Physiology

Cytochrome P-450 (CYP450)

Family Members
CYP1 CYP1A1
CYP1A2
CYP2 CYP2A6
CYP2B6
CYP2C8
CYP2C9
CYP2C19
CYP2D6
CYP2E1
CYP3 CYP3A4
CYP3A5
CYP3A7

Cell Cycle Regulation

Body Fluid Distribution

Total Proportion Part Measurement
Body weight (BW) 3/5 Body fluid (BF) Heavy water
Body fluid (BF) 1/3 Extracellular fluid (ECF) Inulin & 22Na
Extracellular fluid (ECF) 1/4 Plasma 125I-albumin
Plasma 5/3 Blood 51Cr-RBC

Extracellular Fluid Changes

ECF Change BP RAAS ADH
Isotonic loss
Hypotonic loss
Hypertonic loss
Isotonic gain
Hypotonic gain
Hypertonic gain

Plasma Osmolality

Parameter 2 × Na + Glucose ÷ 18 + BUN ÷ 2.8
Na Serum sodium (mEq/L)
Glucose Serum glucose (mg/dL)
BUN Serum BUN (mg/dL)

Anion Gap (AG)

Parameter Na - (Cl + HCO3)
Na Serum sodium (mEq/L)
Cl Serum chloride (mEq/L)
HCO3 Serum bicarbonate (mEq/L)

Urine Anion Gap (UAG)

Parameter (Na + K) - Cl
Na Urine sodium (mEq/L)
K Urine potassium (mEq/L)
Cl Urine chloride (mEq/L)

Stool Osmotic Gap

Parameter POsmolality - 2 × (Na + K)
SOsmolality Stool osmolality (mOsm/kg)
Na Stool sodium (mEq/L)
K Stool potassium (mEq/L)

Physiological Effects of Electrolyte Disturbances

Sodium

Effects Hyponatremia Hypernatremia
Osmolarity

Potassium

Effects Hypokalemia Hyperkalemia
Resting membrane potential
Na channel activity
K channel activity

Calcium

Effects Hypocalcemia Hypercalcemia
Na channel activity
Ca-induced Ca release (CICR)
PTH

Potassium Shifts {I-DO-LABS}

Factor Serum K
Insulin
Digitalis
Osmolarity
Lysis of cells
Acidosis
β antagonists
Succinylcholine

Calcium Homeostasis

Regulator Target Actions
Calcitonin Bone ↓ Resorption
PTH Bone ↑ Resorption
  Kidney ↑ Reabsorption of Ca
↓ Reabsorption of phosphate
↑ 1α-hydroxylase
Vitamin D Bone ↑ Mineralization & Resorption
  Kidney ↑ Reabsorption of Ca & phosphate
  Intestine ↑ Absorption of Ca & phosphate

Oxygen Content

Parameter CaO2 = 1.34 × Hb × SaO2 + 0.0031 × PaO2
CaO2 Arterial O2 content (mL-O2/dL)
Hb Hemoglobin concentration (g/dL)
SaO2 Arterial O2 saturation (%)
PaO2 Arterial O2 pressure (mmHg)

Devine Formula of Ideal Body Weight (IBW)

Female

Parameter IBW = 45.5 + 2.3 × (H - 60)
IBW Ideal body weight (kg)
H Height (inch)

Male

Parameter IBW = 50 + 2.3 × (H - 60)
IBW Ideal body weight (kg)
H Height (inch)

Basal Energy Expenditure (BEE)

Female

Parameter BEE = (9.563 × W) + (1.850 × H) - (4.676 × Age) + 655.1
BEE Basal energy expenditure (kcal/day)
W Weight (kg)
H Height (cm)
Age Age (year)

Male

Parameter (13.75 × W) + (5.003 × H) - (6.775 × Age) + 66.5
BEE Basal energy expenditure (kcal/day)
W Weight (kg)
H Height (cm)
Age Age (year)

Respiratory Quotient (RQ)

Source Quotient
Anaerobic > 1
Carbohydrates 1
Protein 0.8
Fat 0.7

Skeletal Muscle Contraction

Crossbridge Cycling

Smooth Muscle Contraction

Autonomic Nervous System

Sympathetic

Target Effect
Adrenal gland -
Ciliary epithelium Aqueous humor
Blood vessels -
Bronchus Bronchodilation
Dilator pupillae Mydriasis
Heart Tachycardia
Juxtaglomerular cells Renin
Sphincter muscle :: GI -
Sphincter muscle :: GU -
Sweat gland Sweat
Sexual function Ejaculation

Parasympathetic

Target Effect
β islet cells Insulin
Bronchus Bronchoconstriction
Ciliary muscle Cycloplegia
Exocrine glands -
Heart Tachycardia
Smooth muscle :: GI Peristalsis
Smooth muscle :: GU Urination
Sphincter pupillae Miosis
Sexual function Erection

Autonomic Effects {DUMBBELSS}

Cholingeric Adrenergic
Diarrhea Constipation
Urinary incontinence Urinary retention
Miosis Mydriasis
Cycloplegia
Bronchoconstriction Bronchodilation
Bradycardia Tachycardia
Emesis -
Lacrimation Xerophthalmia
Salivation Xerostomia
Sweating Sweating

Signalling Pathways

Neurotransmitters

Pathways Receptors
Ionotropic receptor NN & NM & 5-HT3 & AMPA & NMDA & GABAA & Glycine
GqPCR M1 & M3 & α1 & 5-HT2 & H1
GsPCR β1 & β2 & D1 & 5-HT4 & H2
GiPCR M2 & α2 & D2 & 5-HT1 & GABAB & Opioid
RTK -
NRTK -
Steroid receptor -

Hormones

Pathway Receptors
Ionotropic receptor -
GqPCR TRH & GnRH & V1 & Oxytocin
GsPCR CRH & GHRH & V2
  TSH & ACTH & LH & FSH
  Calcitonin & PTH & Glucagon
GiPCR -
RTK Insulin & GF
NRTK GH & PRL & Cytokines
Steroid receptor TH & Mineralocorticoid & Glucocorticoid & SH
  • Receptor tyrosine kinase (RTK)
  • Non-receptor tyrosine kinase (NRTK)