Endocrine Physiology Flashcards
what are the two types of glands?
endocrine and exocrine
what do exocrine glands secrete?
substances to the outside (e.g digestive glands, sweat glands)
Do ducts allow secretion?
YEAH
what do endocrine glands secrete?
hormones to the blood (e.g thyroid, gonads, pituitary
Are ducts required in endocrine glands?
no
nonpolar hormones?
- cant dissolve in plasma -> carrier proteins
- pass through PM DIRECTLY into cell
what are examples of nonpolar hormones?
steroids and thyroid hormones
where are steroids derived from?
cholestorol
where are thyroid hormones derived from?
tyrosine
polar hormones?
- dissolve easily in plasma
- can’t pass through PM, must use receptor
What are examples of polar hormones?
amines (melatonin), polypeptides (insulin), proteins (growth hormones)and glycoproteins (LH)
what is a pituitary gland also called?
hypophysis
where is the pituitary gland located?
directly below hypothalamus (connected by infundibulum)
how many glands are in the pituitary gland?
2
what are the names of the 2 pituitary glands?
anterior and posterior
what is AP (or adenohypophysis) derived from?
oral epithelium
what is the connection between AP and the hypothalamus?
there is no neural connection between them
what is PP (or neurohypophysis) derived from?
brain
what is the connection between PP and the hypothalamus?
axons extend from the hypothalamus
are hormones from PP secreted or produced?
secreted
what is an example of an antidiuretic hormone (ADH)?
vasopressin
what does the stimulus equal in an ADH?
high osmolality (dehydration), increased blood pressure
what is the target of ADH?
kidney, arterioles
what is the action of ADH?
H2O retention, vasocontriction
what is an example of a stimulus for Oxytocin?
baby sickling
what is the target for oxytocin?
- uterine smooth muscle -> contraction at parturition
- mammary alveoli -> milk ejection (let down)
- brain -> maternal bonding
- men = sperm transport
what are the two hormones secreted by PP?
antidiuretic hormone and oxytocin
what does the AP do?
produces and releases hormones
what kind of hormones does the AP produce/release?
growth hormones, thyroid stimulation hormone, and adrenocorticotropic hormone
growth hormones (GH)
- i.e somatotropin
- promotes tissue and organ growth, synthesis
thyroid stimulating hormone (TSH)
- i.e thyrotropin
- stimulates the thyroid to secrete thyroxine (T4) and triiodothyronine (T3)
adrenocorticotropic hormone (ACTH)
- i.e corticotropin
- stimulates the adrenal gland to release steroids (e.g cortisol)
follicle-stimulating hormone (FSH)
- i.e. folliculotropin
- women -> stimulates growth of ovarian follicles
- males -> stimulates production of sperm in testes
Luteinizing hormone (LH)
- i.e. luteotropin
- women -> stimulates ovulation and formation of corpus luteum in ovaries
- men -> stimulates interstitial Leydig cells of testes to secrete testosterone
prolactin (PRL)
- women -> stimulates milk production by mammary glands
- roles in reproduction and kidneys of men and women
what is the system that controls the AP?
hypothalamo- hypophyseal portal system
what does the hypothalamus secrete?
releasing hormones
corticotropin-releasing hormone (CRH)
AP-> ACTH
thyrotropin-releasing hormone (TRH)
AP -> TSH
gonadotropin-releasing hormone (GnRH)
AP -> FSH & LH
growth hormone-releasing hormone (GHRH)
AP -> GH
do all or some hypothalamic hormones inhibit AP?
some
what does hypothalamic control of AP apply to?
AP hormones that DON’T stimulate hormone production by other glands
somatostatin of hypothalamic control of AP
AP blocks production of GH
prolactin-inhibiting hormone (hypothalamic control of AP) (PIH)
AP blocks production of PRL
control of AP hormone secretion
- negative feedback inhibition
- eventually, reach hypothalamus and AP
- inhibit the production of releasing and stimulating hormones
- anabolic steroid abuse
what are hormones produced in control of AP hormone secretion?
by target organ circulating in the blood
what kind of disorders can be found in endocrine?
primary and secondary
primary endocrine disorders
- the dysfunction is at all the levels of the final gland (e.g. thyroid and adrenal)
- negative feedback functions on AP
secondary endocrine disorders
- the dysfunction is at the level of the AP (tumor is the most likely cause)
- negative feedback does NOT function
what are the two parts of an adrenal gland?
adrenal medulla and adrenal cortex
adrenal medulla has what type of control?
sympathetic
what does the adrenal medulla produce?
epinephrine (& norepinephrine)
what does the adrenal medulla promote?
fight or flight
what kind of stress response does the adrenal medulla have?
a quick response
what does the adrenal medulla dilate?
airways
what does the adrenal medulla stimulate?
glycogenolysis
what is the adrenal cortex controlled by?
ACTH from AP
what are glucocorticoids in the adrenal cortex?
