Untitled Flashcards Set

Structural Classification of Joints: Fibrous

Joints connected by dense connective tissue; example: sutures in the skull.

Structural Classification of Joints: Cartilaginous

Joints where bones are connected by cartilage; example: intervertebral discs.

Structural Classification of Joints: Synovial

Joints with a fluid-filled joint cavity; example: knee joint.

Functional Classification of Joints: Synarthrosis

Immovable joints; example: sutures in the skull.

Functional Classification of Joints: Amphiarthrosis

Slightly movable joints; example: pubic symphysis.

Functional Classification of Joints: Diarthrosis

Freely movable joints; example: shoulder joint.

Factors Influencing Joint Stability: Shape of the Articular Surfaces

How well the joint surfaces interdigitate affects stability.

Factors Influencing Joint Stability: Ligament Strength

Stronger ligaments contribute to greater stability.

Factors Influencing Joint Stability: Muscle Tone

Increased muscle tone around a joint enhances stability; most important factor.

Types of Angular Movements: Flexion

Decreasing the angle between body parts; moves along the sagittal plane; example: bending the elbow.

Types of Angular Movements: Extension

Increasing the angle between body parts; moves along the sagittal plane; example: straightening the elbow.

Types of Angular Movements: Abduction

Moving away from the midline; moves along the frontal plane; example: raising arms sideways.

Types of Angular Movements: Adduction

Moving toward the midline; moves along the frontal plane; example: lowering arms to the sides.

Types of Angular Movements: Circumduction

Circular movement at a joint; moves along the frontal and transverse planes; example: moving the arm in a circular motion.

Types of Rotation: Medial Rotation

Rotating towards the body's midline; example: turning the shoulder inward.

Types of Rotation: Lateral Rotation

Rotating away from the body's midline; example: turning the shoulder outward.

Types of Special Movements: Elevation

Raising a body part; example: shrugging shoulders.

Types of Special Movements: Depression

Lowering a body part; example: returning shoulders to normal position.

Types of Special Movements: Pronation

Turning the palm downward; example: rotating the forearm.

Types of Special Movements: Supination

Turning the palm upward; example: rotating the forearm to face up.

Types of Special Movements: Opposition

Moving the thumb to touch fingertips; example: grasping an object.

Rotator Cuff Tendons

Four tendons that stabilize the shoulder joint; important for shoulder stability and movement.

Glenoid Labrum

Cartilaginous rim around the glenoid cavity of the shoulder; adds stability.

Sensory vs Motor

Sensory nerves transmit signals to the CNS; motor nerves transmit signals from the CNS.

Somatic vs Visceral

Somatic refers to voluntary muscle control; visceral pertains to involuntary functions.

CNS vs PNS

CNS (Central Nervous System) includes the brain and spinal cord; PNS (Peripheral Nervous System) consists of nerves outside the CNS.

Neuroglia of CNS: Astrocytes

Support neurons and maintain blood-brain barrier.

Neuroglia of PNS: Schwann Cells

Form myelin sheaths around peripheral nerves.

Parts of a Neuron: Dendrites

Receive incoming signals; typically branching extensions.

Parts of a Neuron: Axon

Transmits electrical impulses away from the cell body; long and slender.

Parts of a Neuron: Cell Body

Contains nucleus and organelles; the neuron's metabolic center.

Ionic Composition of Resting Membrane Potential: Na+ and K+

High extracellular Na+, high intracellular K+ contribute to a membrane potential of approximately -70 mV.

Graded Potentials

Localized changes in membrane potential that vary in strength; can lead to action potentials.

EPSPs (Excitatory Postsynaptic Potentials)

Positive change in membrane potential caused by influx of Na+; brings neuron closer to firing.

IPSPs (Inhibitory Postsynaptic Potentials)

Negative change in membrane potential caused by influx of Cl-; moves neuron away from firing.

Sequence of Steps to an Action Potential

1) Depolarization; 2) Repolarization; 3) Hyperpolarization.

