0-1 Chapter 20 - blood vessels and circulation Flashcards
arteries
carry blood away from heart
veins
carry blood back to heart
capillaries
connect smallest arteries to veins
tunica interna
(tunica intima)
–lines the blood vessel and is exposed to blood
–endothelium –simple squamous epithelium overlying a basement membrane and a sparse layer of loose connective tissue
tunica interna
functions
•acts as a selectively permeable barrier
•secrete chemicals that stimulate dilation or constriction of the vessel
•normally repels blood cells and platelets that may adhere to it and form a clot
•when tissue around vessel is inflamed, the endothelial cells produce cell-adhesion molecules that induce leukocytes to adhere to the surface
–causes leukocytes to congregate in tissues where their defensive actions are needed
tunica media
–middle layer
–consists of smooth muscle, collagen, and elastic tissue
–strengthens vessel and prevents blood pressure from rupturing them
vasomotion
changes in diameter of the blood vessel brought about by smooth muscle
tunica externa
(tunica adventitia)
–outermost layer
–consists of loose connective tissue that often merges with that of neighboring blood vessels, nerves, or other organs
–anchors the vessel and provides passage for small nerves, lymphatic vessels
vasa vasorum
small vessels that supply blood to at least the outer half of the larger vessels
•blood from the lumen is thought to nourish the inner half of the vessel by diffusion
arteries
are sometimes called resistance vessels because they have relatively strong, resilient tissue structure that resists high blood pressure
conducting (elastic or large) arteries
- biggest arteries
- aorta, common carotid, subclavian, pulmonary trunk, and common iliac arteries
- have a layer of elastic tissue, internal elastic lamina, at the border between interna and media
- external elastic lamina at the border between media and externa
- expand during systole, recoil during diastole which lessens fluctuations in blood pressure
distributing (muscular or medium) arteries
- distributes blood to specific organs
- brachial, femoral, renal, and splenic arteries
- smooth muscle layers constitute three-fourths of wall thickness
aneurysm
weak point in an artery or the heart wall
–forms a thin-walled, bulging sac that pulsates with each heartbeat and may rupture at any time
dissecting aneurysm
blood accumulates between the tunics of the artery and separates them, usually because of degeneration of the tunica media
most common sites
abdominal aorta, renal arteries, and arterial circle at the base of the brain
results from
congenital weakness of the blood vessels or result of trauma or bacterial infections such as syphilis
•most common cause is atherosclerosis and hypertension
resistance (small) arteries
–arterioles –smallest arteries
•control amount of blood to various organs
–thicker tunica media in proportion to their lumen than large arteries and very little tunica externa
metarterioles
–short vessels that link arterioles to capillaries
–muscle cells form a precapillary sphincter about entrance to capillary
•constriction of these sphincters reduces or shuts off blood flow through their respective capillaries
•diverts blood to other tissues
Arterial Sense Organs
sensory structures in the walls of certain vessels that monitor blood pressure and chemistry
–transmit information to brainstem that serves to regulate heart rate, vasomotion, and respiration
carotid sinuses
baroreceptors (pressure sensors)
•in walls of internal carotid artery
•monitors blood pressure –signaling brainstem
–decreased heart rate and vessels dilation in response to high blood pressure
carotid bodies
chemoreceptors
•oval bodies near branch of common carotids
•monitor blood chemistry
•mainly transmit signals to the brainstem respiratory centers
•adjust respiratory rate to stabilize pH, CO2, and O2
aortic bodies
chemoreceptors
•one to three in walls of aortic arch
•same function as carotid bodies
capillaries
site where nutrients, wastes, and hormones pass between the blood and tissue fluid through the walls of the vessels (exchange vessels)
–the ‘business end’ of the cardiovascular system
–composed of endothelium and basal lamina
–absent or scarce in tendons, ligaments, epithelia, cornea and lens of the eye
three capillary types distinguished by
ease with which substances pass through their walls and by structural differences that account for their greater or lesser permeability
continuous capillaries
occur in most tissues
–endothelial cells have tight junctions forming a continuous tube with intercellular clefts
•allow passage of solutes such as glucose
–pericytes wrap around the capillaries and contain the same contractile protein as muscle
•contract and regulate blood flow
fenestrated capillaries
kidneys, small intestine
–organs that require rapid absorption or filtration
–endothelial cells riddled with holes called filtration pores (fenestrations)
•spanned by very thin glycoprotein layer
•allows passage of only small molecules
sinusoids (discontinuous capillaries)
liver, bone marrow, spleen
–irregular blood-filled spaces with large fenestrations
–allow proteins (albumin), clotting factors, and new blood cells to enter the circulation
Capillary Beds
capillaries organized into networks called capillary beds
–usually supplied by a single metarteriole
thoroughfare channel
metarteriole that continues through capillary bed to venule
precapillary sphincters
control which beds are well perfused
•three-fourths of the body’s capillaries are shut down at a given time
when sphincters open
