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Anatomy (Pharm 110) > 9.3 Endocrine > Flashcards

9.3 Endocrine Flashcards

1
Q

describe the thyroid gland

A
  • largest endocrine gland-> lateral lobes conencted via isthmus
  • FOllicle cells produce the glycoprotein thyroglobulin

- colloid (thyroglobulin and isodine) fills the lumen of the follicles

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2
Q

what are the effects of thyroid hormone

A

* major emtabolic hormone

  • -TH is concerned with:
    • glycose oxidation
    • increasing metabolic rate
    • heat production
  • -TH plays a role in:
    • maintaining blood rpessue
    • regulating tissue growth
    • developing skeletal and nervous sytems
    • maturation and reprofuctive capabilities
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3
Q

What are the exceptions of the areas that are not affected by the thyroid gland

A

* will have an exam question

USTAT

uterus, spleen, testis, adult brain (role in neural development in younger kids), thyroid gland (doesnt target itself)

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4
Q

What are the 2 types of thyroid hormones

A

T4 - Thyroxine; two tyrosine molecules plus 4 iodine

T3 - Triiodothyronine; two tyrosines with 3 iodine

Synthesis

  1. Thyroglobulin (constains 134 tyrosine) is synthesized and discharged into the lumen, only hanful actually used
  2. I- taken into cell actively, oxidized to I2 and released into lumen
  3. thyroid perioxidase attached iodine to tyrosine, forming T1 (MIT) and T2 (DIT)
  4. thyroid peroxidase links togther to form T3 and T4
  5. Endocytosis of T3 and T4 are cleaves in lysoomes and diffuse into blodo stream
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5
Q

describe the transport and regulation of TH

which is mroe active

A

T4 and T3 bind to thyroxine binding globulins (TBGs or thyroxine binding protein, TBP) produced by liver

  • both bind to target receptors but T3 is 5-10x more active
  • peripheral tissues (target tiss) convert T4 -> T3 via deiodinase
  • mechanisms of activity are simialr to sterioids
  • hypothalamic thyroprotin-releasing hormone (TRH) can overcome the negative feedback
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6
Q

Describe Hypothyroidism

A
  • symptoms include: low metabolic rate, lethargy, mental slugishmess
  • Low T4 and possible T3 leads to higher THS (unless pituitaru problem)
  • lack of I2 can lead to enlarges thyorid (goiter)

*tries to make more TH increases colloid space -> causes thyorid gland to grwo really big

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7
Q

what is cretinism

A

form of hypothyroidism found in infants

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8
Q

what is graves disease

A
  • autoimmune disease that most commonly afects the thyorid, causes it to grow twice its size or more (goiter)
  • symptoms include increased heartbeat, muscle weakness, dsiturbed sleep and iritability
  • it can also affect the eyes, causing bulging (exophthalamos)
  • abnormal antibodies that mimic TSH and continuously stimulate TH release (act and bind to thyroid gland)
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9
Q

what is calcitonin

A
  • peptide hormone rpduced by parafollicular, or C-cells
  • lowers blood Ca2+ in children and targets skeleton
  • > inhibits osteoclast activity and release of Ca2+
  • Stimulates Ca2+ incorporation into bone matrix
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10
Q

describe the parathyroid glands

A
  • tiny glands embedded in the posterior aspect of the thyroid
  • cells are arranged in cords containing oxyphyl and chief cells
  • chief (principal) cells secrete parathyorid hormone (PTH) whihc reg Ca2+ balance in blood
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11
Q

what are the effects of parathyroid hormone

A
  • stimulates osteoclasts
  • Enhances the reabsorption of Ca2+ and the secretion of phosphate by the Kidneys
  • promotes Vitmain D activation to calcitriol whihc increases Ca2+ abs of the intestine

*Cising Ca2+ in blood inhibits PTH release

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12
Q
A
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13
Q

describe the adrenal galnds

A

contains

adrenal medualla: neural tissue that acts as part of the sympathetic nervous system (SNS)

Adrenal cortex: releases steroid hormones called corticosteroids (>24)

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14
Q

what are the layers of the adrenal cortex and the corticosteroids produced at each layer

A

Zona glomerulosa - mineralocorticoids (mostly aldosterone)

Zona fasciculata - glucocorticoids (mostly cortisol)

Zona reticularis - gonadocorticoids (mostly androgens)

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15
Q

all steroids are derived from

A

cholesterol

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16
Q

estrogen synthesis, which form is most potent

A

E2 i the most potent

E1 (estrone) can make E2 (estradiol) or E3 (Estriol)

E2 can also be used yo make E3

17
Q

describe mineral corticoids

A
  • produced in Zona glomerulosa of adrenal cortex
  • regualte electrolytes in extracellular fluids

Aldosterone most important mineralocorticoid

  • > Maintains Na+ by reducing excretion of Na+ from the body
  • > Stimulates reabsorption of Na+ by the kidneys
18
Q

what stimulates teh secretion of aldosterone

A

􏰃 Rising blood levels of K+
􏰃 Low blood Na+
􏰃 Decreasing blood volume or pressure

19
Q

what methods regulate aldosterone

A
  1. Renin-angiotensin mechanism
    • angiostensin II stimulates aldosterone release
  2. Inc plasma K+ (Na+), directly influences the zona glomerulosa cells
  3. ACTH causes small increases of aldosterone during stress
  4. Atrial natriuretic peptide (ANP) inhibits activity of zona glomerulosa
    • only inhibitory one
20
Q

