Endocrine Glands
description
Transcript of Endocrine Glands
EndocrinologyEndocrinologyEndocrinologyEndocrinology
Salvador Dalí, 1952: Galatea of the spheres
Learning ObjectivesLearning ObjectivesLearning ObjectivesLearning Objectives
To understand what the reproductive To understand what the reproductive endocrine glands and hormones are.endocrine glands and hormones are.
To understand the characteristics To understand the characteristics and functions of these hormones.and functions of these hormones.
To understand how the To understand how the concentrations of these hormones in concentrations of these hormones in the blood are controlled.the blood are controlled.
• What is endocrinology?What is endocrinology?– Study of structure & function of endocrine Study of structure & function of endocrine
glands and the role of their secretions glands and the role of their secretions (hormones)(hormones)
• What is an endocrine gland?What is an endocrine gland?– Organs or groups of cells which produce Organs or groups of cells which produce
hormones and secrete them into the hormones and secrete them into the vasculaturevasculature
• What is a hormone?What is a hormone?– A chemical messenger which travels via the A chemical messenger which travels via the
circulation to reach target organs and circulation to reach target organs and subsequently elicit a specific effectsubsequently elicit a specific effect
Endocrinology ?Endocrinology ?Endocrinology ?Endocrinology ?
Present in Present in circulationcirculation in in lowlow amountsamounts
Inhibit or accelerate reactions in cellsInhibit or accelerate reactions in cells
Are not secreted at constant ratesAre not secreted at constant rates
Require a specific receptorRequire a specific receptor
Characteristics of Characteristics of hormones:hormones:
Characteristics of Characteristics of hormones:hormones:
Require a specific receptorRequire a specific receptor
Characteristics of Characteristics of hormones:hormones:
Characteristics of Characteristics of hormones:hormones:
Modes of TransmissionModes of TransmissionModes of TransmissionModes of Transmission
Endocrine:Endocrine: hormones transported by hormones transported by the blood to act on a distant organ. the blood to act on a distant organ. (classical definition)(classical definition)
Neuroendocrine:Neuroendocrine: hybrid; nerve hybrid; nerve secretes its chemical messenger, is secretes its chemical messenger, is taken into a capillary and carried to taken into a capillary and carried to many cells.many cells.
Modes of TransmissionModes of TransmissionModes of TransmissionModes of Transmission
Paracrine:Paracrine: hormones simply diffuse hormones simply diffuse directly to neighboring target cells, directly to neighboring target cells, by-passing the circulatory system.by-passing the circulatory system.
Autocrine:Autocrine: a given cell may respond to a given cell may respond to its own hormone secretion.its own hormone secretion.
Locations of Some Locations of Some Endocrine GlandsEndocrine GlandsLocations of Some Locations of Some Endocrine GlandsEndocrine Glands
Classes of Hormones: Classes of Hormones: ProteinsProteins
Classes of Hormones: Classes of Hormones: ProteinsProteins
Classes of Hormones: Classes of Hormones: SteroidsSteroids
Classes of Hormones: Classes of Hormones: SteroidsSteroids
Classes of Hormones: Classes of Hormones: ProstaglandinsProstaglandins
Classes of Hormones: Classes of Hormones: ProstaglandinsProstaglandins
Hypothalamus
Pituitary Gland
Reproductive HormonesReproductive HormonesReproductive HormonesReproductive HormonesHormoneHormone StructurStructur
e e OriginOrigin TargetTarget TargetTarget FunctionFunction
Gonadotropin Releasing Hormone (GnRH)
Decapeptide Hypothalamus Anterior PituitaryAnterior Pituitary
1. Stimulates the release of LH and FSH
Oxytocin
Octapeptide
Hypothalamus (Synthesized)
Posterior Pituitary
(Stored)
Smooth muscle of the epidydimal tail, vas deferens, and
ampulla
myometrium,
endometrium,
and mammary gland
1. Stimulates PGF2α synthesis
2. muscle contraction
Follicle Stimulating Hormone
(FSH)Glycoprotein Anterior Pituitary
testis
(sertoli cells)
ovaries
(granulosa cells)
1. Sertoli cell function
2. Spermatogenesis
1. Follicular development
2. Estradiol synthesis
Luteinizing Hormone
(LH)
Glycoprotein Anterior Pituitarytestis
(leydig cells)
ovaries
(thecal cells & luteal cells)
1. Stimulates testosterone
production
1. Stimulates ovulation
2. Induces formation of the
CL as well as
progesterone secretion
Reproductive HormonesReproductive HormonesReproductive HormonesReproductive HormonesHormoneHormone StructurStructur
e e OriginOrigin TargetTarget TargetTarget FunctionFunction
Prolactin Glycoprotein Anterior Pituitary Testis and Brain Mammary Gland
1. Stimulates milk production
2. Maternal behavior
1. Maternal behavior
Progesterone
(P4)Steroid
Corpus luteum and
Placenta* *(species specific)
-
Endometrium & myometrium,
hypothalamus, and mammary
gland
1. Maintenance of pregnancy
2. Inhibit GnRH release
3. Mammary growth and
secretion
Estradiol
(E2)Steroid
Sertoli cells
Granulosa Cells
Brain
Hypothalamus & pituitary, entire reproductive
tract, and brain
1. Regulate GnRH, LH & FSH
2. Increased secretory activity to enhance uterine motility
3. Sexual behavior (heat)
1. Sexual behavior
Testosterone
(T)Steroid
Leydig cells
Theca interna cells
Sertoli cells, accessory sex glands, brain, and skeletal
muscle
Granulosa cells, brain, and
skeletal muscle
1. Spermatogenesis
2. Promotes secretion of accessory glands
3. Secondary sex characteristics
1. Estradiol synthesis