Bio Exam 3

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.

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.

operculum

A protective flap that covers the gills of fishes

gill arches

a series of bony structures present in fish, which support the gills

gill filaments

long thin structures that extend from each gill arch

gill lamellae

stacked flat structures arranged at right angles to gill filaments, which increase the surface area of the fish gills and provide for countercurrent exchange

countercurrent exchange

the opposite flow of adjacent fluids that maximizes transfer rates; for example, blood in the gills flows in the opposite direction in which water passes over the gills, maximizing oxygen uptake and carbon dioxide loss.

lungs

a pair of spongy, air-filled organs located on either side of the chest cavity (thorax)

tidal ventilation

A breathing technique in most land vertebrates in which air is drawn into the lungs during inhalation and moved out during exhalation by the same path.

positive pressure breathing/ventilation

A breathing system used by amphibians in which air is pushed by muscular contraction into the lungs.

negative pressure breathing

A breathing system in which air is pulled into the lungs when the thoracic (chest) cavity volume is expanded.

Boyle's Law

pressure and volume of a gas are inversely related

trachea (vertebrates)

transmits air from pharynx to bronchi of lungs

bronchi

two short branches located at the lower end of the trachea that carry air into the lungs.

bronchioles

progressively smaller tubular branches of the airways

alveoli

tiny sacs of lung tissue specialized for the movement of gases between air and blood

flow through ventilation

the pattern of single-direction airflow over the gas exchange system during breathing in birds

electrolytes

minerals that carry electrical charges that help maintain the body's fluid balance

obligatory exchanges

exchanges (sometimes detrimental) that occur between an organism and its environment in order for it to conduct an essential function (such as breathing or waste elimination)

nitrogenous wastes

products of cellular metabolism that contain nitrogen, such as urea, uric acid, and ammonia

ammonia

A small, very toxic molecule (NH3) produced by nitrogen fixation or as a metabolic waste product of protein and nucleic acid metabolism.

urea

moderately toxic nitrogenous waste excreted in urine in mammals, amphibians, sharks and many bony fish

uric acid

relatively non-toxic, low solubility nitrogenous waste produced by birds, most reptiles and snails

protonephridia

networks of tubules with ciliated structures called flame bulbs in flatworms that pull fluid through branched ducts opening to the outside

metanephridia

excretory tubes in each segment of annelid worms

Malpighian tubules

tubules that excrete metabolic wastes into the intestine in arthropods

kidney

organ in vertebrates that removes urea, excess water, and other waste products from the blood and passes them to the ureter

ureter

A duct leading from the kidney to the urinary bladder.

urinary bladder

saclike organ in which urine is stored before being excreted

urethra

tube leading from the urinary bladder to the outside of the body

renal cortex

outer layer of the kidney

renal medulla

inner region of the kidney

renal pelvis

funnel-shaped reservoir that collects the urine and passes it to the ureter

nephron

tubular functional filtration unit of the kidney

proximal convoluted tubule (PCT)

first segment of the nephron between the glomerular capsule loop of Henle

Loop of Henle

the part of a kidney tubule between the proximal and distal convoluted tubules that is engaged in countercurrent multiplication to form a solute gradient in the kidney medulla

distal convoluted tubule (DCT)

segment of the nephron between the Loop of Henle and the collecting duct

peritubular capillaries

The network of tiny blood vessels that surrounds the proximal and distal tubules in the kidney

vasa recta

the capillary system in the kidney that serves the loop of Henle

collecting duct

the location in the kidney where processed filtrate, called urine, is collected from nephrons and concentrated before delivery into the renal pelvis

glomerulus

A ball of capillaries surrounded by Bowman's capsule in the nephron and serving as the site of filtration in the vertebrate kidney.

Bowman's capsule

cup-shaped strucutre of the nephron of a kidney which encloses the glomerulus and which filtration takes place.

podocytes

cells in the Bowman's capsule in the kidneys that wrap around capillaries of the glomerulus

filtration slits

Gaps between podocyte processes surrounding the glomerulus

fenestrations

pores through endothelial cells of glomerular capillaries that prevent movement of blood cells and large proteins into Bowman's capsule.

glomerular filtration

the hydrostatic pressure-driven passage of water and water-soluble small molecules from the plasma into Bowman's capsule

nephron reabsorption

Active or Passive, moving things out of nephron tubule back to blood

nephron secretion

the transfer of excess solutes/wastes from the blood vasculature directly through the walls of the nephron tubule into the nephron filtrate

parthenogenesis

Asexual reproduction in which females produce offspring from unfertilized eggs.