Brainscape's Knowledge GenomeTM

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


See full index

My Endocrinology > Basic Science > Flashcards

Basic Science Flashcards

1
Q

What cells secrete insulin and glucagon?

A
  • insulin: Beta cells

- glucagon: Alpha cells

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

What so delta and PP cells secrete?

A
  • delta cells: somatostatin

- PP cells: pancreatic polypeptide

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

What is the simple pathway for the production of insulin?

A
  • made in the RER of pancreatic beta cells as preproinsulin
  • this is cleaved to make insulin
  • C peptide is made in a 1:1 ratio (no known function)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the short-acting form of insulin?

A

lispro= most rapid acting and is used in combination with longer acting types

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

What is the long-acting form of insulin?

A

glargine= released slowly into the blood and the level is maintained during sleep

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

What is the process of secretion of insulin?

A
  • glucose enters beta cells through GLUT2
  • glucose is phosphorylated by glucokinase
  • increase in glucose metabolism so increase in intracellular ATP from respiration
  • ATP inhibits ATP-sensitive K+ channels
  • this causes depolarisation
  • voltage-gated Ca2+ channels open
  • an increase in Ca2+ causes insulin to be released
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the features of glucokinase?

A
  • Km is at ideal glucose concentration

- action increased as glucose increases

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

What is the fasting glucose in diabetics?

A

above 7

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

What is the pattern of release of insulin from a beta cell?

A

it is biphasic with a reserve pool and a readily releasable pool (RRP)

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

What is the structure of a Katp channel?

A
  • 4x Kir6
  • 4x SUR1
    this forms an octomeric structure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the factors that can cause change in Katp?

A
  • normally, ATP inhibits Katp to cause depolarisation
  • Katp can be inhibited by sulphonylurea
  • Katp can be stimulated by diazoxide
    (overwork Beta cells)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What mutation can lead to neonatal diabetes?

A

Kir6.2 which is part of the Katp channel as there will be more Katp channels and they will be overactive

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

What is MODY?

A

Maturity-onset diabetes of the young

  • familial disease with beta cell genetic defect
  • associated with transcription factors
  • MODY2 involves glucokinase impairment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the definitions of the types of diabetes?

A
  • Type 1= loss of insulin secreting beta cells
  • MODY= defective glucose sensing and/or loss of insulin secretion
  • Type 2= hyperglycaemia with hyperinsulinaemia so there is decreased insulin sensitivity in tissues
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the processes that insulin promotes?

A

this is an anabolic hormone

  • amino acid uptake in the muscle
  • DNA synthesis
  • protein synthesis
  • growth repossess
  • glucose uptake in muscles and adipose tissue
  • lipogenesis in adipose tissue and liver
  • glycogen synthesis in liver and muscle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the processes that insulin inhibits?

A
  • gluconeogenesis in the liver

- lipolysis in the adipose tissues

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

What is the outline of insulin sensing?

A
  • insulin receptors = receptor tyrosine kinase

- signalling pathways = PI3K and RAS which are regulated by growth factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the features of Leprechaunism?

A
  • association with dwarfism
  • defects in insulin binding or insulin receptor signalling
  • growth problems
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the main features of DKA?

A
  • increased HR
  • vomiting
  • dehydration
  • smell of ketones on breath
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Where are ketone bodies made?

A

liver mitochondria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How are ketone bodies made?

A

when the ration of carbohydrates:fatty acids is changed when there is an increase in FAs the more ketone bodies are made from acetyl-coA

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

What are ligand-gated ion channels?

A
  • in neurones and muscle cells
  • bound and activated by hormones and neurotransmitters
  • these cause a response in milliseconds
23
Q

What happens to open ligand-gated ion channels?

A

there is a chemical change when the hormone binds so there is structural change

24
Q

What disease occurs when ligand-gated ion channels are distrupted?

A

Myasthenia Gravis- autoimmune condition with loss of ACh receptors

25
Q

What is the process of reaction in a GPCR?

A
  • hormone binds to eg B2 causing a conformational change
  • G proteins attach
  • alpha is coupled to GDP so when it binds, GDP is made into GTP
  • Alpha activates adenylyl cyclase
  • ATP –> cAMP –> PKA
  • PKA inhibits MLCK activity
  • GTP hydrolysis stops the process
26
Q

What actions can adrenaline have at different cells?

