S1: Overview to Endocrinology Flashcards

1
Q

List some major endocrine glands/organs in the body

A
Hypothalamus
Pituitary Gland
Thyroid
Adrenal
Pancreas
Parathyroid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What forms the hypothalamic-pituitary axis?

A

Hypothalamus

Pituitary Gland

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

What major endocrine structures are regulated by the hypothalamic-pituitary gland?

A

Thyroid

Adrenal cortex/medulla gonads

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

What regulates the pancreas and parathyroid glands?

A

They are regulated by other controlled variables e.g. insulin in pancreas and glucagon, which are dependent on glucose levels, parathyroid regulate calcium levels

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

What structure is responsible for releasing and inhibiting hormones?

A

Hypothalamus

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

What hormones does the thyroid gland release?

A

Thyroxine

Triidothyronine

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

What hormones does the adrenal glands release?

A

Adrenal Cortex: Cortisol and Aldosterone

Adrenal Medulla: Adrenaline and Noradrenaline

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

What hormones does the gonads release?

A

Oestrogens
Androgens
Progestagens

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

What hormones does the pancreas release?

A

Insulin

Glucagon

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

What hormone does the parathyroid gland release?

A

Parathyroid hormone

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

GIve examples of other tissue releasing hormones

A

kidneys (vitamin D, EPO), CVS (ANP, endothelins), pineal gland (melatonin), thymus gland (thymic hormones), bone (phosphate) and adipose tissue (leptin).

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

What are the 4 types of signalling mechanisms?

A
  1. Endocrine
  2. Paracrine
  3. Autocrine
  4. Intracrine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does endocrine mean?

A

Hormones are released by an endocrine cell into the general circulation and act on distant target sites

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

What does paracrine mean?

A

Hormones released by endocrine cell which act on locally adjacent cells

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

What does autocrine mean?

A

Hormones released by a cell which act back on the same cell

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

What does intracrine mean?

A

Conversion of an inactive hormone to an active hormone that acts within the cell

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

What are the general functions of hormones?

A
  • Reproduction, growth and development: sex steroids, thyroid hormones, prolactin, growth hormones
  • Homeostasis (maintenance of internal enviroment) : Aldosterone, parathyroid hormone, vitamin D
  • Energy production, utilisation and storage: Insulin, glucagon, thyroid hormones, cortisol, growth hormones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How are hormones chemically classified?

A
  • Protein/peptide hormones (long chain amino acids)
  • Steroid hormones (derivatives of cholesterol)
  • Amino acid derivatives (one or two amino acids, mostly deriving from tyrosine and is very small)
  • Fatty acid derivatives
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Give examples of protein/peptide hormones

A
Hypothalamic hormones
Pituitary hormones
Insulin
PTH
Calcitonin

These tend to act in classical endocrine signalling

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

Give examples of steroid hormones

A
Cortisol
Aldosterone
Oestrogen
Androgens
Progestagens
Vitamin D
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Give examples of amino acid derivatives

A

Adrenaline
Noradrenaline
Thyroid hormones (all from tyrosine)
Melatonin (from tryptophan)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Give examples of fatty acid derivatives

A

Prostaglandins
Thromboxanes
Prostacyclin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What type of hormone starts out as a prohormone?

A

Protein and Peptide Hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the precursor of all steroid hormones?

