Chapter 21 Blood Vessels Part 1 Flashcards
what is the ductwork that carries blood to the body tissues and back to the heart
blood vessels
blood vessels regulate blood pressure to maintains what
tissues metabolic needs
bloood vessels determines degree of what
blood flow to the bodys most active tissue
what are the 2 sets of circulatory blood vessels
pulmonary and systemic
right side of the heart
pulmonary
left side of the heart
systemic
what are the 5 circulatory system func.
- carries blood
- exchanges nutrients, waste products and gases
- transports substances
- regulates BP
- blood flow to tissues to maintain homeostasis
what are the 3 bv types
arteries
capillaries
veins
each bv has what
3 layers or tunics that comprise it
how many layers does tunica intima have
4
what are the three layers
tunica intima
tunica media
tunica externa
endothelium, basement membrane, lamina propria and internal elastic membrane is
tunica intima
what layer is smooth mscule and elastic with collagen fibers
tunica media
vasoconstriction and vasodilation is in what layer of bv
tunica media
smooth muscle contraction and reduced Bv diameter
vasoconstriction
smooth muscle relaxation and increased BV diameter
vasodilation
what seperates middle and external layer
external elastic membrane of tunica media
what layer is made of ct
tunica externa
what layer is dense on inner portion and loose is outer
tunica externa
= Carry blood away from the heart (Branch)
arteries
Thickest vessels with smooth muscle & elastic fibers
artery
As vessels become smaller, Artery walls undergo Gradual transition from Large amount of
Elastic tissue & Smaller Smooth muscle to having MORE Smooth muscle
artery
= Most common type of BV, Thinnest
capillaries
Inner lining of Simple squamous epithelium = Endothelium
capillaries
= Carry blood toward the heart (Merge)
veins
Contain Valves that help to prevent backflow, Found more in lower extremities
veins
– Largest diameter = Conducting; BP is high, Stretch & Recoil, Tunica intima is thick
elastic arteries
– Medium sized & Small arteries = Distributing; Thick Tunica media
muscular arteries
– Smallest arteries, Vasoconstriction & Vasodilation
arterioles
NO Gaps between Endothelial cells, Less permeable to large molecules
In skin, muscle, lungs, CNS
continous capillaries
NO cytoplasm, Thinner PM. Seen in highly permeable area
Intestinal Villi, Kidney glomeruli, Choroid plexus of CNS
fenestrated capillaries
– Larger diameter; In Liver or Endocrine Glands
sinusoidal capillaries
– Smallest veins, when smooth muscle fibers form continuous layer = Small veins
venules
– Transport of blood from small veins toward the heart
medium and large veins
Connection of Capillary network to another
Seen in Hepatic, Hypothalamic-Hypophyseal Portal vein & Renal Nephron Portal System
portal veins
varicose veins affect what %
more than 15
what is due to incompetent valves
tortuous and dilated veins
when do varicose veins occur
due to xs stretch of veins & valves no
longer overlap to prevent blood backflow. Venous
pressure is greater Edema
what do you feel in ur legs in varicose veins
heaviness in legs
what does varicose veins lead too
phlebitis
phlebitis sffects what
superficial
risk factors for varicose veins
Genetics, Prolonged standing,
Obese, Pregnancy, Straining in Labor & with BM
what is blood circulation determined by
Flow, Resistance & Pressure
Volume of Blood flowing through a vessel, organ or entire circulation in given period
Equivalent to Cardiac Output (CO) & at rest is basically constant. CO = SV (ml/beat) x HR
Entire Blood supply pumps through each side of heart 1x / min
blood flow
= Force per unit area exerted on a vessel wall by contained blood, Measurement in mmHg.
blood pressure
Opposition to Flow & measure of amount of friction blood encounters as passes through vessels.
Total peripheral Resistance (TPR) (where encounter friction in peripheral system)
resistance
3 sources of blood circulation
blood viscosity
vessel length
vessel diameter
blood flow is directly proportional to difference in BP between 2 points in circulation= BP gradient
difference in BP increases, so does
blood flow
blood flow is indirectly proportional to TPR. As TPR increases what decreases
blood flow
Neural Controls (Baroreceptors & Chemoreceptors)
Respond to changes in Arterial pressure & stretch
Receptors respond to changes in blood levels of CO2, H+, O2
Controlled by Higher brain centers (Hypothalamus)
short term control
Hormonal Controls – Adrenal medulla hormones (Epi & NE). Angiotensin II (Rise in BP),
ANF (Drops BV & BP), ADH (Vasopressin) = All increase BP except ANF
short term control
Renal mechanisms alter blood volume via kidneys.
Increase in BV (xs salt intake) causes increase in BP via water retention
Decrease in BV (dehydration) causes decrease in BP with vigorous exercise & Blood loss
long term control
long term control directly or indirectly : NO hormones; BV or BP rises Filtration faster (Kidney tubules)
If High = Drop, If Low retain water & Rises
directly
long term control directly or indirectly : Renin-Angiotensin-Aldosterone mechanism
If BP drops, Kidney cells release Renin,
Renin splits Angiotensinogen (made in liver) converts to Angiotensin I.
Angiotensin I converts to Angiotensin II via Angiotensin Converting
Enzyme (ACE) (in capillary epithelium – ie lungs
indirectly
4 ways angiotensin II stabilizes BP
Aldosterone secretion, ADH release,
Activates Hypothalamic Thirst center (Drink more),
Also increases TPR as it is potent as a vasoconstrictor
chronic elevation in BP
hypertension
what do you need to do when you have hypertension
need to change lifestyle as silent killer
risk of hypertension
risk of HF, RF, vascular disease, CVA
higher resistance of hypertension=
work harder and myocardium enlarges, strains, weakens walls become flabby also atherosclerosis
primary not ID cause:
genes, diet, obese, over 40, DM, stress, smoking, NOT cure but control. meds ACE inhibotors, diuretics, beta blocker, calcium channel blockers
secondary Id cause=
renal artery stenosis, kidney disease, hyperthyroid, cushings
Low BP, <90/60. Usually long life. (Acute Circulatory Shock)
hypotension
what is orthostatic hypotension:
temporary drop in BP causing dizziness, with sudden rise
old is at risk as SNS does not respond as quickly to
postural changes
blood temporarily pools in lower limbs, BP drops and less blood to brain. what do you need to do?
change position slowly
chronic hypotension is
serious underlying condition- addison’s disease, hypothyroid, severe malnutrition
Circulatory = BV inadequately filled & blood not circulate properly, Body needs not met. Cells destroyed & Organ damage
shock
most common form of shock, Low volume due to major blood/fluid loss (Severe Vomiting/Diarrhea, Acute Hemorrhage,
Burns). Rapid decrease = weak thready pulse, due to intense vasoconstriction. NEED to replace volume ASAP!
hypovolemic
= Blood volume normal, but poor circulation due to xs vasodilation. Drop in TPR then BP drops.
vascular
3 types of shock
anaphylatic shock
neurogenic failure
septic shock
systemic allergic reaction with massive histamine release triggering vasodilation throughout system
anaphylatic shock
failure of ANS regulation
neurogenic
due to severe systemic bacterial infection causing widespread vasodilation
septic shock
Pump failure when hear cannot sustain circulation. Due to MI Myocardial damage.
cardiogenic
