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Flashcards in Human Physiology Deck (216):
1

What is an antidiuretic?

Stops you weeing

2

What is vasopressin?

Antidiuretic hormone which makes the tubular wall more permeable to water for greater water reabsorption

3

Where is vasopressin made and stored?

It is made in the hypothalamus and stored in the posterior pituitary gland

4

What is a diuretic?

Makes you wee

5

What is plasma clearance?

Volume of plasma completely cleared of a substance by the kidneys per minute (ml/min)

6

What is the equation for plasma clearance?

Plasma clearance (ml/min) = urine conc per ml x urine flow (ml/min)/plasma conc per ml

7

When does plasma clearance = gfr

When the substance is freely filtered and not reabsorbed e.g. Creatine and insulin

8

What substance is used to estimate gfr?

Creatine since it is freely filtered and not reabsorbed

9

What is not filtered out by the glomerulus?

Plasma proteins

10

What 3 layers does a substance pass through to be filtered by the glomerulus?

Glomerular capillary wall
Basement membrane (acellular)
Inner layer of the bowman's capsule

11

What is the name of an arteriole leading to somewhere?

Afferent arteriole

12

What is the name of an arteriole leading away from somewhere?

Efferent arteriole

13

What forces are involved in glomerular filtration?

Glomerular capillary blood presure

Plasma colloid osmotic pressure

Bowman's capsule hydrostatic pressure

14

What is net filtration pressure?

Forces favouring filtration - forces opposing filtration

15

What is GFR?

Glomerular filtration rate. Amount of fluid filtered through the glomerulus per min. Ml/min. Usually 125ml/min

16

What is GFR usually?

125ml/min

17

What does GFR depend on?

Net filtration

Glomerular surface area

Glomerular permeability

18

What is the equation for GFR?

GFR = net filtration x glomerular surface area

19

How are changes in blood pressure regulated in the glomerulus?

Increase BP = afferent arteriole vasoconstriction (less blood to glomerulus)

Decrease BP = afferent arteriole vasodilation (more blood to glomerulus)

20

What is filtered load?

Amount of a substance filtered from the glomerulus per minute (mg/min)

21

What is Tm?

Max amount of a substance that can be reabsorbed by the tubule per minute. Mg/min.

22

What is the equation for filtered load?

Plasma conc x gfr

23

What is Tm limited by?

The number of carriers present in the tubule membrane

24

Equation for excretion of a substance?

Filtered load - Tm

25

What is an exocrine gland?

Secretes a substance onto epithelia via a duct

26

What is an endocrine gland?

Secretes hormone into the blood (no duct)

27

What are 7 functions of the kidney?

Excretion of metabolic waste products and foreign chemicals

Regulation of water and electrolyte levels

Regulation of acid/base levels

Regulation of arterial blood pressure

Regulation of rbc production

Secretion, metabolism and excretion of hormones (epo)

Gluconeogenesis

28

Which blood vessels supply nephrons?

Arcuate arteries

29

Which blood vessel supplies the glomerulus?

Afferent arteriole

30

What does the efferent arteriole in a nephron do?

Carries blood from the glomerulus to the peritubular capillaries

31

What are the 2 capillary beds in a nephron?

The glomerulus and the peritubular capillaries

32

Where are the peritubular capillaries found?

Around the loop of henle

33

How many nephrons in a kidney?

800,000 - 1,000,000

34

Can nephrons be regenerated?

No

35

What are the 5 barriers that must be crossed in reabsorption?

Luminal cell membrane
Cytosol
Basolateral cell membrane
Intersitial fluid
Capillary wall

36

What % of Na reabsorption takes place in the proximal tubule?

67%

37

What percentage of Na reabsorption takes place in the loop of henle?

25%

38

What percentage of Na reabsorption takes place in the distal and collecting tubules?

8%

39

Which substance promotes Na reabsorption?

Aldosterone

40

Which substances inhibit Na reabsorption?

Atrial natriuretic peptide
Brain natriuretic peptide

41

What secretes aldosterone?

Adrenal cortex

42

What secretes renin?

Kidney

43

Which enzyme cleaves angiotensin 1 (10 aa) to angiotensin 2 (8aa)?

ACE

44

Where are natriuertic peptides stored?

