TOPIC 2: blood vessels

what arteries are small and can vasoconstrict and vasodilate

muscular (distributing) arteries

what are elastic (conducting) arteries

largest artery, transport high pressure blood, pressure revisour

differences between veins and artery

• artery has small lumen, thick wall and high pressure, carry blood away from heart, oxygenated, deep

• vein is opposite

3 layers of vessel walls

tunica intima -contains endothelium

tunica media - smooth muscle and sheets of elastin

tunica externa - loose collegen fibres - anchor to structures

describe preventable risk factors involved in coronary artery disease

obesitiy, lack of exercise, smoking, high blood sugar, hypertension, dyslidaemia

describe NONpreventable risk factors involved in coronary artery disease

genetics, age, sex , damage to endotheliel layer, plaque

treatment to coronary artery disease

1. artery bypass grafting

2. internal thoracic artery connon to interventricular artery

3. stent into cathada - push in balloon.

desribe basic steps involved in the progression of atherosclerosis

early stages - fatty streak, excess LDL colesterol, foam cells form

fibrous plaque - narrowing of lumen

vulnerable plaque - calcified plaque tissue, platalets stick to damaged area - blood clotting

describe different types of capillaries

• continuous capillaries - most common, least permiable, tight junctions, single layer epithelium

• fenestrated capillary - channels between cells, GL tract, kidneys, endocrine organs

• open or sinusoid capillary - spleen, liver, bone marrow - juntions are open, most permiable

how is blood flow through capillary regulated

1. diffusion through membrane - lipid soluble

2. movement through interceulluar cleft - water soluble

3. movement through fenestrations - water soluble

4. transport via vessles - large substances

describe structure of veins

• largest diametre vessel - low resistance

• collect and store blood - 70% at rest

• lowest pressue

describe three mechanisms in veins that promote venous return to the heart

• muscle pump

• respitory pump - inspiration compress vena cava

• pulse pump - stretch of artery squeezes adjacent veins

what is the heptal portal system

directs nutrient rich, deoxygenated blood from GL tract to liver

during ventricular septal defect what way do you expect blood to move

left to right - left ventricle has higher blood pressure pushing blood back

which tissues have sinusoidal cappiliaries and what purpose do they serve

liver, spleen, bone marrow, endocrine organs, large intercellular cleft allows passage of large molecules

where can pulses be found

temporal, facial, common corotid (most), brachial, radialm femoral, popliteal, posterior tibial

What is the difference between Arteriosclerosis and Atherosclerosis?

Arteriosclerosis:hardening of arteries with age

atherosclerosis: plaque forms in arteries - endothelium damage initates process

describe relationship between hypertension and peripheral resistance

list 4 risk factors related to artherosclerosis

high blood pressure

lack of exercise

age

genetics

smoking

stress

high blood sugar

explain angina

chest pain, narrowed coronary vessle - poor blood flow to heart muscle

describe cappilaries

smallest blood vessle - continuous, fenestrated, sinusid - sites of exchange between tissue and blood - juntions are unjoined leaving intercellular clefts

describe cappillary beds

blood from aorta to ventricle (microcirculation) terminal arteriol branch - post cappillary venule

what are anastomoses

provide altnerate pathways - colateral channels

what is blood flow

equvilant to cardiac output - volumn of fluid flowing

what is blood pressure

force per unit area exterted on vessle wall

what is resistance to flow

amount of friction blood encounters as it passes

what is total blood vessle length

proportional - longer vessle = greater resistance

describe impact of blood vessle diametre

resistance varies inversly - double blood vessle = 1/16 of origninal value

relationship between blood flow, blood pressure and total peripheral resistance

blood flow and blood pressure - directly proportional - increase BP = increase blood flow

blood pressure and resistance = inversly related - increase in BP = increase resistance

highest pressure to lowest pressure

arteries - cappillaries - veins

describe arterial blood pressure and how do you calculate mean arterial pressure

compliance (how much arteries can stretch) -

diastole pressure + pulse pressure/3

what is pulse pressure

difference between sytolic and dyostolic volumn

how do you measure blood pressure

ausculatory method

how is short term blood pressure regulated

alter CO and TPR

role of cardiovascular center in maintaining blood pressure

decrease blood pressure = activate cardioacccelary centre and stimulate vasomotor centre

role of baroreceptors in carotid sinus and aortic arch in blood pressure regulation

reduces HR and contractile force decrease blood pressure increase = baroreceptors stimulated

explain hormonal control in blood pressure

adrenalin, angiotensin II (vasocontrict, rapid rise in BP), atrial natriaretic peptide (reduction of volum, antidiuretic - (increase when very low)

describe long term regulation of BP

Renal mechanism - alter blood volumn

direct: independent of hormones - low BP = conservation of water back into stream

indirect: Angiotensin II - stimulate release of aldosterone, ADH release, Thirst, Vasoconstict

describe hypertension

Chronic elevated BP - 90% primary (no cause) - hereditary, diet, obesity, age, stress, diabetes mellitus, smoking

secondary - obstructed renenl arteries, kidney disease, endocrine disorder

describe hyptension

low BP - 90/60 - no cause or concern

describe circulatory shocks

blood vessles inadequatly filled, and cannot circulate properly

hypovolemic - most common - cause by blood/ fluid loss

vascular shock - poor circulation, BP drop - anaphalaxis, neurogenic, septic shock

cardiogenic shock - pump failure -myocardial damage

what does slow blood flow through cappillaries good for

promotes diffusion of nutrients and gasses and bulk flow of fluids

describe velocity of blood flow

as surface area increases velocity decreases - blood flow is intermittent due to vasomotion

what artery bifurcates to suply head and arms

carotid

what contributes to autoregulation of cappillary blood flow, increasing flow

falling PH, increase CO2, hypoxia

what maintains systemic blood pressure while the heart is filling

recoil of elastic arteries

what do fenestrated cappillaries specifically contain

small openings, allowing passage across endothelial cells as opposed to gaps between cells

what happens to stroke volumn when HR decreases

increase stroke volumn due to