Bio Quiz 5

muscle fiber

long slender skeletal muscle cells

myofibril

the elongated contractile protein filaments found in skeletal and cardiac muscle cells.

striations

alternate dark and light bands observed in skeletal and cardiac muscle cells, attributable to the presence and alignment of repeating sarcomere units along myofibrils

muscle fascicle

a bundle of muscle fibers

sarcolemma

muscle cell membrane

transverse tubule

Membranous channel that extends inward from a muscle fiber membrane

sarcoplasm

cytoplasm of a muscle cell

sarcoplasmic reticulum

specialized endoplasmic reticulum of muscle cells, stores calcium

terminal cisternae

enlarged areas of the sarcoplasmic reticulum surrounding the transverse tubules.

sarcomere

contractile unit of a myofibril

Z-disc

provides anchorage for thin filaments of a sarcomere, forms the boundary between adjacent sarcomeres

M-line

middle of sarcomere, where myosin thick filaments are anchored/centered

A-band

area that spans the full length thick (myosin) filaments and includes overlapping thin actin filaments

I-band of sarcomere

region of repeating sarcomeres of a myofibril that contains only thin actin (actin)filaments

H-zone of sarcomere

Middle region of sarcomere that contains only thick filaments

sarcomere thin filament

thin strands of actin and its troponin-tropomyosin complex projecting from the Z-discs toward the center of the sarcomere

thick filament

In skeletal and cardiac muscle tissue, a filament composed of bundles of myosin molecules.

tropomyosin

covers over myosin binding sites on sarcomere thin filaments in a regulated fashion

troponin

A calcium-binding protein of muscle that regulates tropomyosin's interation with thin filaments

open circulatory system

system in which blood is not always contained within a network of blood vessels; hemolymph bathes the tissues and organs directly and there is no distinction between the circulating fluid and the interstitial fluid.

closed circulatory system

A circulatory system in which blood is confined to vessels and is kept separate from the interstitial fluid.

single circulatory system

Blood passes through the heart once only in a complete circuit of the body e.g. in a fish

Double circulatory system

the circulation circuit of blood from the heart to the lungs is separate from the circulation of blood from the heart to the rest of the body

neurogenic heart

A heart that will not beat unless it receives regular electrical impulses from the nervous system

myogenic heart

A type of heart, such as in vertebrate animals, in which heart beats are initiated by specialized muscle cells located within the heart itself.

intercalated discs

specialized connections between cardiac muscle cells containing gap junctions, allowing electrical conduction

sinoatrial node

pacemaker of the heart

atrioventricular valve

either of two one-way heart valves through which blood flows from the atria to the ventricles

atrioventricular node

A specialized mass of conducting cells located in the area between the right atrium and ventricle of the heart.; delays conduction from atria to ventricle region

atrial systole

contraction of the atria

atrial diastole

relaxation of the atria

ventricular systole

contraction of ventricles

ventricular diastole

relaxation of the ventricles

semilunar valve

a valve located at each exit of the heart, where the aorta leaves the left ventricle and the pulmonary artery leaves the right ventricle

aortic valve

The semilunar valve separating the aorta from the left ventricle that prevents blood from flowing back into the left ventricle.

pulmonary valve

valve positioned between the right ventricle and the pulmonary artery that prevents blood from flowing back into the right ventricle

plasma

Fluid portion of blood

erythrocyte

red blood cell, contains hemoglobin for oxygen transport

leukocyte

white blood cell, plays a role in immune function

platelet

thrombocyte- a cell fragment that helps blood clot

artery

A thick walled blood vessel that carries blood away from the heart

arteriole

branches of arteries that have endothelia lined with thin layer of smooth muscle

capillary

A tiny blood vessel where substances are exchanged between the blood and the body cells.

venule

small vein with endothelium and thin connective tissue sheath

vein

A large blood vessel that carries blood back to the heart.

pulmonary respiration

the exchange of oxygen and carbon dioxide between the lung gas exchange circuit and capillaries

internal respiration

exchange of gases between the blood and the tissues of the body (other than the lungs)

external gills

Highly branched and folded outer extensions of the body surface that provide a large surface area for gas exchange with water

internal gills

Structures enclosed in protective body cavities that provide a large surface area for gas exchange with water; typical of mollusks, arthropods, and fishes.

tracheae (insects)

tubes leading from the spiracle openings to the tracheoles that are part of the gaseous exchange system.