A sacromere is best described as
a unit within a myofibril
Myofibrils are composed primarily of
actin and myosin
Neurotransmitters are stored in vesicles within
motor neuron endings
Creatine phosphate serves to
supply energy for the synthesis of ATP
ADP molecules on the surface of actin serve as active sites for the formation of cross bridges with molecules of
myosin
the amount of oxygen needed to support the conversion of lactic acid to glucose is called the
oxygen debt
A muscle cramp is likely due to the lack of
ATP
An example of a partial but sustained contraction wold be
muscle tone
A motor unit includes
several muscle fibers and one motor neuron
The increase in the number of motor units activated when the intensity of stimulation increases is called
recruitment
The all-or-none response means
when a muscle fiber contracts, it contracts completely
In a recording of a muscle twitch, the delay between the time a stimulus is applied and the time the muscle responds is called the
latent period
Endomysium separates individual muscle fibers
true
A motor neuron and the muscle fibers that it controls constitute a motor unit
true
The cytoplasmic extensions that provide the main receptive surfaces for neurons are
dendrites
The rhythmic, wavelike motion produced by smooth muscles in tubular visceral organs is called peristalsis
true
Masses of myelinated nerve fibers appear
white
Which of the following is NOT a type of neuroglial cell?
Nissl cell
When a nerve fiber is polarized, the concentration of
sodium ions is higher on the outside of its membrane and potassium ions is higher on the inside
Which of the following lists the parts of a reflex arc in the correct sequence?
Receptor, sensory neuron, interneuron, motor neuron, effector
The part of the brain that functions to coordinate voluntary muscle movements is the
cerebellum
Which of the following is closely associated with the diencephalon?
thalamus
The complex network of tiny islands of gray matter within the brain that activates the cerebral cortex to a state of wakefulness is the
reticular formation
When a neuron becomes more excitable as a result of incoming subthreshold stimulation, it is said to be
facilitated
In the central nervous system, myelin is formed by
oligondendrocytes
Within the meninges, cerbrosipinal fluid occupies the
suborachoid space
During an action potential, repolarization occurs as a result of
potassium ions diffusing to the outside of the cell membrane
Astrocytes are thought to provide structural support within the nervous system
true
Interneurons are specialized to carry impulses from receptor cells into the brain or spinal cord
false
Nodes of Ranvier occur between adjacent neurons
true
A nerve is a single neuron that transmits nerve impulses
false
A deficiency of calcium in the body can result in continuous muscle contractions, or tetany
true
The subarachnoid space within the meninges contains cerebrospinal fluid
true
The gray comissure of the spinal cord surrounds the central canal
true
Sympathetic tone is defined as continuous stimulation of smooth muscles in the walls of blood vessels, which results in partial constriction
true
Brain damage to the temporal lobe, where recent memory is processed, can result in the inability to form long-term memory
true
The peripheral nervous system is composed of
somatic and autonomic
The autonomic system is composed of
sympathetic and parasympathetic
Which of the following is the main function of the autonomic nervous system
maintains homeostasis without conscious effort
There are _ pairs of cranial nerves and _ pairs of spinal nerves.
12;31
What is the function of the somatic nervous system?
contraction of skeletal muscles; voluntary movements
What is the function of the autonomic nervous system?
contraction of smooth muscle
The biconcave cells in blood that lack nuclei when they are mature are the
red blood cells
Which of the following is an agranulocyte
monocyte
The normal white blood cell count is between
5,000 - 10,000 cells per cubic millimeter
A primary function of lymphocytes is to
act against foreign substances
Platelets are best defined as
cytoplasmic fragments of cells
As a platelet plug forms,, platelets release the vasocontricting substance called
serotonin
The basic event is the formation of a blood clot is the change of
fibrinogen to fibrin
Type AB blood contains
A and B antigens but no antibodies
Which of the following elements is included in hemoglobin molecules?
iron
Which of the following usually accounts for the smallest percentage of leukocytes in a blood sample?
basophils
The most active phagocytic cells among the leukocytes(white blood cells) are
neutrophil and monocytes
The most important action of plasma albumins is
help maintain osmotic pressure
Which of the following serves as an enzyme in the blood coagulation mechanism?
thormbin
Patients with leukemia have a tendency to bleed because they have a deficiency of
platelets
Erythorblastosis fetalis can be prevented by treating
Rh- negative mothers with anti-Rh agglution
Two substances that are useful for dissolving blood clots are
urokinase and streptokinase
Persons with type AB blood are sometimes called universal donors
false
A red blood cell contains a large nucleus; it is thicker near the center and thin around the rim of the cell
false
Platelet plug is formed when fibrinogen is converted to fibrin
false
Tissue that forms a loose-fitting sac around the heart is the
pericardium
Which of the following represents correct sequence of parts through which blood moves in passing from the vena cave to lungs?
right atruim,tripcuspid valve, right ventricle, plumonary semi lunar valve
Skeleton of the hear consists of
Both fibrious connective tissue in interventricular septum and circling heart valves
When the ventricular walls contracts, the
bicuspid and tricuspid valves close
Which is not branch of aorta
pulmonary artery
Correct sequence of parts that function to carry cardiac impulses is
A-node, A-V node, A-bundle, Purkinje fibers
Which type of blood vessel serves as a blood reservoir?
veins
Blood pressure in the systemic arteries is greatest during
ventricular systole
Plasma proteins that remain in the blood capillaries help to
maintain osmotic pressure of blood
Destiny of capillaries within a tissue varies directly with the tissue's
rate of metabolism
In an ECG pattern, the P wave is caused by
depolarization of atrial muscle fibers
In an ECG pattern, the T wave is caused by
polarization of ventricular muscle fibers
In an ECG pattern, P-Q interval indicates how long it takes for the cardiac impulses to travel from the
S-A node to ventricular muscle fibers
Which of the following might serve as a secondary pacemaker for the heart?
A-V node and Purkinje fibers
Molecules within the blood are forced out through the walls of capillaries as a result of osmotic pressure
false
SA node relays nerve impulses into the AV bundle of the interventricular septum and AV node is responsible for the rhythmic contractions of the heart.
false