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โ๐๐๐ก๐ฅ๐๐ฃ ๐๐ ๐น๐๐ ๐ ๐ ๐๐๐ค๐ค๐๐๐ค ((pulmonary a is a branch ofโฆ
โ๐๐๐ก๐ฅ๐๐ฃ ๐๐ ๐น๐๐ ๐ ๐ ๐๐๐ค๐ค๐๐๐ค
โโ.โ
๐ ๐ ก๐ ฃ๐ ๐ ก๐ ๐ ๐ ข,
๐ ๐ ก๐ ฃ๐ ๐ ก๐ ๐ ๐ ๐ ๐ ข,
๐ ๐ ๐ ๐ ๐ ๐ ๐ ๐ ก๐ ๐ ๐ ข,
๐ ฅ๐ ๐ ๐ ค๐ ๐ ๐ ข,
๐ ฅ๐ ๐ ๐ ๐ ข
Capillaries
Smallest vessel; endothelial cells; only tunica intima; permit exchange of gasses, nutrients and wastes; connect arterioles to venules; arrangement varies by tissue being supplied;
diffusion (most common) - lipid soluble substances pass through endothelial cell membrane, water soluble passes through gaps between endothelial cells
vesicular transport ( endo/exocytosis)
bulk flow (filtration and absorption)
filtration - hydrostatic (blood) pressure; colloid osmotic pressure (osmosis) draws fluid back into capillary
normal pressure 20-30 mmHg
Venules
tunica I&E;
Arterioles
smaller arteries; may help form anastosomes by uniting with branches of other arteries supplying the same region; deliver blood to capillaries; regulate BP;
Veins
Larger lumen than vein; carry blood toward heart; low pressure; contain valves; high in co2; large - serve as blood reservoir especially in skin
Arteries
Smaller lumen than vein; largest is the aorta; blood is high n oxygen; higher pressure than veins; tri-layered like
like trident GUM
; ventricular systole is highest bp
S T R U C T U R E
Tunica Media
- middle layer; contains smooth muscle tissue in a framework of collagen and elastic fibers; when smooth muscles contract, vessel diameter decreases - relaxation=increased diameter
Tunica externa (aventitia)
- forms sheath of connective tissue around the vessel; collagen fibers my intertwine with those of adjacent tissues stabilizing and anchoring blood vessel
Tunica intimia (interna)
- innermost layer; includes endothelial lining and underlying layer of connective tissue dominated by elastic fibers
โโ.โ ๐ ๐ ๐ ๐ ๐
๐ ๐ ก๐ ๐ ข๐ ข๐ ค๐ ก๐
factors affecting blood flow
vascular resistance
viscosity
- resistance to flow resulting from interactions among molecules and suspended materials in a liquid
pressure
force exerted against a liquid generates fluid(hydrostatic) pressure that is conducted in all directions; pressure difference=flow from high BP to low BP,
pressure gradient
;
circulatory pressure
- pressure difference, avg 100 mmHg
three components
arterial pressure - used for blood pressure
capillary pressure
venous pressure
turbulence - cause 3rd and 4th heart sounds
resistance
any force that opposes movement; circulatory BP must be great enough to overcome
total peripheral resistance (resistance of entire CV system
; greatest pressure difference is ~65 mmHg
peripheral resistance
- resistance of arterial system
viscosity :arrow_up: = bp :arrow_up:
turbulence - blood hitting walls of blood vessels
vascular resistance is...