Granules in the atria and ventricles

45

Do endocrine glands have ducts?

No

46

What are the 2 hormone groups?

Hydrophilic (peptides and catecholamines)

Lipophilic (steroid hormones and thyroid hormones)

47

What are the 7 major endocrine glands?

Hypothalamus
Pituitary gland
Thyroid
Parathyroid
Adrenal gland
Pancreas
Ovaries/testes

48

Which type of hormone can cross cell membranes?

Lipophilic hormones (steroids and thyroid hormones)

49

Which hormones have extracellular receptors?

Hydrophilic hormones (peptides and catecholamines)

50

What 5 things does aldosterone do?

Increases sodium potassium atpase channels on basolateral membrane

Increases sodium/chloride symporters on apical membrane

Increases Enac channels on apical membrane

Increases Enac activity by activating protein kinases

Increases Enac activity by activating prostatin which cleaves Enac precursors

51

How do steroid hormones travel in the blood?

Attached to carrier proteins

52

Which type of hormone is stored?

Peptide hormones

53

Which type of hormone is made on demand?

Steroid

54

Which type of hormone is broken down faster?

Peptide

55

What is the half life of peptide hormones?

Minutes

56

What is the half life of steroid hormones?

Hours

57

How long do the effects of peptide hormones last?

Minutes to hours

58

How long do the effects of steroid hormones last?

Hours to days

59

What connects the hypothalamus and the pituitary gland?

Infundibulum

60

What is permissiveness in terms of hormone control?

Where presence of one hormone is needed for another hormone to exert its full effect on target cells

61

Give an example of permissiveness

Thyroid hormone increases the effect of adrenaline on the liver and heart

62

What is synergism in terms of hormone control?

Several hormones combine to produce an effect greater than the sum of all their individual effects

63

Give an example of synergism?

Testosterone requires FSH for normal sperm production

64

What is antagonism in terms of hormones?

One hormone reduces the effect of another

65

Give an example of hormone antagonism

In pregnancy progesterone inhibits the effects of oestrogen on the uterus

66

Primary hypersecretion

Gland produces xs hormone

67

Give an example of primary hypersecretion

Cushings disease. Adrenal gland produces xs cortisol

68

Secondary hypersecretion

Too much tropic hormone

69

Primary hyposecretion

Gland secretes too little hormone due to non functioning gland or dietary deficiency

70

Give an example of primary hyposecretion due to a non functioning gland

Addisons disease - adrenal gland does not produce enough cortisol

71

Give an example of primary hyposecretion due to dietary deficiency

Shortage of thyroid hormone due to shortage of iodine in the diet

72

Secondary hyposecretion

Low secretion of a hormone due to low production of tropic hormone

73

Tertiary hyposecretion

Low secretion of hormone and tropic hormone due to low secretion of hypothalamus hormone

74

What connects the hypothalamus and the posterior pituitary gland?

Hypothalamo-hypophysial nerve tract

75

What are the 2 posterior pituitary gland hormones?

Oxytocin and vasopressin

76

Describe the structure of oxytocin and vasopressin?

9 amino acids
Disulfide bond between 1 and 6 forming a ring

77

What type of receptors do oxytocin and vasopressin bind to?

G protein linked cell surface receptors

78

What transport protein is used to transport hormones from the hypothalamus to the posterior pituitary gland?

Neurophysin

79

Where are granules stored in the posterior pituitary gland?

Hering bodies

80

How are granules released from the posterior pituitary gland?

Calcium dependent exocyotosis

81

What second messenger system is associated with oxytocin?

IP3

82

What is the name for over production of vasopressin?

SIADH

83

What is the treatment for over production of vasopressin?

Vasopressin antagonist such as demeclocycline

84

What does vasopressin under production lead to?

Diabetes insipidus

85

What is the treatment for diabetes insipidus?

Synthetic vasopressin

86

What 3 effects does vasopressin have?

Increase cortisol
Increase water retention (aqp)
Increase blood pressure by vasoconstriction

87

What receptors are associated with vasopressin?

V1a = smooth muscle
V1b = corticotrophs
V2 = kidney

88

What second messenger system is associated with vasopressin?

V1 - IP3
V2 - cAMP

89

Where is testosterone produced in women?

