Chemical/neural Signalling

Question 1

Cell signaling

Answer 1

Ligand bonds to G protein linked receptor, change in shape caused intercellular molecule to become active (GDP into GTP), travels to an enzyme (usually adenylyl Cyclase) which results in cellular response

Q second messenger exists in the cell and is usually cAMP

Question 2

Three families of hormones

Answer 2

Polypeptides and amino acids are not lipid soluble and bind to receptors on cell surface

Steroids are lipid soluble and bind inside cell

Question 3

Function of hormones

Answer 3

Antidiuretic h: helps increase water retention

Oxytocin: causes uterus to contract

Trophic hormones have another gland as a target:

Follicle stimulating h/ LH influence release of hormones from gonads

Nontrophic:

Prolactin (milk production)

MSH stimulates pigment

Endorphins influences pain receptors

Question 4

Pineal gland

Answer 4

Secretes melatonin

Question 5

Thyroid hormones/ t3 and t4

Answer 5

These two horses regulate our metabolism and have to do specifically with oxygen consumption

Operates through negative feedback system…

Hypothalamus -> TSH -> anterior pituitary -> TSH -> thyroid -> t3/t4

This continues until there is too much TSH, t3 or t4

Question 6

Calcitonin/parathyroid hormone

Glucagon/insulin

Answer 6

These hormones reduce/increase calcium levels in the blood, respectively

The second pair of hormones maintains blood glucose levels (glucagon raises)

When homeostasis is not ideal, either of them go into effect

Question 7

Sodium potassium pump

Answer 7

Pumps sodium out of the neuron (happens more often)

Pumps potassium into the neuron

Question 8

Graded potential

Answer 8

Hyperpolarization: more negative than resting potential

Depolarization: more positive than resting potential

Question 9

Acetylcholine

Answer 9

The only neurotransmitter that stimulates muscle cells to contract

Curare, a deadly poison, binds to their receptors so the muscles cannot contract