The Vascular System Part 1 Flashcards
definition of BLOOD VESSELS
the DELIVERY SYSTEM of DYNAMIC STRUCTURES that BEGINS and ENDS at the HEART
definition of ARTERIES
blood vessels that carry BLOOD AWAY FROM THE HEART
- carries OXYGENATED BLOOD (with the EXCEPTION of PULMONARY and UMBILICAL VESSELS)
definition of ARTERIOLES
smaller ARTERIES that ENTER our TISSUE
- begin to BRANCH OFF to make CAPILLARIES and begins to SUPPLY TISSUE CELLS–serves cellular needs
definition of VENULES
small VEINS that come from GROUPS OF CAPILLARIES
- collects blood from the CAPILLARY
definition of VEINS
blood vessels that carry BLOOD BACK to the HEART
- carries DEOXYGENATED BLOOD
describe the HISTOLOGICAL STRUCTURE of BLOOD VESSEL WALLS/ what are the 3 TUNICS of our BLOOD VESSEL WALLS?
WALL LAYERS/TUNICS:
- TUNICA INTIMA
- TUNICA MEDIA
- TUNICA EXTERNA
describe the TUNICA INTIMA
- includes the ENDOTHELIUM
- begins to LINE THE LUMEN–moves simultaneously to the ENDOCARDIUM
- has an INTERNAL ELASTIC TISSUE
- has the SUBENDOTHELIAL LAYER–has CONNECTIVE TISSUE
describe the TUNICA MEDIA
- contains SMOOTH MUSCLE and ELASTIC FIBERS/ELASTIN –makes our vessels STRETCHY
- controls VASOCONSTRICTION and VASODILATION begins to INFLUENCE B
- has an EXTERNAL ELASTIC MEMBRANE
describe TUNICA EXTERNA
- composed of ELASTIC CONNECTIVE TISSUE
- contains COLLAGEN FIBERS–very important for ANCHORING and PROTECTION
- contains LYMPHATIC VESSELS
- contains the VASO VASORUM
describe the VASO VASORUM
- often is a PART OF ALL LARGE VESSELS
- begins to NOURISH EXTERNAL VESSELS–helps with SUPPLYING NUTRIENTS and REMOVES WASTE
describe the LUMEN
the area where blood passes through
- helps with the transportation of blood; a certain CAVITY
what are the THREE DIVISIONS of ARTERIES?
- have THREE DIVISIONS for ARTERIES–all based on SIZE AND FUNCTION
- ELASTIC ARTERIES
- MUSCULAR ARTERIES
- ARTERIOLES
describe ELASTIC ARTERIES/CONDUCTING ARTERIES
- thick walled with LARGE LOW-RESISTANCE LUMEN
- often known as CONDUCTING ARTERIES–ex. the AORTA and other MAJOR BRANCHES
- important for CONDUCTING BLOOD–transports from HEART to MEDIUM-SIZED VESSELS
describe the SIGNIFICANCE of ELASTIN
- protein that is found in ALL THREE TUNICS (most in TUNICA MEDIA)
- contains SUBSTANTIAL SMOOTH MUSCLE (this is INACTIVE in VASOCONSTRICTION)
- acts as specific PRESSURE RESERVOIRS
- begins to ABSORB PRESSURE for minimization as blood MOVES DOWNSTREAM
describe the MUSCULAR ARTERIES
- rose from origin of ELASTIC ARTERIES
- also known as DISTRIBUTING ARTERIES–begins to DELIVER BLOOD TO BODY ORGANS
- has a broad range of DIAMETER; can be size of as pinky to a pencil
- they have the THICKEST TUNICA MEDIA–sandwiched between ELASTIC MEMBRANES
- have greater amount of ELASTIC TISSUE
- ACTIVE IN VASOCONSTRICTION–helps with MAINTAINING VESSEL PRESSURE
describe ARTERIOLES
- the SMALLEST OF ALL ARTERIES
- known as RESISTANCE ARTERIES–changing of DIAMETERS begins to have CHANGES OF RESISTANCE to BLOOD FLOW
- have a controlled flow into CAPILLARY BEDS (via VASO DILATION) and the VASOCONSTRICTION of SMOOTH MUSCLE
what is the DIFFERENCE between LARGE and SMALL ARTERIOLES? what is the METARTERIOLE?
