Chapter 11: Functional Organization of Nervous Tissue

functions of the nervous system

11.1: [Term] of the Nervous System

• maintaining homeostasis

• receiving sensory input

• integrating information

• controlling muscles and glands

• establishing and maintaining mental activity

nerves

11.1: Functions of the Nervous System

a collection of many axons bundled together outside the brain and the spinal cord

cranial nerves

11.1: Functions of the Nervous System

• nerve that originates from a nucleus within the brain

• there are 12 pairs

spinal nerves

11.1: Functions of the Nervous System

One of 31 pairs of nerves formed by the joining of the dorsal and ventral roots that arise from the spinal cord.

ganglia

11.1: Functions of the Nervous System

neurons the form clusters of cell bodies outside the brain and spinal cord

plexus

11.1: Functions of the Nervous System

a bundle of nerves outside the brain and the spinal cord

central nervous system (CNS)

11.2: Divisions of the Nervous System

• Major subdivision of the nervous system, consisting of the brain and spinal cord

• receives info from and sends info to the body

peripheral nervous system (PNS)

11.2: Divisions of the Nervous System

• Major subdivision of the nervous system consisting of nerves, ganglia, and sensory receptors branching off of the brain and spinal cord

• responsible for detecting stimuli in and around the body

• has two primary divisions: the sensory and motor divisions

sensory division

11.2: Divisions of the Nervous System: PNS

• transmits electrical signals from specialized receptors in the body toward the CNS

• also called the afferent division (afferent = toward)

• sensory receptors detect stimuli and then send input along nerves

motor division

11.2: Divisions of the Nervous System: PNS

• transmits electrical signals from the CNS to effector organs, such as muscles and glands

• also called the efferent division (efferent = away)

• consists of two branches: the somatic nervous system and the autonomic nervous system

somatic nervous system

11.2: Divisions of the Nervous System: PNS

• Composed of nerve fibers that send impulses from the central nervous system to skeletal muscle

• voluntary division of the motor division

autonomic nervous system (ANS)

11.2: Divisions of the Nervous System: PNS

• Nervous system composed of nerve fibers that send impulses from the central nervous system to smooth muscle, cardiac muscle, and glands.

• involuntary division of the motor division

• has two major subdivisions: the sympathetic division and the parasympathetic division

sympathetic division

11.2: Divisions of the Nervous System: PNS

• readies the body for physical activity

• fight-or-flight division

parasympathetic division

11.2: Divisions of the Nervous System: PNS

• regulates resting functions, such as digesting food or slowing the heart rate

• rest-and-digest division

enteric nervous system

11.2: Divisions of the Nervous System: PNS

consists of neuronal networks within the wall of the digestive tract

neurons

11.3: Cells of the Nervous System: Neuron Structure

• the electrically excitable cells of the nervous system

• consist of 3 parts: the neuron cell body, dendrites, and a single axon

neuron cell body

11.3: Cells of the Nervous System: Neuron Structure

• Enlarged portion of the neuron containing the nucleus and other organelles

• also called nerve cell body or soma

dendrites

11.3: Cells of the Nervous System: Neuron Structure

Branching processes of a neuron; receives stimuli and conducts potentials toward the cell body.

axons

11.3: Cells of the Nervous System: Neuron Structure

Main central process of a neuron that normally conducts action potentials away from the neuron cell body.

multipolar

11.3: Cells of the Nervous System: Types of Neurons

• One of three categories of neurons consisting of a neuron cell body, an axon, and two or more dendrites.

• motor neurons of the PNS and most of the neurons within the CNS are this type

bipolar

11.3: Cells of the Nervous System: Types of Neurons

• One of the three categories of neurons consisting of a neuron with two processes—one dendrite and one axon—arising from opposite poles of the cell body

• the dendrite is often specialized to receive stimulus, and the axon conducts action potentials

• located in some sensory organs, such as the retina of the eye and in the nasal cavity

pseudo unipolar

11.3: Cells of the Nervous System: Types of Neurons

• One of the three categories of neurons consisting of a nerve cell body with a single axon projecting from it.

• most sensory neurons fit this description

anaxonic

11.3: Cells of the Nervous System: Types of Neurons

• do not have axons

• only have dendrites projecting from its cell body

• found within the brain and the retina

• communicates only using graded potentials, and NOT action potentials

sensory neurons

11.3: Cells of the Nervous System: Types of Neurons

• afferent neurons

• conduct action potentials toward the CNS

motor neurons

11.3: Cells of the Nervous System: Types of Neurons

• efferent neurons

• conduct action potentials away from the CNS toward muscles or glands

interneurons

11.3: Cells of the Nervous System: Types of Neurons

conduct action potentials within the CNS from one neuron to another