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Phase 1 Notes > SUGER > Flashcards

SUGER Flashcards

1
Q

3 categories of genetic disease

A

Mendelian genetics - single faulty gene (rare)
Complex trait genetics - multiple genes (common)
Somatic genetics - cancer

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2
Q

Summarise the human genome project

A

2001 - 90% complete
2004 - 99.7% complete
2011 - found less expected genes (21000), RNA, non-coding sequences, splicing allows more proteins to be coded for, regulatory sequences
2022 - only 5 gaps left

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3
Q

Define rare

A

1/2000 (Europe) or 1/1250 (USA)
-> 3 million in UK affected

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4
Q

What is ADPKD?
(Autosomal Dominant Polycystic Kidney Disease)

A

= Enlarged kidney with lots of holes
Disease Incidence - 1/500-1000
- Polycystin 1 + 2 genes mainly
-4th most common cause of kidney failure
-Has extrarenal manifestations e.g. intracranial aneurysms, pancreatic cysts, liver cysts etc
Treatment - vasopressin-2 receptor antagonist (ADH inhibitor)

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5
Q

What is tuberous sclerosis?

A

Develops kidney cysts, mixed tissue tumours, brain lesions, epilepsy, renal cysts, mental retardation
Very variable expressivity!
2 main genes - TSC1, TSC2
Treatment - everolimus

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6
Q

4 Functions of the kidney

A

Endocrine (secreting hormones)
Excreting waste + excess fluid
Maintain balance of salt, water, pH
Filtration + removal of drugs

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7
Q

Name the components of the kidneys

A

Cortex - glomerullus, proximal, distal convoluted tubules
Medulla - loop of Henle, collecting ducts

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8
Q

How much renal blood and urine flow per minute?

A

(Cardiac output ~ 5L/min)
Renal blood flow = 1.25L/min
Urine flow ~ 1ml/min

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9
Q

Describe arteries in kidneys

A

Renal -> Interlobar -> Arcuate -> Interlobular -> Afferent -> Glomerular -> Peritubular

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10
Q

How is juxtaglomerular specialised?

A

Contains macula dense and modified layer of afferent arteriole (increased smooth muscle , granules containing renin and acts as barometers to decreased change in bp)

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11
Q

What are the 2 mechanisms for intrinsic auto regulation of the kidneys?

A

Tubuloglomerular feedback- macula dense release prostaglandins to reduce NaCl and activate renin-angiotensin system

Moygenic mechanism - increased bp stretches vessel wall = triggers contraction and increases resistance so lowers bp. Vice versa

= Maintains GFR and excretion of water/waste

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12
Q

What are the 3 layers of glomerulus filtration barrier?

A

Capillary endothelium
Basement membrane
Foot processes of podocytes

(Fluid from blood to Bowman’s capsule to form filtrate)

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13
Q

What 5 factors determine filtration (of glomerullus)?

A
  1. Pressure (Hydostatic>osmotic)
  2. Size of molecule < 10kDa
  3. Charge of molecule (-ve harder to pass)
  4. Rate of blood flow (slow allows more)
  5. Binding to plasma proteins e.g. ca, thyroxine (protein/albumin don’t normally pass)
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14
Q

Define glomerular filtration rate

A

= Filtration volume per unit time (120ml/min)

(Kf is filtration coefficient)

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15
Q

What 3 factors is GFR determined by?

A
  1. Net filtration pressure (Back flow due to constriction of efferent increases vice Vera)
  2. Permeability of filtration barrier
  3. Surface area
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16
Q

How does sympathetic innervation affects GFR?

A

Strong sympathetic to arterioles = constrict = decrease renal blood flow = decrease GFR

Important in bleeding, shock ..

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17
Q

How is GFR measured?

A

(NOT measured directly)
Marker = filtered freely, not metabolised/absorbed/secreted

= creatinine (natural)
= Cystatin C
= Inulin infusion

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18
Q

Define renal clearance

A

All plasma that is filtered of marker
= 125ml/min (=GFR)

Clearance = urine conc x volume
——————————
Plasma conc

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19
Q

Describe the function of proximal tubules

A

Actively reabsorbs all glucose, amino acids, phosphate, HCO3

Na gradient generated by Na/K ATPase
Metabolically active - lots of mitochondria
Vulnerable to hypoxia(low O2) and toxicity(filtering toxins)

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20
Q

What is renal glycosuria disorder?

A

Sodium glucose transporters (SGLT2) is defect so glucose is not reabsorbed in proximal tubules = sugar in urine

SGLT2 inhibitor used for treating type 2 diabetes, heart failure and Chronic kidney disease

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21
Q

What are aminoacidurias disorders (e.g. cystinuria)

A

Renal basic amino acid transported (rBAT) is defect so amino acid is not reabsorbed = clumps of AA= cystine crystals and kidney stones form

Treatment
= High fluid intake - High urine flow
= Alkaline urine - increases solubility
= Chelation - binds to cystine

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22
Q

What is hypophosphataemic rickets?

A

Commonest form is XLH
Zinc dependent metalloprotease (PHEX) defect means phosphate cannot be reabsorbed = passed out

Treatment = phosphate replacement

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23
Q

Describe bicarbonate reabsorption in proximal tubules

A

H20 + CO2 form carbonic acid and splits via carbonic anhydrase to form H+ and HCO3- in tubular cells

H+ is exchanged with Na+ in tubular lumen

Na+ and HCO3- move into the blood from the tubular cells

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24
Q

What is proximal renal tubular acidosis (type 2)

A

Na/H anti Porter between tubular cell and lumen is defected = Bicarbonate is not reabsorbed

Treatment = supplementation

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25
Q

What does a defect in carbonic anhydrase affect?

A

= Mixed proximal / distal renal tubular acidoses

Inhibited by acetazolamide (mild diuretic and induces metabolic acidosis)
Also used to treat altitude sickness

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26
Q

What is the Fanconi syndrome?

A

All solutes not reabsorbed in proximal tubules may be due to Na/K ATPase failure

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27
Q

What is the function of the loop of Henle?

A

Generates medullary concentration gradient
= ascending actively reabsorb Na+ and cl- in but is impermeable to water so lumen osmolality decreases.
= Water from permeable descending limb moves into lumen
= continuous flow pushes hyperosmotic fluid to ascending limb.

