Chapter 13.1-13.4

What is electrical activity of the heart

contracts the heart

what is heart rate determined by

fastest paced fibers

what is the semilunar valve?

regulate blood flow out of the heart into the aorta

what is the myocardium

(middle) -cardiomyocytes -cardiac muscle cells

What is the atrioventricular valve?

-AV valves lie between the atria and teh ventricles. Right AV vale - -Tricuspid. Left AV - Mitrial, Bicuspid. -AV Vales prevent backflow into the atria when ventricles contract. Chordae tendineae anchor AV valves to papillary muscles. **Try before you Buy**

how is heart rate controlled by pacemaker cells

-auto-rhythmic cells have pacemaker (conducting cells) potentials -spontaneous depolarization caused by closing K channels and opening two types of channels -depolarization to threshold -repolarization

What are the functions of the cardiovascular system?

-gas exchange -nutrients to tissues -get waste away from tissues -immune function transport of hormones

what is extra contraction

-premature atrial contraction (PAC) followed by a extra ventricular contraction -jamming in extra heart rates -ectopic firing of the atria (makes ventricle contract again when its not supposed to ) -premature atrial contraction

how is excitation coupling in cardiac similar to smooth muscle

-sooth uses Ca for contraction but relies mostly on extracellular Ca where cardiac uses some extracellular and some SR -cardiac has gap junctions

what is the advantage of parallel blood flow?

-there are ways around the "issue" to get blood to other parts of the body -regulates blood flow to tissues

what are the 5 phases of cardiac contractile cells

0: depolarization -increase Na permeability 1: decrease Na -dip back down (brief repolarization) 2: increase Ca permeability -slight increase in K -plateau 3: repolarization -Ca decreased -uptake of K 4: resting membrane potential -stable potential

what are the steps to initiation and conduction of an impulse

1. AP initiated in the SA node 2. signal travels to the interatrial and internodal via inter-nodal pathway 3. atrioventricular node to the bundle of His 4. bundle branches (bundle of His splits in 2) 5. purkinje fibers witch run back up the walls

what are the 5 types of blood vessels

1. Arteries 2. Arterioles 3. Capillaries 4. Venules 5. Veins

decrease HR steps

1. activate ACh 2. bind to muscarinic receptor 3. can increase K channel permeability (more ions in) -decrease potential 4. close Ca channels -less positive coming in 5. drop lower than normal (overcome more before firing again) -longer to depolarize

what are the excitation coupling steps

1. depolarize of cells to threshold through gap junctions 2. open Ca channels in plasma membrane for extracellular Ca -help open SR channels 3. AP travels down T tubules 4. Ca is released from SR 5. calcium binds to troponin 6. etc.. same as skeletal muscle

to increase HR steps

1. epinephrine (adrenal) and norepinephrine (sympathetic) bind to beta 1 receptor 2. activation of Na and Ca channels 3. greater influx of sodium and Ca which increase depolarization 4. pacemaker potentials will happen faster

what are the functions of valves

1. maintain unidirectional blood flow -normal direction of flow 2. mechanism that drives blood flow -pressure: high to low 3. valve open and close based on: pressure -passive process

what are the two circuits of blood flow

1. pulmonary 2.coronary

Steps of excitation relaxation

1. remove Ca from cytosol 2. troponin and tropomyosin returns to their position covering myosin binding sites on actin 3. same as skeletal but some Ca is pumped out of the cell

pulmonary veins

Deliver oxygen rich blood from the lungs to the left atrium -splits in two

what is a recording of the heart called

ECG -can be recored from electrodes on the skin -noninvasive

What is the superior and inferior vena cava?

It brings blood from the upper/lower body to the heart.

What is the semilunar valve?

Prevents back flow of blood into the ventricles

what is ischemia

ST intervals is under everything (depressed -insufficient blood flow

what two things are involved in increasing HR

Sympathetic and adrenal medulla

why is the heart a closed system

all blood is contained within vessels

what is the P wave

atrial depolarization

SQ segment

atrial relaxation

bicuspid (mitral) valve

between left atrium and left ventricle

What are platelets?

blood clotting -stop blood loss then repair

what are the capillaries function

bring O2 and remove waste

how do you test for abnormalities in HR

by looking at sinus rhythms on ECG

what is a atrial fibrillation ECG look like

can live with this with meds or a pacemaker

what does a ventricular fibrillation ECG look like

cannot live with (dead) -"code" -ventricles are filling at random and this "flutters the heart" -no real contraction

