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George Biology > Hormonal communication chp 14 > Flashcards

Hormonal communication chp 14 Flashcards

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1
Q

what system in the body uses hormones

A

the endocrine system

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2
Q

what is the endocrine system made up of

A

endocrine glands

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3
Q

what are the major endocrine glands in the human body

A
  • pituitary gland
  • thyroid gland
  • adrenal gland
  • pineal gland
  • thymus
  • pancreas
  • ovary
  • testis
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4
Q

what are some examples of hormones produced by the pituitary gland

A
  • growth hormone (controls growth of bones and muscles)
  • anti-diuretic hormone (increases reabsorption of water in kidneys)
  • gonadotrophins (controls development of testes and ovaries)
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5
Q

what does the thyroid gland produce

A
  • thyroxine (controls rate of metabolism and rate that glucose is used up in respiration)
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6
Q

what does the adrenal gland produce

A
  • adrenaline (increases heart and breathing rate, raises blood sugar level)
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7
Q

what hormone does the testis produce

A
  • produces testosterone (controls sperm production and secondary sexual characteristics)
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8
Q

what does the pineal gland produce

A
  • produces melatonin (affects reproductive development and daily cycles)
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9
Q

what does the thymus produce

A

produces thymosin (promotes production and maturation of white blood cells)

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10
Q

what does the pancreas produce

A

produces insulin and glucogon

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11
Q

what hormones do the ovaries produce, what are there function

A
  • oestrogen (controls ovulation and secondary sexual characteristics)
  • progesterone (prepares the uterus lining for receiving an embryo)
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12
Q

what are the 2 different types of hormones

A

steroid and non-steroid hormones

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13
Q

what is the difference between steroid and non-steroid hormones and why is this

A

steroid hormones are lipid soluble while non-steroid hormones are not as they are hydrophilic

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14
Q

how do steroid hormones actually work

A
  • they pass through lipid component of cell membrane and bind to steroid hormone receptors (may be present in cytoplasm or nucleus) to form hormone-receptor complex (acts as transcription factor which facilitates or inhibits transcription of specific gene)
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15
Q

how do non-steroid hormones work

A
  • bind to specific receptors on cell surface membrane of target cell
    ^ this triggers cascade reaction mediated by second messengers
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16
Q

what is an example of a steroid and non-steroid hormone

A
  • oestrogen is an example of a steroid hormone
  • adrenaline is an example of a non-steroid hormone
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17
Q

what are the pros and cons of hormonal communication compared to neuronal communication

A

hormonal communication is not as fast as neuronal but the effect of hormonal communication can be much longer lasting

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18
Q

where are the adrenal glands found in the body and what is there basic structure

A
  • 2 small glands located on top of each kidney
  • made up of: adrenal cortex (produces essential hormones such as cortisol) and adrenal medulla (produces non-essential hormones e.g. adrenaline)
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19
Q

what are the 3 main types of hormones produced by the adrenal cortex

A
  • cortisol hormones which help regulate metabolism
  • aldoosterone help control blood pressure via ions regulations
  • androgens, male and female sex hormones
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20
Q

what hormones are secreted from the adrenal medulla

what is their effect

A
  • adrenaline (increases heart rate and blood glucose levels)
  • noradrenaline (increases heart rate , widens pupils & air passages and narrows blood vessels in non-essential organs)
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21
Q

where is the pancreas found in the body

A

found in upper abdomen, behind the stomach

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22
Q

what are the 2 main roles of the pancreas

A

as an:
- exocrine gland-to produce enzymes and release them via a duct into the duodenum
- endocrine gland-to produce hormones and release them into the blood

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23
Q

what are the 3 important types of enzymes released by the pancreas
where are they released

