2.1 Thyroid-Normal Flashcards
Which lobe of the thyroid is typically bigger?
Right
The thyroid is encapsulated extends down to the ?
5th or 6th tracheal ring
Another term for the thyroid cartilage?
The Adam’s apple
The pyramidal lobe is a?
fetal remnant that some people have, skinny extension that extends superior from the isthmus
The size of the thyroid depends on (3)
Gender
Age
Body habitus/ Height
It is usually bigger in which gender?
Females
The usual length, Width and AP of the thyroid?
4-6cm
2 cm
2 cm
Out of the L x W x H (AP) which is the most precise/reproducible?
AP (2 cm)
The isthmus thickness is typically? (remember units)
2-6mm
One of the first places you may notice thickening/enlargement of the gland?
isthmus
The trachea is located ____ to the isthmus
posterior
The CCA and IJV is located____ and ____ to the thyroid?
Lateral ; posterior
The longus coli muscle is located?
posterior
The sternocleidomastoid muscle ? (2)
slightly anterior and lateral
The SCM (sternocleidomastoid muscles) are slightly ____ to the strap muscles. The strap muscles are ____ to thyroid
lateral; anterior
Compared to the thyroid Neurovascular bundle located
posterior
The 4 parathyroid glands and located ____ with 2 more ____ and 2 more ____.
Posterior; superior; inferior
The esophagus sits___ and slightly to the ____ of the thyroid
posterior; left
The Thyroid has a very rich_____ making it hard to biopsy
blood supply
The blood supply of the thyroid includes
Rt and Lt ?(2)
Inferior and Superior arteries
The Superior arteries are branches of the?
ECA
The Inferior arteries are branches of the?
Subclavian
The Thyroid is drained by 3 veins?
What are they and where do they drain?
Superior, middle in IVJ
inferior into innominate
Lymph drainage is from the?
Deep cervical lymph notes around the carotids.
*The lymph nodes around the thyroid are looked at with a neck sweep because?
It is THE MOST COMMON SITE FOR THYROID CANCER TO METASTASIZE
The sonographic appearance of the thyroid (3)
Homogeneous
Hyperechoic thin capsule
medium level echoes
The sonographic appearance of the Esophagus(2)
target appearance and peristalsis when patient swallows (good way to differentiate)
The sonographic appearance of the Trachea? (3)
Hyperechoic, curvilinear and shadowing
The sonographic appearance of the muscles (2)
hypoechoic with striations
What is the functional unit of the thyroid??
The follicle
The follicular cells produce the hormones (2)
T3 and T4
The lumen contains colloid which is?
thick gelatinous material that stores the T3 and T4 produced by the follicular cells
The parafollicular cells produce?
calcitonin - helps regulate the bloods calcium and phosphate levels.
What is the function of the thyroid?
Endocrine gland- makes, stores, secretes hormones
Regulates body metabolism
Produces T3, T4 and calcitonin
T3 and T4 affect?
Our metabolic rate
What is used to synthesize T3 and T4 from our diet?
Iodine
What maintains homeostasis of blood calcium?
Calcatonin
decreases concentration of blood calcium by inhibiting breakdown of bone
Maintenance of circulating T3 and T4 in the blood is a ___ feed back-system
Negative
A drop in T3 and T4 decreases our overall BMR (basal metabolic rate)
which triggers the hypothalamus to relase
TRH (thryotropin releasing hormone)
The TRH causing the release of ____ from the ____gland making more T3 & T4
TSH (thyroid stimulating hormone); pituitary
Thyroid disease can affect the amount of thyroid levels in the blood.
What is is called with normal thyroid levels?
Euthyroid
What is called when it is High or Low?
Hyperthyroid, Hypothyroid
Hypothyroidism decreases your ?
BMR
Hypothyroidism can be related to what 3 things?
Low Iodine
gland dysfunction
Pituitary gland abnormality
What are the S & S of hypothyroidism?
Weight gain Hair loss Lethargy Cold intolerance Husky voice
Causes of of Hypothyroidism (4)
Hashimoto’s
Iodine deficiency
Partial thyroidectomy (1 gland removed)
Pituitary gland problems
What is the most common cause of Hypothyroidism in North America?
Hashimoto’s
What is the most common cause of Hypothyroidism worldwide?
Iodine deficiency (poor diets in developing countries)
Hyperthyroidism increases BMR. can be causes by what 2 things?
Entire thyroid gland over functioning
or
Neoplasm that’s producing excessive amounts of thyroid hormone
What are the S & S of hyperthyroidism?(6)
Wt loss, increased appetite Nervousness Sweating, heat intolerance palpitations fatigue exophthalmos (eye bulging)
Causes of Hyperthyroidism include (5)
Grave's disease (with goiter) Toxic adenomas (benign masses, producing toxic amount of the hormone) Inflammation of the thyroid Excessive thyroid medication Pituitary tumors
Lab Tests with Hyperthyroid will have increased levels of ___ &____and decreased levels of ____
T3 and T4; TSH
Opposite with Hypothyroid
decrease T3 & T4 and increase TSH
Graves disease and Hashimoto are both? and produce?
Autoimmune disorders and produce thyroid antibodies that attack the thyroid
Other test that can be used to assess the thyroid
Nuc med scan -> determined function or sees nodules using radioisotope
Nuc med Hot nodules are
hyperfunctioning (most are benign)
Nuc med Cold nodules , don’t take up isotope
Non functioning (can have malignant potential)
still usually benign
What are some of the indications for performing a thyroid ultrasound (4)
Increase in gland size (symmetrical or not)
Changes in metabolism (Wt loss or gain)
Nuc med scan, showing cold nodule
palpable lump
Accurate hx includes
Medications Other diagnostic tests Previous surgery Family hx or palpable masses
What probe do you use to scan?
Highest frequency 12 or 18 MHz
