endocrine intro

Question 1

what is a hormone

Answer 1

molecules secreted by endocrine cells into the circulating blood that act on cells that express their specific receptors

Question 2

nervous system and endocrine similarities and differences

Answer 2

independant or together
some molecules are both hormones and neurotransmitters
both bind with specific receptors
secretion of both uses same mechanisms

Question 3

what are the characteristics of horomes

Answer 3

cell specificity
efficaious at low concentrations
feedback control

Question 4

autocrine

Answer 4

cell produces its own hormone that acts on itself

Question 5

paracrine

Answer 5

cell produces hormone that works on its neigbour

Question 6

endocrine

Answer 6

in the blood

Question 7

what limits responses

Answer 7

negative feedback-target cell has negative biological response to endocrine cell
reduces the effect of the stimulus- signal is continuously stimulating hormone secretion by endocrine cell

Question 8

what continues until stopped by an explosive event

Answer 8

positive feedback- the target cell has a posivie biological response to the endocrine cell- increases the effect of the stimulus- a signal is continuously stimulating hormone secretion by the endocrine cell

Question 9

feed forward mechanism

Answer 9

anticipatory responses that start a feedback loop in anticipation of a change that is about to occur
usually neural reflexes
-heart rate increasing before starting a race

Question 10

what are the components of a negative feedback loop

Answer 10

variable
sensor/ monitor
integrator and set point
effector

Question 11

what is normal body temperature

Answer 11

35.5-37.7 or 96-99.9

Question 12

example of a integrator

Answer 12

temperature control centre when cold

Question 13

peptide hormones

Answer 13

chains of amino acids as short as 3 and up to very large proteins

water soluble

Question 14

example of peptide hormone

Answer 14

insulin

Question 15

steroid hormones

Answer 15

derived from cholesterol and relatively lipid soluble

Question 16

another name for tyrosine hormone

Answer 16

amine hormones

Question 17

what are the two groups of tyrosine hormones

Answer 17

catecholamines
-small and hydrophillic

thyroid hormones
-large and lipophilic

Question 18

what are tyrosine hormones derived from

Answer 18

the amino acid tyrosine

Question 19

what are the mechanisms of hydrophilic hormones

Answer 19

lead to activation of intracellular enzymes to generate second messengers that amplify the peptide hormone signal

Question 20

what are the two mechanisms of hydrophilic hormones

Answer 20

g protein coupled second messengers- cAMP; intracellular calcium

phosphorylation is a common element of intracellular signalling (kinases/ phosphatases)

Question 21

mechanism of action of lipophilic hormones

Answer 21

cytoplasmic or nuclear receptors
gene activation- genomic action
protein synthesis
in some cells there are surface receptors that activate second messenger systems- non genomic action