Phys/Anat facts Flashcards
Where is EPO produced in the neonate
The liver is the predominant site of erythropoietin secretion in the fetus. In adults and children, the kidney is the main site.
What nutrients are absorbed in the duodenum
Ions! calcium, magnesium, phosphate
+ iron, folic acid.
What nutrients are absorbed in the proximal 100-200cm of small intestine:
CHO, protein, water-soluble vitamins
What nutrients are absorbed throughout small intestine
monoglycerides and fatty acids as micellar complexes; medium chain TG directly into the portal circulation.
What nutrients are absorbed in the distal ileum
B12, bile acids, Ca2+
How is Ca2+ absorbed through the gut?
- Duodenum and upper jejunum: active vitamin D-dependent transport (more efficient, less Ca
- Ileum: passive vitamin D-independent, paracellular diffusion (less efficient, more Ca).
Vitamin A deficiency – symptoms
ocular signs known as xerophthalmia, of which the earliest sign is night blindness.
Vitamin D deficiency – symptoms
.
rickets, hypocalcaemia, hypophosphataemia.
Vitamin E deficiency –symptoms
tocopherol (vitamin E) deficiency can be associated with a progressive sensory and motor neuropathy (proprioreceptive), spinocerebellar ataxia, retinal degeneration (pigmented retinopathy and loss of vision), and a haemolytic anaemia.
Vitamin K deficiency –symptoms
bleeding diathesis
What influences the magnitude of L>R shunt in ASD?
Size of defect + RV/LV compliance
What causes 3rd heart sound
Rapid ventricular filling- volume overload conditions
What part of the heart does pulmonary wedge pressure (5-12mmHg) approximate?
Indirect measure of the mean left atrial pressure. A catheter (e.g. Swan-Ganz catheter) is floated through the right heart into a branch of the pulmonary artery and the balloon is inflated, occluding the artery and blocking the incoming flow of blood. The tip of the catheter, which lies beyond the balloon, is connected to a pressure transducer. As this column of blood is connected to the left atrium via a bed of pulmonary capillaries and pulmonary veins, the pressure measured by the catheter tip will reflect the distal LA pressure (normally 5-12 mmHg).
What part of the heart does pulmonary wedge pressure (5-12mmHg) approximate?
Indirect measure of the mean left atrial pressure. A catheter (e.g. Swan-Ganz catheter) is floated through the right heart into a branch of the pulmonary artery and the balloon is inflated, occluding the artery and blocking the incoming flow of blood. The tip of the catheter, which lies beyond the balloon, is connected to a pressure transducer. As this column of blood is connected to the left atrium via a bed of pulmonary capillaries and pulmonary veins, the pressure measured by the catheter tip will reflect the distal LA pressure (normally 5-12 mmHg).
When do the paranasal sinuses develop/become pneumatized?
Birth- only ethmoidal sinuses are pneumatized
Maxillary sinuses are not pneumatized until 4 years of age
Sphenoidal sinuses present by age 5, frontal sinuses develop at age 7-8
What is the narrowest component of the upper airway in infants
Subglottis
What is FEF25-75 used to measure
FEF25-75 (maximum mid-expiratory flow rate) = flow in smaller airways, most effort dependant portion of curve, measures milder obstruction.
