Anatomy & Physiology Semester 2 Final

Fascia

sheet of dense connective tissue that separates individual muscles and helps hold them in position

Epimysium

sheath of connective tissue that surrounds a skeletal muscle (beneath the fascia)

Perimysium

sheath of connective tissue that encloses a bundle of skeletal muscle fibers (fascicle)

Endomysium

sheath of connective tissue surrounding each skeletal muscle fiber

Tendon

cordlike connective tissue that connects muscle to bone

Tendinitis

inflammation of a tendon

Sprain

an injury to the ligament

Strain

an injury to a muscle or tendon

Skeletal muscle fiber

single cell that contracts (exerts a pulling force) in response to stimulation and relaxes when stimulation ends; also known as myofiber

Sarcolemma

the cell membrane in a muscle cell

Sarcoplasm

the cytoplasm in a muscle cell

Myofibril

contractile fiber in striated muscle cells that play a fundamental role in contractions

Sarcomere

structural unit of a myofibril and the functional unit of muscle contraction

Sarcoplasmic Reticulum

membranous network of channels and tubules within a muscle fiber; stores calcium ions

Transverse tubules

membranous channels that extend deep inward into the cell from the sarcolemma

Neuromuscular Junction

synapse between a motor neuron and a skeletal muscle fiber

Myosin

two twisted protein strands with globular heads; part of the thick filament

Actin

globular proteins with a binding site for myosin heads to attach; part of the thin filament

Troponin

complex of three proteins associated with tropomyosin

Tropomyosin

regulatory protein that blocks the myosin binding site on actin

Sliding Filament Model

the model for muscle contraction in which muscle proteins slide past each other to generate force

Rigor Mortis

the condition in which skeletal muscles partially contract and become rigid after death

Muscular Dystrophy

X-linked disorder caused by the mutation of the protein dystrophin; no anchoring of actin to the sarcolemma

Botulinum Toxin

neurotoxin produced by the bacteria clostridium bacterium; prevents fusion of acetylcholine to the cell membrane and leads to paralysis of muscles

Myasthenia Gravis

autoimmune disease caused by antibodies attaching ACh receptors on the sarcolemma; results in less muscle contraction

Creatine Phosphate

molecule in muscle that stores extra energy in phosphate bonds

Hemoglobin

oxygen-carrying protein in red blood cells

Myoglobin

oxygen-storing protein in muscle tissue

Oxygen Debt

the amount of oxygen that liver cells require, after anaerobic exercise, to convert the accumulated lactate into glucose, plus the amount muscle cells require to restore ATP and creatine phosphate to their original concentrations and return blood and tissue oxygen levels to normal

Fatigue

a condition where a muscle, after being exercised strenuously for an extended period, experiences a decreased ability to contract

Cramp

a painful condition in which a muscle undergoes a sustained involuntary contraction

Fast Twitch Fibers

fibers that fatigue easily, produce new filaments of actin & myosin and enlarge muscle fibers also known as white fibers

Slow Twitch Fibers

fibers that are fatigue resistant; develop more mitochondria & capillary networks; also known as red fibers

Muscular Hypertrophy

the enlargement of muscles that are forcefully exercised

Muscular Atrophy

the decrease in size and strength of an unused muscle

Twitch

single contraction of a muscle fiber followed by relaxation

Threshold Stimulus

minimum strength of stimulation required to cause a contraction

Latent Period

time between a stimulus and the beginning of a response in a muscle fiber

Summation

the combination of individual twitches where the muscle is unable to relax

Tetanus

a sustained contraction caused by high frequency stimulation that lacks any relaxation

Motor Unit

a motor neuron and the muscle fibers that it controls

Recruitment

increase in the number of motor units taking place in a muscle contraction

Muscle Tone

ongoing low-level contraction of some fibers in otherwise resting skeletal muscle

Isotonic Contraction

a contraction that creates force and moves a load by shortening the muscle

Isometric Contraction

a contraction that creates force without shortening

Origin

end of a muscle that attaches to a relatively immovable part

Insertion

end of a muscle attached to a moveable part

Prime Mover

muscle that provides most of the particular body movement; also called an agonist

Synergist

muscle that assists the action of an agonist

Antagonist

muscle that opposes a particular movement

Acetylcholine (ACh)

neurotransmitter that stimulates muscle fibers

Motor End Plate

specialized muscle fiber membrane that contains receptors for neurotransmitters

Plasma

The part of blood that consists a mixture of substances dissolved in water: nutrients, vitamins, hormones, electrolytes, and cellular wastes

Hemoglobin

Globular protein found on red blood cells that carries oxygen and carbon dioxide; causes blood to be red with oxygen

