Brainscape's Knowledge GenomeTM

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


See full index

Physiology and Neuroscience Semester 1 > The Thyroid Gland > Flashcards

The Thyroid Gland Flashcards

1
Q

What shape is the thyroid gland?

A

Butterfly shaped

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

Where is the thyroid gland located?

A

Just inferior to the larynx

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

What is the thyroid gland composed of?

A

Right and left lateral lobes, one on either side of the trachea

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

What are the lateral lobe connected by?

A

Isthmus, anterior to the trachea

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

What is the third small lobe about 50% of thyroid glands have?

A

Pyramidal lobe, extends superiorly from the isthmus

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

What is the normal mass of the thyroid?

A

About 30g

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

What makes up most of the thyroid gland?

A

Thyroid follicles

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

What does the wall of each follicle consist of?

A

Primarily of cells called follicular cells, most of which extend to the lumen of the follicle

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

What surrounds each follicle?

A

Basement membrane

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

What happens when follicular cells are inactive?

A

Their shape is low cuboidal to squamous, but under the influence of TSH they become active in secretion and range from cuboidal to low columnar in shape

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

What two hormones are produced by follicular cells?

A

Thyroxine (T4- longer half life)

Triiodothyronine (T3- speedy)

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

What lies between cells?

A

Parafollicular cells (C cells)

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

What do C cells produce?

A

Produce the hormone calcitonin (CT) which helps regulate calcium homeostasis

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

What are the steps of the synthesis and secretion of T3 and T4?

A 
Iodide trapping
Synthesis of thyroglobulin
Oxidation of iodide
Iodination of tyrosine 
Coupling of T1 and T2
Pinocytosis and digestion of colloid
Secretion of thyroid hormones
Transport in the blood
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does the parathyroid gland do?

A

Produces different hormones

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

What actions of thyroid hormone?

A

Lung maturation in utero (surfactants)- easier breathing as lung more compliant
Bone maturation in infants
Neonatal brain development (proliferation, differentiation, synapse development)
Infant growth by enhancing growth hormone
Increased BMR to achieve calorigenesis
Increased in beta-adrenergic receptor quantity dilates resistance arterioles and sensitivity
Increased skeletal muscle contractility
Increased cardiac muscle contractility directly on Ca/Na exchange, increased heart rate, cardiac output, pulse pressure

17
Q

What is increased inotropic effect lead to?

A

Greater force of contraction

18
Q

What does increased chronotropic action lead to?

A

Greater speed

19
Q

What does increased lusitropic effect lead to?

A

Shorter diastolic relaxation time, all beta effects, diastolic pressure goes up

20
Q

What is the parathyroid hormone?

A

An 84 a.a. peptide produced by the chief cells of the parathyroid gland

21
Q

What do parathyroid hormone do?

A
  1. Fall in plasma Ca2+ detected by receptors on the parathyroid chief cells
  2. Parathyroid hormone (PTH) production increased
  3. PTH increases osteoclastic activity but these have no PTH receptors. Current idea is that o-blasts with PTH receptors recruit o-clasts
22
Q

What happens when bone is reabsorbed?

A

Calcium phosphate is set free. Plasma Ca2+ is therefore restored but there is a phosphate “leak”. Phosphate is lost in the urine both by increased filtration loss but also by reduced phosphate reabsorption. In addition, bicarbonate reabsorption is inhibited

23
Q

What is calcitonin?

A

A 32 a.a. peptide produced by the parafollicular cells of the thyroid gland: may act to increase calcium deposition in bones but maybe only during periods of physiological stress e.g. pregnancy. No diseases associated with excess or deficient production

24
Q

What are the steps of calcitonin production?

A
  1. Increased plasma Ca2+ detected by receptors on parafollicular cells
  2. Calcitonin production increased
  3. Calcitonin decreases osteoclastic activity
25
Q

What is relevant to bone mass in post menopausal changes?

A

Osteoclastic bone restoration is inhibited (i.e. put on more bone)

26
Q

What does osteoclast mean?

A

Breaking bone

27
Q

What does osteoblast mean?

A

Making bone

Physiology and Neuroscience Semester 1 (21 decks)

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