ENDOCRINE SYSTEM

Question 1

define the endocrine system?

Answer 1

consists of glandular cells, tissues and organs whose products supplement the rapid, short term coordinating functions of the nervous system

Question 2

define a hormone?

Answer 2

produced by glands into the blood for target organs

Question 3

list the requirements for hormone efficiency?

Answer 3

stimulus
production
release
circulation
uptake 
2nd messenger

Question 4

list the functions of the endocrine system?

Answer 4

maintain internal homeostasis
support cell growth
co-ordinate development/ reproduction
facilitate responses to external stimuli

Question 5

outline how homeostasis is regulated?

Answer 5

• nerves (neurotransmitters) - fast action, governing response
• hormones - slower action, mainly metabolism, growth, differentiation and reproduction

Question 6

list the similarities between the endocrine and the nervous systems?

Answer 6

• regulate cells and tissues
• act through receptors
• functional overlap between some hormones and neurotransmitters
• excitatory/inhibitory

Question 7

describe a hormone?

Answer 7

• a substance produced by specific cell types usually accumulated in one organ
• transport by blood to target tissue
• stereotypical response (receptors)
• cell to cell communication molecules
• made in glands or cells
• transported by blood
• distant target tissue receptors
• activates physiological response

Question 8

name and describe the types of humeral signalisation?

Answer 8

endocrine - from gland via blood to a distance
neurocrine - via atonal transport and then via blood
paracrine - neighbouring cells of different types
autocrine - neighbouring cells of same type/ secreting cells itself

Question 9

describe the types of hormone transport?

Answer 9

• freely in the blood - catecholamines and most peptides

* specific transport globulins (from liver) - steroids

Question 10

what is the name for a signal molecule?

Answer 10

a ligand

Question 11

state the ways hormones are inactivated?

Answer 11

• target tissue uptake
• metabolic degradation (plasma, liver, kidney)
• excretion in urine
• decreased by transporter binding - low for proteins
• reabsorption and degradation in kidneys

Question 12

name and give an example of the types of hormone classification?

Answer 12

• protein and polypeptide - e.g. growth
• amine - e.g. epinephrine
• steroid - e.g. cortisol

Question 13

describe the rhythms which regulate hormone release?

Answer 13

• circadian - light/dark endogenous rhythm cells and suprwahiasmatic nucleus of hypothalamus
• e.g. melatonin and cortisol
• monthly
• seasonal - day length, atavistic
• developmental - puberty, menopause

Question 14

other than rhythms, describe another method of regulating hormone release?

Answer 14

pulsations/ oscillations - gonadotropins = sensitive target tissue and up-regulate receptors - improved responses

Question 15

describe the functions of the hypothalamus ?

Answer 15

• integrates functions that maintain chemical and temperature homeostasis
• controls release of hormones from anterior and posterior pituitary
• secretes regulatory hormones - RH and RIH
• ‘directs’ pituitary

Question 16

name some examples of releasing and inhibitory hypophysiotrophic hormones released by the hypothalamus?

Answer 16

releasing hormones

• thyrotropin releasing hormone (TRH)
• gonadotropin releasing hormone (GnRH)
• prolactin releasing factor (PRF)
• corticotropin releasing factor (CRH)
• growth hormone releasing factor (GHRH)

inhibitory hormones

• prolactin inhibitory hormone (PIL)
• growth hormone inhibitory hormone (GHIH)

Question 17

name and describe some anterior pituitary hormones?

Answer 17

*growth hormone (GH) - primary hormone, regulates growth, important in metabolism
*thyroid stimulating hormone (TSH) - stimulate thyroid hormone secretion and thyroid gland growth
*adrenocorticotropic hormone (ACTH) - stimulate cortisol by cortex and or,one cortex growth
*follicle stimulating hormone (FSH) -
—female = growth and develop ovarian follicles, promote oestrogen secretion
—make = required to make spermies
*luteinising hormone (LH) -
—female = obi,action, formation corpus luteum in ovary, regulate sex hormones
—male = stimulate cells in testes to secrete testosterone
*prolactin hormone
—female = stimulate boobie development and milk production
—male = involved in testicular function