Physiology course for pharmacy students, sheet#6
Dr.Loai Alzghoul
Atoms
organs
Cell physiology
molecular
cells
tissue
system
human body
Ex :
The temperature of the body is 37 if you
change your location to colder place
your temperature will become less than
37, receptors will detect the stimulus
then travel to the Center that gives order
to back to homeostasis.
Physiology: maintaining the
homeostasis
Homeostasis: keep the proper function.
Body must sense the variables
(stimulus) so that it can try to return to
equilibrium ( maintain the homeostasis)
Suppose that we have a deviation of
homeostasis ,What are the process
steps to return to homeostasis ?
 Detecting the stimulus(by
receptors)
 The stimulus transfer as a nerve
impulses or chemical signals to
the control center
 The control center (brain ) receive
the stimulus (input) and provide
output that travel again to the
response
 Response alters the controlled
condition
 When the response brings the
controlled, condition back to
normal
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Negative feedback
Ex. :Insulin is produced by the
pancreas cells
insulin function is to decrease the
amount of glucose in the body.
Body receptors detect the level of
glucose in the blood if it it in high level,
that means pancreas release high level
of insulin , so receptors will inhibit
pancreas cells from insulin production .
pancreas α cells produce glucagon that
increase the glucose of the blood
Physiology course for pharmacy students, sheet#6
Dr.Loai Alzghoul
When glucose
the receptors will
inhibit α cell from release glucagon.
This a negative feedback because the
result is inhibition.(high
stimulus=inhibition "inverse")
Ex.2:
Stomach produce acid for the digestive
process, if the stomach produce more
acid , the receptors detect that acid
produce in high level , then send
signals to inhibit acid production.
Cells consist of :
Nucleus , plasma membrane ,
mitocendria , cytosol ,Golgi complex ,
lysosome ,ER(smooth and rough)
,cytoskeleton , peroxisome .
positive feedback
most commonly with birth.
Oxytocin increase the movement of the
uterus muscles and then the receptors
sense the are movement and expansion
so send signals to increase the release
of oxytocin and so one.
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Physiology course for pharmacy students, sheet#6
Dr.Loai Alzghoul
-Lysosomes : digestion for useful
substances to reuse by endocytosis or
damage organs by autophage
-Peroxisomes: oxidizes toxic substance
such as alcohol and H2O2.
-What are the differences between
rough and smooth ER ?
rough contains ribosomes and produce
protein
smooth produce lipids and glucose
 Golgi : secretion . Sorting and
modification
What are lysosomes and peroxisomes
functions?
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Mitocendria : ATP production by
electrons transporters.
Cytoskeleton
 Support
 Anchoring organelles
Physiology course for pharmacy students, sheet#6
Dr.Loai Alzghoul
 Movement as cilia and flagella
 Transport
 Cell division
Functional proteins of plasma
membrane:






Ion channels (passive )
Transporter (active )
Receptors
Enzyme
Cell identity marker
Linker 1(link two cells together)
Cell membrane:
(Phospholipids bilayer)
Commonly transport by passive
movement from high conc. To low conc.
-Passive occurs spontaneously without
ATP
-Active needs ATP
plasma membrane : is selective ,
(allow certain substances to cross
membrane )
Ion channels: passive transport.
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intercellular Junctions :
Physiology course for pharmacy students, sheet#6
Dr.Loai Alzghoul
Gap junction connect the cytoplasm of
one cell with the other
The plasma membrane permeable to:
1.None polar (no charge)
2.Small molecules
Plasma membrane impermeable to
Polar substance
Charged substance
Dose the charge subsistent (ions ) polar
substances?
-Polar
Polar :partially charged , can cross
plasma membrane.
So sometimes we can call ions as polar
factors affecting permeability :
size , polarity ,lipid solubility and if there
are channels or transporters.
Co2 :small+polar = permeable
O2 : :small+polar = permeable
4 types of movement :
1.carrier mediate transport.
2.Facilliated diffusion.
3.Active transport
4.vesicular transport endocytosis.
(Endocytosis, Phagocytosis,
Exocytosis)
Which move first ??
There are four types of movement
Diffusion
Factors effecting diffusing
1. Distance( inverse relationship)
2. Size (inverse relationship)
3. Temperature :if the temperature is
high that will increase the rate of
diffusion (direct relationship)
4. Size of chemical gradient
(different in concentration )
5 electrical gradients
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Na+
100 gm
Glucose
100 gm
Na+
0
glucose
0
Plasma membrane
They have the same distance , temp.,
chemicals ingredient (100-0 )
But Na+ is smaller than glucose so
Na+ move faster.
Physiology course for pharmacy students, sheet#6
Dr.Loai Alzghoul
Ex.2 :
100 Na+
20 Na+
100 cl-
They have same distance , size and
temp.
but Na+ :
Chemical gradient is 100-20 = 80
Electrical gradient is 80-20= 60
Cl- :
Chemical gradient is 100-0=100
Electrical gradient is 100+20= 120
So Cl- will move faster .
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Done by : Sara Alhabees