How is excitation coupling in cardiac similar to skeletal

cardiac cells have T-tubules too -Ca is from the SR and some from extracellular but skeletal muscles only have Ca come from SR -Cardio looks like skeletal muscle set up

what are capillary muscles and what do they do

cardiac tendineae -help to keep valves shut when ventricles contract

whats the difference between cardiac contraction and skeletal contraction

cardiac: long refactory, short contractile -250-300 msec skeletal: long contraction, short refractory -1-2 msec

What does the aorta do?

carries blood from the left ventricle to the body -expands when blood flows in like a balloon -works through diastol -aorta goes back to normal: blood flows in both directs (blood that flows backwards goes to coronary arteries)

what are arteries function

carry blood away from the heart -all oxygenated except for the pulmonary artery

where is the heart located

center mass -size of fist -tilted, bottom points to the left

What is pulmonary circulation?

circulation between heart and lungs -right atrium -> right ventricle -> pulmonary artery -> lungs -> pulmonary vein -> left atrium -> left ventricle -> aorta -oxygenated blood -goes through body circuit where exchange occurs

ST interval

contracting

what is the PQ interval

depolarization of the atrium and contraction

What is the pericardium?

double-walled sac that encloses the heart -very outside

What are formed elements?

erythrocytes, leukocytes, platelets

What is tachycardia?

fast heart rate -from inverted T waves with lots of QRS complexes - can mean heart block (bundle branch block)

What is coronary circulation?

flow of blood to and from the tissues of the heart -parallel -heart has own set of capillaries -blood circulation to the heart -through coronary arteries -capillaries are supplied by coronary arteries (left to right) that arise from the aorta

what is in parallel blood flow

go from A to B and then branch in two directions to go to both C and D -to get to different parts faster

what are nodes

grouping of pacemaker cells

what is a myocardial infarction

heart attack -elevated ST segment

what are Leukocytes

immune cells

what is the endocardium

inner lining of the heart -endothelial cells

what is plasma

liquid portion of blood and everything disolved in it

aortic semilunar valve

located between the left ventricle and the aorta

cardiac contraction

long duration (250-300 msec) -longer refractory period than contractile period -must relax to continue to pump blood if no relaxation it will never fill with blood

what is the diaphragm

muscle under the rib cage involved in breathing -separates thoracic from abdominal cavity

What is the epicardium?

outer two layers of the heart

what is in series blood flow

overall flow -flow from a to b to c...

what are erythrocytes

oxygen carrying red blood cells -gas extange

What are autorhythmic cells?

pacemaker cells -make rhythm of the heart -provide pathway . for passing current through the heart tissues

graph of pacemaker

pacemaker potential: decrease K Increase Na depolarization: increase Ca Peak: decrease K repolarization: increase K

what two things are involved in decreasing HR

parasympathetic and vagus nerve stimulation

Are valves active or passive?

passive

conduction fibers

rapidly conduct action potentials initiated by pacemaker cells to myocardium -all cardiomyocyte based but no contractile ability (modified heart cells)

what are arterioles function

responsible for regulating blood pressure - high resistance to blood flow- based on large vasomotion -large change in size

pulmonary semilunar valve

right ventricle to pulmonary artery

what are the two layers of the epicardium and their functions

serious: membrane on the outside surrounding but not touching (inner) fibrous: outermost layer of the heart (protective layer of the heart) (outermost)

what are intercalated discs

sets of desmosomes (cannot pull away from each other)

what are the rates of each node/branch/pathway

sinoatrial node (SA): fastest 70-80 atrioventricular node (AV): 40-60 internodal pathway: 20-40 interatrial pathway: 20-40 bundle of His: 20-40 bundle banches: 20-40 purkinje fibers: 20-40

what is brachycardia

slow HR -not always bad -athletes have this from training

what are veins functions

some musculature -motion -smushed / not as good of a shape as arteries

What are pacemaker cells?

specialized cells of the electrical conduction system of the heart -set rhythm -spontaneous depolarization -no stimulus to cause AP -leak ions - sodium in particular

what is the conduction pathway of the heart

spread of excitation between the cells -gap junctions -atria contract --> ventricle contract

what are the venules function

start bringing blood back to the heart -look like veins/capillaries -thin walls -little to no musculature -cannot change size

what is autorhythmicity

the ability to generate own rhythm

tricuspid valve

valve between the right atrium and the right ventricle

when the heart contracts does the atriums or ventricles have higher pressure

ventricles (the one that just received blood)

What is the QRS complex?

ventricular depolarization -atrial repolarization

QT interval

ventricular relaxation

T wave

ventricular repolarization

what is third degree heart block

(Complete heart block) the atria and ventricles are paced independently and there is no relationship between the P waves and QRS complex

what is the direction of blood flow through vessels

1. arteries 2. arterioles 3. capillaries 4. venules 5. veins

what are the two ways blood flows?

1. in series 2. in parellel