Integumentary System

InCheat Sheets / Embryology

Briefly describe the development of the skin
- The epidermis (Epithelium) is derived from the ectoderm.
  - Wnt Signalling → decreased response to FGF → Promotes response to BMP → Differentiation into embryonic epidermis
  - Lack of Wnt signalling → response to FGF → decreased response to BMP → Neurogenesis (Differentiation into neuroectoderm)
- Appendages form when the primitive epidermis invaginates into the dermis. The cells differentiate into their corresponding types: follicle cells, eccrine sweat gland cells, apocrine sweat gland cells
- The dermis is derived from teh mesoderm
- Melanocytes, Langerhans cells, and Merkel cells are derived from neural crest cells. They migrate to the epidermis startig from the 12th week of development.

Dr Jeffrey Kalei

Author and illustrator for Hyperexcision. Interested in emergency room medicine. I have a passion for medical education and drawing.

Active question

Responded question

Skipped question

Biochemistry

Adrenocorticotrophic hormone	P: <80 ng/L
Alanine aminotransferase (ALT)	P: 5–35 U/L
Albumin	P: 35–50 g/L
Aldosterone	P: 100–500 pmol/L
Alkaline phosphatase	P: 30–130 U/L (adults)
α-Amylase	P: 0–180 IU/dL
α-Fetoprotein	S: <10 kU/L
Angiotensin II	P: 5–35 pmol/L
Antidiuretic hormone (ADH)	P: 0.9–4.6 pmol/L
Aspartate transaminase	P: 5–35 U/L
Bicarbonate	P: 24–30 mmol/L
Bilirubin	P: 3–17 μmol/L
BNP	P: <50 ng/L
C-reactive protein	P: <10 mg/L
Calcitonin	P: <0.1 mcg/L
Calcium (ionized)	P: 1.0–1.25 mmol/L
Calcium (total)	P: 2.12–2.60 mmol/L
Chloride	P: 95–105 mmol/L
Cholesterol	P: <5.0 mmol/L
VLDL	P: 0.128–0.645 mmol/L
LDL	P: <2.0 mmol/L
HDL	P: 0.9–1.93 mmol/L
Cortisol	P: AM 450–700 nmol/L, Midnight 80–280 nmol/L
Creatine kinase (CK)	P: ♂ 25–195 U/L, ♀ 25–170 U/L
Creatinine	P: 70–100 μmol/L
Ferritin	P: 12–200 mcg/L
Folate	S: 2.1 mcg/L
FSH	P/S: 2–8 U/L ♂ (luteal); >25 U/L menopause
Gamma-glutamyl transpeptidase	P: ♂ 11–51 U/L, ♀ 7–33 U/L
Glucose (fasting)	P: 3.5–5.5 mmol/L
Growth hormone	P: <20 mu/L
HbA1C (DCCT)	B: 4–6%
HbA1C (IFCC)	B: 20–42 mmol/mol
Iron	S: ♂ 14–31 μmol/L, ♀ 11–30 μmol/L
Lactate	P: Venous 0.6–2.4 mmol/L, Arterial 0.6–1.8 mmol/L
Lactate dehydrogenase (LDH)	P: 70–250 U/L
Lead	B: <1.8 mmol/L
LH	P: 3–16 U/L (luteal)
Magnesium	P: 0.75–1.05 mmol/L
Osmolality	P: 278–305 mosmol/kg
Parathyroid hormone (PTH)	P: 0.8–8.5 pmol/L
Potassium	P: 3.5–5.3 mmol/L
Prolactin	P: ♂ <450 U/L, ♀ <600 U/L
PSA	P: 0–4 mcg/mL
Protein (total)	P: 60–80 g/L
Red cell folate	B: 0.36–1.44 μmol/L
Renin	P: Erect 2.8–4.5, Recumbent 1.1–2.7 pmol/mL/h
Sodium	P: 135–145 mmol/L
TBG	P: 7–17 mg/L
TSH	P: 0.5–4.2 mU/L
Thyroxine (T4)	P: 70–140 nmol/L
Free T4	P: 9–22 pmol/L
Total iron-binding capacity	S: 54–75 μmol/L
Triglycerides (fasting)	P: 0.50–2.3 mmol/L
Triiodothyronine (T3)	P: 1.2–3.0 nmol/L
Troponin T	P: <0.1 mcg/L
Urate	P: ♂ 210–480 μmol/L, ♀ 150–390 μmol/L
Urea	P: 2.5–6.7 mmol/L
Vitamin B12	S: 0.13–0.68 nmol/L
Vitamin D	S: 50 nmol/L

