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Biology: Module 5 > 5.4: Hormonal communication > Flashcards

5.4: Hormonal communication Flashcards

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1
Q

What is the endocrine system?

A

Uses the blood circularitory system to transport hormones

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2
Q

What are the two types of hormones?

A

Protein and Peptide
Steroid

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3
Q

What are protein and peptide hormones?

A

Not soluble in membrane so they need to bind to the cell surface membrane and release a second messenger inside the cell

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4
Q

What are steriod hormones?

A

Can pass through the membrane and enter the cell and the nuclear

  • Direct effect on the DNA in the nucleus
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5
Q

What are first messengers?

A

Non steriod hormones, signalling molecules outside the cell that bind to the cell surface membrane and initiate an effect inside th cell

  • It causes the release of the secondary messenger
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6
Q

What are secondary messengers?

A

Stimulates a change in the activity of the cell

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7
Q

How do non steriod hormones work?

4 steps

A
  1. Hormone binds to the receptor and activates the G protein
  2. The G protein acitivates an effector molecule, which converts an inactive molecule into the active secondary messenger, called adenyl cyclase
  3. Adenyl cyclase converts ATP to cyclic AMP - secondary messenger
  4. The secondary messenger may act directly on another protien or it may initiate a cascade of enzyme - controlled reactions that alter the activity of the cell
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8
Q

What is the adrenal gland divided into?

A

Outer adrenal cortex
Inner adrenal medulla

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9
Q

What makes up the adrenal cortex?

A
  • Zona glomerula
  • Zona fasisculata
  • Zona reticularis
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10
Q

What is the zona glomerulosa?

A

The outermost layer which secreates mineralocortioids such as aldosterone

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11
Q

What is the zona fasisculata?

A

The middle layer which secretes glcocorticoids such as cortisol

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12
Q

What is the zona reticularis?

A

The innermost lsyer which secretes precursor molecules that are used to make sex hormones

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13
Q

What is the adrenal medulla?

A

Found in the centre and secretes adrenaline and noradrenaline

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14
Q

Why can hormones secreted by the adrenal cortex d o and why?

A

Produces hormones that are steriod based amd enter cells directly by dissolving into the cell surface membrane and enter the nucleus and have a direct effect on DNA to cause protein synthesis

This is because it uses cholesterol

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15
Q

What is the action of the adrenal gland?

4 steps

A
  1. The steroid hormone passes through the cell membrane to a target cell
  2. The steroid horone binds with the specific receptor on the cytoplasm
  3. The receptor-steroid hormone complex enters the nucleus of the target cells and binds with the specific receptor on the chroomosomal nucleus
  4. Binding stimulates the production of the messenger RNA molecules which code for the production of the protein
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16
Q

What are the effects of adrenaline?

A
  • Relaxing smooth muscle in the bronchioles
  • Increasing stroke volume of the heart
  • Increasing heart rate
  • Dilating pupils
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17
Q

What are sections of the pancreas?

A
  • Pancreatic juices containing enzymes which are secreted into the small intestine
  • Hormones which are secreted from the islets of Langerhans into the blood
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18
Q

What are exocrine glands?

A

Secrete substances into a duct
Synthesise and release digestive enzymes

19
Q

What is a acinus?

A

Each group of exocrine cells
Secrete the enzymes they synthesise

20
Q

What are intralobular vessels?

A

Tubules from the acinus join the form them which then form the pancreatic duct

21
Q

What does the pancreatic duct do?

A

Sends fluid to first part of the small intestine (duodenum)

22
Q

What does the pancreatic fluid contain?

A
  • Pancreatic amylase - a carbohydrate which digests amylase to maltose
  • Typsinogen - inactive protease which will be converted to the active form of typsin when it enters the duodenum
  • Lipase - digests lipid molecules
23
Q

What do alpha and beta cell do?

A

Alpha - secrete glucagon
Beta - secrete insulin

24
Q

How is insulin released?

