Chapter 4 - Class Powerpoint Flashcards
What are the two main parts of the Nervous System?
The Central Nervous System and the Peripheral Nervous System.
What is the Central Nervous System?
CNS; receives, processes, interprets, and stores incoming sensory information; sends out messages to muscles, glands, organs.
What is the Peripheral Nervous System?
PNS; handles input & output from the CNS; all portions of the nervous system outside the brain and spinal cord. Carries information to and from the nervous system.
What are the two main components of the Central Nervous System?
The brain and the spinal cord.
What does the spinal cord do in the CNS?
The spinal cord is a bridge between the brain and parts of the body below the neck. Spinal nerves are protected by the spinal column; enables spinal reflexes.
What are the two divisions of the PNS?
The Somatic Nervous System and the Autonomic Nervous System.
What is the Somatic Nervous System?
Consists of nerves that carry messages to skeletal muscles (controls voluntary muscles).
What is the Autonomic Nervous System?
Consists of nerves that control involuntary function (vital and automatic processes of the body).
What are the two divisions of the ANS?
The Sympathetic Nervous System and the Parasympathetic Nervous System.
What is the Sympathetic Nervous System?
Becomes most active in emergency situation (fight or flight).
What is the Parasympathetic Nervous System?
Controls ongoing maintenance processes (digestion).
Examples of Parasympathetic Division (9).
Constricts pupils Stimulates tear glands Strongly stimulates salivation Slows heartbeat Constricts bronchial tubes in lungs Activates digestion Inhibits glucose release by liver Contracts bladder wall Stimulates genital erection/vaginal lubrication.
Examples of Sympathetic Division (11).
Dilates pupils Weakly stimulates salivation Stimulates sweat glands Accelerates heartbeat Dilates bronchial tubes in lungs Inhibits digestion Increases epinephrine, norepinephrine secretion by adrenal glands Relaxes bladder wall Decreases urine volume Stimulates glucose release by liver Stimulates ejaculation in males
What is the Nervous System made up of?
Neurons and Glia.
What are Neurons?
Cells that conduct electrochemical signals; basic unit of the nervous system.
What are Glia?
Cells that support, nurture, and insulate neurons, remove debris when neurons die, enhance the formation and maintenance of neural connections, and modify neural functioning.
How are Neurons used in communication?
They transmit electrical signals throughout the body; a basic unit of the Nervous System.
What is the Nervous System?
The communication highway of the body.
What are the three basic types of Neurons?
Sensory Neurons, Motor Neurons, and Interneurons.
What are Sensory Neurons?
Afferent Neurons; they carry sensory messages to the brain.
What are Motor Neurons?
Efferent Neurons; they carry messages from the brain to the muscles of the body.
What are Interneurons?
They connect neurons into networks. Most neurons in the brain and spinal cord and interneurons.
What are the three basic structures of Neurons, and 3 other structures?
The cell body, dendrites, and axon. Other structures: myelin sheath, nodes, synapse.
What is the cell body?
The location on the neuron where the transmitter substances are manufactured.
What are dendrites?
The neuron’s antennae, the receiving site of chemical signals (messages).
What are axons?
The part of the neuron that transmits chemical signals.
What is the myelin sheath?
A protective covering around the axon (of a neuron) made up of glial cells.
What are synapses?
The junction of an axon terminal onto a dendrite.
What is neuron communication?
Electrochemical.
What is activity within the neuron?
Electrical.
What is activity between neurons?
Chemical.
What is the electrical process (of the neuron) created by?
The electrical process is created by a thin membrane around the neuron.
What is the Resting Potential?
When the inside of a neuron is negatively charged, and the exterior is positively charged.
What is Polarization?
An event that occurs when there is a balance between the positive and the negative charges.
What is an Action Potential?
An event that occurs when the membrane becomes stimulated. The pores on the membrane open, allowing positive charges to enter. The neuron is then depolarized, an electrical charge is sent down the axon.
What are the factors affecting neuronal firing?
The “All or None” Principle - if sufficiently stimulated (depolarized), the neuron will to its fullest extent.
The Refractory Period (absolute and relative)
Is there direct contact between neurons?
No, the communication is through synapses (chemical signals). The synapse includes the axon terminal, synaptic cleft, and receptor sites in the membrane of the receiving cell.
What causes the release of neurotransmitters?
The action potential sweeping along the axon.