A
  • at beta2 = bronchodilator by activation
  • at alpha2 = relaxes GI tract by inhibition
  • at alpha1 = vasoconstrictor by activation
27
Q

What does adrenaline do to cause relaxation of the GI tract?

A
  • adenylyl cyclase is already working in alpha2
  • Galpha causes this to switch off
  • betax causes activation of K+ channels so there is inhibition
  • this causes relaxation of the GI tract
28
Q

How does adrenaline cause vasoconstriction?

A
  • when bound to alpha1 it activates phospholipase C so PIP –> DAG IP3
  • this increases the amount of Ca2+ ions so there is vasoconstriction
29
Q

What are the features of receptor tyrosine kinases?

A
  • there a many cellular responses

- these occur in hours

30
Q

What is the process of activation of receptor tyrosine kinases?

A
  • insulin binding causes conformational change
  • this unites parts of the receptor
  • autophosphorylation
  • tyrosine is phosphorylated by ATP molecules
  • relay proteins attach and activate other proteins
31
Q

What does autocrine mean?

A

chemicals released from cells bind to receptors on or in the cell releasing them which is usually negative feedback

32
Q

What does paracrine mean?

A

chemicals released from cells bind to receptors on adjacent cells

33
Q

What does endocrine mean?

A

chemicals released from secretory cells transported via circulatory system and target cells that are some distance away

34
Q

What are the different intrinsic and extrinsic responses?

A
  • intrinsic= paracrine and autocrine

- extrinsic= nervous system and endocrine

35
Q

What are the main endocrine glands?

A
  • pituitary and hypothalamus
  • parathyroid
  • adrenals
  • pancreas
  • ovaries
  • testes
  • thyroid
36
Q

What are the subtypes of hormones?

A
  • steroids : derived from cholesterol
  • proteins and peptides : amino acid chains
  • tyrosine and tryptophan derivatives : amino acid based
37
Q

What do different levels of TSH mean?

A
  • suppressed : hyperthyroid
  • normal : normal thyroid
  • raised : hypothyroid
38
Q

What are the major glands of the body?

A
  • thymus
  • adrenals
  • pancreas
  • testes
  • hypothalamus
  • pineal
  • pituitary
  • ovary
  • thyroid
  • parathyroid
39
Q

What is a hormone?

A

a substance elaborated by one cell to regulate another cell

40
Q

What does the hypothalamus do?

A
  • is controlled by the nervous system
  • regulates secretion of regulatory hormones
  • synthesises hormones and transports them
  • controls secretion of adrenaline and noradrenaline to regulate sympathetic control
41
Q

What are levels of hormone determined by?

A
  • diurnal control dependent on external cues such as light and dark
  • dependent on rate of elimination from the body
42
Q

What is an example of hormones that have complementary actions?

A

glucagon and cortisol

43
Q

What are the features of steroid hormones?

A
  • hydrophobic and lipophilic
  • synthesis rate controls the amount (depends on diurnal expression of enzymes of production)
  • not stored, only secreted
  • can pass through bilayer
  • bind to steroid receptor in cytoplasm which transports it to nucleus
44
Q

What are the features of amine-derived hormones?

A
  • hydrophilic so need receptor to get in
  • catecholamines can move inside unbound
  • thyroid amine hormones are bound to carrier proteins
  • tyrosine is precursor for catecholamines
  • stored until needed
45
Q

What are the features of peptide and protein hormones?

A
  • usually have a tertiary structure
  • hydrophilic so are unbound in plasma
  • synthesised as precursors and stored
46
Q

Which hormones need carrier proteins?

A

steroid and thyroid

47
Q

What does binding to carrier proteins do to the hormones?

A
  • facilitates hormone transport
  • increases half-life
  • provides reservoir for hormone
48
Q

What do monogenic and polygenic mean?

A
  • monogenic is one causative gene

- polygenic is multiple causative genes

49
Q

How are mitochondrial defects passed?

A

through the paternal line

50
Q

What are the features of Von Hippel Lindau?

A

this is an autosomal dominant condition which causes vascular tumours

51
Q

What are the features of Neurofibromatosis Type 1?

A
  • axillary freckling
  • cafe-au-lait patches
  • neurofibromas
  • this is a common condition
52
Q

What does plasma osmolality equal?

A

2(Na+ + K+) + urea + glucose

53
Q

What process generates ketone bodies?

A

lipolysis leads to ketoacidosis

54
Q

What molecule binds the majority (70%) of thyroid hormone?

A

thyroxine binding globulin

My Endocrinology (12 decks)

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