Nervous Tissue: Neurons, Neuroglia, and Synapses

• Nervous tissue consists of two cell types: neurons and neuroglia.

Neuron Structure

• Neurons contain a nucleus, soma, axon, and dendrites.
• Oligodendrocytes in the central nervous system (CNS) produce the myelin sheath.
• Myelin sheath protects the axon and helps transmit nerve impulses; in the peripheral nervous system (PNS), Schwann cells produce it.
• CNS is the central nervous system.
• PNS is the peripheral nervous system.
• Neuroglia support neurons.
• Oligodendrocytes create the myelin sheath in the CNS.
• Astrocytes remove neurotransmitters from the synaptic cleft.
• Schwann cells create the myelin sheath in the PNS.

Nerve Impulse/Synapse

• Synapse transmits nerve impulses between neurons.
• Neurotransmitters release into the synaptic cleft when a nerve impulse reaches the presynaptic neuron.
• Neurotransmitters bind to receptors on the postsynaptic neuron.
• The union of neurotransmitter and receptor creates a nerve impulse in the postsynaptic neuron.

The Brain

• The thalamus coordinates sensory information.
• The hypothalamus controls hunger, thirst, and the endocrine system via the pituitary gland.
• The pituitary gland is part of the endocrine system.
• The brainstem regulates autonomic functions like heartbeat, breathing, and blood pressure.
• The cerebellum coordinates movement, balance, and spatial orientation.
• The corpus cortex joins the two hemispheres of the brain.

Cerebral Cortex Functions

• Voluntary actions.
• Higher cognitive functions like memory, awareness, and intelligence.