1

Physiology Exam 1 Study

Chapter 6 Communication & homeostasis

2

What are the two basic physiological signals?

3

-Chemical -Electrical

4

What are the basic methods of cell-cell communication?

5

- Direct cytoplasmic transfer- Gap junctions- Contact-dependent signals- Local communication- Long distance communication

6

Which method of cell-to-cell communication occurs by chemicals that diffuse through the extracellular fluid?

7

-Local Communication

8

This method of cell-to-cell communication involves the transfer of chemical and electrical signals between adjacent cells.

9

-Gap junctions

10

Where would you expect to find Gap Junctions in the body?

11

-Heart-Smooth muscle of the GI tract

12

What are the cells that receive electrical or chemical signals called?

13

-Target Cells

14

What is the simplest form of cell-to-cell communication?

15

-Gap junctions

16

A gap junction forms from the union of membrane-spanning proteins called____.

17

-Connexon

18

When do connected cells function like a synctium?

19

-When the gap junction (connexon) is open.

20

What is the only means by which electrical signals can pass directly from cell to cell?

21

-Gap junctions

22

What method of cell-to-cell communication utilize Cell Adhesion Molecules (CAMs) to transfer signals?

23

-Contact Dependent

24

How is local cell-to-cell communication accomplished?

25

-Paracrine signaling-Autocrine signaling

26

If a chemical signal acts on the cell that secreted it, it is called an _____ signal.

27

-Autocrine

28

If a chemical acts on cells in the immediate vicinity of the cell that secreted it, its is called ____ signal.

29

-Paracrine

30

If a cell secretes chemicals that act on distal cells it is a ____ signal.

31

-Endocrine

32

What is secreted by neurons to act on itself or neighboring cells?

33

-Neuromodulators

34

What are regulatory substances that mediate immune responses?

35

-Cytokines

36

Why are paracrine and autocrine signals only able to reach adjacent cells?

37

-Because both of these signals reach their targets by diffusing through the interstitial fluid. Diffusion is limited by distance.

38

Most long-distance communication between cells is the responsibility of what two organ systems?

39

-Nervous system-Endocrine system

40

An electrical signal travels along a ___ until it reaches the very end of the cell, where it is translated into a ____ .

41

Neuron,

Neurocrine

42

If a neurocrine diffuses into the blood it is called a ____.

43

Neurohormone

44

If a neurocrine acts more slowly as an autocrine or paracrine signal, it is called a ______.

45

Neuromodulator

46

If a neurocrine has a rapid effect it is called a _____.

47

Neurotransmitter

48

What are Cytokines?

49

Cytokines are regulatory peptides that act close to the site where they secreted.

50

True or False? Cytokines are stored much like hormones?

51

False(Cytokines are produced on demand.)

52

True or False? A cytokine can act as an autocrine and a paracrine.

53

-True

54

Where are receptor proteins located?

55

-Cytosol-Cell membrane-Nucleus

56

This type of receptor mimics the effect of the naturally occuring ligand?

57

-Agonist

58

Are First Messengers Lipophilic or Lipophobic?

59

-Lipophilic, they are able to enter the cell.

60

Which signal molecule is unable to enter the cell?

61

-Lipophobic

62

What are the four classes of membrane receptors?

63

- Ligand-gated ion channels- Intergrin linked to cytoskeleton- G protein-coupled receptor with

seven membrane- Receptor Enzyme

64

What is the result of a ligand binding to a ligand gated channel?

65

-Channel opens or closes

66

Which type of regulation results in the reduction in the number of receptors and/or binding affinity for the ligand?

67

Down-regulation

68

What is the result of a ligand binding to a G protein coupled receptor?

69

-The G-protein receptor opens an ion channel or alters enzyme activity

70

Which membrane receptor results in the activation of an intracellular enzyme?

71

-Enzyme receptor

72

Which membrane receptor result in a change to the cytoskeleton?

73

-Intergrin

74

Which of the four categories of membrane receptors do NOT use signal transduction?

75

-Ligand gated