Circulatory System Flashcards
Functions of the Circulatory System (4)
1) Carries blood from heart to body & back
2) Allows nutrient, waste & gas exchange with tissues.
3) Transport other substances (hormones, enzymes, etc.) through body
4) Regulates blood pressure & blood flow to the tissues
Circulatory System consists of what 2 systems
Cardiovascular & Lymphatic systems
How does blood flow from the heart?
Through elastic arteries, muscular arteries, arterioles, to capillaries.
Cardiovascular systems consists of….
Blood Vessels & the Heart
How does blood flow to the heart?
From capillaries through venules, small veins, & large veins.
What are the 3 layers of a blood vessel?
1) Tunica externa
2) Tunica media
3) Tunica interna
Tunica Interna (3)
1) Innermost layer of blood vessels
2) Direct contact with LUMEN
3) Consists of Endothelium (simple squamous ET) & a layer of elastic CT (connective tissue)
Tunica Media (3)
1) Middle layer of blood vessels
2) Thick
3) Consists of smooth muscle & elastic fibers
Tunica Externa (3)
1) Outermost layer of blood vessel
2) Extremely strong & elastic
3) Contains large amounts of Protein fibers
What are the 3 types of Arteries?
1) Large elastic arteries
2) Muscular Arteries
3) Arterioles
Function of Arteries (3)
1) Carry blood from heart to body (directly to arterioles)
2) LOW-RESISTANCE CONDUITS- they ease blood flow and allow for constant pressure
3) PRESSURE RESERVOIRS- Stretching and recoiling help maintain pressure created,during systole (heart contraction)
Aneurysm
Blow out blister within an artery
Vasoconstriction
-Contractility (constriction of blood vessels by small smalls in their walls)
Vasodilation
- Elasticity (dilation of blood vessels to allow more blood flow and lower blood pressure)
Large Elastic (conducting) Arteries (4)
1) Thin-walled & large in diameter
2) It’s Tunica Media layer has MANY elastic fibers & FEW smooth muscle
3) Ones closest to heart
4) FUNCTIONS AS A PRESSURE BUFFER (expands during systole)
Muscular (distributing) Arteries (4)
1) Thick-walled & small in diameter
2) It’s Tunica Media layer has MANY smooth muscle & FEW elastic fibers
3) Adjust blood volume via vasoconstriction & dilation
4) EX: Intercostal, Brachial, Radial, & Axillary
Arterioles (2)
1) Small narrow branches of arteries
2) It’s Tunica Media has smooth muscle fibers & FEW elastic fibers
Endothelium
Simple squamous epithelium that lines the entire circulatory sysem
Capillaries (properties- 7)
1) Most common type of blood vessel 2) Thinnest walls
3) Consist only of endothelium
4) Surrounded by Externa (loose connective tissue) that contains Pericapillary cells
5) Do not exist individually but form branching networks
6) Low BP inside
7) Allows transport/exchange of materials with blood
3 Types of Capillaries
1) Continuous Capillaries
2) Fenestrated Capillaries
3) Sinusoidal Capillaries
Continuous Capillaries (2)
1) Have no gaps between the endothelial cells (less permeable to large molecules)
2) located in muscle & nervous tissue
Fenestrated Capillaries (2)
1) Have pores called Fenestrae that extend completely though the cell (highly permeable)
2) Located in intestinal villie, ciliary processes of eye, & choroid plexus of CNS
Sinusoidal Capillaries (2)
1) large-diameter capillaries with large fenestrate
2) located liver & endocrine glands
How do materials pass through capillaries? (3)
1) between endothelial cells
2) through fenestrae
3) through plasma membrane
How does blood travel though capillary networks? (2)
1) Arterioles supply blood through metarterioles –> thoroughfare channel –> venule
2) Blood flow is regulated by precapillary sphincters
Arteriovenous Anastomoses
Specialized vascular connections that allow blood to flow directly from arterioles to small veins without passing through capillaries
Veins vs. Arteries (4)
1) Veins carry deoxygenated blood to the heart, arteries carry oxygenated blood away
2) Veins are thinner
3) Vein walls contain less elastic tissue & smooth muscle fibers
4) Veins closer to the heart have thicker walls and are greater in diameter
Veins- Structure (3)
1) Smaller than arteries
2) Thinner, weaker, less elastic walls
3) Contain valves that prevent blood backflow
Veins- Function & Important Property (2)
1) Carry blood from venules toward the heart
2) BP is low within veins
Valves (3)
1) Prevents blood backflow
2) In veins that are larger than 2mm in diameter (many medium veins)
3) More valves in lower limb veins than upper limb
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Venules (3)
1) Narrow vessels similar to veins
2) Carry blood from capillaries to veins
3) Walls consist of 3 tunics when to close to veins BUT no tunica media when close to capillaries
Pulmonary Circulation
Circulation of blood between HEART & LUNGS
Pulmonary Arteries vs. Pulmonary Veins (2)
1) Arteries carry deoxygenated blood from the heart to the lungs
2) Veins carry oxygenated blood from the lungs to the heart
Systemic Circulation
Circulation of blood between the HEART & BODY TISSUES
Veins of Systemic Circulatory System (7)
1) Superior Vena Cava
2) Inferior Vena Cava
3) Common Iliac Vein
4) Femoral Vein
5) Internal Jugular Vein
6) Renal Vein
7) Subclavian Vein
Arteries of Systemic Circulatory System (8)
1) Aorta
2) Brachial Artery
3) Common Carotid Artery
4) Common Iliac Artery
5) Femoral Artery
6) Radial Artery
7) Renal Artery
8) Subclavian Artery
How many pulmonary veins empty blood into the left atrium?
4
