Chapter 11 flashcards

A & P 1

What are the three major functions of the nervous system?

Sensory input, integration brain, and motor output

What does the sensory input do for the nervous system?

detach stimulus

What does the motor output do for the nervous system?

Carries instructions from the brain to the muscles

What best represents the integration function of the nervous system?

Deciding to slow down and pull your car over

What is the overall function of the central nervous system (CNS)

Integrating and controlling center of the nervous system

What is the overall function of the peripheral nervous system (PNS)

Communication lines that link all parts

What makes up the CNS

Brain and spinal cord

What makes up the PNS

Cranial nerves, spinal nerves, and ganglia

The PNS has two different divisions, what are they?

Afferent- sensory, Efferent- motor

The motor (efferent) has two different parts, what are they?

Somatic and Autonomic

Somatic nervous system

Voluntary control and skeletal muscles

Autonomic nervous system

Involuntary control and visceral (organ)

True or False- The somatic nervous system conducts impulses from the CNS to cardiac muscle, smooth muscle, and glands

FALSE - autonomic

True or False- The sensory (afferent) division of the PNS conducts impulses from receptors to the CNS

True

True or False- The sympathetic division of the ANS mobilizes body systems during activity

True

True or False- Visceral motor nerve fibers conduct impulses from the CNS to the skeletal muscles

FALSE- Somatic

True or False- The autonomic nervous system is also called the voluntary system

FALSE- somatic

Ependymal cells

Line cerebrospinal fluid-filled CNS cavaties

Schwann cells

Form myelin sheaths around PNS nerve fibers

Oligodendrocytes

Form myelin sheaths around CNS nerve fibers

Astrocytes

Assist in exchanges between blood capillaries and CNS neurons

Microglial cells

Defensive cells in the CNS

Satellite cells

Surround and support neuron cell bodies in the PNS

What describes neurons?

Structural units of the nervous system and specialized to generate and transmit electrical signals

In addition to being excitable cells, list three other special characteristics of neurons

Ingenuity, amitotic, and high metabolic rate

Also called the soma

cell body

Most responsible for receiving info from other neurons

dendrites

The major biosynthetic center of the neuron

Cell body

Generates nerve impulses and transmits them

axon

contains neurofibrils and a spherical nucleus

cell body

The conducting region of the neuron

axon

any long axon is also called a …

nerve fiber

Axon terminals, the … region of the neuron, release … that either excite or inhibit other neurons or effector cells

secretary, neurotransmitter

In motor neurons, the nerve impulse is generated at the …. of the axon

initial segment

ganglion

cluster of neuron cell bodies in the PNS

tract

bundle of axons in the CNS

nerve

bundle of axons in the PNS

nucleus

cluster of neuron cell bodies in the CNS

What is the myelin sheath

fatty insulation

How is the myelin sheath formed in the PNS

Schwann cells

How is the myelin sheath formed in the CNS

Oligodendrocytes

What is the function of the myelin sheath

protects and electrically insulates as well as speed of action potential

What is the structural classification of neurons based on

The number of processes extending from their cell body

what type of neuron is shown

unipolar neuron

What type of neuron is shown

bipolar neuron

what type of neuron is shown

multipolar

what is the functional classification of neurons based on

the direction the nerve impulse travels

transmit impulses from receptors in the skin or internal organs toward the CNS

sensory neurons

shuttle signals through CNS pathways where integration occurs

interneurons

transmit impulses away from the CNS to the effectors of the body

motor neurons

also called association neurons

interneurons

also called afferent neurons

sensory neurons

also called efferent neurons

motor neurons

virtually all are unipolar

sensory neurons

all are multipolar

motor neurons

make up over 99% of the neurons of the body; almost all are multipolar

interneurons

voltage

the measure of potential energy generated by separated electrical charges

current

the flow of electrical charge from one point to another

resistance

the hindrance to charge flow provided by substances through which the current must pass

In the body, the charge separation across the plasma membrane creates a …. across the membrane

potential

In the body, electrical currents reflect the flow of … across the plasma membrane

ions

In the body, the plasma membrane provides … to the flow of current across the membrane

resistance

Ohm’s law

current is (directly or inversely) proportional to voltage

directly

An increase in voltage will (increase or decrease) the current

increase

Current is (directly or inversely) proportional to resistance

inversely

An increase in resistance will (increase or decrease) the current

decrease

what type of membrane ion channel opens when a particular neurotransmitter binds to it

chemically gated channel

what type of membrane ion channel opens and closes in response to changes in the membrane potential

voltage-gated channel

what are the two components that make up the electrochemical gradient

concentration and electrical

describe the component, concentration, in the electrochemical gradient

ions move down

describe the component, electrical, in the electrochemical gradient

ions move towards the area of opposite charge

resting membrane potential

voltage across the plasma membrane. -50 to -90 mV

When a voltmeter shows a value of -70 mV when measuring the resting membrane potential along the axon of a neuron, what does the minus sign mean

Inside plasma membrane is negatively charged relative to outside

The major cation in the extracellular fluid is (Na + or K +)

Na+

The major cation in the intracellular fluid is (Na+ or K+)

K+

The plasma membrane has more leakage channels for (Na+ or K+)

K+

The greater (inward or outward) diffusion of K+ than (inward or outward) diffusion of Na+ makes the voltage on the cytoplasmic side of the plasma membrane potential more (positive or negative)

outward, inward, negative

explain how the actions of the sodium-potassium pump stabilize the resting membrane potential

the RMP would not stabilize

A stimulus causes the membrane potential to change from -70 mV to -65 mV. Does this change represent depolarization or hyper polarization of the membrane?

moves closer to 0 (less negative) depolarization

what are graded potentials

small changes in neuron membrane potential

why are graded potentials important

they help determine whether an action potential will occur

what makes graded potentials “graded”

size varies depend on strength of stimulus

why are graded potentials brief, short distance signals

they weaken with distance

which type of graded potential is produced in a neuron that is stimulated bby neurotransmitter released by another neuron

postsynaptic potential

which typpe of graded potential triggers and action potential in a skeletal muscle cell

end plate potential

graded potential or action potential- always the same amplitude

action

graded potential or action potential- short distance communication only

graded

graded potential or action potential- occurs along the axon

action

graded potential or action potential- involves voltage-gated channels

action

graded potential or action potential- an all or nothing phenomenon

action

graded potential or action potential- occurs at the dendrites and cell body

graded

graded potential or action potential- long distance communication

action

graded potential or action potential- decays with distance traveled

graded

which type of graded potential (depolarizing or hyper polarizing) makes and action potential more likely

depolarizing

in a typical multipolar neuron, where does the transition from local graded potential to a long distance action potential occur

initial segment of axon

what is the term for the voltage at which an axon “fires” an action potential

threshold

state of voltage-gated Na+ channels- resting state

closed

state of voltage gated Na+ channels- depolarization

open

state of voltage gated Na+ channels- repolarization

closed