A
  • amylase (breaks down starch into simple sugars)
  • proteases (break down protein into amino acids)
  • lipases (break down lipids into fatty acids and glycerol)
  • released into the top of the small intestine, the duodenum
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24
Q

what is the endocrine tissue within the pancreas called and what does it secrete

A
  • islets of langerhans
  • responsible for producing insulin and glucagon, secrete directly into blood stream
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25
Q

what are the exocrine and endocrine parts of the pancreas

what do they look like under a microscope

A
  • islets of langerhans (lightly stained) = endocrine
  • pancreatic acini (darker stained) = exocrine
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26
Q

what are the 2 difference types of cells found within the islets of langerhans and what do they produce

what would they appear like on a micrograph

A
  • α (alpha) cells - these produce and secrete glucagon
  • β (beta) cells - these produce and secrete insulin
  • alpha cells are larger and more numerous than beta cells within an islet
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27
Q

what does lysis, Neo and genesis mean

A
  • lysis - means splitting
  • neo - means new
  • genesis - means birth/origin

glycogenolysis means the splitting of glycogen

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28
Q

what is the normal level of blood glucose

A

90 mg cm^-3

29
Q

what can increase blood glucose concentration

A
  • diet (starch and sucrose rich food will increase your blood glucose concentration)
  • glycogenolysis
  • gluconeogenesis
30
Q

what is glycogenolysis

where is glycagon stored

A
  • glycogen stored in liver and muscle cells is broken down into glucose,
    ^releases into blood stream increasing blood glucose concentration
31
Q

what is gluconeogenesis

A
  • production of glucose from non-carbohydrate sources
    ^liver can make glucose from glycerol and amino acids
    ^released into bloodstream
32
Q

what can decrease blood glucose concentration

A
  • respiration
  • glycogenesis
33
Q

How can respiration decrease blood glucose concentration

A
  • glucose in blood is used by cells to release energy
    ^ during exercise more glucose is needed to generate more energy In order for muscles to contract
34
Q

How can glycogenesis decrease blood glucose concentration

A
  • production of glycogen
    ^when blood glucose is too high, excess glucose is converted into glycogen which is stored in liver
35
Q

what do beta cells in the islets of langerhans do when blood glucose concentration is high

A

beta cells detect rise in concentration and secrete insulin in response

36
Q

How does insulin actually work with cells

A
  • insulin binds to glycoprotein receptor on plasma membranes, causes changes in tertiary structure of glucose transport protein channels
    ^channels open allowing more glucose to enter cell
  • can also activate enzymes within cells to convert glucose to glycogen and fat
37
Q

how does insulin lower blood glucose concentration

Processes

A
  • increasing rate of absorption of glucose by cells (skeletal muscles particularly)
  • increasing respiratory rate of cells
  • increasing rate of glycogenesis (removal of glucose from bloodstream)
  • increasing the rate of glucose to fat conversion
  • inhibiting the release of glucagon alpha cells in islets of langerhans
38
Q

what type of system ensures that insulin levels are at the correct level

A

negative feedback system

39
Q

how does glucagon raise blood glucose concentration

processes

A
  • glycogenolysis
  • reducing the amount of glucose absorbed by the liver
  • increasing gluconeogenesis
40
Q

what is the mechanism for how insulin is secreted

A
  • 1) at normal BGC , potassium channels in membrane of B cells are open and K+ ions diffuse out of cell (inside of cell is at potential of -70mV with respect to outside cell)
  • 2) when BGC rises, glucose enters cell by glucose transporter
  • 3)glucose is metabolised inside mitochondria = production of ATP
  • 4)ATP binds to potassium channels, causes them to close (known as ATP-sensitive potassium channels)
  • 5)As K+ can no longer diffuse out of cell, potential difference reduces to -30mV, depolarisation occurs
  • 6)Depolarisation causes voltaged-gated calcium channels to open
  • 7)Ca 2+ enter cell and causes secretory vesicles to release insulin by exocytosis

BGC = blood glucose concentration

41
Q

what is diabetes

A

They are unable to metabolise carbohydrates properly, in particular glucose

42
Q

what is hyperglycaemia

A

sustained high blood glucose concentration

43
Q

what are the differences between type 1 and 2 diabetes

functionally

A
  • type 1 diabetes the beta cells in the islets of lagerhans do not produce insulin
  • type 2 the person either cannot produce enough insulin or the persons cells do not respond properly to insulin (often due to glycoprotein insulin receptors on cells not working properly)
44
Q

How does type 1 diabetes come about

A
  • there is evidence to suggest that an autoimmune response attacks the individuals beta cells in the islets of langerhans
45
Q

How does type 2 diabetes come about

A
  • as a result of excess body weight, physical inactivity and habitual, excessive overeating of refined carbohydrates
46
Q

what are some common symptoms of diabetes

A
  • high blood glucose concentration
  • glucose present in urine
  • excessive need to urinate
  • excessive thirst
  • constant hunger
  • weight loss
  • blurred vision
  • tiredness
47
Q

