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Biology > Nervous System > Flashcards

Nervous System Flashcards

1
Q

Nerve

A

A bundle of axons from many individual neurons encased in connective tissue. They transmit signals over long distances between CNS.

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2
Q

Neuron

A

A single nerve cells (the functional unit of the NS) that conducts nerve impulses.

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3
Q

Cephalization

A

Concentrating sensory organs and NS components at the front of the body (the head).

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4
Q

Convergent Evolutions

A

Different species ind. evolving to similar traits. Ex: forward locomotion and predator and prey adaptation

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5
Q

Central nervous system (CNS)

A

–> integration—- brain and spinal cord
-Afferent neurons: sensory neurons that carry informations from sensory receptors to CNS
-Efferent neurons: motor neurons that carry info from CNS to muscles and glands to carry out actions.

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6
Q

Peripheral Nervous System (PNS)

A

-Voluntary vs involuntary
-Cranial and spinal nerves

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7
Q

Sympathetic

A

-“FIGHT OR FLIGHT”
-dilated pupils
-salivatory glands
-heart accelerates
-relaxes bronchi in lungs
-promotes activity in the digestive system
- prevents voiding from the bladder
-inhibits ejaculation and vaginal contractions

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8
Q

Para sympathetic

A

-“REST & DIGEST”
-constricts pupils
-stimulate salivation
-slows heart rate
-constricts bronchi in the lungs
-stimulates activity of pancreas
-stimulate gall bladder
-promotes voiding
-promotes erection of genitals

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9
Q

sensory neuron

A

nerve cell that transmits sensory information to from sensory receptors (touch, sight, taste, smell, and hearing) to CNS

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10
Q

Interneuron

A

Connects Afferent neurons from sensory receptors to Efferent neuron which then goes to a muscle or gland.

Plays key role in spinal cord for processing and integrating information.

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11
Q

Motor neuron

A

Responsible for carrying information from the CNS to muscles or glands.

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12
Q

dendrite

A

receive stimuli

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13
Q

axon hillock “decision point”

A

-Sums synaptic stimuli
-between cell body and axon
- determines in axon potential should be initiated

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14
Q

axon

A

where axon potential is conducted

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15
Q

postsynaptic cell

A

-receives the signal from the presynaptic cell
-has receptors on its membrane
-neurotransmitters bond to these receptors

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16
Q

presynaptic cell

A

-send signal
-has synaptic terminal that contains vesicles filled with neurotransmitters that are released into the synaptic cleft as the result of axon potential

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17
Q

synapse

A

Junction between neurons
- electrical (neurons connected directly by gap junctions) and chemical (chemical messenger transmits info across a space separating the 2 neurons)
-Most synapses in the body are chemical

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18
Q

neurotransmitter

A

chemical substance transmits signals across synapses. Have different effects depending on type of receptor.

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19
Q

membrane potential

A

-Differences in electrical charges across membrane. Creates electrical gradient.
-Crucial for function neurons (like muscle cells)
-Na+, K+, Cl-
-Negative inside and positive outside
-Na+-K+ pump moves Na+ ions out and K+ ions in

20
Q

action potential

A

-rapid temporary change in membrane potential
-When a neuron is sufficiently stimulated (i.e., the membrane potential reaches a certain threshold), voltage-gated channels open, allowing sodium ions (Na⁺) to flood into the cell. This makes the inside of the cell more positive (depolarization).
-After the peak of the action potential, potassium channels open, and potassium ions (K⁺) move out of the cell, returning the membrane potential to a negative value (repolarization).
-If the membrane potential becomes more negative than the resting potential (a state called hyperpolarization), it is restored to the resting potential through the action of ion pumps and channels.