•capillaries are well perfused with blood and engage in exchanges with the tissue fluid
when sphincters closed
•blood bypasses the capillaries
•flows through thoroughfare channel to venule
(skeletal muscles at rest)
Veins (Capacitance Vessels)
greater capacity for blood containment than arteries
•thinner walls, flaccid, less muscular and elastic tissue
•collapse when empty, expand easily
•have steady blood flow
•merge to form larger veins
•subjected to relatively low blood pressure
–remains 10 mm Hg with little fluctuation
postcapillary venules
smallest veins
–even more porous than capillaries so also exchange fluid with surrounding tissues
–tunica interna with a few fibroblasts and no muscle fibers
–most leukocytes emigrate from the bloodstream through venule walls
muscular venules
up to 1 mm in diameter
–1 or 2 layers of smooth muscle in tunica media
–have a thin tunica externa
medium veins
up to 10 mm in diameter
–thin tunica media and thick tunica externa
–tunica interna forms venous valves
–varicose veins result in part from the failure of these valves
–skeletal muscle pump propels venous blood back toward the heart
venous sinuses
–veins with especially thin walls, large lumens, and no smooth muscle
–dural venous sinus and coronary sinus of the heart
–not capable of vasomotion
large veins –larger than 10 mm
–some smooth muscle in all three tunics
–thin tunica media with moderate amount of smooth muscle
–tunica externa is thickest layer
•contains longitudinal bundles of smooth muscle
–venae cavae, pulmonary veins, internal jugular veins, and renal veins
Varicose Veins
blood pools in the lower legs in people who stand for long periods stretching the veins
–cusps of the valves pull apart in enlarged superficial veins further weakening vessels
–blood backflows and further distends the vessels, their walls grow weak and develop into varicose veins
hemorrhoids
varicose veins of the anal canal
Circulatory Routes
general
simplest and most common route
–heart to arteries to arterioles to capillaries to venules to veins
–passes through only one network of capillaries from the time it leaves the heart until the time it returns
Circulatory Routes
portal system
–blood flows through two consecutive capillary networks before returning to heart
•between hypothalamus and anterior pituitary
•in kidneys
•between intestines to liver
anastomosis
the point where two blood vessels merge
arteriovenous anastomosis
(shunt)
–artery flows directly into vein bypassing capillaries
venous anastomosis
–most common
–one vein empties directly into another
–reason vein blockage less serious than an arterial blockage
arterial anastomosis
–two arteries merge
–provides collateral (alternative) routes of blood supply to a tissue
–coronary circulation and around joints
Principles of Blood Flow
blood supply to a tissue can be expressed in terms of flow and perfusion
at rest, total flow is
quite constant, and is equal to the cardiac output (5.25 L/min)
•important for delivery of nutrients and oxygen, and removal of metabolic wastes
hemodynamics
physical principles of blood flow based on pressure and resistance
•F is proportional to P/R, (F = flow, P = difference in pressure, R = resistance to flow)
•the greater the pressure difference between two points, the greater the flow; the greater the resistance the less the flow
blood pressure
(bp) –the force that blood exerts against a vessel wall
measured at
brachial artery of arm using sphygmomanometer
two pressures are recorded
systolic pressure
diastolic pressure
systolic pressure
peak arterial BP taken during ventricular contraction (ventricular systole)
diastolic pressure
minimum arterial BP taken during ventricular relaxation (diastole) between heart beats
normal value, young adult:
120/75 mm Hg
pulse pressure
difference between systolic and diastolic pressure
–important measure of stress exerted on small arteries by pressure surges generated by the heart
mean arterial pressure (MAP
the mean pressure one would obtain by taking measurements at several intervals throughout the cardiac cycle
–diastolic pressure + (1/3 of pulse pressure)
–average blood pressure that most influences risk level for edema, fainting (syncope), atherosclerosis, kidney failure, and aneurysm
hypertension
high blood pressure
–chronic is resting BP > 140/90
–consequences
•can weaken small arteries and cause aneurysms
hypotension
chronic low resting BP
–caused by blood loss, dehydration, anemia
Blood Pressure
one of the body’s chief mechanisms in preventing excessive blood pressure is the ability of the arteries to stretch and recoil during the cardiac cycle
importance of arterial elasticity
–expansion and recoil maintains steady flow of blood throughout cardiac cycle, smoothes out pressure fluctuations and decreases stress on small arteries
•BP rises with age
–arteries less distensible and absorb less systolic force
BP determined by
cardiac output, blood volume and peripheral resistance
–resistance hinges on blood viscosity, vessel length, and vessel radius
peripheral resistance
the opposition to flow that blood encounters in vessels away from the heart
resistance hinges on three variables
blood viscosity “thickness”
vessel length
blood viscosity “thickness”
- RBC count and albumin concentration elevate viscosity the most
- decreased viscosity with anemia and hypoproteinemia speed flow
- increased viscosity with polycythemia and dehydration slow flow
vessel length
the farther liquid travels through a tube, the more cumulative friction it encounters
•pressure and flow decline with distance
vessel radius
most powerful influence over flow
•only significant way of controlling peripheral resistance.
