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A&P 500 > Endocrinology > Flashcards

Endocrinology Flashcards

1
Q

Hormones

A

Mediator molecules that are released in one part of the body but that can regulate the activity of cells in other areas.

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2
Q

Functions of hormones

A
  1. Regulation
  2. Control growth and development
  3. Regulate operation of reproductive systems
  4. Help establish circadian rhythm
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3
Q

What do hormones regulate?

A

Chemical composition and volume of the internal environment.

Metabolism and energy balance

Contraction of smooth and cardiac muscle fibres

Glandular secretions

Some immune activity

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4
Q

Nervous vs. Endocrine: Mediator molecules

A

Nervous: neurotransmitters released locally in response to nerve impulse

Endocrime: hormones delivered to tissue throughout the body by blood

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5
Q

Nervous vs Endocrine: site of mediator action

A

Nervous: close to site of release; at synapse; binds to receptor in postsynaptic membrane

Endocrine: potentially far from site of release; binds to receptor in or on target cells

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6
Q

Nervous vs Endocrine: types of target cells

A

Nervous: Muscle cells, glands, neurons

Endocrine: cells throughout the body that affect metabolism, regulate growth and development, and influence reproduction

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7
Q

Nervous vs. Endocrine: time to onset of action

A

Nervous: usually within miliseconds

Endocrine: seconds to hours or days

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8
Q

Nervous vs. Endocrine: duration of action

A

Nervous: generally brief

Endocrine: generally longer (seconds to days)

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9
Q

Exocrine Glands

A

Epithelial cell(s) that secrete their products into ducts which carry them into body cavities, lumen, or outside of the body.

ex. sebaceous, mucous and digestive glands

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10
Q

Endocrine Glands:

A

Epithelial cell(s) that secrete hormones into the surrounding interstitial fluid.

The hormones diffuse into capillaries and are carried to the target cells.

ex. pituitary, thyroid, parathyroid, adrenal and pineal glands

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11
Q

Organs/tissue that secrete hormones but that aren’t exclusively endocrine

A 
Hypothalamus
Thymus
Pancreas
Ovaries/testes
Kidneys
Stomach
Liver
Small Intestine
Skin
Heart 
Adipose tissue
Placenta
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12
Q

How many receptors/target-cell?

A

2000-100000

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13
Q

Down regulation

A

When a substance (like a hormone) is present in excess, the number of receptors may decrease

  • some current receptors endocytosed and degraded
  • target cell now less sensitive to the substance

ex. insulin resistance

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14
Q

Up regulation

A

When the amount of a substance (like a hormone) is deficient, more receptors for that hormone are created, making the target tissue more sensitive.

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15
Q

Paracrine hormones

A

Act on neighbouring cells

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16
Q

Autocrine hormones

A

Act on the cell that secretes them

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17
Q

Two broad classes of hormones:

A

Lipid and water soluble

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18
Q

Three types of lipid soluble hormones

A
  1. Steroid hormones
    • derived from cholesterol (lipid + 4 carbon rings)
      - differ in attachment sites for chemical groups
      ex. testosterone and estrogen
  2. Thyroid hormones (T3, T4)
    - - made by attaching iodine to tyrosine
    - - made very lipid soluble by two benzene rings
  3. Nitric Oxide (NO)
    - - neurotransmitter and hormone (like NE and epinephrine)
    - - synthesis catalyzed by nitric oxide synthase
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19
Q

Transporter proteins (hormone)

A

For lipid soluble hormones that can’t circulate freely in blood plasma.

  1. make lipid soluble hormones temporarily water-soluble,
  2. retard passage of small hormones through kidney filters, slowing rate of hormone loss
  3. provide reserve of hormone, always present in bloodstream
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20
Q

Three types of water soluble hormones

A
  1. Amine hormones
    - modified decarboxylated amino acids
    - epinephrine, norepineprhine
  2. Peptide and protein hormones
    - amino acid polymers (peptide: 3-49; protein 50-200)
    - - oxytocin (peptide) insulin and HGH (proteins)
  3. Eicosanoid hormones
    - - derived from arachidonic acid
    - -important local hormones, but may circulate as well
    - - prostaglandins (PG) [cycloxygenase pathway]
    - - leukotrienes (LTs) [lipoxygenase pathway]
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21
Q

Permissive Effect

A

Hormone A arrives. Weak effect.
Hormone B arrives; doesn’t act directly on target, but strengthens effect of A.

ex. epinephrine breaking down triglycerides with the help of T3/T4

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22
Q

Synergystic Effect

A

Two hormones acting together have a greater or more more extensive effect than either alone. (FSH and estrogens –> oocyte development)

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23
Q

Antagonistic effect

A

Two hormones doing the opposite thing.

