Embryology - lung development diseases Flashcards
what are the 3 phases of antenatal human development
- how long dose these roughly last
pre-embryonic (0-3 weeks)
embryonic phase (4-8 weeks)
foetal phase (9-40 weeks)
what is the production of sperm
spermatogenesis
4 sperm are made per what
spermatogonium
what is the production of ovum called
oogenesis
what is made per oogonium
3 polar bodies and 1 ovum (viable for life)
what is the name of the diploid cell made by the sperm and ovum pro nucleus combining
Zygote
what happens in week 1 of fertilisation
a zygote is formed in the fallopian tube beside the ovary, as it moves along the fallopian tube and implants in the womb it forms a morula then blastocyst.
what is a morula
it is the first solid ball of cells formed after the single celled zygote
which parent is mitochondrial disease inherited from - why
the mother the mitochondrial DNA only comes form the ovum
what is a blastocyst
the next thing formed after a morula
what happens inside the blastocycst
a trophoblast is formed
a inner cell mass is formed
a blastocycst cavity is formed
what is the trophoblast
the other lining of cells made during the formation of a blastocycst
how dose the fertilised egg move through the fallopian tube
ciliate epithelium cells
what acute situation can occur because of abnormal ciliated epithelium
ECTOPIC PREGNANCY
what happens in week 2 of pregnancy
implantation in the endometrium
cells form bilaminar disc
placenta starts to form (last thing in the week)
in week 2 what dose trophoblast become
the CHIRON
what is the Chiron
a hand looking thing that implants in the endometrium
forms part of the placenta
secrets unman chorionic gonadotropin (HCG - pregnancy test)
what happens to the inner cell mass of the blastocyst in week 2
I flattens out and moves into the blastocyst cavity to make two cavities and the BILAMINAR DISC
what are the 2 layers of the bilaminar disc - position?
epiblast - closet to Chiron
hypoblast - below epiblast
what is the cavity above the epiblast called
Amniotic cavity
what is the cavity below the hypoblast called
the yolk sack
how does the embryo being to form
the layers and sacks being to fold inwards with the amniotic cavity being on the outside
what are the 3 main functions of the placenta
Foetal nutrition
transport of waste and gases
beginning of immunity
how do you distinguish between the two sides of the placenta
foetal = smooth surface, foetal blood vessels, umbilical cord
maternal = rough because of finger like processed
what are the 4 things that occur in week 3 of gestation
neurulation - neural tube formed
gastrulation - germ layers made
somite’s start to develop
early cardiovascular development
what happens at the stat of week 3
the primitive streak (spine like indent) is formed as epiblast cells fold in the centre and flood the lower space to make the ECTOderm (outside), MESOderm and ENDOderm (inside)
what is important about the formation of the ectoderm, mesoderm and endoderm (2)
the trilaminar disc is formed
cells have specialised
what is the notochord
what dose it do
a solid tube of cells that comes from the ectoderm down to between the mesoderm and endoderm
ENDUCES neural tube formation
what does the notochord become
the nucleus pulposus
the fluid within the annulus fibrosa that makes up the intravertebral disc
how dose the Neural tube form
cells induced in the ectoderm multiply on the midline - form the ectoderm plate that sinks down - forms neural tube between Ectoderm and Mesoderm
what happens as the neural tube thickens
it induces the thickening and splitting of the mesoderm
what 3 things form the the mesoderm - (inside to out)
paraxial mesoderm
intermediate plate mesoderm
lateral plate mesoderm
what does the lateral plate mesoderm split to form anterior first
it splits to form the somatic (anterior) and splenic (posterior) mesoderm’s
what forms between the two mesoderms derived from the lateral mesoderm
what does this become
the intraembryonic coelom
the peritoneum, pleura and body cavities
what happens in the embryonic period (4th-8th week)
folding into a tube
ORGANOGENESIS = development of organs
neural tube = fore, mid and hind brain
gut, hear and limb buds form
what happens as the embryo begin to fold (innermost first)
the endoderm folds in on the yolk sac to form the gut
the splachnic (visceral) and somatic (paritala) mesoderms fold around the front
the ectoderm folds around and encaplusulates the whole thing
what dose each paraxial mesoderm divide into
3 layers
dermatome, myotome, sclerotome
what does the dermatome form
dermis of skin
what does the myotome from
muscles
what does the sclerotome form
how can you tell
bones & vertebra
it is the most proximal ‘‘tome’’ to the neural tube
what dose the interior palte mesoderm form
urogenital system, kidneys and reproductive system
what dose the endoderm form
the gut and respiratory system
what is teratology
the study of when things go wrong during development
what is the leading cause of abnormal development
unknown aetiology (unknown cause)
what drug caused malformed limbs due to maternal use
thalidomide
what environmental factors effect development
6
drugs alcohol Tabaco infectious agents radiation genetic factors - maternal age
when is the highest risk of teratogenesis
why not earlier/ later?