Patterns on spirometry with obstructive (extrathoracic & intrathoracic, fixed & variable) diseases
Obstruction- ↓ FEV1, N FVC, ↓ FEV1/FVC ratio
- Bronchodilator response: >12% change in FEV1 dx
- Provocation test: >15-20% change methacholine, histamine, saline
Fixed obstruction- flattening of curve both insp & exp
- glottic/subglottic lesion
Variable extrathoracic obstruction: flattening only on INSPIRATION (curve is upper)
- laryngeal/tongue pathology
Variable intrathoracic obstruction: flattening only on EXPIRATION (curve is lower)
- bronchomalacia/lower tracheal pathology
Sawtooth pattern- neuromuscular disease
Small hump in loop-
Patterns on spirometry with restrictive disease
Restrictive ↓FEV1, ↓FVC, N FEV1/FVC ratio
Patterns on spirometry with poor technique, cough- operator effects
Define normal sleep phases/cycle
Cycles 90-120min
- Infants 40mins
- Young children 50-60mins
- NREM (stage 1-4)
Stage 1 lightest
Stage 2 intermediate sleep 40-50% total sleep time
Stage 3 and 4 deep/restful sleep (20% time) - REM sleep = Rapid Eye movement
20% of adult sleep, 50% of infant sleep
- Low muscle tone, decreased TV/irregular breathing
- Nightmares/dream
- Consolidation of memory/plasticity
Define stages of sleep/normal durations
Normal napping
1 year old 2 naps per day
2 year old 1 nap per day
5 year old No napping
Normal sleeping
Approximate = 16 – age (only from birth to sleep time 9hrs, stable in adolescents)
Birth 16 hours
2 years 14 hours
6 years 10 hours
18 years 8 hours
Adult 7 hours
What are common changes to sleep patterns with age
There is a gradual decline in the average 24 hour sleep duration from infancy through adulthood
Average adolescent still requires 9-9.25 hours of sleep per night
Naps typically cease at age 5 years
Decline in the relative percentage of REM sleep from birth (50%) to early childhood into adulthood (25-30%)
SWS – peaks in early childhood, drops off abruptly after puberty, and then further decreases
Why is NO administered via ETT as close to patient as possible?
NO is usually fed into the ventilator tubing as close to the patient as possible, limiting the mixing time between O2 and NO- forms toxic compounds i.e NO2 (can damage resp tract)
Median nerve supplies all motor in flexor compartment except
- Thenar compartment
- 2x Lumbricals (LOAF)
EXCEPT FCU and medial half of FPD
Erbs vs Klumpkes palsy
E before K
Erbs = upper brachial plexus C5-6, porters tip hand, adducted/medialy rotated, pronated/externally rotated
- affects deltoids, biceps, brachialis,
Klumpkes = lower brachial plexus C8-T1
- Claw hand- intrinsic hand muscles/ulnar flexors weak, unopposed
- +/- Horners, vasoactive changes
What nerve supplies anatomical snuffbox sensation
Radial
What muscles does the ulnar nerve supply?
Medial 2 lumbrical = flex the MCP, extend the IP joints of little + ring fingers
Interossei = abduct and adduct the fingers
Hypothenar muscles
Adductor pollicis
When does a childs eGFR reach adult levels (per equivalent BSA)?
2 yrs
Example of ‘two hit hypothesis’ in paediatric cancers?
Retinoblastoma
two mutations (two hits) of key genes in the control of cell division occurring in a retinal neuro-ectodermal cell were necessary for the development of retinoblastoma
What is the main advantage of whole genome sequencing when compared to whole exome sequencing?
Intrinsic mutations are detected
Most common injury in NAI?
Metaphyseal corner fracture
Which cells produce Anti-Mullerian Hormone?
Sertoli cells
Say no to mother
Mechanism of action of Sildenafil?
cGMP-specific phosphodiesterase inhibitor
Mechanism of action of Sildenafil?
cGMP-specific phosphodiesterase inhibitor
Management of EPSE with metaclopramide (oculogyric crisis)
Benztropine (anti-cholinesterase)
What gene is responsible for the cardiovascular phenotype in Williams syndrome?
ELN
‘Elvin Facies’
Blood findings in C1Einh/HAE?
Low C4, low C1-esterase inhibitor level, low C1-esterase inhibitor function
Which CSF metabolite is the most sensitive marker of inflammation?
Neopterin
Which autoinflammatory condition is associated with a gene defect in pyrin?
Familial mediterranean fever
‘Family festive pyre = pyrin’
What anti-epileptic drug demonstrates irreversible inhibition of GABA transaminase?
Vigabatrin
What is the term for the point of maximal absorption of a solute by the renal tubule?
Transport maximum
What protein is affected in NMO?
Aquaporin 4
What cell type accounts for increased immunity provided by conjugated pneumococcal vaccines in comparison to un-conjugated pneumococcal vaccines?
