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Biology > B14 - Hormones, pancreas, diabetes > Flashcards

B14 - Hormones, pancreas, diabetes Flashcards

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1
Q

Define an endocrine gland

A

Specialised cells that secrete chemials(hormones) directly into the blood stream

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2
Q

What does the pituitary gland produce? (1)

A
  • growth hormones
  • anti-diuretic hormone (ADH)
  • gonadotropins (control ovaries and testes development
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3
Q

What hormone does the thyroid gland produce?

A

Thyroxine (controls metabolism, rate of glucose used in resporation, promotes growth)

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4
Q

What hormone(s) does the pancreas produce?

A
  • insulin
  • glucagon
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5
Q

what hormone(s) does the ovary produce?

A
  • oestrogen (controls ovulation & secondary sexual characteristics)
  • progesterone (prepares uterus lining for recieving an embryo)
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6
Q

What hormone does the pineal gland produce?

A
  • melatonin (sleep/daily cycles, effects reproductive development)
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7
Q

What hormone does the thymus gland produce?

A

thymosin (production & maturation of white blood cells)

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8
Q

What hormone does the adrenal gland produce?

A

Adrenaline (increases heart rate, breathing rate, blood sugar levels)

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9
Q

What hormone does the testes produce?

A

Testosterone (control sperms production and secondary sexual characteristic)

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10
Q

what is a steroid hormone?

A
  • small and lipid soluble
  • pass through membrane and binds to steroid hormone receptors
  • form hormone-receptor complex, which acts as a transcription factor (facilitates or inhibits transcription of a specific gene)
    -e.g. oestrogen
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11
Q

What is a non-steroid (protein) hormone?

A
  • large hydrophilic/polar
  • cannot pass through membrane
  • bind to receptors on target cell membrane
  • triggers cascade reaction controlled by secondary messengers

e.g. adrenaline

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12
Q

What is an exocrine gland?

A

Secretes fluid containing digestive enzymes directly in ducts to organs

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13
Q

What is a hormone? How are they transported? (2)

A
  • chemical messenger that carries info to body parts
  • secreted into blood when a gland is stimulated
  • transported in blood plasma
  • diffuses out blood and binds to specific receptors on target cell, which evokes a response.
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14
Q

What do the adrenal glands consist of and where are they located?

A
  • on top of each kidney
  • adrenal medulla
  • adrenal cortex
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15
Q

What types of hormones does the adrenal medulla secrete?

A
  • non essential
  • released when sympathetic nervous system stimulated
  • flight or fight
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16
Q

What are the two main hormones secreted by the adrenal medulla? Explain their functions. (4)

A

Adrenaline:
- Inc heart rate & sends blood to muscles/brain
- Inc blood glucose as converts glycogen to glucose in the liver

Noradrenaline
- works alongside adrenaline in response to stress
- increase heart rate
- pupils widen
- air passage in lungs widen
- blood vessels narrow so higher blood pressure

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17
Q

What types of hormones does the adrenal cortex produce? (1)

A
  • essential/vital to life
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18
Q

Name and explain the role of some hormones secreted by the adrenal cortex. (3)

A

glucocorticoids:
-released by pituitary gland caused by hypothalamus
- e.g. cortisol - regulates metabolism, blood pressure & cardiovascular function in response to stress
- e.g. corticosterone - regulates immune response & suppress inflammatory reactions

mineralcorticoids:
- aldesterone helps control blood pressure as maintains blood water balance.

Androgens:
- small amounts of sex hormones released
- small impact compared to larger amounts of hormones e.g. oestrogen but are still important
- important in menopause in women

19
Q

how does the pancreas function as both an exocrine and endocrine gland? (4)

A

Exocrine(majority):
- produce pancreatic juice(alkaline) containing digestive enzymes
- secreted into pancreatic duct
- released into duodenum (top of small intestine)

Endocrine:
- produce hormones glucagon and insulin
- islets of langerhans = regions of endocrine tissue within exocrine tissue.

20
Q

What are islets of langerhans? What do they consist of?

A
  • regions of endocrine tissue within the exocrine tissue.
  • alpha cells: produce & secrete glucagon
  • beta cells: produce & secrete insulin
21
Q

Name 3 digestive enzymes secreted by the pancreas (3)

A

Amylase:
Break starch into simple sugars

Protease:
Break protein into amino acids e.gm trypsin

Lipase:
Break lipids into fatty acids and glycerol

22
Q

What processes decrease blood glucose concentration? (2)

A

Respiration: glucose used to release energy/ATP. Exercising uses more glucose as more ATP needed for muscle contraction.

Glycogenesis: glycogen produced from excess glucose in blood and is stored in the liver

23
Q

What processes increase blood glucose concentration?

A

Diet:
- carb rich foods & sweet foods(high in glucose)
- carbs broken down in digestive system and absorbed into bloodstream.

Glycogenolysis:
- glycogen stored in liver & muscle cells.
- breakdown into glucose & absorbed into blood stream.

