14 - Hormonal Communication Flashcards

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1
Q

What are hormones?

A

Chemical messengers which travel in the blood to activate target cells

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2
Q

What are endocrine glands?

A

Ones which secrete hormones into the blood to reach the target organ

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3
Q

What are 8 examples of endocrine glands?

A
  1. Endocrine pancreas 2. Testes 3. Ovaries 4. Pituitary gland 5. Thyroid gland 6. Pineal gland 7. Adrenal gland 8. Thymus
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4
Q

What are gonads?

A

Reproductive organs

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5
Q

What are 3 examples of hormones made by the pituitary gland?

A
  1. Growth hormone 2. ADH 3. Gonadotropins
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6
Q

What does growth hormone do?

A

Stimulates bone and muscle growth

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7
Q

What does ADH do?

A

Increases water reabsorption in the kidneys

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8
Q

What do gonadotropins do?

A

Control development of the sex organs

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9
Q

What does the pineal gland produce?

A

Melatonin

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10
Q

What does melatonin do?

A

Controls sleep/wake cycles and affects reproductive development

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11
Q

What does the Thyroid gland produce?

A

Thyroxine

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12
Q

What does thyroxine do?

A

Controls rate of metabolism and rate at which glucose is used up in respiration, as well as promoting growth

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13
Q

What does the thymus produce?

A

Thymosin

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14
Q

What does thymosin do?

A

Promotes the proliferation and maturation of T cells

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15
Q

What 2 hormones are produced by the endocrine pancreas?

A

Glucagon and insulin

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16
Q

What hormone do the testes produce?

A

Testosterone

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17
Q

What does testosterone do?

A

Influences sperm cell development and also produces the male secondary sex characteristics

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18
Q

What 2 hormones do the ovaries produce?

A
  1. Estrogen 2. Progesterone
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19
Q

What does estrogen do?

A

Creates secondary sex characteristics in the female and controls ovulation

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20
Q

What does progesterone do?

A

Maintains lining of uterus

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21
Q

What are the 2 types of hormone?

A

Steroid and non-steroid

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22
Q

What are target cells?

A

Cells that have receptors for a particular hormone

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23
Q

What is an example of a steroid hormone?

A

Estrogen

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24
Q

What is an example of a non-steroid hormone?

A

Adrenaline

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25
Q

What differentiates how steroid and non-steroid hormones behave?

A

Steroid hormones are lipid-soluble and pass through the plasma membrane of the target cells, but non-steroid hormones are not lipid-soluble and so must bind to receptors on their cell surface membrane

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26
Q

What happens when a steroid hormone passes into a target cell?

A

It binds to a receptor to form a hormone-receptor complex, which then acts as a transcription factor for a specific gene

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27
Q

What 2 places in the cell can steroid hormone receptors be found?

A

Nucleus and cytoplasm

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28
Q

How do non-steroid hormones work?

A

They bind to a cell-surface receptor which causes a cascade reaction within the cell mediated by secondary messengers

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29
Q

Which of neuronal and hormonal communication is quicker?

A

Neuronal

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30
Q

Which of neuronal and hormonal communication is longer-lasting?

A

Hormonal

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31
Q

What is the difference between hormonal and neuronal communication in terms of how widespread the response is?

A

Neuronal tends to be localised, hormonal is much more widespread (although limited to target organs)

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32
Q

What is the difference between hormonal and neuronal communication in terms of whether the response is temporary or permanent?

A

Neuronal tends to be temporary, hormonal can be temporary but can also be permanent

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33
Q

What is the difference between hormonal and neuronal communication in terms of the reversibility of the response?

A

Neuronal tends to be reversible, hormonal can have irreversible effects

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34
Q

What are the 3 parts of the adrenal gland?

A

Capsule, cortex, medulla

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35
Q

Where in the body are the adrenal glands found?

A

On top of the kidneys

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36
Q

What is the functional of the adrenal glands’ capsule?

A

It is a protective membrane layer

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37
Q

What 3 types of hormone are produced by the adrenal cortex?

A
  1. Glucocortisoids 2. Mineralocortisoids 3. Androgens
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38
Q

What androgens are produced by the adrenal cortex?

A

Small amounts of the opposite sex hormone

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39
Q

What regulates the release of glucocortisoids?

A

The hypothalamus

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40
Q

What 3 things do glucocortisoids regulate?

