Timeline Mammary gland

-



1 timeline

1.1 before birth
1.2 growth
1.3 pregnancy
1.4 postmenopausal





timeline
before birth

mammary gland development characterized unique process epithelium invades stroma. development of mammary gland occurs after birth. during puberty, tubule formation coupled branching morphogenesis establishes basic arboreal network of ducts emanating nipple.


developmentally, mammary gland epithelium produced , maintained rare epithelial cells, dubbed mammary progenitors thought derived tissue-resident stem cells.


embryonic mammary gland development can divided series of specific stages. initially, formation of milk lines run between fore , hind limbs bilaterally on each side of midline occurs around embryonic day 10.5 (e10.5). second stage occurs @ e11.5 when placode formation begins along mammary milk line. give rise nipple. lastly, third stage occurs @ e12.5 , involves invagination of cells within placode mesenchyme, leading mammary anlage (biology).


the primitive (stem) cells detected in embryo , numbers increase steadily during development


growth

postnatally, mammary ducts elongate mammary fat pad. then, starting around 4 weeks of age, mammary ductal growth increases ducts invading towards lymph node. terminal end buds, highly proliferative structures found @ tips of invading ducts, expand , increase during stage. developmental period characterized emergence of terminal end buds , lasts until age of 7–8 weeks.


by pubertal stage, mammary ducts have invaded end of mammary fat pad. @ point, terminal end buds become less proliferative , decrease in size. side branches form primary ducts , begin fill mammary fat pad. ductal development decreases arrival of sexual maturity , undergoes estrous cycles (proestrus, estrus, metestrus, , diestrus). result of estrous cycling, mammary gland undergoes dynamic changes cells proliferate , regress in ordered fashion.


pregnancy

during pregnancy, ductal systems undergo rapid proliferation , form alveolar structures within branches used milk production. after delivery, lactation occurs within mammary gland; lactation involves secretion of milk luminal cells in alveoli. contraction of myoepithelial cells surrounding alveoli cause milk ejected through ducts , nipple nursing infant. upon weaning of infant, lactation stops , mammary gland turns in on itself, process called involution. process involves controlled collapse of mammary epithelial cells cells begin apoptosis in controlled manner, reverting mammary gland pubertal state.


postmenopausal

during postmenopause, due lower levels of estrogen, , due lower levels of gh , igf-1, decrease age, mammary gland tissue atrophies , mammary glands become smaller.








Comments

Post a Comment

Popular posts from this blog

Prosodic bootstrapping Bootstrapping (linguistics)

-
1 prosodic bootstrapping 1.1 prosodic cues syntactic structure 1.2 prosodic cues clauses , phrases 1.3 criticism prosodic bootstrapping even before infants can comprehend word meaning, prosodic details assist them in discovering syntactic boundaries. prosodic bootstrapping or phonological bootstrapping investigates how prosodic information — includes stress, rhythm, intonation, pitch, pausing, dialectal features — can assist child in discovering grammatical structure of language or acquiring. in general, prosody introduces features reflect either attributes of speaker or of utterance type. speaker attributes include emotional state, presence of irony or sarcasm. utterance-level attributes used mark questions, statements, , commands, , can used mark contrast. prosodic features associated speaker: emotional state, irony, sarcasm prosodic features associate utterance type: question, statement, command, contrast similarly, in sign language, prosody includes facial expression, mouthing, , r...
Read more

Principal leitmotifs Music of The Lord of the Rings film series

-
1 principal leitmotifs 1.1 first appearance in fellowship of ring 1.2 first appearance in 2 towers 1.3 first appearance in return of king 1.4 reprised themes hobbit 1.5 themes of hobbit principal leitmotifs howard shore s composition not carry motifs on either other scores of career or passages of existing film or stage music, exception of 1 intentional nod richard wagner on end-credits of third film. shore wrote long series of interrelated leitmotifs used, developed, combined or fragmented throughout 3 scores. motifs attached places, cultures, characters, objects , occurrences. while stage , film composers deviated meaning of themes , used them romantically (i.e. suggestion of mood) shore refrains using technique. several pieces feature intriguing thematic choices choosing history of 1 ring theme passage of argonath or ringwraith theme orc armies in prologue (and again azog in hobbit) neither outright romantic in application , can explained. history of ring being main theme o...
Read more

List of masters Devon and Somerset Staghounds

-
1 list of masters 1.1 north devon staghounds 1.2 chichester s hounds 1.3 devon , somerset staghounds list of masters hugh pollard , master in 1598. (sir hugh ii pollard of king s nympton, father of sir lewis pollard, 1st baronet (c. 1578–c.  1645)) edward ii dyke (d. 1746), portrait circa 1741 attributed thomas hudson (1701–1779), national trust, collection of dunster castle edward dyke (d. 1746), of pixton, in somerset, (eldest brother of thomas dyke (d. 1745) of tetton , of john dyke (d. 1732) of holnicote, in somerset), warden , lesee of royal forest of exmoor , master of staghounds, office held warder. married margaret trevelyan, daughter of sir john trevelyan, 2nd baronet (1670–1755), of nettlecombe in somerset, , widow of alexander luttrell (1705–1737) of dunster castle. edward inherited holnicote , estates in bampton brother john dyke (d. 1732), died without progeny. died without progeny , bequeathed pixton , holnicote niece elizabeth dyke (d. 1753), whom appointed sole executo...
Read more