Gluconeogenesis:
- glucose made from non-carb sources
- e.g. liver makes glucose from glycerol(lipids) and amino acids

24
Q

B cells secrete insulin. How does insulin interact with other cells to encourage glucose uptake? (3)

A
  • Insulin binds to glycoprotein receptor on cell surface.
  • Changes tertiary structure of glucose transport protein channels
  • Channels open so glucose enters the cell.
  • Also activates enzymes to convert glucose to glycogen or fat.
25
Q

How does insulin lower blood glucose levels? (3)

A
  • increase glucose absorption into cells
  • increase respiration rate
  • increase glycogenesis
  • Increase glucose conversion to fat.
  • Inhibit glucagon release from alpha cells
26
Q

Alpha cells secrete glucagon. How does glucagon interact with cells to increase blood glucose levels? (1)

A
  • only fat and liver cells have glucagon receptors.
  • glucagon binds.
27
Q

How does glucagon raise blood glucose levels? (2)

A
  • glycogenesis releases glucose into blood stream
  • reduce amount of glucose absorbed by liver cells
  • gluconeogenesis
28
Q

How is insulin secreted by B cells? (5)

A
  • K+ channels open at normal blood glucose levels, K+ diffuses out, polarised membrane -70mV
  • glucose enters cell via transporter when blood glucose level rises
  • glucose metabolised in mitochondria to produce ATP
  • ATP binds to K+ channels, closing them (ATP-sensitive K+ channels)
  • K+ can’t diffuse out, potential difference reduces to +30mV and membrane becomes depolarised.
  • Depolarisation causes Ca2+ channels open, Ca2+ enter causing vesicles to release insulin via exocytosis.
29
Q

Why are insulin and glucagon antagonistic hormones?

A

Work against each other in a system to maintain blood glucose.

30
Q

Suggest why is blood glucose concentration self-regulating. (1)

A
  • Blood glucose levels determines the amount of insulin or glucagon secreted to lower or increase glucose levels.
  • Not constant: fluctuates around a set point due to negative feedback
31
Q

Suggest why glucose in urine is a symptom of diabetes.

A
  • Insulin function disrupted, blood glucose levels rise (hyperglycaemia)
  • kidney’s can’t filter excess glucose in blood, therefore appears in urine.
32
Q

What is the difference between type I and type II diabetes? (4)

A

type I:
- Unable to produce insulin
- Usually begins in childhood
type II:
- more common
- Insulin produced but glycoprotein receptor doesn’t work properly.
- cells lose responsiveness to insulin = less glucose uptake = high levels in bloodstream
- Risk increases with age.

33
Q

What is the difference between type I and type II diabetes? (4)

A

type I:
- Unable to produce insulin
- Usually begins in childhood
- autoimmune response: T cells attack beta cells so they can’t secrete insulin.
type II:
- more common
- Insulin produced but glycoprotein receptor doesn’t work properly.
- cells lose responsiveness to insulin = less glucose uptake = high levels in bloodstream
- Risk increases with age.

33
Q

What are some risk factors of type II diabetes? (3)

A
  • excess body weight
  • inactivity
  • overeating (carbs)
  • risk increases with age (40+)
  • similar symptoms to type I but less severe and develop slowly.
  • genetics/ more likely inherited
34
Q

What are some common symptoms of diabetes? (4)

A
  • high blood glucose
  • glucose in urine
  • excessive need to urinate
  • excessive thirst
  • weight loss
  • constant hunger
  • blurred vision
  • tiredness
35
Q

Name some treatments for type I (3)

A

Insulin injections:
BUT too much = hypoglycaemia (low bgc)

-regular blood tests e.g. finger pricks, blood drop analysed to find glucose concentration and determine insulin dose.

  • healthy diet
36
Q

Name some treatments for type II (2)

A

Diet & exercise:
- regulate carb intake
- increse exercise

overweight people encourages to lose weight

sometimes diet & exercise not enough, so use drugs to stimulate insulin production (sometimes use insulin injections)

37
Q

Before insulin was medically produced, how was it orignially obtained and what were the problems?

A
  • from pancreas of cows and pigs.
    Problems:
  • hard & expensive
  • Also cause allergic reactions as different to human insulin
38
Q

What is recombinant DNA?

A

DNA altered by adding another source.
- Produces recombinant proteins (RP).

39
Q

What are the advantages of medically produced insulin.

A
  • Identical to human insulin (pure form)
  • Insulin produced in higher quantities
  • cheaper production
  • fewer ethical, religious, moral concerns.
40
Q

what are the issues with pancreatic transplants, despite them being 80% effective?

A
  • Demand outweighs availability
  • large risk with immunosuppressant drugs = susceptible to infection
41
Q

What problem comes with beta cell injections? (1)

A

Immunosuppressant drugs increase metabolic demand, exhausting the cells’ capacity to produce insulin.

42
Q

What concerns are there about stem cell therapy used in diabetes? How are these concerns overcame?

A
  • stem cells likely to be taken from embryo but the embryo must be destroyed
  • ethical concerns surrounding destroying a potential human life

Overcame:
- Use ‘spare’ embryos from infertility treatments/ terminated pregnancies, therefore are usually destroyed anyway.

43
Q

Name some advantages of stem cell therapy.

A
  • no issue of donor availability as unlimited source
  • less chance of rejection
  • human injections would no longer be needed

Biology (20 decks)

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