Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Cranio Exam 3 > development of thyroid gland, tongue, and ear > Flashcards

development of thyroid gland, tongue, and ear Flashcards

1
Q

what is the first endocrine gland to develop in the embryo?

A

thyroid gland

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

when does thyroid gland development begin?

A

24 days after fertilization

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

the thyroid gland develops from a median endodermal thickening in the ___________

A

floor of a primordial pharynx

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

thyroid primordium

A

small outpouching that develops from the thickening in the floor of the primordial pharynx

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

the thyroid primordium comes from which pharyngeal pouch?

A

2nd

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

thyroglossal duct

A

narrow tube connecting the thyroid gland to the tongue that eventually dissolves

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

how are the two lobes of the thyroid gland connected?

A

isthmus of the thyroid gland

-lies anterior to the developing second and third tracheal rings

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

by what week does the thyroid assume definitive shape and reach its final site in the neck?

A

seventh week

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

the thyroglossal duct has normally degenerated by what week?

A

seventh week

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

foramen cecum

A

the proximal opening of the thyroglossal duct that persists

-small pit in tongue

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

the pyramidal lobe extends upward from the isthmus in about _____% of people

A

50%

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

levator of thyroid gland

A

fibrous tissue or smooth muscle that attaches the pyramidal lobe to the hyoid bone

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

the pyramidal lobe and associated smooth muscle represent a persistent part of the distal end of the _____

A

thyroglossal duct

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

site of origin of thyroglossal duct between floor of branchial arches 1 and 2

A

foramen cecum

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

what does the thyroid primordium consist of?

A

solid mass of endodermal cells

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

what does the cellular aggregation of the thyroid primordium break up into?

A

a network of epithelial cords

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

by what week do the cords divide into small cellular groups?

A

10

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

what forms in each cell cluster of the thyroid when the cells become arranged in a single layer?

A

lumen

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

what happens during the 11th week in thyroid development?

A

colloid begins to appear in each cell called thyroid follicles and iodine concentration and synthesis of thyroid hormones can be demonstrated

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

thyroid secretion reaches adult level by how many weeks?

A

35 weeks

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

congenital hypothyroidism (cretinism)

A

most common metabolic disorder in neonates

-common cause of intellectual disability

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

causes of congenital hypothyroidism

A

agenesis–failure of normal development of thyroid gland

ectopic thyroid–situated in a different location (e.g. beneath tongue)

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

signs and symptoms of congenital hypothyroidism

A
  • retarded physical and mental growth
  • spine curved and height is less than 3 ft
  • head is large with wiry hair
  • thick eyelids and large tongue
  • abdomen protruding and sexual maturity not seen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

