the pituitary hormones
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The Pituitary Hormones. Chapter 13. (c) 2003 Brooks/Cole - Thomson Learning. Hypothalamic-Pituitary Systems. The pituitary is controlled largely by the hypothalamus : interaction of the nervous and endocrine system. Three separate glands Anterior lobe: endocrine, 6 hormones - PowerPoint PPT PresentationTRANSCRIPT
The Pituitary Hormones
Chapter 13
Slide 2(c) 2003 Brooks/Cole - Thomson Learning
Fig 13-1b, pg 410
Hypothalamus
Pituitary stalk
Posterior lobe
Intermediate lobe
Pituitary gland
Anteriorlobe
Optic chiasm
Hypothalamic-Pituitary Systems
The pituitary is controlled largely by the hypothalamus: interaction of the nervous and endocrine system.
Three separate glands
Anterior lobe: endocrine, 6 hormones
Intermediate : minor, 1
Posterior : neuroendocrine, 2
Slide 3(c) 2003 Brooks/Cole - Thomson Learning
Fig 13-3, pg 412
To venous circulation
Arterial blood supply
Posterior pituitary
Supraopticnucleus
Paraventricularnucleus
Hypothalamus
Posterior pituitary contains the axons from the neurons that have their cell bodies in the hypothalamus.
Slide 4(c) 2003 Brooks/Cole - Thomson Learning
Fig 13-4, pg 413
Cell bodies of neurons that produce releasing/inhibiting hormones Hypothalamus
Primary capillaries in median eminence
Arterial flow
Releasinghormones
Anteriorpituitaryhormone
LongPortalveins
ANTERIORPITUITARY
Secretory cells that produce anterior pituitary hormones
Anterior pituitary hormonesVenous outflow
Gonadotropic Thyroid-Proactin hormones stimulating ACTH Growth (FSH and LH) hormone hormone
Hypothalamus releases hormones at median eminence and those hormones are carried to anterior via portal vein.
Slide 5
Oxytocin and ADH are synthesized in soma in hypothalamus and released from nerve terminals in post. Pituitary.
Various inputs influence supraoptic and paraventricular neurons to control secretion.
Arterial inflow
Venous outflow
Supraoptic nucleus
Paraventricular nucleus
Cell bodies of neurons that produce posterior pituitary hormones
Posterior pituitary
capillaries
Slide 6
Hypothalamic releasing hormones travel to ant. pit. and control secretion from cells there.
One hypothalamic hormone may control more than one ant. pit. hormone (stim. or inhibit).
Slide 7
Posterior Pituitary Hormones
Effect: water retention by kidneys
Stimulator: 1) an increase in osmolality in blood and ECF 2) a large decrease in blood volume
Antidiuretic hormone (ADH)
Slide 8
Suckling and other stimuli trigger oxytocin release to transfer milk from alveoli to ducts.
Posterior Pituitary Hormones
Slide 9
Anterior Pituitary Hormones
Somatotropes (50%) = GH
corticotropes (20%) = ACTH
thyrotropes (5%) = TSH
Gonadotropes (5%) = LH and FSH
Lactotropes (variable) = Prolactin
Slide 10
LH and FSH (the gonadotropins) :promote production of sperm, egg, and sex steroids.
Prolactin Stimulation of alveolar cells to make milk.Release is controlled by PRF and PIH (DA)
ACTH is controlled by CRH;
Promotion of the synthesis and secretion of cortisol from adrenal cortex
Anterior Pituitary Hormones
Slide 11
(c) 2003 Brooks/Cole - Thomson Learning
Fig 13-5, pg 418
Sleep
6 AMMidnight6 PMNoon
Time of day
Plasma GHconcentration(relative units)
GH is released in pulses, with a major peak during deep sleep before REM.
Growth Hormone
Slide 12
(c) 2003 Brooks/Cole - Thomson LearningFig 13-6, pg 419
Somatomedins
Liver
Growth hormone
Somatotrophs ofAnterior pituitary
Somatostatin(-)
GHRH (+)
Portalvein
Hypothalamus
Sleep centerIn the brain
Chemicalstimuli
Stress centersIn the brain
GHRH and somatostatin in hypothalamus; final pathway for controlling GH
Growth Hormone
StimulatorDeep sleep, low blood glucose stimulationStress
physical traumainfectionpsychological stress
Amino acid (especially, arginine)
InhibitorREM sleepHigh blood glucose stimulation
Slide 13
GH effects: tissue growth (including bone growth)
Anabolic hormone
Growth Hormone
Insulin-like GH effects: liver and muscle protein synthesis;
anti-insulin: inhibits glucose uptake
Slide 14
(c) 2003 Brooks/Cole - Thomson Learning
Fig 13-7a, pg 420
GROWTH HOMONE
MUSCLE LIVER ADIPOSE
Insulin-likeeffects of GH
Anti-insulineffects of GH
Amino aciduptake
Proteinsynthesis
Glucoseuptake
Lipolysis
Decreased adiposity
RNAsynthesis
Glucoenogenesis
Somatomedinproduction
Proteinsynthesis
Glucoseuptake
Increasedmuscle mass
Growth Hormone
Slide 15Fig 13-7b, pg 420
SOMATOMEDINS
CHONDROCYTES OF BONE MANY ORGANS AND TISSUES
Increased lineargrowth
Increased tissue growthIncreased organ size
Collagen synthesis
Protein synthesis
Cell proliferation
Protein synthesis
RNA synthesis
DNA synthesis
Cell size and number
IGF-IIIGF-I
IGF-I stimulates bone growth by stimulating chondrocytes, which make cartilage.