LARGE ARTERIOLES:
- contains all THREE TUNICS
SMALLER ARTERIOLES:
- contains only a SINGLE LAYER OF SMOOTH MUSCLE that begins to SURROUND ENDOTHELIAL CELLS
METARTERIOLE:
- the VERY END of the CAPILLARIES
- the GAS EXCHANGE SITE
definition of CAPILLARIES
- provides access to ALMOST EVERY CELL and ALMOST ALL TISSUES
- exceptions: CARTILAGE, EPITHELIA, CORNEA, and EYE LENS
what are PERICYTES?
spider-shaped STEM CELLS that help
- stabilizes CAPILLARY CELLS
- controls PERMEABILITY
- plays a role in VESSEL REPAIR
what is the FUNCTION OF CAPILLARIES?
- helps with the exchange of GASES + NUTRIENTS + WASTES + HORMONES between blood and interstitial fluid–known as VASOMOTION (just means INTERMITTENT CONTRACTION and RELAXATION)
- released by ENDOTHELIAL CELLS–NITRIC OXIDE
what are our 3 TYPES OF CAPILLARIES?
- CONTINUOUS CAPILLARIES
- FENESTRATED CAPILLARIES
- SINUSOID CAPILLARIES
describe CONTINUOUS CAPILLARIES
- found ALL OVER THE BODY (within SKIN, MUSCLES, LUNGS, and CNS)
- quite UNIQUE to see in BRAIN–have own BRAIN CAPILLARY ENDOTHELIAL CELLS with TIGHT JUNCTIONS in formation of BLOOD BRAIN BARRIER
- often have associated PERICYTES and PINOCYTOTIC VESICLES
describe FENESTRATED CAPILLARIES
- has typical LARGE FENESTRATIONS or aka PORES that aid in INCREASING PERMEABILITY
- often seen in AREAS OF ACTIVE FILTRATION (ex. the KIDNEYS), areas of ACTIVE ABSORPTION (ex. the SMALL INTEST), and AREAS OF ACTIVE SECRETION (ex. the ENDOCRINE GLANDS)
- can also be seen in the DIGESTIVE TRACT–have a greater number of FENESTRATIONS (due to ACTIVE ABSORPTION OF NUTRIENTS)
- FENESTRATIONS have a THIN DIAPHRAGM made up of GLYCOPROTEINS
describe SINUSOID CAPILLARIES
- often seen in LIVER, BONE MARROW, SPLEEN, and the ADRENAL MEDULLA
- have LARGER INTRACELLULAR CLEFTS and FEW TIGHT JUNCTIONS
- larger clefts allow for LARGER MOLECULES and CELLS to PASS THROUGH–slower process of blood entering
- have INCOMPLETE BASEMENT MEMBRANES
- are IRREGULARLY SHAPED and have LARGE LUMENS
definition of CAPILLARY BED
- the NETWORK OF CAPILLARIES within a TISSUE
definition of PRECAPILLARY SPHINCTERS
sphincters that allow for BLOOD FLOW through TRUE CAPILLARIES–where GAS EXCHANGE IS HAPPENING)
- can OPEN AND CLOSE in regulation of BLOOD FLOW
definition of THOROUGHFARE CHANNEL
- gets blood from TRUE CAPILLARIES–connects the METAARTERIOLE to a VENULE
- all regulated by LOCAL CHEMICAL CONDITIONS and VASOMOTOR NERVES
what is another name for VEINS?
