The Endocrine System Flashcards Preview

A2 OCR Biology F214 > The Endocrine System > Flashcards

Flashcards in The Endocrine System Deck (21)
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1
Q

Define hormone

A

Molecules released by endocrine glands, directly into the blood

2
Q

What is the job of a hormone

A

To act as a messenger carrying a signal from the endocrine gland to a specific target organ or tissue

3
Q

Define endocrine gland

A

A gland that secretes hormones directly into the blood

4
Q

Define exocrine gland

A

A gland that secretes molecules into a duct which carries the molecules to where they need to go

5
Q

Define target cell

A

Cells with a special receptor on their plasma membrane. The receptor is complementary to a hormone molecule

6
Q

What is adenyl cyclase used for

A

The enzyme associated with the receptor for many hormone molecules e.g. adrenaline

7
Q

What are the two types of hormone

A

Steroid

Protein

8
Q

Give three properties of a steroid hormone

A

Lipid soluble
Not water soluble
Diffuse through cell membrane and combine with receptor protein in cytoplasm
Hormone-receptor complex inside plasma membrane causes cell to respond to hormone by interacting with cell DNA and stimulating protein synthesis
Sex hormones e.g testosterone

9
Q

Give three properties of a protein hormone

A

Water soluble
Not lipid soluble
Cannot pass through the plasma membrane of target cell
Made up of amino acids
Combine with receptor hormones on the cell membrane
Hormone-receptor complex on the cell membrane induces an internal response by the cell
e.g. adrenaline, insulin, glycogen

10
Q

Give four effects of adrenaline on the body

A
  • Relax smooth muscle in bronchioles
  • Increase stroke volume of the heart
  • Increase heart rate
  • Causes general vasoconstriction (VS away from non-essential organs)
  • Stimulates breakdown of glycogen to glucose
  • Dilates pupils
  • Increases mental awareness
  • Inhibits action of the gut
11
Q

Describe the effect of adrenaline on liver cells

A
  • Binds to glycoprotein receptors on the plasma membrane of target cells
  • This stimulates the enzyme adenyl cyclase
  • This produces cAMP from ATP
  • This second messenger activates a cascade of enzymes
  • The last enzyme is protein kinase A
  • This binds to glycogen phosphorylase (GP)
  • GP then converts glycogen into glucose in the liver
12
Q

Name the two regions of the adrenal gland

A

Adrenal cortex

Adrenal medulla

13
Q

What does the adrenal cortex do

A

Uses cholesterol to produce steroids

14
Q

What does the adrenal medulla do

A

Manufactures and secretes adrenaline in response to stress e.g pain

15
Q

What are the two types of steroid the adrenal cortex produces

A

Glucocorticoids

Mineralocorticoids

16
Q

What do glucocorticoids do

A

Stimulate synthesis of glycogen in the liver

17
Q

What do mineralocorticoids do

A

Control the Na+ and K+ in the blood

18
Q

What do alpha cells secrete

A

Glucagon

19
Q

What does glucagon do

A
Causes the conversion of glycogen and glucose 
Increase the rate of gluconeogenesis
Prevents Hypoglycaemia
Increases respiration of fats
Suppresses the release of insulin
20
Q

What do beta cells secrete

A

Insulin

21
Q

What does insulin do

A

Causes cells to take up glucose from the blood
-Stores it as glycogen
It causes the conversion of glucose to fat
Increases respiration of carbohydrates
Suppresses the release of glucagon