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DAT > Biology - Chapter 11.4: Nervous System > Flashcards

Biology - Chapter 11.4: Nervous System Flashcards

1
Q

Axon hillock

A
  • Area where the axon is connected to the cell body

- Responsible for summation of graded potentials

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2
Q

Myelin sheath

A
  • Fatty insulation of the axon that speeds up action potential propagation by stopping ion exchange
  • CNS: oligodendrocytes
  • PNS: Schwann cells
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3
Q

Nodes of ranvier

A
  • Gaps between myelin sheath where ion exchange occurs

- Propagation of action potential occurs here

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4
Q

Saltatory conduction

A

Propagation of action potential along myelinated axons from one node of Ranvier to the next node

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5
Q

Steps of an Action Potential

A

1) At resting potential, membrane potential is around -70 mV and is maintained by Na+/K+ ATPases (3 Na+ ions out, 2 K+ ions in). K+ leak channels also maintain resting potential.
2) Stimulus causes threshold potential reached (-55mV), voltage-gated Na+ channels open, resulting in depolarization = action potential.
3) Repolarization occurs as voltage-gated K+ channels open, letting K+ out. Membrane potential becomes negative again.
4) Hyperpolarization occurs as the membrane potential becomes even more negative than normal resting potential. Results in a refractory period = no action potential can be fired.
5) Membrane potential returns to normal resting potential through the pumping of Na+/K+ ATPases and K+ leak channels

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6
Q

Absolute refractory period

A
  • No other action potential can be fired, no matter how powerful
  • Due to the inactivation of voltage-gated Na+ channels after they open
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7
Q

Relative refractory period

A

-A stronger stimulus could cause another action potential to fire

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8
Q

Steps of Synaptic Transmission

A

1) Action potential reaches presynaptic axon knob, opening voltage-gated calcium channels and releasing Ca2+ ions into neuron
2) Ca2+ ions cause synaptic vesicles to fuse and undergo exocytosis: releasing neurotransmitters into synapse
3) Neurotransmitters bind to ligand-gated ion channels, producing a graded potential
4) Graded potentials summate at the axon hillock and a potential action potential is fired if threshold potential is reached.

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9
Q

EPSP

A
  • Excitatory postsynaptic potential
  • graded potential that depolarizes membrane
  • Na+ ion gates to open and let Na+ ions flow into the cell
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10
Q

IPSP

A
  • Inhibitory postsynaptic potential
  • graded potential that hyperpolarizes the membrane
  • K+ ion gates open and let K+ ions flow out of cell
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11
Q

Microglial cells

A

Macrophages that protect the CNS

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12
Q

Macroglial cells

A
  • Astrocytes
  • Schwann cells (PNS)
  • Oligendrocytes (CNS)
  • Satellite cells
  • Ependymal cells
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13
Q

Astrocytes

A
  • Form the blood-brain-barrier
  • help recycle neurotransmitters
  • provide blood supply to CNS
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14
Q

Satellite cells

A
  • help recycle neurotransmitters

- provide blood supply to PNS

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15
Q

Ependymal cells

A

-secrete cerebrospinal fluid which cushions the CNS

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16
Q

Frontal lobe

A
  • Higher function processes such as decision making, problem solving, judgement, planning ahead, consequences
  • Works with limbic system for memories and emotions
  • Attention/concentration
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17
Q

Temporal lobe

A
  • Speech/language

- Hearing

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18
Q

Occipital lobe

A

-Vision

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19
Q

Parietal lobe

A
  • Spatial/visual perception

- Touch/pain/temperature sensation and integration

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20
Q

Cerebellum

A

Responsible for coordination of movement

21
Q

Brainstem

A
  • Midbrain (relays senses)
  • Pons (relays messages from cerebellum to forebrain)
  • Medulla oblongata (heart/breathing rate, blood pressure, toxin sensing)
22
Q

Thalamus

A

Relay center

23
Q

Limbic system

A

-emotion/memory/learning/motivation

  • Hypothalamus
  • Hippocampus
  • Amygdala
24
Q

Sensory (afferent) neurons

A

-Send signals to the spinal cord and the brain via dorsal roots

25
Q

Motor (efferent) neurons

A

-Send signals back out to the muscles through ventral roots

26
Q

Meninges

A

-Protects the brain, has 3 layers (outermost –> innermost):

Dura mater–> arachnoid –> pia mater

27
Q

Peripheral Nervous System Division

A
  • Somatic (voluntary motor action and sensory input)

- Autonomic (involuntary)

28
Q

Nociceptors

A

pain receptors

29
Q

Autonomic Nervous System Division

A
  • Sympathetic (fight or flight)

- Parasympathetic (rest and digest)

30
Q

Sympathetic Nervous System

A
  • Releases sugar into body for energy
  • Increases heart rate for oxygen delivery
  • Dilation of lungs and pupil
31
Q

Parasympathetic Nervous System

A
  • Relaxation of muscles
  • Decrease in heart rate
  • Maintenance of homeostasis
  • Increase in gastrointestinal activity
32
Q

Sympathetic Nervous system Pre/Postganglionic

A
  • short preganglionic nerves and long postganglionic nerves
  • uses acetylcholine for preganglionic
  • uses noradrenaline/adrenaline for postganglionic
33
Q

Parasympathetic Nervous system Pre/Postganglionic

A
  • long preganglionic nerves and short postganglionic nerves
  • uses acetylcholine for both
34
Q

Outer Ear

A

-Takes in sound waves and the tympanic membrane transfers the sound from outer ear to middle ear

35
Q

Middle Ear

A
  • Composed of three bony ossicles –> malleus, incus & stapes
  • Ossicles transfer vibrations through the middle ear and amplify the signal
  • Stapes transfers vibrations from middle ear to inner ear via the oval window
36
Q

Cochlea

A

Uses fluid and hairs to convert mechanical signal into a neuronal signal, known as transduction

37
Q

Round window

A

Membrane covered opening between middle ear and the inner ear, helps fluid expand and vibrate

38
Q

Semicircular canals

A

Fluid and hairs just like cochlea, gives information about the person’s movement and balance

39
Q

Cornea

A
  • Transparent

- Focuses light and protects the eye

40
Q

Iris

A

-Controls the size of the pupil

41
Q

Pupil

A

-Controls how much light enters

42
Q

Lens

A

-Focuses images on retina

43
Q

Retina

A

-Back of the eye that has photoreceptors (rods and cones)

44
Q

Fovea

A

-Highest concentration of photoreceptors in the retina and responsible for high acuity vision

45
Q

Amacrine and bipolar cells

A

Take information from rods and cones, transmitting the information to ganglion cells of the optic nerve fibers

46
Q

Optic nerve

A

Bundle of axons that transmit visual information to the brain

47
Q

Optic disk

A

Blind spot of the eye, where the optic nerve passes through to reach the brain

48
Q

Sclera

A

Protective connective tissue that surrounds the eye, the white part of the eye

49
Q

Choroid

A

Vascular connective tissue

DAT (16 decks)

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