Exam 4

Question 1

Each pharyngeal arch consists of what?

Answer 1

Core of mesenchyme

Question 2

Mesenchyme is covered externally by what?

Answer 2

ectoderm (grooves or clefts)

Question 3

Mesenchyme is lined internally by what?

Answer 3

Endoderm

Question 4

Derivatives of the 1st pharyngeal arch muscle & nerve

Answer 4

Muscles of mastication
CN V (trigeminal)

Question 5

Derivatives of the 2nd pharyngeal arch muscle & nerve

Answer 5

Stapedius, stylohyoid, posterior belly of digastric, facial expression muscles
CN VII (facial)

Question 6

Derivatives of the 3rd pharyngeal arch muscle & nerve

Answer 6

Sylopharyngeus
CN IX (glossopharyngeal)

Question 7

Derivatives of the 4th pharyngeal arch muscle & nerve

Answer 7

Cricothyroid, levator veli palatini, constrictors of pharynx
CN X (vagus)

Question 8

Derivatives of the 6th pharyngeal arch muscle & nerve

Answer 8

intrinsic muscles of larynx
CN X (vagus)

Question 9

4 stages of maturation of the lungs

Answer 9

pseudoglandular period
canalicular period
terminal sac period
alveolar period

Question 10

Pseudoglandular period

Answer 10

Weeks 5-17
By week 16, all major elements have formed except those with gas exchange.
No respiration possible

Question 11

Canalicular period

Answer 11

16-26 weeks
bronchi and terminal bronchioles become larger, lung tissue becomes highly vascular.
Respiration can happen but often doesn’t survive.

Question 12

Terminal sac period

Answer 12

24 weeks to late fetal period
Capillaries bulge into alveoli. Blood brain barrier is established, permits OK gas exchange is baby is born premature.
Surfactant expands the terminal sac

Question 13

Alveolar period

Answer 13

Late fetal stage to 8 years
Mature alveoli don’t form until after birth.

Question 14

What tissue gives rise to the respiratory system?

Answer 14

The endoderm lining the laryngotracheal groove

Question 15

How is fluid expelled from the respiratory tract at birth?

Answer 15

1. mouth and nose by pressure on fetal thorax
2. into the pulmonary capillaries
3. into the lymphatics and pulmonary arteries & veins

Question 16

Congenital malformations of the respiratory tract

Answer 16

TEF & RDS (hyaline membrane disease)

Question 17

Derivatives of the foregut

Answer 17

part of the fetus from the buccopharyngeal membrane to half of the 2nd part of duodenum

Question 18

What degree and direction is the longitudinal turn of the stomach?

Answer 18

90 degrees clockwise

Question 19

What is not a derivative of the foregut?

Answer 19

Spleen

Question 19

What does the dorsal mesogastrium become?

Answer 19

Omental bursa

Question 20

What does the ventral mesogastrium become?

Answer 20

septum transversum

Question 21

Development of the pancreas

Answer 21

2 pancreatic diverticula develop from foregut. 1 in ventral mesentery and 1 in dorsal mesentery

Question 22

Derivatives of the midgut

Answer 22

JAILED CATS
Jejunum
appendix
ileum
duodenum
cecum
ascending colon
transverse colon

Question 23

Derivatives of the hindgut

Answer 23

D RATS
Descending colon
rectum
anus
transverse colon
sigmoid colon

Question 24

How does the foregut get blood supply?

Answer 24

celiac trunk

Question 25

How does the midgut get blood supply?

Answer 25

superior mesenteric artery

Question 26

How does the hindgut get blood supply?

Answer 26

inferior mesenteric artery

Question 27

Explain midgut rotations

Answer 27

First - 90 degrees counterclockwise 2nd - large intestine returns, then further goes a 180 degree counterclockwise turn

Question 28

Order of development of the 3 sets of kidneys

Answer 28

Pronephroi mesonephroi metanophroi

Question 29

Congenital malformations of the GIT

Answer 29

Merkel's diverticulum Umbilical hernia - intestines push through abdominal wall, but skin still covers it Omphalocele - intestines failing to return to abdominal cavity

Question 30

What does mesonephroi become?

