11. The Nervous System Flashcards
Cranial Nerves pairs
12 pairs
Spinal Nerves pairs
31 pairs o Cervical Nerves – 8 pairs o Thoracic Nerves – 12 pairs o Lumbar Nerves - 5 pairs o Sacral Nerves – 5 pairs o Coccygeal Nerves – 1 pair
is a nerve cell that conducts impulses towards or into the spinal cord, or up the spinal cord to the brain
Sensory neuron – or an afferent neuron
is a nerve cell that carries impulses from the brain down to the spinal cord, or from the cord to muscles or secreting glands, or directly from the brain to muscle or to a gland
Motor neuron – or an efferent neuron
is the point of contact of the axon of one nerve with the Dendron of another neuron
Synapse
is a structure at the free end of an axon or Dendron designed to pass on or pick up impulses or sensations
Endorgan
is an endorgan at the outer end of a Dendron of a sensory neuron that picks up sensations
Receptor
is an endorgan at the distal end of an axon of a motor neuron. It may be a plate on a muscle fiber carrying impulses for contraction, or minute delicate branching fibers about the secreting cells of gland that stimulate secretion
Effector
is a group of nerve cell bodies of the spinal cord or brain
Ganglion
is a group of cell bodies within the brain and spinal cord
Nucleus
is a group of nerve cell bodies concerned with some specific function
Center
consists of nerve, fibers, axons and dendrites
White matter
and are white in color
is made up of the nerve cell bodies and some processes.
Gray matter
It appears darker than the white matter
is a network of cell processes
Plexus
are large columns of nerve fibers that pass up and down the spinal cord or brain
Funiculi
are bundles of nerve fibers, and parts of funiculi in close contact with each other that pass up or down the spinal cord
Tracts
is that property of nerves that renders them responsive to stimuli such as heat, cold, etc.
Irritability
is the ability to convey impulses, generated by stimuli, along the neurons. The impulse is carried in one direction – from dendrites to cell body – to axon – to synapse
Conductivity
function in communication and control
Nervous System
The 2 divisions of the nervous system
Central nervous system and Peripheral nervous system
The brain is further divided into the:
forebrain, midbrain and hindbrain
consists of the cerebrum and diencephalon or interbrain, or in between brain
Forebrain
includes two cerebral peduncles, and four small bodies, the corpora quadrigemina or colliculi
Midbrain
has a pons, medulla oblongata and cerebellum
Hindbrain
It occupies the entire cerebral cranium
brain
The ventricles of the brain are four cavities that lie within it:
the right lateral ventricle, and the left lateral ventricle, the third ventricle, and the fourth ventricle
are networks of veins in the wall of each ventricle. Special cells in these areas secrete the CSF into the ventricles
Choroid Plexuses
about 40 to 45 cm (16 to 18 inches) in length lies within the vertebral canal, which is formed by the vertebral foramina of the vertebrae and the ligaments between their arches
spinal cord
Four large bundles (funiculi)
spinal cord
are the coverings of the brain and spinal cord
meninges
a small cavity – a belly
ventriculus
spinal marrow
medulla spinalis
They have their centers in midbrain, pons, and medulla
Cranial Nerves
31 pairs connected to the spinal cord
Spinal Nerves
There are 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal, right and left
Spinal Nerves
Plexus of nerves
- Cervical Plexus
- Brachial Plexus
- Thoracic Nerves
- Lumbar Plexus
- Sacral Plexus
self + nomos = a law –a law unto itself or self-regulating
(G) autos
is classified as a part of the peripheral nervous system
autonomic nervous system
Its controlling centers however lie within the central nervous system, in the midbrain, pons, medulla and spinal cord
autonomic nervous system
restricts it to motor or efferent nerves
autonomic
autonomic nervous system
- Contraction and dilation of all organs with visceral (involuntary) muscles in their walls
- The rate of the heart beat
- The activity of many secreting exocrine glands
autonomic nervous system 2 divisions
- Sympathetic nervous system
* Parasympathetic nervous system
is the system that is active in emergencies
Sympathetic part
The heart rate is increased, the BP becomes elevated, the bronchi dilated, and the digestive processes become arrested, etc.
Sympathetic part
is concerned with the normal body functions, usually with reactions opposite to those of the sympathetic part
Parasympathetic part
The heart is slowed, blood vessels dilate, blood pressure falls, and the digestive processes and glandular secretions are stimulated
Parasympathetic part
In Sympathetic, pupil
dilates
In Sympathetic, bronchi
dilates
In Sympathetic, heart
speeds up
In Sympathetic, stomach, intestine, GB and bile ducts
decrease peristalsis and contraction
In Sympathetic, sweat
sweating
In Sympathetic, salivary
decreases secretions
In Sympathetic, gastric
decreases secretions
In Sympathetic, intestinal arteries of skin and viscera
constricts
In Parasympathetic, pupil
constricts
In Parasympathetic, bronchi
constricts
In Parasympathetic, heart
slows down
In Parasympathetic, stomach, intestine, GB and Bile ducts
increases
In Parasympathetic, sweat
nil
In Parasympathetic, salivary
increases secretions
In Parasympathetic, gastric
increases secretions
In Parasympathetic, intestinal arteries of skin and viscera
no effect
Protection of the Brain and Spinal Cord
- Skull
- Vertebral Column
- Meninges and CSF
absence of a brain
Anencephalus
a small head
Microcephalus
a large head due to a block in the apertures in the roof of the fourth ventricle resulting in the accumulation of CSF in the ventricles
Hydrocephalus
a swelling in the midline of the subject’s back due to a hernia of the spinal cord and meninges through a defect in a vertebral arch
Meningocele
an inflammation of the brain
Encephalitis
an inflammation of the meninges, the membranes covering the brain and spinal cord
Meningitis
infantile paralysis –an inflammation of the motor cell bodies in some part of the spinal cord, caused by a virus
Poliomyelitis
is a test that shows images of your heart
Ventriculogram
any of various techniques for recording the structure or electrical activity of the brain
Encephalography
is used to look at the blood vessels of the brain, head, or neck
Cerebral Arteriography
is a diagnostic imaging test generally done by a radiologist. It uses a contrast dye and X-rays or computed tomography (CT) to look for problems in the spinal canal
Myelography
