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sugar Flashcards

1
Q

describe negative feedback

A

As a hormone increases in concentration, it inhibits the release of another hormone.

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2
Q

describe positive feedback

A

As a hormone increases in concentration, it promotes the release of a hormone

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3
Q

what hormones does the anterior pituitary secrete

A 
(FLAGTOP)
FSH – Follicle Stimulating Hormone
LH – Luteinizing Hormone
ACTH – Adrenocorticotropic hormone
GH – Growth Hormone
TSH – Thyroid Stimulating Hormone
O – MelanOcyte stimulating hormone
Prolactin
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4
Q

what hormones does the posterior pituitary secrete

A

ADH/Vasopressin

Oxytocin

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5
Q

describe the male HPG axis

A

LH -> Leydig cells -> Testosterone

FSH -> Sertoli Cells -> Stimulates production of ABP -> Spermatogenesis

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6
Q

describe the female HPG axis

A

LH -> Stimulates ovulation + ovarian follicle maturation + corpus luteum formation.
FSH -> regulates development + growth of ovarian follicle + affects 1st half of menstrual cycle

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7
Q

describe the oestrogen feedback mechanisms on the HPG axis

A

Moderate levels of oestrogen present will exert negative feedback on FSH and LH.
High oestrogen (with low progesterone) exerts positive feedback on LH and FSH.
Oestrogen in the presence of progesterone exerts negative feedback.

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8
Q

describe the HPA axis

A

CRH -> ACTH (corticotrohps) -> Cortisol (ZF of adrenal cortex)

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9
Q

cortisol functions

A

Gluconeogenesis and carbohydrate metabolism

Reduction of inflammation

Proteolysis and lipolysis

Reduction of bone formation, which can lead to osteoporosis over time

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10
Q

describe the HPS axis

A

GHRH -> GH (somatotrophs)

Somatostatin (SST) -/-> GH

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11
Q

what is GH involved in

A 
Skeletal growth and bone density 
Muscle strength 
Protein synthesis 
Glycogenolysis 
Lipolysis
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12
Q

describe the HPT axis

A

TRH -> TSH -> T3/T4

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13
Q

what does TSH (thyroid stimulating hormone) do

A

increase metabolism

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14
Q

describe the release of prolactin

A
  • Suckling causes the release of prolactin as well as TRH.

- Dopamine inhibits release of prolactin

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15
Q

what are the functions of prolactin

A

Initiate milk production in the breasts

Maintain milk production once is has been established

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16
Q

what is the peptide hormone of GnRH

A

FSH + LH

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17
Q

what is the peptide hormone of CRH

A

ACTH

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18
Q

what is the peptide hormone of GHRH

A

GH

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19
Q

what is the peptide hormone of TRH

A

TSH

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20
Q

where is oxytocin synthesised and stores?

A

synthesised in hypothalamus (paraventricular nucleus)

stored in posterior pituitary

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21
Q

what is the function of oxytocin

A

Oxytocin acts on the breasts to allow milk to move through the lactiferous ducts to be expressed through the nipple -> milk ejection during lactation
It also acts on the uterus to cause uterine contractions during labour-> promoting onset of labour
Oxytocin exerts positive feedback on itself

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22
Q

where is ADH synthesised

A

hypothalamus - supraoptic nucleus

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23
Q

how does ADH control osmolality

A

Osmoreceptors in the hypothalamus detect change
ADH binds to V2 receptors on the collecting ducts -> mobilisation of aquaporin 2 (AQP2) + insertion into cell membrane
These allow the passage of water from the collecting duct into the blood to reduce the plasma osmolality -> ↑water reabsorption

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24
Q

how does ADH maintain Blood pressure

A

Maintains BP by acting on smooth muscle cells -> vasoconstriction -> ↑BP

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25
Q

which hormone inhibits GHRH

A

somatostatin

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26
Q

what do the alpha cells of the islets of langerhans secrete

A

glucagon

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27
Q

what do the beta cells of the islets of langerhans secrete

A

insulin

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28
Q

what do the delta cells of the islets of langerhans secrete

A

somatostatin

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29
Q

describe the mechanism of insulin secretion

A
  1. Glucose moves into beta cells via GLUT2 channel
  2. ATP is made
    Closure of ATP-sensitive potassium channels
  3. Depolarisation of the beta cell membrane
  4. Opening of voltage-gated calcium channels
  5. Vesicles containing insulin fuse with the cell membrane
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30
Q

describe the action of insulin in lowering blood glucose

A

Insulin binds to insulin receptors on muscle + fat cells

Triggers intracellular signalling cascade -> mobilisation of intracellular GLUT4 vesicles to cell membrane

