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Physiology > Physiology wk2 > Flashcards

Physiology wk2 Flashcards

1
Q

what is neuroendocrinology

A

the combination of the nervous system + endocrine system

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2
Q

what does the nervous system do

A

uses neurotransmitters to relay messages from one nerve tissue to another, or nerve to a tissue

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3
Q

how do hormones act

A

they are released into the blood by endocrine glands, they then bind to specific receptors to exert effect

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4
Q

what affects the effect of hormones on a tissue

A

plasma concentration, it alters their access to target tissue by either allowing greater access or restricts it

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5
Q

what is plasma concentration determined by

A

Rate of secretion of hormones from endocrine gland
Rate of metabolism/excretion of hormone
Quantity of the transport protein
Changes in plasma volume

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6
Q

what two types of influence do endocrine glands cause

A

they can either interfere or reinforce

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7
Q

what does the magnitude of effect depend upon

A

Concentration of hormones
Number of target receptors
Affinity of receptor to hormone
plasma concentration/volume

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8
Q

what is down-regulation

A

decrease in receptors in response to high concentration of hormone

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9
Q

what is up-regulation

A

increase in receptor number in response to low concentration of hormone

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10
Q

what is the mechanism of steroid hormone action

A
  1. Hormone passes through membrane
  2. Hormone binds to receptor protein in cytoplasm/nucleus
  3. Hormone-receptor complex binds to hormone response element on DNA regulating gene transcription
  4. Protein synthesis
  5. Change in protein synthesis is cellular response
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11
Q

what are the steps of glucose membrane transport mechanism

A

1.Insulin binds to the extracellular domain of the alpha-subunit of insulin receptor
2.The beta-subunit of one insulin receptor phosphorylates the other, allowing insulin response proteins to be activated
3.Phosphorylated insulin response proteins activate glycogen synthase
4.Glycogen synthase converts glucose into glycogen

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12
Q

what is the hypothalamus

A

this is the sector of the brain that controls secretion of the pituitary glands

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13
Q

what hormones does the anterior pituitary gland secret

A
  • Adrenocorticotropic hormone (ACTH)
  • Follicle-stimulating hormone (FSH)
  • Luteinizing hormone (LH)
  • Melanocyte-stimulating hormone (MSH)
  • Thyroid-stimulating hormone (TSH)
  • Growth hormone
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14
Q

what hormones does the posterior pituitary gland secret

A

*Oxytocin
*Antidiuretic hormone (ADH) – reduces water loss from the body, release is caused by high plasma osmolality and low plasma volume

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15
Q

what does aldosterone do

A

helps to regulate your blood volume/pressure by managing levels of Na and K in blood

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16
Q

how is aldosterone activated

A
  1. low plasma volume and blood pressure
  2. secretes renin at the kidney
  3. activates ANGIOTENSIN 1
  4. acted on by ACE (angiotensin converting enzyme)
  5. activates ANGIOTENSIN 2
  6. triggers aldosterone
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17
Q

what is the definition of bioenergentics

A

the flow and exchange of energy within a living system, conversion of substance into useable energy

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18
Q

what is the definition of metabolism

A

the sum of all chemical reactions within the body

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19
Q

what are the two types of metabolism

A

anabolic - synthesis of molecules
catabolic - breakdown of molecules

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20
Q

what does endergonic mean

A

requires energy to be added to the reactants (pushing a ball up a hill)

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21
Q

what does exergonic mean

A

this releases energy (pushing a ball down a hill)

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22
Q

what is special about coupled reactions

A

they use the liberation of energy from an exergonic reaction to drive and endergonic reaction
oxidation-reduction reactions are always coupled

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23
Q

what is oxidation

A

the removal of an electron

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24
Q

what is a reduction reaction

A

the gaining of an electron

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25
Q

what do enzymes do

A

lower activation energy by providing an alternative pathway to accelerate chemical reactions

26
Q

what are the 4 main type of enzymes and what do they do

A

Kinase – adds Pi
Dehydrogenases – remove hydrogen atoms
Oxidases – catalyse oxidation-reduction reactions involving o2
Isomerases – rearrangement of the molecules structure

27
Q

what factors affect enzymes activity

A

temp
pH
substrate availability

28
Q

brief summary of glycolysis

A

glucose is phosphorlayted into pyruvate to go to krebs, H+ ions taken up by NAD
rate limiting enzyme - phosphofructokinase

29
Q

brief summary of anaerobic glycolysis

A

glucose is phosphorylated into pyruvate, no O2 available to take up H+ ions, they bond with pyruvate to form lactate
rate limiting - lactate dehydrogenase

30
Q

brief summary of krebs

A

pyruvate into acteyl coa, this is oxidised to form atp but more importantly FADH and NADH fro ETC
rate limiting enzyme - isocitrate dehydrogenase

31
Q

breif summary of ETC

A

electrons shot into inter-membrane space to create a gradient, come back down gradient making energy, o2 as last electron acceptor to form h20
rate limiting enzyme - cytochrome oxidase

