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Biology Unit 3 > Unit 1: Nervous System > Flashcards

Unit 1: Nervous System Flashcards

0
Q

What is a feedback system?

A

The way your body detects one of its systems has deviated from it’s “set point” (normal). Can be negative or positive

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1
Q

What is homeostasis?

A

The steps your body takes to maintain a constant internet all environment despite changes in the external environment
Your body strives to keep many internal conditions within a range of normal values

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2
Q

What are the components of a feedback system?

A

Sensor - detects a change
(Nerve signals control centre)
Control centre - compared the change to the “set point”
(Nerve signals effector)
Effector - responds, adjusting the system back to the “set point”

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3
Q

Example of positive feed back system…

A

Childbirth

Sensor - cervix pressure sensors
Control center - brain
Effector - pituitary gland releases oxytocin which makes the uterus contract and pushes baby’s head onto the cervix

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4
Q

What is a positive feedback loop?

A

The change in internal conditions that cause it to keep changing, less common in the body

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5
Q

What is a negative feedback loop?

A

Once normal is reached, this is detected and the signal to change is stopped, more common in the body

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6
Q

Example of negative feedback system…

A

Body temperature

Sensor - brain temperature sensors
Control center - brain
Effector - blood vessels dilate and sweat glands are activated to lower body temperature

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7
Q

What is the central nervous system?

A

The control center in the maintenance of homeostasis…

  • the brain
  • the spinal cord
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8
Q

What is myelinated tissue?

A

“White matter” that conducts impulses quickly

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9
Q

What is unmyleinated tissue?

A

“Grey matter” that conducts impulses slowly

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10
Q

What is the brain composed of?

A
  • myelinated tissue (white matter) on the inside

- unmyelinated tissue (grey matter) on the outside

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11
Q

What is the spinal cord composed of?

A
  • myelinated on the outside

- unmyelinated on the inside

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12
Q

What are meninges?

A

The entire CNS is covered by meninges, a triple layer of tough elastic membranes

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13
Q

What are the names of the layers of the meninges?

A

Outer layer = dura Mayer
Middle layer = arachnoid
Inner layer = periosteal (pia)

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14
Q

What do the meninges do?

A
  • creates a blood brain barrier that only allows certain substances from the blood to enter the brain (positive or negative) such as glucose, oxygen; caffeine, alcohol (flaw), while keeping others out, toxins and infections
  • acts as a shock absorber due to the presence of cerebrospinal fluid between each layer
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15
Q

What does the cerebrospinal fluid do?

A

Acts as a shock absorber between each layer of meninge, provides cushion between the brain and the cranium (skull)

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16
Q

What does the brain contain?

A

Over 100 billion nerve cells, each having 10 000 connections to other nerve cells

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17
Q

What is the brain protected by?

A

The cranium (skull)

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18
Q

How are sutures beneficial?

A

The craniums large size, each at birth, is compensated for by sutures in the cranium, which allow it to compress in the birth canal (some sutures don’t full close until the age of 6, creating soft spots on the head)

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19
Q

What is the cerebellum?

A
  • “little brain”

- co ordination and proprioception (balance)

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20
Q

What is the medulla oblongata?

A

Automatic regulation of breathing, heart rate, coughing, etc…

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21
Q

What is the pons?

A

Relay center between many brain areas (receive signals, sends signals)

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22
Q

What is the midbrain?

A

Processes information from eyes, nosed ears and controls muscles

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23
Q

What is the thalamus?

A

Relay center between many brain areas

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24
Q

What is the hypothalamus?

A

Controls basic drives (hunger, thirst, emotions, etc..)

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25
Q

What is the ventricle?

A

Stores and produces cerebrospinal fluid

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26
Q

What is the corpus callosum?

A

Links the right side of the brain to the left side

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27
Q

What is the right side responsible for?

A

Intuitive thinking, artistic ability

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28
Q

What is the left side responsible for?

A

Sequential thinking, language, math

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29
Q

What is the cerebral cortex?

A

4 lobes on each side of the brain, outer layer of the brain

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30
Q

What is the temporal lobe?

A

Auditory area

31
Q

What is the frontal lobe?

A

Integrates critical thinking, memory, personality, fine motor skills, the art of speaking

32
Q

What is the parietal lobe?

A

Sensory information from skin and taste buds (taste an touch)

33
Q

What is the occipital lobe?

A

Visual area (eyes)

34
Q

What is meningitis?

A

Inflammation of the meninges, caused by viral or bacterial infection, fungi or parasites. Tested for by a lumbar puncture.

35
Q

Why is meningitis tested through a lumbar puncture?

A

Blood tests would not show anything because the meninges separate from the blood through the blood brain barrier

36
Q

What is a lumbar puncture?

A

Long, thin needle is inserted into the spinal canal between the meninges to sample the cerebrospinal fluid to test for bacteria and viruses

37
Q

What is an epidural?

A

Regional anaesthetic, where the drug is injected around the nerves that carry signals from the part of the body that feels pain during labour. It numbs the tummy, providing very effective pain relief. It is inserted in the lower back by a needle that goes into the space between the layers of tissue in the spinal coloumn, the epidural space. The nerves are temporarily stopped from processing (working). The risks include bleeding, infection, headache, nerve damage or paralysis

38
Q

What is the spinal cord?

