Exam 5 - Endocrinology Flashcards
What are gap junctions?
Pores in cell membrane allow signaling molecules, nutrients, and electrolytes to move from cell to cell
What are neurotransmitters?
Released from neurons to travel across synaptic cleft to second cell
What are Paracrines?
Secreted into tissue fluids to affect nearby cells
What are hormones?
Chemical messengers that ravel in the bloodstream to other tissues and organs
What cells are affected by hormones?
Only cells with receptors that respond to hormones
What is the endocrine system?
Glands, tissues, and cells that secrete hormones
What is endocrine glands?
Organs that are traditional sources of hormones
What are hormones?
Chemical messengers that are transported by the bloodstream and stimulate physiological responses in cells of other tissue or organ
How does the nervous system react and stop?
The nervous reacts quickly and stops quickly
How does the endocrine react and stop?
Reacts slowly and effects may continue for days or longer
How does the nervous system adapt to long-term stimuli?
Response declines (adapts quickly)
How does the endocrine system adapt to long-term stimuli?
Its responses persists (adapts slowly)
What is the area of effect of the nervous system?
Targeted and specific (one organ)
What is the area of effect of the endocrine system?
The general, widespread effects (many organs)
What are target organs or cells?
Those organs or cells that have receptors for a hormones and can respond to it
What chemical functions as both hormones and neurotransmitters?
Norepinephrine, dopamine, and antidiuretic hormone
How does the nervous system communitcate?
Electrical impulses and neurotransmitters
How does the endocrine system communicate?
Hormones
How does the nervous system send neurotransmitters?
It releases them at synapses at specific target cells
How does the endocrine system release hromones?
It releases them into bloodstream for general distribution throughout body
What is the hypothalamus shaped like and what is its function?
A flattened funnel; it regulates primitive functions
What is adenohypophysis?
The anterior pituitary
What is neurohypophysis?
Posterior pituitary
How is the pituitary gland connected to the hypothalamus?
A stalk called the infundibulum
How much does the anterior lobe consist of the pituitary?
3/4
How is the anterior lobe connected to the hypothalamus?
The hypophyseal portal system
What is ACTH?
Adrenocorticotropic hormone
Where is ACTH released?
Anterior pituitary
What is ADH?
Antidiuretic hormone
Where is ADH released?
Posterior pituitary
Where is CRH released?
Corticotropin-releasing hormone
Where is CRH released?
The hypothalamus
What hormone does CRH release and where?
Adrenocorticotropin hormone
What is EPO?
Erythropoietin
Where is EPO released?
Kidneys, liver
What is FSH?
Follicle-stimulating hormone
Where is FSH released?
Anterior Pituitary
What is GH?
Growth Hormone
Where is GH released?
Anterior Pituitary
What is GHRH?
Growth hormone-releasing hormone
Where is GHRH released?
Hypothalamus
What is GnRH?
Gonadotropin-releasing hormone
Where is GnRH released?
Hypothalamus
What is LH?
Luteinizing hormone
Where is LH released?
Anterior pituitary
What is OT?
Oxytocin
Where is OT released?
Posterior pituitary
What is PIH?
Prolactin-inhibiting hormone
Where is PIH released?
Hypothalamus
What is PRL?
Prolactin
Where is PRL released?
Anterior pituitary
What is TRH?
Thyrotropin-releasing hormone
Where is TRH released?
Hypothalamus
What is TSH?
Thyroid-stimulating hormone
Where is TSH released?
Anterior pituitary
How many hormones are produced in the hypothalamus? How many go to anterior and how many go to posterior?
8 hormones, 6 anterior and 2 posterior
What hormones are released by TRH?
TSH and PRL
What hormones are released by CRH?
ACTH
What hormones are released by GNRH?
FSH and LH
What hormones are released by GHRH?
GH
What does PIH do?
Inhibit secretion of prolactin
What does somatostatin do?
Inhibit secretion of growth hormone and thyroid-stimulating hormone
What are the two gonadotropin hormones that target gonads?
FSH (follicle-stimulating hormone) and LH (Luteinizing hormone)
What does FSH do?
Secretion of ovarian sex hormones, ovarian follicles, and sperm production
What does LH do?
Stimulates ovulation, stimulates corpus luteum to secrete progesterone, and stimulates testes to secrete testosterone
What does TSH do?
Stimulates secretion of thyroid hormone
What does ACTH do?
Stimulates adrenal cortex to secrete glucocorticoids
What does PRL do?
After birth, stimulates mammary glands to synthesize milk
What does GH do?
Stimulates mitosis and cellular differentiation
What does ADH do?
Increases water retention, reducing urine volume, and preventing dehydration. Can cause vasoconstriction
What does OT do?
It is released during sexual arousal and orgasm, also stimulates labor contractions during childbirth, stimulates flow of milk during lactation
What is negative feedback?
