What are endocrine systems for?

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What are endocrine systems for?

• Endocrine Functions
• Maintain Internal Homeostasis
• Support Cell Growth
• Coordinate Development
• Coordinate Reproduction
• Facilitate Responses to External Stimuli

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What are feedback systems?
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How dynamic are these systems?
Hormone, receptor, transducer effector levels
vary with time. Some change over short terms,
others over long terms. Levels also vary with
developmental stage, gender, health status.
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How dynamic are these systems?
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How dynamic are these systems?
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How dynamic are these systems?
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Outline of Male Reproduction
1. Adult anatomy 2. Embryogenesis 3. Sex
determination 4. Hormonal controls 5.
Puberty 6. Testicular anatomy 7. Meiosis
8. Spermatogenesis 9. Contraception 10.
Aging
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Adult Male Anatomy
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Male Embryogenesis
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Male Germ Cell Migration
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Male Germ Cell Migration
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Sex Determination Genetic
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Sex Determination Genetic
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Sex Determination Gonadal
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Sex Determination Gonadal
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Sex DeterminationInternal Reproductive Tract
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Sex DeterminationExternal Reproductive Tract
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Pituitary- Hypothalamic Associations
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How are the gonads controlled? LH
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How are the gonads controlled? FSH
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Inhibin
Female
Males lack inhibin A. Inhibin B is inversely
correlated with FSH spermatogenesis in normal
adults.
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Steroid Synthesis
arbl.cvmbs.colostate.edu/hbooks/pathphys/endocrine
/basics/steroidogenesis.gif
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Maturation Hormonal
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Maturation Hormonal
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Leydig Cell Populations
Lejeune, H, R Habert, JM Saez, Origin,
proliferation and differentiation of Leydig
cells, J Mol Endocrinol 201-25, 1998.
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Maturation Tanner Stages
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Maturation Tanner Stages
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Testosterone in saliva in children serum SHBG
in adolescents adults. The pubertal decrease
in SHBG is less pronounced in women.
www.biomedcentral.com/content/figures/1471-2431-2-
5-3-l.jpg
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Testicular Anatomy
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Testicular Anatomy
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Meiosis Males Females
Male
Female
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Spermatogenesis
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Sperm Maturation
Spermatozoa reach final shape in the testis, but
they gain functional maturity while passing
through the epididymus female reproductive
tract activation of full motility,
capacitation, in the vagina cervix final
fertilizing ability after the acrosome reaction,
usually near the egg.
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Fertilization
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Male Contraception
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Male Serum Hormone Age Profiles
Male Aging Reproductive Senescence
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The ratio T/SHBG is the FAI, a Measure of free T.
Adrenal androgens like DHEAS also decline with
age.
www.dpcweb.com/documents/newsviews/spring_02/the_
aging_male.html
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Low Fertility in Gainj vs Other Groups
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How is prolactin controlled?
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FSH in Gainj Men
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LH in Gainj Men
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Many Gainj Men are Infertile
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Support from NSF, Umass/Boston, Sandia National
Labs, Hybritech, Quidel, Monoclonal Antibodies
Inc.
(in the lab at UMB)
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Male Hormone Levels with Age
www.dpcweb.com/documents/newsviews/spring_02/the_
aging_male.html