Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Neuro Exam 1 > Development of Pharyngeal Arches > Flashcards

Development of Pharyngeal Arches Flashcards

1
Q

What are the 4 components of the pharyngeal apparatus?

A

Pharyngeal arches
Pharyngeal pouches
Pharyngeal grooves (clefts)
Pharyngeal membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The pharyngeal arches develop early in the ____ week as ______ cells migrate from the neural tube into the future head and neck

A

4th; neural crest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

The 1st pair of arches, the primordial ______, appear as surface elevations lateral to the developing pharynx.

Arches ____- ___ soon appear as ridges on each side of the future head and neck regions.

The _____-____ arches are rudimentary and not visible on the surface of the embryo. The _____ arch may not form, or may quickly degenerate.

A

Jaws

2;4

5;6;5th

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Neural crest cells migrate to form the pharyngeal arches from what 3 initial brain divisions? The majority of neural crest contribution comes from which division?

A

Forebrain
Midbrain
Hindbrain (major contributor)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The hindbrain is divided into 7 segments called _______ which are what contribute the NCCs to the pharyngeal arches

A

Rhombomeres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Pharyngeal arch 1 receives streams of neural crest cells from which rhombomere(s)?

A

R1-2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Pharyngeal arch 2 receives streams of neural crest cells from which rhombomere(s)?

A

R4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Pharyngeal arches 3-4 receive streams of neural crest cells from which rhombomere(s)?

A

R6-7

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Which rhombomeres produce very few NCCs?

A

R3 and R5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Each pharyngeal arch consists of a core of ________, covered externally by _____ and internally by _______

A

Mesenchyme; ectoderm; endoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The mesenchyme core of the pharyngeal arches is derived from what type of cells?

A

The neural crest cells that migrate into the arches during the 4th week

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The pharyngeal arches support the lateral walls of the primordial ________. Neural crest cell migration into the first arch and differentiation into mesenchyme form the _____ and ______ prominences

A

Pharynx; maxillary; mandibular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

In the 5th week of development, after the first arch as separated into the maxillary and mandibular prominences, pharyngeal arch 2 overgrows 3 and 4, forming the ____ ______, an ______ depression that should disappear by the end of the 7th week (otherwise resulting in birth defects)

A

Cervical sinus; ectodermal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

In addition to forming the maxillary and mandibular prominences, NCC will form what other general pharyngeal arch components?

A

All connective tissue, including the dermis (integument), and smooth muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

________ _______ (paraxial) moves into each arch forming a central core of muscle primordium

A

Myogenic mesoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

_________ (from lateral plate mesoderm) differentiate into endothelium components of pharyngeal arches

A

Angioblasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Pharyngeal _______ plays an essential role in regulating the development of the arches

A

Endoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

A typical pharyngeal arch contains several structures:

An artery arises from the ____ ____ of the primordial heart, which passes around the primordial pharynx to enter the ____ _____.

A ______ _____forms the skeleton of the arch.

A muscular component differentiates into muscles in the head/neck. Sensory and motor nerves supply mucosa and muscles derived from each arch. Nerves are derived from the developing ____ which then grow into the arches

A

Truncus arteriosus; dorsal aorta

Cartilaginous rod

Brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Cartilage of pharyngeal arch 1

A

Meckel’s cartilage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Meckel’s cartilage = cartilage of PA1. Dorsal nodules of meckel’s cartilage break away to form the ____ and ______

A

Malleus; incus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Perichondrium of meckel’s cartilage (PA1) will form the ____ ____ of the malleus and _______ ligament

A

Anterior ligament; sphenomandibular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Ventral parts of meckel’s cartilage (PA1) will form the primordium of the ______, but this is just acting as a placeholder until the bone can form laterally and the cartilage disappears

A

Mandible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Cartilage of PA2

A

Riechert’s cartilage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Riechert’s cartilage (PA2) + an independent dorsal anlage will form the _____ as well as the _____ ____ of the temporal bone

A

Stapes; styloid process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

The cartilage between the styloid and the hyoid eventually regresses, and the perichondrium of Riechert’s cartilage (PA2) will form the ______ ligament

A

Stylohyoid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

The ventral end of Riechert’s cartilage (PA2) ossifies and forms what structure?