resistance of blood vessels to blood flow
mostly occurs in arterioles(extremely muscular); local, neural, and hormonal stimuli that stimulate or inhibit contractions of this smooth muscle tissue adjust diameter
small diameter change produces large change in resistance
most important factor is friction between the blood and the vessel wall (friction depends on length and diameter of the vessel); controlled by changing diameter of blood vessels
interplay between pressure and resistance
CV pressures within the systemic circuit
BP (arterial pressure)
Capillary pressure and capillary exchange
venous pressure
tachycardia - rapid hr
bradycardia - slow hr
pulse pressure- difference between systolic and diastolic bp
venule side blood moves into vessel - bop :arrow_up: chp
no net fluid movement - chp = bop
arterial side blood moves into tissues - capillary hydrostatic pressure :arrow_up: blood osmotic pressure
โโ.โ
๐ ๐ ๐ ก๐ ๐ ๐ ๐ ฅ๐ ๐ ข๐ ๐ ค๐ ๐ ๐ ก
๐ ก๐ ๐ ๐ ค๐ ๐ ๐ ฃ๐ ๐ ๐
autoregulation
precapillary sphincters - alter peripheral resistance
vasodilators
- promote dilation of precapillary sphincters
vasoconstrictors
-stimulate the constriction of precapillary sphincters
neural regulation
barorecetors
- pressoreceptors; detect changes in BP in aorta and in carotid arteries ; ones that function in regulation of BP are located in carotid sinus
chemoreceptors
- detect changes in key blood chemical concentrations (H+, CO2, O2)
Hormones/Endocrine Regulation
increase BP (cause vasoconstriction)
antidiuretic hormone (ADH) - posterios pituitary gland, increases reabsorption of water by the kidneys (DCT) direct increase in blood vol
angiotension - renin released from kidneys; four diff targets, secretion of aldosterone, adh, and stimulate cardiac output; increases peripheral resistance
erythropoietin - RBC production
Atrial Natriuretic Peptide - increases Na+ and h2o reabsorption in the kidneys
epinephrine & norepinephrine - increases CO
increase blood flow to kidneys
decrease bp
atrial natriuretic peptide (ANP)
histamine - vasodilation; plays h=key role in inflammation
13.4 the cardiovascular system adapts to physiological stress
at rest 5.8 liters/min
as exercise begins
extensive vasodilation
venous return increases
cardiac output increases
hemorrhage
long term (fluid retention)- ADH, aldosterone, increase thirst; EPO
shock - acute circulatory crisis (hypotension;pale,cool moist sin; confusion & disorientation - no blood to brain; rapid/weak pulse; no urine; brop in blood pH
short term - blood donation, venous reserve(venoconstriction), sympathetic stimulatin (major loss of blood)
13.5 the pulmonary and systemic circuits of the cardiovascular system exhibit 3 general functional patterns
distribution of arteries & veins on both sides = identical
vessels may undergo name change
CV
pulmonary circuit & systemic cicuit
tissues + organs are services by serveral arteries + veins
13.6 In the pulmonary circuit, deoxygenated blood enters the lungs in arteries and oxygenated blood leaves lungs in veins
PULMONARY CIRCUIT
r+l pulmonary arteries (deO2 blood)
cappilaries in lungs
pulmonary trunk
r+l pulmonary veins
13.7 the systemic circuit carries oxygenated blood from the left ventricle to tissues other than the lungsa exchange surfaces an returns deO2 blood to the right atrium
arterial system
aorta
ascending a (r+l coronary artery)
aortic arch (brachiocephalic - basilar (brain) circle of willis, right subclavian
thoracic a
abdominal a (branches into common iliac arteries; celiac trunk, superior mesentric, renal arteries, inferior mesentric)
common iliac arteries - external iliac
femoral
systemic circuit - vessels that carry blood from the heart to body cells and back to heart
arterial :red_flag:
venous
2 brachiocephalic veins
hepatic vein (portal)
gastric vein
mesenteric v
sphenic v
jugular veins (head)
longest vein in body - great sphenous vein
external jugular veil returns bllood from face to heart
small veins of the brain empty into to dural sinuses
celiac artery provides blood to liver and spleen
superior mesentric a supplies blood to parts of intestinal tract
internal carotid supplies blood to brain
circle of willis (anastomosis) interconnect carotids and basilar artery
13.8 - modifications of fetal and maternal cardiovascular systems promote exchange of materials, and independence is achieved at birth
embryonic lungs are collapsed, digestive tract has no food
fetal circulation in the heart and great vessels
foramen ovale - one way valve thru interatrial septum
ductus arteriosus (pulmonary and aortic trunks)
placental blood supply
umbilical arteries - rise from internal iliac a
placenta - exchange of nutrients
umbilical vein - liver, ductus venosus (inferior vena cava)
circulatory changes at birth
foramen ovale closes, ductus arteriosus becomes ligamentum arteriosum
13.9 - aging affects the blood, heart and blood vessels
heart
reduce CO, changes in nodal/ conduction cells, reduced elasticity of fibrous skeleton, atherosclerosis, scar tissue
blood vessels
inelastice walls (aneurism, stroke, MI, masssive blood loss); calcium deposits; thrombi can form at the atherosclerotic plaues
blood
decreased hematocrit (RBC); constriction/ blockage (thrombus of embolism); pooling of blood (ales not working)
pulmonary a is a branch of pulmonary trunk
in response to hemorrhage there is mobilization of the venous reserve
has decreased posterior pituitary - decreased blood vol
the blood hydrostatice pressure and the blood osmotic pressure are equal in magnitude but in opp direction would completely stop all NET filtration
plasma proteins that remain in the blood capillaries maintain osmotic pressure of b