GLUT4 vesicle integrates into cell membrane -> ↑number of membrane glucose transporters -> ↑rate of glucose facilitated diffusion into cell -> ↓blood glucose level

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31
Q

describe what happens when glucose levels rise

A

Insulin is released and glucagon release is inhibited

There is increased glycogenesis in the liver and muscles

Gluconeogenesis is inhibited

This reduces the blood glucose level

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32
Q

what level is the thyroid gland situated

A

C5-T1

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33
Q

what divides the thyroid into 2 lobes

A

isthmus

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34
Q

what 2 muscles does the thyroid gland lie between

A

sternohyoid and sternothyroid

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35
Q

how many parathyroid glands are there and where are they located

A

4

posterior surface of the thyroid

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36
Q

what is the blood supply to the thyroid?

A

Superior thyroid arteries
Branch of external carotid artery.
Supply superior + anterior portion of gland
Inferior thyroid arteries
Branching of subclavian artery
Supplies posterior inferior aspect of gland

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37
Q

what protein is produced by the follicular cells

A

thyroglobulin

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38
Q

describe the production of T3 + T4 (ATE ICE)

A

A - (secondary) active transport of iodide via Na/I symporter
T - thyroglobulin is produced in the follicular cells
E - exocytosis of thyroglobulin into the follicular lumen

I - iodination of tyrosine residues on thyroglobulin (thyroid peroxidase) to form monoiodothyronine (MIT) and diiodothyronine (DIT)
C - coupling of MIT and DIT (T3) and DIT and DIT (T4)
E - endocytosis of T3 and T4 into follicular cells. Proteolysis occurs to free T3 and T4 from thyroglobulin

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39
Q

what is the function of T3 and T4

A

increases BMR & important in brain maturation

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40
Q

how does T3 increase BMR

A
  1. T3 -> stimulates carbohydrate absorption in SI , ↑FA release from adipocytes
  2. ↑BMR by providing more energy for metabolism
  3. ↑body temp (homeostasis)
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41
Q

what are the 3 main layers to the skin

A

epidermis
dermis
subcutaneous

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42
Q

what are the 5 layers of the epidermis (top to bottom) (Come, Let’s Get Sun Burnt)

A 
Stratum corneum
Stratum lucidum 
Stratum granulosum 
Stratum spinosum
Stratum basale
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43
Q

what is adhesion in the skin provided by

A

Primary adherens junctions

Desmosomes (stratum spinosum)
Corneo-desmosomes keep corneocytes together

Tight junctions – epithelial layer (stratus granulosum)
Help with providing waterproofing

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44
Q

what is the function of NMF

A

Filaggrin -> natural moisturising factor (NMF)

NMF allows the skin to remain hydrated and maintains the slightly acidic pH the skin has

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45
Q

what is the purpose of the skin being acidic

A

Acidity prevents protease activity to stop the breakdown of corneodesmosomes.

It also aids with the formation of the lipid lamellae.

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46
Q

what is the affect of increased pH on the skin

A

The proteases are no longer inhibited by the low pH so they break down the corneodesmosomes

The increased pH also impairs the formation of the lipid lamellae

This allows the skin cells to move apart which reduces water retention in the skin

Allergens can then penetrate

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47
Q

how do allergens create an inflammatory response

A

Allergen penetrates skin + attracts lymphocyte -> releases inflammatory cytokines -> inflammatory response

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48
Q

what is the cause of red skin

A

dilation of vessels to bring more lymphocytes to area

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49
Q

what is the cause of itchy skin

A

stimulation of proprioceptors by the release of histamine (from mast cells) or thermal/mechanical mediators

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50
Q

what is the cause of dry skin

A

skin cells leaking water

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51
Q

what do sebaceous glands do

A

produce a lipid-rich sebum which protects the hair

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52
Q

how does acne occur

A

Acne occurs when the hair follicle becomes blocked with sebum, skin cells, and bacteria.