3 - 8 weeks
earlier - more likely to die
later - ‘‘firm foundation’’ leads to less sensitivity to teratogenesis
what are the prenatal ways in which to diagnose malformations
blood
ultrasound - 12 weeks in
invasive - chronic villus sampling and amniocentesis
what is chronic villus sampling
when a tissue sample of the villi of the Chiron (finger like processes) is taken
what is amniocentesis
a sample taken with a hollow needle of the amniotic fluid
what are the postnatal ways in which to diagnose malformations
check for abnormalities in the
hip stability
fingers and toes
hearing
testes
when and where does development of the trachea and lungs begin
week 4
the ventral wall of the fore gut (early oesophagus)
what is the outgrowth from the foregut
the laryngotracheal groove
respiratory diverticulum
what dose the laryngotracheal grove then from
lung buds
what is a diverticulum
a tube leading from a cavity that has a dead end (blind tube)
what forms between the foregut and respiratory diverticulum
the oesophagotracheal septum
what happens when the oesophagotracheal septum is closed
the trachea and oesophogas are formed. with the trachea ventral and oesophagus dorsal
what is a fistula
when two tubes or organs connect to each other - that is abnormal or surgical
what is Atresia
a condition in which a orifice/ tube is abnormally closed/ missiong
what is a common fistula and Atresia in lung formation
Tracheoesophageal fistula (TOF) & Atresia
how does the plura form
how does it get into the fissions
the visceral pleura (splanchnic mesoderm) is alredy formed around the lung bud and as the lung buds grow and develops more lobes they punch into the visceral pleura around them
what are the 5 stages of lung buds
FOETAL embryonic pseudo glandular canalicular saccular
POSTNATAL
alveolar
when and what occurs during the embryonic stage of lung buds
the formation of the first lung buds
weeks 4- 7
when and what occurs during the pseudo glandular stage of lung buds
initial creation of conducting airways - no gas exchange elements
7-27 weeks
when and what occurs during the canalicular stage of lung buds
17-27 weeks
terminal bronchioles start to form respiratory bronchules - type 1/2 pneumocytes start to form
when and what occurs during the saccular stage of lung buds
27-40 weeks
formation of alveolar sacs which will further divide into alveoli
when and what occurs during the POSTNATAL stage of lung buds
32 weeks - 8 YEARS
formation of alveoli from terminal sacs
alveoli enlarge
95% of adul alveoli formed postnatally
what is sufricant a mixture of
phospholipids and proteins
Respiratory distress syndrome (RDS) effects how many neonates , how much of neonatal disease is RDS
effects 2% of neonates
makes up 30% of neonatal disease
what are the 4 surrounding embryonic components that make up the diaphragm
septum transversum
pleuroperitoneal membrane
dorsal mesentery of the oesophagus
muscular ingrowth from the lateral body walls
what dose the septum transversum form
form the central large tendon of the diaphragm (the bulk of the diaphragm)
what dose the pleuroperitoneal membrane form
the primitive diaphragm
what dose the dorsal mesentery of the oesophagus do
form the median portion and crura
what is the crura of the diaphragm
two tendinous like structures that bind to the vertebra below the diaphragm to be used as anchors
where does the septum transversum initially form
what happens, why is this important
opposite C3 - 5
it moves down during development into the diaphragm - BRINGS DOWN THE NERVES C3 - 5
what is the name of the nerve at C3 - 5
what dose it do
phrenic nerve
keeps the diaphragm alive
what 3 major defects lead to congenital abnormalities
the diaphragm doesn’t completely close
Herniation of abdominal contents into the chest
Pulmonary hypoplasia
what is a hernia
a bulge or protrusion of an organ through the structure or muscle that contains it
what is pulmonary hypoplasia
the incomplete development of the lungs = smaller or less alveoli
at what age can a premature baby survive - why?
late canalicular stage (22/23) weeks
there is the beginnings of airways that can partake in gas exchange - before then only conducting airways
what conditions occur during lung development in the conducting airways (4)
airway stenosis
airway malacia
pulmonary agenesis/hypoplasia
trachea-oesophageal fistula
what conditions occur during lung development in the respiratory airways (4)
bronchogenic cyst
lobar
emphysema
cystadenoma malformation
pulmonary sequestration
what is tracheo-bronchomalacia - symptoms (4)
barking seal like cough
recurrent croup - infection that leads to swelling in the trachea
stridor/wheeze
breathless on exertion
how is trachea-bronchomalacia - managed (4)
airway cleaning physiotherapy
antibiotics
avoid asthma treatment - bronchodilators
will resolve with time
what remodelling can occur due to pre-natal nicotine exposure
(4)
lung hypoplasia - incomplete development
reduced alveolarization
small airways - more likely to get obstructive syndromes (asthma…)
increased chance of infection
what antenatal features cause COPD
maternal malnutrition
foetal infection
prematurity
in utero nicotine exposure
how would a diaphragmatic hernia occur
pulmonary hypoplasia (bad lung development)
persistent pulmonary hypertension
what is disease associated with wet lung
transient tachypnea is due to the delayed absorption of foetal lung fluid
what is transient tachypnea associated with - what happens to new-borns with this
caesarean section
laboured and fast breathing but resolves within 24-72 hours
what disease is associated with surfactant deficiency
hyaline membrane disease (RDS)
what is another term for respiratory distress syndrome (RDS)
hyaline membrane disease
what is the treatment of RDS (3)
antenatal glucocorticoids
surfactant replacement
support
what is the outcome of hyaline membrane deficiency (RDS)
endogenous surfactant production kicks in by day 5
what is bronchopulmonary dysplasia
chronic neonatal lung disease
who is affected - what are the risk factors
premature babies are effected - due to the oxygen toxicity by being on mechanical infection
multifactorial
antenatal infection
genetic
oxygen toxicity
what is airway malacia
softening of the airway - leading to its collapse
what is pulmonary hypoplasia
congenital incomplete lung development
what is airway stenosis
congenital narrowing of the air way
what is a bronchogenic cysts
congenital defect when there is abnormal budding of the tracheal diverticulum
what is lobar emphysema
air enters the lung but cant escape - hyper inflation
what is cystadenoma malformation
congenital disorder - entire lobe of lung is replaced with a non working cystic piece of lung
what is pulmonary sequestration
congenital - lung tissue develop not attached to pulmonary arterial blood supply
what does HCG (human chorionic gonadotropin) do
helps maintain the endometrium