Absolute Refractory Period

Period during which no new action potential can be initiated due to Na+ channel inactivation; occurs during depolarization.

Relative Refractory Period

Period during which a stronger-than-normal stimulus can initiate another action potential; occurs during repolarization.

Synapse Definition

Functional junction between two neurons; information flows from presynaptic to postsynaptic neuron.

Chemical Synapse vs Electrical Synapse

Chemical synapses use neurotransmitters and are slower; electrical synapses are faster and involve direct current flow.

Stimulus Intensity Coding

Coding of stimulus strength by frequency of action potentials; stronger stimuli increase presynaptic activity.

General Steps of a Chemical Synapse

1) Action potential arrives; 2) Ca2+ channels open; 3) Neurotransmitter release; 4) Binding to receptors on postsynaptic neuron.

Temporal Summation vs Spatial Summation

Temporal summation involves multiple signals at one synapse; spatial summation involves multiple signals at several synapses.

Types of Skeletal Muscles: Striated/Muscle Types

Skeletal and cardiac muscles are striated; smooth muscles are involuntary; skeletal muscle fibers have multiple nuclei.

Striations in Muscles

Produced by the arrangement of myofilaments (actin and myosin) in a repeating pattern.

Components of a Muscle: Epimysium, Perimysium, Endomysium

Epimysium surrounds the entire muscle; perimysium surrounds fascicles; endomysium surrounds individual muscle fibers.

Muscle vs Fascicle vs Muscle Fiber vs Myofibril vs Myofilaments

Muscle is composed of fascicles; fascicles contain muscle fibers; muscle fibers contain myofibrils; myofibrils contain myofilaments (actin and myosin).

Sarcolemma

The plasma membrane of muscle fibers that conducts electrical signals.

T-tubules

Extensions of the sarcolemma that allow depolarization to reach deep into the muscle fibers.

Sarcoplasmic Reticulum

Specialized endoplasmic reticulum in muscle cells; stores calcium ions.

Thick and Thin Filaments

Thick filaments are primarily myosin; thin filaments are primarily actin; troponin and tropomyosin are associated with thin filaments.

Sarcomere Definition

The basic contractile unit of a muscle; defined by Z-lines.

NMJ (Neuromuscular Junction) Function

Calcium enters the axon terminal, triggering ACh release; ACh binds to receptors on muscle, leading to contraction.

End Plate Potential

Local depolarization of the muscle fiber membrane at the neuromuscular junction.

T-tubule Proteins Change Shape

Triggering of action potentials causes these proteins to change shape, leading to SR releasing calcium.

Troponin and Tropomyosin Movement

Calcium binds to troponin, shifting tropomyosin and exposing binding sites for myosin on actin.

Cross-Bridge Cycle Steps

Myosin heads attach to actin, pull, detach, and return to resting state; ATP is needed for detachment.

Motor Unit Definition

A single motor neuron and all the muscle fibers it innervates; more fibers lead to less control.

Phases of a Muscle Twitch

1) Latent period; 2) Contraction period; 3) Relaxation period; duration varies by fiber type.

Temporal Summation Definition

Increased force of muscle contraction due to successive stimuli; can lead to unfused or fused tetanus.

Differences Between Isotonic and Isometric Contractions

Isotonic contractions involve changes in muscle length; isometric contractions generate tension without changing length.

ATP Regeneration Pathways

1) Direct phosphorylation (creatine phosphate); 2) Anaerobic respiration (glycolysis); 3) Aerobic respiration (oxidative phosphorylation).

ATP Pathway Characteristics

Direct phosphorylation is fast and no oxygen used; anaerobic respiration is quick but produces lactic acid; aerobic respiration is efficient but slow.

Types of Muscle Fibers

Fast-twitch (white) fibers are suited for sprinting; slow-twitch (red) fibers are suited for endurance.

Energy Pathway Duration

Short-duration high-intensity uses anaerobic pathways; prolonged duration relies on aerobic pathways.