Also voltage dependent ca2+ and Mg2+ absorption

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28
Q

What is Barters syndrome?

A

Defect in Na+/K+/Cl- transporters in ascending limb of loop of Henle = salt wasting

Treatment = block Na+ transporters due to Na+ overload

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29
Q

Describe the functions of distal tubule and collecting ducts

A

Fine tuning of Na+, K+ reabsorption and acid-base balance.

Collecting ducts mediates water reabsorption (principal cells) + acid secretion (intercalated cell)

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30
Q

Name some distal tubular and collecting ducts disorders

A

Gitelmans syndrome
Distal (type 1) renal tubular acidosis
Hyperaldosternosim
Type 4 renal tubular acidosis

Nephrogenic diabetes insipidus (failure of water reabsorption)
Liddle’s (More Na+, less K+ absorption due to mutation)

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31
Q

Describe different pathways for fall in bp

A

Aorta: baroreceptors increase sympathetic to increase HA and vasoconstriction

Kidney: JGA secretes renin which convert angiotensinogen to angiotensin 1->2. Causes vasoconstriction and releases aldosterone

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32
Q

Describe actions of aldosterone

A

(Steroid hormone acts on transcription)
Clings onto Na+ and exchanges it for K+ or carbonic acid
= more Na+ in blood so more water

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33
Q

What is distal (type 1) renal tubular acidosis?

A

H+ATPase or H+/K+ ATPase defect in distal/collecting ducts so failure of urinary acidification
(Due to high aldosterone)

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34
Q

What is glucocorticoid remediate aldosteronism?

A

Too much aldosterone
Treatment = ATCH suppressors stops producing aldosterone

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35
Q

What is Liddell syndrome?

A

Mutated epithelial Na+ channels so constant aldosterone effect

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36
Q

What is syndrome of apparent mineralcorticoid excess?

A

Cortisol not broken down so activates mineralcorticoid receptors

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37
Q

What is hyperkalaemic distal (type 4) renal tubular acidosis

A

Low aldosterone levels due to reduced electrochemical gradient

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38
Q

What is nephrogenic diabetes insipidus?

A

Vasopressin 2 or Aquaporin 2 channels defect so water is not reabsorbed = very dilute urine

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39
Q

Acidosis vs Alkalosis

A

Acidosis - makes blood more acidic
Alkalosis - makes blood more alkaline

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40
Q

Consequences of acidosis vs alkalosis

A

Acidosis - Hyperkalaemia, bone growth disorder, neurological, arrhythmia etc
Alkalosis - Hypokalaemia, myocardial depression, tetany etc

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41
Q

Factors affecting pH

A

CO2 conc
Intrinsic (metabolic products)
Extrinsic acid (diet, toxins)
Buffers (HCO3-)

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42
Q

Give 3 forms of the Henderson-Hasselbalch equation

A

pH = pKa + log([A-]/[HA])
pH = pKaH2CO3 + log([HCO3-]/[H2CO3])
pH = 6.1 + log([HCO3-]/0.03xpCO2)

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43
Q

Describe Stewart’s strong ion principle

A

pH and HCO3- are dependent variables governed by:
pCO2
Weak acid (ATOT) conc
Strong ion difference (SID) - Na+, K+ e.g.

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44
Q

What do we measure in ABG?

A

pH
pCO2
pO2
HCO3-
Base excess

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45
Q

What is standard bicarbonate?

A

Affected by both respiratory and metabolic so measure acid-base.

Standardised at temp 37, 5.3kPa pCO2

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46
Q

What is base excess?

A

Quantity of acid required to return pH to normal under standard conditions
(Negative in acidosis)

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47
Q

Describe metabolic acidosis

A

= Renal failure, HCO3- loss, H+ retention
= Low pH, HCO3-, CO2

Sighing respirations, tachypnoea
Hyperventilating to increase CO2 output
Long term - muscle wasting, growth retardation

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48
Q

How can we investigate acid-base disorders?

A

Anion gap = [Na+] + [K+] - [Cl-] - [HCO3-]
= difference between anions - and cations +
Normal = 10-16

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49
Q

Disorders with high anion gap

A

Renal failure
Lactic acidosis
Ketoacidosis
Acid ingestion

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50
Q

Disorders with normal anion gap

A

Diarrhoea
Renal tubular acidosis
Urinary diversion

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51
Q

Describe metabolic alkalosis

A

Causes - alkali ingestion, GI acid loss (vomiting), Renal acid loss

= Hypoventilation and renal bicarbonate excretion
= High pH, HCO3-, CO2

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52
Q

Describe respiratory acidosis

A

CO2 retention (hypoventilation, COPD) leads to increased carbonic dissociation
Causes - any respiratory failure

= Increased renal H+ excretion and HCO3- retention
= Low pH, High HCO3-, Co2

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53
Q

Describe respiratory alkalosis

A

CO2 depletion due to hyperventilation, hypoxia
Causes - type 1 respiratory failure, anxiety

= increased Renal bicarbonate loss, H+ retention
= High pH, Low HCO3-, CO2

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54
Q

Where do renal and genital systems develop from? (Embryology)

A

The intermediate mesoderm form metanephric tissue (genital) and gonad tissue (renal)

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55
Q

What are the 3 stages of kidney development?

A

(Cranial to caudal)
1. Pronephros forms and regresses at week 4 (non-functional)
2. Meseonephros- appears week 4, regresses in females but persists in males = vas deferents
3. Metanephros - week 5 (definitive kidney)

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56
Q

Describe the mesenephros stage

A

Excretory tubules develop (to bowman’s capsule) with capillaries (to glomerulus)
(Collecting duct called the mesonephric duct)
Gonad starts to develop

Females - all degenerate
Males - tubules = duct of testes
Mesonephric duct = vas deferens

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57
Q

Describe the metanephros stage

A

Definitive kidney develops in pelvic region and functions at week 12 gestation

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58
Q

What does ureteric bud develop to?

A

Grows out from the mesonephric duct and covered by cap of metanephric tissue.
Bud grows into renal pelvis -> major and minor calyx and Collecting tubules

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59
Q

What does the metanephric bud develop to?