How can type 1 diabetes be controlled

A

they need to regularly test their blood glucose level (pricking finger and using machine) and then can injection the correct dose of insulin based on the results

48
Q

what is hypoglycaemia

A

sustained very low blood glucose concentration

49
Q

how can type 2 diabetes be controlled

A
  • they have to regulate there carbohydrate intake (diet) and match this to there exercise levels
  • in some cases drugs such as insulin stimulating drugs and drugs that slow down the rate at which the body absorbs glucose from the intestine are used
  • insulin injections may also be used
50
Q

what are the advantages of using genetically modified bacteria to synthesis medicinal insulin

A
  • human insulin is produced in a pure form (less likely to cause allergic reaction)
  • insulin can be produced in much higher quantities
  • production costs are much cheaper
  • peoples concerns over using animal products in humans are overcome
51
Q

what are the advantages of using stem cells over current therapies

A
  • donor availability would not be an issue - stem cells could produce an unlimited source of new beta cells
  • reduced likelihood of rejection as embryonic stem cells are usually not rejected (stem cells can also be made by somatic cell nuclear transfer)
  • people no longer have to inject themselves with insulin
52
Q

what 2 systems are used to bring about the flight or fight response and what communicates to the both of them

A

the hypothalamus communicates with the sympathetic nervous system and adrenal-cortical system

53
Q

what is the sympathetic nervous systems role in the flight or fight response

A

sends out impulses to glands and smooth muscles and tells adrenal medulla to release adrenaline and noradrenaline into the bloodstream

54
Q

how does the hypothalamus play a role in the flight or fight response

A

The pituitary gland is stimulated by the hypothalamus and ACTH is released into the bloodstream which travels to the adrenal cortex which stimulates the secretion of stress hormones

55
Q

what are some physical responses of the flight and fight response and what is there purpose

A
56
Q

How does adrenaline act upon its target cell

A
57
Q

what is one of adrenalines main functions during the flight or fight response

A

triggers the liver the cells to undergo glycogenolysis

58
Q

what does adenylyl cyclase actually do as a secondary messenger

A

triggers the conversion of ATP into cyclic adenosine mono-phosphate (cAMP) on the inner surface of the cell membrane in the cytoplasm

59
Q

what does the increase in the cAMP levels during the flight or fight response do

A
  • activates specific enzyme called protein kinases which phosphorylate and hence activate other enzymes
  • for this example enzymes are activated which trigger the conversion of glycogen into glucose
60
Q

what are the 2 centres in the medulla oblongata that are linked to the sinoatrial node in the heart

A
  • one centre increases heart rate by sending impulses through the sympathetic nervous system (transmitted by accelerator nerve)
  • another decreases heart rate by sending impulses through the parasympathetic nervous system (transmitted by the vagus nerve)
61
Q

what are the 2 receptors that provide information to the medulla oblongata that affects heart rate

A
  • baroreceptors (pressure receptors)
  • chemoreceptors (chemical receptors, sensitive to chemicals such as carbon dioxide)
62
Q

where are baroreceptors located

A

present in the aorta, vena cava and carotid arteries

63
Q

where are chemoreceptors

A

in the aorta, carotid artery (found in the neck and supplies blood to brain) and the medulla

64
Q

what are chemoreceptors sensitive to and how does it respond to these changes

A
  • changes in pH level of the blood (if carbon dioxide level in blood increases pH of blood decreases due to carbonic acid forming)
  • if decrease in pH is detected then an increase in heart rate is triggered to allow carbon dioxide to be exhaled
65
Q

how does the baroreceptor respond to a change in pressure

A

if a change in blood pressure is detected, an impulse is sent to the centres in the medulla oblongata that effect heart rate, impulses are then sent to the heart along the sympathetic or parasympathetic neurones to the SAN in the heart

66
Q

How does adrenaline speed up heart rate

A

by increasing the frequency of impulses produced by the SAN

67
Q

what is the function of insulin

A

converts excess glucose into glycogen in the liver

68
Q

what is the function of glucagon

A

glucagon converts glycogen back into glucose in the liver

George Biology (71 decks)

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