Sebum -> free fatty acids (by bacteria) -> inflammation & attraction of neutrophils -> pus formation

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53
Q

what is the automatic nervous supply to the bladder

A

SympathetiC – HypogastriC nerves T12-L2 -> relaxation of detrusor muscle -> urine retention
ParaSympathetic – Pelvic Splanchnic nerves S2-4 -> contraction of detrusor muscle -> micturition stimulation

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54
Q

what is the somatic nervous supply to the bladder

A

Somatic system (voluntary) -> Pudendal nerves S2-4 -> Innervate EUS -> constricts (storage) or relaxes (micturition)

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55
Q

describe the process of bladder filling/ storage

A

Parasympathetic input to detrusor muscles is minimal -> detrusor muscle relaxes.
Strong sympathetic input to Internal urethral sphincter + Strong somatic motor neuron input to External urethral sphincter -> Both Sphincters closed
This allows the bladder to expand to prevent an increase in pressure as the volume increases (stress-relaxation phenomenon)

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56
Q

describe the bladder stretch reflex arc

A

Bladder fills and stretches -> activating stretch receptors
Afferent sensory nerves transmit signal to brain
Interneurons relay signal to parasympathetic efferent nerves (pelvic nerve)
Contracts detrusor muscle -> stimulate micturition

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57
Q

describe the mechanism of voiding

A

Detrusor muscle contracts to increase the pressure in the bladder
Internal urethral sphincter relaxes
Once it’s appropriate to void, the external urethral sphincter will be consciously relaxed to allow voiding

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58
Q

what part of the adrenal gland secretes cortisol

A

zona fasciculata

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59
Q

what part of the adrenal gland secretes androgens

A

zona reticularis

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60
Q

what part of the adrenal gland secretes mineralocorticoids (aldosterone)

A

zona glomerulosa

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61
Q

what does the adrenal medulla secrete

A

adrenaline

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62
Q

what nerve innervates the external urethral sphincter and what nerve roots does it comprise of

A

pudendal nerve S2-S4

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63
Q

what are the functions of the skin

A 
barrier to infection 
thermoregulation 
protect against trauma 
protection against UV 
vitamin D synthesis 
regulate H2O loss
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64
Q

what are corneocytes filled with

A

NMF

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65
Q

what is desquamation

A

when mature corneocytes are shed from the surface of the stratum corneum

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66
Q

what is the pH of normal skin

A

5.5

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67
Q

what does the lipid lamellae do

A

keep water inside the skin cells

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68
Q

describe the brick wall model

A

bricks = corneocytes
iron rods = corneodesmosomes
cement - lipid lamellae

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69
Q

what is the role of vitamin D for the skin

A

essential in producing the anti-microbial peptides necessary to defend the skin from bacteria and viruses

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70
Q

at what level are the kidneys found

A

T12 & L3

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71
Q

which kidney is lower

A

right - pushed down by liver

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72
Q

where is the hilum of the right kidney

A

L2

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73
Q

where is the hilum of the left kidney

A

L1

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74
Q

what is the cortex of the kidney composed of

A

renal corpuscles (glomerulus & bowman’s capsule) and the proximal and distal convoluted tubule

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75
Q

what is a medullary ray

A

collection of loop of henle tubules in the cortex - concentrate urine. and collecting ducts

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76
Q

what is the medulla of the kidney comprised of

A

no real corpuscles or glomeruli

loops of henle, collecting ducts and blood vessels

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77
Q

describe the composition of the kidney pelvis

A

lined by transitional epithelium

tips of medullary pyramids project into pelvis - at this point the pyramids are composed purely of collecting ducts

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78
Q

describe the blood supply to the kidneys

A

renal artery (L1 of aorta) -> segmental -> interlobar -> arcuate-> interlobular -> afferent arterioles