Insulin stimulates glycogenesis
Glucagon stimulates glycogenelysis

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24
Q

Activity of Lipid Soluble Hormones

A
  1. Free hormone diffuses through blood and interstitial fluid; diffuses though cell membrane into cytosol
  2. Binds to and activates receptor within nucleus or cytosol. Specific genes turned on or off
  3. DNA transcribed, new mRNA forms, and ribosomes synthesizes new protein (typically enzyme)
  4. Gene expression altered => new protein alter’s cell activity
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25
Q

Activity of Water Soluble Hormones

A
  1. Hormone [1st Messenger] binds to receptor on cell membrane.
  2. Receptor-hormone complex activates G protein
  3. G protein activates Adenylate Cyclase
  4. Adenylate Cyclase converts ATP –> cAMP [2nd Messenger]
  5. cAMP activates Protein Kinase
  6. Protein kinase phosphorylates cellular proteins, which activates some and inactivates others
  7. Phosphorylated proteins case reactions which cause physiological responses
  8. cAMP deactivated by phosphdiesterase
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26
Q

Why do hormones have such a large effect with such a low concentrations?

A

Water soluble can have a Cascade effect.

One hormone molecule can activate 100 G-proteins, each of which can activate 1000 cAMP, and each protein kinase can act upon 1000s of substrate molecules

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27
Q

Hormone secretion is regulated by:

A
  1. signals from the nervous system
  2. chemical changes in the blood
  3. other hormones
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28
Q

Negative feedback and hormones

A

Most common.

ex. low blood glucose –> glucagon –> increased blood glucose –> no more glucagon

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29
Q

Positive feedback and hormones

A

Less common

ex. childbirth –> oxytocin –> contractions –> oxytoxin –> contractions –> etc.

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30
Q

Adenylate Cyclase

A

Catalyzes conversion of ATP to c-AMP during action of water soluble hormones

Activated by G-protein

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31
Q

Protein kinase

A

Phophorylates proteins within cell, creating effect of water soluble hormones. Uses ATP.

Activated by c-AMP

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32
Q

What deactivates c-AMP?

A

Phosphodiesterase

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33
Q

Hypothalamus

A

Lies below thalamus; major link between nervous and endocrine systems

Secretes at least 9 hormones

Regulates virtually all aspects of grown, development, metabolism and homeostasis

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34
Q

Pituitary gland

A

AKA hypophysis

Lies in hypophyseal fossa of sella turcica of sphenoid bone

Secretes at least 7 hormones

Consists of anterior and posterior portions

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35
Q

Anterior Pituitary

A

Adenohypophysis

Accounts for 75% of the weight of the pituitary.
Composed of epithelial tissue (derived from roof of pharynx)

Consists of: pars distalis and pars tuberalis

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36
Q

Posterior Pituitary

A

Neurohypophysis

Composed of neural tissue. Extension of diencephalon

Doesn’t produce hormones; stores and releases oxytocin and ADH produced by hypothalamus

Consists of pars nervosa and infundibulum

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37
Q

Pars distalis

A

Largest portion of the anterior pituitary gland

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38
Q

Pars tuberalis

A

Part of anterior pituitary gland; forms sheath around infundibulum

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39
Q

Pars nervosa

A

Part of posterior pituitary gland

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40
Q

Infundibulum

A

Part of the posterior pituitary gland

Connects hypothalamus with posterior pituitary

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41
Q

Hypophyseal Portal System

A

How hypothalamic hormones reach the anterior pituitary gland

Internal carotid artery –> [branches into]

Superior hypophyseal artery (brings blood to hypothalamus) –> [at hypothalamus/infundibulum junction branch into]

Primary Plexus of Hypophyseal Portal System receive hormones from the Tuberal Region of the hypothalamus (dorsomedial, ventromedial and arcuate/tuberal nuclei)–> [drains into]

Hypophyseal portal veins (passes down outside of infundibulum) –> [splits again to form]

Secondary Plexus of Hypophyseal Portal System

Anterior Hypophyseal Veins –> general circulation

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42
Q

Neurosecretory Cells

A

Specialized cells above the optic chiasm that synthesize hypothalamic releasing and inhibiting hormones .

