lecture 5 (intercellular communication)

Question 1

how does direct communication occur

Answer 1

gap junctions and tunnelling nanotubes

Question 2

how does indirect communication occur

Answer 2

chemical messengers and mechanosignals

Question 3

direct communication through gap junctions

Answer 3

-pore size very small for ions
-two cells are very close, gap junctions are tiny and have 100+ between cells)

Question 4

direct communication through nanotubes

Answer 4

-much longer than gap junctions
-big, for proteins

Question 5

indirect communication through mechanosignals

Answer 5

-as cells move, they tug on filamentous proteins of the extracellular space
-as large molecules move by the cell, they can bend surface filaments

Question 6

indirect communication through chemical messengers

Answer 6

chemical leaves the cell and goes to target

1. paracrines/autocrines
   paracrines: signal to nearby cell
   autocrines: signal to self
2. neurotransmitters: goes down from axon terminal to receptor

3.

Question 7

direct communication through chemical messengers: hydrophilic and hydrophobic

Answer 7

hydrophilic: secreted from endocrine cell through exocytosis into blood, dissolves

hydrophobic: secreted by diffusion, bound to carrier proteins in blood