A

Development promoted by cell clusters and renal vesicles
= forms nephrons

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60
Q

Why is the ureteric bud and metanephric tissue dependent of each other?

A

They signal each other to continue developing

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61
Q

Do foetal kidneys ascend or descend in utero?

A

Ascend

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62
Q

What is it called if kidneys don’t develop?

A

Renal a genesis
(Unilateral if one not developed or bilateral if two)
If signalling between ureteric bud and metanephric tissue fails so nephrons and collecting ducts don’t develop

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63
Q

Horseshoe vs pancake kidney

A

H - Lower poles of kidneys fuse
P - Both upper and lower poles fuse medially

Usually asymptomatic

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64
Q

Is polycystic kidney disease genetic or environmental?

A

Genetic (autosomal / recessive)

Cysts form large kidneys

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65
Q

How do polar arteries form?

A

As kidneys ascend lower vessels normally regres.

However these vessels persist = polar

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66
Q

Describe development of the bladder

A

Cloaca = common terminal cavity for urogenital system and gut

Urorectal septum tissue grows down and separates urogenital sinus and anal canal.

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67
Q

What does the urogenital sinus form?

A
  1. Upper part = bladder
  2. Pelvic part = urethra
  3. Phallic part = penile urethra in males/ vestibular vagina in females
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68
Q

Describe development of the ureter

A

Ureteric bud and mesonephric duct connect to bladder wall
(Ureteric bud forms ureter)

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69
Q

Double vs ectopic ureter anomalies

A

D - ureteric bud splits early
E - development of two ureteric bud (one enters urethra, vagina or epididymis)

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70
Q

Describe embryology of the pancreas

A

At junction of forest and midgut, 2 pancreatic ducts are generated and fuse to form a pancreas

Exocrine functions begin after birth
Endocrine functions from 10-15 weeks

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71
Q

What does the pancreas consist of?

A

Small clusters of glandular epithelial cells
98-99% = acini cells- manufacture and secrete fluid digestive enzymes in the pancreatic juice (exocrine)
2-3% = Islet cells - manufacture and release peptide hormones (endocrine)

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72
Q

Name 3 types of cells in islets of langerhans

A

Beta - secrete insulin (51 amino acids)
= glucose uptake, lipid + protein synthesis
Alpha - secret glucagon (29 aa)
= glycogenolysis, gluconeogenesis, lipolysis
Delta - secret somatostatin (inhibitor)

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73
Q

Describe insulin secretion in the Beta cells

A

GLUT2 transporters uptake varies with the glucose concentration outside.
Phosphorylated by glucokinase to glucose 6-phosphate

Rate of glycolysis is increased
ATP generated closes KATP channel, stopping efflux of K+
depolarises the membrane, opening voltage-dependent Ca2+ channels, allowing influx of calcium

This triggers insulin exocytosis from primed secretory granules

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74
Q

Describe structure of insulin

A

Pro insulin is released
Contains A chain (21) and B chain (30 amino acids) is joined by C peptide

(If C peptide not present = not made body)

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75
Q

Describe biphasic insulin release

A

B- cells sense rise in glucose and rapid release of stored products

Second phase response is slower and releases newly synthesised hormones

= Exocytosis of GLUT4 vesicles, increases glucose transporters in the cell membrane and rapid uptake of glucose

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76
Q

What is normal blood glucose levels?

A

~5mmol/mol

Short term response - glycogenesis/ glycogenolysis

Long term response - lipogenesis/ gluconeoenesis

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77
Q

Where are glucose sensors?

A

Primary - pancreatic islets

Also in medulla, hypothalamus, carotid bodies

Sensory cells in gut wall stimulate insulin increase = incretins

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78
Q

What do incretins cause and how do we turn it off?

A

Gastric delaying stimulates insulin release
DPPIV turns off incretins and prevents hypoglycaemia

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79
Q

What is diabetes?

A

A disorder characterised by hyperglycaemia
Type 1 - mutation means K+ channels don’t close so insulin isnt released
Type 2 - insensitivity to insulin

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80
Q

What is the genital ridge?

A

= ridge of mesenchyme + epithelium

(Develops from intermediate mesoderm)

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81
Q

What do primordial germ cells do (PCGs)?

A

Migrate to genital ridges in week 6 and crucial for gonads to develop + forming primitive sex cords.

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82
Q

What happens to primitive sex cords in males?

A

Continue to develop and form Sertoli cells + germ cells (to form testis cords) + leydig cells (produces testosterone at week 8)

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83
Q

What happens to primitive sex cords in females?

A

Primitive sex chord regresses and cortical cord develops instead. These divide and surround germ cells = primordial follicle

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84
Q

What is an indifferent gonad?

A

Sex is determined at fertilisation but gonad is identical in males and females until week 7.

= two pairs of ducts (mesonephric + paramesonephric)

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85
Q

What does SRY stand for?

A

Sex Coding region on Y chromosome

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86
Q

Describe male differentiation of gonads at week 7

A

Sertoli cells release Anti-mullerian hormone = paramesonephric duct regresses
SRY = testes develop
Testosterone = forms vas deferens

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87
Q

Describe female differentiation of gonads at week 7

A

Less understood
Absence of SRY, but WNT4 gene for ovarian development
Oestrogen = female differentiation and paramesonephric ducts develop

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88
Q

Describe development of mesonephric ducts in males

A

Duct opens into prostatic urethra = ejaculatory duct

Prostate develops around ejaculatory duct and seminal vesicles develop from vas deferens

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89
Q

Describe development of paramesonephric ducts in females

A

Upper parts = form uterine tubes
Caudal parts fuse = form uterus, cervix, upper vagina
Urogenital sinus = lower vagina
Growth of sinovagial bulbs = lumen develops

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90
Q

What is atresia?

A

Lower vagina doesn’t form if sinovial bulbs don’t develop

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91
Q

How does oestrogen influence female external genitalia

A

Genital tubercle = clitoris
Urethral folds = labia Minorca
Urethral groove = vestibule
Genital swelling = labia majors

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92
Q

How does testosterone influence male external genitalia

A

Genital tubercle = glans
Urethral folds = fuse to form penile urethra
Genital swellings= scrotum

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93
Q

What are produced in the testes?