Store hormones in vesicles in axons; nerve impulses cause vesicles to exocytose, and hormones then diffuse into the primary plexus of the HPS.

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43
Q

5 Types of Anterior Pituitary Cell

A
  1. Somatotrophs
  2. Thyrotrophs
  3. Gonadotrophs
  4. Lactotrophs
  5. Corticotrophs
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44
Q

Somatotrophs

A

Anterior pituitary cells.

Stimulated by Growth Hormone Releasing Hormone (GHRH), aka somatocrinin

Inhibited by Growth Hormone Inibiting Hormone (GHIH), aka somatostatin.

Secrete hGH (aka somatropin), which act on liver cells to produce IGF

–> stimulation of body growth and metabolism regulation

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45
Q

Thyrotrophs

A

Anterior pituitary cells

Stimulated by Thyrotropin-releasing hormone (TRH).
[ May be inhibited by GHIH, depending on what page you’re reading]

Secrete thyroid stimulating hormone (TSH, AKA thyrotropin), which act on the thryoid to control thyroid secretions

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46
Q

Gonadotrophs

A

Anterior pituitary cells

Stimulated by Gonadotropin Releasing Hormone (GnRH)

Secrete FSH and LH, which act on gonads

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47
Q

Lactotrophs

A

Anterior pituitary cells

Stimulated by Prolactin Releasing Hormone (PRH)
Inhibited by Prolactin Inhibiting Hormone (PIH), which is dopamine

Acts on mammary glands to stimulate milk production

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48
Q

Corticotrophs

A

Anterior pituitary cells

Stimulated by corticotropin releasing hormone (CRH)
Melanocyte production inhibited by dopamine

Produce Adrenocorticotropic Hormone (ACTH), AKA corticotropin which act on the adrenal cortex to secrete glucocorticoids (like cortisol).
Also produce melanocyte-stimulating hormone

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49
Q

Human Growth Hormone

A

Released by anterior pituitary somatotrophs
AKA somatotropin
Released every few hours (especially during sleep)

Controlled by GHRH and GHIH

Regulated by blood glucose level

Most plentiful anterior pituitary hormone

Promotes synthesis of (or is transformed into?) IGF

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50
Q

Functions of IGFs

A

1a Increases cellular uptake of amino acids and accelerates protein synthesis –> growth
1b Decreases breakdown of proteins and use of amino acids for ATP production –> fast growth during development

  1. Enhances lipolysis
  2. Decreases glucose uptake to ensure availability for ATP production
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51
Q

Besides blood glucose level, what things stimulate hGH synthesis?

A

Decreased fatty acids and increased amino acids in blood
Deep sleep
Increased SNS

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52
Q

Thyroid Stimulating Hormone

A

Produced by thyrotrophs in anterior pituitary

Controlled by TRH. Negative feedback via circulating T3/T4 levels

Stimulates synthesis of T3 and T4

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53
Q

Follicle Stimulating Hormone

A

FSH

Produced by gonadatrophs in anterior pituitary
Targets gonads.

Stimulated by GnRH.

In women, stimulates development of secondary ovarian follicles and estrogen release.
In men, stimulates sperm production

Negative feedback via estrogen/testosterone levels

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54
Q

Luteinizing Hormone

A

LH

Produced by gonadotrophs in anterior pituitary

Stimulated by GnRH

In women triggers ovulation, formation of corpus luteum, and release of progesterone.
In men, stimulates testosterone secretion.

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55
Q

Prolactin

A

Produced by lactotrophs in anterior pituitary.

Initiates and maintains milk secretion.

Regulated by PRH and PIH (dopamine)

Synergistic (?) effort with estrogens, progesterone, glucocorticoids, hGH, thyroxine and insulin.

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56
Q

When not pregnant, what happens with prolactin each month?

A

Just before menstruation, PIH decreases, prolactin increases, and boobs get sore

57
Q

Adrenocorticotropic Hormone

A

ACTH

Released by corticotrophs in anterior pituitary.
Regulated by CRH

Acts on adrenal cortex to produce glucocorticoids like cortisol

58
Q

Melanocyte-stimulating Hormone

A

MSH

Released by corticotrophs in anterior pituitary
Regulated by CRH (stimulatory) and dopamine (inhibitory)

Increases skin pigmentation and may influence brain activity

59
Q

What nuclei in the hypothalamus supply the posterior pituitary?

