Define the Nervous system
A network of trillions of cells organized to form the body's rapid control system.
Define the Central Nervous System
Consists of the brain and spinal column
Define the Peripheral Nervous System
"Everything Else" ie peripheral nerves
List the four main functions of the nervous system
- 1. Detect and Transmit
- 2. Analyze information
- 3. make a decision (may be conscious or unconscious)
- 4. Execute a response
Describe the composition of the Reflex Pathway
- 1. Afferent (sensory) pathway- PNS-CNS
- 2. Efferent (motor) pathway- CNS to organs
- 3. Interneuronal pathways- Within the CNS only
Define cranial nerves
12 pairs of peripheral nerves originating primarily from the brain
Define spinal nerves
messages to and from the brain via the spinal cord
Sensory. Afferent. Input. Dorsal.
Motor. Output. Ventral. Efferent
List the four main regions of the spinal cord
Cervical, Thoracic, Lumbar, Sacral
Define Visceral Sensory
Information coming from the internal organs
Define autonomic efferent
Information going to the internal organs
Define Somatic Sensory
Information coming from touch, pressure, temperature etc.
Define Somatic motor
Information going to the skeletal muscle
What is a Dermatome?
The area of skin innervated by sensory axons of nerves
What is a Myotome?
A collection of muscle fibers innervated by the motor axons of each nerve
Starting from top to bottom, what is the arrangement of sensory, motor, and autonomic nuclei within the spinal cord?
- somatic sensory
- visceral sensory
- autonomic efferent
- somatic motor
What is the purpose of this arrangement?
This separation prevents cross-talk within the spinal cord
What are ascending tracts?
Sensory information form the spinal cord to the brain
What are descending tracts?
Information from the brain to the spinal cord
What is the purpose of ascending and descending tracts?
Linking the peripheral nerves to the brain
Explain how one side of the brain controls the opposite side of the body
Pathways form the PNS crossover to the opposite side of the CNS
List the four lobes of the Cerebral Cortex
Name the 2 classes of cholinergic receptors
What do Nicotinic receptors do?
Open Na+/K+ channels (ionotropic)
What do muscarinic receptors do?
G-protein coupled receptors (metabotropic)
Name the five common adrenergic receptor sub-types
- alpha 1
- alpha 2
- beta 1
- beta 2
- beta 3
Where are the alpha 1 receptors found?
most vascular smooth muscle/pupils (NE>E)
Where are the alpha 2 receptors found?
CNS, platelets, autoreceptors, some vascular smooth muscle and adipose tissue (NE>E)
Where are the beta 1 receptors found?
CNS, cardiac muscle and kidneys (NE=E)
Where are the beta 2 receptors found?
some blood vessels, respiratory tract, uterus (E>NE)
Where are the beta 3 receptors found?
adipose tissue (NE=E)
Sympathetic nervous system?
Fight or flight
Parasympathetic nervous system?
Rest and digest
Explain dual innervation
an area can be stimulated by SNS or PSNS
What is the structure of the sympathetic nervous system?
- origin in the thoracic/ lumbar
- Ganglia found close to the spinal cord (short pre, long post)
What is the structure of the parasympathetic nervous system?
- Origin in the brain and the spinal cord
- Ganglia lie close to target organ (long pre, short post)
List the neurotransmitters released in the pre- and post- ganglionic cells along with their receptors of the sympathetic nervous system
- pre- Ach-Cholinergic nicotinic receptors
- post- NE-adrenergic receptors
List the neurotransmitters released in the pre- and post- ganglionic cells along with their receptors of the parasympathetic nervous system
- Pre- Ach-Cholinergic nicotinic receptors
- Post- Ach- cholinergic muscarinic receptors
Define/describe the neruoeffector junction
synapse between an efferent neuron and its effector(target) organ
Describe the structure of the somatic motor division
A single neuron starts in the ventral horn of the spinal cord and ends in target tissue (skeletal muscle)
Describe the neuromuscular junction
Between a motor neuron and skeletal muscle
Describe the motor end plate
specialized region of a skeletal muscle fiber's plasma membrane containing Ach nicotinic receptors
Define a motor unit
Group of muscle fibers and the single motor neuron that controls them