A

Lesser horn of hyoid bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

The third pharyngeal arch cartilage ossifies and becomes what structure?

A

Greater horn of hyoid bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What forms the body of the hyoid bone?

A

The hypopharyngeal eminence, which is a prominence in the floor of embryonic pharynx (from pharyngeal arches 3 and 4)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the fate of the 4th and 6th pharyngeal arches?

A

They fuse, forming laryngeal cartilages (except epiglottis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

T/F: the fifth arch has no derivatives

A

True

31
Q

Muscular components of pharyngeal arches are derived from what 2 sources?

A

Paraxial mesoderm

Prechordal plate

32
Q

What muscles and corresponding n. are associated with the first arch?

A

Muscles of mastication (CN V)

33
Q

What muscles and corresponding n. are associated with the second arch?

A

Stapedius and muscles of facial expression (CN VII)

34
Q

What muscles and corresponding n. are associated with the third arch?

A

Stylopharyngeus (CN IX)

35
Q

What muscles and corresponding n. are associated with the fourth arch?

A

Cricothyroid
Levator veli palatini
Pharyngeal constrictors

CN X

36
Q

What muscles and corresponding n. are associated with the sixth arch?

A

Intrinsic mm of the larynx (CN X)

37
Q

Each pharyngeal arch is supplied by its own cranial n. Special visceral efferents supply _____ derived from the arches. Special visceral afferents supply ______ and _______ of the head and neck.

A

Muscles; dermis; mucous membranes

38
Q

How does the trigeminal n. contribute to the pharyngeal arches?

A

Supplies the first arch

Principle sensory n. of head and neck — innervates face, teeth, mucous membranes of nasal cavities, palate, mouth, and tongue

Motor nerve for muscles of mastication

39
Q

How does the facial n. (CN VII) contribute to the pharyngeal arches?

A

Supplies 2nd arch

Muscles of facial expression

40
Q

How does the glossopharyngeal n. (CN IX) contribute to the pharyngeal arches?

A

Supplies 3rd arch

Stylopharyngeus m.

41
Q

How does the vagus n. (CN X) contribute to the pharyngeal arches?

A

Supplies 4th and 6th arches

4th arch is supplied by superior laryngeal branch of CN X and its recurrent laryngeal branch

Constrictos of pharynx (4th) and intrinsic mm of larynx (6th)

42
Q

The primordial pharynx is derived from _______ and widens cranially as it joins the _______, but narrows as it joins the esophagus.

________ of the pharynx lines the internal aspects of the pharyngeal arches as associated pouches

A

Foregut; stomodeum

Endoderm

43
Q

_____ pairs of pharyngeal pouches develop in a craniocaudal sequence between the arches

The first forms between the ___ and ____ arches

A

Five

1st; 2nd

44
Q

Which pair of pharyngeal pouches is rudimentary, if present?

A

5th pair

45
Q

Pharyngeal pouch endoderm contacts the ectoderm of pharyngeal grooves, which forms a double-layered ______ ________ which separates pouches from grooves

A

Pharyngeal membrane

46
Q

Pharyngeal membranes appear in the floors of the pharyngeal grooves, forming where the epithelia of the grooves and pouches meet. This area is quickly infiltrated and separated by mesenchyme, obliterating all but the _____ pharyngeal membrane, which combines with intervening mesenchyme to form the ____ _____

A

1st; tympanic membrane

47
Q

The epithelial lining of the pharyngeal pouches, which is ______ germ layer, forms important organs in the head/neck

A

Endoderm

48
Q

The first pharyngeal pouch expands into an elongated _____ ______. An expanded distal part of this structure contacts the 1st groove, contributing to part of the _____ _____ (the other part coming from the 1st pharyngeal membrane)

A

Tubotympanic recess; tympanic membrane

49
Q

The cavity of the tubotympanic recess formed by the first pharyngeal pouch forms the _____ ___ and _____ _____

The connection of the tubotympanic recess with the pharynx elongates, which forms the _______ _____

A

Tympanic cavity; mastoid antrum

Pharyngotympanic tube

50
Q

The second pharyngeal pouch is largely obliterated as the ____ ___ develops, BUT part of the cavity of this pouch remains as the ____ ____ (fossa), which is a depression between the palatoglossal and palatopharyngeal arches

A

Palatine tonsil; tonsillar sinus

51
Q

Endoderm of the second pharyngeal pouch proliferates - of which the central core will break down to form the ____ ______, the remainder will form surface epithelium of the tonsils and the lining of the above structure

Mesenchyme around the crypts differentiates into _____ tissue at 20 wks, later organizing into _____ _____ of the palatine tonsil

A

Tonsillar crypts

Lymphoid; lymphatic nodules

52
Q

The third pharyngeal pouch will expand and form a solid, dorsal bulbar part and a hollow, elongated ventral part.

By the 6th week, the epithelium of the dorsal bulbar part differentiates into the ______ _____ _____. Epithelium of the elongated ventral parts proliferates, obliterating the cavities. Portions then come together in the median plane to form the _______

Glands lose connections with the pharynx due to growth of brain and cardiac regions, resulting in caudal displacement of derivatives of 2nd-4th pouches

A

Inferior parathyroid glands; thymus

[note that the inferior parathyroid glands will separate from thymus at later stage]

53
Q

The fourth pharyngeal pouch expands and forms a dorsal, bulbar part as well as an elongated, ventral part.

By the 6th week, epithelium of dorsal bulbar part differentiates into a ____ ____ ____ which lies on the dorsal surface of the thyroid gland.

The fourth pouch also gives rise to the _____ body

A

Superior parathyroid gland

Ultimopharyngeal

54
Q

Pharyngeal ______ separate the pharyngeal arches and are separated externally. They are numbered 1-4 from cranial to caudal and arise during the 4th-5th weeks.

The first pair persists as the _____ ____ _____

Pairs 2-4 lie in the ____ ____, a slit-like depression, and should be obliterated by the 7th week as the neck develops.

A

Grooves

External acoustic meatus

Cervical sinus

[note that birth defects of 2nd groove are common]

55
Q

Remnants of cervical sinus and/or the 2nd pharyngeal groove which persist and form a spherical/elongated cyst d/t collections of epithelial debris and fluid

A

Cervical (branchial) cysts

56
Q

Cervical (branchial) cysts often lie free in the neck, inferior to the angle of the ______; they also occur along the anterior border of the ____ m.

They are apparent until late childhood/early adulthood as slowly enlarging, painless swellings in the neck; also possible that they remain patent as fistulas or periauricular openings

A

Mandible; SCM

57
Q

What is the first endocrine gland to develop, at 24 days post fertilization?

A

Thyroid primordium

58
Q

Thyroid primordium forms from a median ______ thickening in the floor of the primordial pharynx. It descends into the neck with tongue growth and passes ____ to the developing hyoid bone and _______ cartilages

It is connected to the tongue by a narrow tube called the ______ duct

A

Endodermal; ventral; laryngeal

Thyroglossal

59
Q

At 7 wks, the thyroid starts out as a small mass of endodermal cells which are broken up into epithelial ____ by vascular mesenchyme. At this point the thyroglossal duct has normally degenerated, except for the proximal opening which persists as the _____ ____ on the dorsal tongue. The _______ lobe is variably present and extends superiorly from the isthmus in 50% of people