CD4
Where does the oesophagus originate from? What is its length at birth, when does it reach adult length?
Post-pharyngeal forgut
Length of esophagus is 8-10 cm at birth and doubles in the first 2-3 years of life to reach 25cm in adult
When is swallowing first seen?
Swallowing seen as early as 16-20 weeks in utero
-Polyhydramnios is the hallmark of lack of normal swallowing or esophageal upper GI obstruction
What are the landmarks surrounding the oesophagus?
Relation to adjacent structures
Prevertebral fascia posteriorly
Trachea/ L mainstem bronchus/ heart anteriorly
Fixed at origin
Mobile throughout mediastinum
Structure of stomach? Innervation?
Wall: mucosa>submucosa>muscularis>serosa
Epi: simple columnar
2x sphincters:
- LES (smooth muscle)
- pyloric (allows passage into duodenum once fluid consistency- ‘chyme’)
Stomach is surrounded by parasympathetic (stimulant) and sympathetic (inhibitor) plexuses which regulate both the secretions activity and motor activity of the muscles
Interstitial cells of Cajal are specialised pacemaker cells located in the wall of the stomach, small intestine and large intestine – responsible for migrating motor complex which result in waves in peristalsis
The epithelium and lamina propria are by tubular glands
Cells in stomach- what hormones/enzymes released?
Oxynctic/parietal cells: HCL (upper stomach)
Chief cells: pepsinogen (activated by HCL, deactivated alakaline in duodenum)
Enterochromaffin like cells: histamine (lower stomach)- regulate digestive hormones
G cells: gastrin
Mucous cells: mucus
Cells in stomach- what hormones/enzymes released?
Oxynctic/parietal cells: HCL (upper stomach, stimulated by Gastrin- G cells, ACh- PNS, M3 receptors/histamine- cAMP mediated = all increase H/K ATP-ase pump)
G cells: gastrin (release histamine & thereby acid, ^ intracellular calcium)
Enterochromaffin like cells: histamine (lower stomach, stimulates acid secretion)
Chief cells: pepsinogen (activated by HCL, deactivated alakaline in duodenum)- proteolytic,
Mucus cells: mucus
Structure, length, wall of small intestine
270cm at birth- 450/550 by 4yrs
Mucosa with villii (present by 8 weeks gestation duodenum, 11weeks age ileum)
Goblet cells = mucus
Paneth cells- lysozyme/phospholipase, defensins
Brunner cells- HCO3 mucus- alkalinisation of HCL from stomach
Peyer patches = lymphatic/lymphocytes
Plicae circulares- mucosa/submucosa
Hormonal signalling in SI when food enters:
Increased gastric secretions- intestinal phase of eating (PNS- vagal)
Enterogastric reflex- inhibits stomach secretions
GIP also inhibits gastric secretion
CCK release: triggers GB/hepatic secretions
Secretin: triggers HCO3 into GB/hepatic secretions
Large intestine, length, structure, function
75-100cm
Absorption of water/electrolytes
Storage and expulsion of faeces
Taenia coli- muscle, contract to form haustra
Iron absorption
Duodenum
Folic acid absorption
Duodenum & jejunum
CHO absorption
Jejunum, proximal 100-200cm
Protein absorption
Proximal 100-200cm intestine
Fats, FFA, monoglycerides (micellar complexes) absoprtion
Throughout small intestine
FFA/TG- prox 100-200cm
MCT- via portal circulation
Distal ileum, fatty acids
B12 absorption
Terminal ileum
Bile salt absorption
Terminal ileum
Water & electrolyte absorption
Colon
Water soluble vitamin absorption
Jejunum/proximal 100-200cm
C/M/P absorption
Duodenum & jejunum
Brush-border oligo/disaccharidases & carbohydrates produced:
Glucoamylase + dextrinase = maltose
Sucrase-isomaltase
Sucrose 🡪 glucose + fructose
Maltose 🡪 glucose + glucose
Effective against 1:6 alpha linkages
Lactase
Lactose 🡪 glucose + galactose
Absorption of glucose, galactose & fructose
Apical:
Glucose + galactose – Na+ dependent glucose transporter (SGLT1) [basis of ORS]
Fructose – facilitated diffusion via GLU5
Basolateral
All by GLUT2
Carbohydrate requirement & digestion
200-300gm/d, 50% of energy req
Mouth: amylase
Intestine: salivary amylase reactivated, pancreatic amylase release (stimulated by CCK)
Protein requirement and digestion
0.75g/kg/d
Stomach: pepsin- hydrolyses bonds (chief cells- cAMP/intracellular Ca- PNS/CCK/gastrin)
Duodenum: CCK = secretion & activation of proteases- trypsin, elastase, carboxypeptidase A&B
Function of pancreatic peptidases
Endopeptidases = trypsin, chymotrypsin, elastase
Act at interior peptide bonds
Exopeptidases = pancreatic carboxypeptidases
Act on terminal amino acids
Function of pancreatic peptidases
Endopeptidases = trypsin, chymotrypsin, elastase
Act at interior peptide bonds
Exopeptidases = pancreatic carboxypeptidases
Act on terminal amino acids
Absorption of peptides/oligopeptides?