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79
Q

what many nephrons in the kidney

A

1 million in each

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80
Q

what is the role of the renal corpuscle

A

filtering

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81
Q

what is the role of the PCT

A

reabsorbing solutes

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82
Q

what is the role of the loop of henle

A

concentrating urine

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83
Q

what is the role of the DCT

A

reabsorbing more water and solutes

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84
Q

what is the role of the collecting duct

A

reabsorbing water and controlling acid-base & ion balance

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85
Q

what is the glomerular tuft supported by

A

smooth muscle mesangial cells

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86
Q

what are the 3 main functions of the mesangial cells

A
  1. structural support

2, contraction of muscles in the glomerulus to reduce GFR

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87
Q

what are the 2 components of the juxtaglomerular apparatus

A

afferent arteriole & distal convoluted tubule

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88
Q

what is the role of granular cells

A

detect blood pressure and secrete renin in response to a reduction in BP

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89
Q

what do the macula densa do

A

detect sodium levels

90
Q

what do the macula densa cells do when filtration is slow

A

more sodium will absorbed -> macula densa signal to reduce afferent arteriole resistane -> increase GFR

91
Q

what type of epithelium is the PCT composed of

A

cuboidal epithelium

92
Q

what distinguishes PCT from DCT

A

PCT have microvilli - makes surface look fuzzy

93
Q

what epithelium are thin loops of henle composed of

A

simple squamous

94
Q

what epithelium are thick loops of henle composed of

A

low cuboidal

95
Q

what supplies the loop of henle

A

rich vasa recta

96
Q

describe the cells of the DCT

A

cuboidal

contain mitochondria

97
Q

what kind of epithelium lines the collecting ducts

98
Q

what 2 cell types are found in the collecting duct

A

principal cells - respond to aldosterone & ADH

intercalated cells - responsible for exchanging acid for base (alpha - acid , beta - bicarbonate)

99
Q

what epithelium is found in the renal pelvis

A

transitional epithelium

100
Q

describe urothelium (transitional epithelium)

A

surface layer = umbrella cells with tight junctions

basal layer = ceboidal cells

101
Q

describe the muscle layers of the ureter

A

inner - longitudinal

outer - circular

102
Q

what are the layers of the bladder

A 
lamina propria 
muscularis mucosa 
submucosa
muscularis propria
subserosa & serosa
103
Q

what kind of muscle is the internal sphincter made of

A

smooth muscle from bladder

104
Q

what kind of muscle is the external sphincter made of

A

skeletal muscle from pelvic floor

105
Q

describe the female urethra

A

4-5cm long
proximally transitional epithelium
distally squamous epithelium

106
Q

describe the male urethra

A 
20 cm long
prostatic urethra 
membranous urethra (transitional)
penile urethra (pseudostratified proximally, stratified squamous distally)
107
Q

what percentage of cardiac output does each kidney receive

108
Q

what is the total renal blood flow to the kidneys

109
Q

what is the total urine flow

110
Q

what are the 3 components of the glomerular filtration barrier

A
  1. capillary endothelium
  2. basement membrane
  3. epithelium of bowman’s capsule with podocyte foot processes
111
Q

what are the 2 types of nephron and their percentages

A

15% juxtamedullary - renal corpuscle at junction, loop of henle plunges deep into medulla
85% cortical - renal corpuscles in outer cortex

112
Q

what is the order of flow of the glomerular filtrate

A
  1. glomerular capsule
  2. proximal convoluted tubules
  3. nephron loop
  4. distal convoluted tubule
  5. collecting duct
  6. papillary duct
  7. minor calyx
  8. major calyx
  9. renal pelvis
  10. ureter
  11. urinary bladder
  12. urethra
113
Q

how does hydrostatic and oncotic pressure vary along the glomerular capillary

A

hydrostatic - constant

no oncotic in bowman’ capsule - increases as you go along the glomerular capillary

114
Q

GFR

A

the volume of fluid filtered from the glomeruli into bowman’s space per unit time

