ap cardiovascular system

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ap cardiovascular system

Function of Cardiovascular System

1. Transportation
a. Oxygen, carbon dioxide
b. Delivery of nutrients and hormones
c. Waste removal
2. Temperature regulation
3. Blood clotting
4. Immune function

Location of Heart

1. In mediastinum (btw the lungs)
2. Between body of the sternum and vertebral column (allows you to do cpr)
a. Apex (smallest portion)
b. Base (largest portion)
3. 3.5 in. wide at base
4. 5 in. from base to apex
5. 2.5 in. anterior to posterior
6. Weighs 10 oz

Pericardium

1. Fibrous pericardium (sac around heart)
2. Serous pericardium
a. Visceral & parietal
b. Protection against friction

Myocardial wall

1. Epicardium (visceral pericardium = on top of heart, one cell thick)
2. Myocardium
3. Endocardium (inside, one cell thick)

Cardiac Muscle

1. Elongated, branching cells containing 1-2 centrally located nuclei
2. Intercalated disks: specialized cell-cell contacts. (meshed together) no neurotransmitter junction
a. Cell membranes interdigitate
b. Desmosomes hold cells together
c. Gap junctions (2 channels joined together - continuous, so no missed message) allow action potentials to move from one cell to the next.
Note: twisting, ringing action, when contracts.

Heart Chambers

1. Atria (atrium)
a. receiving chambers
2. Ventricles (left side to the body, a lot more resistance, need more muscle) right ventricle = to lungs, oxygen poor
a. pumping chambers
3. Septums - wall, 2 septums -btw atrium & ventricles)
Note: blood returns to upper chambers, little squeezing to chamber below. ventricles have to go against gravity.

Heart Valves: Atrioventricular (AV) valves

*heart valves prevent back flow, prevents blood from going back to where it came from, want it to go forward
*located btw atrium & ventricles
*valves close based on pressure
1. Chordae tendineae = strings attached to valve. hold valve shut under pressure. don't close the valve
2. Papillary muscles = in wall, attached to valve. hold valve shut under pressure. don't close the valve
3. Tricuspid valve = right side, 3 cuspids
4. Bicuspid, or mitral valve = left side, 2 cuspids

Heart Valves: Semilunar (SL) valves (2)

*heart valves prevent back flow, prevents blood from going back to where it came from, want it to go forward
*heart valves prevent back flow, prevents blood from going back to ventricles, want it to go forward
*no strings attached.
*located btw ventricles and arteries
* open only when heart is pushing blood thru.
* only open when AV valves are closed
1. Pulmonary semilunar valve
2. Aortic semilunar valve

Blood Flow through Heart

1. Superior (above the heart) & Inferior (below the heart) Vena Cava (deoxygenated blood, O2 poor) ------>
2. Right Atrium ----->
3. Through Tricuspid Valve ----->
4. Right Ventricle ----->
5. Pulmonic valve/semilunar valve ----->
6. Pulmonary trunk ----->
7. Right and Left Pulmonary arteries ----->
8. Capillaries of lungs (oxy rich) ----->
9. Pulmonary veins (4 veins, 2 left & 2 right) ------>

Blood Flow through Heart

10. Left atrium (oxygen rich) ----->
11. Through Mitral or Bicuspid valve ----->
12. Left ventricle ----->
13. Aortic valve ----->
14. aorta ----->
15. Arteries ----->
16. Capillaries ----->
17. Veins ------>
18. Superior & Inferior Vena Cava

arteries

1. conduct blood away from heart
2. all arteries except the pulmonary artery & its branches carry oxygenated blood.

veins

1.conduct blood back towards the heart
2. all veins except the pulmonary veins contain deoxygenated blood

Heart Valves: Semilunar (SL) valves - general

1. heart valves prevent back flow, prevents blood from going back to where it came from, want it to go forward
2. located btw ventricles & arteries, shaped like half moons
3. semilunar open only when AV valves are closed
4. no strings attached
5. closes b/c of back flow
6. open only when heart is pushing blood there

