The Endocrine Syste, Flashcards

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1
Q

Glands

A

organs of the endocrine system that secrete hormones

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2
Q

Hormones

A

signaling molecules that are secreted directly into the bloodstream to travel to target tissue

they bind to receptors and induce a change in gene expression or cellular function

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3
Q

Hormones can be classified into the following:

A

Peptides

Steroids

Amino Acid Derivatives

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4
Q

Peptide hormones

A

made up of amino acids and can be small to large

derived from larger precursor polypeptide cleaved during posttranslational modification; small units go to golgi apparatus for modifications to activate hormone and released by exocytosis

rapid but short lived effects as they act through transient second messenger system meaning easier to turn on and off

water soluble and do not require carriers, travel through blood stream

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5
Q

Because peptide hormones are ____, they cannot pass through the plasma membrane and must bind to _____

A

charged

extracellular receptor

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6
Q

First messenger

A

ie. peptide hormones

bind to receptor and trigger transmission of second signal/second messenger

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7
Q

Signaling Cascade

A

connection between hormone and the effect caused by the secon messengers

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8
Q

Amplification

A

one hormone may bind to multiple receptors before degradation

each receptor will activate multiple enzymes and trigger production of large quantities of second messengers

each step increases intensity of signal

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9
Q

Common Secondary Messnegers

A

cyclic adenosine monophosphate (cAMP)

inositol triphosphate (IP3)

Calcium

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10
Q

G Protein Coupled Receptor

A

1) Peptide hormone binds and triggers receptor to EITHER ACTIVATE OR INHIBIT adenylate cyclase
2) this raises or lowers levels of cAMP
3) cAMP binds to protein kinase A and phosphorylates transcription factors such as cAMP and then exert hormones true effect

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11
Q

Steroid Hormones

A

derived from cholesterol and produced in gonads/adrenal cortex

non polar molecules that easily cross the cell membrane

slower but longer lived than peptide hormones as they alter mRNA and protein present by affecting DNA

non water soluble and carried by protein

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12
Q

Receptors of steroid hormones are usually _____ or ______.

The hormone-receptor complex undergoes ______ which can the bind directly to ______ resulting in increased or decreased _________

A

intracellular (cytosol) or intranuclear (nucleus)

conformational change

DNA

transcription of genes

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13
Q

Dimerization

A

pairing of two receptor-hormone complezes

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14
Q

Steroid Carrying Proteins

A

specific and cary only one specific hormone

non specific

Note, homrones are inactive while in carrier protein

LEVELS OF CARRIER PROTEIN CAN IMPACT LEVELS OF ACTIVE HORMONE (more carrier protein, less hormone as it is bound to protei)

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15
Q

Amino Acid Derivative Hormones

A

less common than peptide and steroid hormones

derived from one or two amino acids with a few modifications

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16
Q

Catecholamines

A

epinephrine and norepinephrine

bind to g protein couple receptors while thyroid hormones bind intracellularly

17
Q

Direct Hormones

A

secreted and act directly on a target tissue

ie insulin causing increased uptake of glucose by msucles

18
Q

Tropic Hormones

A

require and intermediary to act , stimulate preoduction of another hormone to induce an action

ie: originate from the brain or anterior pityitary gland

19
Q

Endocrine Glands

A
Hypothalamus
Pituitary
Thyroid
Parathryoid 
Adrenal
Pancreas
Gonads
Pineal
20
Q

Kidney, gastroinsstial glands, heart and thymus secret hormones but are not endocrine organs because…

A

hormone production is not main function

21
Q

Hypothalamus

A

bridge between nercous and endocrine systems

regulates pituitary gland hrough tropic hormones

Location: forebrain between thalamus and pituitary

release of hormones is regulated by negative feedback where hormone produced inhibits homrones earlier in pathway

22
Q

Suprachiasmatic Nucleus

A

receives light input from retinae to control sleep wake cycle

23
Q

Hypothalamus and Anterior Pituitary

A

hypothalmus secretes into HYPOPHYSEAL PORTAL SYSTEM and bind to receptors in anterior pituitary to stimulate release of hormones

24
Q

Hypophyseal Portal System

A

blood vessel system connecting hypothalamus and anterior pituitary

hence hormones secreted by the hypothalamus cannot be in appreciable concentrations in systemic circulation

25
Q

Hypophysis

A

alternative term for pituitary

26
Q

Hypothalamus Tropic Hormones Affectiong Anterior Pituitary Hormones

A

GnRH -> LH and FSH
GHRH -> GH
TRH -> TSH
CRF -> ACTH

27
Q

Exception in Hypothalamus and Pituitary Relation

A

Prolactin-inhibiting factor (dopamine) decreases prolactin secretion!

28
Q

Three Organ Systems Axes

A

Hypothalamic-Pituitary-Adrenal (HPA)

Hypothalamic-Pituitary-Ovarian (HPO)

etc

29
Q

Hypothalamus and Posterior Pituitary

A

axons of hypothalamus to pituitary

  • Oxytocin Released: stimulates contractions during labor and milk
  • ADH/Vasppressin: increases reabsorption of water in collecting ducts of kidney s
30
Q

ADH is released from ______ and secreted in response to _____ or _______. It ______ the duct towards water and results in ______ of water leading to ____ blood pressure and volume.

A

posterior pituitary

increased plasma osmalarity

increased concentration of solutes within the blood

increases permeability

retention of

increase

31
Q

Anterior pituitary secretes ____ tropic hormones and ____ direct hormones.

A

4

3

32
Q

Tropic Hormones

A

cause he release of another hormone at the organ level

ex: GnRH stimulates release of FSH and LH from the anterior pituitary

33
Q

Direct Hormones

A

Prolactin stimulates milk production

Endorphins decrease perception of pain

Growth Hormone promotoes growth of bone and muscle and is energetically expensive by preventing glucose uptake and stimulate the breakdown of fatty acids by some tissues so gucose is available for muscle and bone

34
Q

Prolactin _____ from the release of dopamine from the hypothalamus

A

decreases

35
Q

Gigantism vs Dwarfism

A

excess growth hormone vs less growth hormone in childhood

36
Q

Acromegaly

A

GH impacts the smaller bones such as those in hands and feet

37
Q

Posterior Pituitary contains ______ in the hypothalamus. ITs two hormones are _______. THey are produced in _____ and stored in _____

A

nerve terminals of neurons with cell bodies in hypothalamus

ADH and Oxytocin

hypothalamus

posterior pituitary