Teas Test Science Part 2

The neuromuscular system incorporates the nervous system and the muscular system and affects every part of the body daily functions and drive for homestasis Neurons pass information using an electrical nerve impulse. Info passes through hundreds of neurons much like a game of telephone until it reaches the final destination of a muscle for an action to be performed. Muscle cells carry out their function by their ability to contract.

Is to gather information from the internal and external environment and communicate any necessary changes to the muscular system

The nervous system is divided into the Central Nervous System (CNS) and the Peripheral Nervous System (PNS)

Consists of the brain and spinal cord The brain integrates sensory information received from the internal and external environment and assembles a motor response The spinal cord is similar to a multilane highway system that connects the peripheral nervous system to the brain

consists of the extensive network of spinal nerves carrying sensory or afferent information towards the spinal cord and brain and motor or efferent information away from the brain and spinal cord. The spinal nerves are the many side roads and alleys that go to every part of our body outside the CNS so the brain has access to everything that is going on in the body and can make decisions necessary to keep homeostatic balance via muscle reactions.

The peripheral motor nerves send efferent impulses to both somatic and autonomic divisions of the nervous system to carry out a response

The somatic division is voluntary and controls the skeletal muscles of the body -we can control our own body and muscles for movement and what not

also known as visceral division is involuntary and controls the visceral or cardiac muscles of organ systems like the digestive and cardiovascular systems without our conscious planning. -like when we swallow (somatic) we turn on the involuntary (autonomic) pathway for digestions.

The information gathered, processed, and passed to muscles travels as electrical impulses of the nervous system along specialized cells called neurons.

Includes a cell body, dendrites, and axons

the main part of the cell containing the nucleus and most organelles and nerve fibers that extend from the body

are nerve fibers Dendrites are receptor extensions that receive nerve impluses

are nerve fibers is a long singular tail-like extension, which sends impulses from the neuron body to the branching axon terminal

All nerve impulses travel in this one-way direction: from dendrites to the cell body and then down the axon. A stimulus is picked up at the dendrites and sent through the cell body and along the axon to terminal branches. Once the nerve impulse reaches the axon terminal it stimulates the release of chemical neurotransmitters into a gap structure known as the synapse. The synapse is the structure that allows neurons to pass signals on to other neurons, muscles, or glands. Sensory neurons carry afferent impulses towards the CNS, and motor neurons carry efferent impulses from the CNS out to muscles.

are bundles of nerve fibers axons and dendrites and therefore contain both afferent and efferent impulses. when an efferent axon terminal synapses with a muscle cell, the stimulation of a muscle contraction can occur.

Muscles are fibrous tissue with the unique ability to shorten or contract to move body parts and then unflex Muscles consists with a bundle of muscle fibers and these muscle fibers contain countless of smaller myofibrils

Have two types of contractile protein filaments: the thinner actin and thicker myosin These contractile protein filaments are arranged in overlapping bands. A sarcomere is the repeating contractile unit of a skeletal muscle and is delineated by these bands of myosin and actin filaments.

When the axon terminal secretes the chemical neurotransmitter at the synapse of a neuromuscular junction, it stimulates the muscle to contract. Contraction occurs when the thin actin filaments slide past the thicker myosin filaments, causing the sarcomere unit to shorten or contract. -The myosin or the actin dont shorten themselves but the length of the sarcomere by sliding past one another

ATP, the chemical energy of all cells, is used to cause the contraction and is also necessary for the relaxation of the muscle Many muscle fibers must contract in a unified pattern to cause a fluid muscle contraction for movement of a body part.

In the somatic system, the fine motor control used in hand and eye muscles requires connections of three to six muscle fibers per neuron For powerful contractions of leg or arm movements there can be connections of 1000 muscle fibers per neuron

The autonomic division of the neuromuscular system controls the contraction and relaxation of visceral reflexes The rate and depth of the heartbeat by cardiac muscles and the mechanical propulsions and breakdown of food through the digestive system are both examples of neuromuscular control by Autonomic nervous system

can involve both the nervous and muscle systems muscle response to nerve impulse can be affected by an injury to the muscle and/or its supporting ligaments and tendons

the neuromuscular junction is compromised in a condition called amyotrophic lateral sclerosis also known as Lou Gehrig’s disease The motor neurons degenerate and die, leading to loss of voluntary muscle movement

is a group of genetic disorders in which abnormal genes interfere with the production of proteins needed to form healthy muscle While the nerves are not affected in muscular dystrophy, muscles progressively degenerate and weaken. BOTH VOLUNTARY AND INVOLUNTARY MUSCLES ARE COMPROMISED unlike ALS