Bio 11 - Anatomy - heart, circulation, cardiovascular system

for Terry Lopez' class

Cardiac Muscle Tissue

cells are striated, short, interconnected; 1-2 nuclei

T-tubules wide, less numerous. SR simpler than skeletal muscle

large mitochondria = 25-35% cell volume

Intercalated Discs

junctions between cells; anchor

Desmosomes

prevent cell from separating during contraction

Gap Junctions

allow ions to pass from cell to cell, electrically couple adjacent cells

Pacemaker Cells

noncontractile cells that spontaneously depolarize 

Fibrillation

rapid irregular contractions - heart becomes useless for pumping blood → circulation stops, may result in brain death

Defibrillation

“clean slate,” interrupts chaotic twitching to start regular depolarizations

Medulla Oblongata

heartbeat modified by autonomic nervous system via cardiac centers

Cardioacceleratory Center

sends signals through sympathetic trunk to increase rate and force;

stimulates sinoatrial and atrioventricular nodes via vagus nerve

Sympathetic

increases rate and force of contraction

Parasympathetic

decreases rate of contraction

P Wave

depolarization of SA node → Atria

QRS Complex

ventricular depolarization and atrial repolarization

T Wave

ventricular repolarization

Junctional Rythm

Sinoatrial node nonfunctional. P-waves absent, 40-60 BPM

Second Degree Heart Block

AV node fails to conduct some SA node impulses

~2 P waves per 1 QRS complex

Ventricular Fibrillation

Electrical activity disorganized, random action potentials. 

Systole

contraction of a chamber

Diastole

relaxation of chamber

Atrioventricular Valves

(2) closure causes first “lubb”

Semilunar Valves

(2) at base of great arteries; closure causes second “dupp”

Ventricular Systole

ventricles contract, semilunar valves open, AV valves close “lubb”

Ventricular Diastole

ventricles relax and fill with blood, atrioventricular valves open, semilunar valves close “dupp”

Systolic Pressure

pressure exerted in aorta during ventricular contraction

Diastolic Pressure

lowest level of aortic pressure when heart is at rest

Right Atrium

receives blood returning from systemic circuit

Left Atrium

receives blood returning from pulmonary circuit

Right Ventricle

pumps blood through pulmonary circuit

Left Ventricle

pumps blood through systemic circuit

Serous Pericardium

parietal layer, visceral layer, and cavity of heart