Endocrinology and cell signalling Flashcards Preview

Block 1 > Endocrinology and cell signalling > Flashcards

Flashcards in Endocrinology and cell signalling Deck (62)
Loading flashcards...
0

What disease will someone with Hypoadrenalism suffer from?

Addisons

1

What is Cushsings syndrome?

Excess glucocorticoids - cortisol

2

Name 4 hormones which are synthesised in the Anterior Pituitary gland

Growth hormone
Follicle stimulating hormone
Leutinising hormone
Thyroid stimulating hormone
Adrenocorticotrophic hormone
Prolactin

3

Give 5 functions of cortisol

Maintain muscle function
Decrease bone function
Decrease connective tissue
Inhibit inflammatory and immune response
Maintain cardiac output
Facilitate maturation of foetus
Increase glomerular filtration
Modulate emotional tone

4

List 3 things which could cause excess hormone production

Neoplasm in endocrine gland
Ectopic production
Hyperplasia of endocrine tissue

5

List 4 things which could cause a deficit in hormone production

Trauma
Disease
Autoimmune attack of gland
Under development of gland

6

Give 2 examples of peptide hormones

Parathyroid
ACTH

7

How are steroid hormones synthesised?

Hydrolysis of esters or uptake of cholesterol
Cholesterol converted to pregnenalone by C P450 in mitochondria
Pregnenalone is processed in smooth ER
Then diffuses out of the cell

8

Which cells generally have autocrine signalling as a common feature?

Tumour cells
Production of growth hormones perpetuates proliferation

9

What 3 effector mechanisms can be used to change cell behaviour?

Alter gene transcription
Alter ion balance across membrane
Alter level of enzyme activity

10

Which residues does phosphorylation mostly occur on?

Serine and threonine

11

Describe the phototransduction pathway?

Photon binds to rhodopsin receptor
Transducin mediator
cGMP phosphodiesterase converts cGMP to GMP
Closes Na channels and changes membrane potential

12

In order for a molecule to diffuse across a membrane, what must occur?

Solute must dissolve in the hyrophobic core of the membrane

13

What are GLUT transporters?

Passive transporter
Glucose transported into cell and then converted to glucose 6 phosphate in order to maintain concentration gradient

14

What is an endocrine gland?

Gland which secretes hormones directly into the blood stream

15

What is an exocrine gland?

Gland which secretes chemicals via a duct

16

What tissues have endocrine function?

Heart
Gut
Adipocytes
Placenta

17

What are 3 types of hormones?

Polypeptides
Steroids
Modified amino acids

18

Describe steroid hormone synthesis

Hydrolysis of esters and cholesterol uptake
Conversion of cholesterol to pregnenalone in mitochondria
Processing of pregnenalone in smooth ER
Diffusion from the cell

19

Describe protein and peptide hormone synthesis

Gene transcription
Translation on rough ER
Post translational modification in Golgi
Packaging into secretory vesicles which are stored and ready for release when signalled

20

How is parathyroid hormone synthesised?

Peptide hormone
Pre-pro-PTH with signal, pro, biologically active and c terminal fragments
Cleaved twice to form active PTH

21

How is ACTH formed?

Peptide hormone
Formed as propriomelanocortin which is cleaved into ACTH, amino terminal fragment and B-lipotropin

22

Give an example of a tyrosine kinase receptor system

Insulin

23

What is the only example of a positive feedback loop in endocrinology?

LH surge in menstruation caused by oestrogen levels

24

Describe the anatomy of the thyroid gland

2 lateral lobes and an isthmus
In front of trachea
Large: 5cm long, 2-3cm deep, 3-4cm wide, 15-20g

25

What hormones does the thyroid gland make?

Basal metabolic rate: thyroxine (T4), tri-iodothyronine (T3)
Calcium homeostasis: calcitonin

26

What are T3 and T4 derived from?

Tyrosine
4 iodine molecules in T4
3 iodine molecules in T3

27

Describe the thyroid gland microstructure

Made of follicles: follicular cells containing colloid, parafollicular cells (c cells)
Follicular cells produce T3 and T4
Parafollicular cells produce calcitonin

28

What are the steps of thyroid hormone synthesis?

Thyroglobulin synthesis (from tyrosine) - colloid
Uptake and concentration of iodide (I-)
Oxidation of iodide to iodine (Thyroid peroxidase, luminal membrane of follicular cell)
Iodination of thyroglobulin to MIT and DIT mono-, di-iodotyrosine
Conjugation of 2 iodinated tyrosine molecules to form T4 or T3
Secretion

29

What does the thyroid gland do to iodide?

Concentrates it
Follicles actively accumulate iodine (iodide) from blood and secrete it into colloid