A
  1. Metabolism 2. Blood pressure 3. Immune response
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41
Q

What are 2 examples of glucocortisoids?

A

Cortisol and corticosterone

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42
Q

What controls the release of aldosterone from the adrenal cortex?

A

The kidney

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43
Q

What is the main mineralocortisoid produced by the adrenal cortex?

A

Aldosterone

44
Q

What does aldosterone do?

A

Regulates the amount of salt and water in bodily fluids

45
Q

What 2 hormones are released by the adrenal medulla?

A

Adrenaline and noradrenaline

46
Q

What 3 things does adrenaline do?

A

Increases heart rate, elevates blood pressure, boosts energy supplies by causing glycogen to be converted into glucose in the liver

47
Q

What 4 things does noradrenaline do?

A

Narrows blood vessels, widens airways, increases heart rate, widens pupils

48
Q

What is the exocrine function of the pancreas?

A

Produces digestive enzymes and alkaline pancreatic juices, then secretes them to the duodenum via the pancreatic duct

49
Q

What is the duodenum?

A

First part of the small intestine

50
Q

What is is the difference between pancreatic and salivary amylase, or between pancreatic or stomach proteases?

A

Pancreatic ones work at a higher pH

51
Q

What is most of the pancreas made up of?

A

Exocrine glandular tissue

52
Q

What 3 types of digestive enzymes does the pancreas produce?

A
  1. Amylases 2. Proteases 3. Lipases
53
Q

What are the endocrine areas of the pancreas called?

A

Islets of Langerhans

54
Q

What 2 types of cell make up the Islets of Langerhans?

A

Alpha and beta cells

55
Q

What do alpha cells produce?

A

Glucagon

56
Q

What do beta cells produce?

A

Insulin

57
Q

What are the exocrine areas of the pancreas known as?

A

Pancreatic acini

58
Q

How do the Islets of Langerhans and Pancreatic Acini differ under staining?

A

Islets are more lightly stained, Acini more darkly

59
Q

What shape are the Pancreatic Acini?

A

Small, berry-like clusters

60
Q

What shape are the Islets of Langerhans?

A

Large and spherical

61
Q

What 2 hormones control blood glucose levels?

A

Insulin and glucagon

62
Q

What 3 things can increase blood glucose levels?

A
  1. Diet 2. Gluconeogenesis 3. Glycogenolysis
63
Q

What is glycogenolysis?

A

Breakdown of glycogen to glucose

64
Q

What is gluconeogenesis?

A

The formation of glucose by non-glucose precursors such as proteins and fats.

65
Q

What is glycogenesis?

A

Formation of glycogen from glucose

66
Q

What is the only major cell type without an insulin receptor?

A

Erythrocyte

67
Q

What 2 things can decrease blood glucose levels?

A
  1. Glycogenesis 2. Respiration
68
Q

What 2 things happen when insulin binds to a glycoprotein receptor?

A
  1. Causes a change in the tertiary structure of glucose channel proteins, causing them to open and allow more glucose into the cell 2. Activates enzymes in some cells to convert glucose to glycogen and lipids
69
Q

Why does insulin have to be constantly secreted?

A

It is broken down by enzymes in liver cells, so needs to be constantly secreted to maintain its effect

70
Q

What type of feedback regulates insulin and glucagon levels in the blood?

A

Negative feedback

71
Q

In what 5 ways does insulin lower blood glucose levels?

A
  1. Increases rate of glucose absorption by cells 2. Increases respiratory rate of cells 3. Increases rate of glycogenesis 4. Increases rate of glucose to fat conversion 5. Inhibits release of glucagon from alpha cells
72
Q

What are the only cells with glucagon receptors?

A

Fat and liver cells

73
Q

In what 3 ways does glucagon increase blood glucose levels?

A
  1. Glycogenolysis 2. Increasing gluconeogenesis 3. Reducing the amount of glucose absorbed by liver cells
74
Q

What is the mechanism of control of insulin secretion by beta cells?

A
  1. Glucose enters cell via transporter 2. Glucose metabolised in mitochondria, resulting in ATP production 3. ATP binds to ATP-sensitive potassium channels, causing them to close 4. Potassium ions can no longer diffuse out of cell, so potential difference reduced to around -30mV and cell depolarises 5. Depolarisation causes voltage-gated calcium channels to open 6. Calcium ions enter cell and cause release of insulin from secretory vesicles
75
Q

What is the resting potential of a beta cell?