Mitral valve prolapse

valve doesn't close completely
murmur - valve doesn't close completely

aorta

major artery of the body.
ascending and then decending

capillaries

1. conduct blood through tissues & permit exchange of materials
2. only place where something happens
3. deliver oxygen & pick up CO2 at the tissue level. lost O2 here

systemic circulation

1. function to deliver oxygen to all body cells and carries away waste & then becomes oxygen poor
2. deoxygenated blood returns to heart by vena cava
3. thru right atrium, then right ventricle, then to lungs by way of pulmonary arteries

pulmonary circulation

1. eliminates CO2 via the lungs and oxygenates the blood
2. oxygenated blood returns to heart via pulmonary veins
3. oxygenated blood pumped to all body tissues via aorta
4. function to oxygenate the blood

Blood Supply of Heart

1. Coronary arteries (gets blood first)
a. Right coronary artery
I. Marginal artery (runs along margins)
II. Posterior interventricular artery
b. Left coronary artery
I. Circumflex artery (goes around to the back of heart)
II. Anterior descending artery (LAD) = feeds left ventricles
2. Cardiac veins - carry blood back to heart. (blue on heart) collected by the coronary sinus.
3. Coronary sinus - posterior surface of the heart
* only time the heart gets blood & O2 is when heart is relaxed

3 ways blood gets into heart

1. superior vena cava
2. inferior vena cava
3. coronary sinus

Anastomosies

making your own blood vessels
your own bypass system

Angioplasty

push blockage back into wall, usually comes back

coronary bypass

add in a vein or artery and go around blockage

Conduction System (5)

-determines how the heart beats, wave of depolarization
1. Sinoatrial node (SA node or pacemaker) - determines rate of beat
2. Atrioventricular node (AV node)
3. Atrioventricular bundle (AV bundle or bundle of His)
4. Purkinje fibers - pieces of conduction system
5. Nerve supply - parasympathetic & sympathetic - can modify

conduction system steps (5)

Step 1. SA node activity & atrial activation begin, depolarize both atria at the same time.
Step 2. stimulus spreads across the atrial surfaces & reaches the AV node
Step 3. there is a delay at the AV node. atrial contraction begins.
Step 4. impulses travels along the interventricular septum w/in the AV bundle & the bundle branches to the Purkinje fibers & via the moderator band, to the papillary muscles of the right ventricle
Step 5. the impulse is distributed by Purkinje fibers & relayed thru out the ventricular myocardium. atrial contraction is completed & ventricular contraction begins.

conduction system steps - various

wave has to go thru before the contraction.
SA node = conduction
wave ----then---->contraction
depolar = nervous
contraction = muscle (after depolarization)

Conduction System Abnormalities - Ectopic

any beat outside the SA node, outside where it is suppose to be

Conduction System Abnormalities - Arrhythmia

abnormal rhythm, time span btw each beat is irregular

Conduction System Abnormalities - Bradycardia

slow.
heart rate is less than 60 (relate it to activity vs. inactivity

Conduction System Abnormalities - Tachycardia

fast
heart rate over 100

Conduction System Abnormalities - Fibrillation

you don't have meaningful rate, quivering, you won't pump out any blood

Conduction System Abnormalities - Asystole

flatline, no contraction

systole

heart contraction
ventricles contracting

distole

relaxation
ventricles relaxed

blood pressure

systole divided by distole

defribillation

shuts down system

electrocardiogram

can measure electrical and mechanical
record of the electrical events that precede contractions

P wave

1. SA node initiation, electrical impulse thru both atria
2. Atrial depolarization

QRS complex

Ventricular depolarization
Atrial repolarization

T wave

Ventricular repolarization
* repolarization is electical

artifical pacemaker

SA node doesn't work
measures length of tiem w/in beats. there is a threshold & will beat for you if you don't on your own

blood vessels - 6 types

1. Artery
2. Arteriole
3. Capillary
4. Venule
5. Vein
6. Sinus

Artery function

1. carry blood away from the heart to arterioles
2. muscles in wall, responsible for blood pressure

Capillaries function

1. exchange vessels, delivery & pickup only thru capillary bed
2. need to go thru slowly for delivery & pickup

Arterioles function

1. resistance vessels, resistant to blood flow
2. smaller

Veins function

1. carry blood towards the heart, capacitance vessels
2. hold a lot more blood than artery. not as much muscle, they can stretch

sinus function

1. a wide blood vessel that does not have the same structure of a vein
2. back towards the heart

Structure of Arteries & Veins (3)

1. Tunica adventitia or externa = outer layer
2. Tunica media = muscle
3. Tunica intima or interna = inner layer, simple squamous, one cell thick. prevents blood from clotting

