Exam 2: Endocrinology Flashcards

1
Q

Identify three categories of hormones based on their chemical composition.

A
  1. Steroids
  2. proteins/glycoproteins/peptides
  3. Amines(derivatives of tyrosine)
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2
Q

Steroids- Chemical Composition

A

Cholesterol

fat soluble- need carrier to make water soluble

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3
Q

Proteins/glycoproteins/peptides- Chemical composition

A

Proteins: Amino acids-long

Glycoproteins: Protein and carbohydrate

Peptides: Amino acids- short

Water Soluble

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4
Q

Amines (tyrosine derivatives)- Chemical composition

A

Amino Acids

water soluble- adrenal

fat soluble- thyroid

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5
Q

Define Upregulation

A

an increase in the number of receptors on a target cell, which oftten occurs as a response to a prolonged decrease in the level of a hormone.

  • Increase the number of receptors
  • Decrease the level of hormone

Number of receptors on target cells may change

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6
Q

Define Downregulation

A

a decrease in the number of receptors on a target cell, in response to a prolonged increase in the level of a hormone.

  • decrease the number of receptors
  • increase the level of hormone

Number of receptors on target cells may change

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7
Q

Describe the mechanism of action of steroid hormones and thyroid hormones (tyrosine derivatives).

A
  • receptor within cytoplasma or nucleus
  • specific gene on DNA activated
  • message slightly amplified (multiple mRNA created)
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8
Q

Table 13.4: Sequence of Steroid Hormone Action

A
  1. Endocrine gland secretes steroid hormone.
  2. Blood carries hormone molecules throughout the body.
  3. Steroid hormone diffuses through target cell membrane and enters cytoplasm or nucleus.
  4. Hormone combines with a receptor molecule in the cytoplasm or nucleus.
  5. Steroid hormone-receptor complex binds to DNA and promotes transcription of messenger RNA.
  6. Messenger RNA enters the cytoplasm and directs protein synthesis.
  7. Newly synthesized proteins produce the steroid hormone’s specific effects.
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9
Q

Describe the mechanisms of action of proteins/glycoproteins/peptides and catecholamines from the adrenal medulla hormones (catecholamines are tyrosine derivatives).

A

“relay” race idea

  • receptor on cell membrane
    • water soluble goes through blood then stuck at cell membrane
  • binding of hormone (“first messenger”) activates adenylate cyclase
    • bind to surface receptor and don’t (never) enter cell
    • adenylate cyclase
      • G-protein- inactive until hormone shows up
  • “Second messenger” activated (often cAMP); also DAG, IP3, cGMP)
    • ATP to cAMP (activates proteins)- Don’t synthesize from scratch
  • Protein Kinases activated, metabolic processes altered
  • message is greatly amplified
    • 1 activates many
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10
Q

Table 13.5:Sequence of Actions of Nonsteroid Hormone Using Cyclic AMP

A
  1. Endocrine gland secretes nonsteroid hormone.
  2. bood carries hormone molecules throughout the body.
  3. Hormone combines with receptor site on membrane of its target cell, activating G protein.
  4. Adenylate cyclase molecules are activated in target cell’s membrane.
  5. Adenylate cylase converts ATP into cyclic AMP (cAMP)
  6. cAMP activates protein kinases
  7. Protein kinases activate protein substrates in the cell that change metabolic processes
  8. cellular changes produce the hormone’s effect
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11
Q

Describe how the hypothalamus, the nervous system, changes in the internal environment regulate the secretion of hormones by negative feedback. Be able to diagram these control mechanisms for specific hormones.

A

Diagram 13.8

Hypothalamic control via tropic hormones

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12
Q

Describe how the hypothalamus, the nervous system, changes in the internal environment regulate the secretion of hormones by negative feedback. Be able to diagram these control mechanisms for specific hormones.

A

Diagram 13.8

Direct stimulation of gland by nervous system

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13
Q

Describe how the hypothalamus, the nervous system, changes in the internal environment regulate the secretion of hormones by negative feedback. Be able to diagram these control mechanisms for specific hormones.

A

Diagram 13.8

Changes in composition of internal environment

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14
Q

Describe the anatomy of the pituitary gland.

A
  • anterior lobe (adenohypophysis)
    • made from gland tissue (epitheal tissue)
  • posterior lobe (neurohypophysis)
    • made from neural tissue- cannot produce its own hormones
  • Infundibulum
    • connects the hypothalamus to pituitary gland
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15
Q

Describe the function and regulation of the following hormones from the anterior pituitary gland: growth hormone, prolactin, thyroid-stimulating hormone, adrenocorticotropic hormone, follicle-stimulating hormone, luteinizing hormone. Regulation involves tropic hormones from the hypothalamus.

A

6 anterior pituitary gland hormones

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16
Q

Growth Hormone (GH)

(Somatotropin)

table 13.6

A

Function:

  • stimulates increase in size, number, and rate of division of body cells
  • promotes growth of long bones
  • enhances movement of amino acids through membranes
  • Protein synthesis

Regulation:

  • Secretion inhibited by somatostatin
  • stimulated by growth hormone- releasing hormone (GHRH) from the hypothalamus

Target Area:

  • body cells
17
Q

Prolactin (PRL or mammatropin)

table 13.6

A

Function:

  • Females: Sustains milk production after birth
  • amplifies ICSH in males

Regulation:

  • inhibitied by prolactic releasing-inhibiting hormone
  • stimulated by prolactin- relasing factor from the hypothalamus

Target area:

  • mammary glands
18
Q

Thyroid-stimulating hormone

(TSH or thyrotropin)

table 13.6

A

Function:

  • stimulates release of T3, T4
  • controls secretion of hormones from the thyroid gland

Regulation:

  • thyrotropin-releasing hormone (TRH) from the hypothalamus
    • TRH-> TSH=thyroid hormone-> hypothalamus

Target area:

  • thyroid gland
19
Q

Adrenocorticotropic Hormone

(ACTH or corticotropin)

table 13.6

A

Function:

  • controls release of COR (cortisol)
  • controls secretion of certain hormones from the adrenal cortex

Regulation:

  • corticotropin-releasing hormone (CRH) from the hypothalamus
    • CRH-> ACTH=cortisol -> hypothalamus

Target Area:

  • adrenal cortex
20
Q

Follicle-stimulating Hormone

(FSH, a gonadotropin)

table 13.6

A

Function:

  • promotes developmet of follicles and sperm
  • stimulates follicular cells to secrete estrogen

Regulation:

  • Gonadotropin-releasing hormone )GnRH) from the hypothalamus

Target area:

  • gonads
21
Q

Luteinizing Hormone

(LH, interstitail cell stimulating hormone or ICSH in males, a gonadotropin)

table 13.6

A

Function:

  • promotes secretion of male and female sex hormones
  • realeases egg cell in females

Regulation:

  • Gonadotropin-releasing hormone (GnRH) from the hypothalamus

Target area:

  • gonads
22
Q

Describe the function and regulation of the following hormones from the posterior pituitary gland: antidiuretic hormone, oxytocin.

A

2 hormones

23
Q

Antidiuretic Hormone

(ADH or vasopressin)

table 13.6

A

Function:

  • descreases water loss; may raise blood pressure

Regulation:

  • hypothalamus in response to changes in body fluid concentration and blood volume

Target Area:

  • Kidney tubules
24
Q

Oxytocin

table 13.6

A

Function:

  • Stimulates uterine contractions
  • stimulates milk let-down

Regulation:

  • hypothalamus in response to stretching uterine and vaginal walls and stimulation of breasts

Target area:

  • uterus
  • breast