packaging material)
• Four types of nucleotides A, T, G, C
• Nucleosomes 8 histones wrapped in DNA
• Chromosomes

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NUCLEUS Control center of the cell Surrounded by
a nuclear envelope Nucleolus associated with
ribosome production Chromatin - extended
condensed
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CHROMATIN extended and condensed DNA and
histones (packaging material) Four types of
nucleotides A, T, G, C Nucleosomes 8 histones
wrapped in DNA Chromosomes
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The cell life cycle

• Interphase
• Variable time length
• Divided into G1, S (DNA replication) and G2
  subphases
• Mitosis division into two daughter cells
• Interphase
• Early prophase
• Late prophase
• Metaphase
• Anaphase
• Telophase and cytokinesis

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Cell life cycle
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Mitosis (the replicated DNA of the original cell
is parceled out into 2 new cells)
When chromosomes are ordered clinically, they are
usually in metaphase
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Cell diversity
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Developmental aspects

• Human life begins as a single cell
• From it, all the cells of the body will arise
• All cells have the same genes yet specialization
  indicates differential gene activation
• Cell differentiation the development of
  specific and distinctive features
• Aging
• Cellular
• Organismal

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Cancera malignant, invasive cellular tumor that
has the capacity of spreading throughout the body

• Neoplasm new growth AKA tumor
• Cells fail to honor normal controls of cell
  division
• Abnormal mass of proliferating cells
• Classified as
• Benign local growth
• Malignant - cancer (Latin for crab)
• Invades neighboring tissue
• Can metastasize spread
• Many gene mutations may be necessary for normal
  cells to transform

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Additional terms

• Dysplasia change in cell size, shape or
  arrangement can be due to irritation can be a
  precursor to cancer
• Hyperplasia increase in the number of cells
• Hypertrophy growth due to an increase in the
  size of the cells
• Apoptosis programmed cell death
• Necrosis death of cells or tissues because of
  disease or injury

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Compound Microscope
All optical microscopes share the same basic
components The ocular or eyepiece (1) to
bring the image into focus for the eye. The
eyepiece is inserted into the top end of the body
tube. Eyepieces are interchangeable and many
different eyepieces can be inserted with
different degrees of magnification. Typical
magnification values for eyepieces include 5x,
10x and 2x. Some eyepieces have a pointer. The
objectives (3) a cylinder containing one or
more lenses, typically made of glass, to collect
light from the sample. At the lower end of the
microscope tube one or more objective lenses are
screwed into a circular revolving nosepiece (2)
which may be rotated to select the required
objective lens. Typical magnification values of
objective lenses are 4x, 5x, 10x, 20x, 40x, 50x
and 100x. The stage (6) a platform below the
objective which supports the specimen being
viewed. In the center of the stage is a hole
through which light passes to illuminate the
specimen. The stage usually has arms to
hold slides (rectangular glass plates with
typical dimensions of 25 mm by 75 mm, on which
the specimen is mounted), the mechanical stage
(9) with a control knob (11.) The illumination
source below the stage, light is provided and
controlled in a variety of ways. At its simplest,
daylight is directed via a mirror. Most
microscopes, however, have their own controllable
light source (7) that is focused through an
optical device which concentrates it called
a condenser (8), with diaphragms (13)
controlling the amount of light let through and
filters available to manage the quality and
intensity of the light. The whole of the optical
assembly is attached to a rigid arm (10) which
in turn is attached to a base (12) to provide
the necessary rigidity. Mounted on the arm are
controls for focusing, typically a large wheel to
adjust coarse focus (4), together with a smaller
one to control fine focus (5).
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http//en.wikipedia.org/wiki/Optical_Microscope