115
Q

what is GFR determined by

A

net filtration pressure
permeability of the corpuscular membranes
surface area

116
Q

what is used to estimate GFR

A

creatinine

117
Q

afferent arteriole dilation

A

high HP, high GFR

low BP due to low TPR

118
Q

afferent arteriole constriction

A

low HP, low GFR

high TPR, high BP

119
Q

efferent arteriole dilation

A

low HP, low GFR

increased peritubular HP so less reabsorption

120
Q

efferent arteriole constriction

A

high HP, high GFR

low HP in peritubular so higher filtration rate

121
Q

filtration fraction =

A

GFR/ renal plasma flow

122
Q

renal clearance

A

the volume of plasma from which a substance is completely removed by the kidney per unit time
urine concentration x urine volume / plasma concentration

123
Q

tubuloglomerular feedback

A

macula densa detect NaCl arrival

release prostaglandins in response to a reduction in NaCl, triggers granular cells to release renin -> RAAS

124
Q

what are the percentages of body fluid

A

2/3rds ICF

1/3rd ECF (75% interstitial, 25% plasma)

125
Q

what is the major cation of the ECF

126
Q

what is the major cation of the ICF

127
Q

describe the thirst centre

A

stimulated by increase in plasma osmolarity and decrease in ECF volume
stimulates osmoreceptors-> vasopressin secretion -> increased H2O reabsorption

128
Q

where is the most sodium reabsorbed in the nephron

A

proximal tubule 60%

129
Q

briefly describe RAAS

A

angiotensinogen -> angiotensin I (renin)-> angiotensin II (ACE)-> aldosterone secretion ( zona glomerulosa) -> vasoconstrict especially at efferent -> increased GFR -> increased Na reabsorption -> stimulates thirst, vasopressin release and water retention

130
Q

what affect does parathyroid hormone have on the kidneys

A

released in response to low levels of Ca2+-> increases reabsorption -> decreased excretion
stimulatess active form of vit D

131
Q

normal range of pH

132
Q

anion gap equation

A

[Na+] + [K+] - [Cl-] - [HCO3-]

133
Q

what is a normal anion gap

134
Q

causes of respiratory acidosis

A

hypoventilation

COPD

135
Q

causes of respiratory alkalosis

A

hyperventilation

type 1 resp failure

136
Q

causes of metabolic acidosis

A

renal failure

137
Q

causes of metabolic alkalosis

A

vomiting

alkali ingestion

138
Q

where is erythropoietin produced

A

peritubular cells of renal cortex

139
Q

blood supply to adrenal glands

A

superior middle and inferior adrenal artery

140
Q

venous drainage of the adrenal glands

A

right adrenal vein - directly into IVC

left adrenal vein - left renal vein

141
Q

what 5 hormones does the adrenal cortex secrete

A 
aldosterone 
cortisol 
corticosterone 
DHEA
androstenedione
142
Q

what are the 3 layers of the adrenal cortex and what do they secrete (GFR, Makes Good Sex)

A

zona glomerulosa - Mineralocorticoids
zona fasiculata - glucocorticoids
zona reticularis - sex hormones (androgens)

143
Q

embryology of the thyroid gland

A

3-4w epithelial proliferation at base of pharynx - migrate down to below larynx - start producing thyroxine at 18-20w

144
Q

what is stored in the follicle

145
Q

what type of cells are follicular cells

A

simple cuboidal -> become columnar with increased metabolic activity

146
Q

what do parafollicular cells produce

A

calcitonin for Ca2+ homeostasis

147
Q

embryology of the pituitary gland

A

protrusion of ectoderm - rathke’s pouch -> anterior pituitary
posterior is of neural origin

148
Q

embryology of the pancreas

A

2 pancreatic buds fuse
exocrine - after birth
endocrine 10-15 weeks

149
Q

percentage of cells in pancreas

A

98-99% acini - secrete digestive enzymes

1-2% islets of langerhans

150
Q

what are incretins

A

secreted by endothelial cells in GI tract in response to eating - amplifies insulin response to glucose

151
Q

role of glucagon

A

convert glycogen to glucose

form glucose from lactic acids and amino acids

152
Q

role of insulin

A

accelerate diffusion of glucose into cells
speed up conversion of glucose into glycogen
increase uptake of amino acids and increase protein synthesis
speed up FA synthesis
slow glycogenolysis and gluconeogenesis