Neonates: antigens, Iggs
Enterocytes- endocytose
Brush border: amino acid transporters, peptides via active transport (jejunum), faster than AAs
Further digestion intracellularly
Basolateral: 3+/2+ Na dependant, 10% as small peptides
Fat requirement, digestion & absorption?
120-150g, biliary lipid 40-50g
- form fats/oils/membranes/skin lipids
Stomach: emulsification- peristalsis/gastric& lingual lipase
Pancreatic lipase: CCK stimulates release, trypsin activates colipase
Hydrolyses 1,3 bonds
Form micelles in SI- can be absorbed via SI wall
FA <12 C direct to portal system (ie. MCT)
FA >12 C re-esterified to TG
FFA/MGs for chylomicrons in enterocytes- travel to lacteals and enter lymphatics
Less efficient in neonates
B1 deficiency sx?
Beriberi (diffuse polyneuropathy due to myelin + axonal degeneration)
Infantile Form (Mo deficient, breastfeeding) sudden onset heart failure, absent deep tendon reflexes, aphonia
Wernicke-Korsakoff
B2 (riboflavin) deficiency sx?
Poor growth/FTT
Angular cheilitis, stomatitis
Moist scaly skin, seborrheic dermatitis
Normocytic normochromic anemia
Eyes- photophobia, itch, blurred vision, neovascularisation
B3 (niacin) deficiency Sx
Pellagra (diarrhoea, dementia, dermatitis)
Glossitis, stomatitis, swollen tongue, ulcers
B5/B6 deficiency sx?
B5 (panthenoic acid) Rare, paraesthesias
B6 (pyridoxine): Neuro – irritability, convulsions
Hypochromic anaemia
Isoniazid – needs B6 or get peripheral neuritis
B12 (cobalamin) deficiency sx?
Megaloblastic anemia
Neuro (demyelination, subacute combined degeneration of spinal cord, optic atrophy) 🡪 ataxia, paraesthesia, periph neuropathy
Should not use nitrous oxide in individuals with B12 deficiency
Folate deficiency sx?
Macrocytic anaemia
Neural tube defects in fetus
Vit C deficiency sx?
Scurvy
Petechiae, ecchymoses, gingivitis
Follicular hyperkeratosis, coiled hairs
Vit A deficiency sx?
Eye disease
Night blindness
Retinopathy
Xerophthalmia
Keratomalacia
Keratinization – bitot spots
Poor bone growth
Nonspecific skin problems – hyperkeratosis
Immune system impairment (B + T cell) - measles
Growth failure
Vit E deficiency sx?
