Neuron Structure and Function PDF

## Neuronernes Form - **Unicolor** - one axon, seen in the fetus - **Bipolar** - two axons, seen in the retina of the eye - **Pseudounipolar** - one axon after leaving the cell body, divides into a dendrite and an axon. This type is found in sensitive ganglions - **Multipolar** - many axons, th...

## Neuronernes Form - **Unicolor** - one axon, seen in the fetus - **Bipolar** - two axons, seen in the retina of the eye - **Pseudounipolar** - one axon after leaving the cell body, divides into a dendrite and an axon. This type is found in sensitive ganglions - **Multipolar** - many axons, the longest axon is a neurit (a neuron) ## Neuron Function - **Receptor cells** - receive nerve impulses: - *Exteroceptive* - impulses from the body surface - *Interoceptive* - impulses from internal organ and vessels - *Proprioceptive* - impulses from muscles, tendons, ligaments, joints, the root between the tooth root and the jaw - **Effector cells** - send nerve impulses to muscles and glands - **Integrator cells** - connect receptors to effectors, receive and modify nerve impulses ## Organelles of Neurons: - **Cell membrane** - consists of a double layer of lipids with proteins embedded. Responsible for nerve impulse conduction. - **Neurofibrils** - fine strands that provide support for the neuron - **Microtubules** - **Nissl's substance** - **Golgi apparatus** - **Mitochondria** - found only in living cells - **Centrioles** ## Neuron Structure - **Cell body** - contains the nucleus and cytoplasm. In neurons, the cytoplasm is called *neuroplasm*. ## Nerve Impulse Conduction - Nerve cells are polarized - the inside is negative relative to the outside - The potential difference can be measured at about -80 mV - The potential difference is maintained by a sodium-potassium pump. - When a neuron is stimulated, the permeability of the membrane to sodium ions increases - Sodium ions flow into the cell, causing depolarization. This change in potential is called the *action potential*. - The action potential travels down the axon, causing the release of neurotransmitters at the synapse.