lecture 1

Question 1

What is a hormone

Answer 1

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

Question 2

What is endocrine signalling

Answer 2

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

Question 3

true or false; a hormone is a ligand

Answer 3

true

Question 4

What hormone is an example of endocrine signalling

Answer 4

insulin

- secreted from the B-cells of the pancreas

Question 5

true or false; hormones also maintain homeostasis

Answer 5

true

Question 6

What is Autocrine signalling

Answer 6

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

Question 7

What is an example of an Autocrine signal

Answer 7

growth factors

Question 8

What are Paracrine signals

Answer 8

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

Question 9

What is an example of a paracrine signal

Answer 9

acetylcholine at the neuromuscular junction

Question 10

What is cell-cell signalling

Answer 10

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

Question 11

What is an example of cell-cell signalling

Answer 11

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

Question 12

How do hormones maintain homeostasis

Answer 12

via a feedback system

Question 13

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

Answer 13

by activating receptors

Question 14

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

Answer 14

true

Question 15

true or false; a receptor recognizes one hormone only

Answer 15

true eg. glucagon receptors and insulin receptors

- makes receptors good targets for medicines

Question 16

What are the 2 main classes of hormones

Answer 16

steroid

non-steroid

Question 17

Where does a steroid act?

Answer 17

inside the cell; has intracellular receptors

Question 18

Where does a non-steroid act?

Answer 18

outside the cell

Question 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

Answer 19

true

Question 20

Define receptor

Answer 20

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

Question 21

Define signal transduction

Answer 21

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

Question 22

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

Answer 22

true

Question 23

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

Answer 23

true

Question 24

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

Answer 24

transmembrane proteins

Question 25

true or false; hormones also influence growth and development

Answer 25

true