Senses Environment – receives information from both outside and inside the body

Processes the information it receiveS

Respond to information – sends out

orders

• Neurons – the cells that are responsible for transmitting message
• Neuroglial cells – cells that support the neurons

NERVOUS TISSUE OUTSIDE BRAIN AND SPINAL CORD

SENSE ORGANS

AFFERENT

(SENSORY NEURONS)

NEURONS CARRY MESSAGES TO CNS

LOCATION : DORSAL ROOT GANGLION

(MOTOR NEURON)

NEURON CARRY MESSAGES FROM CNS

 LOCATED : GRAY MATTER OF SPINAL CORD

LOCATED : BETWEEN SENSORY AND MOTOR NEURONS WITHIN CNS

INTEGRATE AND INTERPRET SENSORY SIGNALS

MULTIPLE SCLEROSIS CAUSE AND EFFECT

 Caused by the destruction of the myelin sheath that surrounds axons found in the CNS

 Can result in paralysis and loss of sensation, including loss of vision

AXON 

BLODD VESSELS

 CONNECTIVE TISSUE

WITH ACTION POTENTIAL, involves sodium ions (Na+) and potassium ions (K+) that cross the cell membrane through the ion channels

EACH ION CHANNEL IS ALLOWED TO PASS ONLY CERTAIN IONS

 3 Na+ ions out for every 2 K+ ions into the cell

REQUIRES ATP

SODIUM IONS ENTER THE AXON

POSITIVE INSIDE

POTASSIUM IONS LEAVES AXON

NEGATIVE INSIDE

1. Presynaptic neuron is the transmitting neuron

2. postsynaptic neuron is the receiving neuron or the muscle

3. And the gap in between them = synaptic cleft

1. action potential gets to the end of the presynaptic axon THEN 
2. triggers Ca2+ to enter the presynaptic axon terminal then Then
3.  Ca2+ triggers synaptic vesicles to merge with the neural membrane
4. synaptic vesicle release neurotransmitters to syn. cleft
5. neurotransmitter travel to postsynatic neuron
6. neurotransmitted binds to receptor on PN
7. ligand gates allows Na to enter PN then triggers action potential in PN
8. when NT released need to be destroyed . 

Acts in both the PNS and the CNS as a neurotransmitter

 Causes voluntary muscles to contract 

Acetylcholinesterase