L01 - The HPG Axis

Beschreibung

RED Mindmap am L01 - The HPG Axis, erstellt von chris.brees am 22/01/2014.
chris.brees
Mindmap von chris.brees, aktualisiert more than 1 year ago
chris.brees
Erstellt von chris.brees vor fast 11 Jahre
22
0

Zusammenfassung der Ressource

L01 - The HPG Axis
  1. Hypothalamus
    1. Found at the base of the brain, between the midbrain and forebrain
      1. Collection of brain nuclei/centres
        1. Controls endocrine function via pituitary gland
          1. Gonadotrophin releasing hormone (GnRH)
            1. Short-life peptide
              1. Pulsatile GnRH secretion at puberty triggers gonad activation
                1. Continuous secretion leads to down regulation of GnRH receptors on gonadotroph cells
                  1. Causes lack of LH/FSH release
                  2. Can block GnRH effects using antagonist or agonist (due to resulting downregulation of receptors)
                  3. Pituitary Gland
                    1. Pea-sized gland at the base of the brain
                      1. Hormone secretion regulated by thalamus and by feedback loops from circulating hormones
                        1. Anterior pituitary hormones in reproduction
                          1. Gonadotrophins
                            1. FSH
                              1. Secreted by gonadotroph cells (ant. pit.)
                                1. Acts on sertoli (testes) and granulosa (ovary) cells
                                  1. Has an alpha chain, a beta chain and two carbohydrate chains
                                    1. Receptor LHCGR
                                    2. LH
                                      1. Secreted by gonadotroph cells (ant. pit.)
                                        1. Acts on leydig, theca and granulosa cells
                                          1. Has an alpha chain, a beta chain and a carbohydrate chain
                                            1. Receptor LHCGR
                                            2. hCG
                                              1. Human corionic gonadotrophin
                                                1. Secreted by trophoblast cells
                                                  1. Acts of luteal cells in the corpus luteum
                                                    1. Has an alpha chain, a beta chain and two carbohydrate chains
                                                      1. FSHR
                                                    2. Bind to cell surface receptors and signal via G-proteins
                                                    3. Proteins and Peptides
                                                      1. ACTH - corticotrophs
                                                        1. GH - somatotrophs
                                                          1. Prolactin - lactotrophs
                                                        2. Communication
                                                          1. Direct - neural to post. pit.
                                                            1. Indirect - vascular to ant. pit.
                                                              1. GnRh produces in parvocellular neurons and travels to ant.pit. in portal blood
                                                                1. Stimulates FSH and LH production
                                                              2. Hypophyseal portal system
                                                            2. Gonads
                                                              1. Different for males and females
                                                                1. Sex steroids and regulatory factors produced
                                                                  1. Sex steroids
                                                                    1. Progestagens
                                                                      1. Pregnancy
                                                                        1. Progesterone
                                                                          1. 17alpha-OHP
                                                                            1. 20alpha-OHP
                                                                              1. Functions
                                                                                1. Preparation of the uterus
                                                                                  1. Maintenance of the uterus during pregnancy
                                                                                    1. Growth of mammary glands
                                                                                      1. Suppression of lactation
                                                                                        1. Catabolic effects
                                                                                          1. Regulation of gonadotrophins
                                                                                          2. Receptors
                                                                                            1. PR-A
                                                                                              1. PR-B
                                                                                            2. All derived from cholesterol
                                                                                              1. Androgens
                                                                                                1. Male
                                                                                                  1. DHT
                                                                                                    1. Testosterone
                                                                                                      1. Androstenedione
                                                                                                        1. DHEA
                                                                                                          1. Functions
                                                                                                            1. Development and maintenance of the male reproductive system
                                                                                                              1. Secondary sexual characteristics
                                                                                                                1. Sexual function
                                                                                                                  1. Support spermatogenesis
                                                                                                                    1. Regulation of gonadotrophins
                                                                                                                    2. Receptors
                                                                                                                      1. AR - polymorphic with differing sensitivites to androgens
                                                                                                                    3. Oestrogens
                                                                                                                      1. Female
                                                                                                                        1. Oestradiol 17beta
                                                                                                                          1. Puberty to menopause
                                                                                                                          2. Oestriol
                                                                                                                            1. Pregnancy
                                                                                                                            2. Oestrone
                                                                                                                              1. Post-menopause
                                                                                                                              2. Functions
                                                                                                                                1. Secondary sexual characteristics
                                                                                                                                  1. Stimulate growth and activity of mammary glands
                                                                                                                                    1. Stimulation proliferation of endometrium for progesterone action
                                                                                                                                      1. Regulate gonadotrophins
                                                                                                                                      2. Receptors
                                                                                                                                        1. ERalpha
                                                                                                                                          1. ERbeta
                                                                                                                                        2. Lipid soluble, act via steroid response elements (SREs)
                                                                                                                                          1. Bound to carrier proteins
                                                                                                                                            1. Albumin
                                                                                                                                              1. Sex hormone binding globulin (SHBG)
                                                                                                                                                1. Androgen binding protein (ABP)
                                                                                                                                                2. Steroid action
                                                                                                                                                  1. Potency
                                                                                                                                                    1. Depends on affinity of steroid to receptor
                                                                                                                                                      1. Varies within each class
                                                                                                                                                        1. Cross-occupancy
                                                                                                                                                          1. Some bind receptors from other classes
                                                                                                                                                            1. Side-effects result
                                                                                                                                                            2. Some bind but don't activate
                                                                                                                                                              1. Antagonists
                                                                                                                                                          2. Regulation
                                                                                                                                                            1. Alter amount of steroid produced
                                                                                                                                                              1. Regulated by and regulate gonadotrophins of ant. pit.
                                                                                                                                                                1. Feedback loops
                                                                                                                                                              2. Alter amount or structure of receptor
                                                                                                                                                                1. Important in reproduction - gives better picture than hormone levels
                                                                                                                                                        2. Negative feedback in males, complicated feedback in females
                                                                                                                                                      2. Clinical aspects
                                                                                                                                                        1. Fertility
                                                                                                                                                          1. For females, endocrine problems are a common cause of infertility
                                                                                                                                                          2. Central Hypogonadism
                                                                                                                                                            1. Hypothalamus/pituitary problem
                                                                                                                                                              1. Low FSH/LH
                                                                                                                                                              2. Primary Hypogonadism
                                                                                                                                                                1. Ovary/testes problem
                                                                                                                                                                  1. Lack of feedback
                                                                                                                                                                    1. High FSH/LH
                                                                                                                                                                    2. Prolactin
                                                                                                                                                                      1. Inhibits HPG axis when in high doses
                                                                                                                                                                        1. Levels increase in pregnancy and breast feeding
                                                                                                                                                                          1. Inhibits gonadal activity through central suppression of GnRH
                                                                                                                                                                            1. Induces lactational amenorrhea
                                                                                                                                                                            2. The Menstrual Cycle
                                                                                                                                                                              1. Cyclic gametogenesis, once per month
                                                                                                                                                                                1. Hormonal changes cause folliculogenesis and endometrium changes
                                                                                                                                                                                  1. Three phases
                                                                                                                                                                                    1. Follicular/proliferative
                                                                                                                                                                                      1. Ovulation
                                                                                                                                                                                        1. Luteal/secretory
                                                                                                                                                                                        2. Duration
                                                                                                                                                                                          1. 26-32 days
                                                                                                                                                                                            1. Follicular phase varies
                                                                                                                                                                                            2. Luteal phase
                                                                                                                                                                                              1. 14 days
                                                                                                                                                                                              2. Fertile period
                                                                                                                                                                                                1. Oocyte - 24 hours
                                                                                                                                                                                                  1. Sperm - 5 days
                                                                                                                                                                                                    1. Oligomenorrhea
                                                                                                                                                                                                      1. <9 cycles in last 12 months
                                                                                                                                                                                                      2. Amenorrhea
                                                                                                                                                                                                        1. No bleed in 6 months
                                                                                                                                                                                                          1. Primary - since birth
                                                                                                                                                                                                            1. Secondary - ceased
                                                                                                                                                                                                        2. Menopause
                                                                                                                                                                                                          1. Females - finite number of oocytes
                                                                                                                                                                                                            1. Ovulation ceases around 50
                                                                                                                                                                                                              1. Lack of progesterone/oestrogen production by ovary
                                                                                                                                                                                                            2. Removal of -ve feedback leads to high FSH/LH levels
                                                                                                                                                                                                              1. Higher FSH closer to menopause
                                                                                                                                                                                                            3. Test for ovulation on day 21
                                                                                                                                                                                                            4. Treatments/uses
                                                                                                                                                                                                              1. Hormonal contraception
                                                                                                                                                                                                                1. Synthetic progestagens and oestrogens
                                                                                                                                                                                                                  1. Suppress ovulation
                                                                                                                                                                                                                    1. Thickens cervical mucous
                                                                                                                                                                                                                      1. Thins endometrium
                                                                                                                                                                                                                    2. Fertility treatment
                                                                                                                                                                                                                      1. IVF/ICSI
                                                                                                                                                                                                                        1. Down-regulate HPG axis with GnRH agonist/antagonist, stimulate with FSH, induce oocyte maturation with hCG
                                                                                                                                                                                                                        2. Prostate cancer treatment
                                                                                                                                                                                                                          1. GnRH agonists suppress T cell production
                                                                                                                                                                                                                      Zusammenfassung anzeigen Zusammenfassung ausblenden

