Brainscape's Knowledge GenomeTM

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


See full index

Head - 4 > embryology 3: development of midline structures > Flashcards

embryology 3: development of midline structures Flashcards

1
Q

where does the pituitary gland sit?

A

in the pituitary fossa of the sella turcica (deepest part of sphenoid bone - middle cranial fossa)

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

what is the pituitary gland?

A

a functional connection with the cerebellum and forebrain

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

what are the anatomical relations of the pituitary gland?

A

inferior to hypothalamus

hypophysis (hypothesis) + hypophysis cerebri (pituitary) - joined together by pituitary stalk

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

what is the posterior lobe of pituitary gland composed of?

A

neuroectoderm (collection of neurons)

neurohypophysis - modified neural tissue

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

where does the posterior lobe of the pituitary gland originate from?

A

infundibulum of the forebrain (downward outgrowth of diencephalon which grows toward the roof of the pharynx - CAUDALly)

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

where does the pituitary stalk originate from?

A

posterior lobe

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

what does the anterior lobe of the pituitary gland form from?

A

outpocketing of ectoderm of the stomatoderm called RATHKE’s POUCH
(stomatoderm forms body organs, and the pituitary gland is a glandular tissue)

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

where does the evagination of Rathke’s pouch for anterior pituitary come from?

A

roof of oropharynx primordial and grows DORSALly towards the developing brain

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

what happens to Rathke’s pouch?

A

pinches off from the ectoderm (outpocketing from stomatoderm) and becomes separated

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

what functionally links the anterior lobe of the hypothalamus and posterior pituitary lobe?

A

hypophyseal portal system

no need to enter systemic circulation

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

summary of origin of anterior and posterior lobes of the pituitary gland

A

anterior: endocrine organ (stomatoderm), Rathke’s pouch (outpocketing of ectoderm), grows up dorsally from roof of oropharynx
posterior: neuroectoderm (neural tissue), from infundibulum of forebrain, grows caudally towards roof of oropharynx

both linked by hypophyseal portal system

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

what happens after the anterior and posterior lobes grows towards each other?

A

they sit in the developing sphenoid bone as it ossifies to form the sella turcica (pituitary fossa)

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

where does the tongue receive contributions from?

A

all 5 arches

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

where does the tongue lie?

A

partly in the oral cavity and partly in the (oro)pharynx

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

what is the tongue comprised of?

A

extrinsic and intrinsic muscles

highly mobile, attached to floor of mouth via lingual frenulum

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

how is the tongue divided functionally?

A

anterior 2/3 and posterior 1/3

separated by sulcus terminalis with foramen cecum forming apex

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

when does the primordial of the tongue appear?

A

at the same time as the palate begins to form (palatal shelves of maxillary prominence)

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

what forms the pharyngeal floor?

A

from the fusion of ventral parts of the pharyngeal arches and pouches (endoderm)

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

what happens as the pharynx floor develops?

A

the tongue primordia receives a component from each of the pharyngeal arches where they meet in the midline

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

what is the tongue formed from?

A

2 lateral swellings (Ph A 1)

3 median swellings (PhA 1-4)

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

how can the median swellings of the tongue be further subdivided?

A

Median Ph 1 = tuberculum impar
median Ph 2,3,4 = cupola (slight Ph 4)
median Ph 4 = epiglottal swelling

22
Q

what happens to pharyngeal arch 1 in the development of the tongue?

A

the lateral lingual swellings (Ph A 1) overgrows the tuberculum impar (Ph A 1 median)

23
Q

what happens to cupola in the development of the tongue?

A

median Ph A 3 of cupola overgrows Ph A 2

24
Q

how does the development of the tongue allows high mobility?

A

further extensive degeneration (via apoptosis) of the tongue primordial, freeing it from the floor of the oral cavity, with lingual frenulum being remnant

25
Q

what is meant by children who are ‘tongue-tied’?

A

have a small lingual frenulum

majority of tongue still attached to the floor of the mouth

26
Q

what does Ph A 4 form?

A

cupola component = posteiror tongue

epiglottal swelling = epiglottis

27
Q

innervation of Ph A 4?