A

Cords; foramen cecum; pyramidal

60
Q

By the 10th week, the epithelial cords of the future thyroid have divided into cellular groups and a lumen. The cells are arranged into a single layer around thyroid _______

At the 11th week, colloid appears and synthesis of ____ occurs

At 20 weeks, levels fetal ____ and _____ increase

At 35 weeks, levels of the above 2 hormones reach adult levels

A

Follicles

TH

TSH; thyroxine

61
Q

The elongated ventral part of the 4th pharyngeal pouch forms the _____ ____ which fuses with the thyroid gland

Cells disseminate within the thyroid and form ______ cells (derived from _______ cells), which produce calcitonin (lowering blood Ca)

A

Ultimopharyngeal body

Parafollicular; neural crest

62
Q

Malformation of eyes, ears, mandible, and palate which together constitute ____ ____ syndrome

A

First arch

63
Q

What general developmental event causes first arch syndrome?

A

Insufficient migration of NCCs into the 1st arch during the 4th week

64
Q

Describe treacher collins syndrome

A

First arch syndrome that is also called mandibulofacial dysostosis

Characterized by malar hypoplasia with down-slanting palpebral fissures, defects of lower eyelids, deformed external ears and sometimes other ear structures

Autosomal dominant; mutations in TCOF1 which encodes TREACLE protein involved in ribosome biogenesis —> increased apoptosis of cranial NCCs

65
Q

What first pharyngeal arch syndrome typically occurs de novo and is associated with hypoplasia of the mandible, cleft palate, and defects of the eyes and ears?

A

Pierre Robin sequence

66
Q

What is the initiating defect in Pierre robin sequence?

A

Small mandible (micrognathia) —> results in posterior displacement of the tongue and obstruction of full closure of the palate resulting in bilateral cleft palate

67
Q

Absence of a thyroid gland or one of its lobes

A

Thyroid agenesis

68
Q

Unilateral failure of thyroid formation

A

Thyroid hemiagenesis

69
Q

Which lobe of the thyroid is more commonly absent in thyroid hemiagenesis?

A

Left lobe

[mutations in the receptor for TSH are likely involved]

70
Q

What syndrome is characterized by agenesis of thymus and parathyroid glands, congenital hypoparathyroidism, shortened philtrum of upper lip, low set ears, nasal clefts, thyroid hypoplasia, and cardiac abnormalities?

A

DiGeorge syndrome

71
Q

The aortic arch artery system initially consists of 5 pairs of arteries that arise from the ____ ____. These are remodeled to form great arteries of the thorax and branches that supply the head/neck.

The common and internal carotids are the ____ arch arteries.

The distal internal carotids are extensions of the ____ ____

The external carotids form de novo from the ___ ____

A

Aortic sac

3rd

Dorsal aorta

Common carotids

72
Q

Endothelium of the head vasculature and aortic arch arteries arises from what germ layer?

A

Mesoderm

73
Q

Histogenesis of parathyroid glands: epithelium of the dorsal parts of the ___ and ____ pouches proliferates in 5th week. Small nodules form on dorsal aspect of each pouch. Vascular _____ invests and forms capillary network. ______ cells differentiate during the embryonic period, secreting PTH, which regulates fetal Ca metabolism. ____ cells differentiate at 5-7yrs of age

A

3rd; 4th; mesenchyme; Chief (principal); oxyphil

74
Q

Histogenesis of the thymus: thymic primordium develops from epithelial cells derived from endoderm of 3rd pair of pouches. Epithelial tubes grow into mesenchyme and become solid cords that proliferate, forming side branches. Each side branch becomes the core of a lobule of the thymus. Some epithelial cords become arranged around a central point, forming ____ _____. Other epithelial cords spread apart, but keep their connections to form an epithelial ______, which will be invaded by lymphocytes. Growth and development of the thymus are not complete at birth, and will actively contibue during childhood until it eventually involutes

A

Thymic corpuscles (Hassall corpuscles); reticulum

Neuro Exam 1 (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions