Brainscape's Knowledge GenomeTM

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


See full index

OCR A BIOLOGY > 5.4 Hormonal Communication > Flashcards

5.4 Hormonal Communication Flashcards

1
Q

What is an endocrine gland?

A

A ductless gland that secretes it’s product directly into the blood or lymph

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

What is an exocrine gland?

A

A gland that secretes it’s product into a duct which takes the secretions to the site of action

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

What are the 2 types of hormone?

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

What are the features of protein hormones?

A
  • insoluble so can’t diffuse through plasma membrane
  • requires receptors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are the features of steroid hormones?

A
  • soluble so can pass through plasma membrane
  • bind to receptors on cytoplasm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are examples of steroid hormones?

A
  • testosterone
  • progesterone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are examples of protein hormones?

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

where are the adrenal glands found?

A

above the kidneys

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

what are the 2 parts of the adrenal gland?

A
  • adrenal cortex
  • adrenal medulla
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what does the adrenal cortex produce?

A

steroid hormones using cholesterol:
- glucocorticoids
- mineralocorticoids

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

what is an example of a glucocorticoid?

A
  • cortisol
    It stimulates the synthesis of glycogen in the liver and is released in response to stress
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is an example of a mineralocorticoid?

A
  • aldosterone
    It is release to increase the uptake of Na+ and K+ into the blood from the DCT
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what does the adrenal medulla produce?

A
  • protein hormones
    e.g. adrenaline
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

how do protein hormones work?

A
  1. protein bins to receptor on plasma membrane, which activates a G protein.
  2. G protein activates an effector molecule which produces an enzyme to convert ATP to cAMP
  3. cAMP is the secondary messenger which activates an enzyme cascade or acts directly on other proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how do steroid hormones work?

A
  1. steroid hormone passes through plasma membrane and binds to receptor in cytoplasm or nucleus
  2. the receptor steroid hormone complex acts as a transcription factor resulting in the formation of mRNA by transcription
  3. a new protein is formed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are some effects of adrenaline?

A
  • vasoconstriction
  • increased mental awareness
  • pupils dilate
  • cardiac output increases
  • piloerection
  • digestive system slows
  • bronchodilation
  • glycogen converted to glucose
17
Q

why is the pancreas an exocrine and endocrine gland?

A
  • acini secrete digestive enzymes into the pancreatic duct
  • islets of Langerhans secrete hormones into blood
18
Q

what are the islets of Langerhans?

A
  • endocrine tissue that makes up 15% of the pancreas
19
Q

what are the cells that make up the islets of Langerhans?

A
  • alpha cells (20%)
  • beta cells (70%)
20
Q

what do alpha cells do?

A

Detect blood glucose concentration and secrete glucagon to convert glycogen into glucose

21
Q

what do beta cells do?

A

Detect blood glucose concentration and secrete insulin to convert glucose into glycogen

22
Q

How do beta cells detect blood glucose concentration and respond?

A
  1. K+ channels are normally open so K+ flows out of the cell
  2. when blood glucose conc. is too high glucose diffuses into the cell
  3. glucose is metabolised to produce ATP
  4. ATP causes the K+ channels to close
  5. K+ cant leave the cell so membrane becomes positive
  6. voltage gated Ca2+ channels open
  7. Ca2+ causes vesicles to fuse with membrane so insulin is released by exocytosis
23
Q

What is exact glucose level normally needed in the blood?

A
  • 90mg in 100cm^3
  • 4-6 mmol/dm^3
24
Q

what is hypoglycemia?

A

when blood glucose levels are too low

25
Q

what is hyperglycemia?

A

when blood glucose levels are too high

26
Q

what is glycogenesis?

A

making glycogen from glucose

27
Q

what is glycogenolysis?

A

breaking down glycogen into glucose

28
Q

what is gluconeogenesis?

A

converting amino acids and glycerol into glucose

29
Q

why is it bad for blood glucose levels to be too high?

A

It damages smaller blood vessels leading to blindness, kidney failure, and amputation of extremities.

30
Q

why is insulin released?

A

to lower blood glucose levels

31
Q

why is glucagon released?

A

to raise blood glucose levels

32
Q

Outline insulins mode of action.

A
  1. insulin molecule binds to specific receptor on the liver cell surface membrane, triggering a chemical signal.
  2. vesicles containing glucose transporter proteins to fuse with the membrane
  3. glucose moves into the cell by facilitated diffusion
33
Q

where do insulin and glucagon affect?

A

target cells in the liver

34
Q

what can enzymes use excess glucose for?

A
  • respiration
  • converting to fats
  • converting to glycogen
35
Q

Outline glucagons mode of action?

A
  1. glucagon binds to receptors on liver cell surface membrane
  2. G protein is activated causing adenyl cyclase to convert ATP into cAMP
  3. cAMP activates an enzyme cascade

OCR A BIOLOGY (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions