Endocrine System and Signal Transduction

Identify A

Thymus

Identify B; what does it produce?

Adrenal gland makes adrenaline

Identify C

Pancreas

Identify D; what does it produce?

Pineal gland; produces melatonin

Identify E

Hypothalamus

Identify F

Pituitary gland

Identify G

Thyroid

Identify H

Parathyroid

Identify I

Ovary

Identify J

Testes

What is the first step of signal transduction of cell-surface (transmembrane) receptors?

ligand approaches cell and binds to transmembrane receptor

What is the second step of signal transduction of cell-surface (transmembrane) receptors?

Secondary messenger is produced inside cell (cAMP)

cAMP

cyclic adenosine monophosphate

What is the third final step of signal transduction of cell-surface (transmembrane) receptors?

secondary messenger binds and trigger response in effectors

What is the first step of signal transduction of intracellular receptors?

ligand approaches cell and passes through cell membrane into cell

What is the second step of signal transduction of intracellular receptors?

ligand binds to an intracellular receptor

What is the third final step of signal transduction of intracellular receptors?

ligand-receptor complex regulates gene expression

Positive feedback

speeds up production of chemical signaling

Negative feedback

slows/stops production of chemical singaling

What are four examples of transmembrane receptors?

• acetylcholine receptors

• G protein-coupled receptors (GPCRs)

• epinephrine receptors

• tyrosine kinase receptors

What are three examples of intracellular receptors

• oestradiol

• progesterone

• testosterone

What do intracellular receptors affect?

They affect gene expression

What does the binding to a acetylcholine receptor cause?

Causes the opening of an ion channel in receptor→ causes sodium ions to diffuse into cell

What is the affect of sodium ions in terms of electricity?

Changes the voltage across the plasma membrane

What type of substance is acetylcholine and what does it move between?

• a neurotransmitter

• moves between neuron and muscle fibers

What does the signal transduction of acetylcholine receptors ultimately cause?

depolarization and an action potential between 2 neurons

What type of receptor on the cell membrane is involved with G protein-coupled receptors (GPCRs)

involves a G-receptor protein in the cell membrane

When is the alpha subunit involved in with GPCRs inactive?

when GDP (guanosine diphosphate) is bound

What is the result of the ligand binding to receptor in terms of GPCRs?

It moves GDP to allow GTP to bind

What does the activated G-protein do because of GPCRs? What is the effect?

It splits into 3 subunits (alpha, beta, gamma)→ allows a signal to effectors in the cell

What do epinephrine receptors bind to and what is the result?

binds to a transmembrane protein→ causes the rapid release of glucose into bloodstream

What does the activation of G protein with epinephrine receptors cause?

Causes adenylyl cyclase to become activated

As ____ is activated, ____ is then broken down into ___ (think about glucose utilization)

Glycogen phosphorylase; glycogen→ glucose-1 phosphate

Kinases

enzymes that add a phosphate group from ATP to another specific molecule

Describe where tyrosine kinase receptors are located when insulin attempt to bind to them?

Located in the plasma membrane

Where does the phosphorylation of tyrosine occur?

Occurs inside a cell

What is the “ultimate” result of tyrosine kinase receptors in terms of glucose?

Vesicles containing glucose moves to the plasma membrane

What type of hormones are intracellular receptors?

Steroid receptors

What are the intracellular receptors responsible for?

the development and regulation of sex characteristics (male or female)