Lab 3 Review: Endocrine System Flashcards
humoral stimuli
Changes in blood levels of ions and nutrients
directly stimulates secretion of hormones
Neural stimuli
Nerve fibers stimulate hormone release
Hormonal stimuli
Hormones stimulate other endocrine organs to
release their hormones (tropic effect)
hypophysis synonym
pituitary gland
pituitary gland synonym
hypophysis
neurohypophysis synonym
Posterior pituitary
Posterior pituitary
-neurohypophysis
*Extension of the hypothalamus
*Contains the terminal ends of the neuroendocrine cells
*Releases (does not synthesize) 2 neurohormones…ADH and oxytocin, which are made in the hypothalamus
Anterior pituitary
(adenohypophysis)
*Glandular epithelial tissue
*Synthesizes and releases ~6 hormones
*Regulated by hypothalamic releasing or
inhibiting hormones
*Has vascular connections to hypothalamus
adenohypophesis synonym
anterior pituitary
Anterior pituitary hormones
- Growth hormone (GH)
- Prolactin (PRL)
- Thyroid-stimulating hormone (TSH) or thyrotropin
- Adrenocorticotropic hormone (ACTH)
- Follicle-stimulating hormone (FSH)
- Luteinizing hormone (LH)
FLATPiG
Posterior Pituitary Hormones
- Oxytocin
- Anti-diuretic hormone (ADH) or vasopressin
How are anterior pituitary glands released?
Hormonal/glandular, not neural:
-When appropriately stimulated, hypothalamic neurons secrete releasing and inhibiting hormones into the hypophyseal portal system.
-Hypothalamic hormones travel through the hypophyseal portal system to the anterior pituitary where they stimulate or inhibit release of hormones from the anterior pituitary (hormones synthesized in the anterior pituitary)
What actions stimulate the release of oxytocin, and what does oxytocin do in response?
-posterior pituitary/neurohyphophesis
-sense receptors in nipples during breastfeeding: triggers milk ejection in lactation
-stretch receptors in cervix/uterus during childbirth: stimulates contractions
What actions stimulate the release of ADH (vasopressin), and what does ADH do in response?
-posterior pituitary/neurohyphophesis
-Released with activation of hypothalamic osmoreceptors when they sense high solute concentrations (Na+)
-in response: ADH inhibits urine formation in the renal tubules (reabsorption of water, no pee), and this fluid retention offsets high osmolarity
What controls growth hormone (GH) release?
-anterior pit/adenohypophesis
-growth hormone releasing hormone (GHRH) and growth hormone inhibiting hormone (GHIH/somatostatin “body stasis”): neurohormones released by the hypothalamus
Function/response of growth hormone release:
-Stimulates growth of all cells: Main targets are liver, bone and skeletal muscle
-metabolic effects: Promotes breakdown of fat stores
and stored glucose for use as fuel (use fat to grow)
somatostatin
Growth hormone inhibiting hormone (“body stasis”)
imbalances of growth hormone
gigantism and acromegaly
what controls the release of thyroid stimulating hormone (TSH)/thyrotropin
-anterior pituitary
-Released in response to thyrotropin-releasing
hormone (TRH) from the hypothalamus
function of TSH
- Stimulates the normal development and secretory
activity of the thyroid (tropic) - Release of thyroid hormones
(T3/T4)
-(think: hypothalamus makes thyrotropin-releasing hormone, which makes AP gland make and release TSH, which acts on thyroid gland, which then releases T3 and T4): tropic cascade
what controls the release of adrenocorticotropic hormone (ACTH)
- Released in response to hypothalamic corticotropin releasing hormone (CRH) in a daily rhythm
- Also, released in response to acute stress
CRH
-corticotropin-releasing hormone: produced in hypothalamus and stimulates release of ACTH
-produced in a daily rhythm and in response to acute stress
function of ACTH
-ACTH stimulates the adrenal cortex to release glucocorticoids (cortisol)
– Tropic effect
-glucocorticoids: sugar and stress
gonadotropin hormones
LH and FSH
what controls the release of gonadotropins?
- Release triggered by hypothalamic gonadotropin releasing hormone (GnRH) during and after puberty
function of gonadotropins:
- Stimulates ovarian follicle maturation and sperm production: Necessary for reproduction (FSH)
- Promotes production of sex hormones (LH)
what controls the release of prolactin?
- Release is primarily controlled by hypothalamic
prolactin-inhibiting hormone (PIH)
-Also known as dopamine (I’m happy and chilled out and baby is full so i can stop)
what is the function of prolactin?
