The Nervous System

Nervous System

One of the two major systems that maintain homeostasis in animals.

Endocrine System

One of the two major systems that maintain homeostasis in animals.

Sensory Function

Senses changes (stimuli) within and external to the body.

Integrative Function

Analyzes sensory information, stores some aspects, and makes decisions.

Motor Function

Responds to stimuli by initiating muscular contractions and glandular secretions.

Central Nervous System (CNS)

Consists of the brain and spinal cord.

Peripheral Nervous System (PNS)

Connects CNS to effectors and relays sensory information from the body to the CNS.

Brain

Analyzes sensory information, creates emotions, thoughts, memories, and stimulates muscle contraction and glandular secretion.

Sensory Neurons

Detect a stimulus and send signals to the brain.

Motor Neurons

Carry signals from the CNS to the PNS to initiate a response.

Neuroglia

One of the two types of cells in nerve tissue that provide support and protection to neurons.

Neurons

Produce and carry nerve impulses throughout the body.

Astrocytes

Neuroglial cells that support the CNS.

Oligodendrocytes

Produce myelin sheaths in the CNS.

Microglia

Phagocytic cells that protect the CNS by engulfing microbes and debris.

Ependymal Cells

Ciliated epithelial cells that line internal brain compartments.

Dendrites

Carry impulses into the cell body of a neuron.

Axons

Carry impulses away from the cell body.

Myelin Sheaths

Composed of lipids and proteins, they protect axons and increase speed of impulse conduction.

White Matter

Areas of the nervous system containing myelinated axons.

Gray Matter

Areas of the nervous system containing unmyelinated axons and neuronal cell bodies.

gray matter

Areas that do not contain myelinated neurons.

three functional classifications of neurons

Sensory Neurons, Motor Neurons, and Interneurons.

synapse

The point between a neuron and another cell.

synaptic cleft

The space between the neuron and the adjacent cell.

neurotransmitters

Carry impulses across the synaptic cleft.

chemical synapses

Use neurotransmitters to carry impulses across a synaptic cleft.

location of chemical synapses

Between neurons, neurons and skeletal muscle fibers, neurons and glands.

acetylcholine

An excitatory neurotransmitter that stimulates muscular activity.

norepinephrine

An excitatory neurotransmitter that stimulates fight or flight responses.

GABA

An inhibitory neurotransmitter that produces a calming effect.

electrical synapses

Allow ions to move directly between neurons and other cells.

Do electrical synapses require neurotransmitters?

No.

membrane potential

An electrical voltage associated with the neuron's cell membrane.

membrane ion channels

Proteins that allow molecules to pass through neuron membranes.

resting membrane potential (RMP)

The charge difference across a neuron's membrane, about -70mV.

cause of RMP

Ion distribution and membrane permeability to sodium and potassium.

action potentials

Impulses that alter and restore the RMP of a neuron.

resting step of impulse formation:

All voltage-gated channels are closed.

depolarization

Neuron membrane becomes permeable to sodium, making inside more positive.

propagation

Impulse wave moves down the axon.

repolarization

Neuron recovers RMP as sodium is removed.

refractory period

Time when a second impulse cannot be created.

reflexes

Rapid, predictable motor responses to stimuli, mostly involuntary.

regulation of reflexes

The spinal cord.

two types of reflexes

Somatic reflexes and Autonomic reflexes.

somatic reflexes

Involve skeletal muscle contractions.

autonomic reflexes

Involve smooth/cardiac muscle and glandular activity.

components of a reflex arc

Receptor, Sensory Neuron, Integration Center, Motor Neuron, Effector.

What are the two major systems that maintain homeostasis in animals?

The Nervous System and the Endocrine System

What are the three functions of the Nervous System?

Sensory Function, Integrative Function, and Motor Function.

What are the two major divisions of the Nervous System?

Central Nervous System (CNS) and Peripheral Nervous System (PNS)

What is the role of the brain in relation to sensory information?

Receives and interprets sensory information.

What are the two types of cells in nerve tissue?

Neuroglia and Neurons.

Are dendrites covered by myelin sheaths?

No