Neuron & Reflex Arc, Study notes of Neurobiology

Download Neuron & Reflex Arc and more Study notes Neurobiology in PDF only on Docsity!

• April 3rd

What were neurons again?

The Neuron

dendrites : short branches that conduct impulse towards cell body cell body/soma : contains the nucleus and other organelles axon: long projection that conduct impulse away from cell body axoplasm : electrically-conductive cytoplasm within the axon that transmits impulses axomembrane : plasma membrane of neurons that is responsible for maintaining the axon's membrane potential

The Neuron

Neuron axons are packed together into nerves nerves can contain a mixture of neurons (sensory & motor) that send info in both directions to different places not all neurons form nerves ganglion: neuron cell body cluster in the PNS

The Neuron - Myelin Sheath

Functions:

a) insulates the

neurons from each

other as they are

tightly packed

together within a

nerve

b) accelerates

impulse transmission

Myelin Sheath Degeneration

The Neuron - Axon

Node of Ranvier : points between Schwann Cells Saltatory transmission : the "jumping" transmission of impulses from one node of Ranvier to the next

The Neuron

3 Types of Neurons

Sensory Neurons

Interneurons

Motor Neurons

Connecting PNS & CNS

Reflex Arc

Reflex Arc

http://youtu.be/wLrhYzdbbpE

Some people are born without pain receptors = dangerous

2. Sensory Neuron

contain sensory receptors that detect stimuli

long myelinated dendrites & short axon

cell body is outside of the spinal cord in the ganglion

function: carry sensory impulses toward the CNS