Arterial Blood Gases

pH	7.35–7.45
PaCO₂	4.7–6.0 kPa
PaO₂	>10.6 kPa
Base excess	±2 mmol/L

Urine

Cortisol (free)	<280 nmol/24h
Hydroxyindole acetic acid	16–73 μmol/24h
Hydroxymethylmandelic acid	16–48 μmol/24h
Metanephrines	0.03–0.69 μmol/mmol creatinine
Osmolality	350–1000 mosmol/kg
17-Oxogenic steroids	♂ 28–30 μmol/24h, ♀ 21–66 μmol/24h
17-Oxosteroids (neutral)	♂ 17–76 μmol/24h, ♀ 14–59 μmol/24h
Phosphate (inorganic)	15–50 mmol/24h
Potassium	14–120 mmol/24h
Protein	<150 mg/24h
Protein/creatinine ratio	<3 mg/mmol
Sodium	100–250 mmol/24h

Haematology

WCC	4.0–11.0 ×10⁹/L
Red cell count	♂ 4.5–6.5 ×10¹²/L, ♀ 3.9–5.6 ×10¹²/L
Haemoglobin	♂ 130–180 g/L, ♀ 115–160 g/L
PCV / Haematocrit	♂ 0.4–0.54 L/L, ♀ 0.37–0.47 L/L
MCV	76–96 fL
MCH	27–32 pg
MCHC	300–360 g/L
RDW	11.6–14.6%
Neutrophils	2.0–7.5 ×10⁹/L (40–75%)
Lymphocytes	1.0–4.5 ×10⁹/L (20–45%)
Eosinophils	0.04–0.44 ×10⁹/L (1–6%)
Basophils	0–0.10 ×10⁹/L (0–1%)
Monocytes	0.2–0.8 ×10⁹/L (2–10%)
Platelet count	150–400 ×10⁹/L
Reticulocyte count	0.8–2.0% / 25–100 ×10⁹/L
ESR	Depends on age
Prothrombin time	10–14 s
APTT	35–45 s

Paediatric

Pulse Rate (beats per minute)
Neonate (<1 month)	140–160
Infant (<1 year)	120–140
1–5 years	110–130
5–12 years	80–120
>12 years	70–100
Temperature
Normal range	36.6–37.2 °C
38.0 °C	Fever (infant)
38.5 °C	Fever (>3 months)
Respiratory Rate (tachypnoea)
Neonate (0–2 months)	≥60 breaths/min
2–12 months	≥50 breaths/min
1–5 years	≥40 breaths/min
>5 years	≥30 breaths/min
Blood Pressure (mmHg)
Term	65/45
1 year	75/50
4 years	85/60
8 years	95/65
10 years	100/70
Head Circumference
Term	35 cm ± 2
1 year	+1 cm/month
2–3 years	+2 cm/year
4–5 years	+1 cm/year
5 years	~53 cm
10 years	56–57 cm
Height
Term	52–55 cm
1 year	75 cm
2–12 years	6a + 77 cm
Weight Formulas
3–12 months	(a + 9)/2 kg
1–6 years	2a + 8 kg
>6 years	(7a − 5)/2 kg
Developmental Milestones
Social smile	1.5 months
Head control	4 months
Sits unsupported	7 months
Crawls	10 months
Stands unsupported	10–12 months
Walks	12–13 months
Talks	18 months
MUAC (6 months–5 years)
Obese	>17.5 cm
Normal	13.5–17.4 cm
At risk	12.5–13.4 cm
Moderate malnutrition	11.5–12.4 cm
Severe malnutrition	<11.5 cm
Blood Transfusion
Whole blood	20 mL/kg
pRBC	10 mL/kg
Formula	6 × (weight in kg) × Hb deficit
Normal Paediatric Lab Values
Haemoglobin (g/dL)	Hematocrit (%)
Term newborn: 13–20	40–58
1 month: 11–18	32–54
2 months: 10–15	28–44
1–2 years: 10–13	32–40
>2 years: 11–14	33–42
CSF WBC (/mm³)
Term newborn	0–25
>2 weeks	0–5

Dr Jeffrey Kalei

Explore

Anatomy Mock Exam 1

Purines and Purine Metabolism

Tetrahydrofolate Synthesis

Post DiscussionCancel Reply