Physiology introduction

1. Done by: Abdelhadi Okasha

2. Topics discussed in this lecture
1- Structure of the body
- Body → Systems → Organs → tissues
→ cells
- Cells achieve various functions
2- closer look at the cell, what
is homeostasis?
-HOMEOSTASIS: is the constancy of
the internal environment, that is
optimal for the survival of the living
organism
- Functions of all systems →
ACHIEVE HOMEOSTASIS
- Change in the homeostasis distrust
the optimal environment for survival
3- closer look into the
homeostasis
- Please refer to this slide
- Understand the examples on the:
1) Blood pressure
2) Calcium level
3) Environment temperature
4- Negative and positive
feedback
-Negative feedback: Final event
that is a result of the first event
and reverse to it
-Positive feedback: Final
event that is a result of the
first event and same to it
5- Membranes of cells
→ Cells and organelles are covered by
membranes, this allow different
composition of fluids between
membranes and this achieve variety of
functions
6- Cytoskeleton
→Cytoskeleton: The skeleton of
the cell
Contains 3 main components:
1) Microfilaments (actin
filaments)
2) Intermediate filaments
3) Microtubules
→ Functions of cytoskeleton:
1) Formation of cilia
2) Transporting vesicles
3) Formation of mitotic spindle
4) Formation of pseudopods
5) Contraction of muscles
6)Determination the shape of
the cell

3. TISSUE LFUEL
CELLULAR
LEVEL
-
>
cellsareusuala
C, H,
O
,
N,
P
Molecule
(DNA)
Smooth muscle
Tissue layers
Epithelial
Tissue
Liver
stomach

4. ▪ Human body is composed of several systems, such as cardiovascular
system, renal system, gastrointestinal system
▪ Systems are composed of several organs, for example, gastrointestinal
system is composed of many organs such as the stomach
▪ The stomach is formed of many tissues that achieve certain functions,
tissues are formed of cells
▪ For example on functions:
1)muscle cells contract the stomach to move the food (muscle cells achieve
contraction in any organ, not only the stomach –important for pumping of
the heart-)
2) Secretory cells that secrete enzymes (pepsin, HCL….. etc.)
Respiratory
me me

5. Body
systems
constant
function
of
all
body system
s
& Parameters
E
optimal environment for
living
-
-
-
-
#

6. ▪ Cells are found in the body in a fluid media (body fluids), which is the extracellular matrix
▪ Extracellular matrix is also called the internal environment of the body
▪ Factors of the extracellular matrix such as temperature and concentration of elements (Na+2,
K+, glucose … etc.) are CONSTANT
▪ This constancy is called HOMEOSTASIS, which is defined as the constancy of the internal
environment, that is optimal for the survival of the living organism
▪ Note: Please do not be confused between homeostasis & hemostasis, as hemostasis is the
process where clot is formed when injury to stop bleeding
▪ Change in the homeostasis distrust the optimal environment for survival
▪ Functions of all systems → ACHIEVE HOMEOSTASIS, For example:
1)Respiratory system inhale oxygen into the body to keep it in a certain concentration inside
the body, and cardiovascular system pumps blood to all of the body to provide a certain
concentration of oxygen for all of the body, if these systems are distributed, there will be a
disease
2) Endocrine system produces insulin to store excess glucose that is found in the blood inside
body tissues as a glycogen, if there is no insulin → Hyperglycemia and diabetes
+ cells
E
g
of the internal environment
95 =
-

7. complicatedrocess

8. Integration
▪ Steps of restoring homeostasis:
1) Homeostasis is disrupted by any mechanism
2)Receptors sense the disruption and send messages
(nerve impulses or chemical signals) to the control center,
this is called (input)
→ Control center: any part of the body that control our
organs (e.g. nervous system)
3) Input received is INTEGRATED inside the control center,
and then the control center sends an output to the effector
organs (by nerve impulses or chemical signals)
4) Effector organs receives the output and achieve changes
in the body
5) Homeostasis is achieved
dig
Somestimulus
ais by
controlledcondition
Receptors
=
&
-
-
-
-
Effectors

9. ▪We will study 3 examples on the homeostasis in
details (not that much details ☺):
1) Blood pressure
2) Calcium level
3) Environment temperature

10. ▪1) Blood pressure
Homeostasis
is distributed
Blood
pressure is
decreased
Baroreceptors in
some arteries
sense the change
in pressure
Input
Control center (central nervous
system) receive input & integrate it
Output
Effectors:
1) vasoconstriction
2) Pump increase
3) Kidney absorb
fluids
Homeostasis
is restored
-
this
increases
blood
pressure
heartrate

11. ▪2) Calcium level
Parathyroid
hormone
Kidney will convert
vitamin d from
inactive to active
from
-
-
- - -

12. ▪3) Environment temperature

13. ▪ Negative feedback: Final event
that is a result of the first event
and reverse to it
▪ Example: After Insulin is
secreted because of raised blood
glucose level, blood glucose
falls, this send a message to the
pancreas to stop secreting
insulin
▪ Another example: After
Glucagon is secreted because of
decreased blood glucose level,
blood glucose rises, this send a
message to the pancreas to stop
secreting glucagon
homeostasis
-
> increases
noselevse
-
c cells
m

14. ▪ Positive feedback: Final event that is a result of
the first event and same to it
▪ Example: Born babies!
The cervix start stretching when the baby is
about to be delivered, stretching is sensed by
certain receptors and signal is sent to the control
center, which will integrate the input and send
an output to the cervix to contract more,
contraction is sensed again and the circuit
repeats until the baby is born
Most of feedbacks are negative not positive !
Positive feedback can be harmful !
& inducing of an effect
Oxytocin -
> increases the
contractions
⑳
-

