The hypothalamus and pituitary gland work together to control other endocrine glands They are connected by the infundibulum Hypothalamus and Pituitary Gland Copyright 2014 John Wiley amp Sons Inc All rights reserved ID: 542304
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Slide1
Pituitary Gland & HypothalamusSlide2
The
hypothalamus
and pituitary gland work together to control other endocrine glands. They are connected by the infundibulum.
Hypothalamus and Pituitary Gland
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.Slide3Slide4
Master Gland
Controls growth & activity of the
Thyroid Gland, Adrenal Gland, Gonads, & Liver“Middleman” between the brain (CNS) and the peripheral endocrine organsPituitary hormones act on endocrine and non-endocrine
tissueLocated outside the blood-brain barrier
Pituitary GlandSlide5
Anterior lobe (adenohypophysis)
Comprises 75% of the weight of the pituitary glandSecretes 7 hormones.Posterior lobe (neurohypophysis) M
ade of neural tissue Releases two hormones/neuropeptides made by the
hypothalamus.Oxytocin
Vasopressin/ADH
Pituitary Gland
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.Slide6
Secretes
releasing
and inhibiting hormones that control the release of hormones by the pituitary gland. They reach the pituitary gland via the hypophyseal portal system.
HypothalamusSlide7
Hypophysiotropic Hormones
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.Slide8
Hypophyseal Portal System
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.Slide9
Human Growth
Hormone
- hGHThyroid-Stimulating Hormone - TSHFollicle-Stimulating
Hormone - FSH
Luteinizing Hormone - LH
Prolactin
- PRL
Adrenocorticotropic
Hormone
- ACTH
Melanocyte-Stimulating
Hormone
- MSH
Anterior Pituitary - Trophic
HormonesSlide10
a.k.a. Somatotropin
Most abundant AP hormone
Produced by somatotrophsAccount for majority of cells present in
AP1° - acts on liver (IGF)
GHRH stimulates; SST/GHIH inhibits
Human Growth Hormone (
hGH
/GH)Slide11Slide12
hGH Feedback Loops
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.Slide13
a.k.a. Thyrotopin
Produced by
thyrotrophs1°- acts on thyroid (T3/T4).
In mammals
thermogenesis
Stimulated by TRH
Thyroid-Stimulating Hormone (TSH)Slide14
a.k.a
Follitropin
Produced by gonadotrophsSpecifically, FSH-gonadotroph
1°- in men: promotes
spematogenesis; in women: follicular growth (estrogen/progesterone)
Stimulated by GnRH
Follicle-Stimulating Hormone (FSH)Slide15
a.k.a. Lutropin
Produced by
gonadotrophsSpecifically, LH-gonadotroph
1° -
in men: acts on testes (testosterone); in women: acts on ovaries (ovulation/CL)
Stimulated by GnRH
Luteinizing Hormone (LH)Slide16
Produced by
lactotrophs
A.k.a. mammotrophs
PRL increases during pregnancy and reaches maximal values at parturition
Milk production in post-partum
women
Stimulated by nursing infant
Prolactin (PRL)Slide17
a.k.a. Corticotropin
Produced by
corticotrophs1° action- stimulates steroid biosynthesis within the adrenal
cortex; cortisolStimulated by CRH
High cortisol =
Cushings
Disease
Low cortisol =
Addisons
Disease
Adrenocorticotropic
Hormone (ACTH)Slide18
a.k.a. Melanotropin
Produced by
corticotrophsDisperse melanin pigment in melanocytes in the skin
Not secreted in large
amounts by AP
Melanocyte-Stimulating Hormone (MSH)Slide19
Credit: Dr. Michael
Ormsbee
, Florida State UniversitySlide20
Negative feedback loops control the secretions of:
ThyrotrophsTSH
Gonadotrophs
LH, FSHC
orticotrophs
ACTH, MSH
Hypothalamus and
A.P.
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.Slide21
The
posterior pituitary gland
does not synthesize any hormones.It stores and releases from axon terminals two hormones: oxytocin (OT) anti-diuretic hormone (ADH
)/vasopressinAxons from the neurosecretory
cells form the hypothalamohypophyseal tract.
Posterior Pituitary
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.Slide22
Hypothalamus and Post. Pituitary
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.Slide23
Antidiuretic
hormone (ADH)/
vasopressinAmount secreted varies with blood osmotic pressure. Its function is to decrease urine output.Osmoreceptors
(neurons) in the hypothalamus monitor blood osmotic pressure. ↑ blood
volume causes ↓ ADH secretion ↓ blood volume causes
↑ ADH
secretion
Posterior
Pituitary - ADH
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.Slide24
ADH Feedback Loop
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.Slide25
The “cuddle” or “love” hormone
Active during parturition and post-partum
Stretching of cervix = ↑↑ oxytocin releaseResults in ↑ smooth muscle contractions of uterusAfter birth – responsible for milk let-down/ejection
Posterior Pituitary - Oxytocin
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.