TEAS Science ~ Chapter 39 ~ Neuromuscular System

The neuromuscular system is a complex system that integrates

Muscles and nerves

The neuromuscular system affects every part of the body and is vital in controlling

Involuntary and Voluntary movements

Nerves are

Long bundles of axons

Nerve Function

Transmits signals from the central nervous system

The nerve signals start of as

Electrical impulses generated at the end of nerve cells

The nerves signals travel along the __________ and then is transmitted to the next cell using chemical neurotransmitters secreted into the __________ from the _______________

Axon; Synapse; Axon terminal

Parts of the neuron

Dendrites, Cell body, Axon, Myelin sheath, Axon terminal


Branchlike parts of a neuron that are specialized to receive information.

Cell body

Largest part of a typical neuron; contains the nucleus and much of the cytoplasm


The extension of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to muscles or glands

Myelin Sheath

A layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next.

Axon Terminal

The endpoint of a neuron where neurotransmitters are stored

Nerves send and receive signals in the:

Neuromuscular system

Sensory (Afferent) Nerves

Send messages to the central nervous system

Motor (Efferent) Nerves

Send messages out to the muscles (Away from the cns)

Autonomic (Involuntary) Nervous System

Controls involuntary actions involving cardiac and smooth muscle, such as heart rhythm, digestion, and breathing

Somatic (Voluntary) Nervous System

Conscious control of skeletal muscles. * Voluntary nerve signals make skeletal muscles do a deliberate action such as walking, throwing, or typing.

There are three types of Muscles:

Smooth, Skeletal, Cardiac

Skeletal Muscles

Often attach to bone and are involved in the movements of bones

Smooth Muscles

Can be found in the stomach, blood vessels, and intestines

Cardiac Muscles

Can be found in the heart

Parts of Muscles

Actin, Myosin, Sarcomere units

Muscles contain long myofibrils which are made of what?

Sarcomere units

Each sarcomere unit contains long strands of proteins called

Actin and Myosin

Sarcomere Unit Function

Basic contractile unit of muscle fibers; Allows a muscle cell to contract

Actin Filament Function

(Thin filament) Muscle contraction, cell motility, cell shape and support

Myosin Filament Function

(Thick Filament) Muscle contraction and cell motility

Each muscle fiber is connected to a

Nerve fiber

For the entire muscle to move it takes a concerted effort by many ___ and ____ and the use of ___ to power the contraction.

Nerves; Fibers; ATP

When a muscle is relaxed,

Myosin and actin filaments are not attached

When a muscle contracts

The filaments (myosin and actin) bind and are pulled together

Skeletal muscles work by


Contracting 1

* First the nervous system sends signal to the muscle

Contracting 2

* Actin and myosin proteins in the muscle slide past each other, creating either a contraction or relaxation of the muscles** These two basic motions are responsible for all muscle movements

Muscle Response

* Receptors in muscles allow them to receive a signal and respond with the appropriate magnitude and movement

The signal in motion response can be disrupted by disorder ranging from

Muscle strain, Muscle sprain, Muscular dystrophy

Which of the following actions is controlled by voluntary nerve signals?- Walking - Digestion - Heart beating - Breathing


Which of the following best describes the function of the nerve synapse

It allows for the passing of signals between neurons and muscles

Which of the muscle types of muscle cells are often voluntary


Which of the following types of nerves send messages to the brain


A person put their hands on something hot but quickly removes it. Describes the pathway of the signal and response through the neuromuscular system

Sensory Nerves → Brain → Motor Nerves → Hand