principles of nervous system 1

Question 1

What is a neuron?

Answer 1

functional unit of the nervous system

Question 2

What are neuroglia?

Answer 2

support neurons

Question 3

What are the 5 parts of a neuron?

Answer 3

• soma/cell body
• dendrites
• axon hillock
• axon/nerve fibre
• axon terminals

Question 4

Describe the soma/cell body of a neuron

Answer 4

• contains nucleus
• synthesis of proteins (lots of ER)
• cellular metabolism (lots of mitochondria)

Question 5

Describe the dendrites of a neuron

Answer 5

• receives inputs
• convey info towards soma
• large SA (spines) for synapse formation

Question 6

Describe the axon hillock of a neuron

Answer 6

• origin of the axon
• very excitable

Question 7

Describe the axon/nerve fibre of a neuron

Answer 7

• transmits action potential
• usually only one (althoug may branch)

Question 8

Describe the axon terminals of a neuron

Answer 8

• synpase on other neurons/effector organs
• may form specialised sensory endings

Question 9

What is a unipolar neuron?

Answer 9

• one axon only
• we have pseudounipolar

Question 10

Give examples of pseudounipolar neurons?

Answer 10

• primary sensor neurons

Question 11

Where are the cell bodies of our pseudounipolar neurons found?

Answer 11

dorsal root ganglia

Question 12

What is a bipolar neuron?

Answer 12

one axon and one dendrite

Question 13

Give examples of bipolar neurons

Answer 13

• specialised sensory neurons
• found in retina, olfactory epithelia

Question 14

What are multipolar neurons?

Answer 14

one axon and multiple dendrites

Question 15

Give examples of multipolar neurons

Answer 15

• majority of neurons in brain
• motor neurons
• autonomic ganglia

Question 16

How big usually are myelinated axons?

Answer 16

1-10 micrometers diameter

Question 17

How big usually are unmyelinated axons?

Answer 17

under 1 micrometer diameter

Question 18

What are 3 types of neuroglia?

Answer 18

• astrocytes
• oligodendrocyte
• microglia

Question 19

What are the functions of astrocytes?

Answer 19

• structural support
• scaffold for neurons during development
• supply nutrients
• maintain ionic gradients
• neurotransmitter uptake
• repair of nervous system
• form barrier around vessels

Question 20

What do oligodendrocytes do?

Answer 20

myelinates axons

Question 21

What do microglia do?

Answer 21

act as immune cells
- secrete cytokines
- phagocytic
- cytotoxic
promote repair

Question 22

What are the neuroglia of the peripheral nervous system (PNS)

Answer 22

schwann cells

Question 23

What are the functions of schwann cells?

Answer 23

• myelinate axons
• secrete cytokines, phagoytic
• regeneration (provide substrate for axon to grow along)

Question 24

What constitutes the central nervous system?

Answer 24

• brain
• spinal cord

Question 25

What constitutes the peripheral nervous sytem?

Answer 25

communication between CNS and periphery

Question 26

What is the most superior part of the brain called?

Answer 26

dorsal surface

Question 27

What is the brain divided into?

Answer 27

• forebrain
• midbrain
• hindbrain

Question 28

What is grey matter in the brain?

Answer 28

• neuronal cell bodies
• synapses
• dendrites

Question 29

What is white matter in the brain?

Answer 29

myelinated axons

Question 30

What makes up the forebrain?

Answer 30

• cerebral hemispheres
• thalamus
• hypothalamus

Question 31

What makes up the hindbrain?

Answer 31

• pons
• medulla
• cerebellum

Question 32

Describe the cerebral hemispheres

Answer 32

• outer grey matter is cerebral cortex
• 10-20 billion neurons
• 2.5mm thick
• divided into lobes

Question 33

What are the functions of the cerebral hemispheres?

Answer 33

• processing motor and sensory information (20%)
• cognition (80%)

Question 34

Describe the thalamus

Answer 34

• relay centre of brain
• paired structure
• centrally located
• sensory info passes via thalamus before reaching cortex

Question 35

Describe the hypothalamus

Answer 35

• important in homeostasis
• sits below thalamus
• controls autonomic and endocrine nervous systems

Question 36

What is the brainstem formed by?

Answer 36

midbrain and hindbrain

Question 37

What does the brainstem do?

Answer 37

• connects cortex to spinal cord
• controls respiration and cardiovascular systems

Question 38

What does the cerebellum do?

Answer 38

coordinate muscular activity

Question 39

Where does the spinal cord start and go to?

Answer 39

from atlas (C1) to first/second lumbar vertebra (L1-L2)

Question 40

Where does the spinal cord sit?

Answer 40

within vertebral canal

Question 41

What are the functions of the spinal cord?

Answer 41

• conveys info
• involved in reflexes

Question 42

What are the segments of the spinal cord called from top to bottom?

Answer 42

• cervical
• thoracic
• lumbar
• sacral

Question 43

Describe the spinal cords anatomy

Answer 43

• inner core of grey matter
• outer white matter
• efferent axons exit ventrally
• afferent axons enter dorsally
  (via peripheral nerves)

Question 44

How are axons organised?

Answer 44

into fascicles

Question 45

What are the layers of axons from outside to in?

Answer 45

• epineurium
• perineurium
• endoneurium

Question 46

What are the two components of the peripheral nervous system?

Answer 46

• somatic (voluntary)
• autonomic (involuntary)

Question 47

What does the somatic component of the nervous system supply?

Answer 47

• skeletal muscles
• sensory from skin, muscles and joints

Question 48

What does the autonomic component of the nervous system supply?

Answer 48

• viscera
• smooth muscle
• glands and vessels

Question 49

Where do all peripheral nerves arise from?

Answer 49

• brain or brainstem as cranial nerves
• spinal cord as spinal nerves

Question 50

What do spinal nerves provide?

Answer 50

• motor supply
• sensory (somatic) supply
• sympathetic (autonomic) supply