questions

• what is turner's syndrome


  1 XO

  2 .gonards contain ovarian tissue but are rudimentary

  3 female phenotype

  no maturation at puberty
• characteristics of turner's syndrome

  broad chest ,poor breast development, short staure ,low hairline ,low set ears ,small fingernails.
• Klinefelter syndrome


  XXY

  testicular development but seminoferous tubules are abnormal

  no spermatogenesis
• Signs of Klinefelter Syndrome

  more breast tissuse ,small testes

  broader hips ,weaker bones ,less muscular small penis
• trisomy X super female

  xxx

  ovary abnormalities
• sign of trisomy x

  tall stature

  limited fertility

  learning disabilities

  small head

  ​
• true hermaphrodite

  has both ovarian tissue(with mature graffian follicles ) and testicular tissue(with distinct seminiferous tubules ) in a single individual

  commin karyotype xx
• causes of true hermaphrodite

  mutation of SRY gene

  two ova,fertilized by 2 sperm fuse to form tetragametic chimera ,if one male and female gamete fuse
• dorsal respiratory group location/site


  dorsal region of medulla, nucleus tractus solitarius
• role of DRG

  inspiration, inspiratory neurons ,set rythem of breathing
• mechanisms of DRG

  contains motor neurons which supply the diagram and neurons which input to VRG

  gradual inspiratory ramp signals
• what is DRG inhibited by

  pneumotaxic center
• ventral respiratory group location/site


  ventral region of medulla

  rostral nucleus retrofacialis , caudal nucleus retroambiguus and nucleus para-ambiguus
• role of ventral respiratory group

  involved in forced inspiration and expiration has inspiratory and expiratory neurons

  isn't active during quite breathing
• mechanism of ventral respiratory group

  contains motor neurons that supply the accessory inspiratory muscles

  contains motor neurons that inputs to expiratory muscles
• site of apneustic center

  cudal Pons
• role of apneustic center

  excitation of medullary inspiratory area

  believed to be involved in deep inspiration (apneusis)
• mechanism of apneustic center

  prolong inspiratory ramp ,sustained discharge of medullary respiratory neurons
• pneumotaxic center location

  rostral pons
• role of pneumotaxic center

  inhibits inspiration, hence facilitate expiration
• mechanism of pneumotaxic center

  switching off inspiratory ramp ,terminates inhalation
• what is responsible for the development of a male

  the sex determining region Y (SRY) gene
• what are the 3 cell types that the gonards are made of

  1. supporting cells ( sertoli cells & granulosa cells )

  2. stromal cells (leydig or theca cells )

  3. germ cells ( spermatogonia or oocytes )
• what two hormones are most important for the development of male gonards andinternal genitalia

  anti-Mullerian hormone and testosterone
• what hormone is responsible for male external genitalia

  dihydrotestosterone ( weaker androgen of testosterone )
• descibe how internal genitalia develops and the cells and hormones involved

  1. sertoli cells secret mullerian inhibiting hormone which causes the regression of the mullerian duct

  2. leydig cells produce testosterone which promotes the development of the wolffian duct

  3. because these cells are not present in females these hormones are not secreted so the mullerian duct is allowed to develop (becomes the oviduct )and due to the lack of testosterone the wolffian duct regresses
• what causes the brain to develop as a male


  the brain develops as a male in the presence of estrogen derived from neural aromatization of testosterone
• what causes the the brain to develop as a female

  the absence of estrogen ( no aromatization of testosterone)
• how are females protected against masculization of estrogen from fhe placenta of the mother

  alpha-feto protein (plasma glycoprotein ) binds to estrogen, acts as a carrier and prevents it from entering cells