Helpful for understanding the mitosis with some live images and short and simple description of prophase, metaphase, anaphase, telophase and cytokinesis
Helpful for understanding the mitosis with some live images and short and simple description of prophase, metaphase, anaphase, telophase and cytokinesis
Introduction
Think your cells are just simple building blocks, unconscious and static as bricks in a wall? If so, think again! Cells can detect what's going on around them, and they can respond in real time to cues from their neighbors and environment. At this very moment, your cells are sending and receiving millions of messages in the form of chemical signaling molecules!
In this article, we'll examine the basic principles of how cells communicate with one another. We'll first look at how cell-cell signaling works, then consider different kinds of short- and long-range signaling that happen in our bodies.
Overview of cell signaling
Cells typically communicate using chemical signals. These chemical signals, which are proteins or other molecules produced by a sending cell, are often secreted from the cell and released into the extracellular space. There, they can float – like messages in a bottle – over to neighboring cells.
Tissues, Organs and Systems: The images have big font size and reduced background color. Useful for smartphones, classroom and printouts. The rest is standard stuff.
This Presentation provides an outline knowledge about Cellular Communication, Steps involved, Its Types, Signal Transduction, Secondary Messenger , Receptors with some Interesting Facts and Current Trends. An assignment for the subject, Cellular and Molecular Pharmacology, 1st year M.Pharm, 1st semester.
Cell Communication, Cell Junction and Cell Signaling.pptxSheetal Patil
-Cellular Communication
-There are three stages of cell: communication
a.Reception
b.Transduction
c. Response
-Receptors And Ligands
There are two basic types of receptors:
a.Internal receptors
b.Cell surface receptors
-Internal receptors-often steroid hormones
-There are several different types of ligands
a.Hydrophobic ligands
b. Water soluble hydrophilic ligands
-Three stages of cell communication
-How insulin works
Cell Junction
-There are three types of cell junctions:
1.Adhesive (Anchoring) junctions
2.Tight Junctions
3.Gap Junactions
-The two main kinds of adhesive cell-cell junctions are:
a.Adherens junctions
b.Desmosomes
a. Adherens junctions:
Adherens junction is the cell to cell junction, which connects the actin filaments. In adherens junction, the membranes of the adjacent cells are held together by some transmembrane proteins called cadherins.
b. Desmosome
Desmosome is a cell to cell junction, where the intermediate filaments connect two adjacent cells. Desmosome is also called macula adherens. Desmosomes function like tight junctions. The trans-membrane proteins involved in desmosome are mainly cadherins.
2. Tight Junctions
The cell membranes are connected by strands of trans-membrane proteins such as claudins and occludins.
Tight junctions bind cells together, prevent molecules from passing in between the cells, and also help to maintain the polarity of cells.
-Functions of Tight Junctions:
Another function of tight junctions is simply to hold cells together.
3. Gap Junction
Gap junctions are a type of cell junction in which adjacent cells are connected through protein channels. Gap junctions are made up of connexin proteins. Groups of six connexins form a connexon, and two connexons are put together to form a channel that molecules can pass through. Other channels in gap junctions are made up of pannexin proteins.
-Functions of Gap Junction
The main function of gap junctions is to connect cells together so that molecules may pass from one cell to other.
This allows for cell-to-cell communication.
-Cell Signaling
Cell signaling is the process of cellular communication within the body. The binding of extracellular signaling molecules to their receptors
-Modes of cell-cell signaling
1.Direct cell-cell signaling
2. Signaling by secreted molecule
a.Endocrine signaling:
-E. g. hormones produced by endocrine glands including pituitary, pancreas, adrenal, parathyroid glands etc.
b.Paracrine signaling:
-E.g. action of neurotransmitters in carrying signals between nerve cells at a synapse.
c.Autocrine signaling:
-When interleukin-1 is produced in response to external stimuli, it can bind to cell-surface receptors on the same cell that produced it.
d.Synaptic signaling:
-Types of signaling molecules
a.Nitric oxide
b.Carbon monoxide
c.Neurotransmitter
d.Peptide hormone
-Intracellular signaling pathway activated by an extracellular signal molecule
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The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
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We all have good and bad thoughts from time to time and situation to situation. We are bombarded daily with spiraling thoughts(both negative and positive) creating all-consuming feel , making us difficult to manage with associated suffering. Good thoughts are like our Mob Signal (Positive thought) amidst noise(negative thought) in the atmosphere. Negative thoughts like noise outweigh positive thoughts. These thoughts often create unwanted confusion, trouble, stress and frustration in our mind as well as chaos in our physical world. Negative thoughts are also known as “distorted thinking”.
