Cell Types, Injury & Repair, Damage & Death Flashcards

1
Q

What is the nervous system?

A

Body’s command centre. Originating from brain, controls movement thoughts & automatic responses to outside world. Also controls other
body systems & processes, ie. digestion, breathing & sexual development (puberty).

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2
Q

The nervous system can be separated into the ____________________ & _____________________

A
  • Central Nervous System (CNS)
  • Peripheral Nervous System (PNS)
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3
Q

What does the Central Nervous System (CNS) consist of?

A

The brain & spinal cord.

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4
Q

What are the primary functions of the CNS?

A

It receives, interprets, & responds to body tissues.

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5
Q

What role does the hypothalamus play in the CNS?

A

It regulates the autonomic nervous system and basic physiological functions such as growth, respiration, sleep, digestion, excretion, & homeostasis.

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6
Q

How does the CNS contribute to personality?

A

Through learning, cognition, & memory, which form individual differences in characteristic patterns of thinking, feeling, & behaving.

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7
Q

What does the Peripheral Nervous System (PNS) consist of?

A

The nervous system outside the brain & spinal cord, including cranial nerves, spinal nerves, their roots & branches, peripheral nerves, & neuromuscular junctions.

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8
Q

What is the boundary between the Central Nervous System (CNS) & the Peripheral Nervous System (PNS)?

A

The intervertebral foramen.

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9
Q

What are cranial nerves?

A

Nerves that emerge directly from the brain, part of the PNS.

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10
Q

What are spinal nerves?

A

Nerves that emerge from the spinal cord, part of the PNS.

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11
Q

What are the two main categories of cells in the Central Nervous System (CNS)?

A

Neurons & Neuroglia.

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12
Q

What is the basic working unit of the brain called?

A

A neuron.

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13
Q

What are the main components of a neuron?

A

Cell body (soma), axon, & dendrites.

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14
Q

What is the function of dendrites?

A

They receive messages from other neurons.

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15
Q

How do neurons send signals?

A

Using action potentials, which are shifts in the neuron’s electric potential due to the flow of charged particles.

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16
Q

What are the types of neurons based on their structure?

A

Unipolar, bipolar, pseudounipolar, & multipolar.

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17
Q

What characterizes unipolar neurons?

A

They have only one process & are mostly found in invertebrates.

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18
Q

Where are bipolar neurons commonly found?

A

In sensory organs such as the retina, olfactory epithelium, & auditory system.

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19
Q

What is unique about pseudounipolar cells?

A

They have two processes that fuse during development into one short axon, allowing rapid signal transmission.

20
Q

What are multipolar neurons characterized by?

A

Many dendrites originating from different regions of the cell body; they are the most common type in the CNS.

21
Q

What are neuroglia?

A

A diverse class of cells that provide support, maintain homeostasis, and perform immune surveillance in the nervous system.

22
Q

What is the function of the myelin sheath?

A

It insulates axons & speeds up electrical conduction.

23
Q

What types of neuroglia are found in the Peripheral Nervous System (PNS)?

A

Schwann cells & satellite cells.

24
Q

What do astrocytes do in the Central Nervous System (CNS)?

A

They maintain the blood-brain barrier, recycle ions & neurotransmitters, & provide structural support.

25
Q

What is gliosis?

A

A response to CNS damage where astrocytes cluster to create a soft scar, limiting edema & preventing neuronal regeneration.

26
Q

Why are CNS neurons considered permanent cells?

A

They do not normally regenerate and are replaced by fibrous scar tissue when destroyed.

27
Q

What is neuroplasticity?

A

The ability of the brain to form and reorganize synaptic connections in response to learning, experience, or injury.

28
Q

What is axonotmesis?

A

A type of nerve injury where the axon is damaged but the endoneurium & surrounding myelin sheath remain largely intact, allowing potential regrowth.

29
Q

What is neurotmesis?

A

A severe type of nerve injury where the endoneurium is disrupted, making axonal regeneration unlikely.

30
Q

What can cause cell damage or death in the CNS?

A

Hypoxia, trauma, autoimmune conditions, vascular lesions, infections, and exposure to toxins.

31
Q

Why are CNS cells highly sensitive to oxygen levels?

A

They are metabolically active, using 20-30% of available oxygen/glucose at any time, making them sensitive to hypoxia (reduction of oxygen) and variations in blood sugar.

32
Q

How quickly can permanent damage occur in CNS cells with oxygen loss?

A

Permanent damage usually begins within 4-10 minutes of oxygen deprivation.

33
Q

What are some common causes of cell death in the CNS?

A

Decreased oxygen supply, genetic defects, trauma, compression, autoimmune conditions, vascular lesions, infections, & exposure to toxins.

34
Q

What are potential causes of CNS damage in utero?

A

Genetic or congenital defects, maternal illness (especially viral), drug/alcohol exposure, intrauterine infections, & thyroid dysfunctions.

35
Q

What birth-related issues can lead to CNS damage?

A

Birth canal hypoxia & direct trauma from forceps use.

36
Q

How can fractures or dislocations affect the CNS?

A

Fractures of the skull or vertebrae can cause pressure or injury to CNS structures.

37
Q

What role does compression play in CNS damage?

A

Edema, hematomas, or tumors can compress CNS cells, adversely affecting their function.

38
Q

What types of direct trauma can cause CNS injury?

A

Auto accidents, falls, sports injuries, & penetrating injuries (e.g., gunshot wounds).

39
Q

What is a coup-contrecoup injury?

A

An injury occurring at the site of trauma (“coup”) and on the opposite side of the brain (“contrecoup”).

40
Q

How do autoimmune conditions impact the CNS?

A

Conditions like multiple sclerosis can attack oligodendrocytes, while diabetes & lupus can cause various CNS dysfunctions.

41
Q

What are vascular lesions, & how do they affect the CNS?

A

Vascular lesions, such as strokes (occlusive or hemorrhagic), can create hypoxic conditions that damage CNS cells.

42
Q

What types of infections can occur in the CNS?

A

Viral, bacterial, & fungal infections; commonly named by location (e.g., encephalitis, meningitis).

43
Q

What are some common bacterial & viral infections in the CNS?

A

Pyogenic bacteria, lymphocytic viruses, & granulomatous fungi or yeast.

44
Q

What role do poisons and toxins play in CNS cell damage?

A

They impair the cell’s ability to uptake or use oxygen by damaging or blocking receptor sites on cell membranes.

45
Q

What are some examples of toxins that can damage CNS cells?

A

Drugs (prescription and recreational), chemicals, alcohol, heavy metals (e.g., mercury, lead), and carbon monoxide.