Right side of heart - Deoxygenated RBCs from the body --> Superior and inferior vena cava --> Right atrium --> Tricuspid valve --> Right ventricle --> Pulmonary semilunar valve --> Pulmonary Trunk --> Pulmonary arteries --> lungs

Left side of heart - Oxygenated RBCs from the lungs --> Pulmonary veins --> Left atrium --> Bicusipid valve --> Left ventricle --> aortic semilunar valve --> Aorta --> the boys systemic circulation

Veins: Carry blood towards heart; deoxygenated except for pulmonary circulation and umbilical vessels of fetus

Venules:

• capillaries unite to form post capillary venules

  
  

  -consists of endothelium and a few pericytes

  
  

  -very porous; allow fluids and WBCS into tissue

  
  

• larger venules have one or two layers of smooth muscle cells

• have all tunics, but thinner walls with large lumens compare with corresponding arteries
• tunica media is thin, but tunica externa is stick
  -containsbcollagen fibers and elastic networks
• blood pressure lower than in arteries, so adaptations ensure return a blood to heart
  
  

OTHER ADAPTATIONS:

• Venous valve:*

  
  

  -prevent back flow of blood

  
  

  -most abundant in veins of limbs

  
  

• Venous sinuses:

  
  

  -flattened veins with extremely thin walls

Capillaries: Direct contact with tissue cells; directly severe cellular needs

• microscopic vessels; diameters so small only single RBC can pass at a time
• walls just in Tunica intima; in smaller vessels oneself forms entire circumference
• supply almost every cell
• Functions: Exchange of gases, nutrients, waste, hormones etc. between blood and interstitial fluid
  
  

Capillary beds: inner Wolven Nettwerk of capillaries between arterioles and venules

1. Vascular shunt: Channel that directly connects arterioles with venules (bypasses true capillaries)
2. Precapillary sphincter: act as valve regulating blood flow into capillary bed

Structure of all Blood Vessels:

1. Tunica intimate: inter-most layer that is "intimate" contact with blood
   -endothelium: simple squamous epithelium that lines lumen of all vessels
   
   2. Tunica media: middle layer composed mostly of smooth muscle & sheets of elastin

• sympathetic Vassar motor nerve fibers intervate this layer contracting

3. Tunica externa: outer most layer, also called tunica adventitia composed mostly of loose collagen fibers that protect and reinforce wall and anchor it to surrounding structures

Muscular arteries:

• elastic arteries give rise to muscular arteries
• also called distributing arteries because they deliver blood to body organs
• account for most of named arteries active in Vascoconstruction

Arterioles:

• smallest of all arteries
• control flow into capillary beds via Vascodilation and Vascoconstriction of smooth muscle
• also called resistance arteries because changing diameter change resistance
• lead to capillary beds

Elastic arteries: they called with the large, low resistance lumen, actors pressure reservoirs that expand and recoil as blood is ejected from heart

ECG: is a graphic recording of electrical activity

• composite of all action potentials at a given time; not a tracking of a single AP
• Electrodes are placed at various points on body to measure voltage difference
  
  

Main features:

• P wave: depolarization of SA node and atria
• QRS complex: regular depolarization and atrial repolarization
• T waves: ventricular repolarization
  P-R interval: beginning of atrial excitation to beginning of ventricular excitation
• S-T segment: tire ventricular myocardium depolarized
• Q-T interval: beginning of ventricular depolarization through ventricular repolarization

1. Sinoatrial (SA) node

• pacemaker of heart in right atrial wall
• generates impulse about 75 times/minute (sinus rhythm)
• impulse spreads across atria, and to AV node
  

2. Atrioventricular (AV) node - in inferior interatrial septum

   
   

3. **Atrioventricular (AV) bundle (bundle of his)

• in superior interventricular septum
• only electrical connection between atria and ventricles

4. Right and left bundle branches:

• two pathways in interventricular septum
• Carry impulses towards Apex of heart

5. Subendocardial conducting network:

• also referred to as Purkinje fibers
• complete pathway through interventricular septum into Apex and ventricular walls

Major Arteries:

• ascending aorta
• aortic arch
• thoracic aorta
• aorta abdominal
• Branchiocephalic trunk
• common carotid artery
• subclavian artery
• axillary artery
• branchial artery
• radial artery
• ulnar artery
• common iliac artery
• femoral artery
• anterior tibial artery
• fibular artery

Major veins: - cephalic vein

• basilic vein
• radial vein
• ulnar vein
• branchial vein
  axillary vein
• subclavian vein
• brachiocephalic vein
• superior vena cava
• internal jugular vein
• external jugular vein
• femoral vein
• great saphenous vein
• external iliac vein
  internal iliac vein
• common iliac vein
• inferir vena cava

Vital signs: pulse and blood pressure, along with respiratory rate and body temperature

Systolic pressure: pressure exerted in aorta during ventricular contraction

Diastolic pressure: lowest level of aortic pressure one heart is at rest

Radial pulse: (taken at wrist) most routinely use, but there are other clinically important post points

Pressure Points: areas where arteries are close to body surface

Venous BP:

1. Muscular pump: contraction of skeletal muscle "milks" blood back towards heart; valves prevent backflow

   
   

2. Respiratory pump: pressure changes during breathing move blood towards heart by squeezing abdominal veins as thoracic veins expand

   
   

3. Sympathetic venconstriction: under sympathetic control, smooth muscles construct, pushing blood back towards heart