Lecture 20 9/25/23 Flashcards
What are the characteristics of the endocardium?
-simple squamous
-practically the same as endothelium
-lines the four chambers of heart
What is a hemangiosarcoma?
malignant tumor of the endothelial/endocardial cells of the heart
What are the characteristics of the heart valves?
-thin connective tissue core
-covered with endocardial cells
What are the two types of tissue in the myocardium?
-cardiac muscle
-perkinje fibers
What are the characteristics of cardiac muscle?
-striated
-branched
-intercalated discs
-central nuclei
What are the characteristics of perkinje fibers?
-lots of glycogen
-transmit electrical signals throughout heart
What is the cardiac skeleton?
four fibrous rings that provide structure for the heart/its chambers
Which animal has a cartilaginous cardiac skeleton?
cats
Which animal has an osseous cardiac skeleton?
cattle
What is the epicardium?
tissue on the outside of the heart
What are the characteristics of the epicardium?
-contains adipose tissue and coronary arteries/veins/nerves
-covered with mesothelium on the very outermost surface
How can endothelium and mesothelium be differentiated?
-knowing the location that you are looking at
-seeing adipose tissue typically indicates mesothelium
What are the characteristics of the pericardial sack?
-parietal pericardium
-thin collagen layer with mesothelium on both sides
-may contain adipose tissue
What is the function of the mesothelium?
producing pericardial and pleural fluids
Which fluid is on each side of the pericardial sac?
-pericardial fluid on the inside
-pleural fluid on the outside
What substances are typically contained within the lymphatic vessels?
-lymph fluid
-lymphocytes
What are the characteristics of lymphatic vessels?
-thin-walled
-have valves
-normally no erythrocytes
What are the characteristics of the lymphatic capillaries?
-blind-ended
-fluid flow towards heart only
-discontinuous endothelial cells and basement membrane
What is the function of the lymphatic capillaries?
to constantly pick up fluid, protein, and cells from the interstitium and return them to the circulatory system
Why do lymphatic vessels appear empty on microscopy?
the lymphatic fluid is clear and cannot be seen
How can lymphatic vessels and veins be distinguished microscopically?
-veins will contain blood and appear pink/red inside
-lymphatic vessels do not contain blood and will appear empty inside
Why are the lymphatic capillaries composed of discontinuous endothelial cells?
to allow cells to move through the capillaries
What do the lymphatic capillaries feed into?
larger lymphatic vessels
What are the characteristics of the larger lymphatic vessels?
-pass through lymph nodes
-empty into large veins near the heart
Which lymphatic vessel is the largest?
thoracic duct
Why is the lymphatic system important?
tumor cells will use the lymphatic vessels to metastasize
