CSCS chapter 1

Alveolar pressure

Pressure inside the alveoli when the glottis is open and no air is flowing into or out of the lungs.

Bone periosteum

A specialized connective tissue covering all bones; tendons attach to the bone periosteum.

Bradycardia

Heart rate less than 60 bpm.

Bronchi

Second generation passages in the respiratory system that deliver air to the bronchioles.

Bronchiole

Third generation passages in the lungs that deliver air to the alveoli where gases are exchanged.

Capillary

Small end tubes of the arterial system that facilitate exchange of oxygen, fluid, nutrients, and other substances between blood and tissues.

Cartilaginous joints

Joints that allow limited movement such as intervertebral disks.

A Band

Section of the sarcomere corresponding with alignment of myosin and actin filaments.

Acetylcholine

Neurotransmitter released when an action potential arrives at the nerve terminal, diffuses across the neuromuscular junction, and excites the sarcolemma.

Actin

Protein forming actin myofilaments consisting of two thin strands arranged in a double helix.

Action potential

Electrical impulse from a motor nerve that triggers calcium release from the sarcoplasmic reticulum causing muscle tension.

All or none principle

A motor neuron stimulus causes all fibers in that motor unit to contract with no partial response.

Alveoli

Final passages in the respiratory system where gas exchange occurs.

Aortic valve

Valve preventing backflow of blood from the aorta into the ventricle.

Appendicular skeleton

Bones of the limbs, pectoral girdle, and pelvic girdle.

Arterial system

Tubes carrying blood away from the heart under high pressure.

Arteriole

Small branches of arteries delivering blood to capillaries.

Artery

Strong tubes that rapidly transport blood from the heart.

Atrioventricular bundle

Conducts cardiac impulse to the ventricles.

Atrioventricular node

Delays impulse from the SA node before ventricular contraction.

Atrioventricular valves

One way valves preventing backflow from ventricles to atria.

Atrium

Heart chambers that receive blood and pump it to the ventricles.

Axial skeleton

Bones of the skull, vertebral column, ribs, and sternum.

Biaxial joints

Joints allowing movement around two perpendicular axes such as wrist and ankle.

Crossbridge

Connection between myosin heads and actin that produces muscle force.

Depolarization

Reversal of heart membrane electrical potential causing contraction.

Diastole

Ventricular relaxation.

Diffusion

Random movement of gases across the alveolar capillary membrane.

Distal

Muscle attachment farther from the trunk.

Electrocardiogram ECG

Graphic representation of heart electrical activity.

Endomysium

Connective tissue surrounding each muscle fiber.

Extrafusal fibers

Normal muscle fibers.

Fasciculi

Bundles of muscle fibers surrounded by perimysium.

Fast twitch fiber

Fibers that contract rapidly and fatigue quickly including Type IIa and Type IIx.

Fibrous joint

Joints allowing little to no movement such as skull sutures.

Golgi tendon organ

Proprioceptor sensing muscle tension to protect against excessive force.

Hemoglobin

Iron containing protein in red blood cells that transports oxygen and buffers blood pH.

I Band

Region of the sarcomere containing only actin filaments.

Inferior

Trunk muscle attachment closer to the feet.

Intrafusal fiber

Modified fibers providing sensory information about muscle length.

Left bundle branch

Conducts cardiac impulse to the left ventricle.

Mitral valve

Prevents blood flow from left ventricle to left atrium.

Motor neuron

Nerve cell that innervates muscle fibers.

Motor unit

A motor neuron and all muscle fibers it innervates.

Multiaxial joints

Joints allowing movement around three axes such as shoulder and hip.

Muscle fiber

Long cylindrical multinucleated muscle cell with striations.

Muscle spindle

Proprioceptor sensing muscle length and rate of change.

Myocardium

Heart muscle tissue.

Myofibril

Contractile fibrils within muscle fibers.

Myofilament

Protein strands of actin or myosin responsible for contraction.

Myosin

Protein forming thick filaments with heads that bind actin to produce force.

Neuromuscular junction

Connection between motor neuron and muscle fiber.

Parasympathetic nervous system

Autonomic division that slows heart rate.

Perimysium

Connective tissue surrounding each muscle fascicle.

Pleura

Membranes surrounding the lungs and lining the chest wall.

Pleural pressure

Pressure between the lung pleura and chest wall pleura.

Power stroke

Pulling action during contraction caused by ATP hydrolysis.

Proprioceptor

Sensory receptor providing information about muscle and joint position.

Proximal

Muscle attachment closer to the trunk.

Pulmonary valve

Prevents backflow from pulmonary artery into right ventricle.

Purkinje fibers

Conduct electrical impulses throughout the ventricles.

P Wave

Electrical depolarization of the atria.

QRS Complex

Electrical depolarization causing ventricular contraction.

Red blood cell

Blood cell containing hemoglobin that transports oxygen.

Repolarization

Recovery phase following depolarization.

Right bundle branch

Conducts cardiac impulse to the right ventricle.

Sarcolemma

Membrane surrounding each muscle fiber.

Sarcomere

Smallest contractile unit of skeletal muscle.

Sarcoplasm

Cytoplasm of muscle fiber containing proteins and organelles.

Sarcoplasmic reticulum

Tubular network storing calcium ions.

Semilunar valves

Aortic and pulmonary valves.

Sinoatrial node

Primary pacemaker of the heart.

Sliding filament theory

Muscle shortens as actin slides over myosin.

Slow twitch fiber

Type I fibers with high aerobic efficiency and low force output.

Superior

Trunk muscle attachment closer to the head.

Sympathetic nervous system

Autonomic division that increases heart rate.

Synovial fluid

Fluid within joint capsule reducing friction.

Synovial joints

Freely movable joints such as elbow and knee.

Systole

Ventricular contraction.

Tachycardia

Heart rate above 100 beats per minute.

Tendon

Connective tissue attaching muscle to bone.

Tetanus

Sustained maximal muscle contraction from rapid stimulation.

Trachea

First respiratory passage delivering air to bronchi.

Tricuspid valve

Prevents blood flow from right ventricle to right atrium.

Tropomyosin

Protein blocking actin binding sites until calcium binds troponin.

Troponin

Protein that binds calcium to initiate contraction.

T tubule

Transverse tubules conducting action potentials deep into muscle fibers.

T wave

Electrical repolarization of ventricles.

Twitch

Brief muscle contraction following an action potential.

Type I fiber

Slow twitch fibers with high aerobic capacity and efficiency.

Type IIa fiber

Fast twitch fibers with moderate endurance and force.

Type IIx fiber

Fast twitch fibers with highest force and lowest endurance.

Uniaxial joints

Joints allowing movement around one axis such as the elbow.

Vein

Vessels returning blood to the heart.

Venous system

Tubes returning blood from tissues to the heart.

Ventricle

Heart chambers pumping blood to lungs or body.

Venule

Small vessels collecting blood from capillaries.

Vertebral column

Vertebrae separated by discs allowing movement and support.

Z line

Boundary of a sarcomere running through the I band.

Epimysium

Outer connective tissue layer surrounding skeletal muscle.