unit one endocrine system Flashcards
what does the endocrine system do?
it acts with the nervous system to coordinate and integrate activity of the body cells via hormones
endocrinology
study of hormones and endocrine organs
what does the endocrine system control and integrate?
- reproduction
- growth and development
- maintains electrolyte, water, and nutrient balance of blood
- regulation of cellular metabolism and energy balance
- mobilization of body defenses
what is the main difference between exocrine and endocrine glands?
endocrine glands lack ducts
what organs and glands are included in the endocrine system?
- pituitary
- hypothalamus
- thyroid
- parathyroid
- adrenal
- pineal gland
- pancreas
- gonads
- placenta
hormones
long-distance chemical signals
autocrines
same cells that secrete them
paracrines
cells other than those that secrete them
classes of hormones?
- amino acid-based hormones, water soluble
- steroids, lipid soluble
target cells
anything that has a receptor for that hormone
Characteristics of water-soluble hormones
- must have a receptor because that can’t pass the plasma membrane
- second messangers, cAMP and PIP2 calcium
Characteristics of lipid soluble hormones
- can act on receptors that directly activate the gene
steps for Cyclic AMP?
- bind to receptor
- activate a G protein
- G protein activates adenylate cyclase
- adenylate cyclase converts ATP to cAMP
- cAMP activates protein kinases
- phosphorylated proteins are activated or inactivated
- cAMP degenerates phosphodiesterase
steps for PIP2 calcium?
- protein G activates phospholipase C
- phospholipase splits PIP2 into diacylglycerol (DAG) or inositol triphosphate (IP3)
- calcium ions act as another messenger
lipid soluble steps?
- receptor hormone complex enters nucleus and binds to DNA
2. initiates DNA transcription
what the the three different endocrine gland stimuli and what are they associated with?
- humoral- blood
- neural- nervous system
- hormonal- 1 can release another
what three factors do target cell activation depend on?
- blood levels of hormone- up and down regulation
- relative number of receptors on or in the target cells
- affinity (strength) of binding
concentration of circulating hormone reflects?
- rate of release
2. speed at which it is inactivated and removed from body
what are the three different types of hormone interactions and how do they work?
- synergistic- together
- permissive- 1 sets of for the next hormone
- antagonistic- against each other
what does cell response depend on?
the amount of hormone and the combination of all hormones
when do tissues respond?
when hormone concentrations are at a certain normal level
anterior lobe
produces and secretes own hormones
regulated by hypothalamus and negative feedback
posterior lobe
stores and secretes hotness produced by the hypothalamus
what is sent from the anterior lobe
the anterior pituitary is controlled via releasing and inhibiting hormones transported through the?
hypothalamo-hypophyseal portal system
what does corticotropin- releasing hormone (CRH) stimulate?
adrenocorticotropic hormone (ACTH)
what does Thyrotropin-releasing hormone (TRH) stimulate?
thyroid stimulating hormone (TSH)
what does Gonadotropin-releasing hormone (GnRH) stimulate?
- follicle-stimulating hormone (FSH)
2. luteinizing hormone (LH)
what does prolactin-inhibiting hormone (PIH) inhibit?
prolactin
what does growth hormone releasing hormone (GHRH) stimulate?
growth hormone
tropic/trophic hormones
stimulate hormone secretion in other glands (growth)
growth hormone (GH)
promotes amino acid uptake and protein synthesis, causes growth
thyroid stimulating hormone (TSH)
stimulates thyroid to produce and secrete T3 and T4
adrenocorticotropic hormone (ACTH)
stimulates the adrenal cortex to secrete glucocorticoids
follicle stimulating hormone (FSH)
stimulate growth of ovarian follicles and sperm in testes
luteinizing hormone (LH)
stimulates ovulation and conversion of an ovulated ovarian follicle into the corpus lute or secretion of testosterone from the testes
prolactin (PRL)
milk production
anti-diuretic hormone (ADH)
stimulates water retention in the kidneys
oxytocin
stimulates contraction of the uterus and mammary glands
diabetes insipidus
rare disorder that causes a water imbalance within the body, by head trauma
-ADH deficiency due to damage to hypothalamus or posterior pituitary
symptoms of diabetes insipidus
extreme thirst and large urine volumes
what does the thyroid gland look like?
- hollow spaces called thyroid follicles lined with epithelium composed of follicular cells
- inferior of the follicles are filled with colloid
- outside of the follicles are parafollicular cells
- T3 and T4 which are which are follicles and colloid are the big bubbles
- calcitonin which is parafollicular cells are the smaller ell structures
thyroid hormone synthesis steps
- thyroglobulin is synthesized and discharged
- iodide is absorbed and released
- converting to iodine
- iodine is attached to tyrosine creating monoiodotyrosine or diiodotyrosine
- they link together creating T3 or T4
- colloid is enclosed by follicular cells
- lysosomal enzymes cleave t3 and T4
difference between T3 and T4
T4 is most abundant and T3 is more active
actions of T3 and T4
- protein synthesis
- promotes maturation of nervous system
- increase cellular respiration
- elevates basal metabolic rate + heat = calorigenic effect
hypothyroidism
- iodine deficiency
- low metabolic rate, weight gain
- cant produce T3 and T4 but it tells thyroid to so the thyroid gets bigger
hyperthyroidism
- autoimmune
- weight loss, exophthalmos
- too much thyroid
- TSH is produced by immune system and not anterior pituitary
what is calcitonin produced by?
parafollicular cells
actions of calcitonin
- inhibits osteoclasts, put more calcium
- excretion of calcium
- absorption of calcium
- lowers blood calcium levels
actions of PTH
- stimulates osteoclasts, digest bone and calcium to blood
- excretion of calcium, stop release
- absorption of calcium, bring more
- increase in blood calcium levels
adrenal cortex
secretes corticosteroids (mineral, gluto and steroid) in response to ACTH
adrenal medulla
secretes epinephrine and norepinephrine ( fight or flight)
mineralocorticoids
regulate Na+ and K+
ex: aldosterone
aldosterone
Na+ reabsorption by kidneys and K+ elimination by kidneys
results in increased blood volume and pressure
glucocorticoids
regulate glucose metabolism
regulate immune system
ex: cortisol
cortisol
release during stress
hypersecretion causes?
Cushing’s disease
sex steroids
weak androgens
what does insulin do?
binding to tyrosine kinase enzyme receptor trigger cells to increase glucose uptake
diabetes mellitus
frequent urination
fasting blood glucose test under 126
type 1 diabetes
- attacking B cells
- cant produce insulin and can’t get to tissues
type 2 diabetes
- lifestyle
- your body cant keep up
- cant filter glucose to is pulls water
gestational diabetes
-insufficent insulin
what are the there signs of diabetes?
- polyuria- urine
- polydipsia- thirst
- polyphagia- hunger
pancreas
has both exocrine and endocrine cells
glucagon
-produced by alpha cells
-increases blood glucose
glycogenolysis
gluconeogenisis
insulin
- produced by betacells
- decreases blood glucose
what are the three stages of General adaption syndrome
- alarm reaction
- resistance
- exhaustion