A

Paraventricular (oxytocin)

Supraoptic (ADH)

60
Q

Hypothalamohyophyseal Tract

A

Axons from paraventricular and supraoptic nuclei, which extend to the blood capillaries in the posterior pituitary.

Paraventricular/supraorbital nuclei
Posterior pituitary
Capillary Plexus of Infundibular Process
Posterior hypophyseal vein

61
Q

Oxytocin

A

Produced by paraventricular nucleus

Enhances contraction of smooth muscle cells in wall of uterus and stimulates milk ejection from mammary glands

62
Q

Antidiuretic Hormone

A

ADH, or vasopressin

High osmotic pressure (decreased blood volume) stimulates osmoreceptors in hypothalamus. ADH secreted:

Works on:

  1. kidneys (increased water reabsorption, reduced urination)
  2. Sweat glands (decreases activity)
  3. Smooth muscles in walls of arterioles – constricts, increases BP

Low osmotic pressure (increased blood volume). ADH no longer secreted.

63
Q

Thyroid Gland

A

Inferior to larynx

Mostly made up of thyroid follicles

Only endocrine gland that stores its product in large quantities

64
Q

Thyroid follicles

A

Make up most of the thyroid gland
Microscopic spherical sacs surrounded by basement membrane

Wall composed of follicular cells, which are cuboidal or squamous when inactive, but cuboidal to columnar when under the influence of TSH

Produce thyroxine (T4) and triiodothyronine (T3)

65
Q

Parafollicular Cells

A

C Cells in thyroid gland. Lie between follicles

Produce calcitonin

66
Q

Calcitonin

A

Produced by parafollicular/C cells in thyroid
Decrease circulating calcium by increasing increasing osteoblast activity, inhibiting resorption by osteoclases, and accelerating Ca+ reuptake.

67
Q

Thyroid Hormone

A

Thyroxine/tetraiodothyronine (T4)
Triiodothyronine (T3)

Synthesized from iodine and tyrosine within thyroglobulin

Increase metabolism and protein synthesis

More T4 than T3 circulating, but T3 more potent.
(Most T4 converted to T3 inside cell)

68
Q

Formation of Thyroid Hormone

A
  1. Iodide trapping
  2. Thyroglobulin synthesis
  3. Oxidation of iodide
  4. Oxidation of tyrosine
  5. Coupling of T1 and T2
  6. Pinocytosis and digestion of colloid
69
Q

How does iodide enter follicular cell?
How does colloid re-enter follicular cell?
How does T3/T4 enter bloodstream?

A

Trapped and actively transported
Pinocytosis
Passive diffusion

70
Q

Thyroglobulin

A

Large glycoprotein synthesized by the rough ER in the follicular cells and modified by the Golgi bodies.

Contain tyrosine, which attach to iodine

71
Q

Colloid

A

Sticky material made when tyrosine on thyroglobulin is iodinated, forming T1 and/or T2

72
Q

Control of Thyroid Hormone secretion

A

Low levels of T3/T4, or low metabolic rate –>
Hypothalamus releases TRH, which enters hypophyseal portal vein –>
Thyrotrophs in anterior pituitary release TSH –>
TSH stimulates all aspects of follicular cell activity –>
T3 and T4 released, situation regulated.

73
Q

Functions of Thyroid Hormones

A
  1. Increase BMR
  2. Stimulates synthesis of Na/K pumps (Na-K ATPase)
  3. Stimulates protein synthesis and use of glucose and fatty acids for ATP production. Increases lipolysis and cholesterol excretion (decreases blood cholesterol)
  4. Enhances actions of catecholamines (epinephrine and NE) because they up-regulate beta receptors
  5. Accelerates body growth (with hGH and insulin)
74
Q

Calorigenic Effect

A

Increased ATP use –> increased heat

75
Q

Hyperthyroidism: symptoms

A

Increased heart rate, more forceful heartbeats, increased BP

76
Q

Miacalcin

A

Calcitonin extract derived from salmon that is 10x more potent than human calcitonin.
Rx for osteoporosis

77
Q

Parathyroid Glands

A

Posterior surface of lateral lobes of thyroid gland
Each side has an inferior and superior lobe

Contains chief (principal) cells, which produce PTH, and oxyphil cells (function unknown)

78
Q

Parathyroid Hormone

A

Increases circulating calcium (so opposes calcitonin)
Also major regulator of Mg+ and phosphate ions.