A

Cholesterol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is a steroid nucleus?
It is made from the cleaving of certain groups of cholesterol which eventually forms a steroid hormone.
26
Explain how hormones have different natures of transport in the body
They will spend different lengths of time in circulation and the mode of transport will vary
27
Compare the natures of transport of protein and peptide hormone, Tyrosine dervative hormones , thyroid hormones and steroids
Protein and Peptides - Half life of minutes - Mostly circulating freely (unbound) because it is soluble and can easily be transported dissolved in water Tyrosine Derivatives - Half life of seconds Thyroid hormones - Hours - They are bound to plasma proteins in their transport in blood Cholesterol derivatives (steroids) - Hours to days - Bound to plasma proteins
28
What is neuroendocrine integration?
The nervous system and endocrine system are linked and interact
29
Describe the structure of the posterior lobe of the pituitary gland
The magnocellular neuron projects to the posterior lobe of the pituitary gland and regulates this area. It is supplied by the inferior hypophyseal artery which then becomes a capillary network and then becomes inferior hypophyseal vein.
30
What does the posterior lobe of the pituitary gland release?
Oxytocin | ADH
31
Describe the structure of the anterior lobe of the pituitary gland
The parvocellular neuron project down the the capillaries in the mediam eminence. It is supplied by the superior hypophyseal artery and its capillaries become the hypophyseal portal vein which travels to the secondary capillary network and finally becomes the hypophyseal portal vein again.
32
What does the anterior lobe of the pituitary gland release?
``` GH Prolactin TSH ACTH LH FSH ```
33
Explain the three tier system of the hypothalamus pituitary axis
Hypothalamus ----> Releasing/Inhibiting neurohormones This stimulates the Pituitary Gland --------------->stimulating trophic hormones TSH ------> Thyroid ACTH----> Adrenal Cortex LH/FSH -----> Gonads
34
Explain the role of the posterior pituitary hormones (Oxytocin and ADH)
Oxytoxin- Involved with cervix/uterus and are a type of positive feedback in uterine contractions. It is also involved with the nipples and cause milk ejection (neuroendocrine relax) ADH acts as a vasoconstrictor (V1 receptors) as well as increasing permeability of collecting ducts (V2 receptors). ADH is stimulated to be released depending on the osmoreceptor/volume receptors
35
Does the posterior pituitary gland produce hormones?
No | It secreted hormones brought down from the hypothalamus
36
Which part of the pituitary gland releases trophic hormones and what are they?
The anterior pituitary gland TSH ACTH LH/FSH
37
Explain how ACTH is released
The hypothalamus releases corticotrophin releasing hormone (CRH) This increases the release of adrenocorticotrophic hormone (ACTH) from anterior pituitary gland ACTH acts on the adrenal cortex
38
Explain how TSH is released
Hypothalamus releases thyroid releasing hormone (TRH) This stimulates the anterior pituitary gland to release thyroid stimulating hormone (TSH) TSH acts on the thyroid
39
Explain how TSH is inhibited
Growth hormone inhibiting hormone (GHIH=Somatostatin) is released from the hypothalamus This decreases the amount of TSH released from anterior pituitary
40
Explain how LH and FSH is released
Gonadotrophin releasing hormone (GnRH) is released from the hypothalamus This stimulates Luteinising hormone (LH) and Follicle stimulating hormone (FSH) FSH/FSH act on the gonads
41
Explain how prolactin (PRL) is release is inhibited
Dopamine is released from the hypothalamus This inhibits prolactin from the anterior pituitary
42
Explain how growth hormone is released and inhibited
The hypothalamus produces growth hormone releasing hormone (GHRH) or growth hormone inhibiting hormone (GHIH) This either stimulates or inhibits growth hormone (GH) from anterior pituitary
43
Explain negative feedback on the hypothalamic-pituitary axis
Hypothalamus will interact with the pituitary (by releasing neurohormones) which will act on the effector of the organ causing release of hormone This feedbacks to the hypothalamus and pituitary. If there is excess hormone, this will be detected and less stimulation occurs so less hormone is produced.
44
What keeps hormone concentration in the body constant?
There is negative/positive feedback regulation of hormones in the body, to try keep the levels constant.  
45
Explain negative feedback control of thyroid hormone synthesis and secretion
The anterior pituitary gland is stimulated by TRH from the hypothalamus. The anterior pituitary gland then secretes TSH which stimulates the thyroid gland to release T4 and T3. If there becomes too much T3 and T4 circulating, T3 and T4 will negatively feedback to the anterior pituitary and the hypothalamus which will produce less TSH and TRH respectively. Conversely if there is too little thyroid hormone, the lack of negative feedback means more TRH and TSH will be produced leading to rise on thyroid hormones.
46
What releases TSH and what does it do?
The anterior pituitary releases TSH. | TSH which stimulates the thyroid gland to release T4 and T3.
47
How is cortisol androgen production stimulated?
Hypothalamus releases CRH and VP. | This stimulates the anterior pituitary to release ACTH. The adrenal cortex then releases cortisol androgens.
48
What regulates cortisol?
Our biological clock
49
What stimulates the hypothalamus to release CRH and VP?
Circadian rhythm | Stress
50
What pattern are hormones secreted in?
Pulsatile pattern
51
Name the 4 different type of rhythms
Daily rhythms include: - Circadion (bio clock-24 hours) - Diurnal (Day/night cycle) Monthly cycles (e.g. female reproduction) Annual cycles (mostly to do with animals)
52
Compare the pulsatile rhythm of LH and Prolactin
The pulsatile rhythm of LH shows it peaking every two hours, whereas prolactin is only released during sleep.
53
Explain how distrupted sleep can affect a childs' growth
If the dinurnal pattern is broken up (distrupted sleep) there is not a big spike in growth hormone. In other words, the sleep related rise in growth hormone secretion doesn’t occur when the normal light/dark cycle is disturbed.
54
Does the pulsatile pattern of hormones stay constant?
The pulsatile pattern of LH (and other hormones such as growth hormone) can vary throughout life
55
How can disorders of the endocrine system arise?
There may be an excess or deficiency of hormones due to: - Impaired synthesis of hormones - Problems with transport and metabolism of hormones - Resistance to hormone action which can cause disorders
56
What happens if there is to little cortisol?
If your adrenal glands stop working (due to autoimmune or cancer) and you therefore produce little cortisol, then the levels of ACTH and CRH will increase, because there will not be that negative feedback. This would be detected as Addisons’s disease.
57
What happens when there is too much cortisol?
If there is too much cortisol (due to a tumour secreting cortisol or ACTH), this can be detected. If the tumour is in the anterior pituitary secreting lots of ACTH, it will mean lots of cortisol will be being produced but unable to carry out negative feedback properly as the tumour is producing lots of ACTH. This is the reason for Cushing’s disease where the patient has high levels of cortisol and ACTH.
58
What can resistance to circulating androgens result in?
Testicular feminisation
59
What can vitamin D resistance result in?
Rickets
60
What does exocrine again?
Glands that produce substances directly onto epithelial surface