A & P nervous system flashcards

what two parts is the nervous system divided into?

• CNS

• PNS

What is the PNS comprised of?

• all other nerves that are in the brain or the spinal cord.

What is the CNS comprised of?

consists of the brain and the spinal cord.

clinical application: Migraine

signs: pounding head, nausea, aura light or sound sensitivity

treatment: drugs that block neurotransmitter release from certain neurons

What is sensory division (Afferent)?

• sends impulses from the senses to the CNS

What is motor division (Efferent)

• sends impulses from the CNS to the muscles and the glands

Sympathetic vs Parasympathetic?

• Symp: used in emergency situations (fight or flight)

• Parasymp: reduces sympathetic response and provdies resting functions

Autonomic vs Somatic?

• Auto: involuntary muscle control

• Soma: voluntary muscle control

NS: sensory input

it detects changes inside and outside the body

NS: Integration

processing and interpreting the information

NS: Response

activation of muscles (motor output) or glands

What are the 2 types of nerve cells

• Neurons: conduct impulses around the body

• Neuroglia: support, insulate, and protect neurons

What percent of nerve cells do neurons make up?

10%

What percent of nerve cells do neuroglia make up?

90%

what does the cell body of a neuron contain?

1. nucleus

2. cytoplasm

3. organelles

what is a dendrite?

• brings impulses towards the cell body

• (the little branches protruding off the neuron)

What is an axon?

• send impulses away from the cell body

• (the long chain which follows the flow of nerve impulses)

What is an axon terminal?

• they release neurotransmitters to pass an impulse to the next neuron.

What are the 3 types of neurons?

• unipolar: one process

• bipolar: two processes

• multipolar: many processes

What are the 3 types of neuron functions?

• afferent neurons:  carry impulses towards the CNS

• efferent neurons: carry impulses away from the CNS

• interneurons: connect afferent and efferent neurons

what are axons wrapped in?

• Myelin, which is like a waxy insulation → helps nerve impulses to travel more quickly.

how is a myelin formed?

a Schwann cell wraps itself around axon, like a coil.

(^ outside layers of a schwann are called a neurilemma)

what are the myelin wrappings called?

myelin sheath; since this is formed from many Schwann cells, it has gaps called Nodes of Ranvier

What are satellite cells?

• support clusters of neuron cell bodies (ganglia)

what are astrocytes?

support and anchor neurons to surrounding capillaries

what are microglia?

provide immune response to the CNS

what are ependymal cells?

secrete and circulate cerebrospinal fluid

what are oligodendrocytes?

provide myelin insulation to neurons in the CNS

How is a nerve impulse passed along a neuron?

• an electrical signal that travels along the neuron. It arises from the movement of ions causing a change in electrical charges.

What happens when a neuron is at rest?

• its intracellular space is negatively charged and the extracellular space is positively charged. this is called resting potential

What happens when a neuron is stimulated?

• Sodium rushes into the neuron and quickly reverses the charges (depolarization) → this is known as an action potential

• ^ This process moves down the length of a neuron

what happens as an impulse passes (neuron stimulated)

• potassium diffuses put of the neuron (re polarization)

• then, the sodium-potassium pump then restores the ion concentrations to normal and the resting potential returns.

What are the steps of a nerve impluse

 1. impulse arrives and threshold is met → 2. voltage gated Na+ channels are opened and Na+ enters the cell → 3. voltage gated K+ channels are opened and K+ leaves the cell; Na+ begin to rest → 4. channels ( K+) are still open; while Na+ are at resting state → 5. Na+/K+ pump restores orginial levels of voltage in the cell.

What event occurs at the synapse?

• where two neurons meet

• these two neurons do not touch, the space between them is called the synaptic cleft.

T OR F: does the impulse cross the axon terminal once it reaches?

FALSE; it does not cross the gap

what does the impulse stimulate?

• the vesicle to release the neurotransmitters across the synaptic cleft

• these neurotransmitters cause channels to open in the next neuron, continuing the action potential from one neuron to the next.

overview steps of synaptic transtion? (cards: 36,35,34)

1. action potential arrives at presynaptic terminal

2. Ca2+ channels open on presynaptic terminal

3. synaptic vesicles release neurotransmitters

4. neurotransmitters bind to receptors on the postsynaptic neuron

5. Na+ channels open on the posthypnotic neuron

what are the structures protected by three layers of connective tissue called the meninges

• dura mater: thick, tough layer

• arachnoid membrane: thin, cobweb-like layer

• pia mater: thin layer containing lots of blood vessels

where is the cerebrospinal fluid and what is its function?

• between the arachnoid layer and the pia matter

• it protects the brain by preventing it from contacting the skull.

• it also maintains the blood-brain barrier (this controls homeostasis for the brain and prevents infection

how many ventricles are in the CSF system

• 4 ventricles 

• 2 lateral

How is the myelin sheath created?

• from a Schwann cell; this wraps itself around the axon like a coil.

• The outer layers of a Schwann cell are called the neurilemma.

What is the overall purpose of a myelin?

• they help nerve impulses travel more quickly

• provide insulation

What are Satellite cells? What are Schwann cells?

• Support clusters of neuron cell bodies (ganglia) → in the PNS

• Provide myelin insulation → in the PNS

Where are neuroglia found?

• Either in the CNS or the PNS

What is the #1 kind of neuroglia in the CNS that supports and anchors neurons to surrounding capillaries?

• Astrocytes

What is the #2 kind of neuroglia in the CNS that provides immune response?

• Microglia

What is the #3 kind of neuroglia in the CNS that secretes and circulate cerebrospinal fluid?

• Ependymal cells

What is the #4 kind of neuroglia in the CNS that provides myelin insulation to neurons?

• Oligodendrocytes