High Yield Year 1 Med

What structural features of RBCs increase their efficiency in oxygen transport?

Discoid shape (↑ SA:V ratio), thin membrane (↑ diffusion rate), pliable (pass through capillaries), 7μm diameter, no nucleus/organelles (more space for Hb).

What is the "Left at the Lungs" concept?

High O2 and pH → ↑ Hb affinity for O2 → Hb enters relaxed state → releases CO2, binds O2.

What is the Bohr Effect?

↑CO2, ↑2-3DPG, ↑temp, ↓pH → ↓Hb affinity for O2 → promotes O2 release in tissues.

What is the Haldane Effect?

High O2 and pH → ↓Hb affinity for CO2 → CO2 is released.

Mnemonic for stages of erythropoiesis?

Hey Mate Profitable Businesses Pollute Our Rural Environment.

List the stages of erythropoiesis in order.

Haematopoietic Stem Cell → Myeloid Progenitor → Proerythroblast → Basophilic Erythroblast → Polychromatic Erythroblast → Orthochromatic Erythroblast → Reticulocyte → Erythrocyte.

What changes occur during erythropoiesis?

Hb synthesis begins, nucleus and organelles ejected.

What would you see in iron deficiency anaemia?

Hypochromic microcytic RBCs.

What causes a left shift in the oxygen dissociation curve?

↓Temp, ↓CO2, ↓2-3DPG, ↑pH, ↑O2.

What activates the RAAS system?

Low blood volume/pressure.

How does RAAS increase BP?

Renin → Angiotensinogen → Ang I → Ang II via ACE → vasoconstriction, aldosterone, ADH → ↑Na+ and H2O reabsorption → ↑BP.

3 functions of angiotensin II?

Vasoconstriction, ADH release, aldosterone secretion.

Define Starling’s Forces.

Filtration pressure pushes water out; interstitial hydrostatic pressure pushes in; capillary colloidal pressure pulls in; interstitial colloidal pulls out.

How does the body respond to cold?

↓Temp sensed → hypothalamus → shivering, vasoconstriction → ↑temp.

How does the body respond to heat?

↑Temp sensed → hypothalamus → sweating, vasodilation → ↓temp.

What does ADME stand for?

Absorption, Distribution, Metabolism, Excretion.

Name 3 components of the plasma membrane.

Phospholipid bilayer, glycoproteins, cholesterol.

Name 3 compounds that can cross the lipid bilayer.

Oxygen, carbon dioxide, ethanol, water.

Primary vs Secondary haemostasis?

Primary = platelet plug; Secondary = fibrin mesh via coagulation cascade.

Steps in primary haemostasis?

Adhesion (vWF + GpIb), activation (platelet degranulation), aggregation (fibrinogen links platelets via GpIIb/IIIa).

What is heparin?

Antithrombin activator.

What is warfarin?

Vitamin K reductase inhibitor.

Difference between PT/INR and aPTT?

PT/INR = extrinsic pathway; aPTT = intrinsic pathway.

What does high INR indicate?

Bleeding risk.

3 parts of Virchow’s Triad and risk factors?

Stasis (immobility), hypercoagulability (dehydration), endothelial damage (smoking).

How does an action potential propagate?

Na+ influx (depolarisation) → K+ efflux (repolarisation) → hyperpolarisation → RMP.

Absolute vs Relative refractory period?

Absolute = no AP possible; Relative = AP possible with stronger stimulus.

Steps at neuromuscular junction?

Nerve fires → Ca2+ influx → ACh release → ACh binds receptor → Na+ influx → depolarisation → Ca2+ release → contraction.

Steps of muscle contraction (actin-myosin)?

Ca2+ binds troponin → myosin binds actin → ATP detaches it → ATP hydrolysis cocks it → binds further along → Pi release = power stroke.

How do AChE inhibitors work?

Block acetylcholinesterase → preserve ACh in cleft → prolonged stimulation.

Are AChE inhibitors agonists or antagonists?

Antagonists to AChE.

SNS vs PNS neurotransmitters?

SNS: Ach then NA/adrenaline; PNS: Ach then Ach.

What causes autonomic dysreflexia?

Noxious stimulus below T6 → ↑SNS → vasoconstriction → ↑BP → PNS can't override due to spinal injury.

Symptoms of autonomic dysreflexia?

Headache, flushing, sweating, blurred vision.

Function of DCML tract?

Tactile touch and proprioception.

Function of lateral spinothalamic tract?

Temperature and nociception.

Function of anterior spinothalamic tract?

Crude touch and pressure.

Neurogenic vs Spinal shock?

Neurogenic = ↓BP/HR; Spinal = ↓reflexes, flaccid paralysis.

Define dermatome and myotome.

Dermatome = area of skin from one spinal root; Myotome = muscles innervated by one motor neuron.

What are macronutrients broken into?

Carbs → monosaccharides; Proteins → amino acids; Lipids → glycerol + fatty acids.

Where does glycolysis occur?

Cytosol.

What are glycolysis outputs per glucose?

2 pyruvate, 2 NADH, 2 ATP.

Where does the Krebs cycle occur?

Mitochondrial matrix.

Krebs outputs per glucose?

6 NADH, 2 FADH2, 2 ATP, 4 CO2.

Where does ETC occur?

Inner mitochondrial membrane.

ETC outputs?

34 ATP, H2O, NAD+, FAD.

How does NADH make ATP?

Donates e⁻ → proton gradient → ATP synthase → 3 ATP.

What happens when no oxygen is present?

ETC stops → NAD+/FAD+ depleted → Krebs stops → anaerobic metabolism begins.

What does the Cori Cycle do?

Converts lactate to glucose (uses 6 ATP, makes 2 ATP).

Steps of lipid metabolism?

Mobilisation → Circulation → Uptake → Activation → Translocation → β-Oxidation → Oxidation.

Which micronutrients support bone health?

Calcium and Vitamin D.

What foods contain calcium and Vitamin D?

Milk and fish.