Blood
What are the three main functions of blood?
Transport, regulation, and protection
Where is the heart located?
In the mediastinum, 2/3 to the left of midline
What are the three layers (tunics) of a vessel wall?
Tunica interna, tunica media, tunica externa
What is blood pressure and the normal value?
Pressure exerted by blood on vessel walls; 120/80 mmHg
What is hemoglobin and its function?
Iron-containing protein in RBCs that carries O₂ and CO₂
What hormone stimulates RBC production?
Erythropoietin (EPO)
Name the four chambers of the heart.
Right/Left atria and Right/Left ventricles
Which vessels act as blood reservoirs?
Veins and venules
List three factors that affect vascular resistance.
Lumen size, blood viscosity, and vessel length
What is the “lubb-dupp” sound caused by?
Lubb = AV valves close; Dupp = semilunar valves close
What are the three stages of hemostasis?
Vascular spasm, platelet plug formation, coagulation
What structure prevents valve cusp eversion during contraction?
Chordae tendineae attached to papillary muscles
What causes varicose veins?
Weak valves that allow backflow and pooling of blood
What do baroreceptors monitor?
Pressure/stretch changes in vessel walls
What law explains how preload affects contraction strength?
Frank–Starling law of the heart
What is hematocrit and what are the normal values for men and women?
% of RBCs in whole blood; Men 40–45%, Women 38–46%
Explain the path of electrical conduction through the heart.
SA node → AV node → Bundle of His → R/L bundle branches → Purkinje fibers
What are the two main pressures involved in capillary exchange?
Hydrostatic (pushes out) and Osmotic (pulls in)
What hormones regulate blood pressure?
ADH, ANP, epinephrine, norepinephrine, angiotensin II
What part of the circulation delivers oxygenated blood to tissues?
Systemic circulation
What are the differences between the extrinsic and intrinsic clotting pathways?
Extrinsic = faster, fewer steps, triggered by external trauma; Intrinsic = slower, triggered within blood vessel
What is cardiac output and its formula?
CO = Stroke Volume × Heart Rate (~5 L/min)
Describe the difference between arteries and veins.
Arteries = thick walls, high pressure; Veins = thin walls, low pressure, valves
Define venous return and name two mechanisms that assist it.
Volume of blood returning to heart; aided by skeletal muscle pump and valves
Explain how capillaries allow exchange.
Thin walls (one cell layer) allow diffusion of gases and nutrients