Increases number/activity of osteoclasts –> increase resorption
Also acts on kidneys (distal convoluted tubule)

79
Q

How does PTH act on kidneys?

A

Slows rate of Ca+ and Mg+ loss
Increases phosphate loss (more lost in urine than gained from bone so net phosphate loss)
Promotes formation of calcitrol

80
Q

Calcitrol

A

Active form of vitamin D
Synthesized in kidneys in response to PTH
Increases rate of Ca+, Mg+ and phosphate absorption from GI tract

81
Q

How are calcitonin and PTH regulated?

A

Blood calcium level, negative feedback.

Does NOT involve pituitary gland.

82
Q

Adrenal Glands

A

Paired glands, superior to each kidney.
Retroperitoneal space.

Two functional regions: cortex and medulla

83
Q

Adrenal Cortex

A

80-90% of the adrenal gland

Produces steroid hormones

84
Q

Adrenal Medulla

A

10-20% of the adrenal gland

Produces 3 catecholamine hormones (norepinephrine, epinephrine and dopamine)

85
Q

Three zones of the adrenal cortex

A
  1. zona glomerulosa
  2. zona fasciculata
  3. zona reticularis
86
Q

Zona glomerulosa

A

Outer zone of the adrenal cortex

Secrete mineralocorticoids.

87
Q

Mineralocorticoids

A

Secreted by the zona glomerulosa of the adrenal cortex.
Steroid hormones that affect salt and water balance

Major mineralcorticoid is aldesterone

88
Q

Renin-angiotensin-aldosterone (RAA) pathway

A

Dehydration, NA+ deficiency, hemorrhage (decreased blood volume)

  • -> decreased blood pressure
  • -> juxtaglomerula cells secrete renin
  • -> renin converts angitensinogen (produced by liver) into angiotensin 1
  • -> in capillaries, angiotensin converting enzyme (ACE) converts angiotensin 1 into angiotensin 2, which stimulates
  • -> adrenal cortex to secrete ALDOSTERONE, which
  • -> increases reabsorption of Na+ and H2O, and secretion of K+ and H+, which
  • -> increases blood volume and hence pressure
89
Q

Aldesterone

A

MIneralocorticoid secreted by zona glomerulosa of the adrenal cortex.

Stimulated by increased K+ levels and by angiotensin 2 (which is formed because of low blood pressure)

Acts on principle cells in DCT. Stimulates reabsorption of Na+ and water, and secretion of K+ and H+

90
Q

Zona fasciculata

A

Widest zone of the adrenal cortex. Middle layer; cells in long, straight columns
Secretes mainly glucocorticoids

91
Q

Glucocorticoids

A

Steroid hormones that act to regulate glucose metabolism. Secreted by zona fasciculata layer of the adrenal cortex.

Include cortisol (most abundant), corticosterone, and cortisone

Low circulating glucocorticoids/stress–> CRH release by hypothalamus –> ACTH release from anterior pituitary

92
Q

Effects of glucocorticoids

A
  1. Protein breakdown
  2. Glucose formation (gluconeogenesis)
  3. Lipolysis
  4. Resistance to stress
  5. Antiinflammatory effects (inhibit WBCs)
  6. Immune response depression
93
Q

Zona reticularis

A

Deepest layer of adrenal cortex.

Secrete small amounts of weak androgens. After menopause, only source of female estrogens

94
Q

Androgens

A

Steroid hormones that control development and maintenance of male sexual characteristics in vertebrate. In females affects libido and is converted to estrogen

Zona reticularis secretes dehydroepiandrosterone (DHEA)

95
Q

Adrenal Medulla

A

Inner part of the adrenal gland.
Modified ganglion of the ANS –> neural tissue without axons; clusters around blood vessels.

ANS sympathetic preganglionic fibres innervate chromaffin cells, which release epinephrine and norepinephrine.

96
Q

Epinephrine and Norephinephrine

A

Can act as either a neurotransmitter or hormone.

As hormones, released by adrenal medulla, intensify sympathetic responses in other parts of the body.