A

Ph A 4 = CN X

Ph A 4 tongue = superior laryngeal branch of vagus

28
Q

innervation of Ph A 1?

A

CN V
lingual nerve
(mandibular branch of trigeminal = CN V3)

29
Q

what is the mucosa of the anterior 2/3rd of the tongue derived from? therefore innervation?

A

Ph A 1 + 3 (3 overgrows 2 in cupola)

lingual (CN V3) and CN IX (glossopharyngeal)

30
Q

what are the innervations of the 4 parhyngeal arches of the tongue?

A 
1 = V
2 = VII
3 = IX
4 = X
31
Q

what is the mucosa of the posterior 1/3rd of the tongue derived from?

A

Ph A 3 (+4)
general + special sensory innervation = CN IX + X
(vagus innervates palatoglossus - extrinsic muscle of the tongue)

32
Q

where do taste buds develop?

A

in pupillae (nipple like structures on upper tongue)

33
Q

where do pupillae of the tongue develop from? innervation?

A

Ph A 2

CN VII - chorda tympani (taste buds - special sensory)

34
Q

where does the chorda tympani pass?

A

from Ph A 2 to Ph A 1, therefore crosses Ph pouch 1 (middle ear and eustachian tube) - therefore chorda tympani passes between malleus and incus

35
Q

how do intrinsic + extrinsic muscles of the tongue develop?

A

as myogenic precursors (muscle cells) from occipital somites (paraxial mesoderm) that migrate into the developing tongue

36
Q

innervation of the muscles of the tongue? (motor)

A 
hypoglossal nerve (CN XII)
(apart from palatoglossus - by CN X)
37
Q

where does the primordial of the thyroid gland appear?

A

thyroid diverticulum appears in in the floor of the pharynx between tuberculum impar and cupola (both median lingual swellings) - foramen cecum
(epithelial outgrowth giving rise to thyroid)

38
Q

what happens to the thyroid after thyroid diverticulum has appeared?

A

descents:
it migrates to its position in the anterior neck to pharyngeal gut (posterior), hyoid bone (superior) and laryngeal cartilages (superior)

39
Q

describe the descent of the thyroid gland

A

from foramen cecum (middle of sulcus terminalis)
proliferates + bifurcates
descends as BI-lobed diverticulum (connected by isthmus)

40
Q

what happens to the thyroid gland as it descends?

A

remains connected to the tongue by thyroglossal duct (patient connection between the tongue and the thyroid gland) - connects foramen cecum to thyroid gland

41
Q

what happens to the foramen cecum?

A

seals off and becomes a small indentation on dorsum of tongue

42
Q

what is the remnant of the thyroglossal duct?

A

pyramidal lobe

43
Q

when and where do thyroglossal cysts appear?

A

incomplete obliteration of the thyroglossal duct

commonly base of tongue, just inferior to hyoid

44
Q

what can thyroglossal duct give off?

A

ectopic thyroid tissue anywhere along the path of thyroglossal duct

45
Q

function of follicular cells of the thyroid gland and where are they derived from?

A

produce T3 + T4

from thyroid diverticulum (Ph A 2)

46
Q

what is the thyroid diverticulum?

A

cells which grew on the pharynx

which descends through foramen cecum

47
Q

where do the parafollicular cells of the thyroid gland derive from and what is their function?

A

produce calcitonin (PTH to regulate Ca2+)
derive from ultimobranchial body of Ph 4 pouch
(Ph 3 pouch for inferior parathyroid with thymus)

48
Q

what are the 2 sets of teeth humans have?

A

deciduous (baby) teeth

permanent teeth

49
Q

when do deciduous teeth appear? how many are there?

A

start to erupt about 6 months, fallout in childhood, replaced by permanent teeth
20 in total, does NOT have pre-molars

50
Q

when do permanent teeth appear? how many are there in total?

A

about 12 years, MOST permanent teeth erupted, EXCEPT 3rd MOLARS (wisdom teeth)
by about 21 years, ALL permanent teeth erupted (total 32)

Head - 4 (111 decks)

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