Transcript A Liver Cell - frozencrocus.com

EXERCISE PHYSIOLOGY
Movement (kinesiology):
anatomy . physiology .
biochemistry . physics
Control of the bioenergetics of
movement:
biochemistry . enzymology
molecular biology
Control of movement:
motor control .
anatomy .
neurophysiology
Enhancement of performance:
molecular biology . cell
biology . signal transduction
physics . motor control
Bioenergetics of movement:
biochemistry .
endocrinology
Movement and health:
nutrition . biochemistry
molecular biology . cell
biology . immunology .
endocrinology . oncology .
pathophysiology . toxicology
To deal with all this stuff we need a cellular view of the world
Cells & Stuff
ATP provides energy to build and repair cell structures
and membranes. We consume oxygen when the molecules
in the food are metabolized to CO2 and H2O and the energy
from this process is used to synthesize ATP.
Membranes which surround cells and organelles
are very sensitive to physical trauma and chemical
attack
Typical Cell Membrane
Cell membranes allow the outside to
be different from the inside
Ca+
+
Ca
A Liver Cell
Microtrabecular Lattice
aka: Cytoskeleton
Heart Cells
Kidney Cells
Testes Cells
Organs
Cells with the same function are organized as organs: kidney,
adrenal, liver, etc.
Organs with supporting functions are organized as organ
systems: cardiovascular system (heart, veins, arteries),
endocrine system (pituitary, hypothalmus, adrenal, pancreas
…), etc.
Liver Following Different Treatments
Liver from
Sedentary-Ethanol
Liver from
Control
Liver from
Run-Ethanol
Nucleus
Stores and transmits genetic information in the
form of DNA. Genetic information (as
messenger RNA) can pass from nucleus into
cytoplasm, where amino acids are assembled
into proteins
mRNA
Sequence of DNA molecules codes for a sequence of amino acids of a protein.
Different sequences of DNA molecules (genes) code for different proteins.
Transcription of DNA sequence into mRNA sequence is tightly controlled by
transcription activators and repressors which are in turn controlled by metabolic,
hormonal, of other signaling processes.
Endoplasmic
reticulum
Extensive membranous
network of tubules and
flattened sheets
Granular ER has
ribosomes attached,
which are the sites of
protein synthesis
Smooth ER stores and
releases calcium
Granular ER
Smooth ER
Golgi apparatus
Series of cup-shaped,
flattened membranous sacs
associated with numerous
vesicles
Function is to concentrate,
modify and sort newly
synthesised proteins prior
to secretion from the cell
Mitochondrion
Krebs’ cycle
-oxidation of
Large surface area
Selective permeability
fatty acids
Electron transport chain
1 m
Active Transport & Life
• Energy for active transport which maintains
cellular integrity comes mainly from
mitochondria …
• If mitochondrial function declines then total
cell function declines, possibly resulting in
cell death …
• If a sufficient number of cells die then organ
failure results … possibly leading to death
of the individual
Active Transport
Cells spend a tremendous amount of energy moving
compounds into the cell (or into the endoplasmic
reticulum) and other compounds out of the cell through
Active Transport
Active Transport of Sodium &
Potassium
This next set of slides is here to introduce the concept
that the reason we get changes with exercise is not to win
medals in athletic competition but rather to avoid the
toxic effects of exercise.
Membranes & Necrosis
Membranes which surround cells and organelles
are very sensitive to physical trauma, or to
chemical damage caused by oxygen radicals or
chemical radicals
An intact cell membrane acts as a barrier for
(among other things) charged particles such
as calcium.
A damaged cell membrane will allow (among
other things) charged particles to enter the cell
or organelle.
Membranes & Necrosis
Damage to cell membranes or to endoplasmic reticulum
membranes allows calcium (and other ions) to leak into
cell cytoplasm – increasing osmotic pressure and
causing swelling
Membranes & Necrosis
Increased membrane permeability leads to swelling of the
endoplasmic reticulum and more calcium leaks. Calcium
activates lysosomal enzymes which digest lipids leading to
more membrane leaks.
Membranes & Necrosis
Mitochondria take up calcium and greatly reduce ATP synthesis –
leading to poor repair of membranes and increased damage.
Mitochondria swell up while cellular membranes fragment and
lysosomal enzymes continue to digest cellular components
Membranes & Necrosis
When the cell membrane is damaged, or “dying”,
the cell synthesizes and releases cytokines which
initiate an inflammatory process