A

-70mV

76
Q

What is hyperglycemia?

A

High blood glucose

77
Q

What is wrong with people who have Type 1 diabetes?

A

They either do not produce any insulin

78
Q

What are the 2 causes of Type 1 diabetes?

A
  1. Genetics 2. Autoimmune response
79
Q

What are 8 common symptoms of diabetes?

A
  1. Blurred vision 2. Tiredness 3. Glucose present in urine 4. Excessive need to urinate 5. High blood glucose 6. Constant hunger 7. Weight loss 8. Excessive thirst
80
Q

What proportion of diabetes sufferers have Type 2 diabetes?

A

90%

81
Q

How quick is the onset of Type 2 diabetes?

A

Slow onset

82
Q

What is wrong with people with Type 2 diabetes?

A

They either do not produce enough insulin or their body’s cells no longer respond to it, often because so many insulin receptors are placed in cell membranes due to constant stimulation

83
Q

What problem underlies both types of Diabetes?

A

The cells cannot take up enough glucose, which remains in the blood

84
Q

What are 2 possible causes of Type 2 diabetes?

A

Poor diet and lack of exercise

85
Q

Can diabetes be cured?

A

No, but it can be treated

86
Q

What are 4 ways of treating Type 1 diabetes?

A
  1. With insulin injections and constant blood glucose monitoring 2. Pancreas transplant 3. Artificial pancreas machine 4. Treatment with stem cells to restore beta cells to pancreas
87
Q

How is Type 2 diabetes managed?

A

Healthy eating, physical activity, and if neither of these work then medication and possibly insulin

88
Q

How was medical insulin initially extracted?

A

From the crushed up pancreases of pigs and cattle

89
Q

What were 3 problems of extracting insulin from animal pancreases?

A
  1. Difficult 2. Expensive 3. Animal insulin could cause allergic reaction in humans
90
Q

What are 4 advantages of producing insulin using genetically modified bacteria?

A
  1. Less allergic reactions 2. Cheaper 3. Can be produced in higher quantities 4. No ethical or religious objections as with using animal products
91
Q

What are 2 problems with doing a pancreas transplant?

A
  1. Lack of donor organs 2. General negatives of need for immunosuppressant drugs
92
Q

What is a disadvantage of using stem cell therapy to treat diabetes?

A

Ethical objections to using embryonic stem cells and thus destroying an embryo

93
Q

What are 3 advantages of using stem cell therapy over current therapy in treating diabetes?

A
  1. Donor availability not an issue 2. No more insulin injections 3. Reduced likelihood of rejection
94
Q

What response can the neuronal and hormonal systems coordinate to produce?

A

Fight or flight response

95
Q

What is the mechanism of action for adrenaline in hepatocytes? (i.e how does secondary messaging system work)

A
  1. Binds to cell surface receptor 2. This causes activation of cell membrane enzyme adenylyl cylase, which stimulates cAMP production 3. cAMP activates other enzymes including protein kinases, which activate further enzymes by phosphorylating them
96
Q

What receptors detect changes in blood pressure?

A

Baroreceptors

97
Q

What part of the nervous system do baroreceptors belong to and why?

A

Parasympathetic, as they detect high blood pressure and act to reduce it

98
Q

What part of the nervous system do chemoreceptors belong to?

A

Sympathetic

99
Q

What part of the brain does information from baroreceptors and chemoreceptors go to to help it regulate heart rate?

A

Medulla

100
Q

How does the medulla control heart rate?

A

By stimulating the SAN

101
Q

How many centres are there in the medulla to control heart rate?

A

Two

102
Q

How do the 2 centres of the Medulla work?

A

One acts via the parasympathetic nervous system, sending signals via the vagus nerve. The other acts via the sympathetic nervous system, sending signals via the accelerator nerve

103
Q

How is a response triggered to increase or reduce heart rate by chemoreceptors?

A

Chemoreceptors detect blood pH, which is affected by carbonic acid (dissolved CO2) levels. If it is too high heart rate is increased, if too low heart rate is decreased

104
Q

How do hormones affect heart rate?

A

They affect the rate at which the SAN produces signals

105
Q

How is a response triggered to increase or reduce heart rate by baroreceptors?

A

If blood pressure is too high or low they send signals to the medulla to reduce or increase heart rate respectively