Neurophysiology

Question 1

Name the nervous systems

Answer 1

1. Central nervous system and peripheral nervous system
2. Somatic nervous system and autonomic nervous system
3. Sympathetic nervous system and parasympathetic nervous system

Question 2

What are the specialized cells of the nervous system and what do they do?

Answer 2

Neurons
- rapid transmissions of action potentials
- made up of dendrites, cell body, axon, synaptic terminals
Neuroglial / glial cells:
- form a syncytium (unified cytoplasm of each glial cell)
- cells act as one
- gap junctions provide cell communication

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Question 3

What are the types of glial cells and what nervous system do the belong to?

Answer 3

CNS: microglia, astrocyte, oligodendrocyte
PNS: Satellite cell. Schwann cell

Question 4

Which part of a neuron conducts action potentials from the cell body to the intended target?

Answer 4

Axon

Question 5

What is the purpose of myelin sheaths?

Answer 5

To insulate axons and increase conduction velocity of action potentials

Question 6

Which division of the autonomic nervous system generally has short preganglionic neurons and long postganglionic neurons?

Answer 6

Both parasympathetic and sympathetic systems have the same neuron length

Question 7

What is the purpose of the autonomic nervous sytem?

Answer 7

Control involuntary functions of organs and tissues

Question 8

The pineal gland is located in the:

Answer 8

Epithalamus

Question 9

Explain dendrites, axon and the cell body

Answer 9

Dendrites:
- PNS function: receive info. and transfer it within neuron
- CNS function: send signals back and forth with other neurons
Cell body: Has nucleus and organelles
Axon: transmit outgoing electrical signal
- convey chemical and electrical signals

Question 10

What are the nodes of Ranvier?

Answer 10

enable action potentials to jump between nodes which increase saltation

Question 11

What does the cell body propagate?

Answer 11

Propagates action potential when threshold is reached thanks to the Ca2+ stores

Question 12

What is axonal transport?

Answer 12

When proteins moved in vesicles down axon. These protein are synthesized in rER in cell body

Question 13

Explain action potentials

Answer 13

Will only be generated once threshold voltage is reached.
Depolarize the RMP of post synaptic membrane which depolarizes the membrane to -50mV

Question 14

Explain the refractory period and its two types

Answer 14

Absolute refractory period: voltage gated Na channels are inactive
Relative refractory period: Na channels are close and active and replenishing of Ca2+ storage

Question 15

What is compound action potential?

Answer 15

Peripheral nerves are generally bundles of nerve axons
Sum of all electrical activity happening in each axons in nerve bundle

Question 16

What does the central nervous system consist of?

Answer 16

Brain and spinal cord
Afferent sensory information (info. from senses) and providing efferent response (signal/response command)

Question 17

What is the brain composed of?

Answer 17

Brainstem, cerebellum, diencephalon and cerebrum

Question 18

Describe the parts of the brainstem

Answer 18

Medulla oblongata: runs continuous with spinal cord
- motor and sensory nuclei for throat, mouth, neck (sensory nuclei: respiratory and cardiovascular control)
The pons: continuous with medulla and contains nuclei responsible for respiratory system
Midbrain: continuous with pons below and diencephalon above

Question 19

Explain the cerebellum

Answer 19

Attached to brainstem and concerned with rate, range and direction of movement

Question 20

What is the diencephalon comprised of?

Answer 20

Thalamus:
-relay afferent info. to ipsilateral cerebral cortex
- sleep and wakefulness
Subthalamus
Hypothalamus: regulates autonomic functions
- blood pressure
- heart rate
- body temp.
- control hormone from hypophysis (pituitary)
- regulate intake of food

Question 21

What is the cerebrum?

Answer 21

Contains specialized areas: motor cortex, somatosensory cortex, visual cortex, auditory cortex

Question 22

What is the spinal cord composed of?

Answer 22

Dorsal and ventral roots protruding from both sides
Dorsal roots carry afferent signals; ventral roots carry efferent signals

Question 23

What are the most important cranial nerves?

Answer 23

IX: glossopharyngeal
X: Vagus

Question 24

Explain the peripheral nervous system

Answer 24

Sensory pathways start with receptors.
Transduction process leads to an electrical response in the primary afferent called receptor potential

Question 25

What is the receptor potential?

Answer 25

Triggers action potential: contain information about sensory stimulus conveyed to the CNS via primary afferent

Question 26

Explain the somatic nervous system

Answer 26

Contains all peripheral pathways which control skeletal muscle and responsible for communicating with the environment

Question 27

What are types of fibers and their explanations?

Answer 27

Fibers type a: motor neuron - large myelinated sheath
Fiber type b: small, no myelination - pain

Question 28

What is the autonomic nervous system?

Answer 28

Involuntary control of vast majority of organs with exception of motor control of skeletal muscle

Question 29

What are the two sub types to the autonomic nervous system?

Answer 29

Sympathetic nervous system
Parasympathetic nervous system

Question 30

Which are the main characteristics of sympathetic and parasympathetic nervous systems?

Answer 30

Sympathetic:
- generally has short preganglionic neurons and long postganglionic neurons
Parasympathetic:
- possess long preganglionic neurons and short postganglionic neurons

Question 31

Briefly explain the enteric nervous system

Answer 31

Consists of autonomic neurons of the gi ttact from oesophagus to anus
Cells not influenced by CNS

Question 32

What is proprioception?

Answer 32

Experience and understand our position and the position of any part of our body in a 3D space, movement and force.

Question 33

Where are the most relevant proprioceptor found?

Answer 33

Capsule of joints, muscles and tendons
- golgi tendon organ
- muscle spindle
- joint receptor