lecture 1 Flashcards Preview

106: Receptors and Cellular signalling > lecture 1 > Flashcards

Flashcards in lecture 1 Deck (25):
1

What is a hormone

- chemical substances
- made from the endocrine glans (ductless)
- circulated in the blood stream
- trigger signal transduction events via receptors on target cells

2

What is endocrine signalling

- hormones are secreted from the endocrine cells where they then travel in the blood stream to the receptors of distant target cells (cell membrane)

3

true or false; a hormone is a ligand

true

4

What hormone is an example of endocrine signalling

insulin
- secreted from the B-cells of the pancreas

5

true or false; hormones also maintain homeostasis

true

6

What is Autocrine signalling

Autocrine signals act upon the same cell type they are released from

7

What is an example of an Autocrine signal

growth factors

8

What are Paracrine signals

paracrine signals are released from cells to act upon adjacent cells
- the secretory cell releases the extracellular signal which then binds to the receptors of an adjacent target cell

9

What is an example of a paracrine signal

acetylcholine at the neuromuscular junction

10

What is cell-cell signalling

The extracellular signal is attached to the cell membrane of the cell which initiates the signalling; which makes direct contact with the target cell

11

What is an example of cell-cell signalling

Immune system; T-cell activation of proteins on antigen presenting cells

12

How do hormones maintain homeostasis

via a feedback system

13

how do hormones and other extracellular signals initiate a chain of events in the cell?

by activating receptors

14

true or false; receptors are strategically poised to control what happens inside the cell

true

15

true or false; a receptor recognizes one hormone only

true eg. glucagon receptors and insulin receptors
- makes receptors good targets for medicines

16

What are the 2 main classes of hormones

steroid
non-steroid

17

Where does a steroid act?

inside the cell; has intracellular receptors

18

Where does a non-steroid act?

outside the cell

19

true or false; only when the hormone engages with the correct receptor can it activate the receptor and trigger intracellular signalling leading to physiological response

true

20

Define receptor

a molecule on the surface or within a cell that recognizes and binds with specific molecules producing a specific effect in the cell eg. the cell-surface receptors for antigens or cytoplasmic receptors for steroid hormones

21

Define signal transduction

cascade of processes by which an extracellular signal interacts with a receptor at the cell surface, causing a change in the level of a second messenger and ultimately effects a change in the cells functioning

22

true or false; signal transduction enables extracellular signals to be transmitted into responses

true

23

true or false; receptors trigger changes in cellular chemicals which produces these responses

true

24

What kind of proteins are the receptors for non-steroid hormones

transmembrane proteins

25

true or false; hormones also influence growth and development

true