Anatomy: Exam #3

Parts of a Neuron: A collection of neuron cell bodies outside the CNS is called a ____________.

Ganglion

Parts of a Neuron: The cytoskeleton includes ________________, which assist in moving materials between the cell body and axon.

Microtubules

Neurons of the ________________ nervous system increase heart rate, and neurons of the parasympathetic nervous system slow it down.

Sympathetic Nervous System

The ____________________ nervous system helps support exercise or emergency actions--the so called "fight or flight" responses.

Sympathetic Nervous System

The Autonomic Nervous System is comprised of two branches, the _______________ and __________________ nervous system.

Sympathetic and Parasympathetic Nervous System

The site of communication between two neurons or between a neuron and an effector cell is called a _____________.

Synaptic Bulbe

The tips of some axon terminals swell into bulb-shaped called ______________ ______ _______.

Synaptic End Bulbs

Synaptic End Bulbs contain many tiny membrane-enclosed sacs called _____________ ____________.

Synaptic Vesicles

A ____________ is any change in the environment that is strong enough to initiate an action potential.

Stimulus

An __________ ____________ (nerve impulse) is an electrical signal that propagates (travels) along the surface of the membrane of a neuron.

Action Potential

The ________________ nervous system (ANS) conveys output from the CNS to smooth muscle, cardiac muscle, and glands. Because its motor responses are not normally under conscious control, the action of the ANS is involuntary.

Autonomic Nervous System

Parts of a Neuron: The single ______ of a neuron propagates nerve impulses toward another neuron, a muscle fiber, or a gland cell. An ______ is a long, thin, cylindrical projection that often joins to the cell body at a cone-shaped elevation called the ______ hillock.

Axon

Parts of a Neuron: The cytoplasm of an axon is called the ____________. This is surrounded by a plasma membrane known as the axolemma.

Axoplasm

Parts of a Neuron: The _____ _____, also known as the perikaryon or soma, contains a nucleus surrounded by cytoplasm that includes typical cellular organelles such as lysosomes, mitochondria, and a Golgi Complex.

Cell Body

The __________ nervous system (CNS) consists of the brain and spinal cord. The brain is the part of the CNS that is located in the skull and contains about 85 billion neurons. The spinal cord in connected to the brain through the foramen magnum of the occipital bone and is encircled by bones of the vertebral column. The spinal cord contains about 100 million neurons. The CNS processes many different kinds of sensory information. It is also the source of thoughts, emotions, and memories.

Central Nervous System

Parts of a Neuron: ____________ are the receiving or input portions of a neuron. These are short, tapering, and highly branched.

Dendrites

The _____________ nervous system (ENS), and extensive network of over 100 million neurons confined to the wall of the gastrointestinal (GI) tract. The ENS helps regulate the activity of the smooth muscle and glands of the GI tract. Although the ENS can function independently, it communicates with and is regulated by the other branches of the Autonomic Nervous System.

Enteric Nervous System

Parts of a Neuron: The part of the axon closest to the axon hillock is the _______ _________. In most neurons, nerve impulses arise at the junction of the axon hillock and the initial segment, an area called the trigger zone.

Initial Segment

Functions of the Nervous System: 1. Sensory Function: Sensory receptors detect internal stimuli, such as an increase in blood pressure, or external stimuli (a raindrop landing on your arm). 2. ________________ Function: The nervous system processes sensory information by analyzing it and making decisions for appropriate responses-- and activity known as integration. 3. Motor Function: Once sensory information is integrated, the nervous system may elicit an appropriate motor response by activating effectors (muscles and glands) through cranial and spinal nerves. Stimulation of the effectors causes muscles to contract and glands to secrete.

Integrative Function

Parts of a Neuron: Aging neurons contain ______________, a pigment that occurs as clumps of yellowish brown granules in the cytoplasm.

Lipofuscin

The ________ ___________ of the PNS conveys output from the PNS to effectors (muscles and glands). This division is further subdivided into a somatic nervous system and an autonomic nervous system.

Motor Division

A _________ is a bundle of hundreds to thousands of axons plus associated connective tissue and blood vessels that lies outside the brain and spinal cord. Twelve pairs of cranial _________ emerge from the brain and thirty-one pairs of spinal ________ emerge from the spinal cord. Each _________ follows a defined path and serves a specific region in the body.

Nerve

Parts of a Neuron: A _______ _______ is a general term for any neuronal process that emerges from the cell body of a neuron.

Nerve Fiber

With a mass of only 2kg, about 3% of your body weight, the __________ __________ is one of the smallest and yet the most complex of the 11 body systems. This intricate network of billions of neurons and even more neuroglia is organized into two main subdivisions: the central nervous system and the peripheral nervous system.

Nervous System

Parts of a Neuron: The cytoskeleton includes _________________, composed of bundles of intermediate filaments that provide the cell shape and support and support.

Neurofibrils

Like muscle cells, ___________ possess electrical excitability, the ability to respond to a stimulus and convert into an action potential.

Neurons

Synaptic Vesicles store ____________________. A _______________________ is a molecule released from a synaptic vesicle that excites or inhibits another neuron, muscle fiber, or gland cell. Many neurons contain two or three types of _______________________, each with different effects on the postsynaptic cell.

Neurotransmitters

Parts of a Neuron: Neuronal cell bodies also contain free ribosomes and prominent clusters of rough endoplasmic reticulum, termed ______ bodies.

Nissl Bodies

In general, the ______________________ nervous system takes care of "rest and digest" activities.

Parasympathetic Nervous System

The _______________ nervous system (PNS) consists of all nervous tissue outside the CNS. Components of the PNS include nerves and sensory receptors.

Peripheral Nervous System

The term ___________ _____________ refers to a structure of the nervous system that monitors changes in the external or internal environment. Examples: touch receptors in the skin, photoreceptors of the eye, olfactory (smell) receptors in the nose.

Sensory Receptor

Because some substances synthesized or recycled in the neuron cell body are needed in the axon or at the axon terminals, two types of transport systems carry materials from the cell body to the axon terminals and back. The slower system, which moves materials about 1-5 mm per day, is called _______ axonal transport. It conveys axoplasm in one direction only--- from the cell body toward the axon terminals.

Slow Axonal Transport

The _________ nervous system (SNS) conveys output from the CNS to skeletal muscles only. Because its motor responses can be consciously controlled, the action of this part of the PNS is voluntary.

Somatic Nervous System

Parts of a Neuron: In most neurons, nerve impulses arise at the junction of the axon hillock and the initial segment, an area called the __________ _____.

Trigger Zone