153
Q

what determines sex

154
Q

male sex development

A

Y -> SRY gene -> wolffian ducts persist, mullerian regress - sertoli cells (MIF)-> testosterone (leydig cells) -> wolffian duct diffferentiates into epididymis, vans deferes, ejaculatory ducts ,seminal vesicles
later - DHT -> penis formation -> testes descend

155
Q

female sex determination

A

no Y -> MIF secreted -> mullerian duct -> fallopian tubes + uterus
wolffian duct degenerates
vagina form

156
Q

when does the second meiotic division occur in males

A

after puberty

157
Q

when does the second meiotic division occur in females

A

after fertilisation

158
Q

what is the epididymis lined by

A

pseudo-stratified columnar epithelium with stereocilia

159
Q

what is expelled during ejaculation

A

60% seminal fluid
30% prostatic
10% sperm & trace of bulbourethral fluid

160
Q

how much sperm is made per gram of testis per second

161
Q

where is mitochondria form in the spermatozoa

162
Q

what is the tip of the nucleus of the spermatozoa covered by

A

acrosome - protein- filled vesicle containing enzymes to penetrate the egg

163
Q

histology of ovary

A

simple cuboidal epithelium

primordial germ cells surrounded by fibroblast- like stromal cells in the cortex

164
Q

what epithelium lines the uterus

A

simple columnar ciliated

165
Q

cervix epithelium

A

simple columnar

166
Q

vagina epithelium

A

moist stratified squamous - keratinised at vulva end

167
Q

how many ovaries are present at birth

A

2-4 million

168
Q

describe the hormone levels at puberty

A

increase in levels of GnRH & GHRH

increase in FSH, LH, GH and sex steroids

169
Q

briefly describe the 2 phases of the menstrual cycle

A
  1. follicular phase
    mature/graffian follicle + secondary oocyte develop
  2. Luteal phase
    after ovulation and lasting until the death of the corpus luteum
170
Q

where are oestrogen and progesterone produced

A

oestrogen - granulosa cells in follicular phase and corpus luteum after ovulation
progesterone - corpus luteum (major source), granulosa + theca (small amounts before ovulation)

171
Q

what is hCG produced by

A

trophoblast cells

172
Q

where does spermatogenesis occur

A

seminiferous tubules

173
Q

what helps to keep the testes temperature low

A

heat exchange via the pampiniform plexus

174
Q

what do the seminiferous tubules converge to form

A

rete testis

175
Q

what is the epididymis lined by

A

pseudo-stratified columnar epithelium with stereocilia

176
Q

summary of path of sperm to outside

A 
seminiferous tubules 
rete testis 
efferent ducts 
epididymis 
vas deferens 
ejaculatory duct 
urethra
penile urethra
177
Q

what forms the blood-testis barrier

A

adjacent sertoli cells joined by tight junctions

178
Q

what do spermatogonia become after they mitotically divide

A

type A: remain outside blood-testis barrier, produce more daughter cells
type B: differentiate into primary spermatocytes

179
Q

what do primary spermatocytes become after meiosis 1

A

secondary spermatocytes

180
Q

what do secondary spermatocytes become after meiosis 2

A

4 spermatids

181
Q

what do spermatids differentiate into

A

spermatozoa

182
Q

how does FSH affect spermatogenesis

A

acts on sertoli cells - stimulate agents to initiate spermatogenesis

183
Q

how does LH affect spermatogenesis

A

acts on Leydig cells to stimulate testosterone - diffuses into seminiferous tubules to facilitate spermatogenesis

184
Q

describe the negative feedback mechanism of testosterone

A

inhibits LH secretion by acting in hypothalamus to reduce GnRH and acts on anterior pituitary to decrease LH response to GnRH

185
Q

what do oogonia differentiate into

A

primary oocytes

186
Q

what do primary oocytes become after meiosis 1

A

secondary oocyte + polar body

187
Q

what does the secondary oocyte become after meiosis 2

A

ovum + polar body

188
Q

what are primordial follicles

A

a primary oocyte surrounded by a single layer of granulosa cells

189
Q

what do granulosa cells secrete

A

oestrogen
small amounts of progesterone
inhibin

190
Q

what happens in the follicular phase of the menstrual cycle (day 1-13)