A

Spermatozoa by seminiferous tubules
Testosterone by leydig cells

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94
Q

Describe the structure of the testes

A

Covered by extension of peritoneum = tunica vaginalis
White fibrous capsule = tunica albuginea
Septa divides testes into compartments containing seminiferous tubules which drain into rete testis. Leydig cells lay between tubules.
Sertoli cells promote sperm development and separate it from immune system = blood brain barrier

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95
Q

Why is scrotum outside the body?

A

Testicular thermoregulation is necessary since sperm is produced at lower than body core temperatures
(Arteriole blood cools as it descends)

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96
Q

Why does meiosis occur?

A

To keep chromosome number constant after fertilisation from generation to generation
(= 4 haploid cells prevents polyploidy)

Also increases genetic variability and chromosomal combinations

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97
Q

Type A vs type B cells in spermatogenesis

A

A - mitosis and remains outside blood-testis barrier
B - differentiate into primary spermatocytes and pass BTB to enter lumen. Meiosis 1 = secondary spermatocytes. Meiosis 2 = spermatids

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98
Q

What is spermiogenesis

A

Transforms spermatids (haploids) into spermatozoa (sprouts tail and discards cytoplasm to become lighter)

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99
Q

Difference between male and female gamete production

A

Male - mass production but not perfect process (75million in an hour)

Female - 1 egg per month per perfect

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100
Q

What is the blood testes barrier formed from?

A

Sertoli cells (if not present = infertile)

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101
Q

How long does spermatogenesis take?

A

64 days

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102
Q

Describe the hypothalamo-pituitary-testicular axis

A

Hypothalamus produces GnRH
-> Anterior pituitary gland release FSH (so Sertoli cells inhibit HP) and LSH (so leydig cells produce testosterone= inhibits)
= For spermatogenesis

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103
Q

Describe the structure of a spermatozoon

A

Head
Tail

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104
Q

Describe spermatic ducts

A

Efferent ductules
- 12 small ciliated ducts from rete teste
Epididymis
- 6m long tube site of maturation and storage on (fertile for 40-60 days)
Vas deferens
- from scrotum to bladder
Ejaculatory duct
-from vas deferens and seminal vesicles to urethra

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105
Q

Describe composition of semen

A

10% sperm
30% prostatic fluid
60% seminal vesicles fluid
(Fructose, fibrinogen e.g.)

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106
Q

Describe the menstrual cycle

A
  1. Hypothalamus- GnRH to AP
  2. Anterior Pituitary- FSH (matures follicles in ovary and thickening of uterus)
  3. Oestrogen released (thickens endometrial and causes LH release)
  4. Anterior pituitary- LH (causes ovulation at day 14)
  5. Empty follicle releases progesterone= endometrium stays thick
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107
Q

Describe fallopian tube cells

A

Keep spermatozoa alive for 5 days

108
Q

What is capacitation?

A

Spermatozoa need to stay near egg or female tract for some time before they gain the ability to fertilise the oocyte.

109
Q

Describe fertilisation

A

Proteins in Zona-pellucida (surrounds oocyte)
ZP1 attaches sperm
ZP2 reacts acrosome
ZP3 allows head to penetrate

= Through perivitelline space and binds to cortical granule (stops any more sperm entering Zona-pellucida)
= Surge of Ca2+ activates genome
= Male and female pronucleus develop and fuse to form a zygote. (Day 1)
= Mitosis + specialisation so blastocyst leaves Zona-pellucida

110
Q

Describe day 1 fertilisation

A

(Just outside ovary)
Oocyte activation triggered by sperm protein PLCz = releases Ca2+
= syngamy (pronucleus fuse)

111
Q

Describe day 2 of fertilisation

A

Moves through fallopian tubes
After 24 hours, ooplasm divide into blastomeres (cleavage)

112
Q

What is embryonic genome activation?

A

Before day 3 = mother genes do work
After day 3 = fathers genes do work

113
Q

Describe day 3 of fertilisation

A

= totipotent cells

114
Q

Describe day 4 of fertilisation

A

Cells flatten, tight junctions form, polarisation of outer cell

115
Q

Describe day 5 of fertilisation

A

= Pluripotent cells
Cavity expands and fluid fills

116
Q

Describe day 6 of fertilisation

A

Blastocyst expands and causes embryo to hatch from ZP
= implanted into uterus

117
Q

Energy requirements pre implantation vs blastocyst

A

Pre = pyruvate (simple)
B = glucose (complex)

118
Q

Describe the 3 stages of embryo implantation

A
  1. Apposition - Unstable adhesion + orientates
  2. Attachment - stronger adhesion
  3. Invasion- penetrates endothelium
119
Q

What is Human Chorionic Gonadotropin?

A

hCG sustains early preganacy by repelling immune cells of mother to protect the foetus
(Levels used to test pregnancy)

120
Q

What is the Barker Early Origins Hypothesis?

A

Small baby body size = greater risk of cardiovascular disease, 2 diabetes, stroke, hypertension
(Due to poor nutrition in womb)

Large baby body size = greater risk of cancer

121
Q

Some ethical complications of IVF

A

Multiple pregnancy risks
Increased incidence of disorders in IVF babies that wouldn’t have been able to be passed down in normal birth.

122
Q

Describe the hypothalamus-pituitary-gonad feedback loop

A

Hypothalamus release GnRH to anterior pituitary

Pituitary gland releases FSH and LH to ovaries

Ovaries release estrogen (activates cycle) and progesterone (inhibits cycle) to thicken endometrium of uterus.

123
Q

Describe meiosis in females

A

Meiosis 1:
Starts in utero before week 12 and arrests at metaphase 1
Resumes by LH surge at puberty

Meiosis 2:
Arrested at metaphase 2 until fertilisation

124
Q

Oogenesis vs spermatogenesis

A

O - in utero Meiosis 1 = polar body + primary oocyte
Meiosis 2 = polar body + secondary oocyte

S - 2 meiosis cycles in puberty = 4 spermatocytes

125
Q

What is gonadal dysgeneses?