also known as CAPACITANCE VESSELS (blood reservoirs)
- responsible for containing of around 65% - 70% of BLOOD SUPPLY
- have specific VALVES–helps to PREVENT BACKFLOW
- often seen in LEGS and LOWER EXTREMITIES
describe the CLINICAL CONDITION of VARICOSE VEINS
specific LEAFLETS OF VALVES–can no longer meet properly:
this is known as VALVULAR INCOMPETETENCE
- allows BLOOD TO FLOW BACKWARDS & enlarge even more
- also known as SUPERFICIAL VEINS OF LEGS (high pressure while standing)
describe the clinical condition of DVT (Deep Venous Thrombosis)
the formation of a BLOOD CLOT (THROMBUS) within a DEEP VEIN
- type of MEDICAL EMERGENCY
symptoms:
- PAIN
- SWELLING
- REDNESS/WARMNESS
what are the PORTIONS OF BLOOD DISTRIBUTION?
- SYSTEMIC VEINS & VENULES (60%)
- SYSTEMIC ARTERIES + ARTERIOLES (15%)
- PULMONARY BLOOD VESSELS (12%)
- HEART (8%)
- CAPILLARIES (5%)
**DURING REST–the largest portion of blood is in the SYSTEMIC VEINS + VENULES
definition of BLOOD FLOW
the VOLUME OF BLOOD FLOWING through the VESSEL, ORGAN, or the ENTIRE CIRCULATION in the given period
- measured as mL/min
- equivalent to CARDIAC OUTPUT (CO) for the ENTIRE VASCULAR SYSTEM
- relatively constant AT REST
what are the specific CALCULATIONS to calculate BLOOD FLOW
HR x SV (around 5.5 mL)
EDV - ESV = SV
- the HIGHER THE BP, the GREATER THE BLOOD FLOW
definition of RESISTANCE (PERIPHERAL RESISTANCE)
the OPPOSITION to blood flow due to the FRICTION BETWEEN BLOOD and the WALLS OF THE BLOOD VESSELS
what are the RESISTANCE DETERMINANTS?
- BLOOD VESSEL DIAMETER
(the GREATEST INFLUENCER of RESISTANCE) - BLOOD VISCOSITY
(the STICKINESS or THICKNESS OF BLOOD) - TOTAL BLOOD VESSEL LENGTH
(longer the vessel–the greater the RESISTANCE)
definition of BLOOD PRESSURE (BP)
the contraction of the VENTRICLES TO generate BP
- the observation of HIGHER PRESSURE AREAS to LOWER PRESSURE AREAS
what are the BLOOD PRESSURE DETERMINANTS?
- CO
- BLOOD VOLUME
- VASCULAR RESISTANCE
- the HIGHER THE BP, the GREATER THE BLOOD FLOW
- need cooperation between the HEART, BV, and the KIDNEYS
describe the RELATIONSHIPS between BLOOD FLOW and BP + RESISTANCE
- BF is DIRECTLY PROPORTIONAL to BP
- if (BP) INCREASES, BF will INCREASE
- BF is INVERSELY PROPORTIONAL TO R
- if (R) INCREASES, BF will DECREASE
**RESISTANCE is more significant in terms of influencing local blood flow–can be changed through ALTERING BV DIAMETER
definitions of SYSTOLIC and DIASTOLIC PRESSURES
SYSTOLIC PRESSURE:
- the pressure exerted in the AORTA (during VENTRICULAR CONTRACTION)
- where LV pumps blood into aorta–creation of KINETIC ENERGY that begins to STRETCH THE AORTA
- around avg. 120 mm Hg within normal adult
DIASTOLIC PRESSURE:
- the LOWEST LEVEL OF AORTIC PRESSURE when the HEART IS AT REST
- around avg. 80 mm Hg
definition of MEAN ARTERIAL PRESSURE (MAP)
- pressure that PROPELS BLOOD to the TISSUES
- the pulse pressure begins to PHASE OUT at the NEAR END of the ARTERIAL TREE
- FLOW IS NONPULSATILE (STEADY MAP PRESSURE)
describe CAPILLARY BLOOD PRESSURE, and what is often most desirable?