Haemolytic anaemia
Neuropathy
Spinocerebellar syndrome w variable involvement of peripheral nerves
Ataxia
Hyporeflexia
Loss of proprioceptive + vibratory sensation
Myopathy
Skeletal myopathy
Development of nephron
Metanephric mesenchyme invades ureteric bud (from Wolffian duct)- forms renal vessicle which produces BC/prox tubule/LOH, Ureteric bud forms collecting duct, major/minor calyces
Nephron number complete by 34-36wks
Stages of nephrogenesis
Arises from mesoderm
4th week- pronephros (disintegrates to produce mesonephros)
5th-6th week- metanephros- definitive adult kidney
28-32wks - mesonephros - paired tubules that produce urine, also contributes to bladder formation
Blood supply to the abdominal viscera (SI, stomach, pancreas, spleen, liver)
- Coeliac axis off abdominal aorta
R) = common hepatic artery (20-30% of blood supply, rest via portal vein)
- Gastroduodenal artery: inner stomach curvature
- Duodenal branch: duodenum
- Proper hepatic artery: liver
- R) hepatic artery > cystic artery: GB
- Anterior/posterior & superior pancreatoduodenal artery: pancreas & duodenum
L) = L) gastric artery & splenic artery
- Splenic > R) gastroomental artery
- Pancreatic branches
- SMA off abdominal aorta
- Supplies midgut
- R) colon & mesentery - IMA off abdominal aorta
- Supplies hindgut
- L) colon & mesentery
What is the function of the spleen?
Lymphoid (white pulp)
- Contains B cells in germinal centres
- Haematopoesis 3-6mo in utero
Filtration (red pulp)
- Sinuses/reticular system with macrophages
- Destruction of old RBCs
Host defence (marginal zone)
- Pickup organisms- dendritic cell/APC rich
- particularly encapsulated (H.IB, strep pneumo, neisseria + protazoa)
Most likely lymphadenopathy in viral infection?
Submandibular/superior deep cervical nodes:
- Drains the cheek, nose, lips, anterior tongue, submandibular gland, buccal mucosa.
- Affected in 80% of children with URTI
Cervical lymph node drainage?
Submandibular: Drains the cheek, nose, lips, anterior tongue, submandibular gland, buccal mucosa.
Superficial cervical: Drains the skin, lower larynx, parotid, lower ear canal.
Submental : Drains the central lower lip, floor of mouth, tongue
Posterior auricular: Drains the temporal and parietal scalp.
Aortic arch formation
1st = Max (maxillary)
3rd = 3=c Carotid (also looks like bunny teeth = carrot)
4th = 4 limbs (descending aorta)
6th = 2 lungs back to back (PA)
What part of foetal circulation receives the highest SpO2?
Placenta > UV (80%) > liver (ductus venosus) > IVC > RA (also 25% via lungs/PDA) shunt to LA (67%) > head 62% > descending aorta
SpO2/pressures in normal heart circulation
Surfactant proteins & function. What is ABCA3?
Surfactant: produced in Type 2 alveolar cells, decrease surface tension in alveoli to increase compliance
Surfactant protein A, D- larger glycoproteins
- Involved in innate immunity
Surfactant B/C
- Surface tension lowering
- Surf B deficiency most common
Timing of umbilical cord seperation? Disorders with delayed?
21 days
If > 1mo, consider neutrophil defects- i.e LAD, Chediak Higashi, WAS, RAC2 deficiency
What stages do first and second heart sound correspond to?
S1- closure of AV valves
- End of diastole, start of isovolumetric contraction
S2- closure of PA/Ao
- End of systole
- Start of diastole
Most significant factor influencing airflow through a tube?
Radius of tube
What stage of sleep do K complexes/sleep spindles occur?
NREM 2
What cell mediates type 4 hypersensitivity?
CD8 T cell
What is Ara H2?
A storage protein with trypsin inhibition properties
Food allergen with associated familial inheritance?
Peanut
Absorption of solutes across nephron? Where is water NOT absorbed?
Most likely cause of proteinuria on dipstick?
Haematuria
How many hormones does the anterior pituitary secrete?
How many secretory cell types are there?
6 (FSH,LH, GH, CRH, PRL, TSH, ACTH)
5 cell types:
Somatotrope (GH): 50%
Lactotrope (PRL): 10-30%
Gonadotrope (FSH/LH): 20%
Corticotrope (ACTH): 10%
Thyrotrope (TSH): 5%
What vitamin excess causes increased ICP?
