17.4 Chapter Human Structure and Function

Which ventricular wall is thicker

Left ventricle thicker myocardium, can generate more pressure and more powerful pump, Must pump blood to all body tissues,

Skeletal vs Cardiac: strcuture

Skeletal: striated, long, cylindrical, multinucleate Cardiac: Striated, short, branched, one or two nuclei

Skeletal vs Cardiac: gap junctions

Skeletal: no, Cardiac: have gap junctions

Skeletal vs Cardiac: contraction

Skeletal: motor units stimulated individually, Cardiac: gap junctions create functional syncytium, contract as a unit

Skeletal vs Cardiac: SR

Skeletal: elaborate SR, has terminal cisterns Cardiac: simple SR, no terminal cisterns

Skeletal vs Cardiac: Calcium source

Skeletal: SR only source of calcium, Cardiac: SR and extracellular fluid sources of calcium

Skeletal vs Cardiac: calcium bind

Skeletal: Calcium binds to troponin, Cardiac: calcium binds to troponin

Skeletal vs Cardiac: pacemaker cells

Skeletal: no pacemaker cells present, Cardiac: has pacemaker cells

Skeletal vs Cardiac: tetanus

Skeletal: tetanus is possible, Cardiac: tetanus is not possible

Skeletal vs Cardiac: ATP

Skeletal: get ATP from aerobic and anaerobic respiration, fewer mitochondria Cardiac: get ATP only from aerobic respiration, more mitochondria

Intercalated discs

junctions with desmosomes and gap junctions, where plasma membranes of adjacent cells interlock

Desmosomes function in intercalated disc

Prevent adjacent cells from separating during contraction

Gap junction function in intercalated discs

Allow ions to pass from cell to cell