Cell Signalling ✅ Flashcards
What are the two basic types of cell communication? What is another word for cell communication?
The two basic types of physiological signals (messengers) are:
1) electrical signals
2) chemical signals
How do cells have electrical signals? What changes for them to occur?
Electrical signals are changes in a cell’s membrane potential.
How do cells have chemical signals? What changes for them to occur?
- cells secrete molecules into the extracellular fluid
What are the cells called that receive electrical and chemical signals?
target cells
Which form of communication is most frequent?
chemical communication
What are the three basic methods of cell-to-cell communication?
- DIRECT CYTOPLASMIC TRANSFER - electrical and chemical signals through gap junctions that connect adjacent cells.
- LOCAL COMMUNICATION- by chemicals that diffuse through the extracellular fluid.
- LONG-DISTANCE COMMUNICATION- through a combination of electrical signals carried by nerve cells and chemical signals transported in the blood.
Explain direct cytoplasmic transfer.
DIRECT CYTOPLASMIC TRANSFER of electrical and chemical signals through gap junctions that connect adjacent cells.
Explain local communication.
LOCAL COMMUNICATION by chemicals that diffuse through the extracellular fluid.
Explain long-distance communication.
LONG-DISTANCE COMMUNICATION through a combination of:
- electrical signals carried by nerve cells
- chemical signals transported in the blood.
What is a gap junction? What does it form? Which type of signal passes through them?
- A gap junction is a cytoplasmic connection between adjacent cells
(Protein channels create cytoplasmic bridges between the cells)
When gap junctions are open, ions and small molecules (eg. amino acids, ATP, AMP) pass directly from one cell’s cytoplasm to the next.
- Gap junctions are the only means by which electrical signals can pass directly from cell to cell,
What happens when channels open in the gap junction?
the connected cells function like a single cell with multiple nuclei.
How do chemical signals distribute?
by diffusion through the interstitial fluid.
How is local communication accomplished?
By the diffusion of paracrines and autocrines.
What is a paracrine?
A chemical that is secreted by a cell to act on cells very near it.-
- acts short-distance
- on neighbouring cells
What is an autocrine?
A signal molecule that acts on the cell that secreted it.
- cell creates a hormone which later acts on itself
Why is the effective range of a chemical signal restricted to adjacent cells?
Because distance is a limiting factor for diffusion.
How does the nervous system communicate?
Through chemical and electrical signals.
How does the endocrine system communicate?
Through hormones.
Explain the long-distance communication endocrine system.
- Hormones are secreted by endocrine glands or cells into the blood (and distributed all around the body).
- Only target cells with receptor for the specific hormone will respond to the signal.