Cell to cell communication

Question 1

What is the neuroendocrine system

Answer 1

The sets of neurons, glands and non-endocrine tissues, and the neurochemicals, hormones, and humoral signals they produce and receive, that function in an integrated manner to collectively regulate a physiological or behavioral state. (Nervous system and glands like thyroid pituritart etc.)

Question 2

What are the 2 types of cell to cell communication?

Answer 2

Juxtracrine or direct communication
Indirect communication (when cells aren't in direct contact).

Question 3

Direct communication

Answer 3

Cells need to be in physical contact with each other. The communication is ensured by specific proteins. They either have gap junctions or gap junction channels.

Question 4

What do gap junctions do in direct communication?

Answer 4

Gap junction connect the inside of the two adjacent cells to each other and permit rapid transfer of various substances and electrical impulses between adjacent cells. examples are in the heart muscle and in the wall of the gastrointestinal tract.

Question 5

Indirect communication

Answer 5

Communicating cells are not in direct contact; often (very) far away from each other. examples are the brain instructing muscles to contract, nervous system tells heart to beat faster etc.

Question 6

What are the 5 messenger molecules indirect communication requires?

Answer 6

Endocrine signaling
Paracrine signaling
Autocrine signaling
Neurocrine signaling
Neurotransmission

Question 7

Endocrine signaling

Answer 7

The messenger molecule is called a hormone.
Produced by an endocrine gland. Reaches target cells via bloodstream which may travel long distances.
Examples:
•Thyroid gland (Thyroid hormones; e.g., thyroxine)
•Pancreas (insulin and glucagon)
•Testes and ovaries (testosterone, progesterone, estrogens)

Question 8

Paracrine signaling

Answer 8

The messenger molecule is called a Paracrine (hormone).
Produced by a paracrine gland or cell. Does not enter the bloodstream but remains in the fluid surrounding the paracrine cell (interstitial space). This type of communication is quite common in the gastrointestinal tract.

Question 9

Autocrine signaling

Answer 9

The messenger molecule is called an autocrine (hormone). Produced by an autocrine cell. Does not enter the bloodstream. Remains in the interstitial fluid and acts on the very same cell that produced it. This type of communication is quite common in the immune system and in the ovaries.

Question 10

how do Neurons/ nerve cells communicate?

Answer 10

They communicate with each other, with skeletal muscle, cardiac muscle, smooth muscle, and glands using a highly specific structure called synapse

Question 11

What is a synapse?

Answer 11

A synapse is the ending of a nerve cell where it communicates to other nerve cell ends. Messenger molecules gets released into the synaptic cleft where the messenger molecules are then released to the neighboring nerve ending.

Question 12

Neurotransmission

Answer 12

The messenger molecule is called a neurotransmitter. Produced by a neuron (nerve cell). Enters a special gap (called synapse) between the neuron and the another neurone it communicates with.

Question 13

Neurocrine signaling

Answer 13

Messenger molecule is called neurohormone. Produced by a neuron. Reaches target cells via bloodstream. Also called neurosecretion. Typical examples: oxytocin and vasopressin produced by a specific region of the brain
Note that this cell-to-cell communication is an intriguing combination of endocrine communication and neurotransmission.

Question 14

What is a receptor?

Answer 14

A chemical group or molecule (such as a protein) on the cell surface (or in the cell interior) that can bind a specific chemical group, molecule, or virus.

Question 15

3 types pf cells referring to receptors

Answer 15

Secreting cell
Non target cell
Target cell

Question 16

How does a secreting cell find the target cell.

Answer 16

The messenger molecule can evoke its effect only if the target cell has specific receptors. Binding of messenger molecule to change in cell function. If the cell has no receptor there will be no effect.

Question 17

Cell surface receptors + 4 steps of receptors.

Answer 17

Most messenger molecules cannot pass through cell membrane they instead bind to cell surface receptors. Most of the hormones and neurotransmitters work this way.

1. Messenger molecule binds to the surface receptor.
2. Receptor molecule changes its shape.
3. Various changes are triggered in the cell.
4. Cellular function changes

Question 18

7 main steps of neurotransmission

Answer 18

1. A nerve impulse reaches the presynaptic terminal.
2. Ca2+ enters the presynaptic terminal.
3. Ca2+ concentration increases in the presynaptic terminal.
4. Synaptic vesicles adhere to the presynaptic membrane leading to ‘Docking’.
5. Neurotransmitter is released into the synaptic cleft.
6. Neurotransmitter binds to its receptors on the other side.
7. Effect.