-Stimulates milk production by mammary glands: Lactation
thyroid gland (location, types of cells that make it, what does it release)
-Bi-lobed endocrine gland located in the anterior neck,
on the trachea just inferior to the larynx
-consists of two types of endocrine cells:
* Follicle cells that produce thyroglobulin
* Parafollicular cells that produce the hormone
calcitonin
-releases thyroid hormones t3 and t4, which are derived from iodinated thyroglobulin, which is produced by follicle cells
follicle cells
one of two cells found in thyroid gland, produce thyroglobulin, which are used to make thyroid hormones t3 and t4 in the presence of iodine
parafollicular cells
one of two cells found in thyroid gland, produce calcitonin
thyroid hormone: source and function
-made from thyroglobulin and iodine (t3 and t4), the former of which is produced by follicle cells in the thyroid gland
-increases metabolic rate and heat production
-plays a role in: heart function, tissue growth, development of skeletal and nervous systems, reproductive capabilities
Grave’s disease
hyperthyroidism: too much thyroid hormone production. bulging eyes (exophthalmos), thyroid enlargement, heat intolerance, anxiety
calcitonin
-produced by parafollicular cells (c cells) of the thyroid gland
-“tones down blood calcium” and stimulates uptake of calcium in bones, and tells osteoclasts to stop their activity
hypothyroidism
low thyroid hormone, usually from lack of iodine. creates a goiter in the throat/thyroid area.
parathyroid glands (location, types of cells that make it, function)
- 4 – 8 glands embedded in the posterior aspect of the thyroid
- Contain oxyphil (unknown) and chief cells (secrete PTH, which increases blood Ca)
function and source of PTH
-parathyroid hormone
-secreted by chief cells of parathyroid gland
-the main regulator of Ca2+ homeostasis (Ca is critical for life processes including neuronal transmission and
muscle contraction)
-PTH is released in response to falling levels of blood Ca2+; acts to increase blood Ca (opposite of calcitonin): stimulates breakdown of bone matrix, enhances reabsorption of Ca by the kidneys, promotes activation of vitamin D by the kidneys which increases absorption of Ca by intestines
Adrenal medulla
-inner core of the adrenal gland
-nervous tissue; part of the sympathetic nervous system
-Synthesizes and secrete catecholamines (epinephrine (80%) and norepinephrine (20%)) in response to stress: fight or flight
-sympathetic nervous system
catecholamines
-epinephrine (80%) and norepinephrine (20%). synthesized
-released by the adrenal medulla –nervous tissue (think acetocholamine, made by nerves)
-Release triggered by activation of the sympathetic
nervous system (SNS): Fight or flight
-Promotes survival processes: Metabolic rate, Bronchial dilation, Glycogen breakdown, Cardiac muscle contraction, Directs blood flow to critical organs (e.g. brain, heart)
Adrenal cortex
-outer three layers of the adrenal gland
-glandular tissue
-synthesizes and secretes corticosteroids
*hormones and functions of the different zones of the adrenal cortex
what are the three zones of the adrenal cortex?
Go For a Run:
zona glomerulosa: mineralocorticoids (salt)
zona fasciculata: glucocorticoids (sugar)
zona reticularis: androgens (sex)
*imbalances of adrenal hormones
- Hypersecretion of mineralocorticoids
– Aldosteronism - Hyposecretion of glucocorticoids
– Addison’s disease - Hypersecretion of glucocorticoids
– Cushing’s syndrome
cells of the pancreas
exocrine (acinar cells for digestion) and endocrine (islets of langerhans cells: alpha and beta cells)
-alpha cells: produce glucagon
-beta cells: produce insulin
alpha cells
-part of islets of langerhans in pancreas
-produce glucagon
beta cells
-part of islets of langerhans in pancreas
-produce insulin
glucagon
-produced by alpha cells in pancreas
-acts on liver to increase blood glucose (“i’m hungry and faint, where oh where has glucagon!!”)
-Glycogenolysis—breakdown of glycogen to
glucose
-Gluconeogenesis—synthesis of glucose from
lactic acid and non-carbohydrates
insulin
-produced by beta cells in pancreas
-acts at skeletal muscle, liver and fat to ↓ blood glucose
-Inhibits glycogenolysis and gluconeogenesis
-Enhances membrane transport of glucose
into fat and muscle cells
*OGTT (glucose tolerance test)
100 vs 125 dm/ml etc
*glandular histology
