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)