21
Q

resting potential

A

-membrane potential when cell is not sending a signal
- typically, -70 millivolts (mV)

22
Q

threshold potential

A

Potential a cell must be reached for neuron or muscle cells to generate action potential.
- Usually -55 mV

23
Q

depolarization

A

-depolarization of one region of axon stimulates depolarization of next region

24
Q

repolarization

A

-Na+ channels become inactivated (repolarized)

25
Q

Voltage gated Na channel

A
  • when Na channels open, Na+ ions rapidly enter the cell causing a positive spike to membrane potential
    -when voltage rises to +40 mV, Na+ channels close and K+ channels open
26
Q

Voltage gated K channel

A

-K+ channels allow K+ ions to “leak” out of cell, resulting in negative resting potential the inside relative to the outside of the cell
- K+ channel open slower than Na+ channels to K+ ions open much slower

27
Q

Voltage gated Ca channel

A

-Action potential and depolarization of the axon terminal opens these channels
-essential for exocytosis

28
Q

inactivation gate

A

Sodium channels: Inactivation gates close after the peak of an action potential, stopping the flow of sodium ions and the membrane potential from rising further. This creates a refractory period that prevents another action potential from moving backwards

Potassium channels: Inactivation gates cause potassium channels to close spontaneously after opening

29
Q

Na/K pump

A
  • Na+- K+ pump move Na+ ions out of cell and K+ ions in
30
Q

hyperpolarization/refractory period

A

-When K+ channels are open and “overshoot” causing cell membrane to be hyper polarized
-Refectory period is where the nerve can’t fire another action potential

31
Q

glial cell

A
  • non-nueron cell
    -supports, nourishes, and protects nuerons
  • inside myelin sheath
32
Q

Node of Ranvier

A

-at nodes there is a build up of (+) charges inside and (-) charges outside the cell
-action potentials jump from node to node

33
Q

Saltatory propagation

A

-the way action potential travels along myelinated axons in the nervous system. Jumping from node of renvier to another
-saltare=”jump”

34
Q

axon terminal

A

-endpoints that release neurotransmitters to communicate with other neurons or effector cells (like muscles)

35
Q

(neurotransmitter storage) vesicles

A

-membrane bound sacs with in neurons
-40 to 100nm

36
Q

ligand-gated ion channel

A

“chemically-gated ion channel”
-opens in response to binding to LIGAND
-allowing ions to flow in and alter electrical potential
- each dendrite has many different ligands
-each neurons receives unique chemical signals , excitatory and inhibitory

37
Q

Synaptic cleft

A

-space between two neurons
-20 to 40 nm wide

38
Q

Signal transduction pathway

A

-Signal Transduction: An Overview
A signal transduction pathway is a series of molecular interactions that occur when a signaling molecule binds to a receptor, which activates intracellular pathways that are involved in cell signaling

  • Ex) This pathway helps maintain glucose homeostasis by increasing the uptake of glucose into muscle and fat cells, and reducing the synthesis of glucose in the liver.
39
Q

Myelin sheath

A

-a fatty, protein-rich layer that insulates nerve cells in the brain and spinal cord, allowing electrical impulses to travel quickly and efficiently

40
Q

EPSP & IPSP

A

Excitatory/Inhibitory PostSynaptic Potential

41
Q

Spatial summation

A

-EPSPs at 2 or more different synapses set off an action potential

42
Q

afferent vs efferent neurons

A

afferent: sensory neurons that carry info to CNS to muscles from sensory receptors
efferent: motor neurons that carry information from CNS to muscles and glands

43
Q

Somatic vs Autonomic responses

A

Somatic: conscious, sensing and responding to environments, sight, smell, sound etc.,
Autonomic: Unconscious and regulate internal functions and maintain homeostasis

44
Q

Motor endplate

A

-specialize region of muscle fiber membrane (sarcolemma) at the neuromuscular junction
-motor neuron communicates with skeletal muscle fiber
-muscle contraction

45
Q

Acetylcholine

A

-a ligand
-excitatory (depolarization)
-involves Na+

-binds to muscle membrane receptors, causing depolarization of the muscle cell and contraction.

46
Q

afferent vs efferent nerves

A

Afferent nerves carry sensory information towards the central nervous system (CNS), while efferent nerves carry motor commands away from the CNS to muscles and glands

47
Q

reciprocal inhibition (in a reflex circuit)

A

-sensory stimulus (often a stretch) in extensor muscle actives sensory receptors
-sends signal along sensory nerve
-sensory neuron synapses with motor neuron in the spinal cord
-motor neuron sends excitatory signal to same extensor muscle, which contracts
-inhibitory interneuron inhibits contraction of the opposing flexor muscle

Biology (12 decks)

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