CHAPTER 31- Structure and Function of the Cardiovascular and Lymphatic System
A. Circulatory System
a. Right Heart Function
i. Pumps blood through lungs (pulmonary circulation)
ii. Delivers blood to the lungs for oxy
...
CHAPTER 31- Structure and Function of the Cardiovascular and Lymphatic System
A. Circulatory System
a. Right Heart Function
i. Pumps blood through lungs (pulmonary circulation)
ii. Delivers blood to the lungs for oxygenation
iii. Low pressure system
iv. Failures common in IV drug users and back up into lungs
b. Left Heart Function
i. Pumps oxygenated blood through the systemic circulation
ii. Delivers metabolic waste products to the lungs, kidneys and liver
iii. High Pressure system
iv. Failures back up into the periphery
B. The Heart
a. Structures that Direct Circulation Through the Heart
i. Function
1. Structural Support: includes heart wall and fibrous skeleton which
encloses and supports the heart and divides it into four chambers, the
valves that direct flow, and the great vessels that conduct blood to and
from the heart
2. Maintenance of heart cells: the vessels of coronary circulation- the
arteries and veins that serve the metabolic needs of all the heart cells
3. Stimulation and control of heart action: the nerves and specialized
muscle cells that direct rhythmic contraction and relaxation, propelling
blood throughout circulation
ii. Heart wall has 3 layers:
1. Pericardium- outermost, double walled membranous sac that encloses
the heart. A surface layer of mesothelium over a thin layer of connective
tissue. The visceral layer (epicardium) is the inner layer that folds back
on itself and becomes continuous with the parietal pericardium, allowing
the large vessels to enter and leave the heart without breaching the
pericardial layers. There is a pericardial cavity that separates the layer of
the pericardium with 10-30mL of fluid secreted by mesothelium cells to
lubricate and minimize friction
a. Prevents displacement of the heart during gravitational
acceleration or deceleration
b. A physical barrier that protects the heart against infection and
inflammation from the lungs and pleural space.
c. Contains pain receptors and mechanoreceptors that can elicit
reflex changes in blood pressure and heart rate
2. Myocardium- the thickest layer of the heart composed of cardiac muscle
and is anchored to the fibrous skeleton. Thickness varies from chamber
to chamber. Biggest concern for injury to this layer
3. Endocardium- the internal lining of the myocardium composed of
connective tissue and a layer of squamous cells. The endocardial lining
of the heart is continuous with the endothelium that lines all the arteries,
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