BIOLOGY : CELL COMMUNICATION (PART 1)

hello everybody, it is BIOLOGY TIME.
(FOUNDATION IN SCIENCE STUDIES-BIOLOGY-SEM 2)

CELL COMMUNICATION (PART 1 )

Each cell responds only to certain signals, however, and ignores the rest, like a person following the conversation of a person or two individuals in a noisy, crowded room.

The location of the receptor can either be :-

1. Intracellular , for hydrophobic ligands that can cross the membrane
2. Or in the plasma membrane, for hydrophilic ligands that cannot cross the membrane.

MECHANISMS

 

A. SYNAPTIC SIGNALLING

 Chemicals synapse signalling involves

 transmission of signal molecules, called neurotransmitters,

from a neuron over a small synaptic gap to the target cell.

B. ENDOCRINE SIGNALLING

Hormones are released into the organism's circulatory system,

which carries them to the target cells.

 

C. DIRECT CONTACT

Two cells in direct contact with each other may send signals across gap junctions.

 

D. PARACRINE SIGNALLING

 

Secretions from one cell have an effect only on cells in the immediate area.

 

PART 2 COMING SOON