Mastering A And P

Question 1

The all or none principle is accurately described as?

Answer 1

All stimuli that bring the membrane to threshold generate identical action potential

Question 2

How is an action potential propagated along the axon?
A. An efflux of potassium from the current action potential depolarizes the adjacent are
B. An influx of sodium ions from the current action potential depolarizes the adjacent area.
C. Stimuli from the graded (local) potentials from the soma and dendrites depolarize the entire axon

Answer 2

B.

Question 3

The velocity of the action potential is fastest in which of the following axons?
A. A large unmyelinated axon
B. A small myelinated axon
C. A small unmyelinated

Answer 3

B. The myelination acts as an insulation and the action potential is generated only at the nodes of ranvier. Propagation along myelinated axons is known as saltatory conduction.

Question 4

Where are action potentials regenerated as they propagate along myelinated axon?

Answer 4

At the NODES

Question 5

The node to node jumping regeneration of an action potential along myelinated axon is called

Answer 5

Saltatory propagation

Question 6

An action potential is self regenerating because

Answer 6

Depolarizing currents established by the influx of Na+ flow down the axon and trigger an action potential at the next segment

Question 7

Why does regeneration of the action potential occur in one direction, rather than in two directions?

Answer 7

The inactivation gates of voltage gated Na+ channels close in the node, or segment, that has just fired an action potential.

Question 8

A molecule that carries information across a synaptic cleft is a

Answer 8

NEUROTRANSMITTER molecules carry information across a synaptic cleft

Question 9

When calcium ions enter the synaptic terminal

Answer 9

They cause vesicles containing neurotransmitter molecules to fuse to plasma membrane of the sending neuron

Question 10

When neurotransmitter molecules bind to receptors in the plasma membrane of the receiving nueron,

Answer 10

Ion channels in the plasma membrane of the receiving neuron open

Question 11

What causes calcium channels in the synaptic knob open?

Answer 11

Depolarisation of the presynaptic membrane due to an arriving action potential.

Question 12

The acetylcholine receptor is an example if what type of channel?

Answer 12

A chemically gated channel

Question 13

Order of the event synaptic activity

Answer 13

An action potential arrives and depolarises the synaptic knob. Extracellular calcium enters the synaptic knob, triggering exocytosis of ACh. ACh binds to receptors and depolarises postsynaptic membrane. ACh is removed by AChE.

Question 14

The most numerous white blood cells in peripheral circulation are the 
A. Lymphocytes
B. Basophils
C. Neutrophils
D. Monocytes
E. Eosinophils

Answer 14

NEUTROPHILS

Question 15

\_\_\_\_\_\_\_\_\_\_\_\_\_\_ are large phagocytic white blood cells that spend most of their time outside the blood fixed and free phagocytic cells.
A. Monocytes
B. Lymphocytes
C. Basophils
D. Neutrophils
E. Eosinophils

Answer 15

MONOCYTES

Question 16

White blood cells that are increased in allergic individuals are the 
A. Neutrophils
B. Eosinophils
C. Lymphocytes
D. Basophils

Answer 16

EOSINOPHILS

Question 17

Which of these descriptions best matches the term lymphocytes?
A. Kill bacteria using cytotoxic chemicals
B. Become macrophages
C. Defend against specific pathogens or toxins
D. Often elevated in allergic individuals
E. Release histamine

Answer 17

C.

Question 18

During a bacterial infection you would expect to see increased numbers of 
A. Eosinophils
B. Basophils
C. Neutrophils
D. Reticulocytes

Answer 18

NEUTROPHILS

Question 19

Which is the correct statement regarding action potentials?
A. Action potential depend on leak channels
B. Action potentials are localised changes in the transmembrane potential
C. Action potentials depend on voltage-fated channels
D. An action potential begins with the opening of the voltage-gated potassium ion channels

Answer 19

C. Action potentials depend on voltage gated channels