vasomotion
change in vessel radius
–vasoconstriction-by muscular effort that results in smooth muscle contraction
–vasodilation -by relaxation of the smooth muscle
laminar flow
flows in layers, faster in center
arterioles can constrict to
1/3 of fully relaxed radius
–an increase of three times in the radius of a vessel results in eighty one times the flow
from aorta to capillaries, blood velocity (speed) decreases:
–farther from heart, the number of vessels and their total cross-sectional area becomes greater and greater
from capillaries to vena cava, flow increases again
–large amount of blood forced into smaller channels
–never regains velocity of large arteries
arterioles
are most significant point of control over peripheral resistance and flow
–on proximal side of capillary beds and best positioned to regulate flow into the capillaries
–outnumber any other type of artery, providing the most numerous control points
–more muscular in proportion to their diameter
•highly capable of vasomotion
arterioles produce
half of the total peripheral resistance
Regulation of BP and Flow
vasomotion is a quick and powerful way of altering blood pressure and flow
three ways of controlling vasomotion:
–local control
–neural control
–hormonal control
Local Control of BP and Flow
4 ways
autoregulation
vasoactive chemicals
reactive hyperemia
angiogenesis
autoregulation
the ability of tissues to regulate their own blood supply
–metabolic theory of autoregulation –if tissue is inadequately perfused,wastes accumulate stimulating vasodilation which increases perfusion
–bloodstream delivers oxygen and remove metabolites
–when wastes are removed, vessels constrict
vasoactive chemicals
substances secreted by platelets, endothelial cells, and perivascular tissue stimulate vasomotion
–histamine, bradykinin, and prostaglandins stimulate vasodilation
–endothelial cells secrete prostacyclin and nitric oxide (vasodilators) and endothelins (vasoconstrictor)
reactive hyperemia
if blood supply cut off then restored, flow increases above normal
angiogenesis
growth of new blood vessels
–occurs in regrowth of uterine lining, around coronary artery obstructions, in exercised muscle, and malignant tumors
–controlled by growth factors
Neural Control of Blood Vessels
vessels under remote control by the central and autonomic nervous systems
vasomotor center of medulla oblongata exerts
sympathetic control over blood vessels throughout the body
–stimulates most vessels to constrict, but dilates vessels in skeletal and cardiac muscle to meet demands of exercise
precapillary sphincters respond only to
to local and hormonal control due to lack of innervation
vasomotor center is the integrating center for three autonomic reflexes
baroreflexes
•chemoreflexes
•medullary ischemic reflex
baroreflex
an automatic, negative feedback response to changes in blood pressure
–increases in BP detected by carotid sinuses
–signals sent to brainstem by way of glossopharyngeal nerve
baroreflexes important in
short-term regulation of BP but not in cases of chronic hypertension
–adjustments for rapid changes in posture
chemoreflex
an automatic response to changes in blood chemistry
–especially pH, and concentrations of O2 and CO2
chemoreceptors
called aortic bodies and carotid bodies
–located in aortic arch, subclavian arteries, external carotid arteries
chemoreceptors called
aortic bodies and carotid bodies
–located in aortic arch, subclavian arteries, external carotid arteries
primary role:
adjust respiration to changes in blood chemistry
secondary role
vasomotion
–hypoxemia, hypercapnia, and acidosis stimulate chemoreceptors, acting through vasomotor center to cause widespread vasoconstriction, increasing BP, increasing lung perfusion and gas exchange
–also stimulate breathing
medullary ischemic reflex
automatic response to a drop in perfusion of the brain
–medulla oblongata monitors its own blood supply
–activates corrective reflexes when it senses ischemia (insufficient perfusion)
cardiac and vasomotor centers send sympathetic signals to
heart and blood vessels
–increases heart rate and contraction force
–causes widespread vasoconstriction
–raises BP and restores normal perfusion to the brain
Hormonal Control
hormones influence blood pressure
–some through their vasoactive effects
–some by regulating water balance
angiotensin II
potent vasoconstrictor
–raises blood pressure
aldosterone
–promotes Na+ and water retention by kidneys
