Question

Help please!

1. Considering the following cellular signal systems: Endocrine, Paracrine, Autocrine, Cell-Cell contact and Synaptic, please respond: a. What characteristics do they have in common? Please, mention at least two b. How the signal is transported in each one? c. Please, represent with a simple drawing each one of the signaling types d. Which advantages (at least 2) has the synapsis signaling compared to the the endocrine one?

Answer 1

1) a)In multicellular organisms, growth factors, hormones, neurotransmitters, and extracellular matrix components are some of the many types of chemical signals cells use. These substances can exert their effects locally, or they might travel over long distances.

b) •Endocrine signals target distant cells. Endocrine cells produce hormones that travel through the blood to reach all parts of the body.

•Paracrine signals target cells in the vicinity of the emitting cell. Neurotransmitters represent an example.

•Autocrine signals are produced by the target cell, are secreted, and affect the target cell itself via receptors. Sometimes autocrine cells can target cells close by if they are the same type of cell as the emitting cell. An example of this are immune cells.

•Direct contact between cells allows the receptors on one cell to bind the small molecules attached to the plasma membrane of different cell. In eukaryotes, many of the cells during early development communicate through direct contact.

•Synaptic signaling is similar to paracrine signaling but there is a special structure called the synapse between the cell originating and the cell receiving the signal. Synaptic signaling only occurs between cells with the synapse; for example between a neuron and the muscle that is controlled by neural activity.

c) Endocrine

Endocrine cell Blood vessel Signal molecule Target cell

Paracrine

Secretory cell Adjacent target cell

Autocrine
signaling cell target cells local mediator
cell-cell contact
Signaling cell TAIK Target cell
synaptic
Sending cell Neurotransmitter released into synapse Neurotransmitter Neurotransmitter attached to receptor Receiving cell/

d)•many cells can be targeted at once.

•Since neurotransmitters not diluted by blood, receptors need only have low affinity for the neurotransmitter.