In the ovaries and adrenal glands

90

Where is testosterone produced in women?

In the ovaries and adrenal glands

91

How do men produce estrogen?

Aromatase converts testosterone to estradiol

92

What is acromegaly?

Excess growth hormone is produced after epiphyseal fusion

93

What is a feature of acromegaly?

Face coarsening. Bones cannot grow anymore due to epiphyseal fusion but tissues can still grow

94

What are 2 common cause of anterior pituitary hormone primary hypersecretion?

Pituitary adenoma and lack of suppression of hypothalamic trophic hormone

95

How does cushings disease lead to diabetes?

Increased cortisol means increased gluconeogenesis which can lead to insulin resistance and type 2 diabetes

96

Which thyroid hormone has a longer half life?

T4 (5 - 7 days as opposed to 1 - 3 days)

97

Which thyroid hormone is more abundent?

T4 (98%)

98

Where are thyroid hormone receptors found?

In the nucleus of target cells

99

How do men produce estrogen?

Aromatase converts testosterone to estradiol

100

What is acromegaly?

Excess growth hormone is produced after epiphyseal fusion

101

What is a feature of acromegaly?

Face coarsening. Bones cannot grow anymore due to epiphyseal fusion but tissues can still grow

102

What is a common cause of anterior pituitary hormone primary hypersecretion?

Pituitary adenoma

103

How does cushings disease lead to diabetes?

Increased cortisol means increased gluconeogenesis which can lead to insulin resistance and type 2 diabetes

104

On which part of the nephron does vasopressin act?

Distal tubule

105

What are the 3 types of sex hormones?

Oestrogens
Progesterones
Androgens

106

What are the 3 steps of spermatogenesis?

Mitosis
Meiosis
Cytodifferentiation

107

What are the 5 stages of the human life cycle?

Embryonic/foetal development
Infancy and childhood
Puberty and adolescence
Adulthood
Late adulthood/old age

108

What hormone changes are associated with menopause?

Increased FSH and LH levels. Decreased levels of progesterone and oestrogen due to decline in ovarian reserve

109

What are gonadotrophins?

FSH and LH

110

What are the symptoms of menopause?

Vasomotor
Psychological
Urogenital
Bone loss

111

What are the side effects of oestrogen hrt?

Breast tenderness
Bloating
Nausea
Headaches

112

What are the side the side effects of progesterone hrt?

Depression, mood swings
Skin changes
Abnormal bleeding

113

What are the risks of hrt?

Increased risk of breast and ovarian cancer

114

How does the COC pill work?

It blocks ovulation

Thickens cervical mucus

Creates a hostile endometrium which decreases the possibility of implantation should fertilisation occur

115

How does the progesterone only pill work?

Thickens cervical mucus

Creates a hostile endometrium so implantation cannot occur even if fertilisation takes place

116

Where is the site of fertilisation?

Ampulla of the oviduct

117

When does fertilisation usually occur?

24 hours after ovulation

118

How long can sperm survive?

48 hours usually but can survive up to 5 days in the female reproductive tract

119

Trace the journey of sperm through the female reproductive tract

Vagina, cervical canal, uterus, oviduct, ampulla

120

How does the female reproductive tract aid sperm migration?

Myometrium contractions

Upward contractions of the oviduct smooth muscle

Mature egg releases the chemoattractant allurin

121

Where does capacitation occur?

Female reproductive tract

122

What is capacitation?

Final maturation step that sperm undergo which allows them to penetrate and fertilise an egg

123

What occurs during capacitation?

Cholesterol is withdrawn from the membrane

Proteins are redistributed

Calcium enters the cell

124

Which two layers must a sperm penetrate to fertilise an egg?

Granulosa cells

Zona pellucida

125

How do sperm cells break through granulosa cells and the zona pellucida?

Acrosomal reaction

126

How long after fertilisation does a blastocyst move into the uterus?

3 days

127

How long after fertilisation does a blastocyst implant?

7 days

128

What are the 5 functions of the placenta?

Protection (from mother's immune system)

Nutrition

Excretion

Gas exchange

Hormone secretion (placenta is an endocrine gland)

129

When does the placenta start to form?

Day 7

130

When must the placenta be completely self sufficient by?

