Circulatory 🫀

• Epicardium - the outer layer of the heart, composed of simple squamous (mesothelium)
• Subepicardium – neurovascular structures with adipose; fibrocollagenous
• Subepicardium - Appears as a layer beneath the epicardium, containing visible blood vessels, nerves, and adipose tissue
• Myocardium – cardiac muscle tissue (myocytes) interconnected by intercalated discs
• Endocardium – inner lining of the heart chambers and valves, made of simple squamous with thinsubendothelium
• Pericardium – double-layered sac surrounding the heart, consisting of an outer parietal layer and an inner visceral layer
• Parietal pericardium – outermost layer of the pericardium, attaches to the diaphragm and sternum
• Subendocardium - fibrocollagenous, (+) Purkinje fibers
• Pericardium


  What is P?

  
• Purkinje Fibres are found in the subendocardium.
• Epicardium


  What layer of the heart is this?

  
• Heart (Subendocardium)


  Identify organ and what layer is SEp?

  
• Stiated cardiac muscle tissue 


  Identify type of tissue and specify appearance

  
• Heart, Subendocardium, Purkinje fiber


  Identify organ, layer and P?

  
• Endothelial cells, endocardium


  What are these cells called (E)? Identify layer

  
• Sinoatrial node - the heart's natural pacemaker, located in the right atrium
• Atrioventricular node - A node of the heart that sends electrical impulses to the atria and ventricles
• AV Bundle (Bundle of His) - A bundle of three arteries that form the right coronary artery
• AV Bundle - Extends from the AV node through the interventricular septum toward the apex of the heart.
• AV Bundle - Transmits electrical impulses rapidly from the AV node to the ventricles
• Purkinje fibers- extending from the bundle of His and branching throughout the ventricles.
• Purkinje fibers - contractile fibers that are responsible for the contraction of the ventricles
• Elastic artery, Aorta


  Identify type of artery? what organ?

  
• Muscular artery , smooth muscle fibers 


  Identify type of artery,composed of mostly?

  
• Layers of muscular artery:

  • Internal elastic lamina
  • Tunica intima
  • Tunica media
  • External elastic lamina
• Arterioles


  Identify what artery?

  
• Atheromatous aorta


  identify

  
• Normal aorta


  Identify

  
• Continouos capillary

  Are the least permeable and most common; have tight, occluding junctions sealing the intercellular clefts

  between all the endothelial cells to produce minimal fluid leakage.

  ● Often have associated pericytes

  ● All molecules are exchanged across the endothelium by diffusion or transcytosis
• → Skin

  → Skeletal Muscles

  → Adipose tissue

  → Exocrine glands

  → Respiratory organs (i.e., lungs)

  → CNS


  Where is this capillary found?

  
• → Endocrine organs

  → Small intestine

  → Kidney glomeruli

  → Choroid plexus in the brain ventricles


  Where else can we see this capillary?

  
• Fenestrated capillary

  ● Found in some tissues where there is extensive molecular exchange with the blood.

  ● Occurs in areas of active filtration (e.g., kidney) or absorption (e.g., small intestine) and areas of hormone secretion.
• Sinuosoidal capillary

  • Aka, discontinuous capillaries, are the most permeable and occur in limited locations.
  • Location:
  • Liver
  • → Bone marrow
  • → Spleen
  • → Adrenal medulla
• Sinusoidal


  Identify capillary

  
• Lymphatic vessels

  Found in all tissues EXCEPT:

  → CNS

  → Cartilage

  → Hone and bone marrow

  → Thymus

  → Placenta

  → Teeth