Introduction to Cardiovascular System

Question 1

Major Divisions of Circulatory System

Answer 1

• Pulmonary Circuit
  
  • right side of heart
  • Oxygen-poor blood–>Superior/Inferior Venae Cava–>Right Atrium–> Right Ventricle–>Pulmonary Trunk
  • Pulmonary trunk then sends oxygen poor blood to lungs for gas exchange
• Systemic Circuit
  
  • Left side of heart
  • Oxygenated blood leaves the lungs–> Pulmonary Veins–>Left Atrium–>Left ventricle–>Aorta
  • Aorta sends oxygenated blood to all tissues/organs
    
    • Ascending Aorta to:
      
      • Brachiocephalic
      • Left Common Carotid
      • Subclavian A.
    • Blood to Head and Neck

Question 2

Position/ Shape/Landmarks of Heart

Answer 2

• Location
  
  • B/w lungs
  • in mediastinum
  • Periacardium-surrouncs the heart
    
    • anchors heart to diaphragm, R & L lungs, Mediastinum
  • Apex tilts toward left lung
• Landmarks
  
  • 2nd intercostal space
    
    • top of heart
  • 5th intercostal space
    
    • bottom of heart
  • Sternum
    
    • anterior of heart
  • Midclavicle line
    
    • sides of heart
• Shape:
  
  • Base top portion
    
    • large vessels attach (coronary Vessels)
  • Apex bottom portion
  • Adult: weighs 10 ounces
  • Base to apex=5 inches
  • 3.5 inches wide
  • Always size of fist

Question 3

Chambers of the Heart

Answer 3

• R/L Atrium
  
  • Receive blood to return to heart
  • Auricles
    
    • on surface
    • enlarge chamber
• R/L Ventricles
  
  • Pump blood into ateries

Question 4

Atrioventricular sulcus

Answer 4

• seperates atrium and ventricles

Question 5

Interventricular Sulcus

Answer 5

• on top of the interventricular septum
• seperates the L & R ventricles

Question 6

Sulci

Answer 6

Coronary Arteries pass through

Question 7

Interatrial septum

Answer 7

• Wall that seperates atria

Question 8

Pectinate Muscles

Answer 8

• Internal ridges of myocardium
• in right atrium auricles

Question 9

Interventricular Septum

Answer 9

• Muscle
• seperates ventricles

Question 10

Trabeculae carneae

Answer 10

• internal ridges in both ventricles

Question 11

Valves (general definition)

Answer 11

• ensure one way blood flow through heart

Question 12

Atrioventricular Valves (AV)

Answer 12

• control blood flow b/w atria and ventricles
• Right AV valve
  
  • AKA tricuspid valve
  • three cusps
• Left AV valve
  
  • Aka Mitral/Bicuspid Valve
  • 2 cusps

Question 13

Semilunar Valves

Answer 13

• Control flow into great arteries
• Pulmonary Semilunar Valve
  
  • b/w right ventricle and pulmonary trunk
• Aortic Semilunar Valve
  
  • b/w left ventricle and aorta

Question 14

Chordae Tendineae

Answer 14

• Cords conect AV valves to papillary muscles on floor of ventricles
• prevent AV valves from opening when ventricles contract
• has 2-3 attachments to heart floor
  
  • distribute physical stress during systole
  • coordinate timing of electrical conduction (insulator)
  • Redundancy

Question 15

Heart Wall: Anatomy

Answer 15

• Epicardium
• Myocardium
• Endocardium

Question 16

Layers of Heart

-including pericardium

Answer 16

• Fibrous Skeleton
• Pericardium:
  
  • Parietal Pericardium
    
    • pericardial cavity
  • Visceral Pericardium
    
    • aka Visceral Epicardium
• Myocardium
• Endocardium

Question 17

Epicardium

Answer 17

• Aka visceral pericardium
• serous
• coronary blood vessels travel through
• thick layers of adipose

Question 18

Fibrous Skeleton

Answer 18

• aka Fibrous Pericardium
• framework of collagn and elastic fibers
• structual support
  
  • Keeps the heart in place
  • attachment for cardiac muscle
  • anchor valve tissue
• electrical insulation b/w atria and ventricles
  
  • important in timing and coordination of contractile activity (systole)

Question 19

Myocardium

Answer 19

• Cardiac muscle
  
  • muscle spirals aropund heart–>produces wringing motion
• proportional to workload
• Actual muscle of the heart