–increases blood volume and pressure
atrial natriuretic peptide
increases urinary sodium excretion
–reduces blood volume and promotes vasodilation
–lowers blood pressure
ADH
promotes water retention and raises BP
–pathologically high concentrations -vasoconstrictor
epinephrine and norepinephrine
effects
–most blood vessels
•binds to B-adrenergic receptors -vasoconstriction
–skeletal and cardiac muscle blood vessels
•binds to B-adrenergic receptors -vasodilation
Two Purposes of Vasomotion
- general method of raising or lowering BP throughout the whole body
- method of rerouting blood from one region to another for perfusion of individual organs
localized vasoconstriction
–if a specific artery constricts, the pressure downstream drops, pressure upstream rises
–enables routing blood to different organs as needed
Blood Flow in Response to Needs
arterioles shift blood flow with changing priorities
Capillary Exchange
two way movement of fluid across capillary walls
–water, oxygen, glucose, amino acids, lipids, minerals, antibodies, hormones, wastes, carbon dioxide, ammonia
Capillary Exchange
importance
- the most important blood in the body is in the capillaries
* only through capillary walls are exchanges made between the blood and surrounding tissues
chemicals pass through the capillary wall by three routes
–through endothelial cell cytoplasm
–intercellular clefts between endothelial cells
–filtration pores (fenestrations) of the fenestrated capillaries
mechanisms involved
diffusion, transcytosis, filtration, and reabsorption
diffusion
is the most important form of capillary exchange
–glucose and oxygen being more concentrated in blood diffuse out of the blood
–carbon dioxide and other waste being more concentrated in tissue fluid diffuse into the blood
capillary diffusion can only occur if:
–the solute can permeate the plasma membranes of the endothelial cell, or
–find passages large enough to pass through
•filtration pores and intercellular clefts
lipid soluble substances
–steroid hormones, O2and CO2diffuse easily through plasma membranes
water soluble substances
–glucose and electrolytes must pass through filtration pores and intercellular clefts
Transcytosis
- endothelial cells pick up material on one side of the plasma membrane by pinocytosis or receptor-mediated endocytosis, transport vesicles across cell, and discharge material on other side by exocytosis
- important for fatty acids, albumin and some hormones (insulin)
Filtration
fluid filters out of the arterial end of the capillary and osmotically reenters at the venous end
–delivers materials to the cell and removes metabolic wastes
opposing forces
–blood hydrostatic pressure drives fluid out of capillary
•high on arterial end of capillary, low on venous end
–colloid osmotic pressure (COP) draws fluid into capillary
•results from plasma proteins (albumin)-more in blood
•oncotic pressure = net COP (blood COP -tissue COP)
Reabsorption
- capillaries reabsorb about 85% of the fluid they filter
* other 15% is absorbed by the lymphatic system and returned to the blood
hydrostatic pressure
physical force exerted against a surface by a liquid
•blood pressure is an example
Capillary Filtration
can happen at
- capillary filtration at arterial end
* capillary reabsorption at venous end
capillaries usually reabsorb most of the fluid they filter –exception:
–kidney capillaries in glomeruli do not reabsorb
–alveolar capillaries in lung absorb completely to keep fluid out of air spaces
edema
the accumulation of excess fluid in a tissue
–occurs when fluid filters into a tissue faster than it is absorbed
three primary causes
–increased capillary filtration
•kidney failure, histamine release, old age, poor venous return
–reduced capillary absorption
•hypoproteinemia, liver disease, dietary protein deficiency
–obstructed lymphatic drainage
•surgical removal of lymph nodes
Consequences of Edema
tissue necrosis
pulmonary edema
cerebral edema
severe edema or circulatory shock
tissue necrosis
–oxygen delivery and waste removal impaired
pulmonary edema
–suffocation threat
cerebral edema
–headaches, nausea, seizures, and coma
severe edema or circulatory shock
–excess fluid in tissue spaces causes low blood volume and low blood pressure
venous return
the flow of blood back to the heart
Mechanisms of Venous Return
pressure gradient gravity skeletal muscle pump in the limbs thoracic (respiratory) pump cardiac suction