Stress/exercise –> hypothalamus –> sympathetic preganglion nerves –> chromaffin cells

97
Q

Effects of epinephrine and NE

A

–> increase rate and force of heart contraction, increase BP, increase blood flow to heart, liver, skeletal muscles and adipose tissue, dilate airways and increase circulating glucose and fatty acids

98
Q

Pancreatic Islets

A

Pancreas is both exocrine (acini) and endocrine islets (only 1% of the organ)

1-2 million/pancreas

99
Q

Types of pancreatic islet cells

A
  1. Alpha (A) 17% – glucagon
  2. Beta (B) 70%– insulin
  3. Delta (D) 7%– somatostatin
  4. F cells 6%– pancreatic polypeptide
100
Q

Glucagon

A

Released by alpha pancreatic islet cells in response to hypoglycemia and/or rise in blood amino acids

Increases blood glucose levels by acting on liver cells to promote glycogenolysis and gluconeogenesis

101
Q

Insulin

A

Released by the beta pancreatic islet cells in response to hyperglycemia.

Acts on various cells in the body to accelerated facilitated diffusion of glucose into cells, to speed the glycogenesis, and to increase uptake of amino acids into the cell to increase protein synthesis. Also speeds synthesis of fatty acids, and slows glycogenolysis and gluconeogenesis

Also suppresses glucogon secretion

102
Q

What other hormones/chemicals stimulate insulin secretion?

A

ACh (the NT released by the vagus nerve, which innervates the pancreatic islets)

hGH and ACTH (elevate blood glucose)

Arginine and Leucine (amino acids – present after eating protein)

Glucose-dependent insulinotropic peptide (GIP) - released by enteroendocrine cells in response to glucose

103
Q

Hormones released by the ovaries

A

Steroid hormones, including
2 estrogens *estradiol and estrone)
Progesterone
With FSH and LH–> menstrual regulation, preparation and maintenance of pregnancy, preparing mammary glands from lactation

Also produce Inhibin (inhibits secretion of FSH) and, during pregnancy, relaxin

104
Q

Hormones released by testes

A

Testosterone (regulates sperm production, stimulates development of secondary sexual characteristics)

Inhibin (inhibits FSH)

105
Q

Pineal Gland

A

Roof of third ventricle, between superior colliculi, covered by pia mater.

Consists of neuroglia and pinealocytes

Releases melatonin (amine hormone derived from seratonin)–> sleepiness

More released during darkness, and while asleep

106
Q

Pinealocytes

A

Secretory cells in pineal gland; secrete melatonin

107
Q

Thymus

A

Located between lungs, behind sternum, in mediastinum
Mostly immunological role

Produces:
Thymosin
Thymic Humoral Factor (THF)
Thymic Factor (TF)
Thymopoietin

All promote maturation of T cells

108
Q

Eicosanoids

A

Two main families: prostaglandins (PGs) and leukotrienes (LTs)

Every cells except RBCs

Synthesized from arachidonic acid (from membrane phospholipids)

Bind to membrane receptors and either inhibit or stimulated the synthesis of secondary messengers (like cAMP)

109
Q

Leukotrienes

A

LTs
Eicosanoid molecules

Stimulate chemotaxis of WBC and mediate inflammation

110
Q

Prostaglandins

A

PGs
Eicosanoid molecules

Alter smooth muscle contractions, glandular secretions, blood flow, reproductive processes, plate function, respiration, nerve impulse transmissions, lipid metabolism and immune response.

111
Q

Growth Factors

A

Mitogenic – stimulate cell division
Mostly autocrine or paracrine

6 important:
Epidermal GF (EGF)
Platelet derived GF (PDGF)
Fibroblast GF (FGF)
Nerve GF (NGF)
Tumor angiogenesis factors (TAF)
Transforming growth factors (TGFs)
112
Q

Epidermal growth factor

A

Produced in salivary glands

Stimulates proliferation of epithelial cells, fibroblasts, neurons and astrocytes.
Suppresses gastric juice secretion and some cancer cells

113
Q

Platelet derived growth factor

A

Produced in platelets

Stimulates proliferation of neuroglia, smooth muscle fibres and fibroblasts.