Question 20

Endocardium

Answer 20

• Smooth inner lining of heart and blood vessels
  
  • all four chambers
  • homologenous to tunica intima of blood vessels
• cover valve surfaces
• continuous with endothelium of blood vessels

Question 21

Pericardial Cavity

Answer 21

• Fluid filled space
• allows heart to move during contraction
• prevents friction between pericardium and mediastinum to prevent pericarditis

Question 22

Sub-endocardium

-histological

Answer 22

• has irregular collagen fibers that combine with surrounding collagen fibers of cardiac muscle
• contain:
  
  • Thick layer of CT
  • Small blood vessels & nerves
  • Purkinje fibers

Question 23

Purkinje fibers

Answer 23

• Pacemaker cells
  
  • propagate impulse to cardiac muscle in ventricles
• sub-endocardium
• larger than cardiac muscle cells
• few myofibrils and a lot of glycogen

Question 24

Vessels

Answer 24

• Layers
  
  • Tunica intima
  • Tunica media
  • Tunica Adventitia
• Parallel design
• Different function between arteries and veins

Question 25

Arteries vs Veins

• Pressure
• Permeability

Answer 25

• Arteries
  
  • designed for pressure
  • more tunica media
• Veins
  
  • designed for volume
  • thicker lumen
• Pressure:
  
  • Large artery> Medium Artery> Arteriole> Capillary>Venule> Vein
  • pressure has to be dimiinshed by the time it reaches capillaries for gas exchange and nutrients
• Permeability:
  
  • More surface area=more permeability
  • Capillary=greatest permeability

Question 26

Microcirculation

Answer 26

• Control of blood flow from heart–>large artery–>medium artery–> arterioles–>Metarteriole->precapillary sphincter–> capillary->Venule->veins–> superior/inferior vena cava–> heart
• Precapillary sphincter
  
  • determines when and what is exchanged
• Capillary-gas exchange

Question 27

What happens if the precapillary sphinctor contracts?

Answer 27

• closes gate
• deprive tissue of oxygen and nutrient
  
  • tissues move from aerobic respiration to anerobic respiration
  • produce lactic acid and have tingling/numbness in local area

Question 28

Metarterioles

• function
• layers

Answer 28

• Smallest arteriole branch
• regulate blood flow to capillaries
• Tunica intima
  
  • only endothelium
• Tunica Media
  
  • incomplete layer of smooth muscle
  • precapillary sphincter
• Tunica Adventitia
  
  • Indistinguishable

Question 29

Capillary: Types

Answer 29

• Continuous (somatic)
  
  • nonporous
  • Tightly bound together by zonula occludents
  • all types of muscle, brain, peripheral nerves, exocrine glands
• Fenestrated (visceral)
  
  • porous (limited size for transport)
  • where rapid exchange is required
    
    • kidney, intestines, endocrine glands
• Sinusoidal (discontinuous artery)
  
  • wide lumen
  • gaps b/w endothelial cells
  • abundant fenestrtions w/out diaphgram
  • partial or no basal lamina
  • found in hematopoietic organs
    
    • pulmonary
    • liver
  • phagocytes found on endothelial walls

Question 30

Venules

Answer 30

• Receives blood from capillaries
• some gas exchange
• larger lumen compared to arterioles
• Tunica intima
  
  • endothelium
  • no valves
• Tunica Media
  
  • very thin
  • few smooth muscle layers
• Tunica Adventitia
  
  • thickest tunic
  • mostly collagen

Question 31

Capillary: layers

Answer 31

• No tunic Adventitia or Tunic media
• ONLY tunic Intima

Question 32

Comparison of Structure of Blood vessels:

tunic Intima, Media, Externa/Adventitia

Typical vs arteries vs, veins, vs capillaries

Answer 32

• Typical:
  
  • Tunica intima:
    
    • endothelium
  • Tunica Media:
    
    • smooth muscle
    • elastic fibers
  • Tunica adventitia
    
    • collagen fibers
• Arteries
  
  • Tunica intima
    
    • smooth lining
  • Tunica Media
    
    • thicker than veins
  • Tunica Adventitia
    
    • thicker in veins
    • thinner than tunica media
• Veins:
  
  • Tunica intima
    
    • smooth lining w/valves
  • Tunica media
    
    • thinner than arteries
  • Tunica Adventitia
    
    • thiner than arteries
    • thicker than tunica media
• Capillaries
  
  • Tunica Initia ONLY
    
    • gas exchange