Nervous Tissue Flashcards
The nervous system
A) works with the endocrine system to maintain homeostasis.
B) communicates with the body via action potentials.
C) is responsible for thoughts and behaviors.
D) initiates voluntary movements.
*E) All of these are correct. *
Each of the following is part of the nervous system EXCEPT the:
A) brain
B) spinal cord
C) vertebral column
D) neurons
E) neuroglia
Which of the following correctly describes a function of the nervous system?
A) sensory: detect changes in the environment; relays information to the brain and spinal cord.
B) integrative: elicits an appropriate response such as muscle contraction or glandular secretion
C) motor: process and make decisions regarding sensory input; responsible for perception.
D) A and B are correct.
E) A, B and C are correct.
The central nervous system
A) excludes the cranial and spinal nerves, ganglia and sensory receptors.
B) is the source of thoughts and emotions.
C) is the destination of action potentials from motor neurons.
D) A and B are correct.
E) A, B and C are correct.
The peripheral nervous system
A) includes the brain and spinal cord.
B) may be divided into somatic, autonomic and enteric nervous systems.
C) is only involved with unconscious (involuntary) activities.
D) A and B are correct.
E) A, B and C are correct.
The somatic nervous system
A) provides motor signals and conscious control to skeletal muscles.
B) includes sympathetic and parasympathetic divisions.
C) regulates the gastrointestinal tract.
D) is dependent on the autonomic system for control.
E) includes motor neurons to smooth muscles.
Neurons
A) are electrically excitable cells.
B) vary greatly in size.
C) have a perikaryon enriched with the organelles for protein synthesis.
D) A and B are correct.
*E) A, B and C are correct. *
Which of the following is NOT true?
A) A dendrite is a nerve fiber that receives impulses from other neurons.
B) Most neurons have many axons and one dendrite.
C) An axon sends an impulse to another neuron or to an effector cell.
D) Slow axonal transport moves axoplasm in only one direction.
E) Fast axonal transport uses microtubules to move materials in two directions.
Which of the following is true of a synapse?
A) The presynaptic neuron carries a nerve impulse away from a synapse.
B) The postsynaptic neuron carries a nerve impulse toward a synapse.
C) A synapse is the site of where two neurons or a neuron and an effector meet.
D) The presynaptic neuron releases chemical messengers called hormones.
E) The synapse of a neuron and a gland is called a neuromuscular junction.
Most of the neurons in the brain and spinal cord are ___ neurons.
A) anaxonic
B) bipolar
C) Purkinje cells
D) multipolar
E) univocal
Neuroglia
A) comprise about one-half of the tissue in the CNS.
B) retain mitotic potential but do not conduct nerve impulses.
C) support and protect neurons.
D) A and B are correct.
**E) A, B and C are correct. **
Astrocytes:
A) support neurons in the peripheral nervous system.
B) form the blood-brain barrier.
C) regulate growth, migration and interconnection of neurons in the adult brain.
D) form myelin on central nervous system neurons.
E) maintain the blood-cerebrospinal fluid barrier.
Which neuroglia cells produce myelin?
A) oligodendrocytes
B) Schwann cells
C) satellite cells
D) A and B are correct.
E) A, B and C are correct.
Gray matter
A) consists of neuron cell bodies, neuroglia and unmyelinated nerve fibers.
B) is found at the periphery of the spinal cord.
C) may be found in clusters called ganglia in the central nervous system.
D) may be found in clusters called nuclei in the peripheral nervous system.
E) All of the above are correct.
Which of the following statements is correct?
A) Ion channels in neuron plasma membranes block electron flow across those membranes.
B) Action potentials allow cells to communicate over short distances only.
C) Graded potentials allow cells to communicate over either long or short distances.
D) The electrical current in living cells is the flow of electrons across a plasma membrane.
E) Neurons exhibit differences in electrical voltage across their plasma membranes.
When ions move across the plasma membrane,
A) they pass though specific phospholipids that serve as ion channels.
B) they flow up their concentration gradient toward an area of the same charge.
C) they create a flow of electrical current that can disturb the resting membrane potential.
D) A and B are correct.
E) A, B and C are correct.
Which of the following is NOT true of ion channels?
A) Leakage channels randomly open and close.
B) Leakage channels make the plasma membrane more permeable to Na+ than to K+.
C) There are more K+ leakage channels than Na+ leakage channels.
D) Voltage-gated channels are involved in the generation and conduction of action potentials.
E) Ligand-gated channels are controlled by neurotransmitters, hormones, or specific ions.
Which of the following contributes to the maintenance of a resting membrane potential?
A) equal distribution of ions across the plasma membrane
B) ATPase movement of 2 Na+ into the cell for 3 K+ pushed out of the cell
C) presence of negatively charged proteins and phosphates just outside the plasma membrane
D) lower plasma membrane permeability to Na+ than K+
E) All of the above are correct.
Graded potentials
A) arise when ion movement causes a minor change in the resting membrane potential.
B) usually propagate down the length of an axon.
C) occur when voltage-gated channels open.
D) are most often observed in axons.
E) are usually associated with ion movement through leakage channels.
Action potentials
A) arise slowly and are observed primarily in dendrites and cell bodies.
B) arise when a stimulus is strong enough to open mechanically-gated ion channels.
C) occur in three phases: latent, graded and polarizing.
D) vary in size depending on the strength of the initial stimulus.
**E) allow an impulse to travel over long or short distances. **
Place the events involved in generating an action potential in the order in which they occur”
- K+ moves out of the cell.
- Na+ activation gates open.
- Excess K+ leaves cell causing hyperpolarization.
- Na+ enters cell and voltage becomes less negative.
- K+ channels close.
- threshold stimulus arrives.
- Leakage channels restore resting membrane potential.
- Na+ inactivation gates close and K+ open.
A) 6, 4, 2, 8, 1, 3, 5, 7
B) 6, 4, 8, 2, 1, 3, 5, 7
C) 6, 2, 4, 8, 1, 3, 5, 7
D) 6, 2, 4, 8, 3, 1, 5, 7
E) 6, 2, 4, 3, 8, 1, 5, 7