32
Q

what is an oxygen deficit

A

when we use anaerobic pathways to make energy as oxygen supply cant meet demand at start of exercise

33
Q

what does o2 deficit lead to

A

EPOC - excess post exercise oxygen consumption

34
Q

what happens in the rapid phase of epoc

A

resynthesis of pc
replenish muscle myoglobin and haemoglobin o2 stores

35
Q

what happens in slow phase of epoc

A
  • Elevated HR and breathing increases
  • Elevated body temp to increase metabolic rate
  • Elevated blood levels of epinephrine and norepinephrine to increase metabolic rate
  • Conversion of lactic acid to glucose - cori cycle
36
Q

why do endurance trained have less o2 deficit

A
  • Greater regional blood flow
  • Increased cellular adaption/efficiency
  • Increased mitochondrial volume
37
Q

How do you calculate RER

A

vCO2 divided by vO2

38
Q

what does RER tell us

A

tells us how hard they’re working and thus what substrate they’re using to provide energy.
RER = 0.7 = FATS
RER = 1.0 = CHO

39
Q

what factors affect what fuel we use

A

exercise intensity
exercise duration

40
Q

what is beta oxidation

A

the process of converting FFA into acetyl coA

41
Q

at what intensities do we use what fuels

A

lower intensity and duration we use fats, as we increase both we use CHO
due to more recruitment of fast twitch fibers that use glycolytic enzymes
due to high epinephrine that stimulates glycolysis

42
Q

what happens over a long duration event in terms of fuels

A

at first we will use CHO stores as it’s more energy efficient to break these down, however as time goes on and these run out we will switch to fats as fuels
due to increased lipolysis stimulatedby high levels of epinephrine, norepinephrine and glucagon

43
Q

what is the lactate threshold

A

when blood lactate levels reach 4mmol/L, occurs at around 60% of vO2 max. Also called OBLA

44
Q

possible reasons for lactate threshold

A

lower muscle oxygen
accelerated glycolysis
recruitment of fast twitch fibers
reduced rate of lactate removal from the blood

45
Q

what is the lactate shuttle

A

where lactate is produced in the muscle and transported to the liver to go through the Cori cycle

46
Q

what causes DOMS

A

due to microscopic tears in muscle fibers leading to inflammation and edema (NOT DUE TO LACTIC)

47
Q

name the endocrine glands

A
  • Hypothalamus and pituitary glands
  • Thyroid and parathyroid
  • Adrenal glands
  • Pancreas
  • Testes and ovaries
48
Q

how is plasma glucose maintained through fasting or exercise

A
  1. Mobilization of glucose from liver glycogen stores
  2. mobilization of FFA from adipose tissue
  3. gluconeogenesis from amino acids, lactic acid and glycerol
  4. blocking the entry of glucose into cells
49
Q

what hormones control permissive or slow acting processes

A

thyroxine
cortisol
GH

50
Q

what hormones control fast acting processes

A

epinephrine
norepinephrine
insulin
glucagon

51
Q

what do thyroid hormones do

A

influences the number of receptors on the surface
increases the affinity of receptor to the hormone

52
Q

what does T3 do

A

enhances the effect of epinephrine to mobilize FFA from adipose tissue

53
Q

what does growth hormone do

A
  • Increases amino acid take up and protein synthesis
  • Spares plasma glucose – reduces use of plasma glucose, increases gluconeogenesis, mobilizes fatty acids from adipose tissue
54
Q

what does cortisol do

A
  • Steroid hormone derived from cholesterol and secreted from adrenal cortex
  • Stimulated by stress (adrenocorticotropic hormone) and exercise
  • Contributes to maintenance of plasma glucose
  • Conc peaks in the morning and drops throughout the day
  • Proportional to increase in exercise intensity – mediated through slow process fo DNA transcription and translation to protein synthesis, thus may be related to tissue damage
55
Q

what does the word catecholamines refer to

A

adrenalin (epinephrine/norepinephrine)

56
Q

what effect can e/ne have upon tissues

A

increases all:
hr
glycogenolysis
lipolysis
vasodilation
vasoconstriction

57
Q

what happens to NE and E during exercise

A

it increases
however in endurance exercise it causes a rapid decrease to a fixed intensity bout

58
Q

what does the pancreas do

A
  • Controls both exocrine and endocrine functions
  • Secretes counter-regulatory hormones from the ilses and Langerhans
  • Insulin from beta-cells
  • Glucagon from alpha-cells
59
Q

what happens to conc of insulin during moderate intensity exercise

A

drops by 50% to favour glucose breakdown from the liver and FFA from adipose tissue

60
Q

what is the main stimulus for change in insulin and glucagon

A

plasma glucose levels

61
Q

why does FFA oxidation lower during exercise

A
  • High levels of lactic
  • Elevated H+ conc and inhibits HSL
  • Inadequate blood flow to adipose tissue
  • Insufficient albumin to transport FFA in plasma

epinpehrine stimulates glycolysis
fast twitch fiber recruitment and use of more glycolytic vs lipolytic enzymes

Physiology (13 decks)

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