Anatomy and Physiology Chapter 11

Match the word with its corresponding statement: The all-or-none phenomenon.

An action potential occurring only if enough Na+ enters the cell and threshold is achieved

Which of the following neuroglia is most responsible for helping determine capillary permeability in nervous tissue?

Astrocyte

Based on your understanding of this cell's function, these cells influence neuronal function by "mopping up" leak potassium and by recapturing and recycling released neurotransmitters. These cells also participate in information processing in the brain.

Astrocyte, which is depicted by (a)

Which of the following types of glial cells are the most abundant and versatile and aid in making exchanges between capillaries and neurons?

Astrocytes

The point marked 2, on the figure, can be described as __________.

a voltage change brought on by the accumulation of graded potentials arriving at the axon hillock

Multiple sclerosis is __________.

an autoimmune disease that leads to destruction of the myelin sheaths in the CNS

Match the term to its correct description: Endorphins __________.

are peptides with inhibitory, opiate-like actions

An appropriate label for B in the figure shown here could also be the __________.

central nervous system

Match the system with its correct description: The central nervous system __________.

consists from the brain and spinal cord to skeletal muscles

Match the system with its correct description: The peripheral nervous system __________.

consists of cranial and spinal nerves carrying impulses to and from the brain and spinal cord

Match the term to its correct description: Acetylcholine __________.

excites skeletal muscle

A potential of -90 mV is considered __________.

hyperpolarized

Dopamine __________.

is a "feel good" transmitter; deficient in Parkinson's disease

Match the term to its correct description: Norepinephrine __________.

is a neurotransmitter of postganglionic neurons in the sympathetic nervous system

Spatial summation occurs when __________.

multiple local potentials occur at different places on the same cell at the same time

Indicate, by letter, where one would find short-distance signals called graded potentials.

A. dendrite

The point marked 1, on the figure, can be described as __________.

All gated Na+ and K+ channels are closed.

You are driving and see a red light ahead. Your nervous system indicates "stop", and your foot hits the brake. Which portion of the nervous system, as indicated in the figure, is responsible for the decision to stop?

B. Integration. The nervous system processes and interprets sensory input and decides what should be done at each moment—a process called integration.

In the figure above, which letter(s) correspond to the peripheral nervous system?

Both A and C represent portions of the peripheral nervous system (PNS).

The axon hillock of the neuron makes a "decision" to fire an action potential based on the timing and number of pros (in the form of EPSPs) and cons (IPSPs) that weigh into the decision. Given this, which of the following is true?

Changes in the concentration of sodium, potassium, or chloride may affect a neuron's ability to make the "decisions" required in conscious thought.

If A, in the figure shown, represents a neuron communicating between the eye and the portion of the brain responsible for interpreting vision, then neuron A is in what type of nerve?

Cranial nerve

Match the ionic activity associated with the following phase of an action potential: opening and then closing of the Na+ channels.

Depolarization phase in the generation of an action potential

Which of the following circuit types is exemplified by impulses that travel from a single neuron of the brain, activate one hundred or more motor neurons in the spinal cord, and excite thousands of skeletal muscle fibers?

Diverging circuit

Which of the following neurotransmitters acts as a natural opiate?

Endorphins

Which of the following types of glial cells line the central cavities of the brain and spinal cord, where they help to circulate the cerebrospinal fluid?

Ependymal cells

Which statement is true of the glial cell pictured above?

Glial cell processes touch nearby neurons, monitoring their health, and when they sense that certain neurons are injured or in other trouble, the microglial cells migrate toward them.

Which of the following events is not involved in the transfer of information across a chemical synapse?

Ions flow directly from one neuron to the next

Based on your understanding of this cell's function, you might expect this cell to be active in neurodegenerative disorders like Alzheimers where this cell removes damaged neurons. Additionally, this cell is active in preventing encephalitis and meningitis due to its ability to phagocytize microorganisms.

Microglia, which is depicted by (b)

Which disease is directly related to demyelination?

Multiple sclerosis

Based on your understanding of this cell's function, diseases that affect the myelin sheath of neurons, like multiple sclerosis, likely affects which of the cells in the figure?

Oligodendroctye, which is depicted by (d)

During which phase of an action potential are voltage-gated K+ channels open, while voltage-gated Na+ channels are closed?

Repolarizing phase

Which of the following characteristics is not associated with a myelinated nerve fiber?

Slow conduction of nerve impulses

Match the term to its correct description: Numerous nerve impulses arriving at a synapse at closely timed intervals exert a cumulative effect.

Temporal summation

Match the ionic activity associated with the following phase of an action potential: from the opening of the Na+ channels until the Na+ channels begin to reset to their original resting state.

The absolute refractory period

Which of the following divisions of the nervous system is also known as the involuntary nervous system?

The autonomic nervous system

Match the ionic activity associated with the following phase of an action potential: excessive potassium efflux as a result of relatively slower closure of the potassium gates.

The phase in an action potential known as the "after hyperpolarization"

Which of the following statements concerning inhibitory synapses (IPSPs) is correct?

The postsynaptic membrane becomes more permeable to potassium and chloride

Match the ionic activity associated with the following phase of an action potential: opening of potassium gates and the rushing out of K+.

The repolarization phase in an action potential

Match the ionic activity associated with the following phase of an action potential: All voltage-gated Na+ and K+ channels are closed.

The resting state of a neuron

In the figure above, D most specifically represents which subdivision of the nervous system?

The somatic nervous system

What is the primary difference between the somatic nervous system and the autonomic nervous system?

The somatic nervous system allows us to consciously control our skeletal muscles, and the autonomic nervous system controls activity that humans cannot consciously control, such as the pumping of the heart and the movement of food through the digestive tract.

Which of the following is not true of chemical synapses?

They transmit nerve impulses directly from one neuron to another

Match the term to its correct description: Any stimulus above this intensity will result in an action potential in a neuron.

Threshold stimulus

Saltatory conduction refers to _______.

a conduction process in myelinated axons where the electrical signal appears to jump from gap to gap along the axon

Which of the following defines integration?

processing and interpretation of sensory input and determining what should be done at each moment in the body

Reflexes are __________.

rapid automatic responses to a stimulus in which the particular stimulus always produces the same motor response

The point marked 3, on the figure, can be described as __________.

representing the portion of the action potential, where Na+ entry depolarizes the neuron, opening up additional voltage-dependent Na+ channels that allow in even more Na+

Calcium has a great many roles in the body from providing structure to bones, stimulating muscle contraction, altering heart rate, influencing heart strength and stimulating hormone release. In a neuron, calcium's main role is __________.

stimulating the release of neurotransmitters

Match the term to its correct description: A stimulus that fails to generate an action potential is a __________.

subthreshold stimulus

Bodily functions that follow "a law unto itself" are controlled by the involuntary nervous system. This system is also termed __________ and functions to __________.

the autonomic nervous system (ANS); conduct impulses from the CNS to cardiac muscle, smooth muscle, and glands

The point marked 5, on the figure, can be described as __________.

the period of increased K+ permeability that typically lasts longer to restore the resting state

The point marked 4, on the figure, can be described as __________.

the point in time when Na+ entry declines and the slow voltage-gated K+ channels open

The voluntary nervous system is to the involuntary nervous system as __________.

the somatic nervous system is to the autonomic nervous system