MEC322: Nervous System Flashcards by Kate Doyle

Which of the 11 body systems play the most important roles in maintaining homeostasis?

nervous system and endocrine system

How well did you know this?

Not at all

Perfectly

What are the three basic functions of the nervous system?

detecting stimuli (sensory function); 
analyzing, integrating, and storing sensory information (integrative function); 
responding to integrative decisions (motor function).

How well did you know this?

Not at all

Perfectly

What does CNS stand for?

Central nervous system

How well did you know this?

Not at all

Perfectly

What does PNS stand for?

Peripheral nervous system

How well did you know this?

Not at all

Perfectly

What is part of the CNS?

Brain

Spinal cord

How well did you know this?

Not at all

Perfectly

What is part of the PNS?

Cranial nerves
Spinal nerves
Ganglia
Enteric plexuses in small intestine
Sensory receptors in skin

How well did you know this?

Not at all

Perfectly

What are the two divisions of the peripheral nervous system?

Afferent- brings sensory info to CS

Efferent- carries motor commands from CNS to muscles glands etc

How well did you know this?

Not at all

Perfectly

What are the subdivisions in the efferent division?

Somatic nervous system SNS

Automatic nervous system ANS

How well did you know this?

Not at all

Perfectly

What does the SNS provide?

voluntary control over skeletal muscles

How well did you know this?

Not at all

Perfectly

What does the ANS provide?

involuntary control of cardia and smooth muscle, and glands

How well did you know this?

Not at all

Perfectly

What is a neuron cell?

cells specialised for nerve impulse conduction and provide most of the unique functions of the nervous system
e.g. sensing, thinking remembering, controlling muscle activity

How well did you know this?

Not at all

Perfectly

What is a neuroglia cell?

they support, nourish and protect the neurons and maintain homeostasis in the interstitial fluid that bathes neurons

How well did you know this?

Not at all

Perfectly

What are the three parts of a neuron?

Dendrites
Cell body
Single axon

How well did you know this?

Not at all

Perfectly

What is the dendrite in a neuron?

main receiving or input region

How well did you know this?

Not at all

Perfectly

What is the cell body in a neuron?

integration occurs here

How well did you know this?

Not at all

Perfectly

What is the axon in a neuron?

output part

conducts nerve impulses towards another neuron, muscle fibre or gland cell

How well did you know this?

Not at all

Perfectly

Structurally what are the three classifications of neuron?

multipolar, –|–o <
bipolar, -|-o– <
unipolar –o-|-

How well did you know this?

Not at all

Perfectly

How are neurons classified functionally?

Sensory neurons
Motor neurons
Interneurons

How well did you know this?

Not at all

Perfectly

What do sensory neurons do?

carry sensory info into the CNS

approx 10^6

How well did you know this?

Not at all

Perfectly

What do motor neurons do?

carry info out of CNS to effectors (muscles and glands)

approx 500000

How well did you know this?

Not at all

Perfectly

What do interneurons do?

located within the CNS between sensory and motor neurons

approx 20^9

How well did you know this?

Not at all

Perfectly

How much of the CNS do the neuroglia make up?

Study These Flashcards

half the volume of the CNS

What are the neuroglia in the CNS?

Study These Flashcards

astrocytes, oligodendrocytes, microglia, and ependymal cells

What are the neuroglia in the PNS?

Study These Flashcards

Schwann cells and satellite cells

What are myelin sheaths?

sleeves of fatty tissue that protect your nerve cells

Which two types of neuroglia produce myelin sheaths?

Oligodendrocytes myelinate axons in the CNS, and Schwann cells myelinate axons in the PNS.

What do astrocytes do? | Neuroglia cells in CNS

- Control the chemical environment of the brain - Brace neurons and form barrier against capillaries - Abundant, star-shaped cells

What do microglia do? | Neuroglia cells in CNS

- Spiderlike phagocytes | - Dispose of debris

What do ependymal cells do? | Neuroglia cells in CNS

- Line cavities of the brain and spinal cord | - Cilia assist with circulation of cerebrospinal fluid

What do oligodendrocytes do? | Neuroglia cells in CNS

- Wrap around nerve fibers in the central nervous system | - Produce myelin sheaths

What do Satellite cells do? | Neuroglia cells in PNS

Protect neuron cell bodies

What do Schwann cells do? | Neuroglia cells in PNS

Form myelin sheath in the peripheral nervous system

How to neurons communicate with one another?

nerve action potential AKA nerve impulses

What does generation of action potentials depend on?

the existence of a membrane potential and the presence of voltage-gated channels for Na+ and K+.

What is the resting membrane potential?

RMP= -70mV | inside of the neuron is 70 mV less than the outside

What causes the RMP?

an unequal distribution of ions on either side of the plasma membrane and a higher membrane permeability to K+ than to Na+. The level of K+ is higher inside and the level of Na+ is higher outside, a situation that is maintained by sodium–potassium pumps.

What happens during an action potential?

- voltage-gated Na+ and K+ channels open in sequence - results in depolarisation ( the loss and then reversal of membrane polarisation) - opening of voltage-gated k+ allows depolarisation and recovery of the membrane potential

What is the all-or-none principal?

if a stimulus is strong enough to generate an action potential, the impulse generated is of a constant size

Can another action potential be generated during the refractory period?

What is nerve impulse conduction that occurs as a step-by-step process along an unmyelinated axon called?

continuous conduction

What is saltatory conduction?

a nerve impulse “leaps” from one node of Ranvier to the next along a myelinated axon.

What conducts impulses faster, large diameter axon or small diameter?

large

What conducts impulses faster, myelinated axons or unmyelinated axons ?

myelinated axons

What is a node of Ranvier?

a gap in the myelin sheath of a nerve, between adjacent Schwann cells.

How do neurons communicate with other neurons and effectors?

at synapses in a series of events known as synaptic transmission

What are the two types of synapses?

electrical and chemical

Describe an electrical synapse

nerve impulses are conducted between adjacent neurons via gap junctions. This type of synapse is found in visceral smooth muscle, cardiac muscle and the brain.

Describe a chemical synapse

the presynaptic neurons release neurotransmitters which will bind to receptors on the plasma membrane of the postsynaptic neuron. At a chemical synapse, there is only one-way nerve impulse conduction.

What does the excitatory neurotransmitter do?

depolarizes the postsynaptic neuron’s membrane, brings the membrane potential closer to threshold, and increases the chance that one or more action potentials will arise.

What does the inhibitory neurotransmitter do?

hyperpolarizes the membrane of the postsynaptic neuron, thereby inhibiting action potential generation.

What are the three ways a neurotransmitter can be removed?

diffusion, enzymatic destruction, and reuptake by neurons or neuroglia.

List some important neurotransmitters

acetylcholine, glutamate, aspartate, gamma aminobutyric acid (GABA), glycine, norepinephrine, dopamine, serotonin, neuropeptides, and nitric oxide.

What happens when we want to move?

, electrical signals cascade from the brain down the spinal cord to instruct our muscle to contract

MEC322: Nervous System Flashcards

(53 cards)