A

Anomaly of primary sex development due to missing or extra sex chromosome

126
Q

Before vs after puberty

A

B - Low pulse amplitude of GnRH and low levels of FSH, LH and sex steroids

A - Increase amplitude and levels
(Influenced by many other factors)

Precococious puberty due to lesions, tumours, hypothyroidism etc

127
Q

What is normal body pH?

A

pH 7.35 - 7.45
[H+] 45- 35 nmol/L

128
Q

How is body pH managed?

A

Lugs mediate CO2
CO2 + H2O = H+ + HCO3-
Kidneys excrete acid and reabsorbed bicarbonate

Also diet of acids and lactate

129
Q

What is urine pH?

A

pH 4.5 (min) - 8

130
Q

What is the urinary buffer?

A

Alkaline Phosphate

131
Q

Describe movement of ammonia buffer

A

Responsive to acid load
NH3 synthesised from glutamine and diffuses into lumen at proximal tubules. Add H+ to form NH4+ and reabsorbed at loop of Henle or collecting ducts.

132
Q

Where in the kidney is Erythropoietin formed?

A

Peritibular cells in interstitial space of renal cortex
(O2 sensitive)

133
Q

Can renal compensation occur?

A

Yes - very fast, but never overcompensates
(Many renal conditions can happen at the same time)

134
Q

What is incontinence?

A

Unintentional passing of urine
(Failure to bladder store or void)

135
Q

Name 3 bladder storage incontinence problems?

A

Stress - Leak when coughing due to weak sphincter
Urge - Leak with urgency due to bladder detrusor overactivity
Mixed - both

136
Q

Name 2 bladder void incontinence problems

A

Overflow - continuous dribbling due to retention
Total - complaint of continuous leakage e.g. due to fistula

137
Q

What is needed for normal urinary tract function?

A

Storage - low pressure
(Sphincter active)
Emptying - periodic urine expulsion
(Detrusor muscle active)

138
Q

Describe neural control of lower urinary tract

A

(Young and old can’t control)
Pelvic = Bladder contraction
Hypogastric = Bladder relaxation
Pudendal = External sphincter control

139
Q

Describe bladder filling

A

Hypogastric nerve - sympathetic (NorE) on,
Pelvic nerve - parasympathetic (M2,3) off
Pudendal - voluntary sphincter on

140
Q

Describe bladder storage reflex

A

Distention produces low bladder afferent firing.
Triggers guarding reflex = sympathetic and pudendal

141
Q

Describe bladder voiding reflex

A

Intense bladder afferent firing in pelvic nerve triggers spinobulbospinal reflex = To PAG in brain.
This turns PMC on = parasympathetic outflow and inhibits sympathetic + pudendal

142
Q

Name some LUTS symptoms

A

High frequency
Nocturnal (wake up multiple time)
Urgency
Hesitancy
Slow flow

143
Q

Conservative management of incontinence

A

Weight loss
Avoid triggers: smoking, coffee
Pelvic floor muscle excercise
Containment exercise
Bladder re-training

144
Q

What % of cardiac output do kidneys receive?

A

20-25%

145
Q

Proximal vs distal tubules

A

P = bulk absorption (leaky)
D = fine tuning (impermeable)

146
Q

Describe posterior pituitary

A

Hormones vasopressin (antidiuretic) and oxytocin (labour and suckling stimulates milk ejection) Produced in hypothalamus, transported down nerve axons and stored in posterior pituitary

147
Q

Anterior vs posterior pituitary

A

A - formed from glandular tissue
P - formed from neuro tisssue (glial cells)

148
Q

Describe function of vasopressin

A

Regulates water balance:
Water ingestion decreases plasma osmolality = cells hydrated and no thirst so vasopressin decreases. Water intakes decreases and renal water increases (osmolality decreases)

149
Q

What is max urine concentration?

A

1200Osm/L

150
Q

How does vasopressin work?

A

Vasopressin bind to receptors and activate cAMP second messenger. This increases Aquaporin2 water channels into membrane = more water absorbed into the blood.

151
Q

When is vasopressin released?

A

Osmoreceptors in hypothalamus detect change in osmolality, basoreceptors detect bp change.
Increases stimulation so anterior pituitary release V1, posterior pituitary releases V2, V3.

152
Q

Vasopressin 1 vs 2 vs 3

A

1 - Vasoconstriction, platelet aggregation, glycogenolysis
2 - AQP2 channels reabsorb more water
3 - Acts on anterior pituitary to release ACTH

153
Q

What is diabetes insipidus?

A

Extreme thirst, high Na+ and high urine

= Stopped producing ADH or kidney can’t sense vasopressin
= high Na+ means more water should be reabsorbed but
= Inability to concentrate urine

154
Q

What is SIADH (Syndrome of antidiuretic hormone secretion)

A

ADH being produced when it shouldn’t be
= Concentrated urine, low osmolality, low plasma Na+, high Na+ excretion

155
Q

How many layers in the skin?

A

3:
Epidermis
Dermis
Subcutis

156
Q

What is the largest organ of the body?

A

Skin
(3.6kg, 2m squared)

157
Q

Describe functions of epidermis

A

Tight cell junctions of stratum granulosum, stratum corneal and oil layer form waterproof barrier
Vit D synthesis
Immune function
Uv protection
Thermoregulation

158
Q

Describe function of dermis

A

Thermoregulation
Vit D synthesis
Sensory organ

159
Q

Describe function of subcutis

A

Thermoregulation
Endocrine
Vit D storage
Energy reserve
Shock absorber

160
Q

Why does skin wrinkle when wet?

A

Sympathetic nervous system causes vasoconstriction in dermis to improve grip

161
Q

Why does skin wrinkle after death?

A

Washerwomen’s change due to water logging (has laid in wet for long time) so epidermis sloughs away

162
Q

How is skin a physical barrier?

A

Stratified squamous epithelium helps resist abrasive force
Fat in subcutis acts as shock absorber

163
Q

How does skin synthesise Vit D?

A

7-dehydrocholestrol present in plasma membranes of epidermal keratinocytes and fibroblasts is converted to (cholecalciferol) previtamin D3 by UV(B).
= Stored in subcutis or diffuse into bloodstream in dermis

164
Q

How is skin an endocrine organ?