treatment of congenital hypothyroidism

A

levothyroxine given to children

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
ectopic thyroid
thyroid develops in abnormal position -mostly along course of thyroglossal duct 1/4000 people
26
most common site for ectopic thyroid
lingual
27
accessory thyroid gland tissue is--
lateral to thyroid cartilage
28
anomalies related to thyroglossal duct
cyst sinus fistula
29
t/f the thyroglossal duct disappears
true
30
what causes a thyroglossal cyst?
remnant of duct persists and forms a cyst in the tongue or anterior neck
31
thyroglossal cyst
painless, progressively enlarging, moveable mass - observed at 5 yrs - inferior to hyoid bone - may contain thyroid tissue
32
thyroglossal duct sinus
following infection of a cyst perforation of the skin opens in the median plane of the neck, anterior to the laryngeal cartilages
33
thyroglossal duct may remain patent and open into external surface causing a ---
fistula
34
arch development of tongue
arch 1-- oral part of tongue (anterior 2/3) arch 2--initial contribution to surface is lost arch 3--pharyngeal part of tongue (posterior 1/3) arch 4--epiglottis and adjacent regions
35
development of anterior 2/3 of tongue
- 3 swellings from 1st arch - proliferation of mesenchyme in ventromedial parts of the 1st pair of pharyn arches - median tongue bud (elevation) appears in floor of primordium pharynx near end of 4th week, just in front of foramen cecum--> swelling is first indication of tongue - 2 oval distal tongue buds develop on each side of the median tongue bud
36
what grows over the median tongue bud?
lateral tongue buds increase in size and merge together overgrowing the median tongue bud
37
what forms the anterior 2/3 of the tongue?
merged distal tongue buds
38
how is the fusion of the distal tongue bud indicated?
a middle groove, the median sulcus of the tongue and internally by fibrous lingual septum (median tongue bud forms no recognizable part of the adult tongue)
39
2 elevations that develop caudal to the foramen cecum to form the posterior 1/3 of tongue?
1. copula: forms by fusion of ventromedial part of the 2nd pair of pharyngeal arches 2. hypopharyngeal eminence: develops caudal to the copula from mesenchyme in ventromedial parts of the 3rd and 4th pairs of pharyngeal arches
40
what happens to the copula as the tongue develops?
gradually overgrown by the hypopharyngeal eminience and disappears
41
the pharyngeal part of the tongue develops from what?
the remaining part of the hypopharyngeal eminence
42
terminal sulcus
line of fusion of anterior and posterior parts of tongue | -v shaped
43
pharyngeal mesenchyme
connective tissue and vasculature of tongue
44
occipital myotomes
most of tongue muscles from myoblasts that migrate from occipial mytomes
45
innervates tongue muscles as they develop
hypoglossal nerve (XII)
46
the entire tongue is within the mouth at birth, its posterior third descends into the oropharynx by ----- yrs old
4
47
tongue muscles are from ______ occipital myotomes
3,4,5
48
lingual papillae appear toward the end of the ---- week
8
49
what kind of nerve endings do lingual papilla contain
afferent nerve endings
50
what papilla appear first
vallate and foliate | close to the terminal branches of glossopharyngeal nerve IX
51
filiform papillae
most common threadlike shape develp during early fetal period (10-11 wks)
52
when do fungiform papillae form?
later near termination of chorda tympani branch
53
when do taste buds develop
11-13 wks by active interaction bw epithelial cells of tongue and invading gustatory cells from chorda tympani and glossopharyngeal and vagus nerves
54
when is there a fetal response to bitter taste?
26-28 weeks
55
anterior 2/3 of tongue nerve supply
lingual branch of mandibular division of trigeminal
56
taste for anterior 2/3
chorda tympani except vallate papillae which are innervated by glossopharyngeal nerve (IX)
57
motor for anterior 2/3
hypoglossal
58
common sensation of tongue
trigeminal
59
nerve of 1st pharyngeal arch and this arch forms the median and distal tongue buds
trigeminal
60
nerve of second phar arch
facial
61
palatoglossus is supplied by?
vagus
62
the posterior 3rd of tongue is innervated by ?
glossopharyngeal from 3rd arch
63
superior laryngeal branch of vagus supplies?
small area of tongue anterior to epiglottis
64
the vagus nerve is of the --- arch
4
65
all muscles of the tongue are supplied by _____ except for _____
all by hypoglossal except palatoglossus which is supplied from pharyngeal plexus by fibers from vagus nerve
66
aglossia
no tongue | feeding, breathing, and speech issue
67
bifid tongue
failure of fusion of 2 lateral lingual swelling
68
congenital lingual cyst of fistula
persistent lingual part of thyroglossal duct
69
tongue tie (ankyloglossia)
short, thick band of tissue which connects the lip of tongue to floor of mouth and restricts movement of tongue
70
microglossia
small tongue | -with microgenitalia and limb defects
71
macroglossia
large tongue - trisomy 21 - acromegaly - mucopolysaccharidoses - congential hypothyroidism - diabetes
72
3 anatomical parts of ear
1. external --auricle, external auditory meatus, outer layer of tympanic membrane 2. middle--3 auditory ossicles (stapes, incus, malleus), inner layer of tympanic membrane 3. internal--vestibulocochlear organ (cochlea and semicircular canal)
73
external auditory canal develops from--
surface ectoderm that covers the dorsal end of the 1st pharyngeal groove
74
meatal plug
solid epithelial plate that develops at bottom of funnel shaped pharyngeal groove
75
what lines the middle ear?
1st pharn pouch endoderm
76
eustachan tube
connects pharynx to ear
77
malleus and incus form from the mesoderm of the --- arch
1st arch | mechel's cartilage
78
stapes forms from
mesoderm of 2nd arch | reichert's cartilage
79
ossicles are full sized by ____
15 weeks
80
ossicles ossify by
25 weeks
81
tensor tympani supplied by ---
mandibular nerve (1st arch)
82
stapedius supplied by
facial nerve (2nd arch)
83
the first brachial arch is also called
mandibular arch
84
second arch is called
hyoid arch
85
in between 1st and 2nd brachial arch is called the
ectodermal cleft
86
ectoderm of internal ear
membranous labyrinth
87
bony labyrinth
mesoderm of internal ear
88
what happens in the 3rd week of internal ear development?
surface ectoderm--otic placode invaginates into otic pit
89
4th week in ear development
pit edges fuse to become otic vesicle (primordium of membranous labyrinth)
90
otic vesicle separates from surface ectoderm, elongates, and forms the _____
endolymphatic duct and sac
91
dorsal utericular part of ear
forms endolymphatic and semicircular ducts and utericle
92
ventral saccular part of ear
forms saccules and cochlear duct
93
congenital deafness
inner ear deafness (rubella) | middle ear deafness, anomalies of 1st and 2nd arches
94
auricular anomalies of ear
accessory auricle, absence of auricle, small auricle
95
atresia of external auditory meatus
failure of canalization
96
congenital cholestotoma
keratin filled cysts that grow medial to tympanic membrane result either from birth abnormality, trauma or metaplasia
97
what criteria do conditions need to fulfill in order for them to be a congenital ear disorder?
1. mass medial to tympanic membrane 2. normal tympanic membrane 3. no previous history of ear discharge, perforation, or surgery

Cranio Exam 3 (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions