Option D.5 Hormones and metabolism (AHL) Flashcards Preview

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Flashcards in Option D.5 Hormones and metabolism (AHL) Deck (44)
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1

Where are hormones secreted from?

From Endocrine glands (ductless glands) directly into bloodstream

2

Outline journey of hormones

Secreted from endocrina glands;
in small quantity;
travels directly via bloodstream (only briefly);
to TARGET CELLS/ORGANS;
control and coordinate several body activities;
unused hormones are broken down in liver;
must be excreted continuously

3

What is the difference between hormone and nervous system?

nervous system:
- quick, precise communication
hormones:
- specific changes in metabolism and development (extended period)
BOTH coordinated by brain

4

Which human organ is the only one that has endocrine and exocrine glands?

Pancreas

5

Contrast Endocrine and exocrine glands

Endocrine glands:
- secrete hormones
- deliver directly via bloodstream
- at target organs, triggers specific metabolic reactions

Exocrine glands:
- secrete (digestive) enzymes
- deliver via ducts (lumen of a gut or body surface)

6

Give example of an endocrine gland

pituitary gland:
- secrete anti diuretic hormone; targeted at collecting ducts of kidney tubules
Gonads:
- sex hormones; targeted at gonads
Pineal gland:
- secrete melatonin; targeted at tissues/organs responding to our body clock

7

Give example of an exocrine gland

sweat gland:
- sweat on skin surface
salivary glands:
- saliva into mouth
gastric gland:
- gastric juice into stomach

8

What are the three chemical categories of hormones?

steroid derived from cholesterol;
proteins;
tyrosine derivative;

9

What is an example of a tyrosine derivative hormone?

thyroxin - four iodine atoms

10

What is an example of a peptide hormone?

insulin; FSH; LH

11

what is an example of a steroid hormone?

testosterone; progesterone

12

How do lipid soluble hormones influence metabolism?

STEROID HORMONES:
- diffuse into blood through lipid bilayer of plasma membrane;
- hormone binds to receptor (cytoplasm or in nucleus)
- receptor is activated, alters expression of genes

13

How do receptor hormones promote the transcription of specific genes

receptor hormone complex can:
cause activation of gene
- transcribes RNA
- RNA leaves nucleus
- directs formation of protein
- new protein brings functional/structural change to cell;
can turn off gene
- interrupts cell process

14

What are water soluble hormones?

PEPTIDE HORMONES:
- CANNOT pass through membrane directly
- bind to receptors in plasma membrane of target cell

15

What are second messengers?

small water soluble molecules that
- quickly spread throughout cytoplasm
- relay signals through out cells

16

What are the most common second messengers?

calcium ions and cAMP

17

What is the role of second messengers?

binding hormones causes CASCADE EFFECT:
- activation of enzymes in membrane
- ATP converted into cAMP
- cAMP activates protein kinase enzymes;
- this adds phosphate to enzymes
- can activate enzyme /or inactivate

18

What happens to cAMP after a brief period of use?

inactivated by enzyme; impact of hormone (it was helping) terminates

19

Outline role of second messenger using example of a specific hormone

- under threat, organism needs blood glucose (energy)
- epinephrine released and reaches liver
- binds to G protein couple receptor
- G protein activated
- activates adenylyl cyclase to convert ATP to cAMP
- CAMP activates protein kinase enzyme;
- activates glycogen breakdown

20

What is hypothalamus?

part of brain has major endocrine functions;
well supplied with blood vessels;
site of special neurons

21

What are the key roles of hypothalamus?

monitoring blood composition;
maintenance of internal environment - homeostasis

22

What does the pituitary gland consist of?

anterior pituitary and posterior pituitary

23

How does the hypothalamus control endocrine activity of pituitary glands?

hypothalamus releases hormones from neurosecretory cells; into portal vein;
nerve impulses via neurons connected

24

What is a neurosecretory cell?

type of neuron that secretes chemical messengers which travel around body via blood

25

What do hormones secreted by pituitary glands control?

growth, development changes in body tissue/organ, reproduction and homoeostasis

26

What does anterior pituitary do?

synthesizes and secrete hormones to control growth reproduction and homoeostasis

27

Example of anterior pituitary hormone

FSH and LH

28

What do posterior pituitary glands do?

secrete oxytocin and ADH, bu are NOT produced there

29

Where are hormones released by posterior pituitary gland synthesized?

neurosecretory cells; stored in ends of axons; secretion stimulated by hypothalamus

30

What is the production/secretion of milk called?

lactation released by mammary glands after birth