A

Androgens acts on follicles and sebaceous glands (spotty)
Vit D3 synthesis
Thyroid acts on dermal fibroblasts, follicles etc (dry)
MSH increases skin pigments
Hormones in sebocytes and dermal adipocytes convert DHEA to androgens
Dermal fibroblasts form IGFBP-3

165
Q

How is skin a barrier to ultraviolet?

A

UV A is most common (B is shorter and directly damages)
Can burn, kill, photo-age collagen, DNA damage and suppress immune Langerhan cells.

166
Q

What does skin colour depend on?

A

Melanin
Carotenoids (from vegetables)
Oxy/deoxyhaemoglobin

167
Q

Describe synthesis of melanin

A

Synthesised in melanocytes from tyrosine (by melanosomes)
Transported to keratinocytes
= Photoprotective of UV
Two types:
Pheomelanin (red/yellow constant in everyone)
Eumelanin (brown/black vary)

168
Q

Do different skin colours have same conc of melanocytes?

A

Yes - same conc melanocytes, different conc melanin
(However varies in different body sites)

169
Q

How does skin respond to sunlight?

A

Immediate pigment darkening = photooxidation of melanin
Photodegredation = generates reactive oxygen species which kills cells
= increases release of melanin (delayed tanning)
= increases histamine release (vasodilation + swollen = sunburn)

170
Q

How is skin a barrier to function?

A

Granular layer keratinocytes secretes cytokines which recruite immune cells to site.
Also peptides synthesised have antimicrobial properties

171
Q

How is skin a sensory organ?

A

Merkle cells (basal epidermis) for light touch
Encapsulated mechanoreceptors in dermis - pressure, touch
Myelinated and unmyelinated sensory nerve endings - pain, itch, temperature

172
Q

How does skin regulate body temperature? (37degrees)

A

Subcutaneous fat
Cutaneous blood flow (sympathetic cholinergic = vasodilation)
1-3L per hour Eccrine sweating
Hair
Piloerection (goosebumps by sympathetic adrenergic fibres)
Metabolism
Evaporation, radiation, convection, conduction etc

173
Q

How is skin an energy store?

A

Subcutaneous fat
White adipose connective tissue

174
Q

How are sexes determined?

A

Migration of primordial germ cells from dorsal endoderm to urogenital ridge week 6-8 and development of bipotential gonad.
- Presence of SRY gene on Y chromosome = testes differentiation week 9
- Absence = ovaries week 11-12

175
Q

What affects sex differentiation?

A

Adrenal and germ cells develop from the same tissue and hormones affect sex differentiation

176
Q

Which hormone factors differentiate female week 11-12

A

WNT4
RSP01
FOXL2
(Suppresses formation of testis)
AMH (stabilises mullerian duct)
Lack of testosterone (regresses wolffian duct)

177
Q

Which hormone factors differentiate males

A

SRY + SOX9 differentiate testis
AMH (sertoli cells -> mullerian regressions week 7)
Testosterone + DHT (leydig cells release week 8)

178
Q

What does DSD stand for?

A

Disorder of Sex Develeopment

179
Q

What is the adrenal glands regulated by?

A

Hypothalamic-pituitary-adrenal axis
(CRH - ACTH - Cortisol -> Androstenedione)

180
Q

46, XX DSD vs 46, XY DSD

A

XY= Mineralocorticoid excess, sex hormone deficiency, glucocorticoid deficiency (female genitalia turn to male)
XX = opposite

181
Q

How many patients with DSD have a definitive diagnosis and why is this dangerous?

A

Only 40-50%
Carriers a risk of malignancy
(Also fertility problems, urological, sexual function, social and cultural circumstances)

182
Q

Why measure growth in children?

A

Sensitive and early indication of health with adequate nutrition and emotionally supportive environment

183
Q

Describe the infancy-childhood-puberty model

A

2-4yrs - rapid but decelerating growth determined by nutrition
4-11yrs - hormonal dependence with height velocity
11-15yrs - growth and height velocity spurt due to GH and sex hormones

Growth ends with fusion of epiphyses due to oestrogen in girls and boys (convert testosterone to oestrogen in fatty tissue)

184
Q

Name some determinants of growth

A

Parental phenotype + genotype
Quality + duration of pregnancy
Nutrition
Psycho-social environment
Growth promoting hormones + factors:
Leptin - regulates appetite
Adrenarche - maturation of adrenal gland

185
Q

All growth disorders originate from or affect the…

A

Growth plate (chondrogenesis)

186
Q

Regulators of growth

A

Nutrition
Extracellular fluids
Inflammatory cytokines
Endocrine signals

187
Q

Regulation of growth hormone secretion

A

GHRH: Growth Hormone Releasing Hormone (regulated by food, sleep, steroids)
SST: Somatostatin
Released from hypothalamus affects release of GH from anterior pituitary
-> Liver releases IGF-1
-> Opposite to insulin effect on growth plate and cortical bone

All a negative feedback loop

188
Q

Where is GH synthesised?

A

40-50% anterior pituitary synthesised by somatroph cells
(Most abundant hormone)
Pulsation secretion max at night

189
Q

Influences on GH secretion

A

Stimulation: Exercise, stress, fasting, high protein meals, puberty, hypoglycaemia

Suppression: hypothyroidism, aging, high carbohydrate meals

190
Q

Definitive signs of puberty

A

(Don’t significantly fertility)
Girls - Menarche (first period)
Boys - first ejaculation

191
Q

Describe development of secondary sexual characteristics

A

Girls:
Oestrogen and androgens develop breasts, pubic hair and genitalia

Boys:
Testicular androgens develop genitalia, pubic hair, voice deepening

192
Q

Precocious vs delayed puberty

A

Precocious- onset of secondary sexual characteristics before 8(girls), 9(boys)
= risk of brain tumour
Delayed - absence by 14(girls), 16(boys) may lead to reduced peak bone mass and osteoporosis

193
Q

What is the hypothesis for puberty start?

A

Increased stimulatory glutamate and kisspeptin
Decreased inhibitory GABA and opioids
->Increase in hypothalamic GnRH

194
Q

Primary vs secondary/tertiary hypogonadism

A

Primary (gonads) - Hypergonadotrophic hypogonadism (too much GnRH)

Secondary/ tertiary (pituitary/hypothalamus) - hypogonadotrophic hypogonadism (not enough GnRH)

195
Q

Describe a healthy skin barrier

A

Cells full of natural moisturising factor containing acids.
Filaggrin breaks this down to keep surface at a low pH 5.
Protease inhibitors and low pH stop degratory proteases from breaking down corneodesmosomes (holds skin cells together)
Low pH enhances lipid processing enzymes
= Irritants bounce off skin and water is retained

196
Q

Why are babies more at risk of developing atopic dermatitis?

A

Have a thinner skin barrier (layer)
-> Also why face is mostly affected

197
Q

What happens in genetic predisposition to atopic dermatitis

A

Mutation means no filaggrin breakdown NWMF so surface pH increases.
This reduces lipid processing enzymes and degradatory proteases break down corneodesmosomes

198
Q

How do skin and detergents break down skin barrier?

A

Raise surface pH

199
Q

How does atopic dermatitis progress

A

Genetic predisposition - Environmental triggers - Allows irritants through skin

200
Q

Describe some environmental triggers for atopic dermatitis

A

Raises pH:
Saliva, breast milk
Bed bug faeces
Food penetration through skin

201
Q

Can inflammation of skin causes depression?

A

Yes

202
Q

Define hormones

A

Substance secreted directly into the blood by specialised cells to bind specific receptors and influence cellular reactions

203
Q

Name some endocrine glands

A

Hypothalamus
Pituitary
Thyroid
Parathyroid
Adrenal
Pancreas
Ovary / Testes

204
Q

Name other endocrine organs

A

Heart
Liver
Skin (fat)
Kidney
Intestines

205
Q

What are hormones synthesised from?

A

Steroid - cholesterol
Peptides - Amino acids (tyrosine)
Thyroid - tyrosine in thyroglobulin forms thyroxine (T4)

206
Q

Which hormones bind to surface vs Intracellular receptors?

A

Surface - peptide
Intracellular - steroid, thyroid
(Deiodinases form T3 from T4)

207
Q

How to measure hormones?

A

Bioassays
Immunoassays
Mass spectrometry

208
Q

What are the anterior pituitary hormones?

A

Glycoproteins:
TSH - thyroid hormone synthesis
LH - ovulation
FSH - egg/ sperm development
Polypeptides:
Prolactin- breast milk production
GH - growth
ACTH - regulation of adrenal

209
Q

What are posterior pituitary hormones?

A

ADH - Water regulation
Oxytocin - breast milk expression

210
Q

Describe blood supply to anterior pituitary

A

Hormones released into portal venous circulation from hypothalamus
(No arterial supply)

211
Q

Function of hypothalamus

A

Homeostasis + primitive functions e.g. appetite, thirst, sleep, Temperature
Controls endocrine via pituitary

212
Q

Hypothalamus hormones

A

Thryotropin (TRH) - TSH
Corticotropin (CRH) - ACTH
Gonadotropin releasing hormone - LH/FSH
GH releasing hormone (GHRH) - GH
Somatostatin - inhibits GH
Dopamine - inhibits prolactin

213
Q

Effect of ACTH

A

(Stress, cytokines, diurnal (when awake) -> CRH -> ACTH)
Causes adrenal glands to release cortisol
(negative feedback on CRH and ACTH)

214
Q

Effect of growth hormone

A

Pulsation released through life
Stimulated by low glucose, sleep, exercise
= Protein synthesis, lipolysis, glycolysis, cartilage growth

215
Q

Effect of thyroid stimulating hormone

A

Controls how much energy the body uses

216
Q

Effect of LH and FSH in females

A

LH stimulates ovulation
FSH stimulates development of follicles (during ovulation)

217
Q

Effect of prolactin

A

Synthesised by lactotrophs
Inhibited by tonic release of dopamine

Essential for lactation and suppresses GnRH therefore decreased LH/FSH

218
Q

Pituitary tumours cause:

A

Pressure on local structures
E.g. optic chasm = bitemporal hemianopia
Pressure on pituitary - hypopituitarism
Functioning tumour e.g. Cushing
Chronically nerve damage etc

219
Q

Describe some pituitary diseases

A

Hyperprolactinaemia - due to tumours, less dopamine
Benign pituitary adenoma
Craniopharyngioma - benign tumour

220
Q

Excess pituitary hormones lead to:

A

ACTH - increased cortisol (Cushing’s disease)
GH - Acromegaly
LH/FSH - misgivings stop periods
TSH - thyrotoxicosis
Prolactin - galactorrheoea, prolactinomas

221
Q

Deficiency of pituitary hormones (hypopituitarism) lead to:

A

GH - reduced linear growth
LH/FSH - hypogonadism
ACTH - adrenal insufficiency
TSH - hypothyroidism

222
Q

Adrenal medulla vs cortex synthesis

A

Cortex - Effect of ACTH =
(Zona glomerulosa) mineralocorticoids - aldosterone
(Zona fasiculata)
Glucocorticoid - cortisol
(Zona reticularis)
adrenal androgens - DHEA

Medulla- Catecholamines

223
Q

Describe cortisol structure

A

Cholesterol precursor
3 cyclohexane rings
1 cyclopentane ring

224
Q

Classification of steroids

A

21 carbons = progesterone, corticoid
19 carbons = androgens
18 carbons = oestrogen

225
Q

Glucocorticoid function

A

Permissive function so that other hormones can work
Important in homeostasis and stress
- increase glucose mobilisation
- Maintenance of circulation
- Dampens immune response
(Act on most tissue)

226
Q

Transport of glucocorticoids

A

90% bound to CBG
5% bound to albumin
5% free - only one available

During inflammation, CBG decreases so more % free cortisol available

227
Q

Define stress

A

Sum of the body’s response to adverse stimuli
E.g. infection, trauma, haemorrhage, exercise, medical illness

228
Q

Describe effect of aldosterone

A

In collecting ducts, diffuse into cells and acts on nucleus to transcript Na+K+ATPase. So more Na+ and water is reabsorbed

229
Q

Is endocrine salt loss primary or secondary adrenal insufficiency?

