Chapter 16: Endocrine System Flashcards
Hormones that are important for growth & Growth disorders
Anterior Pituitary Hormone: GH (somatotropin) releases growth hormones throughout the day and especially during sleep
Main function of GH is to regulate and control the growth of target tissues
Insulin-like growth factor: triggers rapid protein synthesis and cell division
Disorders: gigantism, acromegaly (large extremities),and dwarfism
Function of hormones
interact with target cells in order to:
*maintain fluid, electrolyte & acid base homeostasis
*promote growth
*regulate metabolic reactions
Types of chemical signals
Endocrine: Secretes hormones via blood to DISTANT cells
Paracrine: Tissue cell, secretes chemicals via ECF to NEARBY cell
Autocrine: specialized cell, Secretes chemicals via ECF to SAME cell
Up regulation
Cells produce more hormone receptors if a hormone declines increasing the sensitivity to that hormone
Down regulation
Prolonged exposure to a high level organ can decrease hormone receptors
Classes of hormones
Amino Acid Hormones: consists of 1 or more AA; hydropphilic binding to plasma membrane receptors
Steroid hormones: derived from cholesterol; hydrophobic bind to receptor in cytosol or nucleus
target cells
hormones that are able to effect only particular cells that bind to protein receptors
negative feedback loop: regulation of hormone secretion
stim: regulated variable deviates from normal range
Receptor: Receptors on endocrine cells detect deviation
Control center: The stimulated control center increases or decreases its secretion of a particular hormone
Effector: Hormone triggers a response in its target cells that moves condition toward normal range
Hypothalamus
small anterior inferior portion of the diencephalon connected to the pituitary gland by a stalk (inundibulum)
Pituitary gland (structure)
composed of
anterior pit (adenohypophysis): composed of hormone secreting glandular epithelium
Posterior pit: nervous tissue
hormones made in the posterior pituitary
no hormones of its own but …
Oxytocin and anti-dieuretic are produced in the hypothalamus and stored and released in the posterior pit.
Anti diuretic Hormone(ADH)
Neurohormone that controls water balance
*Increases the amount of H20 retained by the kidneys and increases amount of water in body
Diabetes insipidus
diseased cause by abnormal lack of ADH; body is unable to conserve water
signs: extreme thirst and dehydration
Oxytocin
supporting reproduction and milk release
Hypothalamus and Anterior pituitary hormones
The hypothalamus produces and releases hormones that either stimulate or inhbit the release of hormones from the anterior pit.
Anterior Pituitary hormones that effect other glands :
Thyroid-Stimulating hormone (TSH) :
TSH release is stimulated by thyrotroponin-releasing hormone (TRH)
Anterior Pituitary hormones that effect other glands : Adrenocorticotropic (ACTH)
stimulates the development of adrenal glands and stimulated by CRH
Anterior Pituitary hormones that effect other glands: Prolactin (PRL)
stimulates the growth of mammary gland, (milk production)
Luteinizing & follicle stimulating hormone male gonadtropin(LH)
Stimulates the production of testosterone under the direction of (GnRH)
Luteinizing & follicle stimulating hormone hormone female gonadtropin(LH)
Stimulates the production of estrogen and progesterone under the direction of (GnRH)
Thyroid gland
secretes thyroid hormones and calcitonin
composed of thyroid follicles, colloid (stores iodine atoms), and parafollicular cells (produce calcitonin)
Parathyroid glands
secrete parathyroid hormones from chief cells
Parathyroid hormone
major factor in maintenence of blood calcium ion concentration
PTH is secreted in response to declining calcium ion levels in blood. goal is to maintain homeostasis and keep these levels on a normal range
In declining calcium ion levels PTH triggers the release of calcium ions from bone and increase the absorption from small intestine and the reabsorption from fluid from kidneys
Calcitonin
released when the the calcium ion level in blood INCREASES above normal
important in bone homeostasis
osteoclast activity is inhibited
Thyroid hormone
consists of amino acid core bound to T3 and T4 iodine atoms
Effects:
*regulation of metabolic rate and thermoregulation
*growth and development
* Synergism with sympathetic NS
T3 & T4
apart of thyroid hormone , enter target cell of nucleus and bind with receptors that either activate or inhibit specific gene transcription
thyroid hormone production
iodide ions and thyroglobulin are secreted into the colloid
iodide ions are converted to iodine atoms that attach to thyroglobulin
this then enters follicle cell and converted to T3 T4
T3 T4 then released into the bloodstream
hormonal responses to stress
hypothalamic-hypophyesal portal system
a specialized blood supply that allows both hypothalamus and pit to deliver their hormones to their target cells
Adrenal Glands
located at the superior end of each kidney and produce calc. and steroid hormones
adrenal cortex
Endocrine gland
adrenal medulla
neuroendocrine organ that secretes neurohormones
hormones of the adrenal medulla
consists of chromaffin cells and secrete epinephrine and norepinephrine
epinephrine (as it pertains to the adrenal medulla)
Increate heart rate
constrict blood vessels
supplying organs
hormones that have an impact on blood glucose
thyroid
growth
cortisol
Aldosterone
regulates blood pressure and blood flow through RAAS
Glucocorticoids
help mediate the bodys response to stress
Cortisol is the most important
cortisol
regulates blood glucose levels, anti inflammatory levels that decrease certain leukeocytes, release of fatty acids from adipocytes
regulation of cortisol
involves the HPA axis and control mechanism utilizing CRH and ACTH
cortisol disorders
over secretion of cort; cushings syndromea
adrenal insufficiency
Addisons disease renders the individual susceptible to adrenal crisis
Main hormones that maintain blood glucose level
Insulin and glucagon
pancreatic islets
small rounded islands populated by endocrine cells that secrete hormones in the bloodstream
Contains:
* Alpha cells: secrete glucagon
* beta: secrete insulin
*delta: secrete somatostatin
glucagon
produced and secreted from Alpha cells in panc. islets
promotes reactions that increase glucose level
glycogenolysis: dreakdown of glycconolgen
Gluconeogensis: Formation of glucose n the liver
Insulin
Primary antagonist of glucagon, produced and secreted form beta cells and promotes the uptake and storage of ingested nutrients into target cells
hypoglycemia
blood glucose levels too low, elevated insulin levels (weakness, dizziness, rapid breathing)
hyperglycemia
blood glucose levels too high, decresase insulin levels
Blood glucose regulation
Negative feedback
when glucose level increases beta cells of the pancreas detect the change and increase insulin secretion
location of hormone receptors
nucleus, cytoplasm or target cells membrane
g proteins
pineal gland
secretes melatonin , sleep wake cycle
the gonads: sex hormones
what are the effects of testosterone ?
stimulate bone growth, increase muscle mass,
The ovaries: Estrogen and progesterone
breasts, regulates menstrual
progesterone: helps prepare for pregnancy
Adipose : leptin
protein hormone that helps induce satiety (fullness)
