Development of body cavities

Question 1

what are the mesothelial lining of organs

Answer 1

pleura
pericardium
peritoneum

Question 2

what are the ectoderm 8

Answer 2

ecto SECENATE

Sense receptors in the epidermis

Epithelial lining of the mouth and rectum

Cornea and lens of eye

Epidermis of skin and its derivatives including sweat glands and hair follicles

Nervous system

Adrenal medula

Tooth enamel

Epithelium or Pineal and Pituritary glands

Question 3

what are the mesoderm 10

Answer 3

meso LENDCRAMMS

Lining of the body cavity

Excretory system

Notochord

Dermis of skin

Ciculatory and Lymphatic
system

Reproductive system except germ cells

Adrenal Cortex

Muscular system

Muscular layer of stomach, intestine etc

Skeletal system

Question 4

what are the endoderm 7

Answer 4

endo PEELLTT
Pancreas

Epitheal lining of digestive tract

Epitheal lining of respiratorry system

Liver

Lining of the urethra, urinary bladder and reproductive system

Thymus

Thyroid and Parathyroid glands

Question 5

what is found above the developing brain that will later go on to form the heart?

Answer 5

cardiogenic mesoderm

Question 6

from what does the anus form

Answer 6

the cloacal membrane

Question 7

from what does the mouth form

Answer 7

Oropharyngeal membrane

Question 8

what happens on day 21?

Answer 8

a. The trilaminar disc starts to become more specialised as the beginnings of the
nervous system begin to form.

Question 9

what happens on day 22?

Answer 9

The cardiogenic mesoderm develops in front of the oropharyngeal membrane and
will tucks underneath.

Question 10

what happens on day 26?

Answer 10

Ventral folding

tucking under these cavities bringing in the
walls of the yolk sac

such forms the foregut, midgut and hindgut

neural tissue in the cranial end becomes bigger to form the brain

Question 11

what is ventral folding

Answer 11

the tail ends start to fold inwards. This moves the developing heart underneath the developing membrane.

Question 12

what happens on day 28?

Answer 12

Umbilical cord forms. Gut and yolk sac only connected via umbilical cord, Umbilicus is only hiatus in anterior/ventral abdominal wall

Question 13

what is the Septum transversum

Answer 13

Precursor to the diaphragm which separates the thoracic and abdominal cavities.

Question 14

what are the Pericardioperitoneal canals

Answer 14

how the Pericardial and peritoneal cavities communicate

Question 15

why does the Pericardioperitoneal canals form

Answer 15

because the Septum transversum is incomplete dorsally.

Question 16

what are the lungs at 28 days

Answer 16

Lungs are an evagination of the ventral git wall cranial to septum transversum.

Question 17

Development of the lungs 5th week

Answer 17

Partitions grow medially from lateral body wall, pleuropericardial folds contain
phrenic nerves.

Question 18

Development of the lungs 6th week

Answer 18

Pleuropericardial folds continue to grow medially. Lungs expand laterally and

ventrally. Pleural cavities develop.
b. As pleuropericardial folds form coronally. Pleuroperitoneal folds form transversely,

Question 19

how is the diagraphragm formed?

Answer 19

Pleuroperitoneal folds form transversely

Question 20

which four embryonic structures fors the Definitive musculotendinous diaphragm derive from

Answer 20

a. Septum transversum
b. Pleuroperitoneal membranes
c. Dorsal mesentery of oesophagus
d. Mesoderm of body wall

Question 21

describe the Innervation of diaphragm

Answer 21

Initially septum transversum is at level of 3 rd , 4 th and 5 th cervical somites.

b. Migrating myoblasts bring nerve supply from C3, C4 and C5.
c. Definitive diaphragm descends into inferior thorax, cervical innervation maintained.

Question 22

what are the Developmental abnormalities of the diaphragm

Answer 22

The pericardioperitoneal canal sometimes fails to close which causes congenital
diaphragmatic hernia.
b. This causes lung compression and hypoplasia.
c. Causes eventration of the diaphragm.