pressure gradient
- blood pressure is the most important force in venous return
- 7-13 mm Hg venous pressure towards heart
- venules (12-18 mm Hg) to central venous pressure –point where the venae cavae enter the heart (~5 mm Hg)
gravity
gravity drains blood from head and neck
skeletal muscle pump in the limbs
contracting muscle squeezed out of the compressed part of the vein
thoracic (respiratory) pump
•inhalation -thoracic cavity expands and thoracic pressure decreases, abdominal pressure increases forcing blood upward
–central venous pressure fluctuates
•2mm Hg-inhalation, 6mm Hg-exhalation
•blood flows faster with inhalation
cardiac suction
of expanding atrial space
exercise increases venous return in many ways:
–heart beats faster, harder increasing CO and BP
–vessels of skeletal muscles,lungs,and heart dilate and increase flow
–increased respiratory rate, increased action of thoracic pump
–increased skeletal muscle pump
venous pooling occurs with
–venous pressure not enough to force blood upward
–with prolonged standing, CO may be low enough to cause dizziness
•prevented by tensing leg muscles, activate skeletal muscle pump
–jet pilots wear pressure suits
circulatory shock
any state in which cardiac output is insufficient to meet the body’s metabolic needs
cardiogenic shock
inadequate pumping of heart (MI)
low venous return (LVR)
cardiac output is low because too little blood is returning to the heart
hypovolemic shock
most common
-loss of blood volume: trauma, burns, dehydration
obstructed venous return shock
-tumor or aneurysm compresses a vein
venous pooling (vascular) shock
long periods of standing, sitting or widespread vasodilation
neurogenic shock
loss of vasomotor tone, vasodilation
–causes from emotional shock or brainstem injury
septic shock
–bacterial toxins trigger vasodilation and increased capillary permeability
anaphylactic shock
severe immune reaction to antigen, histamine release, generalized vasodilation, increased capillary permeability
Responses to Circulatory Shock
- compensated shock
* decompensated shock
compensated shock
several homeostatic mechanisms bring about spontaneous recovery
•decreased BP triggers baroreflex and production of angiotensin II, both counteract shock by stimulating vasoconstriction
•if person faints and falls to horizontal position, gravity restores blood flow to brain
–quicker if feet are raised
Decompensated shock
if compensating mechanisms inadequate, several life-threatening positive feedback loops occur
poor cardiac output results in
myocardial ischemia and infarction
•further weakens the heart and reduces output
slow circulation can lead to
disseminated intravascular coagulation
•vessels become congested with clotted blood
•venous return grows worse
ischemia and acidosis of brainstem
depresses vasomotor and cardiac centers
•loss of vasomotor tone, further dilation, and further drop in BP and cardiac output
damage to cardiac and brain tissue
may be too great to survive
Special Circulatory Routes-Brain
•total blood flow to the brain fluctuates less than that of any other organ (700 mL/min)
–seconds of deprivation causes loss of consciousness
–4-5 minutes causes irreversible brain damage
–blood flow can be shifted from one active brain region to another
brain regulates its own
blood flow to match changes in BP and chemistry
–cerebral arteries dilate as systemic BP drops, constrict as BP rises
–main chemical stimulus: pH
hypercapnia
CO2 levels increase in brain, pH decreases, triggers vasodilation
hypocapnia
raises pH, stimulates vasoconstriction
–occurs with hyperventilation, may lead to ischemia, dizziness ,and sometimes syncope
transient ischemic attacks
(TIAs ) –brief episodes of cerebral ischemia
–caused by spasms of diseased cerebral arteries
–dizziness, loss of vision, weakness, paralysis, headache or aphasia
–lasts from a moment to a few hours
–often early warning of impending stroke
stroke
cerebral vascular accident (CVA)
–sudden death of brain tissue caused by ischemia
•atherosclerosis, thrombosis, ruptured aneurysm
–effects range from unnoticeable to fatal
•blindness, paralysis, loss of sensation, loss of speech common
–recovery depends on surrounding neurons, collateral circulation
Special Circulatory Routes Skeletal Muscle
•highly variable flow depending on state of exertion
at rest:
–arterioles constrict
–most capillary beds shut down
–total flow about 1L/min
during exercise