Hemopoiesis

Process of making red blood cells in the bone marrow

Erythropoietin

Hormone secreted by kidney and liver cells that promotes the rate of red blood cell formation; abbreviated EPO

Pericardium

The thin membranous sac that encloses the heart and proximal ends of the large blood vessels that are attached to the heart

Pericardial Cavity

The space surrounding the heart that contains serous fluid which reduces friction

Epicardium

The outermost layer of the heart known as the serous layer that reduces friction; consists of adipose tissue

Myocardium

The muscular layer of the heart that is richly supplied by blood, lymph, capillaries, and nerve fibers

Endocardium

The innermost layer of the heart consisting of elastic and collagenous fibers

Atria

The two upper chambers of the heart; receives blood from body and lungs; pumps into the ventricles

Ventricles

The two lower chambers of the heart; receives blood from the atria; pumps blood to the body and lungs

Septum

The muscular wall that separates the left and right chambers to ensure that oxygenated and deoxygenated blood don't mix (interventricular septum is between ventricles; interatrial septum is between atria)

Septal Defect

Congenital condition characterized by an opening in the septum

Tricuspid Valve

The heart valve that allows deoxygenated blood to flow from the right atrium to the right ventricle; consists of three cusps

Mitral Valve

The heart valve that allows oxygenated blood to flow from the left atrium to the left ventricle; consists of two cusps; also known as the bicuspid valve

Chordae Tendineae

Fibrous strings from the papillary muscles that attach to the cusps of the AV valves

Papillary Muscles

The cardiac muscles that extends inward from the ventricular walls of the heart and to which chordae tendineae attach

Pulmonary Valve

The heart valve leading from the right ventricle to the pulmonary trunk

Aortic Valve

The heart valve leading from the left ventricle to the aorta (and then rest of the body)

Stenosis

An abnormal narrowing of a body channel (like a blood vessel)

Coronary Arteries

First two arteries that branch off from the aorta; feeds oxygenated blood to the heart muscle

Myocardial Infarction

Heart attack; caused by a blocked artery that is feeding blood to the heart muscle

Systole

The phase of the heartbeat when the heart muscle contracts and pumps blood from the chambers into the arteries

Diastole

The phase of the heartbeat when the heart muscle relaxes and allows the chambers to fill with blood

Functional Syncytium

Mass of electrically joined cells that function as a unit; located in the atria and ventricles

Sinoatrial (SA) Node

The small mass of specialized cardiac muscle tissue in the right atrium that initiates cardiac cycles; reaches threshold by itself; also known as the "pacemaker" of the heart

Atrioventricular (AV) Node

Specialized mass of cardiac muscle fibers in the interatrial septum that transmits cardiac impulses from the SA node to the AV bundle

AV Bundle

Group of specialized muscle fibers that conducts impulses form the AV node to the ventricular muscle of the heart; also known as the Bundle of His

Purkinje Fibers

Specialized cardiac muscle fibers that conduct cardiac impulses form the AV bundle into the ventricular walls; stimulates the ventricular syncytium

Electrocardiogram (ECG)

A recording of the electrical activity associated with the cardiac cycle

Blood Vessels

Closed circuit of tubes that carry blood from the heart to cells and back again; includes arteries, arterioles, veins, venules, and capillaries

Arteries

Strong, elastic blood vessels adapted for transporting blood away from the heart under relatively high pressure

Arterioles

Small branch of an artery that communicates with a capillary network

Vasodilation

Increase in the diameter of a blood vessel that results in greater blood flow

Vasoconstriction

Decrease in the diameter of a blood vessel that results in a decrease in blood flow

Capillaries

The smallest blood vessel by diameter that connects an arteriole and a venule and allows diffusional exchange of nutrients and waste

Venules

Blood vessels that transports blood from capillaries to a vein

Veins

Blood vessels that transport blood toward the heart

Atherosclerosis

Disease of the arteries characterized by plaque build up that results in the narrowing of the artery

Arteriosclerosis

The thickening or hardening of the artery walls

Blood Pressure

The force blood exerts against the inner walls of arterial blood vessels

Systolic Pressure

The maximum pressure in arteries during ventricular contraction

Diastolic Pressure

The lowest pressure that remains in the arteries when the heart is relaxed (before the next contraction)

Stroke Volume

The volume of blood discharged from the left ventricle per contraction; about 70 mL for the average adult

Cardiac Output

Volume of blood per minute that the heart pumps

Blood Volume

The sum of formed elements and plasma volumes in the vascular system; about 5 L for the average adult

Peripheral Resistance

Friction between the blood and the walls of blood vessels that hinders blood flow

Blood Viscosity

The thickness of the blood; resistance to flow