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Students, digital devices and success - Andreas Schleicher - 27 May 2024..pptxEduSkills OECD
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2. • How does a cell, tissue, or organ develop its shape?
• How does our body make muscle tissue in both our legs and neck? How does it
know to make special muscle for the heart?
• These are topics of morphogenesis- this happens through cell-to-cell
communication. It is how differentiated cells become more organized into tissues
and organs.
• In order to develop this specialized tissue, it is necessary to understand three
mechanisms requiring cell-to-cell communication:
• Cell adhering
• Cell shape changing
• Cell signaling
3. Cell interaction
(communication)
• Cell interaction starts at the cell
membrane.
• There are various proteins either
embedded in the cell membrane,
attached to it, or secreted through it.
• These cells are responsible for how cells
interact.
• A receptor id one type of protein. It
grabs other proteins.
• They could be proteins sent
from another cell (like a
chemical)
• They could be a protein
attached to another cell
(another receptor)
4. Receptors
• When the protein receptors are the same on both cells it is called
homophilic binding. When they are different, it is referred to as
heterophilic binding.
• Proteins send from cells to go to others are call signaling proteins
(ligands)
• When cells are neighboring (adjacent), it is called juxtacrine
signaling
• When cells are a short distance away it is called paracrine
signaling
5. Adhesion and
Sorting
• Embryo cells display selective
affinity.
• In lab experiments, they self-
segregate.
• Certain cells will get together
with others
• Groups of cells will segregate
themselves as well
6. Thermodynamic Model of Cell Interactions
• Cells don’t sort by random. It is in a certain order
• The differential adhesion hypothesis states that:
• How cells sort themselves depends on the differences they have
in adhesion
• Cells move to be near cells with similar adhesion strength to
maximize their bonding.
• Recall the three germ layers. In a lab setting, cells from the three
layers were mixed in a solution.
• Not only did endoderm cells stay with other endoderm cells, they
were internal to mesoderm cells.
• The cells still grouped and made their spatial boundaries
7. Cadherins and Cell
Adhesion
• Cadherins- these are
adhering proteins that
adhere to cadherins on
adjacent cells.
• They are attached to the
membrane and anchored
inside the cell by proteins
called catenins.
• A good example of this
phenomenon is in your
skin (epithelial tissue)
8. The Extracellular Matrix as a Source of
Developmental Signals
• An extracellular matrix (EM) is merely the environment around cells.
The EM is very important for cell movement, adhesion, and
development of epithelial tissue.
• The EM can be made up of various materials:
• Proteoglycans- help cells send signals to other cells (especially
paracrine factors)
• Laminin- forms part of the Basal Lamina, which is a sheet that
epithelial cells connect to
• Fibronectin- this is like paving the street on which cells migrate
9. Integrins
• Integrins are receptors
embedded in cells that can bind
proteins on the inside of the
cell with proteins of the
extracellular matrix (like
fibronectin)
10. Epithelial-Mesenchymal Transition (EMT)
• EMT is a series of events where epithelial cells are transferred to mesenchymal
cells
• How does this happen?
• Paracrine factors from neighboring cells cause the down regulation of the
expression of cadherins (downregulating mean reducing the receptors)
• They then release their attachment to other cells, or integrins. They also
become unattached from the basal lamina as well.
11. Cell Signaling
• Induction and Competence
• Development depends on the exact arrangement of tissues and
cells.
• Induction- when cells with different properties interact. This
has two components:
• Inducer-the tissue that makes the signal that changes cell
behavior
• Responder- the target tissue (the tissue receiving the
signal)
• Competence- The ability of a cell to respond to an induction
12. Paracrine Factors: Inducer Molecules
• How are inducer signals transmitted?
• Juxtacrine interaction- adjacent cells (they are touching)
• Paracrine interaction- cells within a roughly 15 cell radius
• Autocrine interaction- when the same cell is the recipient (this is
a rare occurrence)
• Morphenogens- these are paracrine chemicals that cause different
forms of genetic expression based on their concentration.
13. Signal Transduction
Cascades
• A signal transduction cascade
is the process that starts
when the ligand is bound to
the receptor.
• It causes a series of
reactions within the
cytoplasm of the cell
14. Juxtacrine Signaling for Cell Identity
• Proteins from the inducting cell are going to interact with adjacent
responding cells.
• There are three juxtacrine factors widely used:
• Notch proteins
• Cell adhesion molecules
• Eph receptors/ephrin ligands
• Notch- when this receptor is activated on the outside of the cell, the
end on the cytoplasmic side breaks off and goes to the nucleus to
make changes in gene expression.