Thyroid Gland Flashcards
Location of thyroid gland
anterior part of the front and sides of the neck
right and left lobes of thyroid gland are United by——-
an isthmus
——- may project upwards from the isthmus or ———
A 3rd pyramidal lobe
from one of the lobes.
Origin and insertion of the Levator glandulae thyroidae of——-
Soemmerring
from the body of the hyoid bone to the pyramidal lobe or isthmus to elevate the thyroid gland
Vertebral level of the levator glandular thyroidae is ——?
C3-C5
The word thyroid means ——
Shield-like
Location of Accessory thyroid glands
found as small detached masses of thyroid tissue in the vicinity of the lobes or above the isthmus
Hormones produced by thyroid glands are —?
Thyroxine, thyrocalcitonin
- stimulates psychic growth
Thyroxine
Vertebral level of :
upper border of thyroid lobe
Lower border of thyroid lobe
C5-T1
Thyroid gland extends from the middle of the———- to the ——-tracheal ring
thyroid cartilage
4th or 5th
isthmus covers the ——tracheal rings
2nd to 3rd
Length, width and breadth of the lobe of the thyroid
Lobe-5cm by 2.5cm by 2.5cm
Lengtha and width of the isthmus of the thyroid
Isthmus-1.2cm by 1.2cm
Weight of thyroid gland
25g
Male or female, which one has a larger Thyroid gland ?
Female
How many tracheal rings does the trachea have
15
How many capsule of thyroid do we have???
List them
True and false capsule
true capsule of the thyroid gland is formed by——-
false capsule of the thyroid gland is formed from ——-
peripheral condensation of the connective tissue of the gland
the pretracheal layer of the deep cervical fascia
capsule of the thyroid gland is thin—- but thick in the——
posteriorly
interior
——- connects the lobe of the thyroid gland to the ——-
Suspensory ligament of berry
cricoid cartilage.
Difference between the capsules of the thyroid gland and prostate gland
for thyroid gland: veins are between gland and true capsule;plane of cleave is between true and false capsule
-for prostate gland: veins are between true and false capsule;plane of cleavage is between gland and true capsule
the thyroid is removed along with ———capsule
True capsule
Relations of the lateral surface of the thyroid gland
sternohyoid,sternothyroid, superior belly of the omohyoid, ant. border of the sternomastoid
Relations of the medial surface of the thyroid gland
2tubes : trachea and esophagus
- 2 muscles the inferior constrictor and cricothyroid
- 2 nerves- the external laryngeal and recurrent laryngeal nerves
Posterolateral relations of the thyroid gland
the carotid sheath and overlaps the carotid artery.
Apex of the thyroid gland is Limited superiorly by the——-
attachment of the sternothyroid to the oblique line of the thyroid cartilage.
The isthmus is always present. T/F
F. occasionally absent
Anterior relations of the isthmus of the thyroid gland
covered by right & left sternothyroid and sternohyoid muscles, the anterior jugular veins& fascia
Posterior relations of the isthmus
Tracheal rings(2-3) May be lower or higher
What is the arterial supply of the thyroid gland
superior and inferior thyroid arteries
superior thyroid artery runs intimately with —— at its ——
ext. laryngeal nerve.
Front
superior thyroid artery runs in what direction from origin?
runs downwards and forwards
List the branches of the superior thyroid artery
Hyoid artery, Sternocleidomastoid artery, Superior laryngeal artery,and Cricothyroid artery
The superior thyroid artery pierces the——— to reach the——- where it———
pretracheal fascia
upper pole of the lobe
divides to give anterior and posterior branches
Fate of Anterior and posterior branch of superior thyroid artery
anterior branch of STA descends on the anterior border of the lobe and continues along the border of the isthmus to anastomose with its fellow of the opposite side.
The posterior branch of STA descends on the posterior border of the lobe to anastomose with the ascending branch of the inferior thyroid artery.
Inferior thyroid artery runs in what direction from origin?
runs upwards, medially, then downwards to reach lower pole of the gland
Inferior thyroid artery is——- to carotid sheath and the——- but——— to vertebral vessels
posterior
middle cervical sympathetic ganglion
anterior
List the branches of the inferior thyroid artery :
the inferior laryngeal, the oesophageal, the tracheal, the ascending cervical and the pharyngeal arteries
——- part of the inferior thyroid artery is intimately related to the——— found at its ——-
Terminal
recurrent laryngeal nerve.
