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OCR BIOLOGY (MODULE 5) > HORMONAL COMMUNICATION > Flashcards

HORMONAL COMMUNICATION Flashcards

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1
Q

What is a hormone

A

Chemical messenger:

  • secreted from endocrine gland directly into bloodstream
  • occurs due to changes in concentration of a substance
  • travel in blood plasma, carry signal from endocrine gland to specific target
  • bind to specific target cells
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2
Q

What are endocrine glands

A

Group of cells, secrete hormones directly into blood capillaries (no ducts)
E.g. pancreas, adrenal glands

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3
Q

What are exocrine glands

A 
Secretes molecules (not hormones) into ducts 
E.g. saliva, bile, digestive, enzymes
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4
Q

What are examples of non-steroid hormones

A

POLAR
E.g. adrenaline, insulin, ADH
First messengers

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5
Q

Explain what is meant by first messenger

A

Non-Steroid hormones
Bind to receptor on cell surface membrane, releases second messenger inside the cell
Often act via G protein in the membrane

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6
Q

Explain what is meant by a second messenger

A

Stimulate a change in the activity of the cell
In many cases, enzyme adenylyl cyclase is an effector molecule that converts ATP into cyclic AMP
May activate enzyme controlled reactions

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7
Q

Examples of steroid hormones

A

NON POLAR

E.g. oestrogen, testosterone

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8
Q

What are steroid hormones

A

Hydrophobic- can dissolve in hydrophobic region of phospholipid (simple diffusion)

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9
Q

Explain a steroid hormone

A

Passes directly through cell surface membrane and binds with specific receptor in the cytoplasm
This complex enters nucleus of the cell and acts as transcription factor on DNA
Either promotes or inhibits transcription of gene

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10
Q

Where are the adrenal glands located

A

Just above kidneys

Divided into outer adrenal cortex and inner adrenal medulla

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11
Q

How many layers are in the adrenal cortex

A

3

All secreting steroid hormones

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12
Q

What hormone does the first layer of the adrenal cortex secrete and what is its function

A

Mineralocorticoids
E.g. aldosterone
Controls levels of Na+ and K+ in the blood
Increases absorption of Na+ and decrease for K+
Maintains blood pressure

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13
Q

What hormone does the second layer of the adrenal cortex secrete and what is its function

A

Glucocoticoids
E.g. cortisol
Released in response to stress or low blood glucose levels
Regulates immune response

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14
Q

What hormone does the third layer of the adrenal cortex secrete and what is its function

A

Androgens

E.g. precursors for sex hormones

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15
Q

What does the adrenal medulla secrete

A

Non steroid hormones

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16
Q

What hormones are secreted by the adrenal medulla

A

Adrenaline and noradrenaline (fight or flight)

17
Q

Function of adrenaline

A

Increases heart rate, increase blood glucose (glycogen broken dow. in liver)

18
Q

Function of noradrenaline

A

Works with adrenaline in response to stress, producing effects of an increased heart rate, increases blood pressure

19
Q

When are hormones in the medulla secreted

A

When the sympathetic nervous system is stimulated

In response to stress

20
Q

What is the exocrine function of the pancreas

A

Location- acinus (cells found in groups surrounding. tubules)
Details- pancreatic juice released from cells and secreted into tubules at centre of group. Join to form interlobular ducts which join to from pancreatic ducts, joins to duodenum

21
Q

Endocrine function of the pancreas

A

Location- Islets of Langerhan- group of cells in pancreas
Details- alpha cells produce glucagon, beta cells produce insulin
Hormones secreted directly into blood stream

22
Q

What is diabetes

A

Where someone is unable to metabolise carbohydrates properly, particularly glucose

23
Q

Symptoms of diabetes

A

Extreme fatigue
Blurry vision
Weight loss

24
Q

Explain hypoglycaemia

A

Mild- tiredness and irritability
Severe- impairment of brain function and confusion, could lead to seizures, unconsciousness
Decreased blood glucose concentration

25
Q

Details of type 1 diabetes

A

Unable to produce insulin (B-cells on isle of Langerhan dent produce insulin)
Cannot be prevented or cures, treatment available
Can arise as result of an autoimmune disease

26
Q

Details of type 2 diabetes

A

Cannot effectively use insulin and control blood sugar levels
Either because:
1. B-cells don’t produce enough insulin
2. Cells don’t respond properly to insulin
Therefore cells lose responsiveness to insulin so cannot take up enough glucose, leaving it in bloodstream
Result of obesity and decreased physical activity

27
Q

Treatment for type 1

A

Regular injections of insulin
Regularly test blood glucose levels
Increased insulin= increased glucose absorbed by cells

28
Q

Treatment for type 2

A

Match carbohydrate level to exercise level
Over weight people encouraged to lose weight
Drugs- stimulate insulin production

29
Q

What is hyperglycaemia

A

Permanent high glucose concentrations can lead to organ damage

30
Q

Advantages go using GM bacteria to produce insulin

A

Human insulin produced in pure form |(|decreased chance of causing allergic reaction)
Insulin produced in higher quantities
Production costs are cheaper

31
Q

Potential use of stem cells in diabetes treatment

A 
Totipotent stem cells have potential to grow into any type of body cells 
Stem cells would be taken from embryos (potential human life)
// embryos used would have been destroyed as 'spare' embryos from infertility treatment ]=
32
Q

Benefits of stem cells treatment

A

Small no. of embryos used for lots of Px
Px don’t need to inject insulin
Decreased chance of rejection from transplant

33
Q

Regulation of insulin levels (beta cells)

A
  1. K+ channels on plasma men open, K+ diffuses (facilitated) out, giving resting mem potential of -70mV
  2. glucose enters cell through glucose transporter proteins when levels are high
  3. glucose phosphorylated by enzyme glucokinase. Metabolised by ATP
  4. K+ channels close when ATP levels are too high
  5. K+ cannot diffuse out= mem potential= -30mV
  6. V-gated Ca2+ channels open in response to mem potential change, Ca2+ enter cell
  7. Ca2+ cause vesicles containing insulin move and fuse with mem, release insulin
    EXOCYTOSIS
34
Q

Similarities between release of insulin from beta cells and transmission of nerve impulse

A

V-gated calcium channels
Vesicles
-70mV resting potential
Exocytosis

35
Q

Differences between release of insulin from beta cells and transmission of nerve impulse

A

Different enzymes

Insulin released into bloodstream =, acetylcholinesterase into synapse

36
Q

Response to high glucose levels

A

Beta cells
Insulin secreted
Targets all cells
Increases glucose transporter proteins on mem
Glycogensis- glucose converted to glycogen in liver
Glucose converted into fats
Glucose for respiration

37
Q

Response to low blood glucose levels

A

Alpha cells
Glucagon sevcreted
Targets liver and fat cells
Glycogenolysis- glycogen-> glucose in liver + released into bloodstream
Gluconeogenesis- amino acids + glycerol converted into glucose in the liver
Fatty acids used in respiration

38
Q

What are insulin and glucagon

A

Antagonistic- have opposite effects on glucose concentrations
Inhibit effects of opposing hormone

OCR BIOLOGY (MODULE 5) (7 decks)

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