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Pathophysiology
The word patho is derived from Greek word Pathos which means suffering and logos
means disclosure or more commonly system of formal study and physio means function
of organism.
Definition of pathophysiology:
It is the systemic study of functional changes in the cell, tissues, and organs altered by the
diseases and or injury.
Cells are divided in to two classes:
Prokaryotes
Eukaryotes
Prokaryotes are unicellular organisms,
found in all environments. Prokaryotes
are the largest group of organisms,
mostly due to the vast array of bacteria
which comprise the bulk of the
prokaryote classification.
Characteristics:
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No nuclear membrane (genetic
material dispersed throughout
cytoplasm)
No membrane-bound organelles
Simple internal structure
Most primitive type of cell
(appeared about four billion years
ago)
Carry genetic information in a
single circular chromosome.
Examples:
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Staphylococcus
Escherichia coli (E. coli)
Streptococcus
Cyanobacteria (blue green algae)
Rickettsiae
Eukaryotes are generally more
advanced than prokaryotes. There
are many unicellular organisms
which are eukaryotic, but all cells
in multicellular organisms are
eukaryotic.
Characteristics:
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Nuclear membrane
surrounding genetic
material
Numerous membranebound organelles
Complex internal
structure
Has several chromosomes
Appeared approximately
one billion years ago
Examples:
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Paramecium
Dinoflagellates
sapiens
Plants
Animals
Fungi
Algae
It is hypothesized that a primitive
bacterium once surrounded its
food after releasing its digestive
enzymes. The membrane folded
inward and pinched off, creating
the first digestive membranebound organelle.
Cellular functions:
Movement: Muscle cells
Conductivity: Nerve cells
Metabolic absorption: Intestine and kidney cells
Secretion: Mucosal glands, adrenals, testis, and ovary.
Excretion: Lysosomes
Respiration: Mitochondria
Reproduction: Nerve cells cannot reproduce
Communication: Pancreatic cells
Eukaryotic cell
Have three components
Plasma membrane/ plasma lemma
Cytoplasm
Organs
Organs:
Organelles
Nucleus:
Present at the center of the cell. Is a largest
membrane bound organelle. It contains
nucleolus.
Nucleolus contains:
RNA
DNA
DNA binding protein
Histones
Ribosome:
Is RNA protein complex (nucleoproteins).
Synthesized in nucleolus and secreted into
the cytoplasm through the pores in the
nuclear envelop.
Function
Cell division
Control of genetic information
Replication and repair of DNA
Transcription of information stored in the
DNA
Endoplasmic reticulum:
Endo: within
Plasma: cytoplasm
Reticulum: network
Synthesis and transport of protein and lipid
components of most of cell’s organelles.
Rough endoplasmic reticulum:
Due to the presence of ribosomes and
ribonucleoprotien particles
Synthesizes proteins that are used to
construct membranes of other organelles
and or of the cell itself.
Smooth endoplasmic reticulum:
Does not have ribosomes on the surface
Communicates with the Golgi complex.
Interacts with other organelles particularly
To provide sites for cellular protein
synthesis
Lysosomes and Peroxisomes.
Has enzymes involved in the synthesis of
steroid hormones and are responsible for
variety of reactions required to remove
toxic substances from the cell.
Golgi complex ( Golgi apparatus):
Is a network of flattened smooth
membranes and vesicles located near the
nucleus.
Is a refining plant and directs traffic in the
cell.
Lysosomes:
Lyso : dissolution
Soma: body
Originate from golgi complex.
Contains digestive enzymes called
hydrolases.
Active by maintaining low internal pH.
Digestion of
Cellular nutrients
Intracellular debris( when the cell
completes its life span and dies the
lysosomes digest the cell the process is
called auto digestion and the involved
lysosome is called autolysosome or
autophagosome.),
Potentially harmful extra cellular
substances.
Defects in lysosomes can cause:
Pompe disease
Tay- Sachs disease
Gout
Peroxisomes( micro bodies):
Similar to lysosomes in appearance but are
larger and oval or irregular in shape.
Contains oxidative enzymes.
Mitochondria:
The enzymes use oxygen to remove
hydrogen atoms from specific substrates in
an oxidative reaction.
Synthesis of specialized phospholipids
necessary fro nerve cell myelination.
Cellular energy metabolism
Mito: thread
Chondros: granule
Appear as spheres, rods, or filamentous
bodies.
Vaults:
Are cytoplasmic ribonucleoprotiens larger
than ribosomes.
Shape is like octagonal barrel.
Cellular trucks
Cytosol:
Is gelatinous semi liquid portion of the cytoplasm accounts for about 55% of the total cell
volume.
Functions:
Intermediary metabolism
Ribosomal protein synthesis
Storage of carbohydrates, fat, and secretory vesicles
Cytoskeleton:
Composed of network of protein filaments
The most important ones are
Microtubules
Are small hollow, cylindrical, unbrached tubules made of protein.
Function:
Add strength to the cells structure
Support and move organelles
Facilitate the transport of impulse along nerve cells
Has role in inflammatory and immune response and hormonal secretion
Involved in the external movement or motility of the cell
Involved in cell division called centrioles
Actin filaments or microfilaments
Are smaller and occur in bundles
Function:
Cellular locomotion
Maintenance of cell and tissue shape
Regulate cell growth.
Plasma membrane:
Surround a cell or enclose an intracellular organelle.
Functions:
Protection
Transport
Cell to cell recognition
Cellular motility
Maintaining cellular shape
Membrane composition:
The major chemical components of all membranes are
Lipids
Proteins
Intracellular membranes have higher percentage of proteins than the plasma membrane.
Lipids:
Basic component is a bilayer of lipid molecules- phospholipids (70%)
Glycolipids (5%)
Cholesterol (25%)
Lipid molecules are polar or amphipathic (one part is hydrophobic the other part is
hydrophilic).
Functions:
Is responsible for structural integrity
Impermeable to most of the water soluble molecules
Serves barrier to diffusion of water and hydrophilic substances
Proteins:
Two classifications
Peripheral: not embedded in the bilayer but reside at one surface or other, or bound to an
integral protein.
Integral: embedded in the lipid bilayer
Membrane structure is determined by the lipid bilayer but the membrane functions are
determined by the proteins.
Cellular receptors:
Are protein molecules on the plasma membrane, in the cytoplasm, or in the nucleus that
is capable of recognizing and binding with specific smaller molecules are called ligands.
Receptors are classified on the basis of their
Location
Function
Cell to cell adhesions:
Cells are held together by
Extra cellular matrix:
Is mesh work of fibrous proteins embedded in the watery gel like substance composed of
complex carbohydrates.
http://web.indstate.edu/thcme/mwking/extracellularmatrix.html
Cell adhesion molecules in the cells plasma membrane
Specialized cell junctions:
The three main types of junctions are
Desmosomes
Tight junctions
Gap junctions
http://www.biology.arizona.edu/cell_bio/problem_sets/membranes/13q.html
http://www.esf.edu/efb/course/efb325/lectures/junctions.htm
Cellular communication and signal transduction:
Communicate in three ways
From a protein channels that directly coordinate the activities of the adjacent cells
Display plasma membrane bound signaling molecules
Secrete chemicals
Membrane transport:
Is mainly by
Passive transport
Active transport
Passive transport:
Diffusion
Filtration
Osmosis
http://www.mun.ca/biology/Osmosis_Diffusion/tutor2.html
http://www.bbc.co.uk/education/asguru/biology/01cellbiology/05pathways/06passivesim
ple/index.shtml
Cellular reproduction:
Meiosis
Mitosis
Mitosis:
The reproduction or division of other body cells.
http://www.cellsalive.com/mitosis.htm
http://micro.magnet.fsu.edu/micro/gallery/mitosis/mitosis.html
Tissues:
Body is made up of four levels of organization, they are
Cells
Tissues
Organs
Systems
Tissues:
Cells of common structure and function are organized in to tissues.
Types:
Muscle
Neural
Epithelial
Connective
Muscle
Composed of myocytes
http://www.botany.uwc.ac.za/sci_ed/grade10/mammal/muscle.htm
Neural:
http://www.botany.uwc.ac.za/sci_ed/grade10/mammal/nervous.htm
Epithelial:
Covers most of the internal and external surfaces of the body
http://www.botany.uwc.ac.za/sci_ed/grade10/mammal/Epithelial.htm
Connective:
The three types of fibers produced are
Collagenous (white)
Elastic(yellow)
Reticular
http://biology.about.com/gi/dynamic/offsite.htm?site=http://www.lab.anhb.uwa.edu.au/m
b140/CorePages/Connective/Connect.htm%23labelastic
Cellular adaptation:
The most significant adaptive changes are
Atrophy:
Is decrease or shrinkage in the cell size.
Classified as
Physiologic: Occurs during early development.
Pathologic
Hypertrophy:
Increase in the size of cell and consequently in the size of affected organ.
Hyperplasia:
Increase in the number of cells resulting from an increased rate of cell division.
Metaplasia:
Irreversible replacement of one mature cell by another sometimes less differentiated cell
type
Cellular injury:
Three common forms of cell injury are
Hypoxic injury
Reactive oxygen species and free radical induced injury
Chemical injury
http://medinfo.ufl.edu/pa/chuck/fall/handouts/injury.htm
Here are some questionnaires:
http://www.funtrivia.com/quizzes/sci__tech/biology/cell_and_molecular_biology.html
http://www.cellsalive.com/quiz1.htm
http://www.sp.uconn.edu/~virtclas/cgibin/quiz/quiz.cgi?/u/pi264vc/public_html/cellquiz.qz
http://www.cellsalive.com/toc.htm
http://www.bgsu.edu/departments/chem/midden/MITBCT/cb/sq.html
http://www.funtrivia.com/playquiz/quiz93971ac45f0.html
http://www.biologycorner.com/bio3/quiz_cell.html
http://www.georgetown.edu/dml/educ/pathlab_manual/quiz/quiz_ci.htm
http://www-medlib.med.utah.edu/WebPath/EXAM/MULTGEN/cellfrm.html
http://www.sciencepages.co.uk/keystage5/ASA2Biology/CellBiolQuestions.php
http://biog-101-104.bio.cornell.edu/biog101_104/tutorials/cell_division.html
References: