Anatomy: Cardiovascular and Lymphatic Systems
A. General Cardiovascular Concepts:
1. Homeostasis:
Body’s ability to change and survive during changing environment
Adapting to various changes and keeping a stable internal state
2. Components of the Cardiovascular System
i. heart
ii. blood vessels
iii. blood
3. Major Fluids of the Body
i. Blood (considered connective tissue):
1. Formed Elements:
Conn. Tissue; transport of nutrients, CO2, and other waste products
RBCs, WBCs, platelets (thrombocytes)
2. Blood Plasma (liquid portion)
a. 91% water
b. 7% protein
c. 2% other solutes
d. 1% electrolytes
ii. Interstitial Fluid:
when blood reaches extracellular environment
iii. Lymph:
fluid pushed into them from extracellular fluid; pushed into lymphatics and back to bloodstream
B. Describe the general organization and the flow of blood through the heart.
1. Location of the heart
Situated behind sternum located in the pericardium in medostinal cavity; left side is more
posterior; superior to diaphragm
2. Two Pumps
i. Pulmonary circuits
right side of the heart; deoxygenated blood to the lungs
ii. Systemic circuits
left side of heart; takes oxygenated blood and circulates it
3. Wall of the Heart
i. Epicardium- wall of heart; outer layer of visceral pericardium
ii. Myocardium- middle layer
iii. Endocardium- simple squamous
generates the force to move blood thru the body
4. Anatomy of the Heart
i. Great Vessels
1. transport blood to and from heart
2. blood from systemic venus return are the vena cavae; blood to right atrium of heart
3. pulmonary trunk; blood from right ventricle shunted to the lungs
4. aorta considered part of systemic circuit; blood from left ventricle and directs to body
ii. Chambers of the Heart
1. right atrium- receive blood
2. left atrium- receive blood
3. left ventricle- thick walled to propel blood thru body
4. right ventricle
iii. Fibrous Skeleton and Valves
1. tricuspid separates right atrium and ventricle
2. bicuspid valve separates the left atrium from the left ventricle
3. pulmonary semilunar valve separates right ventricle and pulmonary trunk
4. aortic semilunar valve separates left ventricle and ascending aorta
5. Pathway of blood flow through the heart
Blood enters from systemic circuit and enters right atrium; then thru tricuspid valve into the
right ventricle; goes thru semilunar valve and into pulmonary trunk into pulmonary arteries;
goes to lungs to get oxygen; blood return0 via pulmonary veinss through left atrium; goes into
left ventricle through bicuspid valve; goes through aortic semilunar valve and into ascending
aorta and then systemic circulation
C. Describe the structure of blood vessels.
1. Blood Vessel Tunics
i. tunica intima
endothelium; squamoun epithelium
ii. tunica media
circular layers of smooth muscles; constriction and dilation
iii. tunica externa
conn. tissue
2. Arteries
i. Large Elastic Arteries
rare; easily seen; aorta, pulm trunk and arteries
greater portion tunica media composed of elastic fibers
maintain blood pressure and send blood to smaller muscular arteris
ii. Medium Muscular Arteries
most prevalent in body; more muscular layers in media layer and less elastic fibers
branches are small arteries and arterioles
as they turn into smaller arterioles, lose the externa
iii. Small Arteries and Arterioles
--- Vasa Vasorium
Form network of small arteries located in tunica externa of large blood vessels
Large vessels have too big of cell walls to get any nutrients
3. Blood Vessel Innervation
i. Motor
vascontrict= increase blood pressure
vasodilate= decresase bp
ii. Sensory
1. barrow receptors= detect pressure changes inside blood vessels
aortic arch, carotid sinuses
2. chemoreceptors= detect chemicals and chemical balances
carotid bodies and aortic bodies
4. Veins
i. Large Veins
have all three layers in wall
smooth muscle in tunic media is decreased when compared to arteries
ii. Medium veins
decrease in tunica media apparent
has valves; tunica intima covering and collagen tissue flaps
one direction blood flow, move blood back to heart
skeletal muscle pump
iii. Venule
drain capillary beds; little tunica media
iv. Valves in Veins
see above
5. Capillaries (single layer simple squamous epithelium)
i. Capillary Bed Structure
smooth muscle circling the capillary entrance (sphincters)
ii. Types of capillaries
1. Continuous capillary
a. Most common
b. Epithithelial cells have tight junctions
c. Endothelium forms a continuous lining
2. Fenestrated capillary
a. forms a continuous lining/basement membrane
b. endothelial cells have small holes for passage
i. eye endocrine glands, kidney
3. Sinusoid
a. Discontinuous
b. Present in bone marrow, spleen liver
D. Describe the organization of a portal system
1. Portal Blood Flow
i. 2 capillary beds connect arteriole and venus system in tandem
ii. blood from heart goes into smaller and smaller arterioles until empty into capillaries; blood
now into venule and into vein; now goes into a second capillary bed and empties into another
venule, then a vein, and back to heart
2. Two portal systems in the body:
i. hepatic
digestive system and liver
ii. hypothalamic hypophyseal
delivers blood to pituitary gland
E. Define anastomosis and discuss the functional consequences of these vascular
connections.
1. What is an anatomosis?
a. Union of two blood vessels supplying the same region
i. If one channel blocked, there is a backup supply
2. Collateral Circulation
a. If main channel of blood is blocked, small channels enlarge to supply the area
3. Terminal (End) Arteries
a. Do not anastomose (functional ends do anastomose)
4. Vascular Shunt
a. Communication btwn arteries and veins without capillary beds
b. Sphincters shunt blood away cap beds and goes into thorofare channel
c. Distributes nutrients; capillaries open and close to regulate their areas
d. Absorption of nutrients into capillaries from GI is not constant
i. Only absorp when nutrients present
e. To keep people warm; shunt blood to surface to get rid of heat
i. Body temp regulation
F. Discuss the organization of the lymphatic system.
1. Functions of the Lymphatic System
i. lymph back to blood stream
ii. transport dietary lipids
iii. house lymphocytes used in immune respone
2. Structures of Lymphatic Tissue
i. lymph and channels
ii. lymph tissues
3. Lymphatic vessels
i. Lymphatic capillaries (plexuses)
first channels that lymph enters
blood ended pouches surrounded by simple squamous; very permeable
drain into small lymphatic vessels and drain into larger ones
as they get larger, become surrounded by 3 tunica layers
ii. Lymphatic vessels (lymphatics)
iii. Lymph Nodes (travels via afferent lymph vessel into the node; efferent sends out of node)
a. Function: traps foreign bodies, makes lymphocytes
iv. Lymphoid Tissue
spleen, thymus
4. Major Lymph Ducts (lymph diffusing back into bloodstream)
i. thoracic duct and cisterna chyli (drainage from digestive tract)
lymph from lower extremities, left head and neck, trunk, left upper extremities
ii. right lymphatic
right upper extremitiy, head, neck
5. Movement of lymph through the lymphatic system depends on
a. Filtration pressure
b. Contraction of muscles
c. Arterial pulsation
d. Respiratory movements
e. Smooth muscle contraction of lymphatic vessels