Answer 30

the epididymis

Question 31

What does metanophroi become?

Answer 31

the permanent kidney

Question 32

What tissues do the kidney develop from?

Answer 32

nephrogenic cord via intermediate mesoderm

Question 33

Gubernaculum in males vs females

Answer 33

Males - scrotal ligament Females - ovarian and round ligament

Question 34

The wolffian ducts

Answer 34

important role in male reproductive system

Question 35

The mullerian ducts

Answer 35

important role in female reproductive system

Question 36

What is the hormone for cardiovascular development

Answer 36

VEGA vascular endothelial growth factor

Question 37

which fold helps to from the heart tube?

Answer 37

lateral fold (folding)

Question 38

Where does the heart field form initially?

Answer 38

Cranilly, in the splanchnic mesoderm. This is the horseshoe shaped area.

Question 39

The fate of sinus venousus

Answer 39

Right horn forms smooth posterior wall. Left horn forms the coronary sinus. Left common cardiac vein forms the oblique vein

Question 40

When do chondrification centers develop?

Answer 40

Begins in 6th week

Question 41

Primary ossification centers

Answer 41

In the atlas (C1): 1 in the anterior arch 1 on each side in posterior arch In the axis (C2): 5 total

Question 42

which bones of the skull develop via intramembranous

Answer 42

Parietal and frontal

Question 43

which bones develop via endochondral

Answer 43

Occipital, sphenoid, ethmoid

Question 44

Congenital malformations of the skeletal system

Answer 44

achondroplasia - dwarfism hyperpituitarism - excessive GH acromegaly

Question 45

what tissue the skeletal system develops from

Answer 45

Mesenchyme

Question 46

what does mesenchyme differentiate into?

Answer 46

Osteoblasts - form bone Chondroblasts - form cartilage fibroblasts - form CT

Question 47

congenital malformations of the skeletal system

Answer 47

Spina bifida hemivertebra congenital scoliosis accessory ribs Achondroplasia

Question 48

Spina bifida

Answer 48

failure of neural arch halves to fuse together

Question 49

Achondroplasia

Answer 49

most common cause of dwarfism, affecting endochondral ossification

Question 50

Difference between intramembranous ossification and endochondral ossification

Answer 50

Intra - direct transformation of mesechymal tissue. Occurs in flat bones Endo - mesenchymal tissue first forms a hyaline cartilage model. Occurs in long bones

Question 51

Precursors to meninges

Answer 51

Dura mater - from mesoderm Arachnoid mater and Pia mater - from neural crest cells

Question 52

What tissue is the nervous system derived from

Answer 52

Ectoderm. Neural plate differentiates into neural tube (CNS) and neural crest (PNS)

Question 53

Development/zones of spinal cord

Answer 53

Ventricular zone - gives rise to neurons and microglial cells Intermediate zone - gray matter in spinal cord Marginal zone - white matter in spinal cord

Question 54

Primary brain vesicles

Answer 54

forebrain - prosencephalon midbrain - mesencephalon hindbrain - rhombencephalon

Question 55

Secondary brain vesicles

Answer 55

Forebrain - into telencephalon and diencephalon Midbrain - remains undivided Hindbrain - divides into mesencephalon and myelencephalon

Question 56

What is sulcus limitans?

Answer 56

Shallow groove that separates dorsal (alar) plate from the ventral (basal) plate

Question 57

Alar plate forms

Answer 57

afferent sensory neurons

Question 58

Basal plate forms

Answer 58

efferent motor neurons

Question 59

Which cells will develop into the PNS

Answer 59

Neural crest cells give rise to: Dorsal root ganglia ANS Schwann cells Enteric nervous system components