Chapter 3: Nervous and Endocrine Systems

what entire nervous system is divided into ____ and _____

central nervous system and peripheral nervous system

the central nervous system consists of _________

the brain and spinal cord

the peripheral nervous system consists of _____ and conists of _______ and ______ nervous system

everything except brain and spinal chord

somatic and autonomatic nervous system

the somatic nervous system under the peripheral nervous system is involved in ______

involved in voluntary behavior, such as when you read for an object

the autonomic component of the peripheral nervous system is responsible for _____

less voluntary actions, such as controlling heart rate and other bodily functions

on a broad level, how does the CNS and PNS interact

the PNS sends signals to the CNS, and the CNS organizes and evaluates the info to direct the PNS on what to do

what is the nervous system

body’s master command and communication center that coordinates all actions, thoughts, and automatic functions via electrical and chemical signals

the basic unit of the nervous systems are ________ cells called ______

nerve cells called neurons

what are neurons

• basic unit of the nervous system

• nerve cells

• nerve cells that receive, integrate (assessing), and transmit information

neurons are powered by ____________ and communicate with each other via _______

• electrical impulses

• chemical signals

what are sensory neurons

detect information from the real world and pass it along to the brain

what are somatosensory nerves

detect information from the skin and muscles

what do motor neurons do

direct muscles to contract or relax, producing movement

what are interneurons

act as relay stations so motor neurons and sensory neurons can communicate

sensory neurons and motor neurons comunicate via _____

interneurons

a typical neuron has ___ (#) of structural regions that participate in communication functions, and those are:

1. dendrites

2. cell body

3. axon

4. terminal buttons

what is the purpose of dendrites

receive and transmit information from other neurons to the cell body

what is the purpose of the cell body

place on a neuron where the information received from the dendrites is collected and integrated

what is the axon

part of the neuron where electrical impulses are transmitted

what is a nerve

a bundle of axons that carry information between the brain and other specific locations of the body

what are terminal buttons

end of the axon, small nodules that release chemical signals from the neuron into the synapse

what is the synapse

• site where chemical communication occurs

• region between the terminal buttons of the sending neuron and the dendrites of the receiving neuron

what is the action potential

the electrical signal that travels along the axon and causes the release of chemical signals via the terminal buttons

what is resting membrane potential

the electrical voltage difference across a neuron’s cell membrane when it is not active

what does it mean for a neuron to be polarized

it has more negative ions on the inside than on the outside

two types of ions that contribute to a neuron’s resting membrane potential are:

sodium and potassium ions

the Na-K pump (increases/decreases) sodium and (increases/decreases) potassium

• decreases sodium

• increases potassium

when signals arrive at the dendrites by the thousands, they are of two types _____ signals and ______ signals

excitatory signals and inhibitory signals

what do excitatory signals do

• depolarize the cell membrane

• decrease the negative charge inside the cell relative to the outside

• increase the positive ions

• move from -70mV to -50 mV (example)

what do inhibitory signals do

• increase the negative ions

• move from -49 mV to -82 mV (example)

about what voltage is required for action potential

when the voltage is greater than (more positive) than -55mV

describe how pumps work when an action potential is generated

1. Na rushes into the cell (making the inside more positive) and firing an action potential

2. K rush out the cell

3. Na then closes and K pumps out → inside of cell even more negative

4. relative refractory period (brief period after action potential where membrane potential is even more negative/hyper polarized making it harder to fire)

5. Na/K pump resets to membrane potential to resting state

what is the relative refractory period

brief period after Na pump closes and K are being pumped out where the cell’s membrane potential is more negative/hyper polarized than the cell’s resting membrane potential

what is the all-or-none principle

states that a neuron fires with the same potency each time

it either fires or it doesnt’t

if you have a stronger stimulation, how can you tell via neurons

the neurons are activated more/fired more frequently (with the same strength of course)

what is the absolute refractory period

the brief period of time following an action potential in which a channel cannot be opened (a cooldown)

what are myelin sheaths? they are made of ______

• myelin sheaths encase and insulate many axons

• they are made glial cells

what are the segments between myelin sheats called?

nodes of Ranvier

electric signals jump along the ______

nodes of Ranvier

where are the ion channels located

in the nodes of Ranvier

how do myelin sheaths’s insulation decrease message transfer time

by preventing electrical leaks and forcing jumps via the nodes of Ranvier

what are pre/post synaptic neurons

• pre = sending signal

• post = receiving signal

what are neuroransmitters

chemical substances that transmit signals from one neuron to another

where are neurotransmitters made? where are they stored?

made in the axon or cell body and stored in vesicles

NEEDS TO BE ADDED

NEEDS TO BE ADDED: TABLE 3.1

what are receptors

specialized protein structures in the post-synpatic neuron where specific neurotransmitters bind to

what are the (#) ways a neurotransmitters influence is terminated. explain each one

1. reuptake (neurotransmitter is taken back into the presynaptic neuron

2. enzyme deactivation (an enzyme in the synapse destroys the neurotransmitter)

3. autoreception (neurotransmitter binds to a receptor/specialized protein structures to determine how much of the neurotransmitter is inside the synapse → results in more/less being produced by neuron)

drugs and toxins that enhance the actions of neurotransmitters are called ______

agonists

drugs and toxins that inhibit the actions of neurotransmitters are known as ______

antagonists

3 ways an agonist works

1. introduces a substance that produces the neurotransmitter

2. blocks the receptors for reuptake

3. mimck the actions in the postynaptic cell

3 ways antagonists work

1. introduce a substance that reduces the amount of neurotransmitter made and released into the synapse

2. introduces a substance that facilitates the destruction or breaking down of the neurotransmitter

3. blocks postsynaptic receptors

in the somatic nervous system:

____, _____, and _____ send signals to the spinal chord and brain(CNS)

skin, muscles, and joints

in the somatic nervous system, the spinal chord and brain send signals to the _____, _____, and ______

muscles, joints, and skin

in the autonomic nervous system, _____ and ______ send signals to the spinal chord and brain

glands and internal organs

the the autonomic nervous system the brain and spinal chord send signals to the ______ and ______

glands and internal organs

the sympathetic divison is a division of the ______ and _____

• autonomic system

• prepares body for action

the parasympathetic division is a part of the ________ and ______

• autonomic nervous system

• returns body to resting state

what is the endocrine system

communication network that influences thoughts, behaviors, and actions

the endocrine system is (faster/slower) than the nervous system and uses ____ to communicate

slower, hormones

what are hormones

chemical substances released into the bloodstream by the endocrine glands

the endocrine system is primarily controlled by the ______ (think lobes/subcortical areas)

hypothalamus

the body’s master control gland is the _________

pituitary glands