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Anatomy & Physiology Key Concepts

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  • Difference between veins and arteries regarding valves

    Veins have valves to prevent backflow; arteries do not have valves.
  • Effect of decreased peripheral resistance on blood flow and hematocrit

    ↓ Peripheral resistance → ↑ blood flow → ↓ hematocrit concentration effect.
  • Relationship between hematocrit and blood viscosity

    ↓ Hematocrit leads to ↓ blood viscosity, which decreases resistance to blood flow.
  • Steps of RAAS in blood pressure regulation

    1) ↓ BP → 2) Kidneys release renin → 3) Angiotensin II forms → 4) Vasoconstriction + aldosterone release → 5) Na⁺ and water reabsorption → 6) ↑ blood volume → ↑ BP.
  • Role of ADH in blood pressure regulation

    ADH increases water reabsorption in kidneys, resulting in ↓ urine output and ↑ blood volume.
  • Frank-Starling Law of the heart

    ↑ End-diastolic volume (EDV) causes ↑ stroke volume; more filling results in a stronger contraction.
  • Sympathetic nervous system response to blood loss

    Blood loss ↓ blood volume → sympathetic activation → ↑ heart rate and ↑ cardiac output.
  • Concept of afterload in cardiac function

    ↑ Aortic pressure (e.g., atherosclerosis) requires ↑ ventricular pressure to open the aortic valve.
  • Effect of skeletal muscle contraction on venous return during exercise

    Muscle contraction compresses veins → ↑ venous return → ↑ preload on the heart.
  • Pathway of cardiac electrical conduction system

    SA node → AV node → Bundle of His → Purkinje fibers.
  • ECG wave components and their meanings

    P wave = atrial depolarization; QRS complex = ventricular depolarization.
  • Formula for cardiac output (CO)

    CO = HR × SV (heart rate times stroke volume).
  • Difference between endocrine and exocrine glands

    Endocrine glands secrete hormones into the bloodstream; exocrine glands secrete onto body surfaces or into ducts.
  • Example of lipid-soluble hormone

    Steroid hormones like cortisol are lipid-soluble.
  • Function of calcitonin hormone

    Calcitonin lowers blood calcium levels.
  • Normal blood pH range

    Normal blood pH is between 7.35 and 7.45.
  • Location of platelets after blood centrifugation

    Platelets settle into the buffy coat layer, not in plasma.
  • Functional layer of the endometrium during menstruation

    The functional layer is shed during menstruation and regenerated by the basal layer.
  • Optimal temperature for sperm production

    Sperm production is optimal below core body temperature.
  • Role of the epididymis in male reproduction

    Epididymis stores and matures sperm.
  • Chromosome number in human gametes

    Human gametes are haploid with 23 chromosomes.
  • Site of glucose and amino acid reabsorption in the nephron

    Proximal convoluted tubule (PCT) reabsorbs ~100% of glucose and amino acids.
  • Main site of nutrient absorption in the small intestine

    Most nutrient absorption occurs in the jejunum and ileum.
  • Function of the epiglottis

    Epiglottis prevents food from entering the trachea during swallowing.
  • Cause of edema related to capillary pressures

    Edema results from ↑ hydrostatic pressure or ↓ oncotic (protein) pressure in capillaries.
  • Role of atrial natriuretic peptide (ANP)

    ANP causes vasodilation and decreases blood pressure.
  • Difference between intrinsic and extrinsic blood flow control

    Intrinsic (myogenic) control is local; extrinsic control involves nervous and endocrine systems.
  • Surface area adaptations in the small intestine

    Circular folds, villi, and microvilli increase surface area for absorption.
  • Phases of respiration at rest

    Inspiration is active; expiration is passive.