7 steps

A
  1. Potassium ion channels are open - K+ flow through
  2. Blood glucose concentration is high - the glucose moves into the cellss
  3. Glucose is metabolised to produce ATP
  4. ATP closes the potassium ion channels
  5. Amount of K+ depolarises the inside of the cell
  6. Depolarisation opens the Ca2+ ion channels
  7. Ca2+ causes vesicles of insulin to fuse with the cell membrane. Releasing insulin by exocytosis
25
Q

What is normal blood glucose concentration?

A

4 and 6mmol dm-3

26
Q

What is hypoglycaemia?

A

Blood glucose concentration is allowed to drop below 4mmol dm-3 and remian low for long periods

27
Q

What are mild and severe symptoms of hypoglycaemia?

A

Mild: Tiredness, irratibility
Severe: Seziures and death

28
Q

What is hyperglycaemia?

A

Blood glucose concentration is allowed to rise too high for long periods

  • Can lead to significant organ damage
  • Consistently higher than 7mmol dm-3 = diabetes
29
Q

What do cells in the islets of langerhans do?

A

Moniter the blood glucose concentration

  • If concentration rises or falls - alpha and beta cells detect and respond to chnage
  • High glucose - converted to glycogen
30
Q

What happens if blood glucose is too high?

4 steps

A
  1. Detected by beta cells
  2. Secrete insulin into the blood
  3. Insulin travels throughout the body in circulatory system
  4. Target cells are the liver cells and muscle cells
31
Q

How does insulin work to regulate blood glucose?

A
  1. Bind to specific receptors on target cells
  2. Activates enzyme tyrosine kinase
  3. Causes phosphorylation of inactive enzymes in the cell
  4. Activate enzymes - cascade of ensyme-controlled reactions in the cell
32
Q

What is glycogensis?

A

Glucose is converted to glycogen for storage

33
Q

What happens if blood glucose is too low?

5 steps

A
  1. Detected by alpha cells which secrete glucagon into the blood
  2. Glucagon binds to receptors on hepatocytes
  3. Stimulates a G protein
  4. Activates adenyl cyclase
  5. Activates ATP to cAMP - activates a series of enzyme controlled reactions
34
Q

What is glycogenolysis?

A

Glucogan is converted to glucose

35
Q

What is gluconeogenisis?

A

Amino acids and fats are converted into additional glucose

36
Q

What is diabetes mellitus?

A

Body is no longer able to produce sufficient insulin

  • Can lead to prolonged very high glucose concentration
37
Q

What is type one diabetes?

A

Result of an autoimmune response in which the body’s immune system attaches and destroys the beta cells

38
Q

What happens in type 1 diabetes?

4 things

A
  • No longer able to synthesise a suffcient amount of insulin
  • Cannot store excess as glycogen
  • Excess glucose in blood is not removed quickly - prolonged high concentration
  • No store of glycogen - cannot release glucose when concentration falls (hypoglycaemia)
39
Q

How is type 1 diabetes treated?

A

Using insulin injections, the glucose concentration must be monitored and correct doce of insulin administered

Alternatives:

  • Insulin pump therapy
  • Islet cell transplantation
  • A complete pancreas transplant
40
Q

What is type 2 diabetes and why does it happen?

A

Can produce insulin but not enough
As people age their specific receptors on the surface of muclse and liver cells lose their ability to respond to insulin in the blood

41
Q

What are risk factors of type 2 diabetes?

A
  • Obesity
  • Lack of regular excersize
  • A diet high in sugar
  • Being born asian or afro carribean orgin
  • Family history
42
Q

How is type 2 diabetes treated?

A

Changes in lifestyle:

  • Lose weight
  • Exerscise regularly
  • Carefully monitor diet

Medication that reduces the amount of glucose the liver releases to the bloodstream or boosts the amount of insulin released from the pancreas

43
Q

What are three advantages of using insulin from genetically modified bacteria

A
  • Exact copy of human insulin - faster acting and more effective
  • Less chance of developing tolerance to the insulin
  • Less chance of rejection due to an immune response

Biology: Module 5 (7 decks)

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