5 The Nervous System Free Online FlashCards

What structures make up the CNS and PNS?

The central nervous system (CNS) consists of the brain and spinal cord; the peripheral nervous system (PNS) includes nerves and ganglia outside the CNS.

What are the main functions of a neuron's dendrites, cell body, and axon?

Dendrites receive incoming signals, the cell body contains the nucleus, and the axon carries signals toward other cells.

Which cells form myelin in the CNS and PNS?

Oligodendrocytes form myelin around CNS axons, while Schwann cells form myelin around PNS axons. Myelin insulates axons and helps signals travel faster.

How do afferent and efferent pathways differ?

Sensory, or afferent, pathways carry information toward the CNS. Motor, or efferent, pathways carry commands away from the CNS to effectors.

Which effectors are controlled by the somatic and autonomic systems?

The somatic system carries sensory information from the body and controls skeletal muscle, usually voluntarily. The autonomic system regulates involuntary activity in smooth muscle, cardiac muscle, and glands.

What does the enteric nervous system regulate?

The enteric nervous system is a network in the digestive tract that helps regulate digestive activity and communicates with the autonomic system.

What triggers an action potential?

When local voltage changes bring a region of a neuron to threshold, it generates an action potential, a brief, all-or-none electrical signal.

How do sodium and potassium movements affect a neuron's membrane?

Sodium ions move into the cell and depolarize the membrane; potassium ions move out and help restore the resting state.

How do nodes of Ranvier speed signaling in myelinated axons?

In myelinated axons, action potentials are renewed at nodes of Ranvier, the gaps in myelin. This lets signals travel rapidly from node to node.

How does a neuron usually communicate across a synapse?

At most synapses, an arriving action potential causes neurotransmitters to cross the synaptic gap and bind to receptors on a target cell, changing its activity.

What functions are supported by the cerebrum?

The cerebrum's two hemispheres support perception, voluntary movement, language, reasoning, and memory.

What are two key roles of the brainstem?

The brainstem connects the brain with the spinal cord and helps regulate essential functions such as breathing and heart activity.