Week 12

131

How long does the corpus luteum survive in pregnancy?

Around 10 weeks

132

Describe the signalling pathway used in liver regeneration?

Hippo pathway. Yap stays in the cytoplasm if a cell has neighbours, yap moves to the nucleus if a cell does not have neighbours

133

What is the name of macrophages in the liver?

Kupffer cells

134

What is the main haematopoietic organ up until 5 months of gestation?

Liver

135

Mammogenesis

Development of mammary glands

136

When does Mammogenesis occur?

Pregnancy

137

Lactogenesis

Development of lactation

138

Galactopoiesis?

Maintenance of lactation

139

Explain the contraceptive effect of breastfeeding

Prolactin inhibits GnRH secretion by the hypothalamus, resulting in amenorrhoea

140

How does dopamine affect breast feeding?

It inhibits prolactin so stops lactation

141

What are the advantages of breast feeding?

Less chance of breast cancer (especially triple negative, hard to treat breast cancer), immune transfer to baby, uterus returns to normal size quicker (oxytocin released by suckling)

142

What stimulates milk production?

Drop in oestrogen, progesterone, prolactin and hCS at birth. Suckling is required to stop prolactin levels dropping further and lactation stopping. At weaning when suckling stops prolactin levels drop and lactation stops.

143

What is breast milk made up of?

90% water
7% lactose

144

How many calories in 100ml of breast milk?

70 kcal

145

What pH is breast milk?

7

146

What are the 3 stages of breast milk?

Colostrum
Transitional milk
Mature milk

147

What is involution?

When the breasts stop producing milk after weaning

148

What are the differences between colostrum and mature milk?

Colostrum has less lactose and fat but has more IgG, protein, minerals and fat soluble vitamins

149

What is priapism?

Persistant painful erection

150

What are the main causes of erectile dysfunction?

Vascular disease (diabetes mellitus)

Neurogenic

Hormonal

Pharmacological

Psychological

151

How does viagra work?

It is a PDE-5 inhibitor which inhibits breakdown of cGMP. More cGMP = more smooth muscle relaxation in trabeculae = erection

152

What are the 3 layers of the adrenal cortex and what do they each produce? (From outermost to innermost layer)

The zona glomerulosa produces aldosterone

The zona fasciculata produces cortisol

The zona reticularis produces sex steroids

153

What cells are found in the adrenal medulla?

Adrenal chromaffin cells

154

What do adrenal chromaffin cells secrete?

Catecholamines

155

What are catecholamines?

Adrenaline
Noradrenaline
Dopamine
ATP

156

What is pheochromocytoma?

Tumour of adrenal chromaffin cells which secretes high amounts of catecholamines

157

What is an advantage of the POP over the COCP?

POP has no oestrogen (oestrogen promotes thrombosis) so POP does not increase risk of DVT.

158

Who is not permitted to use the COCP and why?

Women with sickle cell disease. Sickle haemoglobin polymerises when deoxygenated.

159

How do the POP and the COCP stop ovulation?

Inhibit FSH and LH secretion by the hypothalamus

160

What are the symptoms of PCOS?

Obesity
Androgenic features
Amenorrhagia (no ovulation)

161

What is the mechanism of PCOS?

High LH and insulin levels work synergistically to increase ovarian growth and androgen production

162

Which type of immunoglobulin is found mainly in breast milk and why?

IgA for protection against enteric infection

163

Why does cushings syndrome cause increased androgen levels?

Because cushings syndrome is a defect of the adrenal cortex where androgens are made

164

Which two cell types are found in the distal and collecting tubules?

Intercalated cells (acid base balance)

Principal cells (aldosterone and vasopressin)

165

What things do natriuretic peptides do to inhibit Na+ reabsorption?

Inhibit aldosterone secretion from adrenal cortex
Inhibit secretion and action of vasopressin
Inhibit renin secretion by kidney
Increase GFR by increasing BP in glomerulus by afferent arteriole vasodilation and efferent arteriole vasoconstriction

166

What is the result of natriuretic peptide secretion?

Increased Na+ and accompanying osmotic water excretion from the urine

167

Which natriuretic peptide is more effective?

ANP

168

What is the name of the sodium glucose cotransporter?

SGLT

169

What is a symporter?

