STUDY SET #3 - Ch. 10 Muscle, Ch. 13 Nervous Tissue 💛

Muscular system

Consists only of skeletal muscles

Myology

The study of muscles

Functions of muscle tissue

Movement of body parts and contents, communication, stability, posture, control of body openings, heat production, and glycemic control

Excitability

The ability of muscle cells to respond to chemical signals, stretch, and electrical changes

Conductivity

The ability to propagate electrical signals along the muscle cell membrane

Contractility

The ability of muscle cells to shorten forcefully when stimulated

Extensibility

The ability of muscle cells to stretch without damage

Elasticity

The ability of muscle cells to return to original length after contraction

Skeletal muscle

Voluntary, striated muscle usually attached to bones

Cardiac muscle

Involuntary, striated muscle found only in the heart

Smooth muscle

Involuntary, nonstriated muscle found in viscera

Muscle fiber

A muscle cell

Sarcolemma

Plasma membrane of a muscle fiber

Sarcoplasm

Cytoplasm of a muscle fiber

Myofibrils

Cylindrical bundles of myofilaments that fill the sarcoplasm

Sarcoplasmic reticulum

Specialized smooth ER that stores calcium ions

Transverse (T) tubules

Invaginations of the sarcolemma that conduct action potentials into the fiber

Myoglobin

Oxygen-binding protein that gives muscle its red color

Myofilaments

Protein filaments responsible for muscle contraction

Thick filaments

Composed primarily of myosin

Thin filaments

Composed primarily of actin, troponin, and tropomyosin

Myosin

Motor protein with projecting heads that bind actin

Actin

Protein forming the backbone of thin filaments

Tropomyosin

Protein that blocks myosin-binding sites on actin

Troponin

Protein that binds calcium and shifts tropomyosin

Titin

Elastic protein that anchors thick filaments to Z discs

Striations

Alternating dark and light bands seen in skeletal and cardiac muscle

A band

Dark band representing the full length of thick filaments

I band

Light band containing thin filaments only

Z disc

Boundary between adjacent sarcomeres

Sarcomere

Smallest functional contractile unit of muscle

Neuromuscular junction

Synapse between a motor neuron and a muscle fiber

Acetylcholine (ACh)

Neurotransmitter released by motor neurons

Motor unit

One motor neuron and all the muscle fibers it innervates

Excitation-contraction coupling

Sequence linking muscle excitation to contraction

Power stroke

Pivoting of myosin heads that pulls thin filaments

Relaxation

Process in which calcium is pumped back into the sarcoplasmic reticulum

Slow oxidative fibers

Type I fibers that are fatigue resistant and use aerobic respiration

Fast glycolytic fibers

Type II fibers that fatigue quickly and rely on anaerobic metabolism

Muscle hypertrophy

Increase in muscle fiber size due to increased myofilaments

Muscle atrophy

Decrease in muscle size due to disuse or denervation

Neurobiology

The study of the nervous system

Nervous system

System specialized for sensory perception, integration, and motor control

Central nervous system (CNS)

Brain and spinal cord

Peripheral nervous system (PNS)

Nerves and ganglia outside the CNS

Neuron

Nerve cell specialized for rapid electrical communication

Excitability

Ability of neurons to respond to stimuli

Conductivity

Ability of neurons to transmit electrical signals

Secretion

Ability of neurons to release neurotransmitters

Sensory (afferent) neurons

Detect stimuli and transmit information to the CNS

Interneurons

Receive signals from other neurons and process information

Motor (efferent) neurons

Transmit signals from the CNS to muscles and glands

Neurosoma (cell body)

Control center of the neuron

Chromatophilic substance (Nissl bodies)

Rough ER of neurons

Dendrites

Receive incoming signals from other neurons

Axon

Conducts action potentials away from the neurosoma

Terminal arborization

Branched distal end of an axon

Axon terminals

Release neurotransmitters to target cells

Multipolar neuron

One axon and many dendrites

Bipolar neuron

One axon and one dendrite

Unipolar neuron

Single process extending from the cell body

Neuroglia

Supportive cells of nervous tissue

Oligodendrocytes

Form myelin sheaths around CNS axons

Schwann cells

Form myelin sheaths around PNS axons

Myelin sheath

Insulating layer that increases conduction speed

Nodes of Ranvier

Gaps between myelin segments

Saltatory conduction

Rapid conduction of action potentials from node to node

Astrocytes

Provide structural and metabolic support to neurons

Microglia

Phagocytic cells providing immune defense

Ependymal cells

Line ventricles and circulate cerebrospinal fluid

Satellite cells

Support neurons in peripheral ganglia

Synapse

Junction where a neuron communicates with another cell

Chemical synapse

Synapse using neurotransmitter release

Electrical synapse

Synapse using gap junctions for ion flow

Neurotransmitter

Chemical messenger released at synapses

Excitatory synapse

Increases likelihood of postsynaptic action potential

Inhibitory synapse

Decreases likelihood of postsynaptic action potential

Nerve regeneration

Regrowth of damaged PNS axons if the cell body remains intact

Neurulation

Formation of the neural tube during embryonic development