Endocrine: Thyroid and Adrenal Glands Flashcards
the ___ is one of the largest endocrine glands in the human body
thyroid
describe the structure of the thyroid gland
2 lateral lobes connected by a narrow region
the main hormones produced by the thyroid gland are ___ and ___
T3 (triiodothyronine) and T4 (thyroxine)
T3 and T4 affect almost every ___ in the body and regulates ___
cell; metabolic activate y
the thyroid gland secretes ___ which in important to calcium metabolism regulation
calcitonin
the production and secretion of hormones from the thyroid is tightly regulated by the ___ and ___
hypothalamus and pituitary
the thyroid is organized into structures called ___
follicles
each thyroid follicle is made of a monolayer of ___ and is filled with ___
epithelia cells; thick sticky colloid
what is the sticky substance within the thyroid follicle?
thyroglobulin
the monolayer of epithelial cells is essential to __
making of thyroid hormones
C cells or parafollicular cell of the thyroid are involved in the production of ___
calcitonin
there are ___ cells that line the cwppilalries that provide blood supply to follicles
endothelial
t/f the thyroid is essential for the normal maturation of nervous system
t
t/f the thyroid is essential to the normal growth (required for the GH synthesis and action)
t
t/f the thyroid maintains normal alertness and reflexes
t
t/f the thyroid determines the basal metabolic rate
t
to regulate basal metabolic rate, the thyroid gland can increase what 3 things?
- ATPase activity
- rate of ATP consumption
- fuel consumption to replace ATP
t/f the thyroid facilitates the sympathetic activity (permissive effects)
t
driven by ___, the follicles secrete thyroid hormones and increase their biosynthetic activities, up regulating the expression of the ____ transporter and the production of ___ (both essential to making T3 and T4)
TSH; I/Na, thyroglobulin
TSH binds to ___ receptors to activate 2 pathways (___ and ___) which in turn activates the ___ of genes involved in TH production including ___, ___ ad ___
adenyl cyclase and phospholipase C; transcription; Na/I symporter, thyrogobilun , and thyroid peroxidase
outline the steps of TH production
- follicles makes enzymes and thyroglobulin
- I is transported into colloid by N/I symporter
- enzymes add I to thyroglobulin to make T3 and T4
- thyroglobulin is taken back into the cell
- intracellular enzymes separate T3 and T4 from protein
- free T3 and T4 enter circulation
what enzyme helps add the iodine to the T3 and T4?
thyroid peroxidase
T3, T4 and Tg are taken up into thyroid cells by the process of ___
pinocytosis
how is Tg separated from T3 and T4?
lysosomes
thyroglobulin is a ___ protein used for the making of __and has 140___
large; TH; tyrosine
mon or di-iodinated ___ are coupled to each other to form T3 and T4, still attached to the ___ protein
tyrosine; thyroglobulin
incorporation of iodine at the indicated ___ is essential for TH function
positions
once released in the blood TH binds to the ___
thyroxin-binding globulin (90%)
what are the 3 transport proteins that carry TH?
- thyroxin-binding globuli
- transthyretin
- serum albumin
what is the function of TH carriers in the blood?
help TH reach target
once TH reaches the target cell and enters the cytoplasm, most T4 is converted to T3 by ___
5’/3’ monodeiodinase
T3 binding to TH receptor activates ___ and induce the ___ of many genes
thyroid response elements; transcription
90% of TH bound to receptor is T_
3
when TSH is low, there is a net __ of colloid and follicles are relatively ___ and __
accumulation; small and inactive
when TSH is high, the follicle cells become __ and __ shaped and there is a net ___ of colloid due to __. The blood flow to the follicle is ___
large and columnar; decrease; pinocytosis; increased
___ is the leading cause of hypothyroidism in the world
dietary iodine deficiency
what causes a loiter?
iodine deficiency and build of of TSh that stimulates growth in the region
hyperthyroidism can be due to __
Graves disease
in hypothyroidism due to low iodine there is ____ negative feedback and in hyperthyroidism due to Graves, there is ___ negative feedback
no; strong
hypothyroidism can be treated using __
T3/T4 replacements such as synthroid (T4) and cytomel (T3)
is synthroid (T4) or cytomel (T3) safer?
synthroid
what are 2 ways hyperthyroidism can be treated?
- prevent hormone making by inhibits peroxidase so iodine can’t be added
- block iodotyrosine coupling
the adrenal glands are ___shaped and made of an inner layer (___) and outer layer (___)
triangle; medulla; cortex
the outermost layer of the adrenal cortex contains ___ cells that secrete___ and the 2 inner layers (___ and ___) secrete __ and __
glomerulosa; aldosterone; fasciculata and reticularis ; cortisol and sex steroid s
the adrenal medulla contains ___ cells that secrete a variety of peptides such as ___ and a small amount of ___
chromatin; E and NE
the zone glomerulosa of the adrenal cortes secretes
mineralcorticoids
the zone fasciculata of the cortex secretes __
glucocorticoids
the sone reticularis secretes ___
androgens
the particular steroid secreted by different cell layers of the adrenal gland is determined by the expression of different ___ in different cell types
steroid metabolizing enzymes
there are no genes encoding steroid hormones, just genes encoding enzymes that metabolize __ and its derivatives
cholesterol
all of the hormones made by the adrenal cortex are derived form __
cholesterol
the adrenal cortex is controlled by an endocrine axis that provides a ___ response, allowing for both __ and __ hormonal adjustment
multilayered; gross and fine
the zone F and R are controlled by the __ and the zone G is controlled by __
endocrine axis; angiotensin 2
what are the major functions of the adrenal gland?
- mobilizing and increasing AA in blood and liver
- stimulating liver to convert AA to glucose (fuel for energy production)
- stimulating glycogen production in liver
- mobilizing and increasing FA in blood for energy
- counteracting inflammation and allergies
- preventing Na loss in urine to maintain BP
- maintaining resistance to stress
- maintaining mood
___ is the key regulator for metabolism and resistance to stress
cortisol
secretion of cortisol is controlled via a ___
typical negative feedback system
cortisol plays a central role in many parts of cell physiology, including ___, ___, __, __ and __
anti-inflammatory, protein breakdown, glucose formation, lipid breakdown , release of FA
does cortisol increase or decrease immune function?
decrease
cortisol has a ___ effect on the actions of other hormones, such as ___ and ___ on the mobilization of enegy stores
permissive; E and glucagon
bushings syndrome refers to
the collection of symptoms of abnormally high glucocortical levels
bushings disease refers to
the elevated cortisol due to excess ACTH due to pituitary tumor
what are 3 endogenous causes of bushings syndrome?
pituitary tumor, adrenal tumour, other
what is a exogenous cause of bushings syndrome?
taking medication with glucocorticoids, such as hydrocortisone
what is the most popular cause of bushings syndrome?
pituitary tumour (cushings disease
Addison’s syndrome refers to the collection of symptoms resulting from abnormally low ___ levels
low glucocorticoids
Addison’s disease can cause ___ of the hand
accentuate of normal pignetation
