The Nervous System

both the electrical and chemical gradients

During depolarization, which gradient(s) move(s) Na+ into the cell?

the depolarization phase

During the action potential, the rapid decrease in sodium permeability and simultaneous increase in potassium permeability is responsible for _.

Na+ is pumped out of the cell and K+ is pumped into the cell.

The Na+-K+ pump actively transports both sodium and potassium ions across the membrane to compensate for their constant leakage. In which direction is each ion pumped?

mixed nerves

spinal nerves are _ nerves

hydrocephalus

the blockage of cerebrospinal fluid outflow in the brain can cause accumulation of fluid, resulting in cranial enlargement in infants. This condition is called__.

Na+; Cl-

the membrane of neurons at rust are permeable to _ but only slightly permeable to _.

loss of sensation and flaccid paralysis of the area served by the nerve

what could result if a spinal nerve is severely damaged?

sodium

what ion depolarizes the membrane when it diffuses into the axon of a neuron?

Sodium gates open and the membrane depolarizes

what is the first event of an action potential?

-70mV

what is the value for the resting membrane potential for most neurons?

dendrite

what part of a neuron receives signals and sends a message to the cell body?

primary motor area

what part of the brain do we use when initiating skeletal muscle movement?

alcohol

which of the following can adversely affect brain development in the fetus?

ataxia

which of the following conditions would result from damage to the cerebellum?

blood vessels constrict

which of these is a sympathetic effect?

increases peristalsis within the stomach and small intestines

which of these is an affect of the parasympathetic nervous system?

thalamus; diencephalon

which of these parts of the brain is correct matched with its region?

ventral root

In flaccid paralysis, muscles atrophy because they are not receiving neural stimulation. Damage to which specific part of the spinal cord would cause flaccid paralysis?

Na+ and Cl-

The concentrations of which two ions are highest outside the cell.

depolarize

The membrane potential is becoming more positive than the resting membrane potential.

repolarize

The membrane potential is moving from a more positive value toward resting membrane potential.

astrocytes

What cells of the nervous system are responsible for anchoring neurons to their blood vessels and controlling the extracellular fluid concentrations of potassium and neurotransmitters?

vagus nerves

What cranial nerve pair supplies many organs in the ventral body cavity?

choroid plexus

What produces cerebrospinal fluid?

during the peak of depolarization

during the action potential, when does sodium permeability initially DECREASE?

hyperpolarize

membrane potential becomes more negative