Front
Inferior thyroid artery divides into ——-which pierce the fascia separately to reach the ——part of the gland
4 or 5 glandular branches
lower
superior thyroid artery supplies the superior third of the lobe and upper half of the isthmus .
T/F
T
The superior thyroid vein drains into the——- or in the——
internal jugular vein
facial vein.
The middle thyroid vein emerges from ———and soon drains into the——
the middle of isthmus
internal jugular vein.
Inferior thyroid veins emerge at the—— and forms a—— in front of the ——- that drains into the——-
lower part of the isthmus
plexus
trachea
left brachiocephalic vein.
A fourth thyroid vein of——- may occur between the ———and drain into the——-
Kocher
middle and inferior veins
internal jugular vein.
Popular places known for with iodine deficiency
Switzerland
-VietnaM
Enlarged thyroid is called ——
Goiter
—— goiter is common in Nigeria and is due to ——
Endemic
No iodine in salt
Normal anatomy of the recurrent laryngeal nerve is for the right to ——- and the left to ———
- on the right side the recurrent laryngeal nerve hooks around behind the subclavian artery
- on the left side this nerve passes around behind the aortic arch before ascending in the neck.
in a vascular anomaly of the right subclavian artery, the recurrent laryngeal nerve ——-around this artery.
-It proceeds from the vagus nerve in a more——— to the larynx.
no longer “recurs”
transverse direction
The non-recurrent laryngeal nerve is more common to which side?…left or right
more common on the right than on the left
During operation the superior thyroid artery is ligated——- the gland to save the external laryngeal nerve and the inferior thyroid artery is ligated——- from the gland to save the recurrent laryngeal nerve
near
away
What lymph nodes drain the thyroid gland
upper deep cervical lymph nodes
lower deep cervical nodes
Indirect routes of the lymph nodes draining the thyroid gland is????
Upper: through the prelaryngeal nodes
Lower: through the pretracheal and paratracheal nodes.
Sympathetic nerve supply of the thyroid gland ??
mainly from the middle cervical ganglion and partly also from the superior & inferior cervical ganglia.
ParaSympathetic nerve supply of the thyroid gland ??
recurrent and superior laryngeal nerves
List the 2 secretory cells in the thyroid gland
Follicular cells
Parafollicular cells:
Location of the secretory cells in the thyroid gland
Follicular cells:
-lining the follicles of the thyroid
Parafollicular cells:
-lie in between the follicles
What does each secretory cell in the thyroid gland secrete
Follicular cells:triiodothyronine and tetraiodothyronine(thyroxine)
Parafollicular cells: secrete thyrocalcitonin
Development of thyroid gland starts when???
Day 24
first endocrine gland to develop is ——?
Thyroid gland
Thyroid gland develops from a——-grows down in front of the neck from the floor of the primitive pharynx just beneath——.
- lower end of the diverticulum ———.
- The rest of the diverticulum remains narrow and is known as the——., which soon disappears and it’s upper end is marked by the——-, it’s lower end persists as the——-
median endodermal thyroid diverticulum
tuberculum impar
enlarges to form the gland.
thyroglossal duct
foramen caecum
pyramidal lobe
Remnants of the thyroglossal duct may form——-
thyroglossal cysts or thyroglossal fistula
Thyroid tissue may develop at abnormal sites along the course of the duct resulting in——— and absence of thyroids in the normal location
lingual or retrosternal thyroids.
What is myxedema
Myxedema is another term for severely advanced hypothyroidism
Hypothyroidism causes—— in infants and——- in adults.
cretinism
myxoedema
Benign tumours of the gland may ——-neighbouring structures, like the carotid sheath, the trachea, etc.
displace and even compress
Malignant growths tend to——- neighbouring structures.
invade and erode
largest endocrine gland of the body is ——
Thyroid gland
The thyroid gland moves up and down during swallowing .
T/F
If T, why
If F , why
T.
because its capsule is attached to laryngeal cartilages and hyoid bone, which moves up and down during swallowing. Thus thyroid swellings can be distinguished clinically from other swellings in the region of the neck.
What is Thyroidea ima artery
It is a branch of the brachiocephalic trunk or may arise directly from the arch of aorta. It enters the isthmus from below.
Present in only 30% of the cases
Which brachiocephalic vein does the inferior thyroid vein drain into?
Left
Thyroid gland reaches its final destination in development by week -?
End of 7th week
The thyroid gland becomes functional by —
3rd month
Thyroid gland assumes it’s definitive shape by ___ week
7th
Agenesis of thyroid gland usually involves its ____ lobe
Left