* could be a valve in vein - prevents backflow of blood, only when going against gravity. area below the heart
*lumen - open space inside tube
*vein = not as muscle as an artery

Comparison of Arteries & Veins

Direction of flow
Arteries = Carry blood away from the heart
Veins = carry blood towards the heart
Pressure
Arteries = Higher - Normally <120/80 mm Hg
Veins = Lower - Normally not measured (CVP)
Walls
Arteries = Thicker: Tunica media thicker than tunica externa (especially muscle)
Vein = Thinner: Tunica externa thicker than tunica media
Lumen
Arteries = Smaller. Veins = Larger
Valves
Arteries = No valves Veins = Valves

Capillary Structure (3)

function is exchange
1. Simple squamous epithelium
2. Endothelium
3. Pores = things get out, fluid. albumin will leak out

Precapillary Sphincter

muscle outside of tube, when they constrict they cut off the tube (capillary)

capillary tissue

taking blood away from tissue (ex. skin & lungs

Systemic Arteries (5)

1. Coronary arteries - first off ascending aorta
2. Brachiocephalic trunk - ("arm-head") aortic arch, clot=stroke
3. Left common carotid artery - aortic arch, blood to head
4. Left subclavian artery - aortic arch, blood to arm
5. Left and right common iliac arteries

Systemic Veins (2)

1. Superior vena cava - merger of brachiocephalic veins
2. Inferior vena cava - merger of 2 common iliac veins, initiates pelvic cavity

Hepatic Portal System

1. digestive - liver gets first & then everywhere else
2. inferior & superior mesenteric veins & splenic veins - all three come together to hepatic portal system

Fetal Circulation (6)

1. Umbilical arteries - O2 poor, extensions of internal iliac arteries and lead to placenta
2. Placenta - exchange of O2 & nutrients btw maternal and fetal blood. diffusion, capillaries
3. Umbilical vein - O2 rich, from placenta, towards heart
4. Ductus venosus - bypasses liver
5. Foramen ovale - bypass lungs. opening in septum btw right and left atrium. turns into fossa ovalis
6. Ductus arteriosus - bypass lungs. connects pulmonary artery w/descending aorta. turns into ligamentum arteriosis

Fetal Circulation: Placenta

Responsible for delivery of nutrients, removal of waste products and delivery of oxygenated blood to the fetus.

Fetal Circulation: Circulation bypasses the lung

1. Fetus is not breathing or oxygenating blood.
2. Foramen ovale & ductus arteriosus

Fetal Circulation: Circulation bypasses liver

1. Fetus is not detoxifying blood.
2. Ductus venosus

Fetal Circulation - other

1. Blood returning to right atrium (IVC w/O2 rich blood) --> foramen ovale to left atrium
2. Blood pumped by right ventricle into pulmonary artery (SVC) --> ductus arteriosus to aorta
3. Umbilical vein instead of flowing through liver --> ductus venosus into IVC.
4. Changes in circulation at birth

Atherosclerosis

hardening of arteries. inside wall of artery. plaque btw muscle & endothelium
1. Ischemia - diminished blood flow ex. angina
2. Infarction - tissue dies due to cut off of blood supply
3. Thrombus
4. Embolus

Effects of Atherosclerosis: Heart

1. coronary arteries partial occulsion = angina, heart disease
2. total occlusion = myocardial infarction (heart attack)

Effects of Atherosclerosis: Brain

1. carotid/cerebral arteries, partial occlusion = transient ischemic attack
2. carotid/cerebral arteries, total occlusion = stroke

Effects of Atherosclerosis: Peripheral arteris

1. aorta = aneurysm, occlusion, rupture & hemorrhage
2. legs = peripheral vascular disease - gangrene and amputate

Cardiac Cycle: 5 phases

a complete heartbeat
1. Atrial systole = contraction
2. Isovolumetric ventricular contraction
3. Ejection
4. Isovolumetric ventricular relaxation
5. Passive ventricular filling

Atrial Systole: 1st phase

1. AV valves open between atria and ventricles
2. Semilunar valves closed (closed most of the time) between ventricles & arteries
3. SA node fires, atria depolarize
4. P wave appears on ECG
5. Atria contract
6. Force additional blood into ventricles

