Brainscape's Knowledge GenomeTM

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


See full index

Endocrinology > The Endocrine Pancreas > Flashcards

The Endocrine Pancreas Flashcards

1
Q

Anatomy of the pancreas

A

Pancreas nestles with stomach and the duodenum. Overlays aorta and vein. Has a head, body and tail.

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

pancreas develops embryologically as an outgrowth of the

A

foregut

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

exocrine function

A
  • Digestive enzymes directly into the duodenum (99% exocrine tissue) o Alkaline secretions via the pancreatic duct to duodenum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

endocrine function

A
  • Hormone production and release (1% of endocrine tissue) - From islets of Langerhans
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

is the pancreas mainly exocrine or endocrine

A

99% exocrine

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

important polypeptide hormones secreted by the pancreas

A
  • Insulin - Glucagon - Somatostatin - Pancreatic polypeptide - Ghrelin - Gastrin - Vasoactive intestinal peptide (VIP)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

major cell types in islets

A
  • Beta cells- insulin
  • Alpha- glucagon
  • Delta- somatostain
  • PP cells- OO
  • Epsilon cells- Ghrelin
  • G cells – Gastrin
  • VIP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

which hormones regulate the metabolism of CHOs, proteins and fats

A

insulin (CHOs, proteins and lipids) and glucagon (CHO and lipids)

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

properties of insulin and glucagon

A

Water soluble hormone

o Carried dissolved in plasma- no special transport

o Short half life- 5 mins

o Interacts with cell surface receptors on target cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

insulin main action

A

lowers blood glucose and promotes energy storage

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

target tissue of insulin

A

liver, adipose and skeletal muscle

  • increases uptake of glucose via insertion of GLUT4 channels
  • also increases glycogen synthesis in the liver
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

is insulin anabolic or catabolic

A

anabolic

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

main action of glucagon

A

opposed insulin- raises blood glucose

  • stimulates glycogenolysis
  • stimulates glucosneogensis
  • stimulates lipolysis

stimulates proteolysis

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

target tissue of glucagon

A

liver and adipose

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

is glucagon anabolic or catabolic

A

catabolic

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

when blood glucose of high after a meal

A
  1. high blood glcuose promotes release of insulin from Beta cells of the pancreas
  2. insulin stimulates glucose uptake from blood increasing uptake in muscle and fat
  3. insulin also stimulates the conversion of glucose to glycogen in the liver lowering blood glucose
18
Q

when blood glucose of low during fasting

A
  1. blood glucose low stimulates the release of glucagon
  2. glucagon stimulates the breakdown of glycogen to glucose
  3. glucoseneogensis stimulates
  4. glycogensis inhibited
19
Q

importance of plasma glucose

A

Brain uses glucose at fastest rate in body

  • Sensitive to falls in glucose and rise (increase osmolarity- shrinking)
  • Circulation glucose needs to be controlled
20
Q

normal blood glucose

A

3.3-6 mmol/L

(after meal 7-8 mmol/L)

21
Q

renal threshold (point at which the tissue in the kidneys cannot deal with the amount of glucose in the plasma (cant filter and reabsorb), so instead of absorbing all glucose, glucose will be excreted in the urine (glycosuria))

A

10mmol/L

22
Q

in pregnant women and the elderly the renal threshold

A

increases

23
Q

Insulins effect on CHO, lipid and protein metabolism

A

Carbohydrate metabolism

  • Increase glucose transport across the cell membrane
  • Increases glycolysis
  • Stimulate glycogenesis
  • Inhibits glycogenolysis breakdown
  • Inhibits gluconeogenesis

Lipid metabolism- decrease lipolysis

Protein metabolism – decrease proteolysis

24
Q

structure of insulin

A

big peptide with an alpha helix structure

51 aa

2 polypeptide chains

2 disulphide bridged= rigid structure

25
Q

Insulin synthesis

A
  1. The single polypeptide preproinsulin is synthesised in the nucleus of β cells.
  2. A signal peptide on the preproinsulin directs the polypeptide chain to the rough endoplasmic reticulum.
  3. Preproinsulin is cleaved to proinsulin.
  4. The proinsulin is folded and the disulphide bridges are formed.
  5. Proinsulin is transported to the golgi apparatus where it is cleaved to produce insulin and C-peptide, which are both packaged into a secretory granule that then waits for a signal to be released.
26
Q

C-protein

A

can be used to measure insulin

27
Q

Insulin is then released from the pancreatic β-cells via the following pathway

A
  1. Food intake results in an increase in blood glucoseconcentration.
  2. Glucose diffuses into the pancreatic β cell via GLUT2transporters.
  3. The increase in intracellular glucose causes an increase in glycolysis and ATP production.
  4. The increase in ATP production increases the intracellular ATP:ADP ratio.
  5. The increased ATP:ADP ratio causes the ATP-dependant K+channels on the cell membrane to close.
  6. The closure of the K+ channels causes the membrane to depolarise.
  7. Voltage-gated Ca2+ channels on the cell membrane open, and there is a calcium influx into the cell.
  8. The increase in intracellular calcium causes secretory granules (insulin) to be released via exocytosis.
28
Q

release of insulin increases the uptake of glucose into cells of target tissue (liver, adipose, skeletal muscle) via the

A

insertion of GLUT4 channels and increase in glycogen synthesis

29
Q

GLUT 4

A

allows transport of glucose across the target cell membrane

30
Q

insulin receptors

A

are dimers with two identical subunits, made of one α and one β chain connected by a disulphide bond.

The α chain is on the exterior of the cell membrane, and the β chain spans the membrane in a single segment.

31
Q

overall insulin…

A

Increases number of GLUT4 receptors on adipose, skeletal muscle and liver increasing uptake of glucose

32
Q

GLUT 2

A

acts as a glucose sensor on pancreatic cells

33
Q

glucagon is the hormone that

A

opposes insulin- acting to raise glucose levels

34
Q

main actions of glucagon

A

stimulates glycogenolysis (liver)

stimulates glucoseneogenesis

stimulates lipolysis and proteolysis

35
Q

structure of glucagon

A

29 amino acid structure comprised of only a single polypeptide, meaning its synthesis is more simple than insulin’s

36
Q

synthesis of glucagon

A

Synthesised in RER of alpha cells, packaged in golgli, marginalised at cell surface and wait for signal to exocytose (in response to low glucose levels)

37
Q

when glucose is low

A
  • Granules move to the cell surface
    • Margination- movement of storage vesicle to cell surface
    • Exocytosis- fusion of vesicle membrane with plasma membrane with the release of the vesicle content
38
Q

clinically when is glucagon used

A

Glucagon in emergency medicine is used when a person with diabetes is experiencing hypoglycaemia and cannot take sugar orally

39
Q

where is glucagon most active

A

int he liver

40
Q
A

Endocrinology (12 decks)

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