Background Basics:
Units of measure
Hydrophobic molecules
Proteins
Compound molecules
pH
DNA and RNA
Key Concepts
Functional
compartments of the body
Biological membranes
Intracellular
compartments
Tissue types
Tissue remodeling
Organs
Study of cell structure
= ?
Study of tissue
structure = ?
Study of how cells work
= ?
Functional Body
Compartments
• Various membrane lined body cavities
• Lumens of hollow organs are NOT part of internal environment
• Body has 3 fluid compartments
Fig 3-1
Fig 3-2
Membrane –2 Meanings!
• Epithelial membranes
vs.
• Cell membranes and
Membranes around organelles
Functions of Cell Membranes
1. Physical isolation
2. Regulation of exchange with environment
3. Communication between cell and environment
4. Structural support
Cell Membrane Structure: Fluid Mosaic Model
Thickness ~ 8nm
PLs, Sphingolipids and
Cholesterol
Proteins: peripheral (associated) or integral (transmembrane)
Fig 3-4
Phospholipid Behavior in H2O:
• Phospholipid bilayer
• Micelle– Role in digestion and
absorption of fats in GI tract
• Liposome– Larger, bilayer,
hollow center with aqueous core
Clinical relevance?
Cell Anatomy &
Intracellular
Compartments
ECF
Cellmembrane
Membranousorganelles
Non-membranous
organelles
The Cell
Fig 3-11
Cell differentiation
Mechanism: differential gene activation
From 1 zygote to 200 different types of cells
Cytoplasm
Cytosol:
= semigelatinous
intracellular fluid
Medium for suspension of
1. Organelles,
2. Ions, nutrients, wastes,
enzymes etc.…….
3. Inclusions
Organelles perform
specialized tasks.
Membranous
organelles
Non-membranous
Organelles
(Inclusions)
Cytoskeleton
Functions in
• Cell shape
• Internal organization
• Transport
• Cell to cell links (
tissues)
• Movement
Made of protein fibers1. Microfilaments (actin)
2. Intermediate filaments
(myosin, keratin)
3. Microtubules
Fig 3-14
Microtubules form Centrosomes and
Centrioles
1 centrosome contains 2 centriolesCentrosomes organize microtubules
Centrioles: bundles of microtubules
Pull chromosomes, form core in cilia
Special Structural Features of Cell
Membranes and Cytoskeletons
• Microvilli
• Cilia
• Stereocilia
• Flagella
Function?
1. Myosins (see Ch12)
2. Kinesins (movement along microtubules)
3. Dyneins (cilia and flagella movement)
Motor Proteins Create Movement
Compare to Fig 3-15
• Function: ?
• Fixed to ER or free in cytoplasm
Ribosomes
Membranous Organelles
Special compartments for special functions
– Separate harmful substances from other cell areas
– Separate function from other cell areas
__________on/-a
cell’s powerhouse.
Has own DNA
RER & SER
____________ synthesis,
storage, modification &
transport vesicle formation
Synthesis and conversion of FA,
steroids, lipids
In muscle: ______________
Golgi Complex
• Modification (labeling) of proteins
• Packaging into secretory (to ECF) or storage
vesicles
TEM
“Post office” of cell
Protein
Secretion
Cytoplasmic Vesicles: Lysosomes
Digestion (~ 50 enzymes) of bacteria and old organelles
Enzymes only active at pH of 100 – 1,000 x < cytoplasm
pH = ?Also dissolves Ca-carbonate of bone
Rheumatoid arthritis and
Tay-Sachs disease
Tay Sachs
Disease
(TSD)
Increased resistance to TB?
Peroxi-
somes
Major function: Degradation of long chain FAs
Generate hydrogen peroxide contain catalase
ALD
Smaller than Lysosomes -Different set of enzymes
Nucleus
• Control Center
• Nuclear envelope with
nuclear pore complexes
for diffusion and active
transport
• Chromatin (DNA and
proteins)
• One or more nucleoli
• Genes
Tissues: Cell to Cell Junctions
• Electrical synapses
• Cylindrical proteins
(connexins) form
channels
• Can open and close
• Rapid transfer of
signals in cardiac &
smooth muscle
Gap Junctions
Tight Junctions• Complete barrier
(brick wall)
• Fusion of adjacent cell membranes via claudin and occludin
• Found in
–
–
Tight vs. leaky
epithelium
Anchoring Junctions
• Cell to cell or cell to matrix
• Anchoring junctions (CAMs: cadherins)– Desmosomes
– Adherens junctions
• Cell matrix attachments (CAMs: integrins)– Hemidesmosomes
– Spot desmosomes or focal adhesions
In cancer: Loss of
desmosomes
consequence?
Histology• Structure and function of all basic tissue
types: remember from Anatomy or review on
your own (starting p.72 with epithelia)
• Review concept of stem cells (totipotent –
pluripotent – multipotent – unipotent or
progenitor cell)
• Definition of organ?
Example: skin, see textbook p.83
Tissue
Remodeling
Tissue remodeling throughout a persons life
• Apoptosis = Programmed cell death (suicide)
Cell breaks up into membrane bound blebs which will be phagocytosed by other cells.
• Necrosis = traumatic cell death
Lack of O2, trauma, toxins
Cells rupture tissue damage & inflammation
Running Problem: The Pap Smear
Page 51 on
Cervical cells. Uniform in size and shape
normal
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