Isovolumetric Ventricular Contraction: 2nd phase

1. Atria repolarize and relax
2. End diastolic volume (EDV) = how much blood is in ventricles before you contract
3. Ventricles depolarize
4. QRS complex appears in ECG (electrical)
5. Ventricular systole
6. Ventricular pressure increases closing AV valves - (Lub = first heart sound - closing AV valve)

Isovolumetric Ventricular Contraction: 2nd phase
part 2

1. isovolumetric = no change in volume
2. when pressure in ventricle is greater than atria --then--> AV closes
3. pressure starts to rise & when ventricle pressure exceeds arteries --then--> semilunar valves open. this is called ejection

Ejection: 3rd phase

1. Increasing ventricular pressure
2. When pressure in ventricles > pressure in arteries (pulmonary & aorta) semilunar valves open
3. Initially rapid outflow of blood
4. As ventricular pressure drops outflow of blood falls
5. Stroke volume = amount of blood ejected
6. Ejection fraction = amount of EDV actually ejected
7. End-systolic volume = amount of blood left in heart

Isovolumetric Ventricular Relaxation: 4th phase

1. Ventricles repolarize and relax
2. T wave appears in ECG
3. Pressure within ventricles fall
4. Blood in arteries flows back towards heart
5. Semilunar valves close (Dub = second heart sound)
6. AV valves remain closed
7. Pressure continues to fall
all four valves are closed

Passive Ventricular Filling: 5th phase

1. While the ventricles were in systole, the atria were filling with blood.
2. When pressure in ventricles drops below pressure in atria AV valves open
3. Blood sitting in atria passively flows into ventricles

Cardiac Cycle

1. Systole: ventricles contracting
2. Diastole: ventricles relaxed

Carotid artery atherosclerosis

atherosclerotic plaque - collects at split, mostly on interior carotid - then no blood to brain

Aneurysm

you will have uneven pressure. weakening in wall
Fusiform - bubble on both sides
Saccular - thrombus on one side
Dissecting (worst) - creates a false passage, blood goes down passage

Principle of Circulation

1. Hemodynamics - physical principles of blood flow based on pressure and resistance
2. Blood flows due to pressure gradient (blood pressure)

Principle of Circulation: Arterial Blood Pressure

1. Systolic pressure - in artery when blood is contracting
2. Diastolic pressure - in artery when blood is relaxing
3. Major Influences
a. Cardiac output - amount of blood pumped out of a ventricle each minute
b. Peripheral resistance - resistance to blood flow due to diameter of blood vessels and viscosity of blood

Cardiac Output

1. Cardiac output (CO) (use in relation to body)
CO = SV times HR
a. Stroke volume (SV) = amount of blood pumped by a ventricle per beat
b. Heart rate (HR) = number of heart beats per minute
c. Influenced by several factors

Cardiac Output: Stroke volume (determined by 3 factors)

Stroke volume
Determined by three factors:
1. Preload - whats in heart before it contracts
2. Contractility - strength of contraction
3. Afterload - what it pushes against

Cardiac Output: Heart rate (determined by 2 things)

Heart rate
Determined by
1. Nervous Input
2. Hormones

Preload

= volume. linked to contractility
depends on how much blood is coming back to heart
1. Amount of blood in ventricles prior to contraction
2. Determined by end-diastolic volume and venous return.
3. More end-diastolic volume - more stretch on muscle fibers
4. Increase preload causes-> Increase force of contraction (and more blood will pump out)
5. Starling's Law of the Heart

Contractility

= force
1. Force of myocardial contraction
2. Determined by preload, condition of heart muscle (ex. scar tissue) & presence of inotropic agents (any drug that effects contractility)
3. Positive inotropic agents - factors that  contractility3.
Examples: catecholamines, digitalis
4. Negative inotropic agents factors that  contractility
Examples: hyperkalemia, hypocalcemia (both ions in body)

hyperkalemia

increase in potassium.
too high or too low effects the heart

hypocalcemia

decrease in calcium
if low then heart doesn't have force to contract & might have blood left behind

Starling's Law of the Heart

Relationship between stretch on myocardial muscle fibers (EDV) and amount of blood pumped (SV)

Afterload

= resistance
1. Amount of resistance the ventricles must contract against (how big is the blood vessel)
2. Determined by diameter of arteries and arterioles as well as blood viscosity.
3. More resistance - more afterload
4. Increase afterload causes increase work of the heart
diameter most important - smaller the diameter the harder the heart has to work

