CNS-anatomical division, function, neurons,meninges, Flashcards
-Body’s neural control center
- Brain and spinal cord
- Central nervous system (CNS
-Located outside the nervous system
-Consists of nerves and sensory receptors
- Peripheral nervous system (PNS)
-carry afferent (incoming) messages to the brain or
spinal cord.
- Carries impulses from sensory receptors to the CNS
Sensory division
- Carries impulses from CNS to effectors
-carry efferent (outgoing) messages away from the
brain and spinal cord.
- Motor division
-Motor division has two divisions:
○ Somatic nervous system
○ Autonomic nervous system
-Voluntary control of skeletal muscle
Somatic nervous system
-Involuntary control of cardiac muscle, smooth muscle, and glands
Autonomic nervous system
The autonomic division has two subdivisions:
Parasympathetic
Sympathetic
-sends electrical messages to carry out functions for
vegetative activities such as digestion, defecation, and
urination.
Parasympathetic
-sends electrical messages to prepare the body for
physical activity, often referred to as fight or flight
Sympathetic .
Neurons have basically three parts:
dendrites
cell bodies
axons
-receives information
- A neuron may have anywhere from 1 to 1,000 ________
- The more _______ the neuron has, the more information it can process.
- make multiple connections and form precise pathways.
- Incoming messages travel from the dendrites toward the body
Dendrites
-are involved in protein synthesis
-nucleus and organelles for protein synthesis
-Neurotransmitters are made in the ____ of the neuron
through protein synthesis.
Body
-transmit electrical impulses.
-____ leaves the neuron body at the axon hillock, also
called the trigger zone.
-A synaptic knob at the end of each branch forms a synapse (junction)
Axon.
○ Several dendrites
○ Single axon
* Neurons whose cell bodies are located in the brain and spinal
cord are _____
multipolar neurons
- Two processes:
○ Dendrite
○ Axon - occur in the sensory portions of the eyes,
ears, and nose
Bipolar neurons
- A single process extending from the cell body
-Process divides into two branches extending in opposite
directions
-Branches function as a single axon
-sensory from the skin and organs
Unipolar neurons
There are six types of neuroglial cells that aid in neuron
function:
Ependymal
Microglia
Oligodendrocytes
Astrocytes
schwann cells
satellite cells
form myelin in the CNS.
Oligodendrocytes
cells produce cerebrospinal fluid in the
CNS.
Ependymal
form the blood-brain barrier in the CNS.
-most numerous
-maintain chemical concentration
-repair
Astrocytes
astrocytes that fill space with scar tissue
Sclerosis
-axon emerges frim cell body
-initial part of axon
Axon Hillock
-jumping conduction known as saltatory conduction
Nodes of Ranvier
seek out and fight pathogens in the CNS.
Microglia
form myelin in the PNS.
Schwann cells
control the environment for ganglia in
the PNS.
Satellite cells
- The brain and spinal cord are covered with three
membranes called
-3 fibrous membranes
meninges
3 Meninges
Dura mater
arachnoid mater
pia mater
- Tough, outermost layer
- Attached to cranial bones
- Forms protective tube in vertebral canal
Dura mater (tough mother)
contains blood vessels, adipose tissue,
and loose connective tissue
Epidural space
- Middle layer
- Thin, weblike, avascular
- Does not penetrate smaller depressions like the pia
Arachnoid mater (spider-like mother)
- Filled with cerebrospinal fluid
Subarachnoid space
- Thin, innermost layer
- Adheres to CNS structure surfaces
- Contain blood vessels to nourish brain and spinal cord
Pia mater (affectionate mother)
Produced by choroid plexuses in the ventricles
Cerebrospinal fluid
Ventricles that produces CSF
Two lateral ventricles
Third ventricle
Fourth ventricle
- Within cerebral hemispheres
Two lateral ventricles
- Midline of diencephalon
Third ventricle
- Midline of brain stem
- Continuous with central canal of spinal cord
Fourth ventricle
Flow of cerebrospinal fluid
-Lateral ventricles to third ventricle to fourth ventricle
to central canal or subarachnoid space
- From subarachnoid space upwards around the brain or
down posterior side of spinal cord, then up anterior side
Cerebrospinal fluid is reabsorbed in________ within
dura mater.
Dural sinus
Functions of CSF
-provides bouyancy
-provides protection
-facilitates chemical stability
-provides nutrients
