define the endocrine system?
consists of glandular cells, tissues and organs whose products supplement the rapid, short term coordinating functions of the nervous system
define a hormone?
produced by glands into the blood for target organs
list the requirements for hormone efficiency?
stimulus production release circulation uptake 2nd messenger
list the functions of the endocrine system?
maintain internal homeostasis
support cell growth
co-ordinate development/ reproduction
facilitate responses to external stimuli
outline how homeostasis is regulated?
- nerves (neurotransmitters) - fast action, governing response
- hormones - slower action, mainly metabolism, growth, differentiation and reproduction
list the similarities between the endocrine and the nervous systems?
- regulate cells and tissues
- act through receptors
- functional overlap between some hormones and neurotransmitters
- excitatory/inhibitory
describe a hormone?
- 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
name and describe the types of humeral signalisation?
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
describe the types of hormone transport?
- freely in the blood - catecholamines and most peptides
* specific transport globulins (from liver) - steroids
what is the name for a signal molecule?
a ligand
state the ways hormones are inactivated?
- target tissue uptake
- metabolic degradation (plasma, liver, kidney)
- excretion in urine
- decreased by transporter binding - low for proteins
- reabsorption and degradation in kidneys
name and give an example of the types of hormone classification?
- protein and polypeptide - e.g. growth
- amine - e.g. epinephrine
- steroid - e.g. cortisol
describe the rhythms which regulate hormone release?
- circadian - light/dark endogenous rhythm cells and suprwahiasmatic nucleus of hypothalamus
- e.g. melatonin and cortisol
- monthly
- seasonal - day length, atavistic
- developmental - puberty, menopause
other than rhythms, describe another method of regulating hormone release?
pulsations/ oscillations - gonadotropins = sensitive target tissue and up-regulate receptors - improved responses
describe the functions of the hypothalamus ?
- 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
name some examples of releasing and inhibitory hypophysiotrophic hormones released by the hypothalamus?
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)
name and describe some anterior pituitary hormones?
*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