- most often desired would be LOW CAPILLARY PRESSURE
- if one has HIGH BP–can see RUPTURING in the FRAGILE and THIN-WALLED CAPILLARIES
- with more LOW PRESSURE FORCES: ensures proper filtration into the INTERSTITIAL SPACES (greater permeability)
what are the SPECIFIC FACTORS that AID IN VENOUS RETURN?
(VENOUS RETURN–often around 13 mm Hg, due to PERIPHERAL RESISTANCE)
- MUSCULAR PUMP
- the contraction of SKELETAL MUSCLES that begins to “MILK” the BLOOD BACK INTO THE HEART
- has VALVES to prevent BACKFLOW
- RESPIRATORY PUMP
- pressure that changes during BREATHING, moves the BLOOD TOWARD THE HEART (squeezes abdominal veins as thoracic veins expand)
- SYMPATHETIC VENOCONTRICTION
- sympathetic control; the SMOOTH MUSCLES CONSTRICT (pushes the BLOOD BACK TOWARDS THE HEART)
what relationship does MAP have with CO + PR?
each factor has a DIRECTLY PROPORTIONAL RELATIONSHIP
- changes in ONE VARIABLE can QUICKLY COMPENSATE for CHANGES in other variables
what are the SHORT-TERM/LONG-TERM MECHANISMS of regulating BP?
SHORT TERM MECHANISMS:
- oftern are responsible for regulating BV DIAMETER, HR, and CONTRACTILITY
- NEURAL (SHORT-TERM RAPID)
- HORMONAL (SHORT-TERM INTERMEDIATE)
LONG-TERM MECHANISMS
- often help to REGULATE BLOOD VOLUME
- RENAL (LONG-TERM)
describe NEURAL CONTROLS in terms as a SHORT-TERM MECHANISM
operates via REFLEX ARCS
- have the CARDIOVASCULAR CENTER of the MEDULLA
- BARORECEPTORS
- CHEMORECEPTORS
- HIGHER BRAIN CENTERS
describe the FUNCTION of the MEDULLA OBLONGATA
- contains a CARDIOVASCULAR CENTER
- helps with regulating HR, CONTRACTILITY, and BV DIAMETER
- usage of the SYMPATHETIC and PARASYMPATHETIC DIVISIONS of the ANS
describe BARORECEPTORS and their FUNCTION
- found in our CAROTIDS
- specific important PRESSURE-SENSITIVE SENSORY NEURONS that help with MONITORING the STRETCHING OF THE WALLS OF BV and the ATRIA
what happens if we have a DECREASE IN BP?
- ARTERIOLAR VASODILATION
- VENODILATION
- DECREASED CARDIAC OUTPUT (through the VAGUS NERVE)
describe CHEMORECEPTOR REFLEXES
reflexes that respond to CHEMICALS
- the AORTIC ARCH and the LARGE ARTERIES of the NECK begin to DETECT INCREASES in CO2 or any DROPS in pH/O2
INCREASED BP:
- the signaling of the CARDIOACCELEATORY CENTER to INCREASE CO
- the signaling of the VASOMOTOR CENTER to INCREASE VASOCONSTRICTION
describe the LONG TERM MECHANISM: RENAL REGULATION
KIDNEYS:
- plays with the ALTERING OF BLOOD VOLUME–regulated through the KIDNEYS
- has a DIRECT RENAL MECHANISM and INDIRECT RENAL MECHANISM
describe the DIRECT RENAL MECHANISM
- NO HORMONES USED
- MORE URINE REMOVED (reduced BP)
describe the INDIRECT RENAL MECHANISM
- works through the RENIN-ANGIOTENSIN-ALDOSTERONE
- have the release of ANGIOTENSINOGEN from the LIVER
- converted into ANGIOTENSIN II through ACE
ANGIOTENSIN II:
- helps to INCREASE BV–has greater amounts of ALDOSTERONE RELEASED)
- important for SODIUM REABSORPTION
describe HYPERTENSION and HYPOTENSION
HYPERTENSION:
- a SUSTAINED and ELEVATED ARTERIAL PRESSURE of 140.90 mm Hg or HIGHER
PREHYPERTENSION:
- the VALUES are ELEVATED; not in hypertensive range
- anything slightly over 120/80
- can be due to fever, physical exertion or upset / seen more in obese people
HYPOTENSION:
- LOW BLOOD PRESSURE; below 90/60 mm Hg
- not a typical concern; unless it causes INADEQUATE BLOOD FLOW to TISSUES
describe the DYNAMICS of CAPILLARY EXCHANGE.
