Neuromuscular junction

Fig. 11-12

Somatic motor neuron

Musclefiber

Theneuromuscularjunction

Motor end plateTerminalbouton

Mitochondria

Synaptic vesicle (ACh)

Presynapticmembrane

Synaptic cleft

Postsynapticmembrane

Schwann cell sheath

Axon terminal

Nicotinic AChreceptors

Neuromuscular junction

Fig. 11-13

Skeletal muscle

fiber

AChE

Voltage-gatedCa2+ channel

Action potential

ACh

Ca2+Ca2+

Acetyl + choline

Nicotinicreceptor

Motor endplate

Somatic motor neuron

Axon terminal

K+

Na+

Na+

K+

AChClosed channel Open channel

T-tubules and SR

Fig. 12-4

Sarcolemma

Thin filament

Thick filament

T-tubule brings actionpotentials into interiorof muscle fiber.

Sarcoplasmic reticulumstores Ca2+

Excitation-contraction coupling

Axon terminal ofsomatic motor neuron

Myosin head

Myosin thick filament

M line

Motor end plate

Sarcoplasmicreticulum

ACh

DHP

RyR

T-tubule

Muscle fiber

Troponin

TropomyosinActin

Z disk

Na+

Ca2+

Ca2+ released

Myosin thick filament

Fig. 12-11

Troponin and tropomyosin

Fig. 12-3

Thin filaments

Tropomyosin

Troponin

Actin chain G-actin molecule

Nebulin

Cross-bridge cycle

Fig. 12-9

ADP ADP

Actinmoves

Cytosolic Ca2+

Tropomyosin shifts,exposing bindingsite on actin

TN

Power stroke

Initiation of contraction

Troponin G-Actin

Tropomyosinblocks binding

site on actin

Myosin head

TN

Relaxed state. Myosin head cocked.

Pi

Pi

1

2 3

4

5

Types of Muscle Fibers

Fig. 12-15

SPINAL CORD

Neuron 1Neuron 2Neuron 3

Motornerve

Muscle fibers

Motor unit 2

Motor unit 1

Motor unit 3

One muscle may havemany motor units ofdifferent fiber types.

KEY

Motor Units

Fig. 12-15

Basic circulatory system

Fig. 9-2c, p.360

Peristaltic heart

One-way valves

Chambered Heart

Extrinsic Muscle Pump

Extrinsic muscle

Blood

Valve

Blood vessel structure

Fig. 15-2

Schematic view of mammalian circulation

Mammalian circulation

Fig. 14-1

External anatomy of the heart

Superiorvena cava

Rightatrium

Auricle ofleft atrium

Aorta

Pulmonaryartery

Rightventricle

Leftventricle

Coronaryarteryand vein

Fig. 14-7

Internal anatomy of the heart

Right atrium Left atrium

Pulmonarysemilunar valve

Rightpulmonary

arteries

Right ventricle

Superiorvena cava

Left pulmonaryarteries

Aorta

Left pulmonaryveins

Cusp of the AV(bicuspid) valve

Cusp of a right AV(tricuspid) valve

Chordae tendineae

Inferiorvena cava

Papillary muscles

Left ventricle

Descendingaorta

Fig. 14-7

Cardiac muscle structure

Intercalateddisks

Myocardial musclecell

Fig. 14-7

Intercalated discs