Vitamin A
Cortical dysplasia involving insula- symptoms
Seizures
- Choking sensation
- Drug resistant epilepsy
Definition of segregation in genetics?
Determination of whether or not the variant of interest is present in the parents
Structure of Hb?
Two alpha globin chains, two beta globin chains, four heme groups
Upper limb myotomes
Lower limb myotomes
How much blood can a neonate lose into a subgaleal
250-75ml (80%!!!)
Kcal/kg per day for prem neonate vs term
120- prem
100- term
Phase 0 cardiac cycle?
Voltage gated Na+ channel
Phase 1 cardiac cycle?
K+ channel
Phase 2 cardiac cycle?
L-type Ca2+ channel in /K+ & Cl- out
Phase 3 cardiac cycle?
K+ out
Phase 4 cardiac cycle?
RMP- K+ inward rectifier
Erb vs Klumpke’s palsy
Erb = waiter tip, C5,6,7
(tip me a 5er)
Klumpke = claw, C8,T1
(bottom of plexus, creepy & lives under a bridge)
Differences between gas exchange and conducting airways?
Conducting = terminal bronchioles
- Patency determined by cartillage
- High velocity/resistance to airflow
Gas exhcnage
- Resp bronchioles, alveolar ducts and alveoli
- Small caliber, large number/SA (larger apices >bases)
- Low resistance to airflow, non turbulent/low velocity
- Patency determined by negative pressure
Features of respiratory membrane, type1 & 2 alveolar cells?
Respiratory membrane = barrier between alveolar air and blood
- Squamous alveolar cell (type 1)
- Basement membrane (shared)
- Squamous endothelial cell of capillary (pulmonary arterial supply)
MAP 10mmHg, oncotic pressure 25mmHg, thickness 0.5mm
Type 1 = 95%- surface for gas exchange
Type 2 = 5%- produce surfactant (cuboidal), repair epithelium
Central control of respiration
Aim: pH 7.4, pO2 100mmHg, pCO2 40mmHg
Brainstem
- Inspiritory centre DRG
- Expiratory centre VRG
- pneumotaxic = rate/pattern, limits expoiration
Motor cortex/limbic = conscious control
Central chemoreceptors (CO2/CSF H+)
- Medulla
- ↑ PaCO2 → ↑ CSF [H+] → ↑ ventilation
Peripheral chemoreceptors (pO2/pH)
- Carotid bodies
- Respond to ↓ PaO2, ↓ pH, ↑ PaCO2 → ↑ ventilation
Other receptors
Stretch: Herring-Breuer reflex- excessive inflation triggers this reflex which is protective to further inflation as it inhibits inspiratory neurons
Irritant - bronchocontriction/cough
J receptors - oedema, ^RR/shallow breathing
Baro/pain/temp receptors
Formula for compliance?
Compliance = change in volume/ change in pressure
Distensibility of substance
- Reciprocal to elastance
- More compliant = expands easily
Formula for resistance
Poiseulle’s law
R = 8xlength x viscosity / pi radius^4
Length and viscosity constant = radius main factor
Nasal airway = 40-50% of total resistance
Factors that affect lung compliance?
- FRC (age, body size, posture)
- Lung volume (resection, collapse, consolidation)
- Lung elasticity (pulmonary oedema, fibrosis decrease)
Factors that affect lung compliance?
- FRC (age, body size, posture)
- Lung volume (resection, collapse, consolidation)
- Lung elasticity (pulmonary oedema, fibrosis decrease)
How is carbon dioxide transported around the body?
Carbon dioxide
- 90% transported as carbonic acid
(CO2 + H2O – H2CO3 – HCO3 + H+)
- Enzyme = carbonic anhydrase
5% carbamino-compounds – bound to haemoglobin and other proteins
5% dissolved in plasma
Causes of hypoxemia, hypercapnea?
Low O2
- Hypoventilation
- Diffusion limitation
- Shunt
- V/Q mismatch
High CO2
- Hypoventilation
- V/Q mismatch