What do glucocorticoids do

A

aka cortisol

  • ex include: cortisol (hydrocortisone), cortisone and corticosterone
  • help to resist stress by: keeping blood sugar rel constant & maintaining blood volume and preventing water shift into tissue
    provokes: glyconeogensis (glucose formation) and rises in blood glucose, fatty acids and amino acids
21
Q

what happens if these is an excess in the levels of glucocorticoids

A
  • Depress cartilage and bone formation
  • Inhibits inflammation and the immune system
  • Promote changes in cardiovascular, neural, and GI function
22
Q

what are Gonadocorticoids

A

sex hormones

  • most are androgens (male sex hormones), most ipmortant is testosterone
  • contrubute to: onsert of puberty, secondary sex characteristics and sex drive in females (produced in adrenal cortex)
  • can be converted into estrogens after menopause
23
Q

what does the adrenal medulla secrete

A

*more interior part

  • Chromaffin cells secrete catecholamines (epinephrine and norepinephrine)
  • Increases blood glucose levels during short term stress
  • Epinephrine
    • potent stimulator of the heart
      • bronchiole dilation
      • increases blood flow to skeletal muscle, brain and heart
  • Norepinephrine
    • peripheral vasoconstriction and blood pressure
24
Q

how does the adrenal gland respond to stress (short term)

A

adrenal medualla secretes epinpehirne and norep

inc HR, inc BP, liver conversts glycogen to glucose to release in blood

dilation of bionchioles

changes in blood flow patters to dec digestive system actiivty and reduce urine output

inc metabolic rate

25
Q

how does the adrenal galnd respond to stress (long term)

A
  • hypothalamus released CRH -> anterior pit, ant pit releases ACTH
  • targets adrenal cortex to release mineralcorticoids and glucocorticoids
  • Mineralcorticoids
    • retention of sodium and water by kidneys
    • inc blood volume and blood pressure
  • Glucocorticoids
    • proteins and fats converted to glucose or broken down for energy
    • inc blood glucose
    • suppression of immune system
26
Q

what is glucagon

A

A 29-amino-acid hormone that is a potent hyperglycemic agent

  • secreted by alpha cells of the pancreas
27
Q

What is insulin

A
  • 51 amino acid protein with two amino acid chains linked by disulfide bonds
  • released by beta cells
  • enhances tranposrt of glucose into cells
  • counters metabolic activity that would enhance blood glucose levels

*goes to lvier, inc glycolysis, glycogenesis and lipogenesis to descrease plasma glucose

28
Q

how are bloog glucose levels regulated

A
  • Too high
    • pancrease releases insulin
    • stimulates glucose uptake by cells and glycogen formation by liver
  • Too low
    • pancrease releases glucagon that stim glycogen breakdown in the liver
29
Q

type 1 vs type 2 diabetes

A
  • Type 1
    • typically early onset
    • autoimmune disorder that rends to run in families resulting in beta cell death
    • needs insulin injections
  • Type 2
    • Usually adult onset and tends to occur in obese sedentary people
    • cells do not respond to insulin
    • usually deit and exercise are important for control
30
Q

what is diabetes mellitus?

what are the long term effects

A
  • type 1
  • inability to control blood glucose

long term effects: blindness, loss of limbs, nerve deterioration, kidney and cardiovascular disease

31
Q

what are the 3 cardinal signs of diabetes Mellitus

A

􏰃 Polyuria - huge urine output
􏰃 Polydipsia - excessive thirst
􏰃 Polyphagia - excessive hunger and food consumption

32
Q

describe the gonads in females

A
  • paired ovaries in the abdominopelvic cavity produce estrogen and progesterone
  • responsible for
  • > maturation of reproductive organs
  • > appearance of secondary sexual characteristics
  • > breast development and cyclic changes in uterine mucosa
33
Q

describe the gonads in males

A
  • testes are located in the extra abdominal sax (scrotum)
  • > produce testosterone

Testosterone

  • > initiates maturation of male reproductive organs
  • > causes appearance of secondary sexual characteristics and sex drive
  • > is necessary for sperm production
  • > maintains sex organs in their functional state
34
Q

location of pineal gland and whats it involed in

A

Small gland hanging from the roof of the third ventricle of the brain that secretes melatonin

  • Melatonin is involved with day/night cycles, show rhythmic variations (body temperature, sleep, appetite)

*helps the SCN sense the length of the night

35
Q

what is the SCN? where is it?

A

Endogenous circadian peacemaker is the Suprachiasmatic nucleus (SCN)

  • located in the anterior ventral hypothalamus

*Internal clocks allow us to anticipate and synchronize brain and body functions so they occur at appropriate and optimal times

36
Q

what is the thymus

A

Lobulated gland located deep to the sternum

  • Hormonal products are thymopoietins and thymosins
  • Essential for the development and education of T lymphocytes (T cells) of the immune system thymus
37
Q

what hormone does adipose tissue secrete

A
  • leptin
    • peptide hormone
    • secretion of leptin is proportional to fat stores; increased by nutrient uptake
    • acts on brain to suppress appetite and increase energy expenditure
  • Resistin & adiponectin
    • peptide hormones
    • unknown trigger
    • acts on fat, muscle, liver
      • resistin antagonized insulins action
      • adiponectin enhances insluins action
38
Q
A

Anatomy (Pharm 110) (41 decks)

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