Baroreflex or Vasomotor Pressoreflex

autonomic reflex arc. pressure reflex in muscles.
1. Changes in BP detected by stretch receptors (baroreceptors), in large arteries above heart
a. Aortic sinuses (behind aortic valve cusps)
b. Carotid sinus (base of each internal carotid artery) dilation of _____w/a receptor in it.
2. Vasomotor and cardioinhibitory centers in medulla
3. Inc. BP causes rate of signals to rise, inhibits vasomotor center, decrease sympathetic tone, stimulates cardioinhibitory center, increase parasympathetic output
4. Decr. BP causes rate of signals to drop, excites vasomotor center, incr sympathetic tone, inhibits cardioinhibitory center, decr. parasympathetic output

Baroreflex or Vasomotor Pressoreflex: main function & correction

1. prevents damage from sudden increase in BP. ex. you get excited and pass out. effector is heart & blood vessels
2. to correct decrease in BP
- drop resistance by dilating vessels (controlled by sympathetic). change cardiac output = turn down sympathetic and turn up parasympathetic.
3. to correct increase in BP = opposite of above

Chemoreflex

1. Chemoreceptors in aortic bodies and carotid bodies
a. located in aortic arch, subclavian arteries, external carotid arteries (measure chemicals in body)
2. Responds to changes in blood chemistry
a. pH, O2, CO2 (BP can change due to breathing problems)
b. Stimulated by hypoxemia, hypercapnia and acidosis, resulting in Vasoconstriction

won't test on BP but will on respiratory

Venous return

-effects EDV
A. Amount of blood returned to heart by veins
B. Gravity drains blood from head and neck
*1. Skeletal muscle pump in the limbs (will squeeze the vein - works from legs to pelvis)
*2. Thoracic pump - when you inhale. breathing brings blood up to the heart just to get into inferior vena cava
C. Cardiac suction of expanding atrial space

Control of Venous Return

1. Control fluid in body - control amount of blood returning to heart
2. Control of fluid by:
a. ADH mechanism - draw in water, Incr. blood volume, Incr. EDV, incr. Cardiac output. Decr. urine volume
b. Renin-angiotensin mechanism - based on BP. decrease in BP, then increase renin, increase blood volume, incr. venous, incr CO
c. ANH mechanism - hormone

Control of Venous Return: ADH mechanism

control fluid by:
draw in water, retain water
increase blood volume, EDV, cardiac output
decrease urine volume

Control of Venous Return: Renin-angiotensin mechanism

based on BP
decrease in BP then increase Renin
increase blood volume, venous, cardiac output

Control of Venous Return: ANH mechanism

1. Atrial naturietic hormone
2. release by atria when overstretched.
3. lose sodium & water. causes excretion of salt & water follows
4. Increase urine volume, cardiac output
5. decrease blood volume, EDV & venous
6. antagonistic to ADH & Renin

Starling's Law of the Capillaries (see separate print out)

-movement of fluid in & out of capillaries
1. Opposing forces
a. Blood pressure (aka hydrostatic pressure) drives fluid out of capillary
i. high on arterial end of capillary, low on venous end
b. Osmotic pressure (or colloid osmotic pressure) draws fluid into capillary
i. results from plasma proteins
2. Hydrostatic pressure
a. Physical force exerted against a surface by a liquid
3. Imbalance in forces cause edema

Left Ventricular Failure

1. rt. ventricular output exceeds left ventricular output
2. pressure backs up
3. fluid accumulates in pulmonary tissue

if fluid in left ventricle backs up it back up everything else and eventually backs up into lungs & air sacs = fluid on lungs

Right ventricular failure

1. keft ventricular output exceeds right ventricular output
2. pressure backs up
3. fluid accumulates in systemic tissue

if fluid in right ventricle backs up it back up everything else and eventually edema in gravity areas - ankles, abdomen, jugular veins and eventually problems in lungs

Blood pressure

Need to collapse the artery to perform
1.Systolic blood pressure - hear 1st sound
2. Diastolic blood pressure - sound goes away. pressure that is there all the time.
3. Pulse pressure - difference btw systolic & diastolic. causes blood to flow

Normal less than 120/80 mm Hg
Hypertension (140/90)
Hypotension (90/60) really depends on how person reacts. i.e. brain function

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