16. ▪ This is a eukaryotic cell,
recognize that organelles
have membranes that
separate them from the
cytoplasm, they contain
different molecular
concentration than the
cytoplasm (e.g. Calcium
ion is higher in the
endoplasmic reticulum
and mitochondria)
4
Both cells and
organalles
have embranes

17. ▪ You can see in the picture the:
1)Ribosomes: Function in the translation of
the RNA to form proteins
2)rough endoplasmic reticulum: modification
of synthesized proteins
3)smooth endoplasmic reticulum: formation of
some macromolecules
4)Golgi: further modification of proteins and
transferring molecules
4
we have different
( composition in compartments
due to membranes
* ↑
* *
-
--
*
& * -
-

18. ▪ You can see here:
1)Lysosomes: granules that contain lytic
enzymes for breakdown of compounds
2)Peroxisome: Function in breaking down
of very long fatty acids and formation of
plasminogen
4

19. ▪ Notice that the mitochondria
have outer and inner
membranes, the space between
these two membranes is called
intermembrane space, and the
space inside the inner membrane
is called the matrix
▪ Composition is different between
the matrix and the
intermembrane space
4
·
-
>
spaceinsideembrane
*
-
A
highconcentration
e
↓
To produceATP

20. FADHE
NADH
E
inner
membrane
-
> Oxidation phosphorelation

21. ▪ As a summary of electron transport chain:
1) Electrons transfer between complexes and this releases energy
2)This energy is used to transfer hydrogen ions from the matrix to the
intermembrane space
3)A lot of hydrogen accumulates in the intermembrane space, and they need to
move again from the intermembrane space (higher concentration gradient) to the
matrix (lower concentration gradient)
4) This returning release energy which is used by ATP synthase to produce ATP
▪ SO, AS A GENERAL IDEA FROM THIS CONCEPT, REMEMBER THAT
DIFFERENT COMPOSITIONS AMONG MEMBRANES IN AND OUT OF THE CELL
IS VERY IMPORTANT PHYSIOLOGICALLY FOR DIFFERENT PURPOSES
4

22. ▪ Cytoskeleton: The skeleton of the
cell
▪ Contains 3 main components:
1) Microfilaments (actin filaments)
2) Intermediate filaments
3) Microtubules
5

24. ▪ Functions of cytoskeleton:
1) Formation of cilia
2) Transporting vesicles
3) Formation of mitotic spindle
4) Formation of pseudopods
5) Contraction of muscles
6) Determination the shape of the cell
by microtubules
By actin filaments
5

25. ▪ Cilia: hairs found in respiratory tract
that functions in excreting the mucous
outside
▪ It’s formed of microtubules as shown in
the picture
▪ Those microtubules are connected
basally to a motor protein that moves
the cilia
5
5
js
j -
n
-
>motor protiens

26. 5
-
>moving
due to
Phosphorelation
microtables and
dephosphorelationo
E 2
in vesicles
cortation
Transl

27. ▪ Microtubules can act as streets for the movement of vesicles inside the cell
anterogradely and retrogradely
▪ Vesicles move on microtubules by protein carriers
▪ This is important for the directed transportation of the vesicles in the cell
5

28. ▪ Microtubules form Mitotic spindle
which is essential for cell division, it
polymerize and bind to the DNA to
separate it for replication, then it
repolymerize again
5
·
I
--
-
-
-
-
-
Polymerizing

29. ▪ Actin filaments forms
pseudopods that is
essential in movement
▪ these pseudopods will
attach to a sight near the
cell by polymerizing actin
filaments, and when it
reaches it, it will detach
from that sight by
depolymerizing actin
filaments and that will
make the cell move
5
activ fillment

30. ▪ Thin filaments moves medially between thick
filaments to shorten the muscles
▪ Note: Thin filaments are actin filaments
5
-

31. 5

32. ▪ Cytoskeleton is important in shape:
1)Neurons: the dendrites are shaped like this to increase the surface area of
the cell so they can collect as much as possible
2)muscle cells :elongated cells, this elongation of the cells makes the
contraction process more efficient
3)red blood cells: They are biconcave as they need to circulate in the body for
long distance and be loaded with oxygen in a short period of time, so if they
are spherical in shape, they won't be able to diffuse to a long distance and
can't be loaded with oxygen sufficiently, this is called spherocytosis
5

33. 1) A process took place that stopped insulin from more releasing
after it achieved it’s function, this process is known as :
a- Homeostasis
b- Hemostasis
c- Negative feedback
d- positive feedback
e- None of the above
2) Rapid growth during puberty causes your body to release
more and more growth hormones. As you grow, more and
more growth hormones are released until puberty is reached,
and then the hormones stop. This represents a :
A- Positive Feedback Response
B- Negative Feedback Loop
C- Both a and b
D- none of the above
3) Which of the following is correct:
A- Hemostasis is defined as the constancy of the internal
environment, that is optimal for the survival of the living
organism
B- Baby’s birth is an example of negative feedback
c- The cytoskeleton is not concerned in cell shape
d- Mitochondria have two membranes
e -None of the above
4)Not a function of cytoskeleton:
A- Formation of cilia
B- Separation between cell compartments
C- Formation of mitotic spindle
D- Transporting vesicles
E- None of the above
Past paper questions !
1 2 3 4
c a d b