intro to neurophysiology

Question 1

Which divisions act as a medium for the input to the CNS, and conduct impulses from the periphery to the brain and spinal cord?

Answer 1

Afferent division

Question 2

How many sections is the efferent division split into, and what are the names?

Answer 2

2
Somatic Nervous system
Autonomic Nervous Sytem

Question 3

What is the somatic nervous system composed of?

Answer 3

Motor neurons conduct the impulses to skeletal muscles.

Question 4

What is the autonomic nervous system composed of?

Answer 4

Sympathetic and Parasympathetic:
controls Smooth and Cardiac muscles
and Exocrine and some endocrine glands

Enteric nervous system:
Digestive organs only
It can receive stimuli from both the efferent division and the digestive tract.

Question 5

Which cells make up the nervous system? How do they differ?

Answer 5

Neurons:
>100 bil
basic structured
Mostly myelinated
Can generate an electrical potential
damage causes neurological disorders

Glial cells
2-10 times more
Dendrites and axons are absent
Not electrically excitable

both arise from the same precursors differ in function.

Question 6

Describe a neuron’s structure and how each compartment relates to the following processes: input, integrative, conductive, and output.

Answer 6

input:
Dendrites- cytoplasmic extensions of the cell body.
The cell body comprises a nucleus, nissl bodies (RER and free ribosomes), mitochondria, neurofilaments, and Golgi bodies.
integrative:
Axon hillock- the region between the axon and cell body.
Conductive:
Axon- surrounded by axolemma and conducts the electrical potential to the telodendria.
Output:
It occurs at the terminal branches where a synapse is formed with another neuron or target organ. Hence presynaptic terminal and postsynaptic neuron.

Question 7

What are the characteristics of neurons?

Answer 7

High metabolic rate- abundant mitochondria
Aerobic respiration- an abundant supply of glucose and oxygen
Longevity- formed during fetal development and remains functional.
Non-mitotic- lost in fetal development

Question 8

Describe the structural classifications of neurons.

Answer 8

Unipolar
single primary process
carries somatosensory information- sense

Bipolar
Two distinct processes
retina and olfactory system

Multipolar
a single axon, multiple dendrites
vertebrates

Question 9

Describe the functional classification of neurons.

Answer 9

Sensory neuron:
afferent
cell body found in the posterior root ganglion

interneuron:
in the spinal cord
conducts from sensory to motor

Motor neuron:
Efferent

Question 10

Name the glial cells.

Answer 10

Central:
Astrocytes
Ependymal cells
Microglia
Oligodendrocytes

Peripheral:
Satellite cells
Neurolemmocytes (Schwann cells)

Question 11

Describe the Astrocytes.

Answer 11

Star like
In contact with neurons and capillaries
BBB
Regulate tissue fluid composition/ ECF
Structural support
Replaces damaged neurons
Regulate neural development

Question 12

Describe Ependymal cells

Answer 12

Simple cuboidal
cilia on apical surfaces
line cavities in brain (ventricles) and spinal cord (central canal)
Assist in conduction and circulation of CSF

Question 13

Describe the microglia cells.

Answer 13

Small
Monocyte lineage
least common
immune functions
clear cellular debris and dead neurons
influence synaptic transmissions and synaptogenesis.

Question 14

Describe Oligodendrocytes.

Answer 14

Round cells
Slender cytoplasmic extensions- wraps around CNS axons
Myelinates and Insulate axons
fastens nerve impulse conduction

Question 15

Describe satellite cells

Answer 15

Flattened cells
clustered around neuronal cell bodies in the ganglion
Protect and regulate nutrients for cell bodies

Question 16

Describe neurolemmocytes.

Answer 16

Myelinates axons
1 Schwann cell= one segment of the myelin sheath
Gaps- Nodes of Ranvier

Question 17

Describe periphery myelination.

Answer 17

Schwann cell cytoplasm surrounds the axon.
Its membrane then enwraps the axon.
The membrane then becomes compacted.

Question 18

Describe the relationship between the thickness of myelin and the speed of the conduction.

Answer 18

The thicker the myelin the faster the speed.

Question 19

What are the functions of the gyrus and sulcus?

Answer 19

It creates folds and ridges in the brain separating it into different compartments or regions.
Allows the brain to fit into the cranium whilst providing a large surface area.

Question 20

Describe the functional areas found in the frontal lobe of the brain.

Answer 20

Primary motor cortex (in the precentral gyrus just before the central sulcus)- voluntary movement

Premotor cortex- coordination of complex movements.

Frontal eye field
Motor speech area (Broca’s area)- Speech formation

Prefrontal association cortex- planning of voluntary activity, decision-making, and personality traits. Working memory?

Question 21

Describe the functional areas of the parietal lobe.

Answer 21

Primary somatosensory cortex (postcentral gyrus)- sensation and proprioception

Somatosensory association area- spatial perception

Wernicke’s area- speech and writing understanding.

Gnostic area- integration of all sensory input, important in language

Question 22

Describe the functional region in the Occipital lobe.

Answer 22

Primary visual cortex
Visual association area

Question 23

Describe the functional regions of the temporal lobes.

Answer 23

Primary auditory cortex
auditory association area
Limbic association cortex- motivation and emotion and memory.

Question 24

Describe the functional regions of the insula.

Answer 24

Primary Gustatory cortex- taste

Question 25

Describe the structures found in the Diencephalon.

Answer 25

Thalamus- centers all information except olfactory and relays this information to different parts of the cerebrum
Hypothalamus
Epithalamus-Pineal gland- melatonin- sleep.

Question 26

What are the names of the autonomic respiratory centers in the Pons? Explain their functions.

Answer 26

Pneumotaxic and Apneustic
Sets pace and rate
initiation of respiration

Question 27

What is the function of the medulla?

Answer 27

Cardiac center and vasomotion nuclei.
sets heart rate and controls the total peripheral resistance.

Question 28

Describe the cranial meninges.

Answer 28

Pia Mater:
innermost
thin. delicate areolar CT
Highly vascularize
tightly adheres to the brain

Arachnoid mater:
delicate web collagen and elastic fibers
arachnoid trabecular

Dura mater:
An external tough, dense, and irregular connective tissue
Fibrous layers: meningeal(deep) and periosteal

Question 29

Explain how the ventricles protect the brain.

Answer 29

It contains the choroid plexus, a highly vascularised area in which the cavities are lined by ependymal cells.
The blood is used to produce CSF, which creates buoyancy and also regulates the environment of the neurons.

Question 30

Describe the flow of CSF.

Answer 30

Lateral ventricles- 3rd ventricle- 4th ventricle into meninges and suprascapular spaces and then empties into the superior sagittal sinus.