This document discusses different types of intercellular signaling pathways: - Contact-dependent signaling occurs when signal molecules remain bound to the producing cell and only influence directly contacting cells. This is important in development and the immune system. - Paracrine signaling involves diffusion of chemical messengers between nearby cells over short distances. - Synaptic signaling is a form of paracrine signaling where nerve cells transmit signals at synapses. - Endocrine signaling involves hormones released by endocrine glands that travel through the body and act on distant target cells, causing slow but long-lasting responses. - Autocrine signaling occurs when cells respond to substances they secrete themselves, which is common in tumor cell growth and embryonic

1. INTERCELLULAR SIGNALLING
PATHWAYS
Presented by: Manju Jakhar
Rollno.20PPC008

2. What is cell signaling
• All cells receive and respond to signals their surroundings
• Communication between cells.

3. INTERCELLULAR SIGNALING
• Intercellular signals can travel all
throughout the body.
• This allows certain glands within
the body to produce signals
which take action on many
different tissue across the body.

4. TYPES OF INTERCELLULAR
a) Contact-dependent(juxtracrine)
• When the signal molecule remains
bound to the cell that produced it
and therefore, will only influence
cells that directly contact it, then
this type of intercellular signaling is
known as contact dependent
signaling.
• This type of signaling is very
important in the development of
multicellular organism ans in the
immune system.

5. b. Paracrine
• Cells that are near one another
communicate through the release of
chemical messengers (ligands that
can diffuse through the space
between the cells).This type of
signaling in which cells
communication over relatively sort
distances, is known as paracrine
signaling.
• Paracrine signaling depends on local
mediators that are released into the
extracellular space and act on
neighboring cells.

6. c. Synaptic
• Synaptic signaling is unique
example of paracrine signaling in
which nerve cells transmit signal
with the help of synapse.
• Synapse is the junction between
two nerve cells where signal
transmission occurs.

7. d. Endocrine
• This is a type of communication
occuring between distant cells and
mediated by hormones.
• The hormones are released by
endocrine cells of the body.
• Signaling molecules(hormones)
travel through the body and act
upon particular target cells.
• They cause slow but long lasting
responses.

8. e. Autocrine
• In autocrine signaling, cells respond
to substances that they themselves
release.
• Many growth factors act in this
fashion and cultured cells often
secrete growth factors that
stimulate their own growth and
proliferation.
• This type of signaling is particularly
common in tumor cells, many of
which overproduce and release
growth factors that stimulate
inappropriate, unregulated
proliferation of themselves as well
as adjacent non-tumor cells; this
process may lead to formation of
tumor mass.
• Important during embryonic
development.
• Blood platelates secretes
eicosanoids to influence their own
activity.