BIO Cardiovascular System

Question 1

Heart

Answer 1

Location: behind the body of the sternum (mediastinum), base - below 2nd rib, apex - on the diaphragm

Question 2

Structure of the Heart

Answer 2

Pericardium: covers heart to reduce friction
Epicardium: outer layer
Myocardium: thickest, contractile
Endocardium: delicate inner layer

Question 3

Heart Chambers

Answer 3

Atria: receiving chambers, thinner myocardial wall (small-needs only a little pressure)
Ventricles: pumping chambers, thicker myocardial wall (L-Ventricle the largest)

Question 4

Heart Valves

Answer 4

Atrioventricular (AV) Valves: prevent back flow into atria
- Tricuspid Valve (R-AV valve): three flaps
- Bicuspid Valve (L-AV valve): two flaps
Semilunar (SL) Valves: prevent back flow into ventricles
- Pulmonary Valve
- Aortic Valve
Chordae Tendineae: attaches papillary mm to valves

Question 5

Electrical Conduction System of Heart

Answer 5

SA Node (pacemaker- initiates impulse to atria) > AV Node (inferior R-Atrium) > AV Bundle (Bundle of His-btwn ventricles) > Purkinje Fibers (med-lat walls of ventricles) = full ventricle contraction

Question 6

Cardiac Cycle

Answer 6

Atrial Systole: contraction of atria
- AV valves open, SL valves closed
- Begins with P-wave
Isovolumetric ventricular contraction: start of ventricular systole > AV valves closed & SL valves open (1st heart sound)
- Onset with R-wave
Ejection: SL valves open
- Onset with T-Wave (ventricles begin to
rest)
Isovolumentric ventricular relaxation: SL closure & opening of AV valves (2nd heart sound)

Question 7

Systole & Diastole

Answer 7

Systole: closing AV valves = 1st heart sound
Diastole: closing SL valves = 2nd heart sound

Question 8

Blood flow through the heart (R>L)

Answer 8

R-Atrium (from Vena Cava)> Tricuspid Valve > R-Ventricle > Pulmonary Valve > Pulmonary Artery - Arterioles - Capillaries - Venules - Veins > Pulmonary Veins > L-Atrium > Bicuspid Valve > R-Ventricle > Aortic Valve > Aorta > Arteries - Arterioles - Capillaries - Venules - Veins (organs) > Vena Cave

Question 9

Blood Vessel Types

Answer 9

Arteries: carry blood away from heart
  - systemic circuit (OX2)
  - pulmonary curcuit (CO2)
Arterioles: small arteries 
Capillaries: permit xchange of materials
Veins: carry blood towards heart
  - systemic circuit (CO2)
  - pulmonary curcuit (OX2)
Venules: small veins

Arteries > Arterioles > Capillaries > Venules > Veins

Question 10

(4) Tissue Types of Blood Vessels

Answer 10

Smooth M Fibers: exert tension when contracting, most numerous in elastic/muscular arteries
- not in capillaries
Elastic Fibers: allow recoil after distension
Collagen: provides structure, keep lumen open
Endothelial Cells (smooth inner surface): inhibits coagulation