Endocrine Tissues

Question 1

Give 6 examples of endocrine glands and their hormones.

Answer 1

Anterior pituitary (TSH, FSH, ACTH, LH)
Posterior pituitary (ADH and oxytocin)
Thyroid (Thyroxine (T4) and triodothyroinine (T3) and calcitonin)
Parathyroid (PTH)
Adrenal glands (corticosteroids, androgen, estrogen, progestin, adrenaline)
Pancreas (glucagon by alpha, insulin by beta)

Question 2

What other parts of the body contain endocrine tissues? Give examples of hormones

Answer 2

A lot of organs do:
Heart (atrial natriuretic factors)
Stomach (Ghrelin, Gastrin, Leptin)
Liver (angiotensin, thrombopoeitin)
Duodenum (Secretin)
Kidney (Renin, Erythropoeitin, Thrombopoeitin)

Question 3

What are the 4 main types of hormones? Give an example of each

Answer 3

Peptide hormones (Insulin)
Steroid hormones (Androgens, oestrogen)
Catecholamines (Adrenaline)
Thyroid Hormones (T4, T3)

Question 4

What are the main differences between the types?

Answer 4

All of them are made in advance except for steroid hormones which are made on demand.
Peptide hormones and catecholamines have the receptors that will interact with the hormone on the cell membrane because they can’t diffuse.
Steroid hormones and thyroid hormones have the location of the receptor on the nucleus of the cell or somewhere in the cytoplasm.

Question 5

Why is the hypothalamus important?

Answer 5

Because it is central to homeostasis.
It deals with thermoregulation
Heart rate
Blood pressure
Stimuli from the autonomic nervous system etc...

Question 6

How is the portal system special? What does it look like?

Answer 6

It is special because it has a portal vessel connecting two capillary beds.

Question 7

Why is there always a small concentration of pituitary hormones in the blood?

Answer 7

Because they are subject to both constitutive and regulated merocrine secretion.

Question 8

Where can the thyroid gland be found and what does it look like?

Answer 8

Anterior to the trachea and it looks like a butterfly.

Question 9

What hormones does the thyroid gland secrete?

Answer 9

TSH, T3, T4.

Question 10

What condition is related to a low level of TSH and an elevated level of T3 and T4?

Answer 10

Hyperthyroidism

Question 11

What condition is related to a high level of TSH and a low level of T3 and T4?

Answer 11

Hypothyroidism

Question 12

What can be concluded when a patient with hypothyroidism also present with Anti-TPO and anti TG in the blood?

Answer 12

That the patient has Hashimoto’s.

Question 13

What can be concluded when a patient with hyperthyroidism also present with TSI and anti-TSH?

Answer 13

That the patient has Grave’s

Question 14

What are parafollicular cells? What are their functions?

Answer 14

Follicular cells in the thyroid that are between the main follicular cells.
They produce and store calcitonin

Question 15

What is the role of calcitonin?

Answer 15

When calcium levels are high in the plasma calcitonin is released to inhibit osteoclasts from breaking down bone. This means that more osteoblasts lay down bone than osteoclasts break down.

Question 16

What is the main role of the parathyroid gland?

Answer 16

To monitor plasma calcium concentrations.

When plasma concentration is low the parathyroid secrete PTH. PTH indirectly causes an increase in osteoclasts activity.

Question 17

How can parathyroid disease be very serious?

Answer 17

Since calcium is the most important element for the nervous system, skeletal and muscular system an over production of PTH will lead to high blood calcium. This can cause symptoms in brain, muscles and bones.
Also a non-functioning parathyroid means that PTH is not secreted and may lead to a lower level of calcium in blood. PTH is essential for life, calcitonin is not.

Question 18

What are the shapes of the adrenal glands and where can they be found?

Answer 18

On top of the kidneys. The left on is crescent shaped and the right one is pyramidal.

Question 19

What two parts are adrenal glands made of?

Answer 19

The cortex and the medulla.

Question 20

What is the medulla made of? What do they secrete?

Answer 20

Chromaffin cells that secrete adrenaline and noradrenaline.

Question 21

What makes chromaffin cells special?

Answer 21

Numerous of myelinated presynaptic sympathetic nerve fibres pass directly to the chromaffin cells. They are considered the equivalent of postsynaptic neurons.

Question 22

What are the three layers of the adrenal cortex? What do the different layers secrete?

Answer 22

Outer - Zona glomerulosa (Aldosterone)
Middle - Zona fasciculata (cortisone and cortisol)
Inner - Zona reticularis (androgen precursors)

Question 23

Define stress

Answer 23

A state of real or perceived threat to homeostasis

Question 24

What does the cortex secrete and what is its origin?

Answer 24

Corticosteroids and mesodermal origin.
Zona glomerulosa
Zona fasciculata
Zona reticularis

Question 25

What does the medulla secrete and what is its origin?

Answer 25

Catecholamine hormones and has an ectodermal neural crest origin
Chromaffin cells

Question 26

What are the behavioural changes of stress response?

Answer 26

Increased awareness
Improved cognition
Euphoria
Enhanced analgesia

Question 27

What are the physiological adaptations of stress response?

Answer 27

Increased cardiovascular tone
Increased respiratory rate
Increased intermediate metabolism
Decreased feeding, digestion, growth, reproduction and immunity

Question 28

What makes the pancreas special as an organ/gland?

Answer 28

That it is both exocrine and endocrine. It produces enzymes such as lipase, trypsinogen, amylase, elastase etc…
It produces hormones such as glucagon (alpha) and insulin (beta), secretin, ghrelin, gastrin etc…

Question 29

What is the structure of the pancreas glands?

Answer 29

Alveolar glands grouped into lobules that contain numerous zymogen granules. Connect through intercalated ducts into the pancreatic duct which joins with the bile duct to form the common bile duct.