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Name: ___________________________________________________________
Assignment #3 – BIOL 2404 Lecture
Answer the following questions.
- What are the 3 general functions of the muscular system? What is the primary function?
a. ___________________________________________________
b. ___________________________________________________
c. ___________________________________________________
- What are the three types of muscle tissues?
- The smallest functional unit of a muscle fiber is called a(n) ______________________________________.
- The thin myofilaments are called _________________________________________.
- How are the two proteins, troponin and tropomyosin, capable of preventing muscle contraction?
- What mineral is needed to expose the active site on actin?
- The thick myofilaments are called ________________________________________.
- The ability of the muscle to respond to stimuli from a nervous impulse is called
______________________________________.
- All the muscle fibers controlled by a single motor neuron constitute a
______________________________________.
- Which myofilament contains the crossbridge or head?
- What two bands of the sarcomere are seen as the striations in skeletal muscle?
- The neurotransmitter secreted at the neuromuscular junction is _________________________________.
- The calcium needed for muscle contraction is stored in what part of the muscle fiber?
- What is a prime mover muscle?
- Put the following muscle contraction and relaxation steps in order:
______ acetylcholine travels across the synaptic gap
______ actin and myosin form linkages
______ Ca
2+
ions diffuse into fiber; bind to troponin
______ actin and myosin linkages are broken
______ calcium ions diffuse out of the skeletal muscle
______ ACH released from distal end of motor neuron
______ cholinesterase decomposes acetylcholine
______ acetylcholine stimulates the skeletal fiber
______ muscle relaxes
______ muscle fiber shortens (contracts)
- When the muscle is stimulated, until the relaxation phase is eliminated, the muscle is said to be in a
state of complete __________________________________________.
- The aerobic method of generating ATP from glucose is called ________________________________.
- What is the by-product of the anaerobic breakdown of glucose?
- Muscle accounts for approximately ______________% of body weight.
- The state of constant muscle contraction by a few muscle fibers always is known as
_____________________________________________.
- The outermost covering of a muscle is called the __________________________________________,
while the connective tissue covering of the fascicles is called the ______________________________.
The connective tissue that surrounds each muscle fiber is known as the
________________________________________________.
- The movement of a limb away from the body would be called ________________________________.
- Bringing a limb closer to the body is called ________________________________________________.
- Which of these sarcomere bands or lines narrows when a skeletal muscle contracts?
a) _____ H band b) _____ A band c) _____ I band d) _____ M line
Complete the following.
Correctly relate the order of contraction events in a muscle fiber by numbering each event below. Place
the number in front of the event.
- Myosin heads bind to active sites on actin molecules
- Myosin heads return to their high-energy shape (cocked), ready for next working stroke
- Calcium ions bind to troponin
- Myosin cross bridges detach from actin
- ACh is released into the neuromuscular junction
- Troponin changes shape exposing the active site
- The sarcolemma depolarizes
- Myosin heads pull on the thin filaments and slide them toward the sarcomere
- The sarcoplasmic reticulum releases calcium ions
In the space provided, write the letter of the description that best matches the term or phrase.
_____ 1. Neuron a. the difference in electrical charge across a cell membrane
_____ 2. Dendrite b. part of a neuron that conducts nerve impulses
_____ 3. Axon c. the membrane potential of a neuron at rest
_____ 4. nerve d. nerve cell; transmits information throughout the body
_____ 5. membrane potential e. bundle of neurons
_____ 6. resting potential f. part of a neuron that receives information from other neurons
_____ 7. action potential g. a junction at which a neuron meets another cell
_____ 8. Synapse h. a signal molecule that transmits nerve impulses across synapses
_____ 9. neurotransmitter i. nerve impulse
Answer the following questions.
Write the correct term from the list below in the space next to its definition .
Brain Hypothalamus reflex
brain stem Interneurons sensory neuron
central nervous system motor neuron spinal cord
Cerebellum peripheral nervous system thalamus
Cerebrum
In the space provided, write the letter of the description that best matches the term or phrase.
__________________ 10. carries motor responses from the central nervous system to muscles, glands,
and other organs
__________________ 11. site of capacity for learning, memory, perception, and intellectual function
__________________ 12. consists of the brain and spinal cord
__________________ 13. relays sensory information
__________________ 14. dense cable of nervous tissue that runs through the vertebral column
__________________ 15. contains neurons that branch throughout the body
__________________ 16. carries information from sense organs to the central nervous system
__________________ 17. the body’s main processing center
__________________ 18. regulates breathing, heart rate and endocrine functions
__________________ 19. link neurons to each other
__________________ 20. collection of structures leading down to the spinal cord
__________________ 21. regulates balance, posture, and movement
__________________ 22. a sudden, rapid, and involuntary self-protective motor response
_____ 23. sensory receptor a. the lining of photoreceptors and neurons in the eye
_____ 24. Retina b. aids in hearing
_____ 25. Rod c. type of photoreceptor that responds best to dim light
_____ 26. Cone d. runs from the back of each eye to the brain
_____ 27. optic nerve e. helps maintain equilibrium
_____ 28. Cochlea f. a specialized neuron that detects sensory stimuli
_____ 29. semicircular canal g. type of photoreceptor that enables color vision
Label the correct parts of the brain and spinal cord on the diagram at the left below.
a. cerebellum d. hypothalamus g. spinal cord
b. medulla oblongata e. corpus callosum h. cerebrum
c. thalamus f. pons i. pituitary gland
General Senses
Label the following mechanoreceptors.