Increased target organ hormone levels inhibit release of hypothalamic and/or pituitary hormones
What is IGF_I?
Insulin-like growth factors
What does IGF-I do?
Prolongs the action of GH
How long is the half-life of GH with and without IGF-I?
It is originally 6 to 20 mins, with it its 20 hours
What does GH in the liver do?
It increases protein synthesis, Increases lipid metabolism, Increases carbohydrate metabolism, and helps electrolyte balance
Where is the pineal gland?
Attached to the roof of the third ventricle beneath the posterior end of the corpus callosum.
What does the pineal gland do?
Synthesizes melatonin from serotonin
What hormones does the thymus secrete?
Thymopoietin, thymosin, and thymulin
What do the hormones from the thymus do?
Stimulate development of other lymphatic organs and activity of T lymphocytes
What is important about the thyroid gland?
Largest gland that is purely endocrine
What are thyroid follicles?
Sacs that make up most of thyroid, contains protein-rich colloid
What are follicular cells?
Simple cuboidal epithelium that lines follicles
What hormones does the thyroid gland release?
Thyroxine, tetraiodothyronine, and triiodothyronine
What do the hormones released by the thyroid gland do?
They increase metabolic rate and growth hormone secretion. They contain parafollicular cells that secrete calcitonin
Why do the thyroid hormones secrete calcitonin?
They release it with right blood calcium, it stimulates blood formation in children
Where are the parathyroid glands?
Four glands embedded in posterior surface of thyroid gland
What hormones does the parathyroid gland secrete?
The parathyroid hormone
What does the PTH hormone do?
Increases blood calcium levels by synthesis of calcitriol and increases absorption of calcium.
Where are the adrenal glands?
Small glands that sit on top of each kidney
What are the two things that the adrenal glands do?
They are an endocrine gland and a ganglion of the sympathetic nervous system
What are the layers of the adrenal cortex?
Zona glomerulosa, zona fasciculata, and zona reticularis
What does the zona glomerulosa release and what does it do?
Mineralocorticoids so aldosterone that stimulates Na retention and K excretion
What does the zona fasciculata release and what does it do?
Glucocorticoids in response to ACTH, it regulate metabolism of glucose
What is the example of the glucocorticoid?
Cortisol and corticosterone that stimulate fat and protein catabolism
What is secreted by the zona fasciculata and zona reticularis?
Sex steroids. Androgens have a large role in prenatal male development (DHEA) and the formation of characteristics of puberty. Also, estradiol that is important after menopause
What of the parts of the pancreatic islets are exocrine and endocrine?
The pancreas is 99% exocrine but the end of its tail is the 1% endocrine
What is glucagon?
Secreted by A or alpha cells in the pancreas
What does glucagon do?
It is released between meals when blood glucose concentration is falling
How is insulin secreted?
By B or beta cells in the pancreas
What does insulin do?
It is secreted during and after meal when glucose and amino acid blood levels are rising
What is a lack of insulin called?
Diabetes mellitus
What are the exocrine products of the ovaries and testes?
Eggs and sperm
What are the endocrine products of ovaries and testes?
Gonadal hormones, mostly steroids
What are the ovarian hormones?
Estradiol, progesterone, and inhibin
What are the testicular hormones?
Testosterone, weaker androgens, estrogen, and inhibin
What secretes progesterone?
The corpus luteum after ovulation for 12 days
What secretes inhibin?
Follicle and corpus luteum
What are the functions of estradiol and progesterone?
Development of female reproductive system and regulates menstrual cycle
What does inhibin do?
Suppresses FSH secretion from anterior pituitary
Where is testosterone and other steroids released?
Interstitial cells between tubules
What does testosterone do?
Stimulates development of male reproductive system and sustains sperm production
Where is inhibin released?
Sustentacular cells
Why does inhibin limit FSH secretion in males?
To regulate sperm production
What is hyposecretion?
Inadequate hormone release
What does hypersecretion of GH do?
Acromegaly which is the thickening of bone, causes gigantism
What does hyposecretion of GH cause?
Dwarfism
What is hypoparathyroidism?
IT is a surgical excision during thyroid surgery; can kill the person do to decrease in blood calcium level
What is hyperparathyroidism?
Excess PTH secretion that causes parathyroid tumor, bones become soft
What is Diabetes mellitus?
Inaction of insulin, can cause polyuria, polydipsia, and polyphagia
What is used to treat type 1 diabetes mellitus?
Insulin injections
What is type 2 diabetes mellitus?
It is caused by insulin resistance
What is used to treat type 2?
Weight-loss and exercise
What is pathogenesis?
Cells cannot absorb glucose and rely on fat and proteins for energy needs
What is chronic pathology?
Chronic hyperglycemia which leads to neuropathy and cardiovascular damage