A

primordial follicles -> primary follicle (zona pellucida forms -> preantral follicle (theca cells - synthesise oestrogen) -> early antral follicle -> mature follicle (only dominant follicle)

191
Q

what is ovulation and when does it occur

A

day 14

walls of follicle rupture

192
Q

what happens in the luteal phase of the menstrual cycle (day 14-28)

A

mature follicle collapses -> corpus leteum formed ->if not fertilised then aptosis -> menstuation

193
Q

what does the corpus luteum secrete

A

oestrogen
progesterone
inhibin

194
Q

what is another name for the mature follicle

A

graafian follicle

195
Q

what happens to the level of FSH during the menstrual cycle

A

increases in early follicular phase - then decreases apart from a mid cycle peak

196
Q

why is FSH required in the menstrual cycle

A

development of follicle beyond pre-antral and early antral

stimulates granulosa cells to multiply and produce oestrogen

197
Q

what happens to the level of LH throughout the menstrual cycle

A

constant for follicular phase then shows a very large mid-cycle increase

198
Q

what happens to the levels of oestrogen throughout the menstrual cycle

A

remains fairly low and stable for first week - increases rapidly during second week as dominant follicle secretes more oestrogen
then decreases before LH peak
second increase due to secretion by corpus luteum
ends with rapid decrease

199
Q

what happens to the progesterone levels during the menstrual cycle

A

small amount in follicular (by ovaries) -> corpus luteum secretes a lot after ovulation -> rapid decrease

200
Q

what happens to inhibin levels during the menstrual cycle

A

increases during late follicular -> high in luteal -> decreases as corpus luteum degenerates

201
Q

describe the menstrual phase of the menstrual cycle (uterine)

A

day 1

endometrium degenerates - stimulated by withdrawal of progesterone

202
Q

describe the proliferative phase of the menstrual cycle (uterine)

A

day 5

menstruation stops - endometrium begins to thicken + growth of myometrium via influence of oestrogen

203
Q

describe the secretary phase of the menstrual cycle (uterine)

A

soon after ovulation under influence of oestrogen and progensterone
endometrium secretes glycogen, glycoproteins and mucopolysaccharides

204
Q

what helps sperm break into the zona pellucida

A

acrosomal enzymes

205
Q

describe the stages of fertilisation

A

fertilisation-> zygote -> divides into morula -> blastocyst -> syncitrophoblast which implants into stroma

206
Q

what is the role of HcG

A

maintains corpus luteum

207
Q

how does maternal blood enter and leave the placental sinuses

A

uterine arteries and veins

208
Q

what is the role of oestrogen during pregnancy

A

stimulates growth of uterine muscle mass, regulates progesterone, prepares breasts for feeding, increases through pregnancy

209
Q

what is the role of progesterone during pregnancy

A

inhibits contractility, increases throughout pregnancy, increases thickness of uterine lining

210
Q

what is the role of relaxin during pregnancy

A

limits uterine activity and involved in cervical ripening

211
Q

what is the role of oxytocin in pregnancy

A

stimulates uterine contractions

212
Q

what is the role of prostaglandins in pregnancy

A

initiates labour

213
Q

what is parturation

A

birth process

214
Q

how much K+ is reabsorbed in the PCT

215
Q

what part of the nephron can secrete K+

A

cortical collecting ducts

216
Q

describe the phosphate urinary buffer

A

H+ excreted binds to phosphate and acid is excreted with phosphate

217
Q

describe the ammonium phosphate buffer

A

glutamate both from lumen and PCT are broken down into ammonia and carbonate
carbonate enters blood
ammonia excreted into lumen as waste

218
Q

what colour is pheomelanin

A

red/yellow

219
Q

what colour is eumelanin

A

brown/black

220
Q

what innervates the adrenal glands

A

splanchnic nerve

221
Q

what does the medulla of the adrenal glands secrete

A

catecholamines - adrenaline + noradrenaline

222
Q

what does the zona fasciculate secrete

A

glucocorticoids e.g. cortisol

SUGER (10 decks)

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