Chapter 13- human physiology 2

Cardiovascular system

the cardiovascular system is made up of what 3 things?

heart, blood vessels, blood

what is the 3 main functions of the cardiovascular system?

transport oxygen and nutrients to cells, transport wastes to liver and kidneys, transport hormones/immune cells/clotting proteins to target cells

heart to veins order (6)

heart, arteries, arterioles, capillaries, venules, veins

Arteries

large, branching vessels bring blood away from the heart

arterioles

small branching vessels with high resistance

capillaries

site of exchange between blood and tissue

venules

small converging vessels carrying deoxygenated blood

veins

large converging vessels that conduct blood towards the heart

the cardiovascular system is what type of system (1)?

closed

what are erythrocytes

red blood cells

what do erythrocytes do?

transport oxygen and carbon dioxide around the body

what are leukocytes

white blood cells

what do leukocytes do?

defend body against pathogens/illness

what are platelets

proteins of cell fragments

what do platelets do?

helps in blood clotting

what is plasma

fluid and solutes

pulmonary circuit come from

the right side of the heart

pulmonary circuit involves

blood vessels from the heart and lungs

the systemic circuit comes from

the left side of the heart

the systemic circuit involves

blood vessels from the heart to the tissues of the body and to the heart

what occurs at the pulmonary capillaries

blood enters the lungs and gets oxygenated then leaves the lungs to the heart

what occurs at the systemic circuit

blood enters the tissues and gets deoxygenated

independent regulation allows for what

regulation of how much blood goes to specific organs when blood is needed more in certain areas of the body

blood in the chambers of the heart does NOT do what

supply nutrients to the cardiac cells

coronary (heart) circulation is fed by what

the hearts own capillaries from the coronary arteries that come from the aorta

what separates the heart from the abdominal cavity

diaphragm

heart height and weight

size of fist, 250-350 grams

what is the pericardium and what does it do

membranous sac surrounding the heart which lubricates the heart to decrease friction when pumping

what is pericarditis

inflammation of the pericardium around the heart

what are the 3 layers of the heart from inside to outside and what are they made of?

endothelium (endothelial cells) , myocardium (cardiac muscle) , epicardium (external membrane)

right atrioventricular valve is also called

tricuspid valve

left atrioventricular valve is also called the

bicuspid valve or mitral valve

what pulls the valves open and makes sure they do not collapse (2)

papillary muscles and chordae tendinae

what are the two semilunar valves

aortic valves and pulmonary valve

autorhythmicity

the ability to generate their own rhythm

autorhythmic cells do what

lay out pathway for spreading electrical activity through the heart

pacemaker cells do what (2)

spontaneously depolarize membrane to generate action potentials, provide rhythm to the heart beat

conduction fibers do what

quickly conduct action potentials from pacemaker cells into the myocardium

conduction velocity of conduction fibers

4 meters per second

conduction velocity of ordinary muscle fibers

0\.4 meter per second

2 pacemaker cells of heart

sinoatrial node and atrioventricular node

3 conduction fiber of the myocardium

internodal pathways, bundle of his, purkinje fibers

which autorhythmic cells have the highest firing rate? what was it?

sinoatrial node, 70-80 action potentials per minute

intercalated disks

junctions between adjacent myocardial cells

desmosomes do what

resist mechanical stress of myocardial contraction

electrical coupling in the heart travels using what

gap junctions

first step of conduction of the heart

action potential initiated in sinoatrial node, signal spread through atrial muscle using interatrial pathways

second step of conduction of the heart

signal travels to atrioventricular node from the internodal pathways, atrioventricular node delay

third step of conduction of the heart

atrioventricular node fires carrying electrical signal to bundle of his

fourth step of conduction of heart

electrical signal splits into left and right bundle branches

fifth step in the conduction of the heart

electrical signal travels from the bundle branches to the purkinje fibers

atrioventricular delay is how long

0\.1 second

steps of excitation in heart

sa node, internodal pathways, right atrium, left atrium, av node, bundle of his, bundle branches, purkinje fibers, ventricles