–arterioles dilate in response to epinephrine and sympathetic nerves
–precapillary sphincters dilate due to muscle metabolites like lactic acid, CO2
–blood flow can increase 20 fold
•muscular contraction impedes flow
–isometric contraction causes fatigue faster than intermittent isotonic contractions
Special Circulatory Routes Lungs
low pulmonary blood pressure (25/10 mm Hg)
–flow slower, more time for gas exchange
–engaged in capillary fluid absorption
•oncotic pressure overrides hydrostatic pressure
•prevents fluid accumulation in alveolar walls and lumens
unique response to hypoxia
–pulmonary arteries constrict in diseased area
–redirects flow to better ventilated region
Pulmonary Circulation
•pulmonary trunk to pulmonary arteries to lungs
–lobar branches for each lobe (3 right, 2 left)
•pulmonary veins return to left atrium
–increased O2 and reduced CO2 levels
Pulmonary Capillaries Near Alveoli
- basketlike capillary beds surround alveoli
* exchange of gases with air and blood at alveoli
Major Systemic Arteries
•supplies oxygen and nutrients to all organs
Major Branches of Aorta
ascending aorta
aortic arch
descending aorta
ascending aorta
–right and left coronary arteries supply heart
aortic arch
–brachiocephalic
–left common carotid
–left subclavian
brachiocephalic
- right common carotid supplying right side of head
* right subclavian supplying right shoulder and upper limb
left common carotid
supplying left side of head
left subclavian
supplying shoulder and upper limb
descending aorta
–thoracic aorta above diaphragm
–abdominal aorta below diaphragm
Arteries of the Head and Neck
common carotid divides into internal and external carotids
–external carotid supplies most external head structures
Arterial Supply of Brain
paired vertebral arteries combine to form basilar artery on pons
Circle of Willis
on base of brain formed from anastomosis of basilar and internal carotid arteries
•supplies brain, internal ear and orbital structures
–anterior, middle and posterior cerebral
–superior, anterior and posterior cerebellar
Major Systemic Veins
deep veins run parallel to arteries while superficial veins have many anastomoses
Deep Veins of Head and Neck
- large, thin-walled dural sinuses form in between layers of dura mater
- drain blood from brain to internal jugular vein
Superficial Veins of Head and Neck
internal jugular vein
external jugular vein
subclavian vein
internal jugular vein
receives most of the blood from the brain
external jugular vein
branches of external jugular vein drain the external structures of the head
subclavian vein
upper limb is drained by subclavian vein
Arteries of the Thorax
•internal thoracic, anterior intercostal, and pericardiophrenic arise from subclavian artery
thoracic aorta supplies
viscera and body wall
–bronchial, esophageal, and mediastinal branches
–posterior intercostal and phrenic arteries
Major Branches of Abdominal Aorta
See diagram
Celiac Trunk Branches
branches of celiac trunk supply upper abdominal viscera -stomach, spleen, liver, and pancreas
Mesenteric Arteries
See diagram
Inferior Vena Cava and Branches
See diagram
Veins of Hepatic Portal System
drains nutrient rich blood from viscera (stomach, spleen and intestines) to liver so that blood sugar levels are maintained
Arteries of the Upper Limb
subclavian passes between clavicle and 1st rib
•vessel changes names as passes to different regions
–subclavian to axillary to brachial to radial and ulnar
–brachial used for BP and radialartery for pulse
Superficial and Deep Veins of Upper Limb
See diagram
Arteries of the Lower Limb
branches to the lower limb arise from external iliac branch of the common iliac artery
Superficial and Deep Veins of Lower Limb
See diagram
Arterial Pressure Points
some major arteries close to surface which allows for palpation for pulse and serve as pressure points to reduce arterial bleeding
hypertension
most common cardiovascular disease affecting about 30% of Americans over 50
•“the silent killer”
–major cause of heart failure, stroke, and kidney failure
•damages heart by increasing afterload
–myocardium enlarges until overstretched and inefficient
•renal arterioles thicken in response to stress
–drop in renal BP leads to salt retention (aldosterone) and worsens the overall hypertension
primary hypertension
–obesity, sedentary behavior, diet, nicotine
secondary hypertension
secondary to other disease
–kidney disease, hyperthyroidism
