To make a muscle contract more strongly, the nervous system can activate more motor neuron units. This is called
A. recruitment
B. summation
C. incomplete tetanus
D. twitch
E. treppe
recruitment
The functional unit of a muscle fiber is the _________, a segment from one Z disc to the next.
A. myofibril
B. I band
C. sarcomere
D. neuromuscular junction
E. striation
sarcomere
Before a muscle fiber can contract ATP must bind to
A. a Z disc
B. the myosin head
C. tropomyosin
D. troponin
E. actin
the myosin head
Before a muscle fiber can contract, Ca must bind to
A.calsequestrin
B. the myosin head
C. tropomyosin
D. tropnin
E. actin
tropnin
Skeletal muscle fibers have_________, whereas smooth muscle cells do not.
A. T tubules
B. ACh receptors
C. thick myofilaments
D. thin myofilaments
E. dense bodies
T tubules
Smooth muscle cells have________, whereas skeletal muscle fibers do not.
A. sarcoplasmic reticulum
B. tropomyosin
C. calmodulin
D. Z discs
E. myosin ATPase
calmodulin
Single-unit smooth muscle cells can stimulate each other because they have
A. a latch-bridge
B. diffuse junctions
C. gap junctions
D. tight junctions
E. cross-bridges
gap junctions
Slow oxidative fibers have all of the following except
A. an abundance of myglobin
B. an abundance of glycogen
C. high fatigue resistance
D. a red color
E. a high capacity to synthesize ATP aerobically
an abundance of glycogen
The minimum stimulus intensity that will make a muscle contract is called_________
threshold
A state of prolonged maximum contraction is called____
complete tetanus
The neurotransmitter that stimulates skeletal muscle is__________
acetylcholine
Muscle contains an oxygen-binding pigment called__________
myoglobin
The_________ of skeletal muscle play the same role as dense bodies in smooth muscles.
Z discs
A state of continual partial muscle contraction is called___
muscle tone
________ is an end product of anaerobic fermentation that cause muscl fatigue
lactic acid
True or False
Each motor neuron supplies just one muscle fiber
False
Slow oxidative fibers are relatively resistant to fatigue
true
Cardiac and some smooth muscle are autorhythmic, but skeletal muscle is not.
true
The basal cavity is divided by the nasal septum into right & left_____
A. nares
B. vestibules
C. fossae
D. choanae
E. conchae
fossae
The largest air passages that engage in gas exchange with the blood are
A. the respiratory bronchioles
B. the terminal bronchioles
C. the primary bronchi
D. the alveolar ducts
E. the alveolar
the respiratory bronchioles
Respiratory arrest would most likely result from a tumor of the
A. pons
B. midbrain
C. thalamus
D. cerebellum
E. medulla oblongata
medulla oblongata
Which of these values would normally be the highest?
A. tidal volume
B. inspiratory reserve volume
C. expiratory reserve volume
D. residual volume
E. vital capacity
vital capacity
Poor blood circulation causes_______ hypoxia
A. ischemic
B. histotoxic
C. hemolytic
D. anemic
E. hypoxemic
ischemic
The duration of an inspiration is set by___________
A. the pneumotaxic center
B. the phrenic nerves
C. the vagus nerves
D. the I neurons
E. the E neurons
the pneumotaxic center
Within each lung, the airway forms a branching complex called the_____________
bronchinal tree
____________disorders reduce the speed of airflow through the airway.
obstructive
A blood pH > 7.45 is called_______ and can be caused by CO2 deficiency called__________
alkalosis/ hypercapnia
True or False
Pneumothorax is the only cause of atelectasis
False
True or False
Most of the air one inhales never makes it to to the alveoli
False