anatomy ch6

Smooth muscle

Involuntary, visceral, nonstriated muscle found in the walls of hollow organs such as intestines and blood vessels

Cardiac muscle

Involuntary striated muscle found in the heart, responsible for pumping blood throughout the body.

Sarcolemma

The thin, transparent membrane surrounding each muscle fiber that contains the muscle cell's content.

Myofibril

Long, thread-like structures in muscle fibers that are made of myofilaments, crucial for muscle contraction.

Sarcomere

The basic contractile unit of striated muscle fibers, consisting of a repeating pattern of myofilaments.

Myofilament

The protein filaments (thick and thin) that make up myofibrils, crucial for muscle contraction.

Cardiac muscle

Involuntary striated muscle found in the heart.

Skeletal muscle

Voluntary muscle responsible for body movement, attached to bones.

Myofibril

Long, thread-like structures in muscle fibers that are made of myofilaments.

Thick filaments

Protiens, primarily myosin, responsible for muscle contraction.

Thin filaments

Proteins, primarily actin, that work with thick filaments for muscle contraction.

Neurotransmitter

Chemical messengers that transmit signals across a synapse.

Acetylcholine (ACh)

The neurotransmitter used at neuromuscular junctions to trigger muscle contraction.

Muscle fibers

Single muscle cells that make up muscle tissue and are responsible for contraction.

Skeletal muscle fibers

Type of striated muscle fibers that are under voluntary control, primarily found in muscles attached to bones.

Striated muscle

A type of muscle characterized by its striped appearance, found in skeletal and cardiac muscles.

Voluntary muscle

Muscle that is consciously controlled, such as skeletal muscle.

Perimysium

Connective tissue that surrounds a fascicle of muscle fibers.

Fascicle

A bundle of muscle fibers surrounded by perimysium.

Epimysium

The outer connective tissue layer that surrounds an entire muscle.

Tendon

A fibrous connection between muscle and bone, allowing for movement.

Aponeurosis

A flattened sheet of connective tissue that connects muscle to muscle or muscle to bone.

Actin

A protein that forms thin filaments in muscle fibers and plays a key role in muscle contraction.

Myosin

A motor protein that forms thick filaments and interacts with actin for muscle contraction.

Cross bridges

Connections formed between myosin heads and actin during muscle contraction.

Motor unit

A single motor neuron and the muscle fibers it innervates.

Axon

The long projection of a neuron that conducts electrical impulses away from the neuron.

Axon terminals

Branches at the end of an axon that connect to muscle fibers to transmit signals.

Neuromuscular junctions

Specialized synapses where motor neurons communicate with muscle fibers.

Synaptic cleft

The small gap between the axon terminal and the muscle fiber membrane at the neuromuscular junction.

Sarcoplasmic reticulum

A storage site for calcium ions that regulate muscle contraction.