have aspects of PRESSURE DYNAMICS TO CONSIDER
- BLOOD HYDROSTATIC PRESSURE (BHP)
- INTERSTITIAL FLUID HYDROSTATIC PRESSURE (IFHP)
- BLOOD COLLOID OSMOTIC PRESSURE (BCOP)
- INTERSTITIAL FLUID OSMOTIC PRESSURE (IFOP)
- NET FILTRATION PRESSURE (NFP)
definition of BHP - blood hydrostatic pressure
- the PROMOTION OF FILTRATION
- pressure generated from the PUMPING ACTION OF THE HEART
- often equivalent to what we know as BLOOD PRESSURE
- **WILL ALWAYS BE HIGHER ON THE ARTERIAL SIDE vs. the VENOUS SIDE
(pressure is PUSHING BLOOD OUT TO FILTRATE) - **BLOOD ALWAYS has a HIGHER OSMOTIC PRESSURE vs. INTERSTITIAL TISSUE
(OSMOTIC PRESSURE is ALWAYS CONSTANT IN THE CAPILLARIES)
definition of INTERSTITIAL FLUID HYDROSTATIC PRESSURE
- promotion of REABSORPTION
definition of BCOP - BLOOD COLLOID OSMOTIC PRESSURE
- promotion of REABSORPTION
- exerted by PROTEINS–ALBUMIN within the BLOOD, which pulls WATER into the CIRCULATORY SYS
- the OPPOSING FORCE to BHP
definition of IFOP - INTERSTITIAL FLUID OSMOTIC PRESSURE
- promotes FILTRATION
- forces FLUID AND SOLUTES to LEAVE THE CAPILLARIES to move into the IF
definition of NFP - NET FILTRATION PRESSURE
the balance of pressures BETWEEN THE ARTERIAL and VENOUS ENDS
describe the DYNAMICS of CAPILLARY EXCHANGE; ARTERIAL and VENOUS ENDS
ARTERIAL END:
- see that CAPILLARY PRESSURE is HIGHER THAN INTERSTITIAL FLUID PRESSURE
VENOUS END:
- CAPILLARY PLASMA COLLOID OSMOTIC PRESSURE is now LOWER THAN INTERSTITIAL FLUID PRESSURE
- causes REABSORPTION
what are the specific FORCES that DETERMINE FLUID MOVEMENT within the CAPILLARY MEMBRANE?
- CAPILLARY PRESSURE
- INTERSTITIAL FLUID PRESSURE
- PLASMA COLLOID OSMOTIC PRESSURE
- INTERSTITIAL FLUID COLLOID OSMOTIC PRESSURE
STARLING’S LAW OF THE CAPILLARIES
NFP = (BHP + IFOP) – (BCOP+ IFHP)
- this is where we have EQUILIBRIUM
definition of EDEMA
- an ABNORMAL INCREASE in the AMOUNT of INTERSTITIAL FLUID
- often caused due to an INCREASE IN OUTWARDS PRESSURE or DECREASE IN INWARD PRESSURE
describe the effects of various INCREASES and DECREASES in PRESSURE – affecting EDEMA
INCREASE: CAPILLARY HYDROSTATIC PRESSURE:
- acceleration of FLUID LOSS from BLOOD
- can have HIGH BV, incompetent VENOUS VALVES, and CONGESTIVE HEART FAILURE
INCREASE: INTERSTITIAL FLUID OSMOTIC PRESSURE:
- can result from INFLAMMATORY RESPONSE
DECREASE: CAPILLARY COLLOID OSMOTIC PRESSURE
- HINDERS FLUID RETURN to the BLOO
- can be caused by HYPOPROTEININEMIA
