Nervous System

What is the function of the nervous system?

Detects and responds to changes inside and outside the body

What system works together with the nervous system?

Endocrine system

What are the three main components of the nervous system?

Brain

Spinal cord

Peripheral nerves

What are the two parts of the nervous system?

Central nervous system

Peripheral nervous system

What are the components of the central nervous system?

Brain and spinal cord

What is the component of the peripheral nervous system?

Peripheral nerves

What are the two types of nervous tissue?

Neurones

Neuroglia

What are the five components of the neurones?

Cell body

Axon

Dendrites

Axon terminal

Terminal boutons

What is the function of neurones?

Generate and transmit electrical impulses called action potentials

What are the two types of stimuli that initiate action potentials?

External and internal

Where does electrical transmission of nerve signals occur?

Travelling down the nerve axon

Where does chemical transmission of nerve signals occur?

Between nerve cells across synapses

What structure makes up the grey matter of the nervous system and where are they found?

Cell bodies

Periphery of brain and in centre of spinal cord

What are groups of cell bodies called?

Nuclei in the CNS

Ganglia in the PNS

What are the two different names for groups of axons and where are they found?

Tracts at the periphery of the spinal cord

Nerve fibres outside the CNS

What are dendrites?

Numerous, short, branching extensions of the cell body that recieve and transmit action potentials

What is the tapered area of the cell body called?

Axon hillick

What is the outer membrane of the axon called?

Axolemma

What are the two types of neurones?

Myelinated

Unmyelinated

What are unique characteristics of myelinated neurones?

Myelinated sheath made up of layers of Schwann cells wrapped around the axon

What is myelin?

Fatty substance between layers of Schwann cell plasma membrane

What is the neurilemma?

Outermost layer of Schwann cell plasma membrane

What are nodes of Ranvier?

Tiny areas of exposed axolemma

What are the three structural classifications of neurones?

Multipolar

Bipolar

Unipolar

How do you identify a multipolar neurone and where are they found?

Several dendrites and one axon

Brain and spinal cord

How do you identify bipolar neurones and where are they found?

One main dendrites and one axon

Found in retina, inner ear and olfactory area

How do you identify a unipolar neurone?

Dendrites and axon fused together to from a continuous process

What is a synapse?

The point an action potential passes from one neurone to

What is the synaptic cleft?

Space between the terminal boutons and dendrites

What do vesicle in the synaptic knobs contain?

Neurotransmitter

What are nerves?

Collection of neurones bound together by connective tissue

What are the three coverings of protective connective tissue in neurone bundles?

Endoneurium

Perineurium

Epineurium

What are the three functional classifications of neurones?

Sensory

Motor

Interneurones

What is the function of sensory nerves?

Carry information from the body to the spinal cord

What is the function of motor neurones?

Convey action potentials to effectors through cranial or spinal nerves

What are the two types of motor neurones?

Somatic nerves

Autonomic nerves

What is the function of somatic nerves?

Voluntary and reflex of skeletal muscle contraction

What are the two types of autonomic nerves and what are their functions?

Sympathetic and parasympathetic

Involuntary functions

What is the function of inter neurons?

Process sensory information and activate motor neurones

What are tracts?

Seperate groups of sensory and motor neurones in the spinal cord

What are mixed nerves?

Sensory and motor nerves enclosed in the same connective tissue sheath outside the spinal cord

What are neuroglia?

Non excitable glial cells supporting the neurones of the CNS

What are the four types of neuroglia?

Astrocytes

Oligodendrocytes

Ependymal cells

Microglia

What is the function of astrocytes?

Form a sleeve around blood vessels, contributing to the blood brain barrier

What is the function of oligodendrocytes and where are they found?

Form and maintain myelin in the CNS

Multiply around degenerating neurones

Cluster round grey matter and along myelinated nerve fibres

What is the function of ependymal cells and where are they found?

Assist the flow of CSF through cavities in the brain

Ciliated cells in epithelial lining of ventricles and central canal

What is the origin of microglia cells?

Derived from monocytes migrating from the blood into the nervous system

Found in the brain

What is the function of microglia cells?

Enlarge and become phagocytise when inflammation and cell damage migrate to the brain

What are the meninges and where are they found?

Three layers of protective tissue

between the skull and brain

between the vertebral foramina and spinal cord

What are the three meninges?

Dura matter

Arachnoid matter

Pita matter

What are the two spaces associated with the meninges?

Subdural space

Subarachnoid space

What is the subdural space?

Potential space between dural and arachnoid maters

Contains small amount of serous fluid

What is the subarachnoid space?

Potential space between the arachnoid and pia maters

Contains cerebrospinal fluid

What is the arachnoid mater?

Fibrous membrane between dura mater and pia mater

Continues down the spinal cord and merges with the dura at the second sacral vertebra

What is the pia mater?

Connective tissue layer with many blood vessels contouring to the brain

Continues down, surrounding the spinal cord and fusing with the periosteum of the coccyx

What is the dura mater?

Loose covering around the spinal cord continuing from the brains inner dura layer

starting at the foramen magnum

extending into the second sacral vertebrae

What are the four ventricles of the brain?

Right and left lateral ventricle

Third ventricle

Fourth ventricle

Where is cerebrospinal fluid made?

In brain ventricles by choroid plexuses

What are choroid plexuses?

Areas full of blood vessels lined with ependymal cells

What is the pathway of cerebrospinal fluid flow?

Through the brain and spinal cord

Absorbed back into bloodstream through arachnoid villa

Arachnoid villa stick out into venous sinuses

What factor determines CSF flow into the blood?

Pressure differences

What are the six main components of the brain?

Cerebrum

Thalamus

Hypothalamus

Midbrain

Pons

Medulla oblongata

What is the location of the cerebrum?

Front and middle part of the skull

What is the structure of the cerebrum?

Split into right and left hemispheres each with a lateral vesicle

What structure separates the left and right hemispheres of the cerebrum?

Longitudinal fissure

What structure connects the left and right hemispheres of of fhe cerebrum?

Corpus callosum (bundle of nerves)

What is the cerebral cortex?

Outer layer of the cerebrum

What are gyri?

Folds in the surface of the cerebrum

What are sulci?

Grooves in the surface of the cerebrum

What are the four lobes of each cerebral hemisphere?

Frontal

Parietal

Temporal

Occipital

What are the three sulci of the cerebral hemispheres?

Central sulci

Lateral sulci

Parieto occipital sulci

Where is the thalamus found?

One on each side of the third ventricle

What is the function of the thalamus?

Recieves signals from skin, organs and sense organs to detect basic sensations

Relay station

Where is the hypothalamus found?

Below and in front of the thalamus

Above the pituitary gland

What links the hypothalamus to the posterior lobe of the pituitary gland?

Nerve fibres

What links the hypothalamus to the anterior lobe of the pituitary gland?

Complex blood vessel system

Where are the pons located?

In front of the cerebellum

Below the midbrain

Above the medulla oblongata

What is the function of the pons?

Connects cerebellum and links brain to spinal cord

Helps process signals for some cranial nerves

Where is the medulla oblongata located?

Most inferior region of brain stem

Above the foramen magnum

Continuous with spinal cord

Where is the spinal cord located?

Vertebral canal

Extends from upper border of atlas

Terminates at lower border of first lumbar vertebra

How many cervical nerves are there?

8

How many thoracic nerves are there?

12

How many lumbar nerves are there?

5

How many sacral nerves are there?

5

How many coccygeal nerves are there?

1