Uses the movement of one substance with its conc gradient to transport another substance against its conc gradient across a membrane. Both substances are moving in the same direction.

170

What is an antiporter?

Uses the movement of one substance with its conc gradient to transport another substance against its conc gradient across a membrane. The substances are moving in opposite directions

171

What is the name of the glucose transporter on the basolateral membrane of tubule cells which transports glucose with its conc gradient?

GLUT

172

What are the 2 types of aquaporins and how are they different?

Aqp 1 is found in the proximal tubule and is always open

Aqp 2 is found in the distal tubule and is under the control of vasopressin

173

What is the role of probenecid?

It allows penicillin to stay in the body longer

174

What are acid sources?

Lactic acid
Ketoacids (diabetes mellitus)
CO2

175

How is pH homeostasis maintained?

Ventilation
Buffers
Kidneys

176

Where are aquaporins 2 stored in principal cells?

Vesicles

177

What is nocturnal enuresis?

Bed wetting due to reduced vasopressin secretion at night

178

What is pharmacodynamics?

What the drug does to the body

179

What is pharmacokinetics?

What the body does to the drug

180

What is the difference between agonists and antagonists?

Agonists activate receptors
Antagonists block receptors

181

Biased agonism

Different ligands bind to the same receptor and cause activation of different pathways

182

Ec50

Dose which gives response at 50% of maximum

183

What is osmotic diuresis?

Increase in urination rate

184

What is bioavailability?

The proportion of a drug that enters circulation

185

What type of diuretic would you use to treat hypertension and why?

Thiozide. It blocks Na/Cl channels on the apical membrane of epithelial cells in the distal tubule

186

Which type of diuretic would you use to treat liver disease and why?

Potassium sparing diuretic because they block Na/K exchange in the collecting tubule

187

Which type of diuretic would you use to treat water retention?

Loop diuretic

188

Which type of diuretic would you use to treat kidney disease?

Potassium sparing or loop

189

Which type of diuretic would you use to treat heart failure?

Potassium sparing or loop

190

Name the 5 types of diuertic and say where they act

Osmotic (PCT)
Loop (ascending loop of henle)
Carbonic anhydrase inhibiting
Thiazide (DCT)
Potassium sparing (collecting tubule)

191

Which type of diuretic would you use to treat cerebral oedema or glaucoma?

Osmotic (mannitol)

192

Name a loop diuretic

Furosemide

193

Name a thiozide

Bendroflumethiozide

194

Name a potassium sparing diuretic?

Amiloride

195

Which diuretics are sulfonamides?

Loop diuretics
Thiozides

196

Which diuretic is the only one which reduces renal blood flow?

Thiozide

197

Which diuretic has the longest half life?

Amiloride (6 - 9 hours)

198

Which diuretics are associated with gout?

Mainly thiazide but also loop

199

How is mannitol administered?

IV

200

Which diuretic has the shortest half life?

Furosemide (less than 100 mins)

201

What is the half life of a drug?

The amount of time for the concentration of a drug in the body to be reduced to half the original value

202

What is desmopressin?

Synthetic vasopressin

203

How is furosemide administered?

Oral
IV
IM

204

How is bendroflumethiozide administered?

Oral

205

How is amiloride administered?

Oral

206

What are the 4 processes associated with pharmacokinetics

Adme
Absorption
Distribution
Metabolism
Excretion

207

What is MTC in terms of pharmacokinetics?

Maximum tolerated concentration

208

What is MEC in terms of pharmacokinetics?

Minimum effective concentration

209

What does intrathecal mean?

Into the spinal cord

210

What are the 4 main body fluid compartments?

Plasma
Interstitial fluid
Transcellular fluid
Intracellular fluid

211

Which type of molecules can pass through the blood brain barrier?

Lipophilic

212

Why would you administer a drug intrathecally?

Because it can bypass the blood brain barrier

213

Volume of distribution

Volume into which the drug appears to be distributed with a concentration equal to that in the plasma

214

Why is relatively little lipophilic drug found in the plasma?

A lot gets sequestered in adipose tissue

215

What is the main site of drug metabolism and the site of first pass metabolism?

Liver

216

Damage to which part of the spinal cord causes back pain?

Sciatic nerve