heart structure

what are the three layers of the heart? what are their functions ?

1. epicardium: protect the heart, secrete lubricating serous fluid

2. myocardium: muscular layer, contracts to pump

3. endocardium: inner most layer line the chambers and valves

what tissue lines the entire circulatory system

endothelium

describe the endothelium. the cells that its made of, structure, its functions, and what contributes to those unctions

1. cells that its made of: single layer of squamous endothelial cells

2. functions:

   • semipermeable membrane between blood and surrounding tissues (because of tight junctions that connect cells)

   • reduces friction between blood and vessel walls (because its smooth)

   • causes vasoconstriction(releases peptides called endothelins which causes smooth muscle in blood vessel to contract)

   • inhibit coagulation of blood (release chemicals) (exception: if endothelium is damaged chemicals are secreted to promote clotting)

write out the general route of blood from deoxygenated to oxygenated

1. vena cava

2. right atrium

3. tricuspid valve

4. right ventricle

5. pulmonary ventricle

6. pulmonary artery

7. lungs

8. pulmonary veins

9. left atrium

10. mitral valve

11. left ventricle

12. aortic valve

13. aorta

what is the optima temperature for metabolic process

37 degrees farenheit

describe relationship between vasodilation and temperature

smooth muscles relax and arteriole dilate

more blood flows through capillary beds

increases heat loss to surroundings via radiation

describe relationship between vasoconstriction and temperature

smooth muscles contract

reduces amount of blood that flows near body surface

minimal heat loss to surroundings