Maybe wound healing and atherosclerosis

114
Q

Fibroblast growth factor

A

Pituitary gland and brain

Proliferation of cells from mesoderm (fibroblasts, adrenocortical cells, smooth muscle fibres, chondrocytes, endothelial cells) and stimulates angiogenesis

115
Q

Nerve growth factor

A

Salivary glands and hippocampus

Growth of embryonic ganglia; neural hypertrophy and differentiation

116
Q

Tumor angiogenesis factors

A

Stimulates angiogenesis, organ regeneration and wound healing in normal and tumour cells

117
Q

Transforming growth factors

A

Alpha – like EGF

Beta – inhibits proliferation

118
Q

General Adaptation Syndrome

A

Stress response; the normal sequential homeostatic mechanisms which occur in response to stress

Controlled by hypothalamus
Three stages: 
1. Fight or flight
2. Resistance
3. Exhaustion
119
Q

Fight or flight

A

Nerve impulse from hypothalamus to sympathetic NS
–> adrenal medulla –> NE and epinephrine

Increased glucose and O2 to vital organs (brain, skeletal muscles, heart)

Decreased blood flow to kidneys –> RAA pathway –>increased BP

120
Q

Resistance Reaction

A

Hypothalamic releasing hormones. Longer than Fight or Flight.

CRH
GHRH
TRH

–> increased available glucose, decreased inflammation,

121
Q

Exhaustion

A

Loss of potassium, depletion of glucocorticoids, weakened organs.

Body cannot sustain resistance.

Prolonged exposure to high cortisol etc –> muscle wasting, immune suppression, ulceration of GI tract, failure of pancreatic beta cells (insulin)

122
Q

Pituitary Dwarfism

A

Hyposecretion of hGh during growth years

Organs fail to grow; childlike proportions

123
Q

Giantism

A

Hypersecretion of hGH during growth years.

Abnormal increase in length of long bones; normal proportions.

124
Q

Acromegaly

A

Hypersecretion of hGH during adulthood.

Epiphyseal plates already closed –> bones of hands, feet, cheeks, etc. thicken; eyelids, lips, tongue and nose enlarge, skin thickens.

125
Q

Diabetes insipidus

A

Defect in ADH receptor (nephrogenic) or inability of posterior pituitary to secrete ADH (neurogenic).

Excessive urination, dehydration.

126
Q

Congenital hypothyroidism

A

Present at birth. (cretinism) Hyposecretion of thyroid hormone

Severe mental retardation, stunted bone growth.
May present normally at birth because of presence of mother’s hormones

127
Q

Myxedema

A

Presentation of adult hypothyroidism

Women 5x men

Edema, bradycardia, low body temperature, cold sensitivity, dry hair and skin, muscular weakness, lethargy, weight gain. Reduced alertness

128
Q

Graves disease

A

Most common form of hyperthyroidism.
Autoimmune – antibodies mimic TSH
Women > men

Goiter, exopthalmos

129
Q

Goiter

A

Enlarged thyroid gland

130
Q

Hypoparathyroidism

A

Low levels of PTH –> low circulating Ca+ –> depolarizing neurons

–> twitches, spasms, tetany

131
Q

Hyperparathyroidism

A

Elevated PTH –> soft, brittle bones

Most often from tumour

132
Q

Cushing’s Syndrome

A

Hypersecretion of cortisol by adrenal cortex

Breakdown of muscle proteins and redistribution of body fat –> spindly arms and legs; moon face, buffalo hump, pendulous abdomen.

133
Q

Addison’s Disease

A

Hyposecretion of glucocorticoids and aldosterone

Autoimmune –> antibodies cause adrenal cortex destruction and/or block ACTH binding sites.

Asymptomatic until destruction severe (90%)
Mental lethargy, anorexia, nausea, vomiting, weight loss, hypoglycemia, muscular weakness. Bronzed skin.

134
Q

Pheochomocytomas

A

(Usually) benign tumuors of the chromaffin cells.
Hypersecretion of epinephrine, NE.

Tachycardia, high BP, elevated BMR

135
Q

Diabetes Mellitus

A

Inability to produce or use insulin

Polyuria, polydipsia, polyphagia

136
Q

Type 1 Diabetes

A

Pancreatic beta cells destroyed –> low insulin
Formally “insulin-dependent” or “juvenile”

Increased fatty acid breakdown –> buildup of ketone bodies –> decreased pH —> ketoacidosis

137
Q

Type 2 Diabetes

A

Formally “adult onset”. Mostly lifestyle related

Insulin supply adequate, but cells less sensitive to it due to down regulation of insulin receptors

138
Q

Hyperinsulinism

A

Most often from overmedication
–> hypoglycemia (too much uptake of glucose by body cells)

Anxiety, sweating, tremour, tachycardia, hunger, weakness.

A&P 500 (3 decks)

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