ventricles contract what way

from the apex (bottom) up

autorhythmic cells have what type of potentials

pacemaker potentials

Na+ and K+ channels in heart cause

net depolarization

Ca2+ channels in heart cause

further depolarization

Phase 0 of electrical activity in cardiac cells

increased permeability to Na+

Phase 1 of electrical activity in cardiac cells

decreased permeability to Na+

Phase 2 of electrical activity in cardiac cells

increased permeability to Ca+, decreased permeability to K+

Phase 3 of electrical activity in cardiac cells

increased permeability to K+, decreases permeability to Ca+

Phase 4 of electrical activity in cardiac cells

resting membrane potential

what is the long duration cardiac contracile action potential

250-300msec

skeletal muscle contactile cell action potential is how long

1-2 msec

step one of excitation contraction coupling

depolarization of cardiac contractile cell to threshold due to gap junctions

step two of excitation contraction coupling

opening of calcium channels in plasma membrane

step three of excitation contraction coupling

action potential travels down T Tubules

step four of excitation contraction coupling

calcium is released from sarcoplasmic reticulum

step five of excitation contraction coupling

calcium binds to troponin, causing tropomyosin to shift

step six of excitation contraction coupling

binding sites for myosin on actin are exposed

step seven of excitation contraction coupling

crossbridge cycle occurs

to relax muscle what occurs

calcium is removed from the cytosol by Ca+ATPase in sarcoplasmic reticulum and plasma membrane and Na+-Ca+ exchanger in plasma membrane

to relax muscle what structures have to return to their resting state

calcium unbinds from troponin allowing tropomyosin to cover myosin binding sites

Electrocardiogram (ECG) does what

record electrical activity of the heart to identify abnormalities

distance and amplitude of electrical potential spread depends on what two factors

size of action potentials and synchronicity of potentials from other cells

P wave

atrial depolarization

QRS complex

ventricular depolarization and atrial repolarization

T wave

ventricular repolarization

PQ segment

Atrioventricular node delay

QT segment

ventricular systole

QT interval

ventricular diastole

sinus rhythm

pace generated by SA node

tachycardia

fast rhythm

bradycardia

slow rhythm

first degree heart block symptoms (3)

slowed conduction of AV node, increase PQ segment duration, larger delay between atrial and ventricular contraction

second degree heart block symptoms (3)

slowed or stopped conduction of AV node, lose 1 to 1 relationship between P wave and QRS complex, lose 1 to 1 relationship between atrial and ventricular contraction

third degree heart block symptoms (3)

loss of conduction through AV node, P wave becomes independent of QRS, atrial and ventricular contractions are independent

extra contraction in heart results in, by what

results in extra systole, caused by premature atrial contraction with extra ventricular contraction

ventricular fibrillation

loss of coordination of electrical activity of the heart, results in death

systole

ventricle contraction

diastole

ventricle relaxation

phase 1 of cardiac cycle (ventricular filling) (5)

middle of ventriular diastole, venous return, AV valves open, blood moves from the atria to ventricles, pulmonary and aortic valves are closed

phase 2 of cardiac cycle (isovolumetric ventricular contraction) (4)

start of systole, ventricles contract, AV values close, no blood entering or exiting

phase 3 of cardiac cycle (ventricular ejection) (5)

remainder of systole, pressure in ventricles is higher than arteries, semilunar valves open, ventricle pressure decreases, semilunar valves close

phase 4 of cardiac cycle (isovolumetric ventricular relaxation)

onset of diastole, ventricle relaxes decreasing pressure, AV and semilunar valves close, no blood entering or exiting

dicrotic notch

in systole when backflow of blood causes slight increase of pressure

aorta and large arteries are what in response to pressure?

pressure reservoirs, stores energy in systole as walls expand and release in diastole as walls recoil

End diastolic volume (EDV)

volume of blood in ventricle at the end of diastole

End systolic volume (ESV)

volume of blood in ventricle at the end of systole

stroke volume (SV)

volume of blood ejected from ventricle each cycle