- high blood glucose (glycogenolysis & gluconeogenesis)
- promote breakdown of AA
what weakness does the adrenal cortex have?
weak androgens
what type of response does the adrenal cortex have?
slow response
what is the first stage of the general syndrome (GAS)?
alarm reaction -> adrenal gland activated
what is the second stage of GAS?
stage of resistance -> readjustment occurs
what is the possible third stage of GAS?
stage of exhaustion -> sickness or death (readjustment didn’t work)
what are two common adrenal gland disorders?
cushing’s syndrome and addison’s disease
what is Cushing’s syndrome?
excessively high corticosteroids in blood
what is the cause of CS?
tumor of anterior pituitary or adrenal cortex
what are the symptoms of CS?
changes in carb & protein metabolism, hyperglycemia, hypertension, muscular weakness, pully appearance (buffalo hump or moon face)
what is the treatment of CS?
tumor removal
what is Addison’s disease?
inadequate secretion of glucocorticoids and mineralocorticoids
what is the cause of Addison’s disease?
damage to adrenal cortex due to autoimmune disease, infection, use of anticoagulants, tumor
what are the symptoms of AD?
hypoglycemia, Na+ & K+ imbalance, dehydration, hypotension, weight loss, weakness
what is the treatment for AD?
corticosteriods
what does the thyroid gland produce and secrete?
two nonpolar hormones
- thyroxine (T4) (carrier protein = thyroxine binding globulin TBG)
- triiodothyronine
what does T4 lose at the target cell through the membrane?
TBG
what does the target cell convert T4 into?
T3
when T3 uses cytoplasmic protein “stepping stones” what happens next?
nuclear receptor into gene transcription
what is required for proper growth/development of infants?
T3/T4
what is T3/T4 particularly important to?
CNS
what is cretinism?
severe mental disability caused by inadequate T4
what is cretinism treated with?
thyroxine
what does T3/T4 stimulate?
cell respiration
effects of T3/T4 in cell respiration?
- helps set the BMR
- extremely important for metabolism
what are two thyroid disorders?
hypothyroidism and hyperthyroidism
what is hypothyroidism?
low T3/T4 levels
what happens when T4/T3 levels are low?
high TSH levels giving no feedback which raises the stimulation of thyroid and that causes enlargement of thyroid (goiter)
what are the possible causes of hypothyroidism?
- low dietary iodine (iodized salt)
- autoimmune attack (Hashimoto’s thyroiditis)
what are symptoms of hypothyroidism?
- lethargy
- intolerance to cold
- absent perspiration
- slow pulse
- coarse, dry skin
- increased body weight
what is the treatment to hypothyroidism?
oral thyroxine (levothyroxin)
what is hyperthyroidism?
high/excessive T4/T3
what is the most common hyperthyroidism disease?
grave’s disease
what is grave’s disease?
an autoimmune disease where the immune system produces antibodies to the thyroid that cause it to grow, and when the thyroid tissue increase so does the T3/T4 levels
does negative feedback work in grave’s disease?
no, the antibodies are continuously stimulating
what are the symptoms of grave’s disease?
- impaired sleep
- intolerance to heat
- excessive perspiration
- rapid pulse
- loss of body weight
what are treatments for grave’s disease?
- anti-thyroid drug
- radioactive iodine
- thyroidectomy
what do parathyroid glands produce & secrete?
parathyroid hormone (PTH)
how do parathyroid glands regulate BLOOD CALCIUM?
reflects absorption from diet, deposition in bone and resorption from bone
what are three parts of endocrine pancreas?
islets of Langerhans, glucagon, and insulin
what is glucagon produced by?
alpha cells
what is glucagon stimulated by?
low blood glucose (inhibited by high blood glucose)
what does glucagon promote?
- glycogenolysis (liver
- gluconeogensis (liver)
- lipolysis (adipose)
- ketogenesis (multiple tissues)
what is insulin produced by?
beta cells
what is insulin stimulated by?
high blood glucose (inhibited by low blood glucose)
what promotes insulin?
movement of glucose into liver, muscles (glycogen), adipose tissue (triglycerides)
type I diabetes
- “childhood-onset diabetes”
- autoimmune disease
type II diabetes caused by?
“adult-onset diabetes”
- generally caused by poor diet (high fat & sugar) and lack of exercise
what is insulin resistance in type II diabetes?
decreased response to insulin in tissue, which means more insulin is required (also called insulin insensitivity, glucose tolerance)
what is treatment for type I diabetes?
insulin injections
what is treatment for type II diabetes?
diet and exercise, oral drugs
what does the pineal gland secrete?
melatonin upon stimulation by SCN of the hypothalamus
what does the pineal gland regulate?
circadian rhythms
what does adipose tissue a huge producer of?
hormones and adipokines
what is adipose tissue a major player in?
satiety, hunger, obesity
what is Leptin?
hormone that induces satiety (feeling full)
what happens if you have more adipose?
you have more leptin and feel less hungry
what is resistin?
hormone involved in development of insulin resistance