A

A column of nerve tissue extending from the brain, protected by the vertebrae which acts as a ribcage for the spinal cord. At each vertebrae, sensory nerves come in and go up to the brain and motor nerves come out and go to the rest of the body

39
Q

Anatomy of the spine…

A 
Cervical = 7 bones 
Thoracic = 12 bones 
Lumbar = 5 bones 
Sacrum = 1 bone (it's own bone) 
Coccyx = 1 bone
40
Q

What is the peripheral nervous system?

A

Carriers information to and from the central nervous system (brain and spinal cord)
Made of nerves

41
Q

What are the three types of nerves?

A

Sensory nerves, motor nerves and interneuron nerves

42
Q

What is a sensory nerve?

A

Carriers information in to the central nervous system (spinal cord)

43
Q

What is the interneuron?

A

A nerve contained within the spinal cord that interprets the information coming in (also known as association neuron) … Takes the information up to the brain and brings back a message

44
Q

What is a motor nerve?

A

Carriers instructions out the central nervous system (spinal cord) to the body

45
Q

What is a reflex arc?

A

Information goes from a sensory neuron to the interneuron to the motor neuron without the CNS processing it (therefore they are not under our conscious control)

46
Q

What are the two nerve types of the peripheral nervous system?

A

Somatic motor nerves and autonomic motor nerves

47
Q

What is a somatic motor nerve?

A

Under your control (ex. Nerve to skeletal muscle)

48
Q

What is an autonomic motor nerve?

A

Are controlled by the hypothalamus and medulla oblongata automatically

49
Q

What are the two types of autonomic motor nerves?

A

Sympathetic and parasympathetic nerves

50
Q

What is a sympathetic nerve?

A

Gas pedal, responds to increased physical and emotional stress (ex. Dilated pupils, increased heart rate, decreased salvia)

51
Q

What is a parasympathetic nerve?

A

Brake, responds to decreased physical and emotional stress (ex. Constricted pupils, decreased heart rate, increased salvia)

52
Q

Purpose and risk of parasympathetic?

A

Sympathetic nerves are great motivation but if they are turned on too much, from too much stress, they can cause many illnesses and sicknesses as it weakens the immune system)

53
Q

What is a nerve?

A

Chain or nerve cells (neurons which have the ability to transmit electrical impulses - signals)

54
Q

The structure of a nerve…

A
  • impulses always go in the same direction (from dendrites - head to the axon terminals - tail)
  • nerves are always found in a chain from head to tail
55
Q

What are dendrites?

A

Brings information into the nerve cell

56
Q

What is the cell body?

A

Contains organelles … Brings impulses in, then send the impulse down the axon

57
Q

What is the axon?

A

Carriers impulse outward to it’s ends - the terminals - where it connect to organs, glands or another nerve with a synapse

58
Q

What is the synapse?

A

Microscopic space between two nerve cells which impulses pass

59
Q

What are Schwann cells?

A

Fatty cells which wrap themselves around the axon to create the myelin sheath and white matter, helps transmit impulses faster

60
Q

What is the benefit of Schwann cells (the myelin sheath)?

A

Transmits impulses faster

61
Q

What are the nodes of ranvier?

A

Gaps between the Schwann cells

62
Q

What is the resting potential or a nerve?

A

When no impulses are traveling down the neuron, it maintains a charge difference across the cell membrane due to the action of the sodium, potassium pump which causes the inside of the neuron to be negative (-70mV) relative to the outside

63
Q

What takes place through the sodium potassium pump?

A

3 Na are pumped out of the cell for every 2 K pumped in

64
Q

What is the specific charge of the resting potential?

A

-70mV

65
Q

What is the action potential?

A

The transmission of a nerve impulse (fires)
All of nothing event
Happens in a few milliseconds
Occurs in this direction always (dendrites –> cell body –> axon –> terminals)

66
Q

How many steps are there for an action potential of a nerve? What are they?

A

6 steps:

  • stimulus
  • threshold potential
  • depolarization
  • action potential
  • repolarization
  • refractory period
67
Q

What is step 1 and 2 of action potential?

A

Stimulus: neurotransmitters travel through the synapse from the adjacent nerve and causes the charge in the nerve to raise to about -50mV … This is known as the threshold potential

68
Q

What is step 3 for action potential?

A

Depolarization: voltage gated Na + channel open, allowing sodium to rush back in, making the neuron more positive (Na in)

69
Q

What is step 4 of an action potential?

A

Action potential: reached at +40, the sodium channels close and potassium channels then open allowing potassium to rush back out and make the neuron more negative again (hitting max charge) (K out)

70
Q

What is step 5 of an action potential?

A

Once the neuron is at -90mV all voltage gated channels close

71
Q

What is step 6 of an action potential?

A

Refractory period: the regular sodium potassium pump restores the resting potential at -70mV again, no new impulses can be transmitted during these few milliseconds nor can the impulse travel backwards (Na / K pump resets back to resting charge)

72
Q

What is salatory conduction?

A

In axons that are myelinated, the impulse jumps between nodes or ranvier and therefore the impulse travels quicker

73
Q

Once the impulse reaches the axon terminal…

A

It has to cross a synaptic cleft to the synapse to another neuron

74
Q

What are neurotransmitters?

A

Chemicals that carry the impulse across the cleft (ex. Dopamine)

75
Q

Dendrites of the next neuron…

A

Receive the neurotransmitter and then the impulse may continue, may slow down, may speed up, etc…

76
Q

Abnormal production of neurotransmitters is linked…

A

To many mental illnesses such as depression, bi-polar disorder, schizophrenia, etc…

Biology Unit 3 (3 decks)

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