the endocrine system Flashcards
what is the endocrine system
it is a collection of endocrine glands and tissues found throughout the body that produce and secrete hormones
what does the endocrine system do with the nervous system
work together to maintain homeostasis, by responding to changes within the internal environment and influencing cellular activity
what is the definition of hormone
hormones are chemical signals released from endocrine glands into the bloodstream where they travel to target tissues, stimulating particular cellular actions
what are the three types of stimuli/ regulation for hormone release
humoral stimulus
neural stimulus
hormonal stimulus
what is the concentration of a hormone determined by
- the rate of hormone release from its endocrine gland
- the rate of inactivation and removal of the hormone from the blood
what is a half life
the time it takes for a hormones blood level to decrease by half. different hormones have different half lives
what is humeral stimulation
when the concentration of a solute in the blood moves out of its set point range, it triggers the release of a hormone. when the ion/ nutrient returns back to its set point range, it inhibits further release of the hormone (shuts off the hormone release)
what is neural stimulation
action potential in a nerve stimulates the release of a hormone. when nerve stimulation of an endocrine gland stops, it inhibits further release of that hormone
what is hormonal stimulation
a hormone from one gland stimulates the release of a hormone from another gland. when levels of the final hormone release rise, it inhibits the release of the initial hormone
what are the main endocrine glands of the body
pineal gland, hypothalamus, pituitary gland, thyroid gland, parathyroid gland, adrenal gland, pancreas, ovaries, testes
what is the hypothalamus
it is a neuroendocrine organ- a major component of the nervous system and also the control centre for the endocrine glands
anterior pituitary gland hormones (secretes hormones in response to hormonal stimulation from hypothalamus)
- growth hormone
- thyroid stimulating hormone
- ACTH
- prolactin
- luteinizing hormone and follicle stimulating hormone
- growth hormone- liver, skin, most body cells, bone- cell/ tissue growth
- thyroid stimulating gland- thyroid gland- stimulates production and release of TH
- ACTH- adrenal gland- production and release of cortisol
- prolactin- breasts- breast milk production
- lutenizing hormone and follicle stimulating hormone- gonads- stimulating sex cell production and sex hormone production secretion
posterior pituitary gland (secretes hormones made by the hypothalamus in response to neural stimuli)
- oxytocin
- ADH
- Oxytocin- breasts and uterus- breastmilk release and contractions
- ADH- kidneys- retain water/ reabsorption of water from kidneys back into the blood
thyroid gland
- thyroid hormone
- calcitonin
- thyroid gland (T3 and T4)- most body cells- increase cell metabolism (make ATP)
- calcitonin- bone- decreases the amount of calcium in the blood, stimulates osteoblasts
parathyroid gland
1. parathyroid hormone
parathyroid hormone- bones, kidneys and intestines- increases blood calcium levels, stimulate osteoclasts, increase reabsorption of calcium, increase calcium reabsorption from food
adrenal gland
- aldosterone
- cortisol
- adrenaline and noradrenaline
- aldosterone- kidneys- increasing sodium reabsorption and increases blood volume and blood pressure
- cortisol- most body cells, adipose tissue, skeletal muscle, liver- make energy and stores available for cellular use during stress
- adrenaline and noradrenaline- SNS effectors (heart, respiratory tract, blood vessels)- enhance the sympathetic nervous effects at those tissues
pancreas
- insulin
- glucagon
- insulin- liver, skeletal muscle, adipose tissue, most body cells- decrease blood glucose levels, most body cells take glucose from the blood to make ATP. liver and skeletal muscles remove glucose from the blood and store it. adipose tissue makes glucose and converts it to fat.
- glucagon- liver- increase blood glucose levels, release stored glucose back into the blood. also turns fat and protein into glucose and puts back into blood
gonads
- estrogen and testosterone
- progesterone
- estrogen and testosterone- reproductive structures, skin, connective tissue including bone, muscles- help reproductive structures grow and develop, help support and sustain their ongoing functions. skin, CT etc causes secondary sex characteristics
- progesterone- uterus, breasts, cervix- stimulates breast development, stimulates cyclical changes in the uterus
what are the 2 sets of hormones the hypothalamus secretes
- regulatory hormones that control the release of hormones produced by the anterior pituitary gland
- two hormones that are transmitted to, stored in and released from the posterior pituitary gland
what does the pineal gland do
it produces melatonin which is involved in the regulation of circadian rhythms of the body, including sleep/ wake cycles, mood and eating patterns. it may also be involved in inhibiting reproductive function during childhood
do hormones work slower than nerve signals
yes
characteristics of the anterior pituitary gland
- releases 6 hormones
- produces own hormones
- hormonal stimuli causes hormone release
characteristics of posterior pituitary gland
- releases two hormones
- neural stimuli causes hormone release
- stores hypothalamic hormones
what are the 2 regions of the adrenal gland
- the adrenal cortex- produces and secretes numerous hormones known as corticosteroids (mineralocorticoids, glucocorticoids, gonadocorticoids)
- the adrenal medulla- innervated by sympathetic neurons of the autonomic nervous system and synthesizes and secretes 2 catecholamines in response to neural stimulation (adrenaline and noradrenaline)
effects of glucagon (pancreas)
- stimulates gluconeogenesis
- stimulates glycogenolysis
- increases blood glucose levels
- target; liver
effects of insulin (pancreas)
- stimulates glycogenesis
- stimulates cellular uptake of glucose
- stimulates cellular uptake of amino acids
- decreases blood glucose levels
- targets most body cells
- stimulates lipogenesis
what are some other hormone secreting tissues in the body
the heart, adipose tissue, nerves, stomach, small intestine, thymus, kidneys, bone, skeletal muscle, skin