                                                                                                                                                                                                                      ähnlicher Inhalt

                                                                                                                                                                                                                      HyunA - Red lyrics Quiz
                                                                                                                                                                                                                      Eunha Seo
                                                                                                                                                                                                                      Specimen tubes
                                                                                                                                                                                                                      Pip Fraggle
                                                                                                                                                                                                                      Wilson Avenue Red's Tool Brands
                                                                                                                                                                                                                      rmayich
                                                                                                                                                                                                                      Tests
                                                                                                                                                                                                                      Pip Fraggle
                                                                                                                                                                                                                      Gold BD Hemogard Closure or Red-Gray/Tiger Speckled topped tube
                                                                                                                                                                                                                      Pip Fraggle
                                                                                                                                                                                                                      Intro To Haematology & Normal Red Cells
                                                                                                                                                                                                                      Matthew Coulson
                                                                                                                                                                                                                      Fichas memoristicas
                                                                                                                                                                                                                      Adriana Amarillas
                                                                                                                                                                                                                      Red's (Wilson ave ) Logo's
                                                                                                                                                                                                                      rmayich
                                                                                                                                                                                                                      Red, Plastic, Glass Tubes
                                                                                                                                                                                                                      Pip Fraggle
                                                                                                                                                                                                                      Enter text here
                                                                                                                                                                                                                      Jesus Castellanos
                                                                                                                                                                                                                      FICHAS MEMORÍSTICAS
                                                                                                                                                                                                                      paula barron