Growth Hormone
Slide 16
SOMATOMEDINS
CHONDROCYTES OF BONE MANY ORGANS AND TISSUES
Increased lineargrowth
Increased tissue growthIncreased organ size
Collagen synthesis
Protein synthesis
Cell proliferation
Protein synthesis
RNA synthesis
DNA synthesis
Cell size and number
IGF-IIIGF-I
IGF-II stimulates tissue growth and repair by stimulating RNA and protein synthesis.
Growth Hormone
Slide 17
Deficiency
Childhood deficiency results in dwarfismAdulthood: not evident symptom
Growth Hormone
Slide 18
Overproduction
Gigantism is childhood GH excess; acromegaly from adulthood GH excess.
Growth Hormone
Slide 19
TSH: stimulates thyroid cell growth and secretion of thyroid hormone
Thyroid-Stimulating Hormone
Slide 20(c) 2003 Brooks/Cole - Thomson Learning
Fig 13-10, pg 422
Larynx
Thyroid gland
Thyroid isthmus
Trachea
The thyroid gland has two large lobes below the larynx, rich blood supply, and large growth capacity
Weight: 10-20 g
Thyroid-Stimulating Hormone
Slide 21
Thyroid-Stimulating Hormone
The thyroid gland consists of cells that are arranged in follicles. In a healthy adult, there are 3 million follicles.
Slide 22
Each thyroid follicle is filled with colloid and major component of colloid is thyroglobulin.
Thyroid-Stimulating Hormone
Slide 23(c) 2003 Brooks/Cole - Thomson Learning
Fig 13-13, pg 424
Tyrosine
Monoiodotyrosine (MIT) Diiodotyrosine (DIT)
T4 (thyroxine)
T3
Thyroxine (T4) and
triiodothyronine (T3) are its main
products; MIT and DIT are minor.
Slide 24
(c) 2003 Brooks/Cole - Thomson LearningFig 13-14, pg 425
Thyroglobulinsynthesis
Basal surface
Amino acids
Thyrogloblulin
Apical surfaceThyroglob-ulin, the T4
and T3
precursor, is a glyco-protein secreted into the colloid. Interstitial fluid
Slide 25
(c) 2003 Brooks/Cole - Thomson Learning
Fig 13-14, pg 425
Iodinetrap
Coupling
Iodination
Iodideoxidation
Thyrogloblulin
Thyroglobulin tyrosine is iodinated to MIT/DIT and coupled to make bound T3 and T4.
Interstitial fluid
Slide 26
(c) 2003 Brooks/Cole - Thomson Learning Fig 13-14, pg 425
Plasma
T3 T4
Deiodeinase
Phagolysosome
Lysosome
Pinocytosis
Follicle cells endocytose some colloid, fuses it with lysosomes, and releases T3 and T4.
Slide 27(c) 2003 Brooks/Cole - Thomson Learning
Metabolismof
carbohydrates,proteins, and fats
Biologicaleffects
Heatproduction
T3 and T4
Thyroidgland
TSH
I-
Anteriorpituitary
TRH
Hypothalamus
Otherbraincenters
Temperature-regulatoryCenters (hypothalamus)
Environmentalinfluences
Hypothalamic-pituitary-thyroid axis
Low temperature hypothalamus TRH
pituitary TSH
thyroid T4/T3
body.
Slide 28
Iodide deficiency low T4/T3
low feedback inhibition high TSH goiter.
Slide 29
T3 is more potent than T4, and
target cells convert T4 to T3.
Slide 30
Thyroid hormones
•Stimulate calorigenesis
•Increase circulatory sensitivity to sympathetic nervous system.
•Increase oxygenation of blood
•Increase
glucose uptake, glycogen formation, lipolysis,
biphasic protein synthesis
Effects of thyroid hormone
Slide 31
Thyroid hormones
• Promote bone growth
• Promote development of nervous system
1. Neural branching
2. Myelinization of nerve
Effects of thyroid hormone
Slide 32
Excess secretion; Hyperthyroidism
Symptom
high metabolism,
High heart rate;
weight loss;
heat intolerance.
Slide 33
Excess secretion; Hyperthyroidism
Slide 34
Excess secretion; Hyperthyroidism
Slide 35
Slide 36
Slide 37
Hypothyroidism
Deficiency of thyroid hormone
Slide 38
Slide 39