Cardiovascular System: Vessels & Circulation

Flashcards covering the cardiovascular system, vessels, and circulation, including blood vessel structure and function.

Arteries

Convey blood from the heart to capillaries

Capillaries

Microscopic porous blood vessels where exchange occurs between blood and tissues

Veins

Transport blood from capillaries back to the heart

Lumen

Space inside of a vessel

Tunica Intima

Innermost layer of a vessel wall composed of endothelium

Tunica Media

Middle layer of a vessel wall, containing smooth muscle cells and elastic fibers

Tunica Externa

Outermost layer of a vessel wall, composed of areolar connective tissue

Vasoconstriction

Narrows the lumen of a vessel

Vasodilation

Widens the lumen of a vessel

Vasa Vasorum

Small arteries required to supply very large vessels

Elastic (Conducting) Arteries

Largest type of arteries; conduct blood from the heart to muscular arteries

Muscular (Distributing) Arteries

Medium arteries that distribute blood to specific body regions

Arterioles

Smallest arteries that regulate systemic blood pressure and blood flow

Atherosclerosis

Progressive disease of elastic and muscular arteries involving atheroma formation

Aneurysm

Part of arterial wall thins and balloons out, prone to rupture

Capillaries

Small vessels connecting arterioles to venules, facilitating exchange

Continuous Capillaries

Endothelial cells form a continuous lining with tight junctions and intercellular clefts

Fenestrated Capillaries

Endothelial cells have fenestrations (pores) for fluid transport

Sinusoids (Discontinuous Capillaries)

Endothelial cells form an incomplete lining with large gaps for transport of large substances

Capillary Beds

Groups of capillaries functioning together, fed by a metarteriole

Precapillary Sphincter

Smooth muscle ring at true capillary origin that regulates blood flow

Perfusion

Amount of blood entering capillaries per unit time per gram of tissue

Venules

Smallest veins; merge to form larger veins

Valves (in veins)

Prevent blood from pooling in the limbs; ensure flow toward heart

Blood Reservoirs

Systemic veins function as this, holding a large percentage of the body's blood at rest

Simple Pathway

One major artery delivers blood to an organ or region

Arterial Anastomosis

Two or more arteries converge to supply the same region

Arteriovenous Anastomosis (Shunt)

Transports blood from an artery directly to a vein

Portal System

Two capillary beds in sequence (artery, capillary bed, portal vein, capillary bed, vein)

Total Cross-Sectional Area

Sum of diameters of all vessels of a certain type

Diffusion

Substances move from high to low concentration between blood and tissues

Vesicular Transport

Endothelial cells use pinocytosis & exocytosis to transport substances

Filtration

Fluid moves out of blood

Reabsorption

Fluid moves back into blood

Blood hydrostatic pressure (HPb)

Force exerted per unit area by blood on a vessel wall

Blood colloid osmotic pressure (COPb)

Draws fluid into blood due to blood proteins

Net Filtration Pressure (NFP)

Difference between net hydrostatic pressure & net colloid osmotic pressure

Lymphatic System

Picks up excess fluid not reabsorbed at venous capillary end

Degree of Vascularization

Extent of vessels in a tissue

Angiogenesis

Formation of new blood vessels

Myogenic Response

Smooth muscle in blood vessel wall keeps local flow relatively constant

Vasoactive Chemicals

Chemicals that alter blood flow

Autoregulation

Tissue controls local blood flow

Reactive Hyperemia

Increase in blood flow after it is temporarily disrupted

Total Blood Flow

Amount of blood transported through vasculature per unit time

Blood Pressure

Force of blood against vessel wall

Blood Pressure Gradient

Change in pressure from one end of vessel to the other

Systolic Pressure

Occurs when ventricle contracts (systole)

Diastolic pressure

Occurs when ventricles relax (diastole)

Pulse Pressure

Pressure in arteries added by heart contraction

Mean Arterial Pressure (MAP)

Average arterial blood pressure across entire cardiac cycle

Pulse

Throbbing of arterial wall

Cerebral Edema

Excess interstitial fluid in the brain

Pressure gradient, skeletal muscle pump, & respiratory pump

Venous return of blood to the heart depends on these three

Skeletal muscle pump

Assists venous return from limbs

Respiratory pump

Assists venous return in the thorax

Deep Vein Thrombosis

Clot (thrombosis) in a vein

Varicose Veins

Dilated and tortuous veins

Resistance

Friction blood encounters

Peripheral Resistance

The resistance of blood in blood vessels

Resistance

Longer vessels create more of this

Resistance

Smaller radius creates more of this

Resistance

The friction blood encounters

Blood Pressure

Autonomic reflexes regulate this short-term

Baroreceptors

Located in tunica externa of aortic arch & carotid sinuses

Chemoreceptors

Located in aortic & carotid bodies

Renin-angiotensin system

Regulates blood pressure and hormone-regulated

Aldosterone

Helps maintain blood volume & pressure (hormone)

Antidiuretic Hormone (ADH)

Helps maintain & elevate blood pressure (hormone)

Atrial Natriuretic Peptide

Decreases blood pressure (hormone)

Hypertension

Chronically elevated blood pressure

Hypotension

Chronically low blood pressure

Orthostatic Hypotension

Drop in blood pressure after sudden standing

Pulmonary Circulation

Deoxygenated blood to lungs

Coronary Arteries

Supply heart wall to arteries

Superior Vena Cava, Inferior Vena Cava, Coronary Sinus

Returns blood to right atrium

Common Carotid Arteries

Most blood supplied to head and neck

Vertebral Arteries

Foramina of cervical vertebrae

Cerebral Arterial Circle (Circle of Willis)

Important arterial anastomosis around sella turcica

Internal Thoracic Artery

Anterior thoracic wall & mammary gland

Lumbar Arteries

Posterolateral abdominal wall

Median Sacral Artery

Sacrum & coccyx

Internal Jugular Vein

Drains cranial cavity

Azygos System of Veins

Receives blood from lumbar & posterior intercostal veins

Bronchial Arteries

Bronchi & bronchioles

Abdominal Aorta

Comes from arteries

Celiac Trunk, Superior Mesenteric Artery, Inferior Mesenteric Artery

Three arteries

Splenic Vein, Inferior Mesenteric Vein, Superior Mesenteric Vein

Three main veins drain into

Internal & External Iliac Arteries

Right & left arteries divide into

Subclavian Artery & External Iliac Artery

One main artery receives blood from

Axillary Artery

Axilla, chest wall, shoulder, humerus

Radial & Ulnar Arteries

Deep vein and superficial palmar

Brachial and divisions

Divisions of arteries

Great & small Saphenous veins

Originates in medial ankle and ankle

Fetal & newborn vessels

Differences between vessels

Fetal Vessels pressure in birth

Pulmonary of 15 pressure

Oxygenated blood

Enters enters fetus

Ductus venosus

Goes into venous

Ligament of the liver

Becomes liver

Ligamentum arteriosum

Fibrous of arteries