Chapter 5(Mechanisms of inter cellular communication) Flashcards Preview

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Flashcards in Chapter 5(Mechanisms of inter cellular communication) Deck (38):
1

What is a gap junction? What about coupling ?

link adjacent cells and are formed by plasma membrane proteins called connexins. Electrical impulse directly to the other cell. Direct electrical and metabolic coupling

2

Where are gap junction common?

smooth and cardiac muscle

3

How do chemical messengers work?

When one cell releases a chemical into the interstitial fluid and another cell called the target cell responds to it.

4

Explain Paracrines and give an example.

Released by cell, moves to target cell by diffusion
Paracrines- act on neighboring cells. Histamine.

5

What are autocrines?

Act on the cell that releases it.

6

What is a neurotransmitter? Two properties of it.

Messenger of nervous system.
Diffuses to very close target cell
Released from neuron by exocytosis

7

What is the site called where junction occurs between neurotransmitter and cell?

Synapse.

8

Give an example of neurotransmitter and how it works?

Acetylcholine, causes contraction of skeletal muscle.

9

What are hormones? Two properties of them.

Chemical messenger of the endocrine system.
Released from endocrine gland into blood
Transported in blood to target

10

What are the target cells for hormones?

cells in body with receptors specific to the hormone

11

What are neurohormones?

Released from neuron into blood where it acts in manner similar to hormones

12

What are cytokines classified as

peptide/ protein

13

4 characteristics of cytokines

Can be transported in blood
Released by most cell types
Involved in cell development, differentiation, and immune response
Often act on a wide range of targets

14

What is the most important chemical characteristic?

Whether or not the messenger can dissolve in water or cross the lipid bilayer in the plasma membrane.

15

Two classifications and why?

Lipophillic. Lipid soluble and can cross plasma membrane- do not dissolve in water.
Hydrophilic. water soluble and do not cross plasma membrane.

16

Name the chemical classes of messengers. 5.

Amino acids
Amines
Peptides
Steroids
Eicosanoids

17

What do amino acids function as? What are the 4? Lipophillic or hydrophillic?

Neurotransmitters. Glutamate
Aspartate
Glycine
GABA (gamma-amino butyric acid)
Hydrophillic.

18

What are amines derived from? What group do they include?

Amino acids. Catecholamines, derived from tyrosine.

19

Examples of amines.

Dopamine, norepinephrine, epinephrine

20

Serotonin derived from? Histamine? Thyroid hormones?

Tryptophan, histadine, tyrosine

21

Amines except for thyroid hormones are all?

Lipophobic.

22

What is Most abundant class of chemical messengers
Lipophobic?

peptide/ protein. Yes.

23

Peptide usually refers to what?

Chains smaller than 50 amino acids.

24

proteins are usually what?

more than 50 amino acids.

25

Steroid messenger derived from what?

Cholesterol.

26

All of the steroid messengers function as what?

Hormones

27

Steroid lipophillic or lipophobic?

Lipophillic.

28

Lipophillic messengers released how? How is release regulated?

Diffusion. By regulating rate of synthesis

29

Lipophobic messengers released how

Exocytosis

30

How many amino acids are essential? How many produced by body? How many of those are neurotransmitters

9,11,3

31

After amino acid synthesis, neurotransmitters transported into where?

Secretory vesicles.

32

What is synthesized from glucose ?

Glutamate and aspartate

33

What is GABA synthesized from

glutamate

34

All amines derived from Synthesized where?

Amino Acids. In the cytosol.

35

Which chemicals diffuse through interstitial fluid?

Paracrines, autocrines,most Ctyokines and neurotransmitters

36

Which chemical are transported in blood?

Hormones, neurohormones and some cytokines

37

To be transported in dissolved form, messenger must be?

Hydrophillic

38

How long a hormones persists in the blood depends on?

The half-life of that hormone