A

Primary = low Na+, high K+ in plasma

230
Q

Describe adrenal androgens

A

Weak generated by adrenal gland.
Precursor of oestrogen and regulated by ACTH
DHEA most abundant

231
Q

Adrenal medulla function

A

Specialised ganglia supplied by sympathetic preganglia synthesises noradrenaline

Synthesises adrenaline from noradrenaline when high cortisol

catecholamines = 80% adrenaline, 20% noradrenaline

232
Q

Thyroid anatomy

A

Brownish-red in neck. Right and left lobes united by a narrow isthmus surrounded by a thin fibrous capsule of connective tissue

233
Q

How may ectopic thyroid tissue, cysts and pyramidal lobes form?

A

If descent during embryology leaves behind tissue

234
Q

Describe thyroid gland cells

A

Thyroid epithelial/ follicles produces hormones and surround colloid. Supporting c cells nearby all covered by basement membrane.

235
Q

Function of thyroid hormones?

A

Control of metabolism: energy generation and use
Regulation of growth
Development

236
Q

T3, T3 and TSH levels in hypothyroidism vs hyperthyroidism

A

Hypo: T3, T4 low, TSH high
(Underactivity)
Hyper: T3, T4 high, TSH low
(Overactivity)
Goitre = enlargement

237
Q

Describe thyroid hormone synthesis

A
  1. TSH binds to TSHR on basement membrane
  2. Iodine- is uptake by NIS symporter
  3. Iodisation of tyrosine residues and coupling by thyroperoxidase
  4. Export of mature Tg to colloid where it is stored

(Tyrosine -> diiodotyrosine -> thyroxine)

238
Q

T3 vs T4

A

Triiodothyronine = 3 iodines vs thyroxine = 4
(T3 is more biologically active by mono-deiodoination of T4)

239
Q

How does thyroid hormone act?

A

Travels through transmembrane transporter to cell nucleus where transcription is induced = affects metabolism

240
Q

Symptoms of hypo vs hyperthyroidism

A

Hyper:
Tachycardia, AF, shortness of breath, weight loss, tremor, myopathy, anxiety, double vision
Hypo:
Bradycardia, heart failure, weight gain, constipation, depression, carpal tunnel syndrome

241
Q

Function of parathyroid glands

A

Regulates calcium and phosphate levels by secreting parathyroid hormone when low calcium or high phosphate.
= Increases Ca reabsorption in distal tubules, in intestine
= Increase calcium release from bone to soluble calcium
= Decrease phosphate reabsorption

C cells release calcitonin to raise calcium levels
(Vit D important)

242
Q

What % of serum calcium is free?

A

50% of serum calcium is free
50% bound to albumin

243
Q

Describe parathyroid hormone structure

A

84 amino acids cleaved to smaller peptides and assayed by two site assays. Binds to G protein coupled receptors in kidneys (production of active Vit D, reabsorption of calcium) and osteoblasts.
Also enhances osteoclasts for bone resorption
Normal adult referent = 1.6-6.9 pool/L

244
Q

Different hyperthyroidism

A

= raised serum PTH
Primary - parathyroid tumour
Secondary - pituitary disease may cause renal disease
Tertiary - hypothalamus disease causes irreversible hyperplasia

245
Q

Describe calcitonin

A

Produced by thyroid c-cells and released in hypercalcaemia. Not essential to life.
2 calcitonin genes products from a single gene and primary RNA transcription

246
Q

Define ovary

A

1/2 female reproductive glands that contain ova or eggs that are released during ovulation

247
Q

What scan is best for looking at reproductive organs?

A

Ultrasound
= sound waves bounce off fluids and tissues and recorded by transducers
= no ionising radiation
= helps guide needles

248
Q

Why is a transvaginal ultrasound used?

A

With large obese patients, most waves deflected.
Allows view of endometrium lining, thickness, ovaries and myometrium

249
Q

When would you do an ultrasound during pregnancy?

A

12 weeks = dating, heart beat and unchallenged thickness
20 week = anomaly scan
Additional if clinical problems

250
Q

What may foetal maternal referral

A

Diagnosis

251
Q

Define menopause

A

Cessation of menstruation

252
Q

What is climacteric (perimenopause)

A

Period around menopause and at least the first year after it

253
Q

Define post-menopause

A

12 months of no period

254
Q

Average age of menopause?

A

51
(48-52)

255
Q

Cause of menopause

A

= Depletion of primordial follicles in ovary
Decline of oestrogen production (fluctuates then gradual decline and affects other organs)
Gradual rise of FSH and LH (lack of negative feedback)
Age of menopause decided by size of primordial pool

256
Q

Causes of premature menopause

A

Idiopathic
Iatrogenic e.g. Surgery, chemo
Chromosomal
Autoimmune

257
Q

How are primordial follicles lost?

A

Atresia

258
Q

How long does it take for primordial follicles to mature and ovulate?

A

2.5 months

259
Q

Premature menopause increases risk of

A

Mortality
Heart disease
Cognitive dysfunction
Bone mineral density
Autoimmune and thyroid disease

260
Q

Tests to confirm (pre-) menopause

A

Antral follicle test
Anti-mullerian hormone test
Stromatolites velocity

261
Q

Menopause symptoms

A

4-12 years!
Vasomotor - hot flush, sweat, palpitation, headaches
Physiological - irritability, low mood, lethargy, emotional
Urogenital - vaginal dryness, urethral syndrome
Skin - dryness, brittle nails
Osteoporosis - bone remodelling is uncoupled
Cardiovascular disease - angina, myocardial infarction, cerebrovascular stroke

262
Q

Treatment for menopause

A

Hormone replacement of oestrogen (+ progesterone reduce endometrial cancer)
Beta blockers
Sedatives
Clonidine
Lifestyle advice
Supplements e.g. calcium
Monitoring
Local steroids
Complementary therapies

263
Q

Types of hormone replacement therapy

A

Oral
Skin patches
Signal cream
Skin cream
Nasal spray
Vaginal ring

264
Q

Long term risks of hormone replacement therapy

A

Cardiovascular
Breast cancer (progesterone)
Cancer (oestrogen)
Venous thromboembolism

265
Q

Contraindications of HRT

A

Abnormal liver function
Thromboembolic disease
Conginetsli lipid metabolism
Hormone dependent tumours
Sickle cell aenemia

Phase 1 Notes (9 decks)

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