Lect4 BIOSCI

Muscle Tissue

Consists of elongated cells (myocytes) that use energy from ATP hydrolysis to generate force for body movements, posture, and heat.

Skeletal Muscle

Type of muscle tissue that is striated, multinucleate, and under voluntary control; attached to bones and involved in body movement.

Cardiac Muscle

Striated and branched muscle tissue found in the heart with a single central nucleus; involuntary control.

Smooth Muscle

Non-striated muscle tissue located in the walls of hollow internal structures; involuntary control.

Myofibrils

The contractile threads found in striated muscle cells, composed of thick and thin myofilaments organized into sarcomeres.

Sarcomere

The basic functional unit of a myofibril, defined by Z discs; composed of thick (myosin) and thin (actin) filaments.

Neuroglia

Supporting cells of the nervous system that do not propagate action potentials but assist neurons in various functions.

Neuron

A nerve cell that transmits nerve impulses; consists of a cell body, dendrites, and an axon.

Dendrites

Short, branched extensions of a neuron that receive signals and convey impulse to the cell body.

Axon

The elongated part of a neuron that transmits nerve impulses away from the cell body to other neurons or tissues.

Oligodendrocytes

CNS neuroglia that form the myelin sheath around axons, speeding up action potentials.

Schwann Cells

PNS neuroglia that form myelin sheaths around myelinated axons or support non-myelinated axons.

Satellite Cells

PNS neuroglia that surround neuron cell bodies, regulating the environment around the neurons.

Astrocytes

Star-shaped neuroglia in the CNS that support and repair neurons, maintain the blood-brain barrier, and regulate ion balance.

Ependymal Cells

CNS neuroglia that line ventricles and produce cerebrospinal fluid.

Myofilaments

Thin (actin) and thick (myosin) filaments that make up myofibrils, responsible for muscle contraction.

Gap Junctions

Specialized cell-cell contacts in cardiac muscle that enable rapid communication between cells.

Homeostasis

The maintenance of stable internal conditions in the body, regulated by the nervous and endocrine systems.